diff mbox series

[net-next,12/12] net: dsa: tag_ocelot_8021q: add support for PTP timestamping

Message ID 20210213001412.4154051-13-olteanv@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series PTP for DSA tag_ocelot_8021q | expand

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netdev/stable success Stable not CCed

Commit Message

Vladimir Oltean Feb. 13, 2021, 12:14 a.m. UTC 
From: Vladimir Oltean <vladimir.oltean@nxp.com>

On TX, use the result of the ptp_classify_raw() BPF classifier from
dsa_skb_tx_timestamp() to divert some frames over to the MMIO-based
injection registers.

On RX, set up a VCAP IS2 rule that redirects the frames with an
EtherType for 1588 to the CPU port module (for MMIO based extraction)
and, if the "no XTR IRQ" workaround is in place, copies them to the
dsa_8021q CPU port as well (for notification).

There is a conflict between the VCAP IS2 trapping rule and the semantics
of the BPF classifier. Namely, ptp_classify_raw() deems general messages
as non-timestampable, but still, those are trapped to the CPU port
module since they have an EtherType of ETH_P_1588. So, if the "no XTR
IRQ" workaround is in place, we need to run another BPF classifier on
the frames extracted over MMIO, to avoid duplicates being sent to the
stack (once over Ethernet, once over MMIO). It doesn't look like it's
possible to install VCAP IS2 rules based on keys extracted from the 1588
frame headers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/dsa/ocelot/felix.c             | 69 ++++++++++++++++++++++
 drivers/net/ethernet/mscc/ocelot.c         |  7 +++
 drivers/net/ethernet/mscc/ocelot_vsc7514.c |  3 +-
 include/soc/mscc/ocelot.h                  |  1 +
 net/dsa/tag_ocelot_8021q.c                 | 30 ++++++++++
 5 files changed, 108 insertions(+), 2 deletions(-)

Comments

kernel test robot Feb. 13, 2021, 7:42 a.m. UTC | #1 
Hi Vladimir,

I love your patch! Yet something to improve:

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Vladimir-Oltean/PTP-for-DSA-tag_ocelot_8021q/20210213-081857
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 3c5a2fd042d0bfac71a2dfb99515723d318df47b
config: i386-randconfig-a011-20210209 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/252148a7a654decce0740262c5425991fd53156e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Vladimir-Oltean/PTP-for-DSA-tag_ocelot_8021q/20210213-081857
        git checkout 252148a7a654decce0740262c5425991fd53156e
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

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 >>):

   ld: net/dsa/tag_ocelot_8021q.o: in function `ocelot_xmit_ptp':
>> net/dsa/tag_ocelot_8021q.c:34: undefined reference to `ocelot_port_inject_frame'


vim +34 net/dsa/tag_ocelot_8021q.c

    15	
    16	static struct sk_buff *ocelot_xmit_ptp(struct dsa_port *dp,
    17					       struct sk_buff *skb,
    18					       struct sk_buff *clone)
    19	{
    20		struct ocelot *ocelot = dp->ds->priv;
    21		struct ocelot_port *ocelot_port;
    22		int port = dp->index;
    23		u32 rew_op;
    24	
    25		ocelot_port = ocelot->ports[port];
    26		rew_op = ocelot_port->ptp_cmd;
    27	
    28		/* Retrieve timestamp ID populated inside skb->cb[0] of the
    29		 * clone by ocelot_port_add_txtstamp_skb
    30		 */
    31		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
    32			rew_op |= clone->cb[0] << 3;
    33	
  > 34		ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
    35	
    36		return NULL;
    37	}
    38	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Vladimir Oltean Feb. 13, 2021, 11:14 a.m. UTC | #2 
On Sat, Feb 13, 2021 at 03:42:46PM +0800, kernel test robot wrote:
>    ld: net/dsa/tag_ocelot_8021q.o: in function `ocelot_xmit_ptp':
> >> net/dsa/tag_ocelot_8021q.c:34: undefined reference to `ocelot_port_inject_frame'

Good catch, the problem is that the DSA taggers can be built without
support for the switch driver. I've created some shim definitions in
include/soc/mscc/ocelot.h:

/* Packet I/O */
#if IS_ENABLED(CONFIG_MSCC_OCELOT_SWITCH_LIB)

bool ocelot_can_inject(struct ocelot *ocelot, int grp);
void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
			      u32 rew_op, struct sk_buff *skb);
int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **skb);
void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp);

#else

static inline bool ocelot_can_inject(struct ocelot *ocelot, int grp)
{
	return true;
}

static inline void ocelot_port_inject_frame(struct ocelot *ocelot, int port,
					    int grp, u32 rew_op,
					    struct sk_buff *skb)
{
}

static inline int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp,
					struct sk_buff **skb)
{
	return -EIO;
}

static inline void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp)
{
}

#endif
diff mbox series

Patch

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index d3b18aa6a582..b2e6a5b14f02 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -16,6 +16,7 @@ 
 #include <linux/dsa/8021q.h>
 #include <linux/dsa/ocelot.h>
 #include <linux/platform_device.h>
+#include <linux/ptp_classify.h>
 #include <linux/module.h>
 #include <linux/of_net.h>
 #include <linux/pci.h>
@@ -345,6 +346,15 @@  static int felix_setup_mmio_filtering(struct felix *felix)
 		return ret;
 	}
 
+	/* The ownership of the CPU port module's queues might have just been
+	 * transferred to the tag_8021q tagger from the NPI-based tagger.
+	 * So there might still be all sorts of crap in the queues. On the
+	 * other hand, the MMIO-based matching of PTP frames is very brittle,
+	 * so we need to be careful that there are no extra frames to be
+	 * dequeued over MMIO, since we would never know to discard them.
+	 */
+	ocelot_drain_cpu_queue(ocelot, 0);
+
 	return 0;
 }
 
@@ -1283,6 +1293,55 @@  static int felix_hwtstamp_set(struct dsa_switch *ds, int port,
 	return ocelot_hwstamp_set(ocelot, port, ifr);
 }
 
+static bool felix_check_xtr_pkt(struct ocelot *ocelot, unsigned int ptp_type)
+{
+	struct felix *felix = ocelot_to_felix(ocelot);
+	int err, grp = 0;
+
+	if (felix->tag_proto != DSA_TAG_PROTO_OCELOT_8021Q)
+		return false;
+
+	if (!felix->info->quirk_no_xtr_irq)
+		return false;
+
+	if (ptp_type == PTP_CLASS_NONE)
+		return false;
+
+	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp)) {
+		struct sk_buff *skb;
+		unsigned int type;
+
+		err = ocelot_xtr_poll_frame(ocelot, grp, &skb);
+		if (err)
+			goto out;
+
+		/* We trap to the CPU port module all PTP frames, but
+		 * felix_rxtstamp() only gets called for event frames.
+		 * So we need to avoid sending duplicate general
+		 * message frames by running a second BPF classifier
+		 * here and dropping those.
+		 */
+		__skb_push(skb, ETH_HLEN);
+
+		type = ptp_classify_raw(skb);
+
+		__skb_pull(skb, ETH_HLEN);
+
+		if (type == PTP_CLASS_NONE) {
+			kfree_skb(skb);
+			continue;
+		}
+
+		netif_rx(skb);
+	}
+
+out:
+	if (err < 0)
+		ocelot_drain_cpu_queue(ocelot, 0);
+
+	return true;
+}
+
 static bool felix_rxtstamp(struct dsa_switch *ds, int port,
 			   struct sk_buff *skb, unsigned int type)
 {
@@ -1293,6 +1352,16 @@  static bool felix_rxtstamp(struct dsa_switch *ds, int port,
 	struct timespec64 ts;
 	u64 tstamp, val;
 
+	/* If the "no XTR IRQ" workaround is in use, tell DSA to defer this skb
+	 * for RX timestamping. Then free it, and poll for its copy through
+	 * MMIO in the CPU port module, and inject that into the stack from
+	 * ocelot_xtr_poll().
+	 */
+	if (felix_check_xtr_pkt(ocelot, type)) {
+		kfree_skb(skb);
+		return true;
+	}
+
 	ocelot_ptp_gettime64(&ocelot->ptp_info, &ts);
 	tstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
 
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 981811ffcdae..8d97c731e953 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -837,6 +837,13 @@  void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 }
 EXPORT_SYMBOL(ocelot_port_inject_frame);
 
+void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp)
+{
+	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
+		ocelot_read_rix(ocelot, QS_XTR_RD, grp);
+}
+EXPORT_SYMBOL(ocelot_drain_cpu_queue);
+
 int ocelot_fdb_add(struct ocelot *ocelot, int port,
 		   const unsigned char *addr, u16 vid)
 {
diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index 47ee06832a51..4bd7e9d9ec61 100644
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -552,8 +552,7 @@  static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 
 out:
 	if (err < 0)
-		while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
-			ocelot_read_rix(ocelot, QS_XTR_RD, grp);
+		ocelot_drain_cpu_queue(ocelot, 0);
 
 	return IRQ_HANDLED;
 }
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index a3ff09f9d3b4..6de00762e8c2 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -844,5 +844,6 @@  bool ocelot_can_inject(struct ocelot *ocelot, int grp);
 void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 			      u32 rew_op, struct sk_buff *skb);
 int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **skb);
+void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp);
 
 #endif
diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
index 190255d06bef..da5f682cd647 100644
--- a/net/dsa/tag_ocelot_8021q.c
+++ b/net/dsa/tag_ocelot_8021q.c
@@ -9,8 +9,33 @@ 
  *   that on egress
  */
 #include <linux/dsa/8021q.h>
+#include <soc/mscc/ocelot.h>
+#include <soc/mscc/ocelot_ptp.h>
 #include "dsa_priv.h"
 
+static struct sk_buff *ocelot_xmit_ptp(struct dsa_port *dp,
+				       struct sk_buff *skb,
+				       struct sk_buff *clone)
+{
+	struct ocelot *ocelot = dp->ds->priv;
+	struct ocelot_port *ocelot_port;
+	int port = dp->index;
+	u32 rew_op;
+
+	ocelot_port = ocelot->ports[port];
+	rew_op = ocelot_port->ptp_cmd;
+
+	/* Retrieve timestamp ID populated inside skb->cb[0] of the
+	 * clone by ocelot_port_add_txtstamp_skb
+	 */
+	if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
+		rew_op |= clone->cb[0] << 3;
+
+	ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
+
+	return NULL;
+}
+
 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 				   struct net_device *netdev)
 {
@@ -18,6 +43,11 @@  static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
 	u16 queue_mapping = skb_get_queue_mapping(skb);
 	u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
+	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
+
+	/* TX timestamping was requested, so inject through MMIO */
+	if (clone)
+		return ocelot_xmit_ptp(dp, skb, clone);
 
 	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
 			      ((pcp << VLAN_PRIO_SHIFT) | tx_vid));