diff mbox series

[v10,1/1] can: usb: etas_es58X: add support for ETAS ES58X CAN USB interfaces

Message ID 20210112130538.14912-2-mailhol.vincent@wanadoo.fr (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series add support for ETAS ES58X CAN USB interfaces | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Guessed tree name to be net-next
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit fail Errors and warnings before: 0 this patch: 18
netdev/kdoc fail Errors and warnings before: 7 this patch: 24
netdev/verify_fixes success Link
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 81 exceeds 80 columns WARNING: line length of 89 exceeds 80 columns WARNING: line length of 93 exceeds 80 columns
netdev/build_allmodconfig_warn fail Errors and warnings before: 0 this patch: 18
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Vincent Mailhol Jan. 12, 2021, 1:05 p.m. UTC
This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
ETAS GmbH (https://www.etas.com/en/products/es58x.php).

Co-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
 drivers/net/can/usb/Kconfig                 |   10 +
 drivers/net/can/usb/Makefile                |    1 +
 drivers/net/can/usb/etas_es58x/Makefile     |    3 +
 drivers/net/can/usb/etas_es58x/es581_4.c    |  552 ++++
 drivers/net/can/usb/etas_es58x/es581_4.h    |  206 ++
 drivers/net/can/usb/etas_es58x/es58x_core.c | 2589 +++++++++++++++++++
 drivers/net/can/usb/etas_es58x/es58x_core.h |  707 +++++
 drivers/net/can/usb/etas_es58x/es58x_fd.c   |  662 +++++
 drivers/net/can/usb/etas_es58x/es58x_fd.h   |  242 ++
 9 files changed, 4972 insertions(+)
 create mode 100644 drivers/net/can/usb/etas_es58x/Makefile
 create mode 100644 drivers/net/can/usb/etas_es58x/es581_4.c
 create mode 100644 drivers/net/can/usb/etas_es58x/es581_4.h
 create mode 100644 drivers/net/can/usb/etas_es58x/es58x_core.c
 create mode 100644 drivers/net/can/usb/etas_es58x/es58x_core.h
 create mode 100644 drivers/net/can/usb/etas_es58x/es58x_fd.c
 create mode 100644 drivers/net/can/usb/etas_es58x/es58x_fd.h

Comments

Vincent Mailhol Jan. 12, 2021, 3:11 p.m. UTC | #1
On Tue. 12 Jan 2021 at 22:05, Vincent Mailhol
<mailhol.vincent@wanadoo.fr> wrote:
>
> This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> ETAS GmbH (https://www.etas.com/en/products/es58x.php).
>
> Co-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> ---
>

Something strange is going on with the mailing list.  I can not
see the second patch (1/1) in the *linux-can* mailing
archive (only the cover letter is present):
https://lore.kernel.org/linux-can/20210112130538.14912-1-mailhol.vincent@wanadoo.fr/T/#

However, the full patch series is present on the *netdev* mailing
archives: https://lore.kernel.org/netdev/20210112130538.14912-2-mailhol.vincent@wanadoo.fr/

Are there any restrictions in regard to the patch size on the
linux-can mailing list? Or did I did anything wrong which
triggered some kind of spam filter?


Yours sincerely,
Vincent
kernel test robot Jan. 12, 2021, 3:29 p.m. UTC | #2
Hi Vincent,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.11-rc3 next-20210111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Vincent-Mailhol/add-support-for-ETAS-ES58X-CAN-USB-interfaces/20210112-211624
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a0d54b4f5b219fb31f0776e9f53aa137e78ae431
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/5f55487bd139c33d619a9c8cd8dbd5cb8b558526
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Vincent-Mailhol/add-support-for-ETAS-ES58X-CAN-USB-interfaces/20210112-211624
        git checkout 5f55487bd139c33d619a9c8cd8dbd5cb8b558526
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/kernel.h:10,
                    from drivers/net/can/usb/etas_es58x/es58x_core.c:13:
   include/linux/scatterlist.h: In function 'sg_set_buf':
   arch/m68k/include/asm/page_mm.h:174:49: warning: ordered comparison of pointer with null pointer [-Wextra]
     174 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
         |                                                 ^~
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   include/linux/scatterlist.h:137:2: note: in expansion of macro 'BUG_ON'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |  ^~~~~~
   include/linux/scatterlist.h:137:10: note: in expansion of macro 'virt_addr_valid'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |          ^~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es58x_core.c: In function 'es58x_can_free_echo_skb_tail':
>> drivers/net/can/usb/etas_es58x/es58x_core.c:393:52: error: 'struct can_skb_priv' has no member named 'frame_len'
     393 |  netdev_completed_queue(netdev, 1, can_skb_prv(skb)->frame_len);
         |                                                    ^~
   drivers/net/can/usb/etas_es58x/es58x_core.c: In function 'es58x_can_get_echo_skb':
>> drivers/net/can/usb/etas_es58x/es58x_core.c:561:29: error: too many arguments to function 'can_get_echo_skb'
     561 |   netdev->stats.tx_bytes += can_get_echo_skb(netdev, tail_idx,
         |                             ^~~~~~~~~~~~~~~~
   In file included from drivers/net/can/usb/etas_es58x/es58x_core.h:19,
                    from drivers/net/can/usb/etas_es58x/es58x_core.c:21:
   include/linux/can/dev.h:247:14: note: declared here
     247 | unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx);
         |              ^~~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es58x_core.c: In function 'es58x_start_xmit':
>> drivers/net/can/usb/etas_es58x/es58x_core.c:2104:14: error: implicit declaration of function 'can_skb_get_frame_len' [-Werror=implicit-function-declaration]
    2104 |  frame_len = can_skb_get_frame_len(skb);
         |              ^~~~~~~~~~~~~~~~~~~~~
>> drivers/net/can/usb/etas_es58x/es58x_core.c:2106:8: error: too many arguments to function 'can_put_echo_skb'
    2106 |  ret = can_put_echo_skb(skb, netdev, skb_idx, frame_len);
         |        ^~~~~~~~~~~~~~~~
   In file included from drivers/net/can/usb/etas_es58x/es58x_core.h:19,
                    from drivers/net/can/usb/etas_es58x/es58x_core.c:21:
   include/linux/can/dev.h:243:5: note: declared here
     243 | int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
         |     ^~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors
--
   In file included from include/linux/kernel.h:10,
                    from drivers/net/can/usb/etas_es58x/es581_4.c:12:
   include/linux/scatterlist.h: In function 'sg_set_buf':
   arch/m68k/include/asm/page_mm.h:174:49: warning: ordered comparison of pointer with null pointer [-Wextra]
     174 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
         |                                                 ^~
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   include/linux/scatterlist.h:137:2: note: in expansion of macro 'BUG_ON'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |  ^~~~~~
   include/linux/scatterlist.h:137:10: note: in expansion of macro 'virt_addr_valid'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |          ^~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es581_4.c: At top level:
>> drivers/net/can/usb/etas_es58x/es581_4.c:532:19: error: 'CAN_FRAME_LEN_MAX' undeclared here (not in a function)
     532 |  .dql_limit_min = CAN_FRAME_LEN_MAX * 50,
         |                   ^~~~~~~~~~~~~~~~~
--
   In file included from include/linux/kernel.h:10,
                    from drivers/net/can/usb/etas_es58x/es58x_fd.c:14:
   include/linux/scatterlist.h: In function 'sg_set_buf':
   arch/m68k/include/asm/page_mm.h:174:49: warning: ordered comparison of pointer with null pointer [-Wextra]
     174 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
         |                                                 ^~
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   include/linux/scatterlist.h:137:2: note: in expansion of macro 'BUG_ON'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |  ^~~~~~
   include/linux/scatterlist.h:137:10: note: in expansion of macro 'virt_addr_valid'
     137 |  BUG_ON(!virt_addr_valid(buf));
         |          ^~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es58x_fd.c: In function 'es58x_fd_rx_can_msg':
>> drivers/net/can/usb/etas_es58x/es58x_fd.c:37:15: error: implicit declaration of function 'canfd_sanitize_len' [-Werror=implicit-function-declaration]
      37 |   __msg_len = canfd_sanitize_len(__msg.len);  \
         |               ^~~~~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es58x_fd.c:123:24: note: in expansion of macro 'es58x_fd_sizeof_rx_tx_msg'
     123 |   u16 rx_can_msg_len = es58x_fd_sizeof_rx_tx_msg(*rx_can_msg);
         |                        ^~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/net/can/usb/etas_es58x/es58x_fd.c: At top level:
>> drivers/net/can/usb/etas_es58x/es58x_fd.c:642:19: error: 'CAN_FRAME_LEN_MAX' undeclared here (not in a function)
     642 |  .dql_limit_min = CAN_FRAME_LEN_MAX * 15,
         |                   ^~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +393 drivers/net/can/usb/etas_es58x/es58x_core.c

   377	
   378	/**
   379	 * es58x_can_free_echo_skb_tail() - Remove the oldest echo skb of the
   380	 *	loopback FIFO.
   381	 * @netdev: CAN network device.
   382	 *
   383	 * Naming convention: the tail is the beginning of the FIFO, i.e. the
   384	 * first skb to have entered the FIFO.
   385	 */
   386	static void es58x_can_free_echo_skb_tail(struct net_device *netdev)
   387	{
   388		struct es58x_priv *priv = es58x_priv(netdev);
   389		u16 tail_idx = priv->echo_skb_tail_idx;
   390		struct sk_buff *skb = priv->can.echo_skb[tail_idx];
   391		unsigned long flags;
   392	
 > 393		netdev_completed_queue(netdev, 1, can_skb_prv(skb)->frame_len);
   394		can_free_echo_skb(netdev, tail_idx);
   395	
   396		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
   397		es58x_add_skb_idx(priv, &priv->echo_skb_tail_idx, 1);
   398		priv->num_echo_skb--;
   399		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
   400	
   401		netdev->stats.tx_dropped++;
   402	}
   403	
   404	/**
   405	 * es58x_can_get_echo_skb_recovery() - Try to re-sync the loopback FIFO.
   406	 * @netdev: CAN network device.
   407	 * @packet_idx: Index
   408	 *
   409	 * This function should not be called under normal circumstances. In
   410	 * the unlikely case that one or several URB packages get dropped by
   411	 * the device, the index will get out of sync. Try to recover by
   412	 * dropping the echo skb packets with older indexes.
   413	 *
   414	 * Return: zero if recovery was successful, -EINVAL otherwise.
   415	 */
   416	static int es58x_can_get_echo_skb_recovery(struct net_device *netdev,
   417						   u32 packet_idx)
   418	{
   419		struct es58x_priv *priv = es58x_priv(netdev);
   420		u32 current_packet_idx, first_packet_idx, num_echo_skb;
   421		unsigned long flags;
   422		int ret = 0;
   423	
   424		netdev->stats.tx_errors++;
   425	
   426		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
   427		current_packet_idx = priv->current_packet_idx;
   428		num_echo_skb = priv->num_echo_skb;
   429		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
   430		first_packet_idx = current_packet_idx - num_echo_skb;
   431	
   432		if (net_ratelimit())
   433			netdev_warn(netdev,
   434				    "Bad loopback packet index: %u. First index: %u, end index %u, num_echo_skb: %02u/%02u\n",
   435				    packet_idx, first_packet_idx,
   436				    current_packet_idx - 1, num_echo_skb,
   437				    priv->can.echo_skb_max);
   438	
   439		if (packet_idx < first_packet_idx) {
   440			if (net_ratelimit())
   441				netdev_warn(netdev,
   442					    "Received loopback is from the past. Ignoring it\n");
   443			ret = -EINVAL;
   444		} else if ((s32)(packet_idx - current_packet_idx) >= 0LL) {
   445			if (net_ratelimit())
   446				netdev_err(netdev,
   447					   "Received loopback is from the future. Ignoring it\n");
   448			ret = -EINVAL;
   449		} else {
   450			if (net_ratelimit())
   451				netdev_warn(netdev,
   452					    "Loopback recovery: dropping %u echo skb from index %u to %u\n",
   453					    packet_idx - first_packet_idx,
   454					    first_packet_idx, packet_idx - 1);
   455			while (first_packet_idx != packet_idx) {
   456				if (num_echo_skb == 0)
   457					return -EINVAL;
   458				es58x_can_free_echo_skb_tail(netdev);
   459				first_packet_idx++;
   460				num_echo_skb--;
   461			}
   462		}
   463		return ret;
   464	}
   465	
   466	/**
   467	 * es58x_can_get_echo_skb() - Get the skb from the loopback FIFO and
   468	 *	loop it back locally.
   469	 * @netdev: CAN network device.
   470	 * @packet_idx: Index of the first packet.
   471	 * @tstamps: Array of hardware timestamps received from a ES58X device.
   472	 * @pkts: Number of packets (and so, length of @tstamps).
   473	 *
   474	 * Callback function for when we receive a self reception acknowledgment.
   475	 * Retrieves the skb from the loopback FIFO, sets its hardware timestamp
   476	 * (the actual time it was sent) and loops it back locally.
   477	 *
   478	 * The device has to be active (i.e. network interface UP and not in
   479	 * bus off state or restarting).
   480	 *
   481	 * Packet indexes must be consecutive (i.e. index of first packet is
   482	 * @packet_idx, index of second packet is @packet_idx + 1 and index of
   483	 * last packet is @packet_idx + @pkts - 1).
   484	 *
   485	 * Return: zero on success.
   486	 */
   487	int es58x_can_get_echo_skb(struct net_device *netdev, u32 packet_idx,
   488				   u64 *tstamps, unsigned int pkts)
   489	{
   490		struct es58x_priv *priv = es58x_priv(netdev);
   491		u16 tail_idx;
   492		u32 first_packet_idx;
   493		unsigned long flags;
   494		unsigned int rx_total_frame_len = 0;
   495		int i;
   496		int ret = 0;
   497	
   498		if (!netif_running(netdev)) {
   499			if (net_ratelimit())
   500				netdev_info(netdev,
   501					    "%s: %s is down, dropping %d loopback packets\n",
   502					    __func__, netdev->name, pkts);
   503			netdev->stats.tx_dropped++;
   504			return 0;
   505		} else if (!es58x_is_can_state_active(netdev)) {
   506			if (net_ratelimit())
   507				netdev_dbg(netdev,
   508					   "Bus is off or device is restarting. Ignoring %u loopback packets from index %u\n",
   509					   pkts, packet_idx);
   510			/* stats.tx_dropped will be (or was already)
   511			 * incremented by
   512			 * drivers/net/can/net/dev.c:can_flush_echo_skb().
   513			 */
   514			return 0;
   515		} else if (priv->num_echo_skb == 0) {
   516			if (net_ratelimit())
   517				netdev_warn(netdev,
   518					    "Received %u loopback packets from index: %u but echo skb queue is empty.\n",
   519					    pkts, packet_idx);
   520			netdev->stats.tx_dropped += pkts;
   521			return 0;
   522		}
   523	
   524		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
   525		first_packet_idx = priv->current_packet_idx - priv->num_echo_skb;
   526		if (first_packet_idx != packet_idx) {
   527			spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
   528			ret = es58x_can_get_echo_skb_recovery(netdev, packet_idx);
   529			if (ret < 0) {
   530				if (net_ratelimit())
   531					netdev_warn(netdev,
   532						    "Could not find echo skb for loopback packet index: %u\n",
   533						    packet_idx);
   534				return 0;
   535			}
   536			spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
   537			first_packet_idx =
   538			    priv->current_packet_idx - priv->num_echo_skb;
   539			WARN_ON(first_packet_idx != packet_idx);
   540		}
   541		tail_idx = priv->echo_skb_tail_idx;
   542		if (priv->num_echo_skb < pkts) {
   543			int pkts_drop = pkts - priv->num_echo_skb;
   544	
   545			if (net_ratelimit())
   546				netdev_err(netdev,
   547					   "Received %u loopback packets but have only %d echo skb. Dropping %d echo skb\n",
   548					   pkts, priv->num_echo_skb, pkts_drop);
   549			netdev->stats.tx_dropped += pkts_drop;
   550			pkts -= pkts_drop;
   551		}
   552		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
   553	
   554		for (i = 0; i < pkts; i++) {
   555			struct sk_buff *skb = priv->can.echo_skb[tail_idx];
   556			unsigned int frame_len = 0;
   557	
   558			if (skb)
   559				es58x_set_skb_timestamp(netdev, skb, tstamps[i]);
   560	
 > 561			netdev->stats.tx_bytes += can_get_echo_skb(netdev, tail_idx,
   562								   &frame_len);
   563			rx_total_frame_len += frame_len;
   564	
   565			es58x_add_skb_idx(priv, &tail_idx, 1);
   566		}
   567	
   568		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
   569		es58x_add_skb_idx(priv, &priv->echo_skb_tail_idx, pkts);
   570		priv->num_echo_skb -= pkts;
   571		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
   572	
   573		netdev_completed_queue(netdev, pkts, rx_total_frame_len);
   574		netdev->stats.tx_packets += pkts;
   575	
   576		priv->err_passive_before_rtx_success = 0;
   577		es58x_netif_wake_queue(netdev);
   578	
   579		return ret;
   580	}
   581	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Vincent Mailhol Jan. 13, 2021, 3:13 a.m. UTC | #3
On Tue 13 Jan 2021 at 00:29, kernel test robot <lkp@intel.com> wrote:
>
> Hi Vincent,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.11-rc3 next-20210111]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]

The patch is applied on linux-can-next/testing. All the warnings
are related to the latest drivers/net/can/dev API changes.

I thought that the test robot only checked the
linux-kernel@vger.kernel.org open list and I didn't bother adding
the "--base". So this is my bad, sorry for that.

Because this is a false positive, I will not send a new
version (unless if requested).


Yours sincerely,
Vincent
Chen, Rong A Jan. 13, 2021, 6:05 a.m. UTC | #4
On 1/13/21 11:13 AM, Vincent MAILHOL wrote:
> On Tue 13 Jan 2021 at 00:29, kernel test robot <lkp@intel.com> wrote:
>> Hi Vincent,
>>
>> Thank you for the patch! Yet something to improve:
>>
>> [auto build test ERROR on linus/master]
>> [also build test ERROR on v5.11-rc3 next-20210111]
>> [If your patch is applied to the wrong git tree, kindly drop us a note.
>> And when submitting patch, we suggest to use '--base' as documented in
>> https://git-scm.com/docs/git-format-patch]
> The patch is applied on linux-can-next/testing. All the warnings
> are related to the latest drivers/net/can/dev API changes.

Hi Vincent,

Thanks for the feedback, we'll try linux-can-next/testing next time.

Best Regards,
Rong Chen

>
> I thought that the test robot only checked the
> linux-kernel@vger.kernel.org open list and I didn't bother adding
> the "--base". So this is my bad, sorry for that.
>
> Because this is a false positive, I will not send a new
> version (unless if requested).
>
>
> Yours sincerely,
> Vincent
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org
Marc Kleine-Budde Jan. 13, 2021, 9:33 a.m. UTC | #5
On 1/12/21 2:05 PM, Vincent Mailhol wrote:
> This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> ETAS GmbH (https://www.etas.com/en/products/es58x.php).
> 
> Co-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>

[...]

> diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
> new file mode 100644
> index 000000000000..30692d78d8e6
> --- /dev/null
> +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
> @@ -0,0 +1,2589 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
> + *
> + * File es58x_core.c: Core logic to manage the network devices and the
> + * USB interface.
> + *
> + * Copyright (C) 2019 Robert Bosch Engineering and Business
> + * Solutions. All rights reserved.
> + * Copyright (C) 2020 ETAS K.K.. All rights reserved.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/usb.h>
> +#include <linux/crc16.h>
> +#include <linux/spinlock.h>
> +#include <asm/unaligned.h>
> +
> +#include "es58x_core.h"
> +
> +#define DRV_VERSION "1.00"
> +MODULE_AUTHOR("Mailhol Vincent <mailhol.vincent@wanadoo.fr>");
> +MODULE_AUTHOR("Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>");
> +MODULE_DESCRIPTION("Socket CAN driver for ETAS ES58X USB adapters");
> +MODULE_VERSION(DRV_VERSION);
> +MODULE_LICENSE("GPL v2");
> +
> +/* Vendor and product id */
> +#define ES58X_MODULE_NAME "etas_es58x"
> +#define ES58X_VENDOR_ID 0x108C
> +#define ES581_4_PRODUCT_ID 0x0159
> +#define ES582_1_PRODUCT_ID 0x0168
> +#define ES584_1_PRODUCT_ID 0x0169
> +
> +/* Table of devices which work with this driver */
> +static const struct usb_device_id es58x_id_table[] = {
> +	{USB_DEVICE(ES58X_VENDOR_ID, ES581_4_PRODUCT_ID)},
> +	{USB_DEVICE(ES58X_VENDOR_ID, ES582_1_PRODUCT_ID)},
> +	{USB_DEVICE(ES58X_VENDOR_ID, ES584_1_PRODUCT_ID)},
> +	{}			/* Terminating entry */
> +};
> +
> +MODULE_DEVICE_TABLE(usb, es58x_id_table);
> +
> +#define es58x_print_hex_dump(buf, len)					\
> +	print_hex_dump(KERN_DEBUG,					\
> +		       ES58X_MODULE_NAME " " __stringify(buf) ": ",	\
> +		       DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> +
> +#define es58x_print_hex_dump_debug(buf, len)				 \
> +	print_hex_dump_debug(ES58X_MODULE_NAME " " __stringify(buf) ": ",\
> +			     DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> +
> +/* The last two bytes of an ES58X command is a CRC16. The first two
> + * bytes (the start of frame) are skipped and the CRC calculation
> + * starts on the third byte.
> + */
> +#define ES58X_CRC_CALC_OFFSET	2
> +
> +/**
> + * es58x_calculate_crc() - Compute the crc16 of a given URB.
> + * @urb_cmd: The URB command for which we want to calculate the CRC.
> + * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
> + *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
> + *
> + * Return: crc16 value.
> + */
> +static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
> +{
> +	u16 crc;
> +	ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
> +
> +	WARN_ON(len < 0);

Is it possible to ensure earlier, that the urbs are of correct length?

> +	crc = crc16(0, &urb_cmd->raw_cmd[ES58X_CRC_CALC_OFFSET], len);
> +	return crc;
> +}

[...]

> +/**
> + * struct es58x_priv - All information specific to a CAN channel.
> + * @can: struct can_priv must be the first member (Socket CAN relies
> + *	on the fact that function netdev_priv() returns a pointer to
> + *	a struct can_priv).
> + * @es58x_dev: pointer to the corresponding ES58X device.
> + * @tx_urb: Used as a buffer to concatenate the TX messages and to do
> + *	a bulk send. Please refer to es58x_start_xmit() for more
> + *	details.
> + * @echo_skb_spinlock: Spinlock to protect the access to the echo skb
> + *	FIFO.
> + * @current_packet_idx: Keeps track of the packet indexes.
> + * @echo_skb_tail_idx: beginning of the echo skb FIFO, i.e. index of
> + *	the first element.
> + * @echo_skb_head_idx: end of the echo skb FIFO plus one, i.e. first
> + *	free index.
> + * @num_echo_skb: actual number of elements in the FIFO. Thus, the end
> + *	of the FIFO is echo_skb_head = (echo_skb_tail_idx +
> + *	num_echo_skb) % can.echo_skb_max.
> + * @tx_total_frame_len: sum, in bytes, of the length of each of the
> + *	CAN messages contained in @tx_urb. To be used as an input of
> + *	netdev_sent_queue() for BQL.
> + * @tx_can_msg_cnt: Number of messages in @tx_urb.
> + * @tx_can_msg_is_fd: false: all messages in @tx_urb are Classical
> + *	CAN, true: all messages in @tx_urb are CAN FD. Rationale:
> + *	ES58X FD devices do not allow to mix Classical CAN and FD CAN
> + *	frames in one single bulk transmission.
> + * @err_passive_before_rtx_success: The ES58X device might enter in a
> + *	state in which it keeps alternating between error passive
> + *	and active state. This counter keeps track of the number of
> + *	error passive and if it gets bigger than
> + *	ES58X_CONSECUTIVE_ERR_PASSIVE_MAX, es58x_rx_err_msg() will
> + *	force the status to bus-off.
> + * @channel_idx: Channel index, starts at zero.
> + */
> +struct es58x_priv {
> +	struct can_priv can;
> +	struct es58x_device *es58x_dev;
> +	struct urb *tx_urb;
> +
> +	spinlock_t echo_skb_spinlock;	/* Comments: c.f. supra */
> +	u32 current_packet_idx;
> +	u16 echo_skb_tail_idx;
> +	u16 echo_skb_head_idx;
> +	u16 num_echo_skb;

Can you explain me how the tx-path works, especially why you need the
current_packet_idx.

In the mcp251xfd driver, the number of TX buffers is a power of two, that makes
things easier. tx_heads % len points to the next buffer to be filled, tx_tail %
len points to the next buffer to be completed. tx_head - tx_tail is the fill
level of the FIFO. This works without spinlocks.

> +
> +	u16 tx_total_frame_len;
> +	u8 tx_can_msg_cnt;
> +	bool tx_can_msg_is_fd;
> +
> +	u8 err_passive_before_rtx_success;
> +
> +	u8 channel_idx;
> +};

Marc
Vincent Mailhol Jan. 13, 2021, 12:15 p.m. UTC | #6
Hi Marc,

Thanks for the comments!

On Wed. 13 Jan 2021 à 18:33, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 1/12/21 2:05 PM, Vincent Mailhol wrote:
> > This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> > ETAS GmbH (https://www.etas.com/en/products/es58x.php).
> >
> > Co-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> > Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
>
> [...]
>
> > diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
> > new file mode 100644
> > index 000000000000..30692d78d8e6
> > --- /dev/null
> > +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
> > @@ -0,0 +1,2589 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
> > + *
> > + * File es58x_core.c: Core logic to manage the network devices and the
> > + * USB interface.
> > + *
> > + * Copyright (C) 2019 Robert Bosch Engineering and Business
> > + * Solutions. All rights reserved.
> > + * Copyright (C) 2020 ETAS K.K.. All rights reserved.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/moduleparam.h>
> > +#include <linux/usb.h>
> > +#include <linux/crc16.h>
> > +#include <linux/spinlock.h>
> > +#include <asm/unaligned.h>
> > +
> > +#include "es58x_core.h"
> > +
> > +#define DRV_VERSION "1.00"
> > +MODULE_AUTHOR("Mailhol Vincent <mailhol.vincent@wanadoo.fr>");
> > +MODULE_AUTHOR("Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>");
> > +MODULE_DESCRIPTION("Socket CAN driver for ETAS ES58X USB adapters");
> > +MODULE_VERSION(DRV_VERSION);
> > +MODULE_LICENSE("GPL v2");
> > +
> > +/* Vendor and product id */
> > +#define ES58X_MODULE_NAME "etas_es58x"
> > +#define ES58X_VENDOR_ID 0x108C
> > +#define ES581_4_PRODUCT_ID 0x0159
> > +#define ES582_1_PRODUCT_ID 0x0168
> > +#define ES584_1_PRODUCT_ID 0x0169
> > +
> > +/* Table of devices which work with this driver */
> > +static const struct usb_device_id es58x_id_table[] = {
> > +     {USB_DEVICE(ES58X_VENDOR_ID, ES581_4_PRODUCT_ID)},
> > +     {USB_DEVICE(ES58X_VENDOR_ID, ES582_1_PRODUCT_ID)},
> > +     {USB_DEVICE(ES58X_VENDOR_ID, ES584_1_PRODUCT_ID)},
> > +     {}                      /* Terminating entry */
> > +};
> > +
> > +MODULE_DEVICE_TABLE(usb, es58x_id_table);
> > +
> > +#define es58x_print_hex_dump(buf, len)                                       \
> > +     print_hex_dump(KERN_DEBUG,                                      \
> > +                    ES58X_MODULE_NAME " " __stringify(buf) ": ",     \
> > +                    DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> > +
> > +#define es58x_print_hex_dump_debug(buf, len)                          \
> > +     print_hex_dump_debug(ES58X_MODULE_NAME " " __stringify(buf) ": ",\
> > +                          DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> > +
> > +/* The last two bytes of an ES58X command is a CRC16. The first two
> > + * bytes (the start of frame) are skipped and the CRC calculation
> > + * starts on the third byte.
> > + */
> > +#define ES58X_CRC_CALC_OFFSET        2
> > +
> > +/**
> > + * es58x_calculate_crc() - Compute the crc16 of a given URB.
> > + * @urb_cmd: The URB command for which we want to calculate the CRC.
> > + * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
> > + *   (ES58X_CRC_CALC_OFFSET + sizeof(crc))
> > + *
> > + * Return: crc16 value.
> > + */
> > +static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
> > +{
> > +     u16 crc;
> > +     ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
> > +
> > +     WARN_ON(len < 0);
>
> Is it possible to ensure earlier, that the urbs are of correct length?

Easy answer: it is ensured. On the Tx branch, I create the urbs so I
know for sure that the length is correct. On the Rx branch, I have a
dedicated function: es58x_check_rx_urb() for this purpose.  I
will remove that WARN_ON() and the one in es58x_get_crc().

I will also check the other WARN_ON() in my code to see if they
can be removed (none on my test throughout the last ten months or
so could trigger any of these WARN_ON() so should be fine to
remove but I will double check).

> > +     crc = crc16(0, &urb_cmd->raw_cmd[ES58X_CRC_CALC_OFFSET], len);
> > +     return crc;
> > +}
>
> [...]
>
> > +/**
> > + * struct es58x_priv - All information specific to a CAN channel.
> > + * @can: struct can_priv must be the first member (Socket CAN relies
> > + *   on the fact that function netdev_priv() returns a pointer to
> > + *   a struct can_priv).
> > + * @es58x_dev: pointer to the corresponding ES58X device.
> > + * @tx_urb: Used as a buffer to concatenate the TX messages and to do
> > + *   a bulk send. Please refer to es58x_start_xmit() for more
> > + *   details.
> > + * @echo_skb_spinlock: Spinlock to protect the access to the echo skb
> > + *   FIFO.
> > + * @current_packet_idx: Keeps track of the packet indexes.
> > + * @echo_skb_tail_idx: beginning of the echo skb FIFO, i.e. index of
> > + *   the first element.
> > + * @echo_skb_head_idx: end of the echo skb FIFO plus one, i.e. first
> > + *   free index.
> > + * @num_echo_skb: actual number of elements in the FIFO. Thus, the end
> > + *   of the FIFO is echo_skb_head = (echo_skb_tail_idx +
> > + *   num_echo_skb) % can.echo_skb_max.
> > + * @tx_total_frame_len: sum, in bytes, of the length of each of the
> > + *   CAN messages contained in @tx_urb. To be used as an input of
> > + *   netdev_sent_queue() for BQL.
> > + * @tx_can_msg_cnt: Number of messages in @tx_urb.
> > + * @tx_can_msg_is_fd: false: all messages in @tx_urb are Classical
> > + *   CAN, true: all messages in @tx_urb are CAN FD. Rationale:
> > + *   ES58X FD devices do not allow to mix Classical CAN and FD CAN
> > + *   frames in one single bulk transmission.
> > + * @err_passive_before_rtx_success: The ES58X device might enter in a
> > + *   state in which it keeps alternating between error passive
> > + *   and active state. This counter keeps track of the number of
> > + *   error passive and if it gets bigger than
> > + *   ES58X_CONSECUTIVE_ERR_PASSIVE_MAX, es58x_rx_err_msg() will
> > + *   force the status to bus-off.
> > + * @channel_idx: Channel index, starts at zero.
> > + */
> > +struct es58x_priv {
> > +     struct can_priv can;
> > +     struct es58x_device *es58x_dev;
> > +     struct urb *tx_urb;
> > +
> > +     spinlock_t echo_skb_spinlock;   /* Comments: c.f. supra */
> > +     u32 current_packet_idx;
> > +     u16 echo_skb_tail_idx;
> > +     u16 echo_skb_head_idx;
> > +     u16 num_echo_skb;
>
> Can you explain me how the tx-path works, especially why you need the
> current_packet_idx.
>
> In the mcp251xfd driver, the number of TX buffers is a power of two, that makes
> things easier. tx_heads % len points to the next buffer to be filled, tx_tail %
> len points to the next buffer to be completed. tx_head - tx_tail is the fill
> level of the FIFO. This works without spinlocks.

For what I understand of your explanations here are the equivalences
between the etas_es58x and the mcp251xfd drivers:

 +--------------------+-------------------+
 | etas_es58x         | mcp251xfd         |
 +--------------------+-------------------+
 | current_packet_idx | tx_head           |
 | echo_skb_tail_idx  | tx_tail % len     |
 | echo_skb_head_idx  | tx_head % len     |
 | num_echo_skb       | tx_head - tx_tail |
 +--------------------+-------------------+

Especially, the current_packet_idx is sent to the device and returned
to the driver upon completion.

I wish the TX buffers were a power of two which is unfortunately not
the case. The theoretical TX buffer sizes are 330 and 500 for the two
devices so I wrote the code to work with those values. The exact size
of the TX buffer is actually even more of a mystery because during
testing both devices were unstable when using the theoretical values
and I had to lower these. There is a comment at the bottom of
es581_4.c and es58x_fd.c to reflect those issues. Because I do not
have access to the source code of the firmware, I could not identify
the root cause.

My understanding is that having a queue size being a power of two is
required in order not to use spinlocks (else, modulo operations would
break when the index wraparound back to zero). I tried to minimize the
number of spinlock: only one per bulk send or bulk receive.


Yours sincerely,
Vincent


> > +
> > +     u16 tx_total_frame_len;
> > +     u8 tx_can_msg_cnt;
> > +     bool tx_can_msg_is_fd;
> > +
> > +     u8 err_passive_before_rtx_success;
> > +
> > +     u8 channel_idx;
> > +};
>
> Marc
>
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
>
Vincent Mailhol Jan. 13, 2021, 2:35 p.m. UTC | #7
On Wed. 13 Jan 2021 at 21:15, Vincent MAILHOL
<mailhol.vincent@wanadoo.fr> wrote:
>
> Hi Marc,
>
> Thanks for the comments!
>
> On Wed. 13 Jan 2021 à 18:33, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
> >
> > On 1/12/21 2:05 PM, Vincent Mailhol wrote:
> > > This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> > > ETAS GmbH (https://www.etas.com/en/products/es58x.php).
> > >
> > > Co-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> > > Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
> > > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> >
> > [...]
> >
> > > diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
> > > new file mode 100644
> > > index 000000000000..30692d78d8e6
> > > --- /dev/null
> > > +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
> > > @@ -0,0 +1,2589 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +
> > > +/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
> > > + *
> > > + * File es58x_core.c: Core logic to manage the network devices and the
> > > + * USB interface.
> > > + *
> > > + * Copyright (C) 2019 Robert Bosch Engineering and Business
> > > + * Solutions. All rights reserved.
> > > + * Copyright (C) 2020 ETAS K.K.. All rights reserved.
> > > + */
> > > +
> > > +#include <linux/kernel.h>
> > > +#include <linux/module.h>
> > > +#include <linux/moduleparam.h>
> > > +#include <linux/usb.h>
> > > +#include <linux/crc16.h>
> > > +#include <linux/spinlock.h>
> > > +#include <asm/unaligned.h>
> > > +
> > > +#include "es58x_core.h"
> > > +
> > > +#define DRV_VERSION "1.00"
> > > +MODULE_AUTHOR("Mailhol Vincent <mailhol.vincent@wanadoo.fr>");
> > > +MODULE_AUTHOR("Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>");
> > > +MODULE_DESCRIPTION("Socket CAN driver for ETAS ES58X USB adapters");
> > > +MODULE_VERSION(DRV_VERSION);
> > > +MODULE_LICENSE("GPL v2");
> > > +
> > > +/* Vendor and product id */
> > > +#define ES58X_MODULE_NAME "etas_es58x"
> > > +#define ES58X_VENDOR_ID 0x108C
> > > +#define ES581_4_PRODUCT_ID 0x0159
> > > +#define ES582_1_PRODUCT_ID 0x0168
> > > +#define ES584_1_PRODUCT_ID 0x0169
> > > +
> > > +/* Table of devices which work with this driver */
> > > +static const struct usb_device_id es58x_id_table[] = {
> > > +     {USB_DEVICE(ES58X_VENDOR_ID, ES581_4_PRODUCT_ID)},
> > > +     {USB_DEVICE(ES58X_VENDOR_ID, ES582_1_PRODUCT_ID)},
> > > +     {USB_DEVICE(ES58X_VENDOR_ID, ES584_1_PRODUCT_ID)},
> > > +     {}                      /* Terminating entry */
> > > +};
> > > +
> > > +MODULE_DEVICE_TABLE(usb, es58x_id_table);
> > > +
> > > +#define es58x_print_hex_dump(buf, len)                                       \
> > > +     print_hex_dump(KERN_DEBUG,                                      \
> > > +                    ES58X_MODULE_NAME " " __stringify(buf) ": ",     \
> > > +                    DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> > > +
> > > +#define es58x_print_hex_dump_debug(buf, len)                          \
> > > +     print_hex_dump_debug(ES58X_MODULE_NAME " " __stringify(buf) ": ",\
> > > +                          DUMP_PREFIX_NONE, 16, 1, buf, len, false)
> > > +
> > > +/* The last two bytes of an ES58X command is a CRC16. The first two
> > > + * bytes (the start of frame) are skipped and the CRC calculation
> > > + * starts on the third byte.
> > > + */
> > > +#define ES58X_CRC_CALC_OFFSET        2
> > > +
> > > +/**
> > > + * es58x_calculate_crc() - Compute the crc16 of a given URB.
> > > + * @urb_cmd: The URB command for which we want to calculate the CRC.
> > > + * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
> > > + *   (ES58X_CRC_CALC_OFFSET + sizeof(crc))
> > > + *
> > > + * Return: crc16 value.
> > > + */
> > > +static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
> > > +{
> > > +     u16 crc;
> > > +     ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
> > > +
> > > +     WARN_ON(len < 0);
> >
> > Is it possible to ensure earlier, that the urbs are of correct length?
>
> Easy answer: it is ensured. On the Tx branch, I create the urbs so I
> know for sure that the length is correct. On the Rx branch, I have a
> dedicated function: es58x_check_rx_urb() for this purpose.  I
> will remove that WARN_ON() and the one in es58x_get_crc().
>
> I will also check the other WARN_ON() in my code to see if they
> can be removed (none on my test throughout the last ten months or
> so could trigger any of these WARN_ON() so should be fine to
> remove but I will double check).
>
> > > +     crc = crc16(0, &urb_cmd->raw_cmd[ES58X_CRC_CALC_OFFSET], len);
> > > +     return crc;
> > > +}
> >
> > [...]
> >
> > > +/**
> > > + * struct es58x_priv - All information specific to a CAN channel.
> > > + * @can: struct can_priv must be the first member (Socket CAN relies
> > > + *   on the fact that function netdev_priv() returns a pointer to
> > > + *   a struct can_priv).
> > > + * @es58x_dev: pointer to the corresponding ES58X device.
> > > + * @tx_urb: Used as a buffer to concatenate the TX messages and to do
> > > + *   a bulk send. Please refer to es58x_start_xmit() for more
> > > + *   details.
> > > + * @echo_skb_spinlock: Spinlock to protect the access to the echo skb
> > > + *   FIFO.
> > > + * @current_packet_idx: Keeps track of the packet indexes.
> > > + * @echo_skb_tail_idx: beginning of the echo skb FIFO, i.e. index of
> > > + *   the first element.
> > > + * @echo_skb_head_idx: end of the echo skb FIFO plus one, i.e. first
> > > + *   free index.
> > > + * @num_echo_skb: actual number of elements in the FIFO. Thus, the end
> > > + *   of the FIFO is echo_skb_head = (echo_skb_tail_idx +
> > > + *   num_echo_skb) % can.echo_skb_max.
> > > + * @tx_total_frame_len: sum, in bytes, of the length of each of the
> > > + *   CAN messages contained in @tx_urb. To be used as an input of
> > > + *   netdev_sent_queue() for BQL.
> > > + * @tx_can_msg_cnt: Number of messages in @tx_urb.
> > > + * @tx_can_msg_is_fd: false: all messages in @tx_urb are Classical
> > > + *   CAN, true: all messages in @tx_urb are CAN FD. Rationale:
> > > + *   ES58X FD devices do not allow to mix Classical CAN and FD CAN
> > > + *   frames in one single bulk transmission.
> > > + * @err_passive_before_rtx_success: The ES58X device might enter in a
> > > + *   state in which it keeps alternating between error passive
> > > + *   and active state. This counter keeps track of the number of
> > > + *   error passive and if it gets bigger than
> > > + *   ES58X_CONSECUTIVE_ERR_PASSIVE_MAX, es58x_rx_err_msg() will
> > > + *   force the status to bus-off.
> > > + * @channel_idx: Channel index, starts at zero.
> > > + */
> > > +struct es58x_priv {
> > > +     struct can_priv can;
> > > +     struct es58x_device *es58x_dev;
> > > +     struct urb *tx_urb;
> > > +
> > > +     spinlock_t echo_skb_spinlock;   /* Comments: c.f. supra */
> > > +     u32 current_packet_idx;
> > > +     u16 echo_skb_tail_idx;
> > > +     u16 echo_skb_head_idx;
> > > +     u16 num_echo_skb;
> >
> > Can you explain me how the tx-path works, especially why you need the
> > current_packet_idx.
> >
> > In the mcp251xfd driver, the number of TX buffers is a power of two, that makes
> > things easier. tx_heads % len points to the next buffer to be filled, tx_tail %
> > len points to the next buffer to be completed. tx_head - tx_tail is the fill
> > level of the FIFO. This works without spinlocks.
>
> For what I understand of your explanations here are the equivalences
> between the etas_es58x and the mcp251xfd drivers:
>
>  +--------------------+-------------------+
>  | etas_es58x         | mcp251xfd         |
>  +--------------------+-------------------+
>  | current_packet_idx | tx_head           |
>  | echo_skb_tail_idx  | tx_tail % len     |
>  | echo_skb_head_idx  | tx_head % len     |
>  | num_echo_skb       | tx_head - tx_tail |
>  +--------------------+-------------------+
>
> Especially, the current_packet_idx is sent to the device and returned
> to the driver upon completion.
>
> I wish the TX buffers were a power of two which is unfortunately not
> the case. The theoretical TX buffer sizes are 330 and 500 for the two
> devices so I wrote the code to work with those values. The exact size
> of the TX buffer is actually even more of a mystery because during
> testing both devices were unstable when using the theoretical values
> and I had to lower these. There is a comment at the bottom of
> es581_4.c and es58x_fd.c to reflect those issues. Because I do not
> have access to the source code of the firmware, I could not identify
> the root cause.
>
> My understanding is that having a queue size being a power of two is
> required in order not to use spinlocks (else, modulo operations would
> break when the index wraparound back to zero). I tried to minimize the
> number of spinlock: only one per bulk send or bulk receive.

Or do you mean to round up the skb_echo array length to the next power
of two in the driver despite the actual size of the device FIFO? Did
not think about that in the past but that should work.

I am going to think a bit more of how to improve that.


Yours sincerely,
Vincent
Marc Kleine-Budde Jan. 13, 2021, 4:04 p.m. UTC | #8
On 1/13/21 1:15 PM, Vincent MAILHOL wrote:
>>> +/**
>>> + * es58x_calculate_crc() - Compute the crc16 of a given URB.
>>> + * @urb_cmd: The URB command for which we want to calculate the CRC.
>>> + * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
>>> + *   (ES58X_CRC_CALC_OFFSET + sizeof(crc))
>>> + *
>>> + * Return: crc16 value.
>>> + */
>>> +static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
>>> +{
>>> +     u16 crc;
>>> +     ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
>>> +
>>> +     WARN_ON(len < 0);
>>
>> Is it possible to ensure earlier, that the urbs are of correct length?
> 
> Easy answer: it is ensured.

Okay, then get rid of those checks :)

> On the Tx branch, I create the urbs so I
> know for sure that the length is correct. On the Rx branch, I have a
> dedicated function: es58x_check_rx_urb() for this purpose.  I
> will remove that WARN_ON() and the one in es58x_get_crc().
> 
> I will also check the other WARN_ON() in my code to see if they
> can be removed (none on my test throughout the last ten months or
> so could trigger any of these WARN_ON() so should be fine to
> remove but I will double check).

[..]

>>> +struct es58x_priv {
>>> +     struct can_priv can;
>>> +     struct es58x_device *es58x_dev;
>>> +     struct urb *tx_urb;
>>> +
>>> +     spinlock_t echo_skb_spinlock;   /* Comments: c.f. supra */
>>> +     u32 current_packet_idx;
>>> +     u16 echo_skb_tail_idx;
>>> +     u16 echo_skb_head_idx;
>>> +     u16 num_echo_skb;
>>
>> Can you explain me how the tx-path works, especially why you need the
>> current_packet_idx.
>>
>> In the mcp251xfd driver, the number of TX buffers is a power of two, that makes
>> things easier. tx_heads % len points to the next buffer to be filled, tx_tail %
>> len points to the next buffer to be completed. tx_head - tx_tail is the fill
>> level of the FIFO. This works without spinlocks.
> 
> For what I understand of your explanations here are the equivalences
> between the etas_es58x and the mcp251xfd drivers:
> 
>  +--------------------+-------------------+
>  | etas_es58x         | mcp251xfd         |
>  +--------------------+-------------------+
>  | current_packet_idx | tx_head           |
>  | echo_skb_tail_idx  | tx_tail % len     |
>  | echo_skb_head_idx  | tx_head % len     |
>  | num_echo_skb       | tx_head - tx_tail |
>  +--------------------+-------------------+
> 
> Especially, the current_packet_idx is sent to the device and returned
> to the driver upon completion.

Is current_packet_idx used only for the TX-PATH?

> I wish the TX buffers were a power of two which is unfortunately not
> the case. The theoretical TX buffer sizes are 330 and 500 for the two
> devices so I wrote the code to work with those values. The exact size
> of the TX buffer is actually even more of a mystery because during
> testing both devices were unstable when using the theoretical values
> and I had to lower these. There is a comment at the bottom of
> es581_4.c and es58x_fd.c to reflect those issues.

What are the performance penalties for using 256 for the fd and 64 ofr the other?

> Because I do not
> have access to the source code of the firmware, I could not identify
> the root cause.

ok

> My understanding is that having a queue size being a power of two is
> required in order not to use spinlocks (else, modulo operations would
> break when the index wraparound back to zero). I tried to minimize the
> number of spinlock: only one per bulk send or bulk receive.

With queue size being power of two the modulo can be written as a mask
operation, so it's reasonable fast. So you only need to care about tx_head and
tx_tail, and there is only one writer for each variable. With a little dance and
barriers when stopping and starting the queue it's race-free without spinlocks.

Marc
Marc Kleine-Budde Jan. 13, 2021, 4:06 p.m. UTC | #9
On 1/13/21 3:35 PM, Vincent MAILHOL wrote:
>> My understanding is that having a queue size being a power of two is
>> required in order not to use spinlocks (else, modulo operations would
>> break when the index wraparound back to zero). I tried to minimize the
>> number of spinlock: only one per bulk send or bulk receive.
> 
> Or do you mean to round up the skb_echo array length to the next power
> of two in the driver despite the actual size of the device FIFO? Did
> not think about that in the past but that should work.
> 
> I am going to think a bit more of how to improve that.

For the echo_skb rounding up might work, but you should round down, so that your
can directly use the masked value.

Marc
Vincent Mailhol Jan. 14, 2021, 3:53 p.m. UTC | #10
On Tue. 14 janv. 2021 at 01:04, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 1/13/21 1:15 PM, Vincent MAILHOL wrote:
> >>> +/**
> >>> + * es58x_calculate_crc() - Compute the crc16 of a given URB.
> >>> + * @urb_cmd: The URB command for which we want to calculate the CRC.
> >>> + * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
> >>> + *   (ES58X_CRC_CALC_OFFSET + sizeof(crc))
> >>> + *
> >>> + * Return: crc16 value.
> >>> + */
> >>> +static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
> >>> +{
> >>> +     u16 crc;
> >>> +     ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
> >>> +
> >>> +     WARN_ON(len < 0);
> >>
> >> Is it possible to ensure earlier, that the urbs are of correct length?
> >
> > Easy answer: it is ensured.
>
> Okay, then get rid of those checks :)
>
> > On the Tx branch, I create the urbs so I
> > know for sure that the length is correct. On the Rx branch, I have a
> > dedicated function: es58x_check_rx_urb() for this purpose.  I
> > will remove that WARN_ON() and the one in es58x_get_crc().
> >
> > I will also check the other WARN_ON() in my code to see if they
> > can be removed (none on my test throughout the last ten months or
> > so could trigger any of these WARN_ON() so should be fine to
> > remove but I will double check).

Checked, all WARN_ON() will be removed in v11.

> >>> +struct es58x_priv {
> >>> +     struct can_priv can;
> >>> +     struct es58x_device *es58x_dev;
> >>> +     struct urb *tx_urb;
> >>> +
> >>> +     spinlock_t echo_skb_spinlock;   /* Comments: c.f. supra */
> >>> +     u32 current_packet_idx;
> >>> +     u16 echo_skb_tail_idx;
> >>> +     u16 echo_skb_head_idx;
> >>> +     u16 num_echo_skb;
> >>
> >> Can you explain me how the tx-path works, especially why you need the
> >> current_packet_idx.
> >>
> >> In the mcp251xfd driver, the number of TX buffers is a power of two, that makes
> >> things easier. tx_heads % len points to the next buffer to be filled, tx_tail %
> >> len points to the next buffer to be completed. tx_head - tx_tail is the fill
> >> level of the FIFO. This works without spinlocks.
> >
> > For what I understand of your explanations here are the equivalences
> > between the etas_es58x and the mcp251xfd drivers:
> >
> >  +--------------------+-------------------+
> >  | etas_es58x         | mcp251xfd         |
> >  +--------------------+-------------------+
> >  | current_packet_idx | tx_head           |
> >  | echo_skb_tail_idx  | tx_tail % len     |
> >  | echo_skb_head_idx  | tx_head % len     |
> >  | num_echo_skb       | tx_head - tx_tail |
> >  +--------------------+-------------------+
> >
> > Especially, the current_packet_idx is sent to the device and returned
> > to the driver upon completion.
>
> Is current_packet_idx used only for the TX-PATH?

It is used in the RX path of loopback packet. When a packet comes
back, its index should be equal to current_packet_idx -
num_echo_skb. I use this in es58x_can_get_echo_skb() to check
that there are no packet drops.

Of course, if the FIFO size is a power of two, the
current_packet_idx would become useless.

> > I wish the TX buffers were a power of two which is unfortunately not
> > the case. The theoretical TX buffer sizes are 330 and 500 for the two
> > devices so I wrote the code to work with those values. The exact size
> > of the TX buffer is actually even more of a mystery because during
> > testing both devices were unstable when using the theoretical values
> > and I had to lower these. There is a comment at the bottom of
> > es581_4.c and es58x_fd.c to reflect those issues.
>
> What are the performance penalties for using 256 for the fd and 64 ofr the other?

I checked my passed log, actually, I had good results with 256 on
the FD. I lowered it to 255 with no strong reasons.

For the classical CAN changing from 75 to 64 should still be
enough to reach full busload.

> > Because I do not
> > have access to the source code of the firmware, I could not identify
> > the root cause.
>
> ok
>
> > My understanding is that having a queue size being a power of two is
> > required in order not to use spinlocks (else, modulo operations would
> > break when the index wraparound back to zero). I tried to minimize the
> > number of spinlock: only one per bulk send or bulk receive.
>
> With queue size being power of two the modulo can be written as a mask
> operation, so it's reasonable fast. So you only need to care about tx_head and
> tx_tail, and there is only one writer for each variable. With a little dance and
> barriers when stopping and starting the queue it's race-free without spinlocks.

Yep, I checked linux/kfifo.h in the past. I think I understand
the theory, now I need to practice.

I will try to do the change. Will get back to you later when it is
done and tested.


Yours sincerely,
Vincent
Oliver Hartkopp Jan. 14, 2021, 5:23 p.m. UTC | #11
Hi Vincent,

On 12.01.21 14:05, Vincent Mailhol wrote:
> This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> ETAS GmbH (https://www.etas.com/en/products/es58x.php).

(..)

> diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c
> new file mode 100644
> index 000000000000..6b9534f23c96
> --- /dev/null
> +++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c

(..)

> +static void es58x_fd_print_bittiming(struct net_device *netdev,
> +				     struct es58x_fd_bittiming
> +				     *es58x_fd_bittiming, char *type)
> +{
> +	netdev_vdbg(netdev, "bitrate %s    = %d\n", type,
> +		    le32_to_cpu(es58x_fd_bittiming->bitrate));
> +	netdev_vdbg(netdev, "tseg1 %s      = %d\n", type,
> +		    le16_to_cpu(es58x_fd_bittiming->tseg1));
> +	netdev_vdbg(netdev, "tseg2 %s      = %d\n", type,
> +		    le16_to_cpu(es58x_fd_bittiming->tseg2));
> +	netdev_vdbg(netdev, "brp %s        = %d\n", type,
> +		    le16_to_cpu(es58x_fd_bittiming->brp));
> +	netdev_vdbg(netdev, "sjw %s        = %d\n", type,
> +		    le16_to_cpu(es58x_fd_bittiming->sjw));
> +}

What is the reason for this code?

These values can be retrieved with the 'ip' tool and are probably 
interesting for development - but not in the final code.

> +
> +static void es58x_fd_print_conf(struct net_device *netdev,
> +				struct es58x_fd_tx_conf_msg *tx_conf_msg)
> +{
> +	es58x_fd_print_bittiming(netdev, &tx_conf_msg->nominal_bittiming,
> +				 "nominal");
> +	netdev_vdbg(netdev, "samples_per_bit    = %d\n",
> +		    tx_conf_msg->samples_per_bit);
> +	netdev_vdbg(netdev, "sync_edge          = %d\n",
> +		    tx_conf_msg->sync_edge);
> +	netdev_vdbg(netdev, "physical_layer     = %d\n",
> +		    tx_conf_msg->physical_layer);
> +	netdev_vdbg(netdev, "self_reception     = %d\n",
> +		    tx_conf_msg->self_reception_mode);
> +	netdev_vdbg(netdev, "ctrlmode           = %d\n", tx_conf_msg->ctrlmode);
> +	netdev_vdbg(netdev, "canfd_enabled      = %d\n",
> +		    tx_conf_msg->canfd_enabled);
> +	if (tx_conf_msg->canfd_enabled) {
> +		es58x_fd_print_bittiming(netdev,
> +					 &tx_conf_msg->data_bittiming, "data");
> +		netdev_vdbg(netdev,
> +			    "Transmitter Delay Compensation        = %d\n",
> +			    tx_conf_msg->tdc);
> +		netdev_vdbg(netdev,
> +			    "Transmitter Delay Compensation Offset = %d\n",
> +			    le16_to_cpu(tx_conf_msg->tdco));
> +		netdev_vdbg(netdev,
> +			    "Transmitter Delay Compensation Filter = %d\n",
> +			    le16_to_cpu(tx_conf_msg->tdcf));
> +	}
> +}

Same here.

Either the information can be retrieved with the 'ip' tool OR the are 
not necessary as set to some reasonable default anyway OR we should 
implement the functionality in the general CAN driver infrastructure.

Regards,
Oliver
Vincent Mailhol Jan. 15, 2021, 12:41 a.m. UTC | #12
On Fri. 15 Jan 2021 at 02:23, Oliver Hartkopp <socketcan@hartkopp.net> wrote:
>
> Hi Vincent,
>
> On 12.01.21 14:05, Vincent Mailhol wrote:
> > This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
> > ETAS GmbH (https://www.etas.com/en/products/es58x.php).
>
> (..)
>
> > diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c
> > new file mode 100644
> > index 000000000000..6b9534f23c96
> > --- /dev/null
> > +++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c
>
> (..)
>
> > +static void es58x_fd_print_bittiming(struct net_device *netdev,
> > +                                  struct es58x_fd_bittiming
> > +                                  *es58x_fd_bittiming, char *type)
> > +{
> > +     netdev_vdbg(netdev, "bitrate %s    = %d\n", type,
> > +                 le32_to_cpu(es58x_fd_bittiming->bitrate));
> > +     netdev_vdbg(netdev, "tseg1 %s      = %d\n", type,
> > +                 le16_to_cpu(es58x_fd_bittiming->tseg1));
> > +     netdev_vdbg(netdev, "tseg2 %s      = %d\n", type,
> > +                 le16_to_cpu(es58x_fd_bittiming->tseg2));
> > +     netdev_vdbg(netdev, "brp %s        = %d\n", type,
> > +                 le16_to_cpu(es58x_fd_bittiming->brp));
> > +     netdev_vdbg(netdev, "sjw %s        = %d\n", type,
> > +                 le16_to_cpu(es58x_fd_bittiming->sjw));
> > +}
>
> What is the reason for this code?
>
> These values can be retrieved with the 'ip' tool and are probably
> interesting for development - but not in the final code.

First thing, I used netdev_vdbg() (verbose debug). That macro
will only produce code if VERBOSE_DEBUG is defined. Normal users
will not see those. So yes, this is mostly for development.

Also, just realised that netdev_vdbg() is barely used
anywhere (only three files use it:
https://elixir.bootlin.com/linux/v5.11-rc3/C/ident/netdev_vdbg).

I guess that I will remove it :)

> > +
> > +static void es58x_fd_print_conf(struct net_device *netdev,
> > +                             struct es58x_fd_tx_conf_msg *tx_conf_msg)
> > +{
> > +     es58x_fd_print_bittiming(netdev, &tx_conf_msg->nominal_bittiming,
> > +                              "nominal");
> > +     netdev_vdbg(netdev, "samples_per_bit    = %d\n",
> > +                 tx_conf_msg->samples_per_bit);
> > +     netdev_vdbg(netdev, "sync_edge          = %d\n",
> > +                 tx_conf_msg->sync_edge);
> > +     netdev_vdbg(netdev, "physical_layer     = %d\n",
> > +                 tx_conf_msg->physical_layer);
> > +     netdev_vdbg(netdev, "self_reception     = %d\n",
> > +                 tx_conf_msg->self_reception_mode);
> > +     netdev_vdbg(netdev, "ctrlmode           = %d\n", tx_conf_msg->ctrlmode);
> > +     netdev_vdbg(netdev, "canfd_enabled      = %d\n",
> > +                 tx_conf_msg->canfd_enabled);
> > +     if (tx_conf_msg->canfd_enabled) {
> > +             es58x_fd_print_bittiming(netdev,
> > +                                      &tx_conf_msg->data_bittiming, "data");
> > +             netdev_vdbg(netdev,
> > +                         "Transmitter Delay Compensation        = %d\n",
> > +                         tx_conf_msg->tdc);
> > +             netdev_vdbg(netdev,
> > +                         "Transmitter Delay Compensation Offset = %d\n",
> > +                         le16_to_cpu(tx_conf_msg->tdco));
> > +             netdev_vdbg(netdev,
> > +                         "Transmitter Delay Compensation Filter = %d\n",
> > +                         le16_to_cpu(tx_conf_msg->tdcf));
> > +     }
> > +}
>
> Same here.
>
> Either the information can be retrieved with the 'ip' tool OR the are
> not necessary as set to some reasonable default anyway

Ack, will remove.

> OR we should
> implement the functionality in the general CAN driver infrastructure.

Would make sense to me to add the tdco (Transmitter Delay
Compensation Offset). Ref: ISO 11898-1 section
11.3.3 "Transmitter delay compensation"

I would just like your opinion on one topic: the tdco is specific
to CAN FD. If we add it, we have two choices:
  1. put it in struct can_bittiming: that will mean that we will
     have an unused field for classical CAN (field bittiming of
     struct can_priv).
  2. put it in struct can_priv (but outside of struct
     can_bittiming): no unused field but less pretty.

I think that 1/ is best.


Yours sincerely,
Vincent
Marc Kleine-Budde Jan. 15, 2021, 7:26 a.m. UTC | #13
On 1/15/21 1:41 AM, Vincent MAILHOL wrote:
> On Fri. 15 Jan 2021 at 02:23, Oliver Hartkopp <socketcan@hartkopp.net> wrote:
>>
>> Hi Vincent,
>>
>> On 12.01.21 14:05, Vincent Mailhol wrote:
>>> This driver supports the ES581.4, ES582.1 and ES584.1 interfaces from
>>> ETAS GmbH (https://www.etas.com/en/products/es58x.php).
>>
>> (..)
>>
>>> diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c
>>> new file mode 100644
>>> index 000000000000..6b9534f23c96
>>> --- /dev/null
>>> +++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c
>>
>> (..)
>>
>>> +static void es58x_fd_print_bittiming(struct net_device *netdev,
>>> +                                  struct es58x_fd_bittiming
>>> +                                  *es58x_fd_bittiming, char *type)
>>> +{
>>> +     netdev_vdbg(netdev, "bitrate %s    = %d\n", type,
>>> +                 le32_to_cpu(es58x_fd_bittiming->bitrate));
>>> +     netdev_vdbg(netdev, "tseg1 %s      = %d\n", type,
>>> +                 le16_to_cpu(es58x_fd_bittiming->tseg1));
>>> +     netdev_vdbg(netdev, "tseg2 %s      = %d\n", type,
>>> +                 le16_to_cpu(es58x_fd_bittiming->tseg2));
>>> +     netdev_vdbg(netdev, "brp %s        = %d\n", type,
>>> +                 le16_to_cpu(es58x_fd_bittiming->brp));
>>> +     netdev_vdbg(netdev, "sjw %s        = %d\n", type,
>>> +                 le16_to_cpu(es58x_fd_bittiming->sjw));
>>> +}
>>
>> What is the reason for this code?
>>
>> These values can be retrieved with the 'ip' tool and are probably
>> interesting for development - but not in the final code.
> 
> First thing, I used netdev_vdbg() (verbose debug). That macro
> will only produce code if VERBOSE_DEBUG is defined. Normal users
> will not see those. So yes, this is mostly for development.
> 
> Also, just realised that netdev_vdbg() is barely used
> anywhere (only three files use it:
> https://elixir.bootlin.com/linux/v5.11-rc3/C/ident/netdev_vdbg).
> 
> I guess that I will remove it :)
> 
>>> +
>>> +static void es58x_fd_print_conf(struct net_device *netdev,
>>> +                             struct es58x_fd_tx_conf_msg *tx_conf_msg)
>>> +{
>>> +     es58x_fd_print_bittiming(netdev, &tx_conf_msg->nominal_bittiming,
>>> +                              "nominal");
>>> +     netdev_vdbg(netdev, "samples_per_bit    = %d\n",
>>> +                 tx_conf_msg->samples_per_bit);
>>> +     netdev_vdbg(netdev, "sync_edge          = %d\n",
>>> +                 tx_conf_msg->sync_edge);
>>> +     netdev_vdbg(netdev, "physical_layer     = %d\n",
>>> +                 tx_conf_msg->physical_layer);
>>> +     netdev_vdbg(netdev, "self_reception     = %d\n",
>>> +                 tx_conf_msg->self_reception_mode);
>>> +     netdev_vdbg(netdev, "ctrlmode           = %d\n", tx_conf_msg->ctrlmode);
>>> +     netdev_vdbg(netdev, "canfd_enabled      = %d\n",
>>> +                 tx_conf_msg->canfd_enabled);
>>> +     if (tx_conf_msg->canfd_enabled) {
>>> +             es58x_fd_print_bittiming(netdev,
>>> +                                      &tx_conf_msg->data_bittiming, "data");
>>> +             netdev_vdbg(netdev,
>>> +                         "Transmitter Delay Compensation        = %d\n",
>>> +                         tx_conf_msg->tdc);
>>> +             netdev_vdbg(netdev,
>>> +                         "Transmitter Delay Compensation Offset = %d\n",
>>> +                         le16_to_cpu(tx_conf_msg->tdco));
>>> +             netdev_vdbg(netdev,
>>> +                         "Transmitter Delay Compensation Filter = %d\n",
>>> +                         le16_to_cpu(tx_conf_msg->tdcf));
>>> +     }
>>> +}
>>
>> Same here.
>>
>> Either the information can be retrieved with the 'ip' tool OR the are
>> not necessary as set to some reasonable default anyway
> 
> Ack, will remove.
> 
>> OR we should
>> implement the functionality in the general CAN driver infrastructure.
> 
> Would make sense to me to add the tdco (Transmitter Delay
> Compensation Offset). Ref: ISO 11898-1 section
> 11.3.3 "Transmitter delay compensation"
> 
> I would just like your opinion on one topic: the tdco is specific
> to CAN FD. If we add it, we have two choices:
>   1. put it in struct can_bittiming: that will mean that we will
>      have an unused field for classical CAN (field bittiming of
>      struct can_priv).
>   2. put it in struct can_priv (but outside of struct
>      can_bittiming): no unused field but less pretty.

3. Deprecate struct can_bittiming as the user space interface
   and transfer each member individually via netlink. Extend
   the kernel-only can_bittiming by the tdc related
   parameters, and add these to the new netlink interface.

I prefer this, as I want to extend the bittiming_const in this way, too. There
are CAN controllers, where the bit timing calculation:

> 	bt->prop_seg = tseg1 / 2;
> 	bt->phase_seg1 = tseg1 - bt->prop_seg;

doesn't work anymore, as they have asymmetric prog_seg and phase_seg1, so that
splitting tseg1 in half doesn't work anymore.

Marc
diff mbox series

Patch

diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
index c1e5d5b570b6..978746ce8873 100644
--- a/drivers/net/can/usb/Kconfig
+++ b/drivers/net/can/usb/Kconfig
@@ -20,6 +20,16 @@  config CAN_ESD_USB2
 	  This driver supports the CAN-USB/2 interface
 	  from esd electronic system design gmbh (http://www.esd.eu).
 
+config CAN_ETAS_ES58X
+	tristate "ETAS ES58X CAN/USB interfaces"
+	select CRC16
+	help
+	  This driver supports the ES581.4, ES582.1 and ES584.1 interfaces
+	  from ETAS GmbH (https://www.etas.com/en/products/es58x.php).
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called etas_es58x.
+
 config CAN_GS_USB
 	tristate "Geschwister Schneider UG interfaces"
 	help
diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
index aa0f17c0b2ed..748cf31a0d53 100644
--- a/drivers/net/can/usb/Makefile
+++ b/drivers/net/can/usb/Makefile
@@ -6,6 +6,7 @@ 
 obj-$(CONFIG_CAN_8DEV_USB) += usb_8dev.o
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
 obj-$(CONFIG_CAN_ESD_USB2) += esd_usb2.o
+obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x/
 obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
 obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
diff --git a/drivers/net/can/usb/etas_es58x/Makefile b/drivers/net/can/usb/etas_es58x/Makefile
new file mode 100644
index 000000000000..a129b4aa0215
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/Makefile
@@ -0,0 +1,3 @@ 
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x.o
+etas_es58x-y = es58x_core.o es581_4.o es58x_fd.o
diff --git a/drivers/net/can/usb/etas_es58x/es581_4.c b/drivers/net/can/usb/etas_es58x/es581_4.c
new file mode 100644
index 000000000000..4080e2bba67d
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es581_4.c
@@ -0,0 +1,552 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es581_4.c: Adds support to ETAS ES581.4.
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+#include "es581_4.h"
+
+/**
+ * es58x_sizeof_rx_tx_msg() - Calculate the actual length of the
+ *	structure of a rx or tx message.
+ * @msg: message of variable length, must have a dlc field.
+ *
+ * Even if RTR frames have actually no payload, the ES58X devices
+ * still expect it. Must be a macro in order to retrieve the actual
+ * size using offsetof() and typeof().
+ *
+ * Return: length of the message.
+ */
+#define es581_4_sizeof_rx_tx_msg(msg)				\
+	offsetof(typeof(msg), data[can_cc_dlc2len((msg).dlc)])
+
+static u16 es581_4_get_msg_len(const union es58x_urb_cmd *urb_cmd)
+{
+	return get_unaligned_le16(&urb_cmd->es581_4_urb_cmd.msg_len);
+}
+
+static int es581_4_rx_loopback_msg(struct es58x_device *es58x_dev,
+				   const struct es581_4_urb_cmd
+				   *es581_4_urb_cmd)
+{
+	struct net_device *netdev;
+	const struct es581_4_bulk_rx_loopback_msg *bulk_rx_loopback_msg;
+	const struct es581_4_rx_loopback_msg *rx_loopback_msg;
+	u64 *tstamps = es58x_dev->timestamps;
+	u16 msg_len;
+	u32 first_packet_idx, packet_idx;
+	unsigned int dropped = 0;
+	int i, num_element, ret;
+
+	bulk_rx_loopback_msg = &es581_4_urb_cmd->bulk_rx_loopback_msg;
+	msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len) -
+	    sizeof(bulk_rx_loopback_msg->channel_no);
+	num_element =
+	    es58x_msg_num_element(es58x_dev->dev,
+				  bulk_rx_loopback_msg->rx_loopback_msg,
+				  msg_len);
+	if (num_element <= 0)
+		return num_element;
+
+	ret = es58x_get_netdev(es58x_dev, bulk_rx_loopback_msg->channel_no,
+			       &netdev);
+	if (ret)
+		return ret;
+
+	rx_loopback_msg = &bulk_rx_loopback_msg->rx_loopback_msg[0];
+	first_packet_idx = get_unaligned_le32(&rx_loopback_msg->packet_idx);
+	packet_idx = first_packet_idx;
+	for (i = 0; i < num_element; i++) {
+		rx_loopback_msg = &bulk_rx_loopback_msg->rx_loopback_msg[i];
+		if (get_unaligned_le32(&rx_loopback_msg->packet_idx)
+		    == packet_idx - 1) {
+			if (net_ratelimit())
+				netdev_warn(netdev,
+					    "Received loopback packet idx %u twice\n",
+					    packet_idx - 1);
+			dropped++;
+			continue;
+		}
+		if (get_unaligned_le32(&rx_loopback_msg->packet_idx)
+		    != packet_idx) {
+			netdev_err(netdev, "Packet idx jumped from %u to %u\n",
+				   packet_idx - 1, rx_loopback_msg->packet_idx);
+			return -EBADMSG;
+		}
+
+		tstamps[i] = get_unaligned_le64(&rx_loopback_msg->timestamp);
+		packet_idx++;
+	}
+
+	netdev->stats.tx_dropped += dropped;
+	return es58x_can_get_echo_skb(netdev, first_packet_idx,
+				      tstamps, num_element - dropped);
+}
+
+static int es581_4_rx_can_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_urb_cmd *es581_4_urb_cmd,
+			      u16 msg_len)
+{
+	const struct device *dev = es58x_dev->dev;
+	struct net_device *netdev;
+	int pkts, num_element, channel_no, ret;
+
+	num_element = es58x_msg_num_element(dev, es581_4_urb_cmd->rx_can_msg,
+					    msg_len);
+	if (num_element <= 0)
+		return num_element;
+
+	channel_no = es581_4_urb_cmd->rx_can_msg[0].channel_no;
+	ret = es58x_get_netdev(es58x_dev, channel_no, &netdev);
+	if (ret)
+		return ret;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d rx packets\n",
+				    __func__, netdev->name, num_element);
+		netdev->stats.rx_dropped += num_element;
+		return 0;
+	}
+
+	for (pkts = 0; pkts < num_element; pkts++) {
+		const struct es581_4_rx_can_msg *rx_can_msg =
+		    &es581_4_urb_cmd->rx_can_msg[pkts];
+		u64 tstamp = get_unaligned_le64(&rx_can_msg->timestamp);
+		canid_t can_id = get_unaligned_le32(&rx_can_msg->can_id);
+
+		if (channel_no != rx_can_msg->channel_no) {
+			netdev_err(netdev,
+				   "%s: channel_no changed from %d to %d\n",
+				   __func__,
+				   channel_no, rx_can_msg->channel_no);
+			return -EBADMSG;
+		}
+
+		ret = es58x_rx_can_msg(netdev, tstamp, rx_can_msg->data,
+				       can_id, rx_can_msg->flags,
+				       rx_can_msg->dlc);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int es581_4_rx_err_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_rx_err_msg *rx_err_msg)
+{
+	struct net_device *netdev;
+	enum es58x_err error = get_unaligned_le32(&rx_err_msg->error);
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_err_msg->channel_no, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_rx_err_msg(netdev, error, 0,
+				get_unaligned_le64(&rx_err_msg->timestamp));
+}
+
+static int es581_4_rx_event_msg(struct es58x_device *es58x_dev,
+				const struct es581_4_rx_event_msg *rx_event_msg)
+{
+	struct net_device *netdev;
+	enum es58x_event event = get_unaligned_le32(&rx_event_msg->event);
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_event_msg->channel_no, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_rx_err_msg(netdev, 0, event,
+				get_unaligned_le64(&rx_event_msg->timestamp));
+}
+
+static int es581_4_rx_cmd_ret_u32(struct es58x_device *es58x_dev,
+				  const struct es581_4_urb_cmd *es581_4_urb_cmd,
+				  enum es58x_ret_type ret_type)
+{
+	struct net_device *netdev;
+	const struct es581_4_rx_dev_ret *rx_dev_ret;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	enum es58x_ret_u32 rx_cmd_ret_u32;
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev,
+				  es581_4_urb_cmd->rx_dev_ret, msg_len);
+	if (ret)
+		return ret;
+
+	rx_dev_ret = &es581_4_urb_cmd->rx_dev_ret;
+
+	ret = es58x_get_netdev(es58x_dev, rx_dev_ret->channel_no, &netdev);
+	if (ret)
+		return ret;
+
+	rx_cmd_ret_u32 = get_unaligned_le32(&rx_dev_ret->rx_cmd_ret_le32);
+	return es58x_rx_cmd_ret_u32(netdev, ret_type, rx_cmd_ret_u32);
+}
+
+static int es581_4_tx_ack_msg(struct es58x_device *es58x_dev,
+			      const struct es581_4_urb_cmd *es581_4_urb_cmd)
+{
+	struct net_device *netdev;
+	const struct es581_4_tx_ack_msg *tx_ack_msg;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	int ret;
+
+	tx_ack_msg = &es581_4_urb_cmd->tx_ack_msg;
+	ret = es58x_check_msg_len(es58x_dev->dev, *tx_ack_msg, msg_len);
+	if (ret)
+		return ret;
+
+	if (tx_ack_msg->rx_dev_ret_u8 != ES58X_RET_U8_OK)
+		return es58x_rx_dev_ret_u8(es58x_dev->dev,
+					   ES58X_RET_TYPE_TX_MSG,
+					   tx_ack_msg->rx_dev_ret_u8);
+
+	ret = es58x_get_netdev(es58x_dev, tx_ack_msg->channel_no, &netdev);
+	if (ret)
+		return ret;
+
+	return
+	    es58x_tx_ack_msg(netdev,
+			     get_unaligned_le16(&tx_ack_msg->tx_free_entries),
+			     ES58X_RET_U32_OK);
+}
+
+static int es581_4_dispatch_rx_cmd(struct es58x_device *es58x_dev,
+				   const struct es581_4_urb_cmd
+				   *es581_4_urb_cmd)
+{
+	const struct device *dev = es58x_dev->dev;
+	u16 msg_len = get_unaligned_le16(&es581_4_urb_cmd->msg_len);
+	enum es581_4_rx_type rx_type = es581_4_urb_cmd->rx_can_msg[0].rx_type;
+	int ret = 0;
+
+	switch (rx_type) {
+	case ES581_4_RX_TYPE_MESSAGE:
+		return es581_4_rx_can_msg(es58x_dev, es581_4_urb_cmd, msg_len);
+
+	case ES581_4_RX_TYPE_ERROR:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_err_msg,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		return es581_4_rx_err_msg(es58x_dev,
+					  &es581_4_urb_cmd->rx_err_msg);
+
+	case ES581_4_RX_TYPE_EVENT:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_event_msg,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		return es581_4_rx_event_msg(es58x_dev,
+					    &es581_4_urb_cmd->rx_event_msg);
+
+	default:
+		dev_err(dev, "%s: Unknown rx_type 0x%02X\n", __func__, rx_type);
+		return -EBADRQC;
+	}
+}
+
+static int es581_4_handle_urb_cmd(struct es58x_device *es58x_dev,
+				  const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es581_4_urb_cmd *es581_4_urb_cmd;
+	const struct device *dev = es58x_dev->dev;
+	u16 msg_len = es581_4_get_msg_len(urb_cmd);
+	int ret;
+
+	es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+
+	if (es581_4_urb_cmd->cmd_type != ES581_4_CAN_COMMAND_TYPE) {
+		dev_err(dev, "%s: Unknown command type (0x%02X)\n",
+			__func__, es581_4_urb_cmd->cmd_type);
+		return -EBADRQC;
+	}
+
+	switch ((enum es581_4_cmd_id)es581_4_urb_cmd->cmd_id) {
+	case ES581_4_CMD_ID_SET_BITTIMING:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_SET_BITTIMING);
+
+	case ES581_4_CMD_ID_ENABLE_CHANNEL:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_ENABLE_CHANNEL);
+
+	case ES581_4_CMD_ID_TX_MSG:
+		return es581_4_tx_ack_msg(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_RX_MSG:
+		return es581_4_dispatch_rx_cmd(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_RESET_RX:
+		ret = es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					     ES58X_RET_TYPE_RESET_RX);
+		return ret;
+
+	case ES581_4_CMD_ID_RESET_TX:
+		ret = es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					     ES58X_RET_TYPE_RESET_TX);
+		return ret;
+
+	case ES581_4_CMD_ID_DISABLE_CHANNEL:
+		return es581_4_rx_cmd_ret_u32(es58x_dev, es581_4_urb_cmd,
+					      ES58X_RET_TYPE_DISABLE_CHANNEL);
+
+	case ES581_4_CMD_ID_TIMESTAMP:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->timestamp,
+					  msg_len);
+		if (ret < 0)
+			return ret;
+		return es58x_rx_timestamp(es58x_dev,
+					  get_unaligned_le64
+					  (&es581_4_urb_cmd->timestamp));
+
+	case ES581_4_CMD_ID_SELF_RECEPTION:
+		return es581_4_rx_loopback_msg(es58x_dev, es581_4_urb_cmd);
+
+	case ES581_4_CMD_ID_DEVICE_ERR:
+		ret = es58x_check_msg_len(dev, es581_4_urb_cmd->rx_dev_ret_u8,
+					  msg_len);
+		if (ret)
+			return ret;
+		return es58x_rx_dev_ret_u8(es58x_dev->dev,
+					   ES58X_RET_TYPE_DEVICE_ERR,
+					   es581_4_urb_cmd->rx_dev_ret_u8);
+
+	default:
+		dev_warn(dev, "%s: Unexpected command ID: 0x%02X\n",
+			 __func__, es581_4_urb_cmd->cmd_id);
+		return -EBADRQC;
+	}
+}
+
+static void es581_4_fill_urb_header(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				    u8 cmd_id, u8 channel_idx, u16 msg_len)
+{
+	struct es581_4_urb_cmd *es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+
+	es581_4_urb_cmd->SOF = cpu_to_le16(es581_4_param.tx_start_of_frame);
+	es581_4_urb_cmd->cmd_type = cmd_type;
+	es581_4_urb_cmd->cmd_id = cmd_id;
+	es581_4_urb_cmd->msg_len = cpu_to_le16(msg_len);
+}
+
+static int es581_4_tx_can_msg(struct es58x_priv *priv, int channel_idx,
+			      u32 packet_idx, const struct sk_buff *skb,
+			      union es58x_urb_cmd *urb_cmd, u32 *urb_cmd_len)
+{
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	struct es581_4_urb_cmd *es581_4_urb_cmd = &urb_cmd->es581_4_urb_cmd;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct es581_4_tx_can_msg *tx_can_msg;
+	u16 msg_len;
+	int ret;
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es581_4_urb_cmd->bulk_tx_can_msg,
+				      es581_4_get_msg_len(urb_cmd) +
+				      sizeof(*tx_can_msg));
+	if (ret)
+		return ret;
+
+	if (can_is_canfd_skb(skb))
+		return -EMSGSIZE;
+
+	/* Fill message contents. */
+	if (*urb_cmd_len == es58x_dev->param->urb_cmd_header_len) {
+		es581_4_fill_urb_header(urb_cmd, ES581_4_CAN_COMMAND_TYPE,
+					ES581_4_CMD_ID_TX_MSG,
+					channel_idx, *urb_cmd_len);
+		msg_len = 1;
+	} else {
+		msg_len = le16_to_cpu(es581_4_urb_cmd->msg_len);
+	}
+	tx_can_msg = (struct es581_4_tx_can_msg *)
+	    &es581_4_urb_cmd->bulk_tx_can_msg.tx_can_msg_buf[msg_len - 1];
+
+	put_unaligned_le32(es58x_get_raw_can_id(cf), &tx_can_msg->can_id);
+	put_unaligned_le32(packet_idx, &tx_can_msg->packet_idx);
+	put_unaligned_le16((u16)es58x_get_flags(skb), &tx_can_msg->flags);
+	tx_can_msg->channel_no = channel_idx + 1;
+	tx_can_msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
+
+	memcpy(tx_can_msg->data, cf->data, cf->len);
+
+	/* Calculate new sizes. */
+	es581_4_urb_cmd->bulk_tx_can_msg.num_can_msg++;
+	msg_len += es581_4_sizeof_rx_tx_msg(*tx_can_msg);
+	*urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	es581_4_urb_cmd->msg_len = cpu_to_le16(msg_len);
+
+	return 0;
+}
+
+static void es581_4_print_conf(struct net_device *netdev,
+			       struct es581_4_tx_conf_msg *tx_conf_msg)
+{
+	netdev_vdbg(netdev, "bitrate         = %d\n",
+		    le32_to_cpu(tx_conf_msg->bitrate));
+	netdev_vdbg(netdev, "sample_point    = %d\n",
+		    le32_to_cpu(tx_conf_msg->sample_point));
+	netdev_vdbg(netdev, "samples_per_bit = %d\n",
+		    le32_to_cpu(tx_conf_msg->samples_per_bit));
+	netdev_vdbg(netdev, "bit_time        = %d\n",
+		    le32_to_cpu(tx_conf_msg->bit_time));
+	netdev_vdbg(netdev, "sjw             = %d\n",
+		    le32_to_cpu(tx_conf_msg->sjw));
+	netdev_vdbg(netdev, "sync_edge       = %d\n",
+		    le32_to_cpu(tx_conf_msg->sync_edge));
+	netdev_vdbg(netdev, "physical_layer  = %d\n",
+		    le32_to_cpu(tx_conf_msg->physical_layer));
+	netdev_vdbg(netdev, "self_reception  = %d\n",
+		    le32_to_cpu(tx_conf_msg->self_reception_mode));
+	netdev_vdbg(netdev, "channel_no      = %d\n", tx_conf_msg->channel_no);
+}
+
+static int es581_4_set_bittiming(struct es58x_device *es58x_dev,
+				 int channel_idx)
+{
+	struct es581_4_tx_conf_msg tx_conf_msg = { 0 };
+	struct net_device *netdev = es58x_dev->netdev[channel_idx];
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+
+	tx_conf_msg.bitrate = cpu_to_le32(bt->bitrate);
+	/* bt->sample_point is in tenth of percent. Convert it to percent. */
+	tx_conf_msg.sample_point = cpu_to_le32(bt->sample_point / 10U);
+	tx_conf_msg.samples_per_bit = cpu_to_le32(ES58X_SAMPLES_PER_BIT_ONE);
+	tx_conf_msg.bit_time = cpu_to_le32(can_bit_time(bt));
+	tx_conf_msg.sjw = cpu_to_le32(bt->sjw);
+	tx_conf_msg.sync_edge = cpu_to_le32(ES58X_SYNC_EDGE_SINGLE);
+	tx_conf_msg.physical_layer =
+	    cpu_to_le32(ES58X_PHYSICAL_LAYER_HIGH_SPEED);
+	tx_conf_msg.self_reception_mode = cpu_to_le32(ES58X_SELF_RECEPTION_ON);
+	tx_conf_msg.channel_no = channel_idx + es581_4_param.channel_idx_offset;
+
+	es581_4_print_conf(netdev, &tx_conf_msg);
+
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_SET_BITTIMING, &tx_conf_msg,
+			      sizeof(tx_conf_msg), channel_idx);
+}
+
+static int es581_4_enable_channel(struct es58x_device *es58x_dev,
+				  int channel_idx)
+{
+	u8 msg = channel_idx + 1;
+
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_ENABLE_CHANNEL, &msg, sizeof(msg),
+			      channel_idx);
+}
+
+static int es581_4_disable_channel(struct es58x_device *es58x_dev,
+				   int channel_idx)
+{
+	u8 msg = channel_idx + 1;
+
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_DISABLE_CHANNEL, &msg, sizeof(msg),
+			      channel_idx);
+}
+
+static int es581_4_reset_rx(struct es58x_device *es58x_dev, int channel_idx)
+{
+	u8 msg = channel_idx + 1;
+
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_RESET_RX, &msg, sizeof(msg),
+			      channel_idx);
+}
+
+static int es581_4_reset_tx(struct es58x_device *es58x_dev, int channel_idx)
+{
+	u8 msg = channel_idx + 1;
+
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_RESET_TX, &msg, sizeof(msg),
+			      channel_idx);
+}
+
+static int es581_4_get_timestamp(struct es58x_device *es58x_dev)
+{
+	return es58x_send_msg(es58x_dev, ES581_4_CAN_COMMAND_TYPE,
+			      ES581_4_CMD_ID_TIMESTAMP, ES58X_EMPTY_MSG,
+			      0, ES58X_CHANNEL_IDX_NA);
+}
+
+/* struct es581_4_bittiming_const - Nominal bittiming constants.
+ *
+ * Nominal bittiming constants for ES581.4 as specified in the
+ * microcontroller datasheet: "Stellaris(R) LM3S5B91 Microcontroller"
+ * table 17-4 "CAN Protocol Ranges" from Texas Instruments.
+ */
+static const struct can_bittiming_const es581_4_bittiming_const = {
+	.name = "ES581.4",
+	.tseg1_min = 1,
+	.tseg1_max = 8,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 128,
+	.brp_inc = 1
+};
+
+const struct es58x_parameters es581_4_param = {
+	.bittiming_const = &es581_4_bittiming_const,
+	.data_bittiming_const = NULL,
+	.bitrate_max = ES58X_MBPS(1),
+	.clock = {.freq = ES58X_MHZ(50)},
+	.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_CC_LEN8_DLC,
+	.tx_start_of_frame = 0xAFAF,
+	.rx_start_of_frame = 0xFAFA,
+	.tx_urb_cmd_max_len = ES581_4_TX_URB_CMD_MAX_LEN,
+	.rx_urb_cmd_max_len = ES581_4_RX_URB_CMD_MAX_LEN,
+	/* Size of internal device TX queue is 330.
+	 *
+	 * However, we witnessed some ES58X_ERR_PROT_CRC errors from
+	 * the device and thus, echo_skb_max was lowered to the
+	 * empirical value of 75 which seems stable.
+	 *
+	 * Root cause of those ES58X_ERR_PROT_CRC errors is still
+	 * unclear.
+	 */
+	.echo_skb_max = 75,
+#ifdef CONFIG_BQL
+	/* Empirical value. */
+	.dql_limit_min = CAN_FRAME_LEN_MAX * 50,
+#endif
+	.tx_bulk_max = ES581_4_TX_BULK_MAX,
+	.urb_cmd_header_len = ES581_4_URB_CMD_HEADER_LEN,
+	.rx_urb_max = ES58X_RX_URBS_MAX,
+	.tx_urb_max = ES58X_TX_URBS_MAX,
+	.channel_idx_offset = 1
+};
+
+const struct es58x_operators es581_4_ops = {
+	.get_msg_len = es581_4_get_msg_len,
+	.handle_urb_cmd = es581_4_handle_urb_cmd,
+	.fill_urb_header = es581_4_fill_urb_header,
+	.tx_can_msg = es581_4_tx_can_msg,
+	.set_bittiming = es581_4_set_bittiming,
+	.enable_channel = es581_4_enable_channel,
+	.disable_channel = es581_4_disable_channel,
+	.reset_rx = es581_4_reset_rx,
+	.reset_tx = es581_4_reset_tx,
+	.get_timestamp = es581_4_get_timestamp
+};
diff --git a/drivers/net/can/usb/etas_es58x/es581_4.h b/drivers/net/can/usb/etas_es58x/es581_4.h
new file mode 100644
index 000000000000..5323f45974da
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es581_4.h
@@ -0,0 +1,206 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es581_4.h: Definitions and declarations specific to ETAS
+ * ES581.4.
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#ifndef __ES581_4_H__
+#define __ES581_4_H__
+
+#include <linux/types.h>
+
+#define ES581_4_NUM_CAN_CH 2
+
+#define ES581_4_TX_BULK_MAX 25
+#define ES581_4_RX_BULK_MAX 30
+#define ES581_4_RX_LOOPBACK_BULK_MAX 30
+
+enum es581_4_cmd_type {
+	ES581_4_CAN_COMMAND_TYPE = 0x45
+};
+
+enum es581_4_cmd_id {
+	ES581_4_CMD_ID_OPEN_CHANNEL = 0x01,
+	ES581_4_CMD_ID_CLOSE_CHANNEL = 0x02,
+	ES581_4_CMD_ID_SET_BITTIMING = 0x03,
+	ES581_4_CMD_ID_ENABLE_CHANNEL = 0x04,
+	ES581_4_CMD_ID_TX_MSG = 0x05,
+	ES581_4_CMD_ID_RX_MSG = 0x06,
+	ES581_4_CMD_ID_RESET_RX = 0x0A,
+	ES581_4_CMD_ID_RESET_TX = 0x0B,
+	ES581_4_CMD_ID_DISABLE_CHANNEL = 0x0C,
+	ES581_4_CMD_ID_TIMESTAMP = 0x0E,
+	ES581_4_CMD_ID_RESET_DEVICE = 0x28,
+	ES581_4_CMD_ID_SELF_RECEPTION = 0x71,
+	ES581_4_CMD_ID_DEVICE_ERR = 0x72
+};
+
+enum es581_4_rx_type {
+	ES581_4_RX_TYPE_MESSAGE = 1,
+	ES581_4_RX_TYPE_ERROR = 3,
+	ES581_4_RX_TYPE_EVENT = 4
+};
+
+/**
+ * struct es581_4_tx_conf_msg - Channel configuration.
+ * @bitrate: Bitrate.
+ * @sample_point: Sample point is in percent [0..100].
+ * @samples_per_bit: type enum es58x_samples_per_bit.
+ * @bit_time: Number of time quanta in one bit.
+ * @sjw: Synchronization Jump Width.
+ * @sync_edge: type enum es58x_sync_edge.
+ * @physical_layer: type enum es58x_physical_layer.
+ * @self_reception_mode: type enum es58x_self_reception_mode.
+ * @channel_no: Channel number, starting from 1. Not to be confused
+ *	with channed_idx of the ES58X FD which starts from 0.
+ */
+struct es581_4_tx_conf_msg {
+	__le32 bitrate;
+	__le32 sample_point;
+	__le32 samples_per_bit;
+	__le32 bit_time;
+	__le32 sjw;
+	__le32 sync_edge;
+	__le32 physical_layer;
+	__le32 self_reception_mode;
+	u8 channel_no;
+} __packed;
+
+struct es581_4_tx_can_msg {
+	__le32 can_id;
+	__le32 packet_idx;
+	__le16 flags;
+	u8 channel_no;
+	u8 dlc;
+	u8 data[CAN_MAX_DLEN];
+} __packed;
+
+/* The ES581.4 allows bulk transfer.  */
+struct es581_4_bulk_tx_can_msg {
+	u8 num_can_msg;
+	/* Using type "u8[]" instead of "struct es581_4_tx_can_msg[]"
+	 * for tx_msg_buf because each member has a flexible size.
+	 */
+	u8 tx_can_msg_buf[ES581_4_TX_BULK_MAX *
+			  sizeof(struct es581_4_tx_can_msg)];
+} __packed;
+
+struct es581_4_rx_loopback_msg {
+	__le64 timestamp;
+	__le32 packet_idx;
+} __packed;
+
+struct es581_4_bulk_rx_loopback_msg {
+	u8 channel_no;
+	struct es581_4_rx_loopback_msg
+	 rx_loopback_msg[ES581_4_RX_LOOPBACK_BULK_MAX];
+} __packed;
+
+/* Normal Rx CAN Message */
+struct es581_4_rx_can_msg {
+	__le64 timestamp;
+	u8 rx_type;		/* type enum es581_4_rx_type */
+	u8 flags;		/* type enum es58x_flag */
+	u8 channel_no;
+	u8 dlc;
+	__le32 can_id;
+	u8 data[CAN_MAX_DLEN];
+} __packed;
+
+struct es581_4_rx_err_msg {
+	__le64 timestamp;
+	__le16 rx_type;		/* type enum es581_4_rx_type */
+	__le16 flags;		/* type enum es58x_flag */
+	u8 channel_no;
+	u8 __padding[2];
+	u8 dlc;
+	__le32 tag;		/* Related to the CAN filtering. Unused in this module */
+	__le32 can_id;
+	__le32 error;		/* type enum es58x_error */
+	__le32 destination;	/* Unused in this module */
+} __packed;
+
+struct es581_4_rx_event_msg {
+	__le64 timestamp;
+	__le16 rx_type;		/* type enum es581_4_rx_type */
+	u8 channel_no;
+	u8 __padding;
+	__le32 tag;		/* Related to the CAN filtering. Unused in this module */
+	__le32 event;		/* type enum es58x_event */
+	__le32 destination;	/* Unused in this module */
+} __packed;
+
+struct es581_4_tx_ack_msg {
+	__le16 tx_free_entries;	/* Number of remaining free entries in the device TX queue */
+	u8 channel_no;
+	u8 rx_dev_ret_u8;	/* type enum es58x_dev_ret_code_u8 */
+} __packed;
+
+struct es581_4_rx_dev_ret {
+	__le32 rx_cmd_ret_le32;
+	u8 channel_no;
+	u8 __padding[3];
+} __packed;
+
+/**
+ * struct es581_4_urb_cmd - Commands received from or sent to the
+ *	ES581.4 device.
+ * @SOF: Start of Frame.
+ * @cmd_type: Command Type (type: enum es581_4_cmd_type). The CRC
+ *	calculation starts at this position.
+ * @cmd_id: Command ID (type: enum es581_4_cmd_id).
+ * @msg_len: Length of the message, excluding CRC (i.e. length of the
+ *	union).
+ * @tx_conf_msg: Channel configuration.
+ * @bulk_tx_can_msg: Tx messages.
+ * @rx_can_msg: Array of Rx messages.
+ * @bulk_rx_loopback_msg: Loopback messages.
+ * @rx_err_msg: Error message.
+ * @rx_event_msg: Event message.
+ * @tx_ack_msg: Tx acknowledgment message.
+ * @timestamp: Timestamp reply.
+ * @rx_cmd_ret_u8: Rx 8 bits return code (type: enum
+ *	es58x_dev_ret_code_u8).
+ * @raw_msg: Message raw payload.
+ * @reserved_for_crc16_do_not_use: The structure ends with a
+ *	CRC16. Because the structures in above union are of variable
+ *	lengths, we can not predict the offset of the CRC in
+ *	advance. Use functions es58x_get_crc() and es58x_set_crc() to
+ *	manipulate it.
+ */
+struct es581_4_urb_cmd {
+	__le16 SOF;
+	u8 cmd_type;
+	u8 cmd_id;
+	__le16 msg_len;
+
+	union {
+		struct es581_4_tx_conf_msg tx_conf_msg;
+		struct es581_4_bulk_tx_can_msg bulk_tx_can_msg;
+		struct es581_4_rx_can_msg rx_can_msg[ES581_4_RX_BULK_MAX];
+		struct es581_4_bulk_rx_loopback_msg bulk_rx_loopback_msg;
+		struct es581_4_rx_err_msg rx_err_msg;
+		struct es581_4_rx_event_msg rx_event_msg;
+		struct es581_4_tx_ack_msg tx_ack_msg;
+		struct es581_4_rx_dev_ret rx_dev_ret;
+		__le64 timestamp;
+		u8 rx_dev_ret_u8;
+		u8 raw_msg[0];
+	} __packed;
+
+	__le16 reserved_for_crc16_do_not_use;
+} __packed;
+
+#define ES581_4_URB_CMD_HEADER_LEN (offsetof(struct es581_4_urb_cmd, raw_msg))
+#define ES581_4_TX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es581_4_urb_cmd, bulk_tx_can_msg)
+#define ES581_4_RX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es581_4_urb_cmd, rx_can_msg)
+
+#endif /* __ES581_4_H__ */
diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
new file mode 100644
index 000000000000..30692d78d8e6
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
@@ -0,0 +1,2589 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_core.c: Core logic to manage the network devices and the
+ * USB interface.
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/usb.h>
+#include <linux/crc16.h>
+#include <linux/spinlock.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+
+#define DRV_VERSION "1.00"
+MODULE_AUTHOR("Mailhol Vincent <mailhol.vincent@wanadoo.fr>");
+MODULE_AUTHOR("Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>");
+MODULE_DESCRIPTION("Socket CAN driver for ETAS ES58X USB adapters");
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE("GPL v2");
+
+/* Vendor and product id */
+#define ES58X_MODULE_NAME "etas_es58x"
+#define ES58X_VENDOR_ID 0x108C
+#define ES581_4_PRODUCT_ID 0x0159
+#define ES582_1_PRODUCT_ID 0x0168
+#define ES584_1_PRODUCT_ID 0x0169
+
+/* Table of devices which work with this driver */
+static const struct usb_device_id es58x_id_table[] = {
+	{USB_DEVICE(ES58X_VENDOR_ID, ES581_4_PRODUCT_ID)},
+	{USB_DEVICE(ES58X_VENDOR_ID, ES582_1_PRODUCT_ID)},
+	{USB_DEVICE(ES58X_VENDOR_ID, ES584_1_PRODUCT_ID)},
+	{}			/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, es58x_id_table);
+
+#define es58x_print_hex_dump(buf, len)					\
+	print_hex_dump(KERN_DEBUG,					\
+		       ES58X_MODULE_NAME " " __stringify(buf) ": ",	\
+		       DUMP_PREFIX_NONE, 16, 1, buf, len, false)
+
+#define es58x_print_hex_dump_debug(buf, len)				 \
+	print_hex_dump_debug(ES58X_MODULE_NAME " " __stringify(buf) ": ",\
+			     DUMP_PREFIX_NONE, 16, 1, buf, len, false)
+
+/* The last two bytes of an ES58X command is a CRC16. The first two
+ * bytes (the start of frame) are skipped and the CRC calculation
+ * starts on the third byte.
+ */
+#define ES58X_CRC_CALC_OFFSET	2
+
+/**
+ * es58x_calculate_crc() - Compute the crc16 of a given URB.
+ * @urb_cmd: The URB command for which we want to calculate the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: crc16 value.
+ */
+static u16 es58x_calculate_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	ssize_t len = urb_len - ES58X_CRC_CALC_OFFSET - sizeof(crc);
+
+	WARN_ON(len < 0);
+	crc = crc16(0, &urb_cmd->raw_cmd[ES58X_CRC_CALC_OFFSET], len);
+	return crc;
+}
+
+/**
+ * es58x_get_crc() - Get the CRC value of a given URB.
+ * @urb_cmd: The URB command for which we want to get the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: crc16 value.
+ */
+static u16 es58x_get_crc(const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	const __le16 *crc_addr;
+
+	WARN_ON(urb_len - (ssize_t)sizeof(crc) < 0);
+	crc_addr = (__le16 *)&urb_cmd->raw_cmd[urb_len - sizeof(crc)];
+	crc = get_unaligned_le16(crc_addr);
+	return crc;
+}
+
+/**
+ * es58x_set_crc() - Set the CRC value of a given URB.
+ * @urb_cmd: The URB command for which we want to get the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ */
+static void es58x_set_crc(union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 crc;
+	__le16 *crc_addr;
+
+	crc = es58x_calculate_crc(urb_cmd, urb_len);
+	crc_addr = (__le16 *)&urb_cmd->raw_cmd[urb_len - sizeof(crc)];
+	put_unaligned_le16(crc, crc_addr);
+}
+
+/**
+ * es58x_check_crc() - Validate the CRC value of a given URB.
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command for which we want to check the CRC.
+ * @urb_len: Length of @urb_cmd. Must be at least bigger than 4
+ *	(ES58X_CRC_CALC_OFFSET + sizeof(crc))
+ *
+ * Return: zero on success, -EBADMSG if the CRC check fails.
+ */
+static int es58x_check_crc(struct es58x_device *es58x_dev,
+			   const union es58x_urb_cmd *urb_cmd, u16 urb_len)
+{
+	u16 calculated_crc = es58x_calculate_crc(urb_cmd, urb_len);
+	u16 expected_crc = es58x_get_crc(urb_cmd, urb_len);
+
+	if (expected_crc != calculated_crc) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Bad CRC, urb_len: %d\n",
+				    __func__, urb_len);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_timestamp_to_ns() - Convert a timestamp value received from a
+ *	ES58X device to nanoseconds.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * The timestamp received from ES58X is expressed in multiple of 0.5
+ * micro seconds. This function converts it in to nanoseconds.
+ *
+ * Return: Timestamp value in nanoseconds.
+ */
+static u64 es58x_timestamp_to_ns(u64 timestamp)
+{
+	const u64 es58x_timestamp_ns_mult_coef = 500ULL;
+
+	return es58x_timestamp_ns_mult_coef * timestamp;
+}
+
+/**
+ * es58x_set_skb_timestamp() - Set the hardware timestamp of an skb.
+ * @netdev: CAN network device.
+ * @skb: socket buffer of a CAN message.
+ * @timestamp: Timestamp received from an ES58X device.
+ *
+ * Used for both received and loopback messages.
+ *
+ * Return: zero on success, -EFAULT if @skb is NULL.
+ */
+static int es58x_set_skb_timestamp(struct net_device *netdev,
+				   struct sk_buff *skb, u64 timestamp)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	struct skb_shared_hwtstamps *hwts;
+
+	hwts = skb_hwtstamps(skb);
+	/* Ignoring overflow (overflow on 64 bits timestamp with nano
+	 * second precision would occur after more than 500 years).
+	 */
+	hwts->hwtstamp = ns_to_ktime(es58x_timestamp_to_ns(timestamp) +
+				     es58x_dev->realtime_diff_ns);
+
+	return 0;
+}
+
+/**
+ * es58x_rx_timestamp() - Handle a received timestamp.
+ * @es58x_dev: ES58X device.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * Calculate the difference between the ES58X device and the kernel
+ * internal clocks. This difference will be later used as an offset to
+ * convert the timestamps of RX and loopback messages to match the
+ * kernel system time (e.g. convert to UNIX time).
+ *
+ * Return: zero on success.
+ */
+int es58x_rx_timestamp(struct es58x_device *es58x_dev, u64 timestamp)
+{
+	u64 ktime_real_ns = ktime_get_real_ns();
+	u64 device_timestamp = es58x_timestamp_to_ns(timestamp);
+
+	dev_dbg(es58x_dev->dev, "%s: request round-trip time: %llu ns\n",
+		__func__, ktime_real_ns - es58x_dev->ktime_req_ns);
+
+	es58x_dev->realtime_diff_ns =
+	    (es58x_dev->ktime_req_ns + ktime_real_ns) / 2 - device_timestamp;
+	es58x_dev->ktime_req_ns = 0;
+
+	dev_dbg(es58x_dev->dev,
+		"%s: Device timestamp: %llu, diff with kernel: %llu\n",
+		__func__, device_timestamp, es58x_dev->realtime_diff_ns);
+
+	return 0;
+}
+
+/**
+ * es58x_set_realtime_diff_ns() - Calculate difference between the
+ *	clocks of the ES58X device and the kernel
+ * @es58x_dev: ES58X device.
+ *
+ * Request a timestamp from the ES58X device. Once the answer is
+ * received, the timestamp difference will be set by the callback
+ * function es58x_rx_timestamp().
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_set_realtime_diff_ns(struct es58x_device *es58x_dev)
+{
+	if (es58x_dev->ktime_req_ns) {
+		dev_warn(es58x_dev->dev,
+			 "%s: Previous request to set timestamp has not completed yet\n",
+			 __func__);
+		return -EBUSY;
+	}
+
+	es58x_dev->ktime_req_ns = ktime_get_real_ns();
+	return es58x_dev->ops->get_timestamp(es58x_dev);
+}
+
+/**
+ * es58x_is_can_state_active() - Is the network device in an active
+ *	CAN state?
+ * @netdev: CAN network device.
+ *
+ * The device is considered active if it is able to send or receive
+ * CAN frames, that is to say if it is in any of
+ * CAN_STATE_ERROR_ACTIVE, CAN_STATE_ERROR_WARNING or
+ * CAN_STATE_ERROR_PASSIVE states.
+ *
+ * Caution: when recovering from a bus-off,
+ * net/core/dev.c#can_restart() will call
+ * net/core/dev.c#can_flush_echo_skb() without using any kind of
+ * locks. For this reason, it is critical to guaranty that no TX or
+ * loopback operations (i.e. any access to priv->echo_skb[]) can be
+ * done while this function is returning false.
+ *
+ * Return: true if the device is active, else returns false.
+ */
+static bool es58x_is_can_state_active(struct net_device *netdev)
+{
+	return es58x_priv(netdev)->can.state < CAN_STATE_BUS_OFF;
+}
+
+/**
+ * es58x_echo_skb_stop_threshold() - Determine the limit of how many
+ *	skb slots can be taken before we should stop the network
+ *	queue.
+ * @priv: ES58X private parameters related to the network device.
+ *
+ * We need to save enough free skb slots in order to be able to do
+ * bulk send. This function can be used to determine when to wake or
+ * stop the network queue in regard to the number of skb slots already
+ * taken if the loopback FIFO.
+ *
+ * Return: stop threshold limit.
+ */
+static int es58x_echo_skb_stop_threshold(struct es58x_priv *priv)
+{
+	return priv->can.echo_skb_max - priv->es58x_dev->param->tx_bulk_max + 1;
+}
+
+/**
+ * es58x_netif_wake_queue() - Wake-up the network queue if conditions
+ *	are met.
+ * @netdev: CAN network device.
+ *
+ * If the queue is already awoken, do nothing.
+ *
+ * The conditions to wake up the queue are: a.) The device should be
+ * active (e.g. not in bus off state), b.) The network device must be
+ * up, c.) The echo_skb must have enough free slots for a bulk sent
+ * (c.f. es58x_echo_skb_stop_threshold()), d.) Enough idle URBs should
+ * be available.
+ */
+static void es58x_netif_wake_queue(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	unsigned long echo_skb_flags, tx_urbs_flags;
+
+	if (!netif_queue_stopped(netdev))
+		return;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, echo_skb_flags);
+	if (!es58x_is_can_state_active(netdev))
+		goto echo_skb_unlock;
+	if (netif_running(netdev) &&
+	    priv->num_echo_skb < es58x_echo_skb_stop_threshold(priv)) {
+		/* Confirm that we have at least one idle URB per CAN
+		 * network device. Otherwise, we might run into race
+		 * conditions in the function es58x_start_xmit() which
+		 * would force us to return NETDEV_TX_BUSY.
+		 */
+		spin_lock_irqsave(&es58x_dev->tx_urbs_idle.lock, tx_urbs_flags);
+		if (atomic_read(&es58x_dev->tx_urbs_idle_cnt) >=
+		    es58x_dev->num_can_ch)
+			netif_wake_queue(netdev);
+		spin_unlock_irqrestore(&es58x_dev->tx_urbs_idle.lock,
+				       tx_urbs_flags);
+	}
+ echo_skb_unlock:
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, echo_skb_flags);
+}
+
+/**
+ * es58x_netif_wake_all_queues() - Wake-up all the network queues if
+ *	conditions are met.
+ * @es58x_dev: ES58X device.
+ *
+ * Try to wake-up all the queues associated with a ES58X device. This
+ * function should be used when idle URB resources become available.
+ */
+static void es58x_netif_wake_all_queues(struct es58x_device *es58x_dev)
+{
+	int i;
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++)
+		es58x_netif_wake_queue(es58x_dev->netdev[i]);
+}
+
+/**
+ * es58x_netif_stop_all_queues() - Unconditionally stop all the
+ *	network queues.
+ * @es58x_dev: ES58X device.
+ *
+ * Stop all the queues associated with a ES58X device. This
+ * function should be used when idle URB resources become unavailable.
+ */
+static void es58x_netif_stop_all_queues(struct es58x_device *es58x_dev)
+{
+	int i;
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++)
+		if (es58x_dev->netdev[i])
+			netif_stop_queue(es58x_dev->netdev[i]);
+}
+
+/**
+ * es58x_add_skb_idx() - Increment an index of the loopback FIFO.
+ * @priv: ES58X private parameters related to the network device.
+ * @idx: address of the index to be incremented.
+ * @a: the increment. Must be positive and less or equal to
+ *	@priv->can.echo_skb_max.
+ *
+ * Do a modulus addition: set *@idx to (*@idx + @a) %
+ * @priv->can.echo_skb_max.
+ *
+ * Rationale: the modulus operator % takes a decent amount of CPU
+ * cycles (c.f. other division functions such as
+ * include/linux/math64.h:iter_div_u64_rem()).
+ */
+static __always_inline void es58x_add_skb_idx(struct es58x_priv *priv,
+					      u16 *idx, u16 a)
+{
+	*idx += a;
+	if (*idx >= priv->can.echo_skb_max)
+		*idx -= priv->can.echo_skb_max;
+}
+
+/**
+ * es58x_can_free_echo_skb_tail() - Remove the oldest echo skb of the
+ *	loopback FIFO.
+ * @netdev: CAN network device.
+ *
+ * Naming convention: the tail is the beginning of the FIFO, i.e. the
+ * first skb to have entered the FIFO.
+ */
+static void es58x_can_free_echo_skb_tail(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	u16 tail_idx = priv->echo_skb_tail_idx;
+	struct sk_buff *skb = priv->can.echo_skb[tail_idx];
+	unsigned long flags;
+
+	netdev_completed_queue(netdev, 1, can_skb_prv(skb)->frame_len);
+	can_free_echo_skb(netdev, tail_idx);
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	es58x_add_skb_idx(priv, &priv->echo_skb_tail_idx, 1);
+	priv->num_echo_skb--;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	netdev->stats.tx_dropped++;
+}
+
+/**
+ * es58x_can_get_echo_skb_recovery() - Try to re-sync the loopback FIFO.
+ * @netdev: CAN network device.
+ * @packet_idx: Index
+ *
+ * This function should not be called under normal circumstances. In
+ * the unlikely case that one or several URB packages get dropped by
+ * the device, the index will get out of sync. Try to recover by
+ * dropping the echo skb packets with older indexes.
+ *
+ * Return: zero if recovery was successful, -EINVAL otherwise.
+ */
+static int es58x_can_get_echo_skb_recovery(struct net_device *netdev,
+					   u32 packet_idx)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	u32 current_packet_idx, first_packet_idx, num_echo_skb;
+	unsigned long flags;
+	int ret = 0;
+
+	netdev->stats.tx_errors++;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	current_packet_idx = priv->current_packet_idx;
+	num_echo_skb = priv->num_echo_skb;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+	first_packet_idx = current_packet_idx - num_echo_skb;
+
+	if (net_ratelimit())
+		netdev_warn(netdev,
+			    "Bad loopback packet index: %u. First index: %u, end index %u, num_echo_skb: %02u/%02u\n",
+			    packet_idx, first_packet_idx,
+			    current_packet_idx - 1, num_echo_skb,
+			    priv->can.echo_skb_max);
+
+	if (packet_idx < first_packet_idx) {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Received loopback is from the past. Ignoring it\n");
+		ret = -EINVAL;
+	} else if ((s32)(packet_idx - current_packet_idx) >= 0LL) {
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Received loopback is from the future. Ignoring it\n");
+		ret = -EINVAL;
+	} else {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Loopback recovery: dropping %u echo skb from index %u to %u\n",
+				    packet_idx - first_packet_idx,
+				    first_packet_idx, packet_idx - 1);
+		while (first_packet_idx != packet_idx) {
+			if (num_echo_skb == 0)
+				return -EINVAL;
+			es58x_can_free_echo_skb_tail(netdev);
+			first_packet_idx++;
+			num_echo_skb--;
+		}
+	}
+	return ret;
+}
+
+/**
+ * es58x_can_get_echo_skb() - Get the skb from the loopback FIFO and
+ *	loop it back locally.
+ * @netdev: CAN network device.
+ * @packet_idx: Index of the first packet.
+ * @tstamps: Array of hardware timestamps received from a ES58X device.
+ * @pkts: Number of packets (and so, length of @tstamps).
+ *
+ * Callback function for when we receive a self reception acknowledgment.
+ * Retrieves the skb from the loopback FIFO, sets its hardware timestamp
+ * (the actual time it was sent) and loops it back locally.
+ *
+ * The device has to be active (i.e. network interface UP and not in
+ * bus off state or restarting).
+ *
+ * Packet indexes must be consecutive (i.e. index of first packet is
+ * @packet_idx, index of second packet is @packet_idx + 1 and index of
+ * last packet is @packet_idx + @pkts - 1).
+ *
+ * Return: zero on success.
+ */
+int es58x_can_get_echo_skb(struct net_device *netdev, u32 packet_idx,
+			   u64 *tstamps, unsigned int pkts)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	u16 tail_idx;
+	u32 first_packet_idx;
+	unsigned long flags;
+	unsigned int rx_total_frame_len = 0;
+	int i;
+	int ret = 0;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d loopback packets\n",
+				    __func__, netdev->name, pkts);
+		netdev->stats.tx_dropped++;
+		return 0;
+	} else if (!es58x_is_can_state_active(netdev)) {
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Bus is off or device is restarting. Ignoring %u loopback packets from index %u\n",
+				   pkts, packet_idx);
+		/* stats.tx_dropped will be (or was already)
+		 * incremented by
+		 * drivers/net/can/net/dev.c:can_flush_echo_skb().
+		 */
+		return 0;
+	} else if (priv->num_echo_skb == 0) {
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Received %u loopback packets from index: %u but echo skb queue is empty.\n",
+				    pkts, packet_idx);
+		netdev->stats.tx_dropped += pkts;
+		return 0;
+	}
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	first_packet_idx = priv->current_packet_idx - priv->num_echo_skb;
+	if (first_packet_idx != packet_idx) {
+		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+		ret = es58x_can_get_echo_skb_recovery(netdev, packet_idx);
+		if (ret < 0) {
+			if (net_ratelimit())
+				netdev_warn(netdev,
+					    "Could not find echo skb for loopback packet index: %u\n",
+					    packet_idx);
+			return 0;
+		}
+		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+		first_packet_idx =
+		    priv->current_packet_idx - priv->num_echo_skb;
+		WARN_ON(first_packet_idx != packet_idx);
+	}
+	tail_idx = priv->echo_skb_tail_idx;
+	if (priv->num_echo_skb < pkts) {
+		int pkts_drop = pkts - priv->num_echo_skb;
+
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Received %u loopback packets but have only %d echo skb. Dropping %d echo skb\n",
+				   pkts, priv->num_echo_skb, pkts_drop);
+		netdev->stats.tx_dropped += pkts_drop;
+		pkts -= pkts_drop;
+	}
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	for (i = 0; i < pkts; i++) {
+		struct sk_buff *skb = priv->can.echo_skb[tail_idx];
+		unsigned int frame_len = 0;
+
+		if (skb)
+			es58x_set_skb_timestamp(netdev, skb, tstamps[i]);
+
+		netdev->stats.tx_bytes += can_get_echo_skb(netdev, tail_idx,
+							   &frame_len);
+		rx_total_frame_len += frame_len;
+
+		es58x_add_skb_idx(priv, &tail_idx, 1);
+	}
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	es58x_add_skb_idx(priv, &priv->echo_skb_tail_idx, pkts);
+	priv->num_echo_skb -= pkts;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	netdev_completed_queue(netdev, pkts, rx_total_frame_len);
+	netdev->stats.tx_packets += pkts;
+
+	priv->err_passive_before_rtx_success = 0;
+	es58x_netif_wake_queue(netdev);
+
+	return ret;
+}
+
+/**
+ * es58x_can_flush_echo_skb() - Reset the loopback FIFO.
+ * @netdev: CAN network device.
+ *
+ * The echo_skb array of struct can_priv will be flushed by
+ * drivers/net/can/dev.c:can_flush_echo_skb(). This function resets
+ * the parameters of the struct es58x_priv of our device and reset the
+ * queue (c.f. BQL).
+ */
+static void es58x_can_flush_echo_skb(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	priv->current_packet_idx = 0;
+	priv->echo_skb_tail_idx = 0;
+	priv->echo_skb_head_idx = 0;
+	priv->num_echo_skb = 0;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	netdev_reset_queue(netdev);
+}
+
+/**
+ * es58x_flush_pending_tx_msg() - Reset the buffer for transmission messages.
+ * @netdev: CAN network device.
+ *
+ * es58x_start_xmit() will queue up to tx_bulk_max messages in
+ * &tx_urb buffer and do a bulk send of all messages in one single URB
+ * (c.f. xmit_more flag). When the device recovers from a bus off
+ * state or when the device stops, the tx_urb buffer might still have
+ * pending messages in it and thus need to be flushed.
+ */
+static void es58x_flush_pending_tx_msg(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	if (priv->tx_urb) {
+		u16 head_idx = priv->echo_skb_head_idx;
+
+		netdev_warn(netdev,
+			    "%s: dropping %d tx_msg that were pending for transmission\n",
+			    __func__, priv->tx_can_msg_cnt);
+		for (i = 0; i < priv->tx_can_msg_cnt; i++) {
+			can_free_echo_skb(netdev, head_idx);
+			es58x_add_skb_idx(priv, &head_idx, 1);
+		}
+		usb_anchor_urb(priv->tx_urb, &priv->es58x_dev->tx_urbs_idle);
+		netdev->stats.tx_dropped += priv->tx_can_msg_cnt;
+
+		atomic_inc(&es58x_dev->tx_urbs_idle_cnt);
+		usb_free_urb(priv->tx_urb);
+	}
+	priv->tx_urb = NULL;
+	priv->tx_total_frame_len = 0;
+	priv->tx_can_msg_cnt = 0;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+}
+
+/**
+ * es58x_tx_ack_msg() - Handle acknowledgment messages.
+ * @netdev: CAN network device.
+ * @tx_free_entries: Number of free entries in the device transmit FIFO.
+ * @rx_cmd_ret_u32: error code as returned by the ES58X device.
+ *
+ * ES58X sends an acknowledgment message after a transmission request
+ * is done. This is mandatory for the ES581.4 but is optional (and
+ * deactivated in this driver) for the ES58X_FD family.
+ *
+ * Under normal circumstances, this function should never throw an
+ * error message.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_tx_ack_msg(struct net_device *netdev, u16 tx_free_entries,
+		     enum es58x_ret_u32 rx_cmd_ret_u32)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+
+	if (tx_free_entries <= priv->es58x_dev->param->tx_bulk_max) {
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "Only %d entries remaining in device queue, echo_skb_max: %d, num_echo_skb: %d, tx_free_entries + num_echo_skb: %d\n",
+				   tx_free_entries, priv->can.echo_skb_max,
+				   priv->num_echo_skb,
+				   tx_free_entries + priv->num_echo_skb);
+		netif_stop_queue(netdev);
+	}
+
+	return es58x_rx_cmd_ret_u32(netdev, ES58X_RET_TYPE_TX_MSG,
+				    rx_cmd_ret_u32);
+}
+
+/**
+ * es58x_rx_can_msg() - Handle a received a CAN message.
+ * @netdev: CAN network device.
+ * @timestamp: Hardware time stamp (only relevant in rx branches).
+ * @data: CAN payload.
+ * @can_id: CAN ID.
+ * @es58x_flags: Please refer to enum es58x_flag.
+ * @dlc: Data Length Code (raw value).
+ *
+ * Fill up a CAN skb and post it.
+ *
+ * This function handles the case where the DLC of a classical CAN
+ * frame is greater than CAN_MAX_DLEN (c.f. the len8_dlc field of
+ * struct can_frame).
+ *
+ * Return: zero on success.
+ */
+int es58x_rx_can_msg(struct net_device *netdev, u64 timestamp, const u8 *data,
+		     canid_t can_id, enum es58x_flag es58x_flags, u8 dlc)
+{
+	struct canfd_frame *cfd;
+	struct can_frame *ccf;
+	struct sk_buff *skb;
+	u8 len;
+	bool is_can_fd = !!(es58x_flags & ES58X_FLAG_FD_DATA);
+
+	if (dlc > CAN_MAX_RAW_DLC) {
+		netdev_err(netdev,
+			   "%s: DLC is %d but maximum should be %d\n",
+			   __func__, dlc, CAN_MAX_RAW_DLC);
+		return -EMSGSIZE;
+	}
+
+	if (is_can_fd) {
+		len = can_fd_dlc2len(dlc);
+		skb = alloc_canfd_skb(netdev, &cfd);
+	} else {
+		len = can_cc_dlc2len(dlc);
+		skb = alloc_can_skb(netdev, &ccf);
+		cfd = (struct canfd_frame *)ccf;
+	}
+
+	if (!skb) {
+		netdev->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+	cfd->can_id = can_id;
+	if (es58x_flags & ES58X_FLAG_EFF)
+		cfd->can_id |= CAN_EFF_FLAG;
+	if (is_can_fd) {
+		cfd->len = len;
+		if (es58x_flags & ES58X_FLAG_FD_BRS)
+			cfd->flags |= CANFD_BRS;
+		if (es58x_flags & ES58X_FLAG_FD_ESI)
+			cfd->flags |= CANFD_ESI;
+	} else {
+		can_frame_set_cc_len(ccf, dlc, es58x_priv(netdev)->can.ctrlmode);
+		if (es58x_flags & ES58X_FLAG_RTR) {
+			ccf->can_id |= CAN_RTR_FLAG;
+			len = 0;
+		}
+	}
+	memcpy(cfd->data, data, len);
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += len;
+
+	es58x_set_skb_timestamp(netdev, skb, timestamp);
+	netif_rx(skb);
+
+	es58x_priv(netdev)->err_passive_before_rtx_success = 0;
+
+	return 0;
+}
+
+/**
+ * es58x_rx_err_msg() - Handle a received CAN event or error message.
+ * @netdev: CAN network device.
+ * @error: Error code.
+ * @event: Event code.
+ * @timestamp: Timestamp received from a ES58X device.
+ *
+ * Handle the errors and events received by the ES58X device, create
+ * a CAN error skb and post it.
+ *
+ * In some rare cases the devices might get stucked alternating between
+ * CAN_STATE_ERROR_PASSIVE and CAN_STATE_ERROR_WARNING. To prevent
+ * this behavior, we force a bus off state if the device goes in
+ * CAN_STATE_ERROR_WARNING for ES58X_MAX_CONSECUTIVE_WARN consecutive
+ * times with no successful transmission or reception in between.
+ *
+ * Once the device is in bus off state, the only way to restart it is
+ * through the drivers/net/can/dev.c:can_restart() function. The
+ * device is technically capable to recover by itself under certain
+ * circumstances, however, allowing self recovery would create
+ * complex race conditions with drivers/net/can/dev.c:can_restart()
+ * and thus was not implemented. To activate automatic restart, please
+ * set the restart-ms parameter (e.g. ip link set can0 type can
+ * restart-ms 100).
+ *
+ * If the bus is really instable, this function would try to send a
+ * lot of log messages. Those are rate limited (i.e. you will see
+ * messages such as "net_ratelimit: XXX callbacks suppressed" in
+ * dmesg).
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_rx_err_msg(struct net_device *netdev, enum es58x_err error,
+		     enum es58x_event event, u64 timestamp)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct can_priv *can = netdev_priv(netdev);
+	struct can_device_stats *can_stats = &can->can_stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev, "%s: %s is down, dropping packet\n",
+				    __func__, netdev->name);
+		netdev->stats.rx_dropped++;
+		return 0;
+	}
+
+	if (error == ES58X_ERR_OK && event == ES58X_EVENT_OK) {
+		netdev_err(netdev, "%s: Both error and event are zero\n",
+			   __func__);
+		return -EINVAL;
+	}
+
+	skb = alloc_can_err_skb(netdev, &cf);
+	if (!skb)
+		return -ENOMEM;
+
+	switch (error) {
+	case ES58X_ERR_OK:	/* 0: No error */
+		break;
+
+	case ES58X_ERR_PROT_STUFF:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error BITSUFF\n");
+		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		break;
+
+	case ES58X_ERR_PROT_FORM:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error FORMAT\n");
+		cf->data[2] |= CAN_ERR_PROT_FORM;
+		break;
+
+	case ES58X_ERR_ACK:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error ACK\n");
+		cf->can_id |= CAN_ERR_ACK;
+		break;
+
+	case ES58X_ERR_PROT_BIT:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error BIT\n");
+		cf->data[2] |= CAN_ERR_PROT_BIT;
+		break;
+
+	case ES58X_ERR_PROT_CRC:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error CRC\n");
+		cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+		break;
+
+	case ES58X_ERR_PROT_BIT1:
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Error: expected a recessive bit but monitored a dominant one\n");
+		cf->data[2] |= CAN_ERR_PROT_BIT1;
+		break;
+
+	case ES58X_ERR_PROT_BIT0:
+		if (net_ratelimit())
+			netdev_dbg(netdev,
+				   "Error expected a dominant bit but monitored a recessive one\n");
+		cf->data[2] |= CAN_ERR_PROT_BIT0;
+		break;
+
+	case ES58X_ERR_PROT_OVERLOAD:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Error OVERLOAD\n");
+		cf->data[2] |= CAN_ERR_PROT_OVERLOAD;
+		break;
+
+	case ES58X_ERR_PROT_UNSPEC:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Unspecified error\n");
+		cf->can_id |= CAN_ERR_PROT;
+		break;
+
+	default:
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "%s: Unspecified error code 0x%04X\n",
+				   __func__, (int)error);
+		cf->can_id |= CAN_ERR_PROT;
+		break;
+	}
+
+	switch (event) {
+	case ES58X_EVENT_OK:	/* 0: No event */
+		break;
+
+	case ES58X_EVENT_CRTL_ACTIVE:
+		if (can->state == CAN_STATE_BUS_OFF) {
+			netdev_err(netdev,
+				   "%s: state transition: BUS OFF -> ACTIVE\n",
+				   __func__);
+		}
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS ACTIVE\n");
+		cf->data[1] |= CAN_ERR_CRTL_ACTIVE;
+		can->state = CAN_STATE_ERROR_ACTIVE;
+		break;
+
+	case ES58X_EVENT_CRTL_PASSIVE:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS PASSIVE\n");
+		/* Either TX or RX error count reached passive state
+		 * but we do not know which. Setting both flags by
+		 * default.
+		 */
+		cf->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
+		cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE;
+		if (can->state < CAN_STATE_BUS_OFF)
+			can->state = CAN_STATE_ERROR_PASSIVE;
+		can_stats->error_passive++;
+		if (priv->err_passive_before_rtx_success < U8_MAX)
+			priv->err_passive_before_rtx_success++;
+		break;
+
+	case ES58X_EVENT_CRTL_WARNING:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS WARNING\n");
+		/* Either TX or RX error count reached warning state
+		 * but we do not know which. Setting both flags by
+		 * default.
+		 */
+		cf->data[1] |= CAN_ERR_CRTL_RX_WARNING;
+		cf->data[1] |= CAN_ERR_CRTL_TX_WARNING;
+		if (can->state < CAN_STATE_BUS_OFF)
+			can->state = CAN_STATE_ERROR_WARNING;
+		can_stats->error_warning++;
+		break;
+
+	case ES58X_EVENT_BUSOFF:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "Event CAN BUS OFF\n");
+		/* Prevent the network device queue for being woke-up
+		 * by another interrupt while we set the bus to off
+		 * status.
+		 */
+		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+		netif_stop_queue(netdev);
+		if (can->state != CAN_STATE_BUS_OFF) {
+			can->state = CAN_STATE_BUS_OFF;
+			can_bus_off(netdev);
+		}
+		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+		cf->can_id |= CAN_ERR_BUSOFF;
+		can_stats->bus_off++;
+		break;
+
+	case ES58X_EVENT_SINGLE_WIRE:
+		if (net_ratelimit())
+			netdev_warn(netdev,
+				    "Lost connection on either CAN high or CAN low\n");
+		/* Lost connection on either CAN high or CAN
+		 * low. Setting both flags by default.
+		 */
+		cf->data[4] |= CAN_ERR_TRX_CANH_NO_WIRE;
+		cf->data[4] |= CAN_ERR_TRX_CANL_NO_WIRE;
+		break;
+
+	default:
+		if (net_ratelimit())
+			netdev_err(netdev,
+				   "%s: Unspecified event code 0x%04X\n",
+				   __func__, (int)event);
+		cf->can_id |= CAN_ERR_CRTL;
+		break;
+	}
+
+	if (cf->data[1])
+		cf->can_id |= CAN_ERR_CRTL;
+	if (cf->data[2] || cf->data[3]) {
+		cf->can_id |= CAN_ERR_PROT;
+		can_stats->bus_error++;
+	}
+	if (cf->data[4])
+		cf->can_id |= CAN_ERR_TRX;
+
+	/* driver/net/can/dev.c:can_restart() takes in account error
+	 * messages in the RX stats. Doing same here for
+	 * consistency.
+	 */
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += cf->can_dlc;
+
+	es58x_set_skb_timestamp(netdev, skb, timestamp);
+	netif_rx(skb);
+
+	if ((event & ES58X_EVENT_CRTL_PASSIVE) &&
+	    priv->err_passive_before_rtx_success ==
+	    ES58X_CONSECUTIVE_ERR_PASSIVE_MAX) {
+		netdev_info(netdev,
+			    "Got %d consecutive warning events with no successful rx or tx. Forcing bus-off\n",
+			    priv->err_passive_before_rtx_success);
+		return es58x_rx_err_msg(netdev, ES58X_ERR_OK,
+					ES58X_EVENT_BUSOFF, timestamp);
+	}
+
+	return 0;
+}
+
+/* Human readable description of the &enum es58x_cmd_ret_type. */
+static const char *const es58x_cmd_ret_desc[] = {
+	"Set bittiming",
+	"Enable channel",
+	"Disable channel",
+	"Transmit message",
+	"Reset rx",
+	"Reset tx",
+	"Device error"
+};
+
+/**
+ * es58x_rx_dev_ret_u8() - Handle return codes received from the
+ *	ES58X device.
+ * @dev: Device, only used for the dev_XXX() print functions.
+ * @cmd_ret_type: Type of the command which triggered the return code.
+ * @rx_dev_ret_u8: error code as returned by the ES58X device.
+ *
+ * Handles the 8 bits return code. Those are specific to the ES581.4
+ * device. The return value will eventually be used by
+ * es58x_handle_urb_cmd() function which will take proper actions in
+ * case of critical issues such and memory errors or bad CRC values.
+ *
+ * In contrast with es58x_rx_cmd_ret_u32(), the network device is
+ * unknown.
+ *
+ * Return: zero on success, return errno when any error occurs.
+ */
+int es58x_rx_dev_ret_u8(struct device *dev,
+			enum es58x_ret_type cmd_ret_type,
+			enum es58x_ret_u8 rx_dev_ret_u8)
+{
+	const char *ret_desc = es58x_cmd_ret_desc[cmd_ret_type];
+
+	compiletime_assert(ARRAY_SIZE(es58x_cmd_ret_desc) ==
+			   ES58X_RET_TYPE_NUM_ENTRIES,
+			   "Size mismatch between es58x_cmd_ret_desc and enum es58x_cmd_ret_type");
+
+	switch (rx_dev_ret_u8) {
+	case ES58X_RET_U8_OK:
+		dev_dbg_ratelimited(dev, "%s: OK\n", ret_desc);
+		break;
+
+	case ES58X_RET_U8_ERR_UNSPECIFIED_FAILURE:
+		dev_err(dev, "%s: unspecified failure\n", ret_desc);
+		break;
+
+	case ES58X_RET_U8_ERR_NO_MEM:
+		dev_err(dev, "%s: device ran out of memory\n", ret_desc);
+		return -ENOMEM;
+
+	case ES58X_RET_U8_ERR_BAD_CRC:
+		dev_err(dev, "%s: CRC of previous command is incorrect\n",
+			ret_desc);
+		return -EIO;
+
+	default:
+		dev_err(dev, "%s: returned unknown value: 0x%02X\n",
+			ret_desc, rx_dev_ret_u8);
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_rx_dev_ret_u32() - Handle return codes received from the
+ *	ES58X device.
+ * @netdev: CAN network device.
+ * @cmd_ret_type: Type of the command which triggered the return code.
+ * @rx_cmd_ret_u32: error code as returned by the ES58X device.
+ *
+ * Handles the 32 bits return code. The return value will eventually
+ * be used by es58x_handle_urb_cmd() function which will take proper
+ * actions in case of critical issues such and memory errors or bad
+ * CRC values.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_rx_cmd_ret_u32(struct net_device *netdev,
+			 enum es58x_ret_type cmd_ret_type,
+			 enum es58x_ret_u32 rx_cmd_ret_u32)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	const char *ret_desc = es58x_cmd_ret_desc[cmd_ret_type];
+
+	switch (rx_cmd_ret_u32) {
+	case ES58X_RET_U32_OK:
+		switch (cmd_ret_type) {
+		case ES58X_RET_TYPE_ENABLE_CHANNEL:
+			es58x_flush_pending_tx_msg(netdev);
+			es58x_can_flush_echo_skb(netdev);
+			priv->err_passive_before_rtx_success = 0;
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+			es58x_netif_wake_queue(netdev);
+			netdev_info(netdev,
+				    "%s (Serial Number %s): CAN%d channel becomes ready\n",
+				    priv->es58x_dev->udev->product,
+				    priv->es58x_dev->udev->serial,
+				    priv->channel_idx + 1);
+			break;
+
+		case ES58X_RET_TYPE_TX_MSG:
+#ifdef VERBOSE_DEBUG
+			if (net_ratelimit())
+				netdev_vdbg(netdev, "%s: OK\n", ret_desc);
+#endif
+			break;
+
+		default:
+			netdev_dbg(netdev, "%s: OK\n", ret_desc);
+			break;
+		}
+		break;
+
+	case ES58X_RET_U32_ERR_UNSPECIFIED_FAILURE:
+		if (cmd_ret_type == ES58X_RET_TYPE_DISABLE_CHANNEL)
+			netdev_dbg(netdev,
+				   "%s: channel is already closed\n", ret_desc);
+		else
+			netdev_err(netdev,
+				   "%s: unspecified failure\n", ret_desc);
+		break;
+
+	case ES58X_RET_U32_ERR_NO_MEM:
+		netdev_err(netdev, "%s: device ran out of memory\n", ret_desc);
+		return -ENOMEM;
+
+	case ES58X_RET_U32_WARN_PARAM_ADJUSTED:
+		netdev_warn(netdev,
+			    "%s: some incompatible parameters have been adjusted\n",
+			    ret_desc);
+		break;
+
+	case ES58X_RET_U32_WARN_TX_MAYBE_REORDER:
+		netdev_warn(netdev,
+			    "%s: TX messages might have been reordered\n",
+			    ret_desc);
+		break;
+
+	case ES58X_RET_U32_ERR_TIMEOUT:
+		netdev_err(netdev, "%s: command timed out\n", ret_desc);
+		break;
+
+	case ES58X_RET_U32_ERR_FIFO_FULL:
+		netdev_warn(netdev, "%s: fifo is full\n", ret_desc);
+		break;
+
+	case ES58X_RET_U32_ERR_BAD_CONFIG:
+		netdev_err(netdev, "%s: bad configuration\n", ret_desc);
+		return -EINVAL;
+
+	case ES58X_RET_U32_ERR_NO_RESOURCE:
+		netdev_err(netdev, "%s: no resource available\n", ret_desc);
+		break;
+
+	default:
+		netdev_err(netdev, "%s returned unknown value: 0x%08X\n",
+			   ret_desc, rx_cmd_ret_u32);
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_increment_rx_errors() - Increment the network devices' error
+ *	count.
+ * @es58x_dev: ES58X device.
+ *
+ * If an error occurs on the early stages on receiving an URB command,
+ * we might not be able to figure out on which network device the
+ * error occurred. In such case, we arbitrarily increment the error
+ * count of all the network devices attached to our ES58X device.
+ */
+static void es58x_increment_rx_errors(struct es58x_device *es58x_dev)
+{
+	int i;
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++)
+		if (es58x_dev->netdev[i])
+			es58x_dev->netdev[i]->stats.rx_errors++;
+}
+
+/**
+ * es58x_handle_urb_cmd() - Handle the URB command
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command received from the ES58X device, might not
+ *	be aligned.
+ *
+ * Sends the URB command to the device specific function. Manages the
+ * errors throwed back by those functions.
+ */
+static void es58x_handle_urb_cmd(struct es58x_device *es58x_dev,
+				 const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es58x_operators *ops = es58x_dev->ops;
+	size_t cmd_len;
+	int i, ret;
+
+	ret = ops->handle_urb_cmd(es58x_dev, urb_cmd);
+	switch (ret) {
+	case 0:		/* OK */
+		return;
+
+	case -ENODEV:
+		dev_err_ratelimited(es58x_dev->dev, "Device is not ready\n");
+		break;
+
+	case -EINVAL:
+	case -EMSGSIZE:
+	case -EBADRQC:
+	case -EBADMSG:
+	case -ECHRNG:
+		cmd_len = es58x_get_urb_cmd_len(es58x_dev,
+						ops->get_msg_len(urb_cmd));
+		dev_err(es58x_dev->dev,
+			"ops->handle_urb_cmd() returned error %pe",
+			ERR_PTR(ret));
+		es58x_print_hex_dump(urb_cmd, cmd_len);
+		break;
+
+	case -EFAULT:
+	case -ENOMEM:
+	case -EIO:
+	default:
+		dev_crit(es58x_dev->dev,
+			 "ops->handle_urb_cmd() returned error %pe, detaching all network devices\n",
+			 ERR_PTR(ret));
+		for (i = 0; i < es58x_dev->num_can_ch; i++)
+			if (es58x_dev->netdev[i])
+				netif_device_detach(es58x_dev->netdev[i]);
+		break;
+	}
+
+	/* Because the urb command could not fully be parsed,
+	 * channel_id is not confirmed. Incrementing rx_errors count
+	 * of all channels.
+	 */
+	es58x_increment_rx_errors(es58x_dev);
+}
+
+/**
+ * es58x_check_rx_urb() - Check the length and format of the URB command.
+ * @es58x_dev: ES58X device.
+ * @urb_cmd: The URB command received from the ES58X device, might not
+ *	be aligned.
+ * @urb_actual_len: The actual length of the URB command.
+ *
+ * Check if the first message of the received urb is valid, that is to
+ * say that both the header and the length are coherent.
+ *
+ * Return:
+ * the length of the first message of the URB on success.
+ *
+ * -ENODATA if the URB command is incomplete (in which case, the URB
+ * command should be buffered and combined with the next URB to try to
+ * reconstitute the URB command).
+ *
+ * -EOVERFLOW if the length is bigger than the maximum expected one.
+ *
+ * -EBADRQC if the start of frame does not match the expected value.
+ */
+static signed int es58x_check_rx_urb(struct es58x_device *es58x_dev,
+				     const union es58x_urb_cmd *urb_cmd,
+				     u32 urb_actual_len)
+{
+	const struct device *dev = es58x_dev->dev;
+	const struct es58x_parameters *param = es58x_dev->param;
+	u16 sof, msg_len;
+	signed int urb_cmd_len, ret;
+
+	if (urb_actual_len < param->urb_cmd_header_len) {
+		dev_vdbg(dev,
+			 "%s: Received %d bytes [%*ph]: header incomplete\n",
+			 __func__, urb_actual_len, urb_actual_len,
+			 urb_cmd->raw_cmd);
+		return -ENODATA;
+	}
+
+	sof = get_unaligned_le16(&urb_cmd->sof);
+	if (sof != param->rx_start_of_frame) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Expected sequence 0x%04X for start of frame but got 0x%04X.\n",
+				    __func__, param->rx_start_of_frame, sof);
+		return -EBADRQC;
+	}
+
+	msg_len = es58x_dev->ops->get_msg_len(urb_cmd);
+	urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	if (urb_cmd_len > param->rx_urb_cmd_max_len) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "%s: Biggest expected size for rx urb_cmd is %u but receive a command of size %d\n",
+				    __func__,
+				    param->rx_urb_cmd_max_len, urb_cmd_len);
+		return -EOVERFLOW;
+	} else if (urb_actual_len < urb_cmd_len) {
+		dev_vdbg(dev, "%s: Received %02d/%02d bytes\n",
+			 __func__, urb_actual_len, urb_cmd_len);
+		return -ENODATA;
+	}
+
+	ret = es58x_check_crc(es58x_dev, urb_cmd, urb_cmd_len);
+	if (ret)
+		return ret;
+
+	return urb_cmd_len;
+}
+
+/**
+ * es58x_flush_cmd_buf() - Reset the buffer for URB commands.
+ * @es58x_dev: ES58X device.
+ */
+static void es58x_flush_cmd_buf(struct es58x_device *es58x_dev)
+{
+	memset(&es58x_dev->rx_cmd_buf, 0, es58x_dev->param->rx_urb_cmd_max_len);
+	es58x_dev->rx_cmd_buf_len = 0;
+}
+
+/**
+ * es58x_copy_to_cmd_buf() - Copy an array to the URB command buffer.
+ * @es58x_dev: ES58X device.
+ * @raw_cmd: the buffer we want to copy.
+ * @raw_cmd_len: length of @raw_cmd.
+ *
+ * Concatenates @raw_cmd_len bytes of @raw_cmd to the end of the URB
+ * command buffer.
+ *
+ * Return: zero on success, -EMSGSIZE if not enough space is available
+ * to do the copy.
+ */
+static int es58x_copy_to_cmd_buf(struct es58x_device *es58x_dev,
+				 u8 *raw_cmd, int raw_cmd_len)
+{
+	if (es58x_dev->rx_cmd_buf_len + raw_cmd_len >
+	    es58x_dev->param->rx_urb_cmd_max_len)
+		return -EMSGSIZE;
+
+	memcpy(&es58x_dev->rx_cmd_buf.raw_cmd[es58x_dev->rx_cmd_buf_len],
+	       raw_cmd, raw_cmd_len);
+	es58x_dev->rx_cmd_buf_len += raw_cmd_len;
+
+	return 0;
+}
+
+/**
+ * es58x_split_urb_try_recovery() - Try to recover bad URB sequences.
+ * @es58x_dev: ES58X device.
+ * @raw_cmd: pointer to the buffer we want to copy.
+ * @raw_cmd_len: length of @raw_cmd.
+ *
+ * Under some rare conditions, we might get incorrect URBs from the
+ * device. From our observations, one of the valid URB gets replaced
+ * by one from the past. The full root cause is not identified.
+ *
+ * This function looks for the next start of frame in the urb buffer
+ * in order to try to recover.
+ *
+ * Such behavior was not observed on the devices of the ES58X FD
+ * family and only seems to impact the ES581.4.
+ *
+ * Return: the number of bytes dropped on success, -EBADMSG if recovery failed.
+ */
+static int es58x_split_urb_try_recovery(struct es58x_device *es58x_dev,
+					u8 *raw_cmd, size_t raw_cmd_len)
+{
+	union es58x_urb_cmd *urb_cmd;
+	signed int urb_cmd_len;
+	u16 sof;
+	int dropped_bytes = 0;
+
+	es58x_increment_rx_errors(es58x_dev);
+
+	while (raw_cmd_len > sizeof(sof)) {
+		urb_cmd = (union es58x_urb_cmd *)raw_cmd;
+		sof = get_unaligned_le16(&urb_cmd->sof);
+
+		if (sof == es58x_dev->param->rx_start_of_frame) {
+			urb_cmd_len = es58x_check_rx_urb(es58x_dev,
+							 urb_cmd, raw_cmd_len);
+			if ((urb_cmd_len == -ENODATA) || urb_cmd_len > 0) {
+				dev_info_ratelimited(es58x_dev->dev,
+						     "Recovery successful! Dropped %d bytes (urb_cmd_len: %d)\n",
+						     dropped_bytes,
+						     urb_cmd_len);
+				return dropped_bytes;
+			}
+		}
+		raw_cmd++;
+		raw_cmd_len--;
+		dropped_bytes++;
+	}
+
+	dev_warn_ratelimited(es58x_dev->dev, "%s: Recovery failed\n", __func__);
+	return -EBADMSG;
+}
+
+/**
+ * es58x_handle_incomplete_cmd() - Reconstitute an URB command from
+ *	different URB pieces.
+ * @es58x_dev: ES58X device.
+ * @urb: last urb buffer received.
+ *
+ * The device might split the URB commands in an arbitrary amount of
+ * pieces. This function concatenates those in an URB buffer until a
+ * full URB command is reconstituted and consume it.
+ *
+ * Return:
+ * number of bytes consumed from @urb if successful.
+ *
+ * -ENODATA if the URB command is still incomplete.
+ *
+ * -EBADMSG if the URB command is incorrect.
+ */
+static signed int es58x_handle_incomplete_cmd(struct es58x_device *es58x_dev,
+					      struct urb *urb)
+{
+	size_t cpy_len;
+	signed int urb_cmd_len, tmp_cmd_buf_len, ret;
+
+	tmp_cmd_buf_len = es58x_dev->rx_cmd_buf_len;
+	cpy_len = min_t(int, es58x_dev->param->rx_urb_cmd_max_len -
+			es58x_dev->rx_cmd_buf_len, urb->actual_length);
+	ret = es58x_copy_to_cmd_buf(es58x_dev, urb->transfer_buffer, cpy_len);
+	if (ret < 0)
+		return ret;
+
+	urb_cmd_len = es58x_check_rx_urb(es58x_dev, &es58x_dev->rx_cmd_buf,
+					 es58x_dev->rx_cmd_buf_len);
+	if (urb_cmd_len == -ENODATA) {
+		return -ENODATA;
+	} else if (urb_cmd_len < 0) {
+		dev_err_ratelimited(es58x_dev->dev,
+				    "Could not reconstitute incomplete command from previous URB, dropping %d bytes\n",
+				    tmp_cmd_buf_len + urb->actual_length);
+		dev_err_ratelimited(es58x_dev->dev,
+				    "Error code: %pe, es58x_dev->rx_cmd_buf_len: %d, urb->actual_length: %u\n",
+				    ERR_PTR(urb_cmd_len),
+				    tmp_cmd_buf_len, urb->actual_length);
+		es58x_print_hex_dump(&es58x_dev->rx_cmd_buf, tmp_cmd_buf_len);
+		es58x_print_hex_dump(urb->transfer_buffer, urb->actual_length);
+		return urb->actual_length;
+	}
+
+	es58x_handle_urb_cmd(es58x_dev, &es58x_dev->rx_cmd_buf);
+	return urb_cmd_len - tmp_cmd_buf_len;	/* consumed length */
+}
+
+/**
+ * es58x_split_urb() - Cut the received URB in individual URB commands.
+ * @es58x_dev: ES58X device.
+ * @urb: last urb buffer received.
+ *
+ * The device might send urb in bulk format (i.e. several URB commands
+ * concatenated together). This function will split all the commands
+ * contained in the urb.
+ *
+ * Return:
+ * number of bytes consumed from @urb if successful.
+ *
+ * -ENODATA if the URB command is still incomplete.
+ *
+ * -EBADMSG if the URB command is incorrect.
+ */
+static signed int es58x_split_urb(struct es58x_device *es58x_dev,
+				  struct urb *urb)
+{
+	const u8 es58x_is_alive = 0x11;
+	union es58x_urb_cmd *urb_cmd;
+	u8 *raw_cmd = urb->transfer_buffer;
+	ssize_t raw_cmd_len = urb->actual_length;
+	int ret;
+
+	if (es58x_dev->rx_cmd_buf_len != 0) {
+		ret = es58x_handle_incomplete_cmd(es58x_dev, urb);
+		if (ret != -ENODATA)
+			es58x_flush_cmd_buf(es58x_dev);
+		if (ret < 0)
+			return ret;
+
+		raw_cmd += ret;
+		raw_cmd_len -= ret;
+	}
+
+	while (raw_cmd_len > 0) {
+		if (raw_cmd[0] == es58x_is_alive) {
+			raw_cmd++;
+			raw_cmd_len--;
+			continue;
+		}
+		urb_cmd = (union es58x_urb_cmd *)raw_cmd;
+		ret = es58x_check_rx_urb(es58x_dev, urb_cmd, raw_cmd_len);
+		if (ret > 0) {
+			es58x_handle_urb_cmd(es58x_dev, urb_cmd);
+		} else if (ret == -ENODATA) {
+			es58x_copy_to_cmd_buf(es58x_dev, raw_cmd, raw_cmd_len);
+			return -ENODATA;
+		} else if (ret < 0) {
+			ret = es58x_split_urb_try_recovery(es58x_dev, raw_cmd,
+							   raw_cmd_len);
+			if (ret < 0)
+				return ret;
+		}
+		raw_cmd += ret;
+		raw_cmd_len -= ret;
+	}
+
+	return 0;
+}
+
+/**
+ * es58x_read_bulk_callback() - Callback for reading data from device.
+ * @urb: last urb buffer received.
+ *
+ * This function gets eventually called each time an URB is received
+ * from the ES58X device.
+ *
+ * Checks urb status, calls read function and resubmits urb read
+ * operation.
+ */
+static void es58x_read_bulk_callback(struct urb *urb)
+{
+	struct es58x_device *es58x_dev = urb->context;
+	const struct device *dev = es58x_dev->dev;
+	int i, ret;
+
+	switch (urb->status) {
+	case 0:		/* success */
+		break;
+
+	case -EOVERFLOW:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		es58x_print_hex_dump_debug(urb->transfer_buffer,
+					   urb->transfer_buffer_length);
+		goto resubmit_urb;
+
+	case -EPROTO:
+		dev_warn_ratelimited(dev, "%s: error %pe. Device unplugged?\n",
+				     __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	case -ENOENT:
+	case -EPIPE:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	case -ESHUTDOWN:
+		dev_dbg_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto free_urb;
+
+	default:
+		dev_err_ratelimited(dev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		goto resubmit_urb;
+	}
+
+	ret = es58x_split_urb(es58x_dev, urb);
+	if ((ret != -ENODATA) && ret < 0) {
+		dev_err(es58x_dev->dev, "es58x_split_urb() returned error %pe",
+			ERR_PTR(ret));
+		es58x_print_hex_dump_debug(urb->transfer_buffer,
+					   urb->actual_length);
+
+		/* Because the urb command could not be parsed,
+		 * channel_id is not confirmed. Incrementing rx_errors
+		 * count of all channels.
+		 */
+		es58x_increment_rx_errors(es58x_dev);
+	}
+
+ resubmit_urb:
+	usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->rx_pipe,
+			  urb->transfer_buffer, urb->transfer_buffer_length,
+			  es58x_read_bulk_callback, es58x_dev);
+
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret == -ENODEV) {
+		for (i = 0; i < es58x_dev->num_can_ch; i++)
+			if (es58x_dev->netdev[i])
+				netif_device_detach(es58x_dev->netdev[i]);
+	} else if (ret)
+		dev_err_ratelimited(dev,
+				    "Failed resubmitting read bulk urb: %pe\n",
+				    ERR_PTR(ret));
+	return;
+
+ free_urb:
+	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+}
+
+/**
+ * es58x_write_bulk_callback() - Callback after writing data to the device.
+ * @urb: urb buffer which was previously submitted.
+ *
+ * This function gets eventually called each time an URB was sent to
+ * the ES58X device.
+ *
+ * Puts the @urb back to the urbs idle anchor and tries to restart the
+ * network queue.
+ */
+static void es58x_write_bulk_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+
+	switch (urb->status) {
+	case 0:		/* success */
+		break;
+
+	case -EOVERFLOW:
+		if (net_ratelimit())
+			netdev_err(netdev, "%s: error %pe\n",
+				   __func__, ERR_PTR(urb->status));
+		es58x_print_hex_dump(urb->transfer_buffer,
+				     urb->transfer_buffer_length);
+		break;
+
+	case -ENOENT:
+		if (net_ratelimit())
+			netdev_dbg(netdev, "%s: error %pe\n",
+				   __func__, ERR_PTR(urb->status));
+		usb_free_coherent(urb->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+		return;
+
+	default:
+		if (net_ratelimit())
+			netdev_info(netdev, "%s: error %pe\n",
+				    __func__, ERR_PTR(urb->status));
+		break;
+	}
+
+	usb_anchor_urb(urb, &es58x_dev->tx_urbs_idle);
+	/* Wake the queue if it was stopped because of exhaustion of
+	 * urb resources.
+	 */
+	if (atomic_inc_return(&es58x_dev->tx_urbs_idle_cnt) ==
+	    es58x_dev->num_can_ch)
+		es58x_netif_wake_all_queues(es58x_dev);
+}
+
+/**
+ * es58x_alloc_urb() - Allocate memory for an URB and its transfer
+ *	buffer.
+ * @es58x_dev: ES58X device.
+ * @urb: URB to be allocated.
+ * @buf: used to return DMA address of buffer.
+ * @buf_len: requested buffer size.
+ * @mem_flags: affect whether allocation may block.
+ *
+ * Allocates an URB and its @transfer_buffer and set its @transfer_dma
+ * address.
+ *
+ * This function is used at start-up to allocate all of our TX and RX
+ * URBs at once (in order to avoid numerous memory allocations during
+ * run time) and might be used during run time under extremely rare
+ * conditions by @es58x_get_tx_urb() (c.f. comments of this function).
+ *
+ * Return: zero on success, -ENOMEM if no memory is available.
+ */
+static int es58x_alloc_urb(struct es58x_device *es58x_dev, struct urb **urb,
+			   u8 **buf, size_t buf_len, gfp_t mem_flags)
+{
+	*urb = usb_alloc_urb(0, mem_flags);
+	if (!*urb) {
+		dev_err(es58x_dev->dev, "No memory left for URBs\n");
+		return -ENOMEM;
+	}
+
+	*buf = usb_alloc_coherent(es58x_dev->udev, buf_len,
+				  mem_flags, &(*urb)->transfer_dma);
+	if (!*buf) {
+		dev_err(es58x_dev->dev, "No memory left for USB buffer\n");
+		usb_free_urb(*urb);
+		return -ENOMEM;
+	}
+
+	(*urb)->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	return 0;
+}
+
+/**
+ * es58x_get_tx_urb() - Get an URB for transmission.
+ * @netdev: CAN network device.
+ *
+ * Gets an URB from the idle urbs anchor and stop all network devices'
+ * queue if the idle urbs anchor is nearly empty.
+ *
+ * If the URB anchor is empty, allocates an new URB.
+ *
+ * Under normal circumstances, the network device stop/wake
+ * management should prevent any further request for memory
+ * allocations to occur when trying to send a message.
+ *
+ * Yet, new URB memory allocation might occur after a restart from bus
+ * off status when @es58x_set_mode() tries to disable and re-enable
+ * the device. This would only occur if no idle URBs are available at
+ * the moment (which is highly improbable because
+ * @es58x_write_bulk_callback() should have returned the URBs to the
+ * idle urbs anchor by that point).
+ *
+ * Return: a pointer to an URB on success, NULL if no memory is
+ * available.
+ */
+static struct urb *es58x_get_tx_urb(struct net_device *netdev)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	struct urb *urb;
+	unsigned long flags;
+
+	urb = usb_get_from_anchor(&es58x_dev->tx_urbs_idle);
+
+	if (!urb) {
+		size_t tx_buf_len;
+		u8 *buf;
+
+		netdev_warn(netdev,
+			    "%s: Idle TX URB anchor is empty. Allocating an extra URB\n",
+			    __func__);
+		tx_buf_len = es58x_dev->param->tx_urb_cmd_max_len;
+		if (es58x_alloc_urb(es58x_dev, &urb, &buf, tx_buf_len,
+				    GFP_ATOMIC))
+			urb = NULL;
+		else
+			usb_fill_bulk_urb(urb, es58x_dev->udev,
+					  es58x_dev->tx_pipe, buf, tx_buf_len,
+					  NULL, NULL);
+	} else {
+		spin_lock_irqsave(&es58x_dev->tx_urbs_idle.lock, flags);
+		if (atomic_dec_return(&es58x_dev->tx_urbs_idle_cnt) <
+		    es58x_dev->num_can_ch)
+			es58x_netif_stop_all_queues(es58x_dev);
+		spin_unlock_irqrestore(&es58x_dev->tx_urbs_idle.lock, flags);
+	}
+
+	return urb;
+}
+
+/**
+ * es58x_submit_urb() - Send data to the device.
+ * @es58x_dev: ES58X device.
+ * @urb: URB to be sent.
+ * @netdev: CAN network device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_submit_urb(struct es58x_device *es58x_dev, struct urb *urb,
+			    struct net_device *netdev)
+{
+	int ret;
+
+	es58x_set_crc(urb->transfer_buffer, urb->transfer_buffer_length);
+	usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->tx_pipe,
+			  urb->transfer_buffer, urb->transfer_buffer_length,
+			  es58x_write_bulk_callback, netdev);
+	usb_anchor_urb(urb, &es58x_dev->tx_urbs_busy);
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret) {
+		netdev_err(netdev, "%s: USB send urb failure: %pe\n",
+			   __func__, ERR_PTR(ret));
+		usb_unanchor_urb(urb);
+		usb_free_coherent(urb->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+	}
+	usb_free_urb(urb);
+
+	return ret;
+}
+
+/**
+ * es58x_send_msg() - Prepare an URB and submit it.
+ * @es58x_dev: ES58X device.
+ * @cmd_type: Command type.
+ * @cmd_id: Command ID.
+ * @msg: ES58X message to be sent.
+ * @msg_len: Length of @msg.
+ * @channel_idx: Index of the network device.
+ *
+ * Creates an URB command from a given message, sets the header and the
+ * CRC and then submits it.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+int es58x_send_msg(struct es58x_device *es58x_dev, u8 cmd_type, u8 cmd_id,
+		   const void *msg, u16 msg_len, int channel_idx)
+{
+	struct net_device *netdev;
+	union es58x_urb_cmd *urb_cmd;
+	struct urb *urb;
+	int urb_cmd_len;
+
+	if (channel_idx == ES58X_CHANNEL_IDX_NA)
+		netdev = es58x_dev->netdev[0];	/* Default to first channel */
+	else
+		netdev = es58x_dev->netdev[channel_idx];
+
+	urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	if (urb_cmd_len > es58x_dev->param->tx_urb_cmd_max_len)
+		return -EOVERFLOW;
+
+	urb = es58x_get_tx_urb(netdev);
+	if (!urb)
+		return -EBUSY;
+
+	urb_cmd = urb->transfer_buffer;
+	es58x_dev->ops->fill_urb_header(urb_cmd, cmd_type, cmd_id,
+					channel_idx, msg_len);
+	memcpy(&urb_cmd->raw_cmd[es58x_dev->param->urb_cmd_header_len],
+	       msg, msg_len);
+	urb->transfer_buffer_length = urb_cmd_len;
+
+	return es58x_submit_urb(es58x_dev, urb, netdev);
+}
+
+/**
+ * es58x_start() - Start USB device.
+ * @es58x_dev: ES58X device.
+ *
+ * Allocate URBs for transmission and reception and put them in their
+ * respective anchors.
+ *
+ * This function took a lot of inspiration from the other drivers in
+ * drivers/net/can/usb.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_start(struct es58x_device *es58x_dev)
+{
+	const struct device *dev = es58x_dev->dev;
+	const struct es58x_parameters *param = es58x_dev->param;
+	size_t rx_buf_len, tx_buf_len;
+	struct urb *urb;
+	u8 *buf;
+	int i;
+	int ret = -EINVAL;
+
+	rx_buf_len = es58x_dev->rx_max_packet_size;
+	dev_dbg(dev, "%s: Allocation %d rx URBs each of size %zu\n", __func__,
+		param->rx_urb_max, rx_buf_len);
+
+	for (i = 0; i < param->rx_urb_max; i++) {
+		ret = es58x_alloc_urb(es58x_dev, &urb, &buf, rx_buf_len,
+				      GFP_KERNEL);
+		if (ret)
+			break;
+
+		usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->rx_pipe,
+				  buf, rx_buf_len, es58x_read_bulk_callback,
+				  es58x_dev);
+		usb_anchor_urb(urb, &es58x_dev->rx_urbs);
+
+		ret = usb_submit_urb(urb, GFP_KERNEL);
+		if (ret) {
+			usb_unanchor_urb(urb);
+			usb_free_coherent(es58x_dev->udev, rx_buf_len,
+					  buf, urb->transfer_dma);
+			usb_free_urb(urb);
+			break;
+		}
+		usb_free_urb(urb);
+	}
+
+	if (i == 0) {
+		dev_err(dev, "%s: Could not setup any rx URBs\n", __func__);
+		return ret;
+	} else if (i < param->rx_urb_max) {
+		dev_warn(dev,
+			 "%s: Could only allocate %d on %d URBs. Rx performance may be slow\n",
+			 __func__, i, param->rx_urb_max);
+	}
+
+	tx_buf_len = es58x_dev->param->tx_urb_cmd_max_len;
+	dev_dbg(dev, "%s: Allocation %d tx URBs each of size %zu\n", __func__,
+		param->tx_urb_max, tx_buf_len);
+
+	for (i = 0; i < param->tx_urb_max; i++) {
+		ret = es58x_alloc_urb(es58x_dev, &urb, &buf, tx_buf_len,
+				      GFP_KERNEL);
+		if (ret)
+			break;
+
+		usb_fill_bulk_urb(urb, es58x_dev->udev, es58x_dev->tx_pipe,
+				  buf, tx_buf_len, NULL, NULL);
+		usb_anchor_urb(urb, &es58x_dev->tx_urbs_idle);
+		usb_free_urb(urb);
+	}
+
+	if (i == 0) {
+		dev_err(dev, "%s: Could not setup any tx URBs\n", __func__);
+		return ret;
+	} else if (i < param->tx_urb_max) {
+		dev_warn(dev,
+			 "%s: Could only allocate %d on %d URBs. Tx performance may be slow\n",
+			 __func__, i, param->tx_urb_max);
+	}
+	atomic_set(&es58x_dev->tx_urbs_idle_cnt, i);
+
+	return ret;
+}
+
+/**
+ * es58x_enable_channel() - Enable the network device.
+ * @netdev: CAN network device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_enable_channel(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	int ret;
+
+	ret = es58x_dev->ops->enable_channel(es58x_dev, priv->channel_idx);
+	if (ret)
+		netdev_err(netdev, "%s: Could not enable the channel: %pe\n",
+			   __func__, ERR_PTR(ret));
+
+	return ret;
+}
+
+/**
+ * es58x_open() - Open and start network device.
+ * @netdev: CAN network device.
+ *
+ * Called when the network transitions to the up state.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_open(struct net_device *netdev)
+{
+	int ret;
+
+	ret = open_candev(netdev);
+	if (ret)
+		return ret;
+
+	ret = es58x_enable_channel(netdev);
+	if (ret)
+		return ret;
+
+	netif_start_queue(netdev);
+
+	return ret;
+}
+
+/**
+ * es58x_stop() - Disable the network device.
+ * @netdev: CAN network device.
+ *
+ * Called when the network transitions to the down state.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_stop(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	netif_stop_queue(netdev);
+	priv->can.state = CAN_STATE_STOPPED;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+	es58x_can_flush_echo_skb(netdev);
+	close_candev(netdev);
+
+	es58x_flush_pending_tx_msg(netdev);
+
+	return 0;
+}
+
+/**
+ * es58x_xmit_commit() - Send the bulk urb.
+ * @netdev: CAN network device.
+ *
+ * Update the loopback FIFO and do a bulk send.
+ *
+ * Each loopback skb should be put individually with
+ * can_put_echo_skb(). This function should be called only once by
+ * bulk transmission.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_xmit_commit(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	unsigned long flags;
+	unsigned int pkts = priv->tx_can_msg_cnt;
+	int ret;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	if (!es58x_is_can_state_active(netdev)) {
+		netdev_warn(netdev,
+			    "%s: Device turned to CAN state %d while preparing to send. Aborting transmission\n",
+			    __func__, priv->can.state);
+		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+		return -ENETDOWN;
+	}
+	priv->num_echo_skb += pkts;
+	priv->current_packet_idx += pkts;
+	es58x_add_skb_idx(priv, &priv->echo_skb_head_idx, pkts);
+	if (priv->num_echo_skb >= es58x_echo_skb_stop_threshold(priv))
+		netif_stop_queue(netdev);
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	netdev_sent_queue(netdev, priv->tx_total_frame_len);
+	ret = es58x_submit_urb(priv->es58x_dev, priv->tx_urb, netdev);
+	if (ret) {
+		netdev_warn(netdev,
+			    "%s: es58x_submit_urb returned failed: %pe priv->num_echo_skb = %u\n",
+			    __func__, ERR_PTR(ret), priv->num_echo_skb);
+		netdev_completed_queue(netdev, pkts, priv->tx_total_frame_len);
+		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+		priv->num_echo_skb -= pkts;
+		priv->current_packet_idx -= pkts;
+		es58x_add_skb_idx(priv, &priv->echo_skb_head_idx,
+				  priv->can.echo_skb_max - pkts);
+		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+	}
+	priv->tx_urb = NULL;
+
+	return ret;
+}
+
+/**
+ * es58x_start_xmit() - Transmit an skb.
+ * @skb: socket buffer of a CAN message.
+ * @netdev: CAN network device.
+ *
+ * Called when a packet needs to be transmitted.
+ *
+ * This function relies on Byte Queue Limits (BQL). The main benefit
+ * it to increase the throughput by allowing bulk transfers
+ * (c.f. xmit_more flag).
+ *
+ * Queues up to tx_bulk_max messages in &tx_urb buffer and does
+ * a bulk send of all messages in one single URB.
+ *
+ * Return:
+ * NETDEV_TX_OK if we could manage the @skb (either transmit it or
+ * drop it)
+ *
+ * NETDEV_TX_BUSY if the device is busy (this is a bug, the network
+ * device stop/wake management should prevent this return code to
+ * occur).
+ */
+static netdev_tx_t es58x_start_xmit(struct sk_buff *skb,
+				    struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	unsigned int packet_idx, tx_msg_threshold, frame_len;
+	u16 skb_idx;
+	u8 channel_idx = priv->channel_idx;
+	int ret;
+
+	if (((struct can_frame *)skb->data)->can_id & CAN_ERR_FLAG) {
+		netdev_info(netdev,
+			    "%s: CAN_ERR_FLAG is set but device does not support sending error frames. Dropping message\n",
+			    __func__);
+		dev_kfree_skb(skb);
+		netdev->stats.tx_dropped++;
+		if (priv->tx_urb && !netdev_xmit_more()) {
+			ret = es58x_xmit_commit(netdev);
+			if (ret)
+				goto xmit_failure;
+		}
+		return NETDEV_TX_OK;
+	}
+
+	if (!priv->tx_urb) {
+		priv->tx_urb = es58x_get_tx_urb(netdev);
+		if (!priv->tx_urb)
+			return NETDEV_TX_BUSY;
+		memset(priv->tx_urb->transfer_buffer, 0,
+		       es58x_dev->param->tx_urb_cmd_max_len);
+		priv->tx_urb->transfer_buffer_length =
+		    es58x_dev->param->urb_cmd_header_len;
+		priv->tx_total_frame_len = 0;
+		priv->tx_can_msg_cnt = 0;
+		priv->tx_can_msg_is_fd = can_is_canfd_skb(skb);
+	} else if (priv->tx_can_msg_is_fd != can_is_canfd_skb(skb)) {
+		/* Can not do bulk send with mixed CAN and CAN FD frames. */
+		ret = es58x_xmit_commit(netdev);
+		if (ret)
+			goto drop_skb;
+		return es58x_start_xmit(skb, netdev);
+	}
+
+	packet_idx = priv->current_packet_idx + priv->tx_can_msg_cnt;
+	ret = es58x_dev->ops->tx_can_msg(priv, channel_idx,
+					 packet_idx, skb,
+					 priv->tx_urb->transfer_buffer,
+					 &priv->tx_urb->transfer_buffer_length);
+	if (ret)
+		goto drop_skb;
+
+	skb_idx = priv->echo_skb_head_idx;
+	es58x_add_skb_idx(priv, &skb_idx, priv->tx_can_msg_cnt);
+	frame_len = can_skb_get_frame_len(skb);
+	priv->tx_total_frame_len += frame_len;
+	ret = can_put_echo_skb(skb, netdev, skb_idx, frame_len);
+	if (ret)
+		goto xmit_failure;
+	priv->tx_can_msg_cnt++;
+
+	tx_msg_threshold = min_t(unsigned int,
+				 es58x_dev->param->tx_bulk_max,
+				 priv->can.echo_skb_max - priv->num_echo_skb);
+	if (!netdev_xmit_more() || priv->tx_can_msg_cnt >= tx_msg_threshold) {
+		ret = es58x_xmit_commit(netdev);
+		if (ret)
+			goto xmit_failure;
+	}
+
+	return NETDEV_TX_OK;
+
+ drop_skb:
+	dev_kfree_skb(skb);
+	netdev->stats.tx_dropped++;
+ xmit_failure:
+	netdev->stats.tx_errors++;
+	es58x_flush_pending_tx_msg(netdev);
+	netdev_err(netdev, "%s: send message failure: %pe\n",
+		   __func__, ERR_PTR(ret));
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops es58x_netdev_ops = {
+	.ndo_open = es58x_open,
+	.ndo_stop = es58x_stop,
+	.ndo_start_xmit = es58x_start_xmit
+};
+
+/**
+ * es58x_set_bittiming() - Configure all the nominal bit timing
+ *	parameters.
+ * @netdev: CAN network device.
+ *
+ * Only relevant for ES581.4 (the ES58X FD family sets the bittiming
+ * parameters at the same time as the channel gets enabled).
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_set_bittiming(struct net_device *netdev)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	int ret;
+
+	/* Make sure that channel is closed before sending configuration. */
+	ret = es58x_dev->ops->disable_channel(es58x_dev, priv->channel_idx);
+	if (ret)
+		netdev_err(netdev, "%s: Could not disable the channel: %pe\n",
+			   __func__, ERR_PTR(ret));
+	ret = es58x_dev->ops->set_bittiming(es58x_dev, priv->channel_idx);
+	if (ret)
+		netdev_err(netdev, "%s: Could not set bittiming: %pe\n",
+			   __func__, ERR_PTR(ret));
+
+	return ret;
+}
+
+/**
+ * es58x_set_data_bittiming() - Configure all the data bit timing parameters.
+ * @netdev: CAN network device.
+ *
+ * Dummy function: ES58X FD family sets the bittiming
+ * parameters at the same time as the channel gets enabled.
+ *
+ * Return: zero.
+ */
+static int es58x_set_data_bittiming(struct net_device *netdev)
+{
+	return 0;
+}
+
+/**
+ * es58x_reset() - Reset one channel of the device.
+ * @netdev: CAN network device.
+ *
+ * Race conditions might appear when trying to use the reset_rx()
+ * and reset_tx() methods (e.g. loopback packets might remain in the
+ * queue causing some use after free issues in
+ * es58x_can_get_echo_skb()). Disabling and reenabling the channel is
+ * safer.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_reset(struct net_device *netdev)
+{
+	int ret = 0;
+
+	if (es58x_is_can_state_active(netdev))
+		es58x_priv(netdev)->can.do_set_mode(netdev, CAN_MODE_STOP);
+	WARN_ON(!netif_queue_stopped(netdev));
+
+	ret = es58x_set_bittiming(netdev);
+	if (ret)
+		goto failure;
+	ret = es58x_enable_channel(netdev);
+	if (ret)
+		goto failure;
+
+	return ret;
+
+ failure:
+	netdev_err(netdev, "%s: reset failure: %pe\n", __func__, ERR_PTR(ret));
+	return ret;
+}
+
+/**
+ * es58x_set_mode() - Change network device mode.
+ * @netdev: CAN network device.
+ * @mode: either %CAN_MODE_START, %CAN_MODE_STOP or %CAN_MODE_SLEEP
+ *
+ * This function is used by drivers/net/can/dev.c:can_restart() to
+ * recover from a bus off state. Thus only the only value expected for
+ * @mode is %CAN_MODE_START. None the less, other modes were
+ * implemented as well.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct can_priv *can = netdev_priv(netdev);
+	unsigned long flags;
+
+	netdev_dbg(netdev, "%s: Switching to can_mode %d\n", __func__, mode);
+
+	switch (mode) {
+	case CAN_MODE_START:
+		switch (can->state) {
+		case CAN_STATE_BUS_OFF:
+			return es58x_reset(netdev);
+
+		case CAN_STATE_STOPPED:
+		case CAN_STATE_SLEEPING:
+			es58x_netif_wake_queue(netdev);
+			can->state = CAN_STATE_ERROR_ACTIVE;
+			return 0;
+
+		case CAN_STATE_ERROR_ACTIVE:
+		case CAN_STATE_ERROR_WARNING:
+		case CAN_STATE_ERROR_PASSIVE:
+		default:
+			return 0;
+		}
+
+	case CAN_MODE_STOP:
+	case CAN_MODE_SLEEP:
+		spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+		netif_stop_queue(netdev);
+		can->state = (mode == CAN_MODE_STOP) ?
+		    CAN_STATE_STOPPED : CAN_STATE_SLEEPING;
+		spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+		return 0;
+
+	default:
+		netdev_err(netdev, "%s: Invalid can_mode value: %d\n",
+			   __func__, mode);
+		return -EOPNOTSUPP;
+	}
+}
+
+/**
+ * es58x_init_priv() - Initialize private parameters.
+ * @es58x_dev: ES58X device.
+ * @priv: ES58X private parameters related to the network device.
+ * @channel_idx: Index of the network device.
+ */
+static void es58x_init_priv(struct es58x_device *es58x_dev,
+			    struct es58x_priv *priv, int channel_idx)
+{
+	const struct es58x_parameters *param = es58x_dev->param;
+	struct can_priv *can = &priv->can;
+
+	priv->es58x_dev = es58x_dev;
+	priv->channel_idx = channel_idx;
+	priv->tx_urb = NULL;
+	priv->tx_can_msg_cnt = 0;
+	spin_lock_init(&priv->echo_skb_spinlock);
+
+	can->bittiming_const = param->bittiming_const;
+	can->do_set_bittiming = es58x_set_bittiming;
+	if (param->ctrlmode_supported & CAN_CTRLMODE_FD) {
+		can->data_bittiming_const = param->data_bittiming_const;
+		can->do_set_data_bittiming = es58x_set_data_bittiming;
+	}
+	can->bitrate_max = param->bitrate_max;
+	can->clock = param->clock;
+
+	can->state = CAN_STATE_STOPPED;
+
+	/* Hardware loopback is always enabled, regardless of the
+	 * value of can.ctrlmode & CAN_CTRLMODE_LOOPBACK.
+	 */
+	can->ctrlmode_supported = param->ctrlmode_supported;
+	can->do_get_berr_counter = NULL;	/* Not supported */
+
+	can->do_set_mode = es58x_set_mode;
+}
+
+/**
+ * es58x_init_netdev() - Initialize the network device.
+ * @es58x_dev: ES58X device.
+ * @channel_idx: Index of the network device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx)
+{
+	struct net_device *netdev;
+	struct device *dev = es58x_dev->dev;
+	int ret;
+
+	netdev = alloc_candev(sizeof(struct es58x_priv),
+			      es58x_dev->param->echo_skb_max);
+	if (!netdev) {
+		dev_err(dev, "Could not allocate candev\n");
+		return -ENOMEM;
+	}
+	SET_NETDEV_DEV(netdev, dev);
+	es58x_dev->netdev[channel_idx] = netdev;
+	es58x_init_priv(es58x_dev, es58x_priv(netdev), channel_idx);
+
+	netdev->netdev_ops = &es58x_netdev_ops;
+	netdev->flags |= IFF_ECHO;	/* we support local echo */
+
+	ret = register_candev(netdev);
+	if (ret)
+		return ret;
+	netdev_dbg(netdev, "%s: Registered channel %s\n",
+		   es58x_dev->udev->product, netdev->name);
+
+#ifdef CONFIG_BQL
+	netdev_get_tx_queue(netdev, 0)->dql.min_limit =
+	    es58x_dev->param->dql_limit_min;
+#endif
+
+	return ret;
+}
+
+/**
+ * es58x_get_product_info() - Get the product information and print them.
+ * @es58x_dev: ES58X device.
+ *
+ * Do a synchronous call to get the product information.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_get_product_info(struct es58x_device *es58x_dev)
+{
+	struct usb_device *udev = es58x_dev->udev;
+	const int es58x_prod_info_idx = 6;
+	/* Empirical tests show a prod_info length of maximum 83,
+	 * below should be more than enough.
+	 */
+	const size_t prod_info_len = 127;
+	char *prod_info;
+	int ret;
+
+	prod_info = kmalloc(prod_info_len, GFP_KERNEL);
+	if (!prod_info)
+		return -ENOMEM;
+
+	ret = usb_string(udev, es58x_prod_info_idx, prod_info, prod_info_len);
+	if (ret < 0) {
+		dev_err(es58x_dev->dev,
+			"%s: Could not read the product info: %pe\n",
+			__func__, ERR_PTR(ret));
+		return ret;
+	} else if (ret >= prod_info_len - 1) {
+		dev_warn(es58x_dev->dev,
+			 "%s: Buffer is too small, result might be truncated\n",
+			 __func__);
+	}
+	dev_info(es58x_dev->dev, "Product info: %s\n", prod_info);
+	kfree(prod_info);
+
+	return 0;
+}
+
+/**
+ * es58x_init_es58x_dev() - Initialize the ES58X device.
+ * @intf: USB interface
+ * @p_es58x_dev: pointer to the address of the ES58X device.
+ *
+ * Return: zero on success, errno when any error occurs.
+ */
+static int es58x_init_es58x_dev(struct usb_interface *intf,
+				struct es58x_device **p_es58x_dev)
+{
+	struct device *dev = &intf->dev;
+	struct es58x_device *es58x_dev;
+	const struct es58x_parameters *param;
+	const struct es58x_operators *ops;
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *ep_in, *ep_out;
+	const u16 usb_id_product = le16_to_cpu(udev->descriptor.idProduct);
+	u8 num_can_ch;
+	int ret;
+
+	dev_info(dev,
+		 "Starting %s %s (Serial Number %s) driver version %s\n",
+		 udev->manufacturer, udev->product, udev->serial, DRV_VERSION);
+
+	ret = usb_find_common_endpoints(intf->cur_altsetting, &ep_in, &ep_out,
+					NULL, NULL);
+	if (ret)
+		return ret;
+
+	switch (usb_id_product) {
+	case ES581_4_PRODUCT_ID:	/* 2 Classical CAN channels */
+		param = &es581_4_param;
+		ops = &es581_4_ops;
+		num_can_ch = ES581_4_NUM_CAN_CH;
+		break;
+
+	case ES582_1_PRODUCT_ID:	/* 2 CAN(-FD) channels */
+		param = &es58x_fd_param;
+		ops = &es58x_fd_ops;
+		num_can_ch = ES582_1_NUM_CAN_CH;
+		break;
+
+	case ES584_1_PRODUCT_ID:	/* 1 CAN(-FD) and 1 LIN channel */
+		param = &es58x_fd_param;
+		ops = &es58x_fd_ops;
+		num_can_ch = ES584_1_NUM_CAN_CH;
+		break;
+
+	default:
+		return -ENODEV;
+	}
+	if (num_can_ch > ARRAY_SIZE(es58x_dev->netdev) ||
+	    num_can_ch >= param->echo_skb_max)
+		return -ECHRNG;
+
+	es58x_dev = kzalloc(es58x_sizeof_es58x_device(param), GFP_KERNEL);
+	if (!es58x_dev)
+		return -ENOMEM;
+
+	es58x_dev->param = param;
+	es58x_dev->ops = ops;
+	es58x_dev->num_can_ch = num_can_ch;
+	es58x_dev->dev = dev;
+	es58x_dev->udev = udev;
+
+	init_usb_anchor(&es58x_dev->rx_urbs);
+	init_usb_anchor(&es58x_dev->tx_urbs_idle);
+	init_usb_anchor(&es58x_dev->tx_urbs_busy);
+	usb_set_intfdata(intf, es58x_dev);
+
+	es58x_dev->rx_pipe = usb_rcvbulkpipe(es58x_dev->udev,
+					     ep_in->bEndpointAddress);
+	es58x_dev->tx_pipe = usb_sndbulkpipe(es58x_dev->udev,
+					     ep_out->bEndpointAddress);
+	es58x_dev->rx_max_packet_size = le16_to_cpu(ep_in->wMaxPacketSize);
+
+	*p_es58x_dev = es58x_dev;
+
+	return 0;
+}
+
+/**
+ * es58x_probe() - Initialize the USB device.
+ * @intf: USB interface
+ * @id: USB device ID
+ *
+ * Return: zero on success, -ENODEV if the interface is not supported
+ * or errno when any other error occurs.
+ */
+static int es58x_probe(struct usb_interface *intf,
+		       const struct usb_device_id *id)
+{
+	struct es58x_device *es58x_dev;
+	int ch_idx, ret;
+
+	/* ES58X FD has some interface protocols unsupported by this driver. */
+	if (intf->cur_altsetting->desc.bInterfaceProtocol != 0) {
+		dev_dbg(&intf->dev, "Interface protocol %d is not supported\n",
+			intf->cur_altsetting->desc.bInterfaceProtocol);
+		return -ENODEV;
+	}
+
+	ret = es58x_init_es58x_dev(intf, &es58x_dev);
+	if (ret)
+		return ret;
+
+	ret = es58x_get_product_info(es58x_dev);
+	if (ret)
+		goto cleanup_es58x_dev;
+
+	for (ch_idx = 0; ch_idx < es58x_dev->num_can_ch; ch_idx++) {
+		ret = es58x_init_netdev(es58x_dev, ch_idx);
+		if (ret)
+			goto cleanup_candev;
+	}
+
+	ret = es58x_start(es58x_dev);
+	if (ret)
+		goto cleanup_candev;
+
+	es58x_set_realtime_diff_ns(es58x_dev);
+
+	return ret;
+
+ cleanup_candev:
+	for (ch_idx = 0; ch_idx < es58x_dev->num_can_ch; ch_idx++)
+		if (es58x_dev->netdev[ch_idx]) {
+			unregister_candev(es58x_dev->netdev[ch_idx]);
+			free_candev(es58x_dev->netdev[ch_idx]);
+		}
+ cleanup_es58x_dev:
+	kfree(es58x_dev);
+
+	return ret;
+}
+
+/**
+ * es58x_disconnect() - Disconnect the USB device.
+ * @intf: USB interface
+ *
+ * Called by the usb core when driver is unloaded or device is
+ * removed.
+ */
+static void es58x_disconnect(struct usb_interface *intf)
+{
+	struct es58x_device *es58x_dev = usb_get_intfdata(intf);
+	struct net_device *netdev;
+	struct urb *urb;
+	int i;
+
+	dev_info(&intf->dev, "Disconnecting %s %s\n",
+		 es58x_dev->udev->manufacturer, es58x_dev->udev->product);
+
+	for (i = 0; i < es58x_dev->num_can_ch; i++) {
+		netdev = es58x_dev->netdev[i];
+		if (!netdev)
+			continue;
+		netdev_dbg(netdev, "Unregistering %s\n", netdev->name);
+		unregister_candev(netdev);
+		netdev_dbg(netdev, "Freeing %s\n", netdev->name);
+		es58x_dev->netdev[i] = NULL;
+		free_candev(netdev);
+	}
+
+	dev_dbg(&intf->dev, "Killing TX busy anchored urbs\n");
+	if (!usb_wait_anchor_empty_timeout(&es58x_dev->tx_urbs_busy, 1000)) {
+		dev_err(&intf->dev, "%s: Timeout, some TX urbs still remain\n",
+			__func__);
+		usb_kill_anchored_urbs(&es58x_dev->tx_urbs_busy);
+	}
+
+	dev_dbg(&intf->dev, "Freeing TX idle anchored urbs\n");
+	while ((urb = usb_get_from_anchor(&es58x_dev->tx_urbs_idle)) != NULL) {
+		usb_free_coherent(urb->dev,
+				  es58x_dev->param->tx_urb_cmd_max_len,
+				  urb->transfer_buffer, urb->transfer_dma);
+		usb_free_urb(urb);
+		atomic_dec(&es58x_dev->tx_urbs_idle_cnt);
+	}
+	if (atomic_read(&es58x_dev->tx_urbs_idle_cnt) > 0)
+		dev_err(&intf->dev,
+			"All idle urbs were freed but tx_urb_idle_cnt is %u\n",
+			atomic_read(&es58x_dev->tx_urbs_idle_cnt));
+
+	dev_dbg(&intf->dev, "Unlinking RX anchored urbs\n");
+	usb_kill_anchored_urbs(&es58x_dev->rx_urbs);
+
+	dev_dbg(&intf->dev, "Freeing %s\n", es58x_dev->udev->product);
+	kfree(es58x_dev);
+	dev_dbg(&intf->dev, "Setting USB interface to NULL\n");
+	usb_set_intfdata(intf, NULL);
+}
+
+static struct usb_driver es58x_driver = {
+	.name = ES58X_MODULE_NAME,
+	.probe = es58x_probe,
+	.disconnect = es58x_disconnect,
+	.id_table = es58x_id_table,
+};
+
+module_usb_driver(es58x_driver);
diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.h b/drivers/net/can/usb/etas_es58x/es58x_core.h
new file mode 100644
index 000000000000..23e008c3d453
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es58x_core.h
@@ -0,0 +1,707 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_core.h: All common definitions and declarations.
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#ifndef __ES58X_COMMON_H__
+#define __ES58X_COMMON_H__
+
+#include <linux/types.h>
+#include <linux/usb.h>
+#include <linux/netdevice.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+
+#include "es581_4.h"
+#include "es58x_fd.h"
+
+/* Driver constants */
+#define ES58X_RX_URBS_MAX 5	/* Empirical value */
+#define ES58X_TX_URBS_MAX 8	/* Empirical value */
+
+#define ES58X_MAX(param)				\
+	(ES581_4_##param > ES58X_FD_##param ?		\
+		ES581_4_##param : ES58X_FD_##param)
+#define ES58X_TX_BULK_MAX ES58X_MAX(TX_BULK_MAX)
+#define ES58X_RX_BULK_MAX ES58X_MAX(RX_BULK_MAX)
+#define ES58X_RX_LOOPBACK_BULK_MAX ES58X_MAX(RX_LOOPBACK_BULK_MAX)
+#define ES58X_NUM_CAN_CH_MAX ES58X_MAX(NUM_CAN_CH)
+
+/* Use this when channel index is irrelevant (e.g. device
+ * timestamp).
+ */
+#define ES58X_CHANNEL_IDX_NA 0xFF
+#define ES58X_EMPTY_MSG NULL
+
+/* Threshold on consecutive CAN_STATE_ERROR_PASSIVE. If we receive
+ * ES58X_CONSECUTIVE_ERR_PASSIVE_MAX times the event
+ * ES58X_ERR_CRTL_PASSIVE in a row without any successful Rx or Tx,
+ * we force the device to switch to CAN_STATE_BUS_OFF state.
+ */
+#define ES58X_CONSECUTIVE_ERR_PASSIVE_MAX 254
+
+enum es58x_self_reception {
+	ES58X_SELF_RECEPTION_OFF = 0,
+	ES58X_SELF_RECEPTION_ON = 1
+};
+
+/**
+ * enum es58x_physical_layer - Type of the physical layer.
+ * @ES58X_PHYSICAL_LAYER_HIGH_SPEED: High-speed CAN (c.f. ISO
+ *	11898-2).
+ *
+ * Some products of the ETAS portfolio also support low-speed CAN
+ * (c.f. ISO 11898-3). However, all the devices in scope of this
+ * driver do not support the option, thus, the enum has only one
+ * member.
+ */
+enum es58x_physical_layer {
+	ES58X_PHYSICAL_LAYER_HIGH_SPEED = 1
+};
+
+enum es58x_samples_per_bit {
+	ES58X_SAMPLES_PER_BIT_ONE = 1,
+	ES58X_SAMPLES_PER_BIT_THREE = 2
+};
+
+/**
+ * enum es58x_sync_edge - Synchronization method.
+ * @ES58X_SYNC_EDGE_SINGLE: ISO CAN specification defines the use of a
+ *	single edge synchronization.  The synchronization should be
+ *	done on recessive to dominant level change.
+ *
+ * For information, ES582.1 and ES584.1 also support a double
+ * synchronization, requiring both recessive to dominant then dominant
+ * to recessive level change. However, this is not supported in
+ * SocketCAN framework, thus, the enum has only one member.
+ */
+enum es58x_sync_edge {
+	ES58X_SYNC_EDGE_SINGLE = 1
+};
+
+/**
+ * enum es58x_flag - CAN flags for RX/TX messages.
+ * @ES58X_FLAG_EFF: Extended Frame Format (EFF).
+ * @ES58X_FLAG_RTR: Remote Transmission Request (RTR).
+ * @ES58X_FLAG_FD_BRS: Bit rate switch (BRS): second bitrate for
+ *	payload data.
+ * @ES58X_FLAG_FD_ESI: Error State Indicator (ESI): tell if the
+ *	transmitting node is in error passive mode.
+ * @ES58X_FLAG_FD_DATA: CAN FD frame.
+ */
+enum es58x_flag {
+	ES58X_FLAG_EFF = BIT(0),
+	ES58X_FLAG_RTR = BIT(1),
+	ES58X_FLAG_FD_BRS = BIT(3),
+	ES58X_FLAG_FD_ESI = BIT(5),
+	ES58X_FLAG_FD_DATA = BIT(6)
+};
+
+/**
+ * enum es58x_err - CAN error detection.
+ * @ES58X_ERR_OK: No errors.
+ * @ES58X_ERR_PROT_STUFF: Bit stuffing error: more than 5 consecutive
+ *	equal bits.
+ * @ES58X_ERR_PROT_FORM: Frame format error.
+ * @ES58X_ERR_ACK: Received no ACK on transmission.
+ * @ES58X_ERR_PROT_BIT: Single bit error.
+ * @ES58X_ERR_PROT_CRC: Incorrect 15, 17 or 21 bits CRC.
+ * @ES58X_ERR_PROT_BIT1: Unable to send recessive bit: tried to send
+ *	recessive bit 1 but monitored dominant bit 0.
+ * @ES58X_ERR_PROT_BIT0: Unable to send dominant bit: tried to send
+ *	dominant bit 0 but monitored recessive bit 1.
+ * @ES58X_ERR_PROT_OVERLOAD: Bus overload.
+ * @ES58X_ERR_PROT_UNSPEC: Unspecified.
+ *
+ * Please refer to ISO 11898-1:2015, section 10.11 "Error detection"
+ * and section 10.13 "Overload signaling" for additional details.
+ */
+enum es58x_err {
+	ES58X_ERR_OK = 0,
+	ES58X_ERR_PROT_STUFF = BIT(0),
+	ES58X_ERR_PROT_FORM = BIT(1),
+	ES58X_ERR_ACK = BIT(2),
+	ES58X_ERR_PROT_BIT = BIT(3),
+	ES58X_ERR_PROT_CRC = BIT(4),
+	ES58X_ERR_PROT_BIT1 = BIT(5),
+	ES58X_ERR_PROT_BIT0 = BIT(6),
+	ES58X_ERR_PROT_OVERLOAD = BIT(7),
+	ES58X_ERR_PROT_UNSPEC = BIT(31)
+};
+
+/**
+ * enum es58x_event - CAN error codes returned by the device.
+ * @ES58X_EVENT_OK: No errors.
+ * @ES58X_EVENT_CRTL_ACTIVE: Active state: both TR and RX error count
+ *	is less than 128.
+ * @ES58X_EVENT_CRTL_PASSIVE: Passive state: either TX or RX error
+ *	count is greater than 127.
+ * @ES58X_EVENT_CRTL_WARNING: Warning state: either TX or RX error
+ *	count is greater than 96.
+ * @ES58X_EVENT_BUSOFF: Bus off.
+ * @ES58X_EVENT_SINGLE_WIRE: Lost connection on either CAN high or CAN
+ *	low.
+ *
+ * Please refer to ISO 11898-1:2015, section 12.1.4 "Rules of fault
+ * confinement" for additional details.
+ */
+enum es58x_event {
+	ES58X_EVENT_OK = 0,
+	ES58X_EVENT_CRTL_ACTIVE = BIT(0),
+	ES58X_EVENT_CRTL_PASSIVE = BIT(1),
+	ES58X_EVENT_CRTL_WARNING = BIT(2),
+	ES58X_EVENT_BUSOFF = BIT(3),
+	ES58X_EVENT_SINGLE_WIRE = BIT(4)
+};
+
+/**
+ * enum es58x_ret_u8 - Device return error codes, 8 bit format.
+ *
+ * Specific to ES581.4.
+ */
+enum es58x_ret_u8 {
+	ES58X_RET_U8_OK = 0x00,
+	ES58X_RET_U8_ERR_UNSPECIFIED_FAILURE = 0x80,
+	ES58X_RET_U8_ERR_NO_MEM = 0x81,
+	ES58X_RET_U8_ERR_BAD_CRC = 0x99
+};
+
+/**
+ * enum es58x_ret_u32 - Device return error codes, 32 bit format.
+ */
+enum es58x_ret_u32 {
+	ES58X_RET_U32_OK = 0x00000000UL,
+	ES58X_RET_U32_ERR_UNSPECIFIED_FAILURE = 0x80000000UL,
+	ES58X_RET_U32_ERR_NO_MEM = 0x80004001UL,
+	ES58X_RET_U32_WARN_PARAM_ADJUSTED = 0x40004000UL,
+	ES58X_RET_U32_WARN_TX_MAYBE_REORDER = 0x40004001UL,
+	ES58X_RET_U32_ERR_TIMEOUT = 0x80000008UL,
+	ES58X_RET_U32_ERR_FIFO_FULL = 0x80003002UL,
+	ES58X_RET_U32_ERR_BAD_CONFIG = 0x80004000UL,
+	ES58X_RET_U32_ERR_NO_RESOURCE = 0x80004002UL
+};
+
+/**
+ * enum es58x_ret_type - Type of the command returned by the ES58X
+ *	device.
+ */
+enum es58x_ret_type {
+	ES58X_RET_TYPE_SET_BITTIMING,
+	ES58X_RET_TYPE_ENABLE_CHANNEL,
+	ES58X_RET_TYPE_DISABLE_CHANNEL,
+	ES58X_RET_TYPE_TX_MSG,
+	ES58X_RET_TYPE_RESET_RX,
+	ES58X_RET_TYPE_RESET_TX,
+	ES58X_RET_TYPE_DEVICE_ERR,
+	ES58X_RET_TYPE_NUM_ENTRIES
+};
+
+union es58x_urb_cmd {
+	struct es581_4_urb_cmd es581_4_urb_cmd;
+	struct es58x_fd_urb_cmd es58x_fd_urb_cmd;
+	struct {		/* Common header parts of all variants */
+		__le16 sof;
+		u8 cmd_type;
+		u8 cmd_id;
+	} __packed;
+	u8 raw_cmd[0];
+};
+
+/**
+ * struct es58x_priv - All information specific to a CAN channel.
+ * @can: struct can_priv must be the first member (Socket CAN relies
+ *	on the fact that function netdev_priv() returns a pointer to
+ *	a struct can_priv).
+ * @es58x_dev: pointer to the corresponding ES58X device.
+ * @tx_urb: Used as a buffer to concatenate the TX messages and to do
+ *	a bulk send. Please refer to es58x_start_xmit() for more
+ *	details.
+ * @echo_skb_spinlock: Spinlock to protect the access to the echo skb
+ *	FIFO.
+ * @current_packet_idx: Keeps track of the packet indexes.
+ * @echo_skb_tail_idx: beginning of the echo skb FIFO, i.e. index of
+ *	the first element.
+ * @echo_skb_head_idx: end of the echo skb FIFO plus one, i.e. first
+ *	free index.
+ * @num_echo_skb: actual number of elements in the FIFO. Thus, the end
+ *	of the FIFO is echo_skb_head = (echo_skb_tail_idx +
+ *	num_echo_skb) % can.echo_skb_max.
+ * @tx_total_frame_len: sum, in bytes, of the length of each of the
+ *	CAN messages contained in @tx_urb. To be used as an input of
+ *	netdev_sent_queue() for BQL.
+ * @tx_can_msg_cnt: Number of messages in @tx_urb.
+ * @tx_can_msg_is_fd: false: all messages in @tx_urb are Classical
+ *	CAN, true: all messages in @tx_urb are CAN FD. Rationale:
+ *	ES58X FD devices do not allow to mix Classical CAN and FD CAN
+ *	frames in one single bulk transmission.
+ * @err_passive_before_rtx_success: The ES58X device might enter in a
+ *	state in which it keeps alternating between error passive
+ *	and active state. This counter keeps track of the number of
+ *	error passive and if it gets bigger than
+ *	ES58X_CONSECUTIVE_ERR_PASSIVE_MAX, es58x_rx_err_msg() will
+ *	force the status to bus-off.
+ * @channel_idx: Channel index, starts at zero.
+ */
+struct es58x_priv {
+	struct can_priv can;
+	struct es58x_device *es58x_dev;
+	struct urb *tx_urb;
+
+	spinlock_t echo_skb_spinlock;	/* Comments: c.f. supra */
+	u32 current_packet_idx;
+	u16 echo_skb_tail_idx;
+	u16 echo_skb_head_idx;
+	u16 num_echo_skb;
+
+	u16 tx_total_frame_len;
+	u8 tx_can_msg_cnt;
+	bool tx_can_msg_is_fd;
+
+	u8 err_passive_before_rtx_success;
+
+	u8 channel_idx;
+};
+
+/**
+ * struct es58x_parameters - Constant parameters of a given hardware
+ *	variant.
+ * @can_bittiming_const: Nominal bittimming parameters.
+ * @data_bittiming_const: Data bittiming parameters.
+ * @bitrate_max: Maximum bitrate supported by the device.
+ * @clock: CAN clock parameters.
+ * @ctrlmode_supported: List of supported modes. Please refer to
+ *	can/netlink.h file for additional details.
+ * @tx_start_of_frame: Magic number at the beginning of each TX URB
+ *	command.
+ * @rx_start_of_frame: Magic number at the beginning of each RX URB
+ *	command.
+ * @tx_urb_cmd_max_len: Maximum length of a TX URB command.
+ * @rx_urb_cmd_max_len: Maximum length of a RX URB command.
+ * @echo_skb_max: Maximum number of echo SKB. This value must not
+ *	exceed the maximum size of the device internal TX FIFO
+ *	length. This parameter is used to control the network queue
+ *	wake/stop logic.
+ * @dql_limit_min: Dynamic Queue Limits (DQL) absolute minimum limit
+ *	of bytes allowed to be queued on this network device transmit
+ *	queue. Used by the Byte Queue Limits (BQL) to determine how
+ *	frequently the xmit_more flag will be set to true in
+ *	es58x_start_xmit(). Set this value higher to optimize for
+ *	throughput but be aware that it might have a negative impact
+ *	on the latency! This value can also be set dynamically. Please
+ *	refer to Documentation/ABI/testing/sysfs-class-net-queues for
+ *	more details.
+ * @tx_bulk_max: Maximum number of Tx messages that can be sent in one
+ *	single URB packet.
+ * @urb_cmd_header_len: Length of the URB command header.
+ * @rx_urb_max: Number of RX URB to be allocated during device probe.
+ * @tx_urb_max: Number of TX URB to be allocated during device probe.
+ * @channel_idx_offset: Some of the ES58x starts channel numbering
+ *	from 0 (ES58X FD), others from 1 (ES581.4).
+ */
+struct es58x_parameters {
+	const struct can_bittiming_const *bittiming_const;
+	const struct can_bittiming_const *data_bittiming_const;
+	u32 bitrate_max;
+	struct can_clock clock;
+	u32 ctrlmode_supported;
+	u16 tx_start_of_frame;
+	u16 rx_start_of_frame;
+	u16 tx_urb_cmd_max_len;
+	u16 rx_urb_cmd_max_len;
+	u16 echo_skb_max;
+#ifdef CONFIG_BQL
+	u16 dql_limit_min;
+#endif
+	u8 tx_bulk_max;
+	u8 urb_cmd_header_len;
+	u8 rx_urb_max;
+	u8 tx_urb_max;
+	u8 channel_idx_offset;
+};
+
+/**
+ * struct es58x_operators - Function pointers used to encode/decode
+ *	the TX/RX messages.
+ * @get_msg_len: Get field msg_len of the urb_cmd. The offset of
+ *	msg_len inside urb_cmd depends of the device model.
+ * @handle_urb_cmd: Handle URB command received from the device and
+ *	manage the return code from device.
+ * @fill_urb_header: Fill the header of urb_cmd.
+ * @tx_can_msg: Encode a TX CAN message and add it to the bulk buffer
+ *	cmd_buf of es58x_dev.
+ * @set_bittiming: Encode the bittiming information and send it.
+ * @enable_channel: Start the CAN channel with index channel_idx.
+ * @disable_channel: Stop the CAN channel with index channel_idx.
+ * @reset_rx: Reset the RX queue of the ES58X device.
+ * @reset_tx: Reset the TX queue of the ES58X device.
+ * @get_timestamp: Request a timestamp from the ES58X device.
+ */
+struct es58x_operators {
+	u16 (*get_msg_len)(const union es58x_urb_cmd *urb_cmd);
+	int (*handle_urb_cmd)(struct es58x_device *es58x_dev,
+			      const union es58x_urb_cmd *urb_cmd);
+	void (*fill_urb_header)(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				u8 cmd_id, u8 channel_idx, u16 cmd_len);
+	int (*tx_can_msg)(struct es58x_priv *priv, int channel_idx,
+			  u32 packet_idx, const struct sk_buff *skb,
+			   union es58x_urb_cmd *urb_cmd, u32 *urb_cmd_len);
+	int (*set_bittiming)(struct es58x_device *es58x_dev, int channel_idx);
+	int (*enable_channel)(struct es58x_device *es58x_dev,
+			      int channel_idx);
+	int (*disable_channel)(struct es58x_device *es58x_dev,
+			       int channel_idx);
+	int (*reset_rx)(struct es58x_device *es58x_dev, int channel_idx);
+	int (*reset_tx)(struct es58x_device *es58x_dev, int channel_idx);
+	int (*get_timestamp)(struct es58x_device *es58x_dev);
+};
+
+/**
+ * struct es58x_device - All information specific to an ES58X device.
+ * @dev: Device information.
+ * @udev: USB device information.
+ * @netdev: Array of our CAN channels.
+ * @param: The constant parameters.
+ * @ops: Operators.
+ * @rx_pipe: USB reception pipe.
+ * @tx_pipe: USB transmission pipe.
+ * @rx_urbs: Anchor for received URBs.
+ * @tx_urbs_busy: Anchor for TX URBs which were send to the device.
+ * @tx_urbs_idle: Anchor for TX USB which are idle. This driver
+ *	allocates the memory for the URBs during the probe. When a TX
+ *	URB is needed, it can be taken from this anchor. The network
+ *	queue wake/stop logic should prevent this URB from getting
+ *	empty. Please refer to es58x_get_tx_urb() for more details.
+ * @tx_urbs_idle_cnt: number of urbs in @tx_urbs_idle.
+ * @ktime_req_ns: kernel timestamp when es58x_set_realtime_diff_ns()
+ *	was called.
+ * @realtime_diff_ns: difference in nanoseconds between the clocks of
+ *	the ES58X device and the kernel.
+ * @timestamps: a temporary buffer to store the time stamps before
+ *	feeding them to es58x_can_get_echo_skb(). Can only be used
+ *	in rx branches.
+ * @rx_max_packet_size: Maximum length of bulk-in URB.
+ * @num_can_ch: Number of CAN channel (i.e. number of elements of @netdev).
+ * @rx_cmd_buf_len: Length of @rx_cmd_buf.
+ * @rx_cmd_buf: The device might split the URB commands in an
+ *	arbitrary amount of pieces. This buffer is used to concatenate
+ *	all those pieces. Can only be used in rx branches. This field
+ *	has to be the last one of the structure because it is has a
+ *	flexible size (c.f. es58x_sizeof_es58x_device() function).
+ */
+struct es58x_device {
+	struct device *dev;
+	struct usb_device *udev;
+	struct net_device *netdev[ES58X_NUM_CAN_CH_MAX];
+
+	const struct es58x_parameters *param;
+	const struct es58x_operators *ops;
+
+	int rx_pipe;
+	int tx_pipe;
+
+	struct usb_anchor rx_urbs;
+	struct usb_anchor tx_urbs_busy;
+	struct usb_anchor tx_urbs_idle;
+	atomic_t tx_urbs_idle_cnt;
+
+	u64 ktime_req_ns;
+	s64 realtime_diff_ns;
+
+	u64 timestamps[ES58X_RX_LOOPBACK_BULK_MAX];
+
+	u16 rx_max_packet_size;
+	u8 num_can_ch;
+
+	u16 rx_cmd_buf_len;
+	union es58x_urb_cmd rx_cmd_buf;
+};
+
+/**
+ * es58x_sizeof_es58x_device() - Calculate the maximum length of
+ *	struct es58x_device.
+ * @es58x_dev_param: The constant parameters of the device.
+ *
+ * The length of struct es58x_device depends on the length of its last
+ * field: rx_cmd_buf. This macro allows to optimize size for memory
+ * allocation.
+ *
+ * Return: length of struct es58x_device.
+ */
+static inline size_t es58x_sizeof_es58x_device(const struct es58x_parameters
+					       *es58x_dev_param)
+{
+	return offsetof(struct es58x_device, rx_cmd_buf) +
+		es58x_dev_param->rx_urb_cmd_max_len;
+}
+
+/* Megabit per second (multiply x per one million) */
+#define ES58X_MBPS(x) (1000000UL * (x))
+
+/* Megahertz (multiply x per one million) */
+#define ES58X_MHZ(x) (1000000UL * (x))
+
+static inline int __es58x_check_msg_len(const struct device *dev,
+					const char *stringified_msg,
+					size_t actual_len, size_t expected_len)
+{
+	if (expected_len != actual_len) {
+		dev_err(dev,
+			"Length of %s is %zu but received command is %zu.\n",
+			stringified_msg, expected_len, actual_len);
+		return -EMSGSIZE;
+	}
+	return 0;
+}
+
+/**
+ * es58x_check_msg_len() - Check the size of a received message.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must not be a pointer.
+ * @actual_len: Length of the message as advertised in the command header.
+ *
+ * Must be a macro in order to retrieve the actual size using
+ * sizeof(). Can be use with any of the messages which have a fixed
+ * length. Check for an exact match of the size.
+ *
+ * Return: zero on success, -EMSGSIZE if @actual_len differs from the
+ * expected length.
+ */
+#define es58x_check_msg_len(dev, msg, actual_len)			\
+	__es58x_check_msg_len(dev, __stringify(msg),			\
+			      actual_len, sizeof(msg))
+
+static inline int __es58x_check_msg_max_len(const struct device *dev,
+					    const char *stringified_msg,
+					    size_t actual_len,
+					    size_t expected_len)
+{
+	if (actual_len > expected_len) {
+		dev_err(dev,
+			"Maximum length for %s is %zu but received command is %zu.\n",
+			stringified_msg, expected_len, actual_len);
+		return -EOVERFLOW;
+	}
+	return 0;
+}
+
+/**
+ * es58x_check_msg_max_len() - Check the maximum size of a received message.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must not be a pointer.
+ * @actual_len: Length of the message as advertised in the command header.
+ *
+ * Must be a macro in order to retrieve the actual size using
+ * sizeof(). To be used with the messages of variable sizes. Only
+ * check that the message is not bigger than the maximum expected
+ * size.
+ *
+ * Return: zero on success, -EOVERFLOW if @actual_len is greater than
+ * the expected length.
+ */
+#define es58x_check_msg_max_len(dev, msg, actual_len)			\
+	__es58x_check_msg_max_len(dev, __stringify(msg),		\
+				  actual_len, sizeof(msg))
+
+static inline int __es58x_msg_num_element(const struct device *dev,
+					  const char *stringified_msg,
+					  size_t actual_len, size_t msg_len,
+					  size_t elem_len)
+{
+	size_t actual_num_elem = actual_len / elem_len;
+	size_t expected_num_elem = msg_len / elem_len;
+
+	if (actual_num_elem == 0) {
+		dev_err(dev,
+			"Minimum length for %s is %zu but received command is %zu.\n",
+			stringified_msg, elem_len, actual_len);
+		return -EMSGSIZE;
+	} else if ((actual_len % elem_len) != 0) {
+		dev_err(dev,
+			"Received command length: %zu is not a multiple of %s[0]: %zu\n",
+			actual_len, stringified_msg, elem_len);
+		return -EMSGSIZE;
+	} else if (actual_num_elem > expected_num_elem) {
+		dev_err(dev,
+			"Array %s is supposed to have %zu elements each of size %zu...\n",
+			stringified_msg, expected_num_elem, elem_len);
+		dev_err(dev,
+			"... But received command has %zu elements (total length %zu).\n",
+			actual_num_elem, actual_len);
+		return -EOVERFLOW;
+	}
+	return actual_num_elem;
+}
+
+/**
+ * es58x_msg_num_element() - Check size and give the number of
+ *	elements in a message of array type.
+ * @dev: Device, used to print error messages.
+ * @msg: Received message, must be an array.
+ * @actual_len: Length of the message as advertised in the command
+ *	header.
+ *
+ * Must be a macro in order to retrieve the actual size using
+ * sizeof(). To be used on message of array type. Array's element has
+ * to be of fixed size (else use es58x_check_msg_max_len()). Check
+ * that the total length is an exact multiple of the length of a
+ * single element.
+ *
+ * Return: number of elements in the array on success, -EOVERFLOW if
+ * @actual_len is greater than the expected length, -EMSGSIZE if
+ * @actual_len is not a multiple of a single element.
+ */
+#define es58x_msg_num_element(dev, msg, actual_len)			\
+({									\
+	size_t __elem_len = sizeof((msg)[0]) + __must_be_array(msg);	\
+	__es58x_msg_num_element(dev, __stringify(msg), actual_len,	\
+				sizeof(msg), __elem_len);		\
+})
+
+/**
+ * es58x_priv() - Get the priv member and cast it to struct es58x_priv.
+ * @netdev: CAN network device.
+ *
+ * Return: ES58X device.
+ */
+static inline struct es58x_priv *es58x_priv(struct net_device *netdev)
+{
+	return (struct es58x_priv *)netdev_priv(netdev);
+}
+
+/**
+ * ES58X_SIZEOF_URB_CMD() - Calculate the maximum length of an urb
+ *	command for a given message field name.
+ * @es58x_urb_cmd_type: type (either "struct es581_4_urb_cmd" or
+ *	"struct es58x_fd_urb_cmd").
+ * @msg_field: name of the message field.
+ *
+ * Must be a macro in order to retrieve the actual size using
+ * offsetof() and sizeof_field().
+ *
+ * Return: length of the urb command.
+ */
+#define ES58X_SIZEOF_URB_CMD(es58x_urb_cmd_type, msg_field)		\
+	(offsetof(es58x_urb_cmd_type, raw_msg)				\
+		+ sizeof_field(es58x_urb_cmd_type, msg_field)		\
+		+ sizeof_field(es58x_urb_cmd_type,			\
+			       reserved_for_crc16_do_not_use))
+
+/**
+ * es58x_get_urb_cmd_len() - Calculate the actual length of an urb
+ *	command for a given message length.
+ * @es58x_dev: ES58X device.
+ * @msg_len: Length of the message.
+ *
+ * Add the header and CRC lengths to the message length.
+ *
+ * Return: length of the urb command.
+ */
+static inline size_t es58x_get_urb_cmd_len(struct es58x_device *es58x_dev,
+					   u16 msg_len)
+{
+	/* URB Length = URB header len + Message len + sizeof crc16 */
+	return es58x_dev->param->urb_cmd_header_len + msg_len + sizeof(u16);
+}
+
+/**
+ * es58x_get_netdev() - Get the network device.
+ * @es58x_dev: ES58X device.
+ * @channel_no: The channel number as advertised in the urb command.
+ * @netdev: CAN network device.
+ *
+ * ES581.4 starts the numbering on channels from 1, ES58X FD family
+ * starts it from 0. This method does the sanity check.
+ *
+ * Return: zero on success, -ECHRNG if the received channel number is
+ * out of range and -ENODEV if the network device is not yet
+ * configured.
+ */
+static inline int es58x_get_netdev(struct es58x_device *es58x_dev,
+				   int channel_no, struct net_device **netdev)
+{
+	int channel_idx = channel_no - es58x_dev->param->channel_idx_offset;
+
+	*netdev = NULL;
+	if (channel_idx < 0 || channel_idx >= es58x_dev->num_can_ch)
+		return -ECHRNG;
+
+	*netdev = es58x_dev->netdev[channel_idx];
+	if (!netdev || !netif_device_present(*netdev))
+		return -ENODEV;
+
+	return 0;
+}
+
+/**
+ * es58x_get_raw_can_id() - Get the CAN ID.
+ * @cf: CAN frame.
+ *
+ * Mask the CAN ID in order to only keep the significant bits.
+ *
+ * Return: the raw value of the CAN ID.
+ */
+static inline int es58x_get_raw_can_id(const struct can_frame *cf)
+{
+	if (cf->can_id & CAN_EFF_FLAG)
+		return cf->can_id & CAN_EFF_MASK;
+	else
+		return cf->can_id & CAN_SFF_MASK;
+}
+
+/**
+ * es58x_get_flags() - Get the CAN flags.
+ * @skb: socket buffer of a CAN message.
+ *
+ * Return: the CAN flag as an enum es58x_flag.
+ */
+static inline enum es58x_flag es58x_get_flags(const struct sk_buff *skb)
+{
+	struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+	enum es58x_flag es58x_flags = 0;
+
+	if (cf->can_id & CAN_EFF_FLAG)
+		es58x_flags |= ES58X_FLAG_EFF;
+
+	if (can_is_canfd_skb(skb)) {
+		es58x_flags |= ES58X_FLAG_FD_DATA;
+		if (cf->flags & CANFD_BRS)
+			es58x_flags |= ES58X_FLAG_FD_BRS;
+		if (cf->flags & CANFD_ESI)
+			es58x_flags |= ES58X_FLAG_FD_ESI;
+	} else if (cf->can_id & CAN_RTR_FLAG)
+		/* Remote frames are only defined in Classical CAN frames */
+		es58x_flags |= ES58X_FLAG_RTR;
+
+	return es58x_flags;
+}
+
+int es58x_can_get_echo_skb(struct net_device *netdev, u32 packet_idx,
+			   u64 *tstamps, unsigned int pkts);
+int es58x_tx_ack_msg(struct net_device *netdev, u16 tx_free_entries,
+		     enum es58x_ret_u32 rx_cmd_ret_u32);
+int es58x_rx_can_msg(struct net_device *netdev, u64 timestamp, const u8 *data,
+		     canid_t can_id, enum es58x_flag es58x_flags, u8 dlc);
+int es58x_rx_err_msg(struct net_device *netdev, enum es58x_err error,
+		     enum es58x_event event, u64 timestamp);
+int es58x_rx_timestamp(struct es58x_device *es58x_dev, u64 timestamp);
+int es58x_rx_dev_ret_u8(struct device *dev, enum es58x_ret_type cmd_ret_type,
+			enum es58x_ret_u8 rx_dev_ret_u8);
+int es58x_rx_cmd_ret_u32(struct net_device *netdev,
+			 enum es58x_ret_type cmd_ret_type,
+			 enum es58x_ret_u32 rx_cmd_ret_u32);
+int es58x_send_msg(struct es58x_device *es58x_dev, u8 cmd_type, u8 cmd_id,
+		   const void *msg, u16 cmd_len, int channel_idx);
+
+extern const struct es58x_parameters es581_4_param;
+extern const struct es58x_operators es581_4_ops;
+
+extern const struct es58x_parameters es58x_fd_param;
+extern const struct es58x_operators es58x_fd_ops;
+
+#endif /* __ES58X_COMMON_H__ */
diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.c b/drivers/net/can/usb/etas_es58x/es58x_fd.c
new file mode 100644
index 000000000000..6b9534f23c96
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es58x_fd.c
@@ -0,0 +1,662 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_fd.c: Adds support to ETAS ES582.1 and ES584.1 (naming
+ * convention: we use the term "ES58X FD" when referring to those two
+ * variants together).
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <asm/unaligned.h>
+
+#include "es58x_core.h"
+#include "es58x_fd.h"
+
+/**
+ * es58x_sizeof_rx_tx_msg() - Calculate the actual length of the
+ *	structure of a rx or tx message.
+ * @msg: message of variable length, must have a dlc and a len fields.
+ *
+ * Even if RTR frames have actually no payload, the ES58X devices
+ * still expect it. Must be a macro in order to retrieve the actual
+ * size using offsetof() and typeof().
+ *
+ * Return: length of the message.
+ */
+#define es58x_fd_sizeof_rx_tx_msg(msg)					\
+({									\
+	typeof(msg) __msg = (msg);					\
+	size_t __msg_len;						\
+									\
+	if (__msg.flags & ES58X_FLAG_FD_DATA)				\
+		__msg_len = canfd_sanitize_len(__msg.len);		\
+	else								\
+		__msg_len = can_cc_dlc2len(__msg.dlc);			\
+									\
+	(offsetof(typeof(__msg), data[__msg_len]));			\
+})
+
+static enum es58x_fd_cmd_type es58x_fd_cmd_type(struct net_device *netdev)
+{
+	u32 ctrlmode = es58x_priv(netdev)->can.ctrlmode;
+
+	return ctrlmode & (CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO) ?
+	    ES58X_FD_CMD_TYPE_CANFD : ES58X_FD_CMD_TYPE_CAN;
+}
+
+static u16 es58x_fd_get_msg_len(const union es58x_urb_cmd *urb_cmd)
+{
+	return get_unaligned_le16(&urb_cmd->es58x_fd_urb_cmd.msg_len);
+}
+
+static int es58x_fd_rx_loopback_msg(struct net_device *netdev,
+				    const struct es58x_fd_urb_cmd
+				    *es58x_fd_urb_cmd)
+{
+	struct es58x_priv *priv = es58x_priv(netdev);
+	const struct es58x_fd_rx_loopback_msg *rx_loopback_msg;
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	u64 *tstamps = es58x_dev->timestamps;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int i, num_element;
+	u32 first_packet_idx, packet_idx;
+	unsigned long flags;
+
+	const u32 mask = ~(u32)((typeof(rx_loopback_msg->packet_idx))(~0U));
+
+	num_element = es58x_msg_num_element(es58x_dev->dev,
+					    es58x_fd_urb_cmd->rx_loopback_msg,
+					    msg_len);
+	if (num_element < 0)
+		return num_element;
+	rx_loopback_msg = es58x_fd_urb_cmd->rx_loopback_msg;
+
+	spin_lock_irqsave(&priv->echo_skb_spinlock, flags);
+	first_packet_idx = priv->current_packet_idx - priv->num_echo_skb;
+	spin_unlock_irqrestore(&priv->echo_skb_spinlock, flags);
+
+	packet_idx = (first_packet_idx & mask) | rx_loopback_msg[0].packet_idx;
+	for (i = 0; i < num_element; i++) {
+		if ((u8)packet_idx != rx_loopback_msg[i].packet_idx) {
+			netdev_err(netdev, "Packet idx jumped from %u to %u\n",
+				   (u8)packet_idx - 1,
+				   rx_loopback_msg[i].packet_idx);
+			return -EBADMSG;
+		}
+
+		tstamps[i] = get_unaligned_le64(&rx_loopback_msg[i].timestamp);
+		packet_idx++;
+	}
+
+	return es58x_can_get_echo_skb(netdev, first_packet_idx,
+				      tstamps, num_element);
+}
+
+static int es58x_fd_rx_can_msg(struct net_device *netdev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	const u8 *rx_can_msg_buf = es58x_fd_urb_cmd->rx_can_msg_buf;
+	u16 rx_can_msg_buf_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int pkts, ret;
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es58x_fd_urb_cmd->rx_can_msg_buf,
+				      rx_can_msg_buf_len);
+	if (ret)
+		return ret;
+
+	for (pkts = 0; rx_can_msg_buf_len > 0; pkts++) {
+		const struct es58x_fd_rx_can_msg *rx_can_msg =
+		    (const struct es58x_fd_rx_can_msg *)rx_can_msg_buf;
+		bool is_can_fd = !!(rx_can_msg->flags & ES58X_FLAG_FD_DATA);
+		/* rx_can_msg_len is the length of the rx_can_msg
+		 * buffer. Not to be confused with rx_can_msg->len
+		 * which is the length of the CAN payload
+		 * rx_can_msg->data.
+		 */
+		u16 rx_can_msg_len = es58x_fd_sizeof_rx_tx_msg(*rx_can_msg);
+
+		if (rx_can_msg_len > rx_can_msg_buf_len) {
+			netdev_err(netdev,
+				   "%s: Expected a rx_can_msg of size %d but only %d bytes are left in rx_can_msg_buf\n",
+				   __func__,
+				   rx_can_msg_len, rx_can_msg_buf_len);
+			return -EMSGSIZE;
+		}
+		if (rx_can_msg->len > CANFD_MAX_DLEN) {
+			netdev_err(netdev,
+				   "%s: Data length is %d but maximum should be %d\n",
+				   __func__, rx_can_msg->len, CANFD_MAX_DLEN);
+			return -EMSGSIZE;
+		}
+
+		if (netif_running(netdev)) {
+			u64 tstamp = get_unaligned_le64(&rx_can_msg->timestamp);
+			canid_t can_id = get_unaligned_le32(&rx_can_msg->can_id);
+			u8 dlc;
+
+			if (is_can_fd)
+				dlc = can_fd_len2dlc(rx_can_msg->len);
+			else
+				dlc = rx_can_msg->dlc;
+
+			ret = es58x_rx_can_msg(netdev, tstamp, rx_can_msg->data,
+					       can_id, rx_can_msg->flags, dlc);
+			if (ret)
+				break;
+		}
+
+		rx_can_msg_buf_len -= rx_can_msg_len;
+		rx_can_msg_buf += rx_can_msg_len;
+	}
+
+	if (!netif_running(netdev)) {
+		if (net_ratelimit())
+			netdev_info(netdev,
+				    "%s: %s is down, dropping %d rx packets\n",
+				    __func__, netdev->name, pkts);
+		netdev->stats.rx_dropped += pkts;
+	}
+
+	return ret;
+}
+
+static int es58x_fd_rx_event_msg(struct net_device *netdev,
+				 const struct es58x_fd_urb_cmd
+				 *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	const struct es58x_fd_rx_event_msg *rx_event_msg;
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev, *rx_event_msg, msg_len);
+	if (ret)
+		return ret;
+
+	rx_event_msg = &es58x_fd_urb_cmd->rx_event_msg;
+
+	return es58x_rx_err_msg(netdev, rx_event_msg->error_code,
+				rx_event_msg->event_code,
+				get_unaligned_le64(&rx_event_msg->timestamp));
+}
+
+static int es58x_fd_rx_cmd_ret_u32(struct net_device *netdev,
+				   const struct es58x_fd_urb_cmd
+				   *es58x_fd_urb_cmd,
+				   enum es58x_ret_type cmd_ret_type)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	enum es58x_ret_u32 rx_cmd_ret_u32;
+	int ret;
+
+	ret = es58x_check_msg_len(es58x_dev->dev,
+				  es58x_fd_urb_cmd->rx_cmd_ret_le32, msg_len);
+	if (ret)
+		return ret;
+
+	rx_cmd_ret_u32 = get_unaligned_le32(&es58x_fd_urb_cmd->rx_cmd_ret_le32);
+
+	return es58x_rx_cmd_ret_u32(netdev, cmd_ret_type, rx_cmd_ret_u32);
+}
+
+static int es58x_fd_tx_ack_msg(struct net_device *netdev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct es58x_device *es58x_dev = es58x_priv(netdev)->es58x_dev;
+	const struct es58x_fd_tx_ack_msg *tx_ack_msg;
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	int ret;
+
+	tx_ack_msg = &es58x_fd_urb_cmd->tx_ack_msg;
+	ret = es58x_check_msg_len(es58x_dev->dev, *tx_ack_msg, msg_len);
+	if (ret)
+		return ret;
+
+	return
+	    es58x_tx_ack_msg(netdev,
+			     get_unaligned_le16(&tx_ack_msg->tx_free_entries),
+			     get_unaligned_le32(&tx_ack_msg->rx_cmd_ret_le32));
+}
+
+static int es58x_fd_can_cmd_id(struct es58x_device *es58x_dev,
+			       const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd)
+{
+	struct net_device *netdev;
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, es58x_fd_urb_cmd->channel_idx,
+			       &netdev);
+	if (ret)
+		return ret;
+
+	switch ((enum es58x_fd_can_cmd_id)es58x_fd_urb_cmd->cmd_id) {
+	case ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_ENABLE_CHANNEL);
+
+	case ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_DISABLE_CHANNEL);
+
+	case ES58X_FD_CAN_CMD_ID_TX_MSG:
+		return es58x_fd_tx_ack_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_MSG_SELFRX_ACK:
+		return es58x_fd_rx_loopback_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_RX_MSG:
+		return es58x_fd_rx_can_msg(netdev, es58x_fd_urb_cmd);
+
+	case ES58X_FD_CAN_CMD_ID_RESET_RX:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_RESET_RX);
+
+	case ES58X_FD_CAN_CMD_ID_RESET_TX:
+		return es58x_fd_rx_cmd_ret_u32(netdev, es58x_fd_urb_cmd,
+					       ES58X_RET_TYPE_RESET_TX);
+
+	case ES58X_FD_CAN_CMD_ID_ERROR_OR_EVENT_MSG:
+		return es58x_fd_rx_event_msg(netdev, es58x_fd_urb_cmd);
+
+	default:
+		return -EBADRQC;
+	}
+}
+
+static int es58x_fd_device_cmd_id(struct es58x_device *es58x_dev,
+				  const struct es58x_fd_urb_cmd
+				  *es58x_fd_urb_cmd)
+{
+	u16 msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	u64 timestamp;
+	int ret;
+
+	switch ((enum es58x_fd_dev_cmd_id)es58x_fd_urb_cmd->cmd_id) {
+	case ES58X_FD_DEV_CMD_ID_TIMESTAMP:
+		ret = es58x_check_msg_len(es58x_dev->dev,
+					  es58x_fd_urb_cmd->timestamp, msg_len);
+		if (ret)
+			return ret;
+		timestamp = get_unaligned_le64(&es58x_fd_urb_cmd->timestamp);
+		return es58x_rx_timestamp(es58x_dev, timestamp);
+
+	default:
+		return -EBADRQC;
+	}
+}
+
+static int es58x_fd_handle_urb_cmd(struct es58x_device *es58x_dev,
+				   const union es58x_urb_cmd *urb_cmd)
+{
+	const struct es58x_fd_urb_cmd *es58x_fd_urb_cmd;
+	const struct device *dev = es58x_dev->dev;
+	int ret;
+
+	es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+
+	switch ((enum es58x_fd_cmd_type)es58x_fd_urb_cmd->cmd_type) {
+	case ES58X_FD_CMD_TYPE_CAN:
+	case ES58X_FD_CMD_TYPE_CANFD:
+		ret = es58x_fd_can_cmd_id(es58x_dev, es58x_fd_urb_cmd);
+		break;
+
+	case ES58X_FD_CMD_TYPE_DEVICE:
+		ret = es58x_fd_device_cmd_id(es58x_dev, es58x_fd_urb_cmd);
+		break;
+
+	default:
+		ret = -EBADRQC;
+		break;
+	}
+
+	if (ret == -EBADRQC)
+		dev_err(dev,
+			"%s: Unknown command type (0x%02X) and command ID (0x%02X) combination\n",
+			__func__, es58x_fd_urb_cmd->cmd_type,
+			es58x_fd_urb_cmd->cmd_id);
+
+	return ret;
+}
+
+static void es58x_fd_fill_urb_header(union es58x_urb_cmd *urb_cmd, u8 cmd_type,
+				     u8 cmd_id, u8 channel_idx, u16 msg_len)
+{
+	struct es58x_fd_urb_cmd *es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+
+	es58x_fd_urb_cmd->SOF = cpu_to_le16(es58x_fd_param.tx_start_of_frame);
+	es58x_fd_urb_cmd->cmd_type = cmd_type;
+	es58x_fd_urb_cmd->cmd_id = cmd_id;
+	es58x_fd_urb_cmd->channel_idx = channel_idx;
+	es58x_fd_urb_cmd->msg_len = cpu_to_le16(msg_len);
+}
+
+static int es58x_fd_tx_can_msg(struct es58x_priv *priv, int channel_idx,
+			       u32 packet_idx, const struct sk_buff *skb,
+			       union es58x_urb_cmd *urb_cmd, u32 *urb_cmd_len)
+{
+	struct es58x_device *es58x_dev = priv->es58x_dev;
+	struct es58x_fd_urb_cmd *es58x_fd_urb_cmd = &urb_cmd->es58x_fd_urb_cmd;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct es58x_fd_tx_can_msg *tx_can_msg;
+	bool is_fd = can_is_canfd_skb(skb);
+	u16 msg_len;
+	int ret;
+
+	ret = es58x_check_msg_max_len(es58x_dev->dev,
+				      es58x_fd_urb_cmd->tx_can_msg_buf,
+				      es58x_fd_get_msg_len(urb_cmd) +
+				      sizeof(*tx_can_msg));
+	if (ret)
+		return ret;
+
+	msg_len = get_unaligned_le16(&es58x_fd_urb_cmd->msg_len);
+	tx_can_msg = (struct es58x_fd_tx_can_msg *)
+	    &es58x_fd_urb_cmd->tx_can_msg_buf[msg_len];
+
+	/* Fill message contents. */
+	if (*urb_cmd_len == es58x_dev->param->urb_cmd_header_len)
+		es58x_fd_fill_urb_header(urb_cmd,
+					 is_fd ? ES58X_FD_CMD_TYPE_CANFD
+					       : ES58X_FD_CMD_TYPE_CAN,
+					 ES58X_FD_CAN_CMD_ID_TX_MSG_NO_ACK,
+					 channel_idx, *urb_cmd_len);
+	tx_can_msg->packet_idx = packet_idx;
+	put_unaligned_le32(es58x_get_raw_can_id(cf), &tx_can_msg->can_id);
+	tx_can_msg->flags = (u8)es58x_get_flags(skb);
+	if (is_fd)
+		tx_can_msg->len = cf->len;
+	else
+		tx_can_msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
+	memcpy(tx_can_msg->data, cf->data, cf->len);
+
+	/* Calculate new sizes */
+	msg_len += es58x_fd_sizeof_rx_tx_msg(*tx_can_msg);
+	*urb_cmd_len = es58x_get_urb_cmd_len(es58x_dev, msg_len);
+	put_unaligned_le16(msg_len, &es58x_fd_urb_cmd->msg_len);
+
+	return 0;
+}
+
+/* ES58X uses the same command to set the bittiming parameters and
+ * enable the channel. The modification is done in
+ * es58x_fd_enable_channel().
+ */
+static int es58x_fd_set_bittiming(struct es58x_device *es58x_dev,
+				  int channel_idx)
+{
+	return 0;
+}
+
+static void es58x_fd_print_bittiming(struct net_device *netdev,
+				     struct es58x_fd_bittiming
+				     *es58x_fd_bittiming, char *type)
+{
+	netdev_vdbg(netdev, "bitrate %s    = %d\n", type,
+		    le32_to_cpu(es58x_fd_bittiming->bitrate));
+	netdev_vdbg(netdev, "tseg1 %s      = %d\n", type,
+		    le16_to_cpu(es58x_fd_bittiming->tseg1));
+	netdev_vdbg(netdev, "tseg2 %s      = %d\n", type,
+		    le16_to_cpu(es58x_fd_bittiming->tseg2));
+	netdev_vdbg(netdev, "brp %s        = %d\n", type,
+		    le16_to_cpu(es58x_fd_bittiming->brp));
+	netdev_vdbg(netdev, "sjw %s        = %d\n", type,
+		    le16_to_cpu(es58x_fd_bittiming->sjw));
+}
+
+static void es58x_fd_print_conf(struct net_device *netdev,
+				struct es58x_fd_tx_conf_msg *tx_conf_msg)
+{
+	es58x_fd_print_bittiming(netdev, &tx_conf_msg->nominal_bittiming,
+				 "nominal");
+	netdev_vdbg(netdev, "samples_per_bit    = %d\n",
+		    tx_conf_msg->samples_per_bit);
+	netdev_vdbg(netdev, "sync_edge          = %d\n",
+		    tx_conf_msg->sync_edge);
+	netdev_vdbg(netdev, "physical_layer     = %d\n",
+		    tx_conf_msg->physical_layer);
+	netdev_vdbg(netdev, "self_reception     = %d\n",
+		    tx_conf_msg->self_reception_mode);
+	netdev_vdbg(netdev, "ctrlmode           = %d\n", tx_conf_msg->ctrlmode);
+	netdev_vdbg(netdev, "canfd_enabled      = %d\n",
+		    tx_conf_msg->canfd_enabled);
+	if (tx_conf_msg->canfd_enabled) {
+		es58x_fd_print_bittiming(netdev,
+					 &tx_conf_msg->data_bittiming, "data");
+		netdev_vdbg(netdev,
+			    "Transmitter Delay Compensation        = %d\n",
+			    tx_conf_msg->tdc);
+		netdev_vdbg(netdev,
+			    "Transmitter Delay Compensation Offset = %d\n",
+			    le16_to_cpu(tx_conf_msg->tdco));
+		netdev_vdbg(netdev,
+			    "Transmitter Delay Compensation Filter = %d\n",
+			    le16_to_cpu(tx_conf_msg->tdcf));
+	}
+}
+
+static void es58x_fd_convert_bittiming(struct es58x_fd_bittiming *es58x_fd_bt,
+				       struct can_bittiming *bt)
+{
+	/* The actual value set in the hardware registers is one less
+	 * than the functional value.
+	 */
+	const int offset = 1;
+
+	es58x_fd_bt->bitrate = cpu_to_le32(bt->bitrate);
+	es58x_fd_bt->tseg1 =
+	    cpu_to_le16(bt->prop_seg + bt->phase_seg1 - offset);
+	es58x_fd_bt->tseg2 = cpu_to_le16(bt->phase_seg2 - offset);
+	es58x_fd_bt->brp = cpu_to_le16(bt->brp - offset);
+	es58x_fd_bt->sjw = cpu_to_le16(bt->sjw - offset);
+}
+
+static int es58x_fd_enable_channel(struct es58x_device *es58x_dev,
+				   int channel_idx)
+{
+	struct net_device *netdev = es58x_dev->netdev[channel_idx];
+	struct es58x_priv *priv = es58x_priv(netdev);
+	struct es58x_fd_tx_conf_msg tx_conf_msg = { 0 };
+	u32 ctrlmode;
+	bool is_can_fd = false;
+	size_t conf_len = 0;
+
+	es58x_fd_convert_bittiming(&tx_conf_msg.nominal_bittiming,
+				   &priv->can.bittiming);
+	ctrlmode = priv->can.ctrlmode;
+
+	tx_conf_msg.samples_per_bit =
+	    ctrlmode & CAN_CTRLMODE_3_SAMPLES ?
+	    ES58X_SAMPLES_PER_BIT_THREE : ES58X_SAMPLES_PER_BIT_ONE;
+	tx_conf_msg.sync_edge = ES58X_SYNC_EDGE_SINGLE;
+	tx_conf_msg.physical_layer = ES58X_PHYSICAL_LAYER_HIGH_SPEED;
+	tx_conf_msg.self_reception_mode = ES58X_SELF_RECEPTION_ON;
+
+	tx_conf_msg.ctrlmode |=
+	    ctrlmode & CAN_CTRLMODE_LISTENONLY ?
+	    ES58X_FD_CTRLMODE_PASSIVE : ES58X_FD_CTRLMODE_ACTIVE;
+
+	conf_len = ES58X_FD_CAN_CONF_LEN;
+	if (ctrlmode & CAN_CTRLMODE_FD) {
+		tx_conf_msg.ctrlmode |= ES58X_FD_CTRLMODE_FD_ISO;
+		is_can_fd = true;
+	} else if (ctrlmode & CAN_CTRLMODE_FD_NON_ISO) {
+		tx_conf_msg.ctrlmode |= ES58X_FD_CTRLMODE_FD_NON_ISO;
+		is_can_fd = true;
+	}
+	if (is_can_fd) {
+		struct can_bittiming *dbt = &priv->can.data_bittiming;
+		int tdco = 0;
+
+		conf_len = ES58X_FD_CANFD_CONF_LEN;
+
+		tx_conf_msg.canfd_enabled = !!is_can_fd;
+		es58x_fd_convert_bittiming(&tx_conf_msg.data_bittiming, dbt);
+
+		/* As specified in ISO 11898-1 section 11.3.3
+		 * "Transmitter delay compensation" (TDC) is only
+		 * applicable if data BRP is one or two.
+		 */
+		tx_conf_msg.tdc = (dbt->brp == 1) || (dbt->brp == 2);
+		if (tx_conf_msg.tdc) {
+			/* Set the Transmitter Delay Compensation
+			 * offset as the duration (in time quanta)
+			 * from the start of the bit to the sample
+			 * point.
+			 */
+			tdco = can_bit_time(dbt) * dbt->sample_point / 1000;
+		}
+		tx_conf_msg.tdco = cpu_to_le16(min_t(u16, 127, tdco));
+		tx_conf_msg.tdcf = cpu_to_le16(0);
+	}
+	es58x_fd_print_conf(netdev, &tx_conf_msg);
+
+	return es58x_send_msg(es58x_dev, es58x_fd_cmd_type(netdev),
+			      ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL,
+			      &tx_conf_msg, conf_len, channel_idx);
+}
+
+static int es58x_fd_disable_channel(struct es58x_device *es58x_dev,
+				    int channel_idx)
+{
+	/* The type (ES58X_FD_CMD_TYPE_CAN or ES58X_FD_CMD_TYPE_CANFD) does
+	 * not matter here.
+	 */
+	return es58x_send_msg(es58x_dev, ES58X_FD_CMD_TYPE_CAN,
+			      ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL,
+			      ES58X_EMPTY_MSG, 0, channel_idx);
+}
+
+static int es58x_fd_reset_rx(struct es58x_device *es58x_dev, int channel_idx)
+{
+	struct net_device *netdev;
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, channel_idx, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_send_msg(es58x_dev, es58x_fd_cmd_type(netdev),
+			      ES58X_FD_CAN_CMD_ID_RESET_RX, ES58X_EMPTY_MSG,
+			      0, channel_idx);
+}
+
+static int es58x_fd_reset_tx(struct es58x_device *es58x_dev, int channel_idx)
+{
+	struct net_device *netdev;
+	int ret;
+
+	ret = es58x_get_netdev(es58x_dev, channel_idx, &netdev);
+	if (ret)
+		return ret;
+
+	return es58x_send_msg(es58x_dev, es58x_fd_cmd_type(netdev),
+			      ES58X_FD_CAN_CMD_ID_RESET_TX, ES58X_EMPTY_MSG,
+			      0, channel_idx);
+}
+
+static int es58x_fd_get_timestamp(struct es58x_device *es58x_dev)
+{
+	return es58x_send_msg(es58x_dev, ES58X_FD_CMD_TYPE_DEVICE,
+			      ES58X_FD_DEV_CMD_ID_TIMESTAMP, ES58X_EMPTY_MSG,
+			      0, ES58X_CHANNEL_IDX_NA);
+}
+
+/* struct es58x_fd_nom_bittiming_const - Nominal bittiming constants.
+ *
+ * Nominal bittiming constants for ES582.1 and ES584.1 as specified in
+ * the microcontroller datasheet: "SAM E701/S70/V70/V71 Family"
+ * section 49.6.8 "MCAN Nominal Bit Timing and Prescaler Register"
+ * from Microchip.
+ *
+ * The values from the specification are the hardware register
+ * values. To convert them to the functional values, all ranges were
+ * incremented by 1 (e.g. range [0..n-1] changed to [1..n]).
+ */
+static const struct can_bittiming_const es58x_fd_nom_bittiming_const = {
+	.name = "ES582.1/ES584.1",
+	.tseg1_min = 2,
+	.tseg1_max = 256,
+	.tseg2_min = 2,
+	.tseg2_max = 128,
+	.sjw_max = 128,
+	.brp_min = 1,
+	.brp_max = 512,
+	.brp_inc = 1
+};
+
+/* struct es58x_fd_data_bittiming_const - Data bittiming constants.
+ *
+ * Data bittiming constants for ES582.1 and ES584.1 as specified in
+ * the microcontroller datasheet: "SAM E701/S70/V70/V71 Family"
+ * section 49.6.4 "MCAN Data Bit Timing and Prescaler Register" from
+ * Microchip.
+ */
+static const struct can_bittiming_const es58x_fd_data_bittiming_const = {
+	.name = "ES582.1/ES584.1",
+	.tseg1_min = 2,
+	.tseg1_max = 32,
+	.tseg2_min = 1,
+	.tseg2_max = 16,
+	.sjw_max = 8,
+	.brp_min = 1,
+	.brp_max = 32,
+	.brp_inc = 1
+};
+
+const struct es58x_parameters es58x_fd_param = {
+	.bittiming_const = &es58x_fd_nom_bittiming_const,
+	.data_bittiming_const = &es58x_fd_data_bittiming_const,
+	.bitrate_max = ES58X_MBPS(8),
+	.clock = {.freq = ES58X_MHZ(80)},
+	.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY |
+	    CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO |
+	    CAN_CTRLMODE_CC_LEN8_DLC,
+	.tx_start_of_frame = 0xCEFA,	/* FACE in little endian */
+	.rx_start_of_frame = 0xFECA,	/* CAFE in little endian */
+	.tx_urb_cmd_max_len = ES58X_FD_TX_URB_CMD_MAX_LEN,
+	.rx_urb_cmd_max_len = ES58X_FD_RX_URB_CMD_MAX_LEN,
+	/* Size of internal device TX queue is 500.
+	 *
+	 * However, when reaching value around 278, the device's busy
+	 * LED turns on and thus maximum value of 500 is never reached
+	 * in practice. Also, when this value is too high, some error
+	 * on the rx_loopback_msg were witnessed when the device is
+	 * recovering from bus off.
+	 *
+	 * For above reasons, a value that would prevent the device
+	 * from becoming busy was chosen. In practice, BQL would
+	 * prevent the value from even getting closer to below
+	 * maximum, so no impact on performance was measured.
+	 */
+	.echo_skb_max = U8_MAX,
+#ifdef CONFIG_BQL
+	/* Empirical value. */
+	.dql_limit_min = CAN_FRAME_LEN_MAX * 15,
+#endif
+	.tx_bulk_max = ES58X_FD_TX_BULK_MAX,
+	.urb_cmd_header_len = ES58X_FD_URB_CMD_HEADER_LEN,
+	.rx_urb_max = ES58X_RX_URBS_MAX,
+	.tx_urb_max = ES58X_TX_URBS_MAX,
+	.channel_idx_offset = 0
+};
+
+const struct es58x_operators es58x_fd_ops = {
+	.get_msg_len = es58x_fd_get_msg_len,
+	.handle_urb_cmd = es58x_fd_handle_urb_cmd,
+	.fill_urb_header = es58x_fd_fill_urb_header,
+	.tx_can_msg = es58x_fd_tx_can_msg,
+	.set_bittiming = es58x_fd_set_bittiming,
+	.enable_channel = es58x_fd_enable_channel,
+	.disable_channel = es58x_fd_disable_channel,
+	.reset_rx = es58x_fd_reset_rx,
+	.reset_tx = es58x_fd_reset_tx,
+	.get_timestamp = es58x_fd_get_timestamp
+};
diff --git a/drivers/net/can/usb/etas_es58x/es58x_fd.h b/drivers/net/can/usb/etas_es58x/es58x_fd.h
new file mode 100644
index 000000000000..79a13e08ea1a
--- /dev/null
+++ b/drivers/net/can/usb/etas_es58x/es58x_fd.h
@@ -0,0 +1,242 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Driver for ETAS GmbH ES58X USB CAN(-FD) Bus Interfaces.
+ *
+ * File es58x_fd.h: Definitions and declarations specific to ETAS
+ * ES582.1 and ES584.1 (naming convention: we use the term "ES58X FD"
+ * when referring to those two variants together).
+ *
+ * Copyright (C) 2019 Robert Bosch Engineering and Business
+ * Solutions. All rights reserved.
+ * Copyright (C) 2020 ETAS K.K.. All rights reserved.
+ */
+
+#ifndef __ES58X_FD_H__
+#define __ES58X_FD_H__
+
+#include <linux/types.h>
+
+#define ES582_1_NUM_CAN_CH 2
+#define ES584_1_NUM_CAN_CH 1
+#define ES58X_FD_NUM_CAN_CH 2
+
+#define ES58X_FD_TX_BULK_MAX 100
+#define ES58X_FD_RX_BULK_MAX 100
+#define ES58X_FD_RX_LOOPBACK_BULK_MAX 100
+
+enum es58x_fd_cmd_type {
+	ES58X_FD_CMD_TYPE_CAN = 0x03,
+	ES58X_FD_CMD_TYPE_CANFD = 0x04,
+	ES58X_FD_CMD_TYPE_DEVICE = 0xFF
+};
+
+/* Command IDs for ES58X_FD_CMD_TYPE_{CAN,CANFD}. */
+enum es58x_fd_can_cmd_id {
+	ES58X_FD_CAN_CMD_ID_ENABLE_CHANNEL = 0x01,
+	ES58X_FD_CAN_CMD_ID_DISABLE_CHANNEL = 0x02,
+	ES58X_FD_CAN_CMD_ID_TX_MSG = 0x05,
+	ES58X_FD_CAN_CMD_ID_MSG_SELFRX_ACK = 0x07,
+	ES58X_FD_CAN_CMD_ID_RX_MSG = 0x10,
+	ES58X_FD_CAN_CMD_ID_ERROR_OR_EVENT_MSG = 0x11,
+	ES58X_FD_CAN_CMD_ID_RESET_RX = 0x20,
+	ES58X_FD_CAN_CMD_ID_RESET_TX = 0x21,
+	ES58X_FD_CAN_CMD_ID_TX_MSG_NO_ACK = 0x55
+};
+
+/* Command IDs for ES58X_FD_CMD_TYPE_DEVICE. */
+enum es58x_fd_dev_cmd_id {
+	ES58X_FD_DEV_CMD_ID_GETTIMETICKS = 0x01,
+	ES58X_FD_DEV_CMD_ID_TIMESTAMP = 0x02
+};
+
+/**
+ * enum es58x_fd_ctrlmode - Controller mode.
+ * @ES58X_FD_CTRLMODE_ACTIVE: send and receive messages.
+ * @ES58X_FD_CTRLMODE_PASSIVE: only receive messages (monitor). Do not
+ *	send anything, not even the acknowledgment bit.
+ * @ES58X_FD_CTRLMODE_FD_ISO: CAN FD according to ISO11898-1.
+ * @ES58X_FD_CTRLMODE_FD_NON_ISO: follow Bosch CAN FD Specification
+ *	V1.0
+ * @ES58X_FD_CTRLMODE_DISABLE_PROTOCOL_EXCEPTION_HANDLING: How to
+ *	behave when CAN FD reserved bit is monitored as
+ *	dominant. (c.f. ISO 11898-1:2015, section 10.4.2.4 "Control
+ *	field", paragraph "r0 bit"). 0 (not disable = enable): send
+ *	error frame. 1 (disable): goes into bus integration mode
+ *	(c.f. below).
+ * @ES58X_FD_CTRLMODE_EDGE_FILTER_DURING_BUS_INTEGRATION: 0: Edge
+ *	filtering is disabled. 1: Edge filtering is enabled. Two
+ *	consecutive dominant bits required to detect an edge for hard
+ *	synchronization.
+ */
+enum es58x_fd_ctrlmode {
+	ES58X_FD_CTRLMODE_ACTIVE = 0,
+	ES58X_FD_CTRLMODE_PASSIVE = BIT(0),
+	ES58X_FD_CTRLMODE_FD_ISO = BIT(4),
+	ES58X_FD_CTRLMODE_FD_NON_ISO = BIT(5),
+	ES58X_FD_CTRLMODE_DISABLE_PROTOCOL_EXCEPTION_HANDLING = BIT(6),
+	ES58X_FD_CTRLMODE_EDGE_FILTER_DURING_BUS_INTEGRATION = BIT(7)
+};
+
+struct es58x_fd_bittiming {
+	__le32 bitrate;
+	__le16 tseg1;		/* range: [tseg1_min-1..tseg1_max-1] */
+	__le16 tseg2;		/* range: [tseg2_min-1..tseg2_max-1] */
+	__le16 brp;		/* range: [brp_min-1..brp_max-1] */
+	__le16 sjw;		/* range: [0..sjw_max-1] */
+} __packed;
+
+/**
+ * struct es58x_fd_tx_conf_msg - Channel configuration.
+ * @nominal_bittiming: Nominal bittiming.
+ * @samples_per_bit: type enum es58x_samples_per_bit.
+ * @sync_edge: type enum es58x_sync_edge.
+ * @physical_layer: type enum es58x_physical_layer.
+ * @self_reception_mode: type enum es58x_self_reception_mode.
+ * @ctrlmode: type enum es58x_fd_ctrlmode.
+ * @canfd_enabled: boolean (0: Classical CAN, 1: CAN and/or CANFD).
+ * @data_bittiming: Bittiming for flexible data-rate transmission.
+ * @tdc: Transmitter Delay Compensation switch (0: disabled, 1:
+ *	enabled). On very high bitrates, the delay between when the
+ *	bit is sent and received on the CANTX and CANRX pins of the
+ *	transceiver start to be significant enough for errors to occur
+ *	and thus need to be compensated.
+ * @tdco: Transmitter Delay Compensation Offset. Offset value, in time
+ *	quanta, defining the delay between the start of the bit
+ *	reception on the CANRX pin of the transceiver and the SSP
+ *	(Secondary Sample Point). Valid values: 0 to 127.
+ * @tdcf: Transmitter Delay Compensation Filter window. Defines the
+ *	minimum value for the SSP position, in time quanta. The
+ *	feature is enabled when TDCF is configured to a value greater
+ *	than TDCO. Valid values: 0 to 127.
+ *
+ * Please refer to the microcontroller datasheet: "SAM
+ * E701/S70/V70/V71 Family" section 49 "Controller Area Network
+ * (MCAN)" for additional information.
+ */
+struct es58x_fd_tx_conf_msg {
+	struct es58x_fd_bittiming nominal_bittiming;
+	u8 samples_per_bit;
+	u8 sync_edge;
+	u8 physical_layer;
+	u8 self_reception_mode;
+	u8 ctrlmode;
+	u8 canfd_enabled;
+	struct es58x_fd_bittiming data_bittiming;
+	u8 tdc;
+	__le16 tdco;
+	__le16 tdcf;
+} __packed;
+
+#define ES58X_FD_CAN_CONF_LEN					\
+	(offsetof(struct es58x_fd_tx_conf_msg, canfd_enabled))
+#define ES58X_FD_CANFD_CONF_LEN (sizeof(struct es58x_fd_tx_conf_msg))
+
+struct es58x_fd_tx_can_msg {
+	u8 packet_idx;
+	__le32 can_id;
+	u8 flags;
+	union {
+		u8 dlc;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CAN */
+		u8 len;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CANFD */
+	} __packed;
+	u8 data[CANFD_MAX_DLEN];
+} __packed;
+
+#define ES58X_FD_CAN_TX_LEN						\
+	(offsetof(struct es58x_fd_tx_can_msg, data[CAN_MAX_DLEN]))
+#define ES58X_FD_CANFD_TX_LEN (sizeof(struct es58x_fd_tx_can_msg))
+
+struct es58x_fd_rx_can_msg {
+	__le64 timestamp;
+	__le32 can_id;
+	u8 flags;
+	union {
+		u8 dlc;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CAN */
+		u8 len;		/* Only if cmd_id is ES58X_FD_CMD_TYPE_CANFD */
+	} __packed;
+	u8 data[CANFD_MAX_DLEN];
+} __packed;
+
+#define ES58X_FD_CAN_RX_LEN						\
+	(offsetof(struct es58x_fd_rx_can_msg, data[CAN_MAX_DLEN]))
+#define ES58X_FD_CANFD_RX_LEN (sizeof(struct es58x_fd_rx_can_msg))
+
+struct es58x_fd_rx_loopback_msg {
+	__le64 timestamp;
+	u8 packet_idx;
+} __packed;
+
+struct es58x_fd_rx_event_msg {
+	__le64 timestamp;
+	__le32 can_id;
+	u8 flags;		/* type enum es58x_flag */
+	u8 error_type;		/* 0: event, 1: error */
+	u8 error_code;
+	u8 event_code;
+} __packed;
+
+struct es58x_fd_tx_ack_msg {
+	__le32 rx_cmd_ret_le32;	/* type enum es58x_cmd_ret_code_u32 */
+	__le16 tx_free_entries;	/* Number of remaining free entries in the device TX queue */
+} __packed;
+
+/**
+ * struct es58x_fd_urb_cmd - Commands received from or sent to the
+ *	ES58X FD device.
+ * @SOF: Start of Frame.
+ * @cmd_type: Command Type (type: enum es58x_fd_cmd_type). The CRC
+ *	calculation starts at this position.
+ * @cmd_id: Command ID (type: enum es58x_fd_cmd_id).
+ * @channel_idx: Channel index starting at 0.
+ * @msg_len: Length of the message, excluding CRC (i.e. length of the
+ *	union).
+ * @tx_conf_msg: Channel configuration.
+ * @tx_can_msg_buf: Concatenation of Tx messages. Type is "u8[]"
+ *	instead of "struct es58x_fd_tx_msg[]" because the structure
+ *	has a flexible size.
+ * @rx_can_msg_buf: Concatenation Rx messages. Type is "u8[]" instead
+ *	of "struct es58x_fd_rx_msg[]" because the structure has a
+ *	flexible size.
+ * @rx_loopback_msg: Array of loopback messages.
+ * @rx_event_msg: Error or event message.
+ * @tx_ack_msg: Tx acknowledgment message.
+ * @timestamp: Timestamp reply.
+ * @rx_cmd_ret_le32: Rx 32 bits return code (type: enum
+ *	es58x_cmd_ret_code_u32).
+ * @raw_msg: Message raw payload.
+ * @reserved_for_crc16_do_not_use: The structure ends with a
+ *	CRC16. Because the structures in above union are of variable
+ *	lengths, we can not predict the offset of the CRC in
+ *	advance. Use functions es58x_get_crc() and es58x_set_crc() to
+ *	manipulate it.
+ */
+struct es58x_fd_urb_cmd {
+	__le16 SOF;
+	u8 cmd_type;
+	u8 cmd_id;
+	u8 channel_idx;
+	__le16 msg_len;
+
+	union {
+		struct es58x_fd_tx_conf_msg tx_conf_msg;
+		u8 tx_can_msg_buf[ES58X_FD_TX_BULK_MAX * ES58X_FD_CANFD_TX_LEN];
+		u8 rx_can_msg_buf[ES58X_FD_RX_BULK_MAX * ES58X_FD_CANFD_RX_LEN];
+		struct es58x_fd_rx_loopback_msg
+		 rx_loopback_msg[ES58X_FD_RX_LOOPBACK_BULK_MAX];
+		struct es58x_fd_rx_event_msg rx_event_msg;
+		struct es58x_fd_tx_ack_msg tx_ack_msg;
+		__le64 timestamp;
+		__le32 rx_cmd_ret_le32;
+		u8 raw_msg[0];
+	} __packed;
+
+	__le16 reserved_for_crc16_do_not_use;
+} __packed;
+
+#define ES58X_FD_URB_CMD_HEADER_LEN (offsetof(struct es58x_fd_urb_cmd, raw_msg))
+#define ES58X_FD_TX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es58x_fd_urb_cmd, tx_can_msg_buf)
+#define ES58X_FD_RX_URB_CMD_MAX_LEN					\
+	ES58X_SIZEOF_URB_CMD(struct es58x_fd_urb_cmd, rx_can_msg_buf)
+
+#endif /* __ES58X_FD_H__ */