diff mbox series

[1/8] usb: typec: Add driver for Thunderbolt 3 Alternate Mode

Message ID 20240925092505.1.I3080b036e8de0b9957c57c1c3059db7149c5e549@changeid (mailing list archive)
State Superseded
Headers show
Series Thunderbolt and DP altmode support for cros-ec-typec | expand

Commit Message

Abhishek Pandit-Subedi Sept. 25, 2024, 4:25 p.m. UTC
From: Heikki Krogerus <heikki.krogerus@linux.intel.com>

Thunderbolt 3 Alternate Mode entry flow is described in
USB Type-C Specification Release 2.0.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
---

Changes:
* Delay cable + plug checks so that the module doesn't fail to probe
  if cable + plug information isn't available by the time the partner
  altmode is registered.
* Remove unncessary brace after if (IS_ERR(plug))

The rest of this patch should be the same as Heikki's original RFC.


 drivers/usb/typec/altmodes/Kconfig       |   9 +
 drivers/usb/typec/altmodes/Makefile      |   2 +
 drivers/usb/typec/altmodes/thunderbolt.c | 321 +++++++++++++++++++++++
 3 files changed, 332 insertions(+)
 create mode 100644 drivers/usb/typec/altmodes/thunderbolt.c

Comments

Heikki Krogerus Sept. 26, 2024, 2:06 p.m. UTC | #1
Hi Abhishek,

On Wed, Sep 25, 2024 at 09:25:02AM -0700, Abhishek Pandit-Subedi wrote:
> From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> 
> Thunderbolt 3 Alternate Mode entry flow is described in
> USB Type-C Specification Release 2.0.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
> ---
> 
> Changes:
> * Delay cable + plug checks so that the module doesn't fail to probe
>   if cable + plug information isn't available by the time the partner
>   altmode is registered.
> * Remove unncessary brace after if (IS_ERR(plug))
> 
> The rest of this patch should be the same as Heikki's original RFC.
> 
> 
>  drivers/usb/typec/altmodes/Kconfig       |   9 +
>  drivers/usb/typec/altmodes/Makefile      |   2 +
>  drivers/usb/typec/altmodes/thunderbolt.c | 321 +++++++++++++++++++++++
>  3 files changed, 332 insertions(+)
>  create mode 100644 drivers/usb/typec/altmodes/thunderbolt.c
> 
> diff --git a/drivers/usb/typec/altmodes/Kconfig b/drivers/usb/typec/altmodes/Kconfig
> index 1a6b5e872b0d..7867fa7c405d 100644
> --- a/drivers/usb/typec/altmodes/Kconfig
> +++ b/drivers/usb/typec/altmodes/Kconfig
> @@ -23,4 +23,13 @@ config TYPEC_NVIDIA_ALTMODE
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called typec_nvidia.
>  
> +config TYPEC_TBT_ALTMODE
> +	tristate "Thunderbolt3 Alternate Mode driver"
> +	help
> +	  Select this option if you have Thunderbolt3 hardware on your
> +	  system.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called typec_thunderbolt.
> +
>  endmenu
> diff --git a/drivers/usb/typec/altmodes/Makefile b/drivers/usb/typec/altmodes/Makefile
> index 45717548b396..508a68351bd2 100644
> --- a/drivers/usb/typec/altmodes/Makefile
> +++ b/drivers/usb/typec/altmodes/Makefile
> @@ -4,3 +4,5 @@ obj-$(CONFIG_TYPEC_DP_ALTMODE)		+= typec_displayport.o
>  typec_displayport-y			:= displayport.o
>  obj-$(CONFIG_TYPEC_NVIDIA_ALTMODE)	+= typec_nvidia.o
>  typec_nvidia-y				:= nvidia.o
> +obj-$(CONFIG_TYPEC_TBT_ALTMODE)		+= typec_thunderbolt.o
> +typec_thunderbolt-y			:= thunderbolt.o
> diff --git a/drivers/usb/typec/altmodes/thunderbolt.c b/drivers/usb/typec/altmodes/thunderbolt.c
> new file mode 100644
> index 000000000000..515e775ee41a
> --- /dev/null
> +++ b/drivers/usb/typec/altmodes/thunderbolt.c
> @@ -0,0 +1,321 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * USB Typec-C Thuderbolt3 Alternate Mode driver
> + *
> + * Copyright (C) 2019 Intel Corporation
> + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/module.h>
> +#include <linux/usb/pd_vdo.h>
> +#include <linux/usb/typec_altmode.h>
> +
> +#define USB_TYPEC_VENDOR_INTEL		0x8087
> +
> +/* TBT3 Device Discover Mode VDO bits */
> +#define TBT_MODE			BIT(0)
> +#define TBT_ADAPTER(_vdo_)		(((_vdo_) & BIT(16)) >> 16)
> +#define   TBT_ADAPTER_LEGACY		0
> +#define   TBT_ADAPTER_TBT3		1
> +#define TBT_INTEL_SPECIFIC_B0		BIT(26)
> +#define TBT_VENDOR_SPECIFIC_B0		BIT(30)
> +#define TBT_VENDOR_SPECIFIC_B1		BIT(31)
> +
> +/* TBT3 Cable Discover Mode VDO bits */
> +#define TBT_CABLE_SPEED(_vdo_)		(((_vdo_) & GENMASK(18, 16)) >> 16)
> +#define   TBT_CABLE_USB3_GEN1		1
> +#define   TBT_CABLE_USB3_PASSIVE	2
> +#define   TBT_CABLE_10_AND_20GBPS	3
> +#define TBT_CABLE_ROUNDED		BIT(19)
> +#define TBT_CABLE_OPTICAL		BIT(21)
> +#define TBT_CABLE_RETIMER		BIT(22)
> +#define TBT_CABLE_LINK_TRAINING		BIT(23)
> +
> +/* TBT3 Device Enter Mode VDO bits */
> +#define TBT_ENTER_MODE_CABLE_SPEED(_s_)	(((_s_) & GENMASK(2, 0)) << 16)
> +#define TBT_ENTER_MODE_ACTIVE_CABLE	BIT(24)

I guess my original RFC was before the introduction of
linux/usb/typec_tbt.h. You can replace all the above definitions with:

#include <linux/usb/typec_tbt.h>

> +enum tbt_state {
> +	TBT_STATE_IDLE,
> +	TBT_STATE_SOP_P_ENTER,
> +	TBT_STATE_SOP_PP_ENTER,
> +	TBT_STATE_ENTER,
> +	TBT_STATE_EXIT,
> +	TBT_STATE_SOP_PP_EXIT,
> +	TBT_STATE_SOP_P_EXIT
> +};
> +
> +struct tbt_altmode {
> +	enum tbt_state state;
> +	struct typec_cable *cable;
> +	struct typec_altmode *alt;
> +	struct typec_altmode *plug[2];

You really have to supply struct typec_thunderbolt_data from this
driver.

I understand that by leaving the mux handling to the alt mode drivers,
you have to refactor at least cros_ec_typec.c, but I really think you
have to do it. So please either add here:

        struct typec_thunderbolt_data data;

or if we don't need to store it, store only the Enter Mode VDO:

        u32 enter_vdo;

> +	struct work_struct work;
> +	struct mutex lock; /* device lock */
> +};
> +
> +static bool tbt_ready(struct typec_altmode *alt);
> +
> +static int tbt_enter_mode(struct tbt_altmode *tbt)
> +{
> +	struct typec_altmode *plug = tbt->plug[TYPEC_PLUG_SOP_P];
> +	u32 vdo;
> +
> +	vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
> +	vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
> +	vdo |= TBT_MODE;
> +
> +	if (plug) {
> +		if (typec_cable_is_active(tbt->cable))
> +			vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
> +
> +		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
> +		vdo |= plug->vdo & TBT_CABLE_ROUNDED;

TBT_CABLE_ROUNDED needs to be defined in typec_tbt.h. It's missing for
some reason.

> +		vdo |= plug->vdo & TBT_CABLE_OPTICAL;
> +		vdo |= plug->vdo & TBT_CABLE_RETIMER;
> +		vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
> +	} else {
> +		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
> +	}

So this vdo I believe will need to be stored:

        tbt->data.enter_vdo;

or

        tbt->enter_vdo = vdo;

> +	return typec_altmode_enter(tbt->alt, &vdo);
> +}
> +
> +static void tbt_altmode_work(struct work_struct *work)
> +{
> +	struct tbt_altmode *tbt = container_of(work, struct tbt_altmode, work);
> +	int ret;
> +
> +	mutex_lock(&tbt->lock);
> +
> +	switch (tbt->state) {
> +	case TBT_STATE_SOP_P_ENTER:
> +		ret = typec_altmode_enter(tbt->plug[TYPEC_PLUG_SOP_P], NULL);
> +		if (ret)
> +			dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_P]->dev,
> +				"failed to enter mode (%d)\n", ret);
> +		break;
> +	case TBT_STATE_SOP_PP_ENTER:
> +		ret = typec_altmode_enter(tbt->plug[TYPEC_PLUG_SOP_PP], NULL);
> +		if (ret)
> +			dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_PP]->dev,
> +				"failed to enter mode (%d)\n", ret);
> +		break;
> +	case TBT_STATE_ENTER:
> +		ret = tbt_enter_mode(tbt);
> +		if (ret)
> +			dev_dbg(&tbt->alt->dev, "failed to enter mode (%d)\n",
> +				ret);
> +		break;
> +	case TBT_STATE_EXIT:
> +		typec_altmode_exit(tbt->alt);
> +		break;
> +	case TBT_STATE_SOP_PP_EXIT:
> +		typec_altmode_exit(tbt->plug[TYPEC_PLUG_SOP_PP]);
> +		break;
> +	case TBT_STATE_SOP_P_EXIT:
> +		typec_altmode_exit(tbt->plug[TYPEC_PLUG_SOP_P]);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	tbt->state = TBT_STATE_IDLE;
> +
> +	mutex_unlock(&tbt->lock);
> +}
> +
> +static int tbt_altmode_vdm(struct typec_altmode *alt,
> +			   const u32 hdr, const u32 *vdo, int count)
> +{
> +	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
> +	int cmd_type = PD_VDO_CMDT(hdr);
> +	int cmd = PD_VDO_CMD(hdr);
> +
> +	mutex_lock(&tbt->lock);
> +
> +	if (tbt->state != TBT_STATE_IDLE) {
> +		mutex_unlock(&tbt->lock);
> +		return -EBUSY;
> +	}
> +
> +	switch (cmd_type) {
> +	case CMDT_RSP_ACK:
> +		switch (cmd) {
> +		case CMD_ENTER_MODE:
> +			/*
> +			 * Following the order describeded in USB Type-C Spec
> +			 * R2.0 Section 6.7.3.
> +			 */
> +			if (alt == tbt->plug[TYPEC_PLUG_SOP_P]) {
> +				if (tbt->plug[TYPEC_PLUG_SOP_PP])
> +					tbt->state = TBT_STATE_SOP_PP_ENTER;
> +				else
> +					tbt->state = TBT_STATE_ENTER;
> +			} else if (alt == tbt->plug[TYPEC_PLUG_SOP_PP]) {
> +				tbt->state = TBT_STATE_ENTER;
> +			} else {
> +				typec_altmode_notify(alt, TYPEC_STATE_MODAL,
> +						     NULL);

                                typec_altmode_notify(alt, TYPEC_STATE_MODAL, &tbt->data);

or, if this is possible:

                                struct typec_thunderbolt_data;

                                data.device_vdo = tbt->alt->vdo;
                                data.cable_vdo = tbt->plug[TYPEC_PLUG_SOP_P].vdo;
                                data.enter_vdo = tbt->enter_vdo;

                                typec_altmode_notify(alt, TYPEC_STATE_MODAL, &data);

> +			}
> +			break;
> +		case CMD_EXIT_MODE:
> +			if (alt == tbt->alt) {
> +				if (tbt->plug[TYPEC_PLUG_SOP_PP])
> +					tbt->state = TBT_STATE_SOP_PP_EXIT;
> +				else if (tbt->plug[TYPEC_PLUG_SOP_P])
> +					tbt->state = TBT_STATE_SOP_P_EXIT;
> +			} else if (alt == tbt->plug[TYPEC_PLUG_SOP_PP]) {
> +				tbt->state = TBT_STATE_SOP_P_EXIT;
> +			}
> +			break;
> +		}
> +		break;
> +	case CMDT_RSP_NAK:
> +		switch (cmd) {
> +		case CMD_ENTER_MODE:
> +			dev_warn(&alt->dev, "Enter Mode refused\n");
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	if (tbt->state != TBT_STATE_IDLE)
> +		schedule_work(&tbt->work);
> +
> +	mutex_unlock(&tbt->lock);
> +
> +	return 0;
> +}
> +
> +static int tbt_altmode_activate(struct typec_altmode *alt, int activate)
> +{
> +	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
> +	int ret;
> +
> +	mutex_lock(&tbt->lock);
> +
> +	if (!tbt_ready(alt))
> +		return -ENODEV;
> +
> +	/* Preventing the user space from entering/exiting the cable alt mode */
> +	if (alt != tbt->alt)
> +		ret = -EPERM;
> +	else if (activate)
> +		ret = tbt_enter_mode(tbt);
> +	else
> +		ret = typec_altmode_exit(alt);
> +
> +	mutex_unlock(&tbt->lock);
> +
> +	return ret;
> +}
> +
> +static const struct typec_altmode_ops tbt_altmode_ops = {
> +	.vdm		= tbt_altmode_vdm,
> +	.activate	= tbt_altmode_activate
> +};
> +
> +static int tbt_altmode_probe(struct typec_altmode *alt)
> +{
> +	struct tbt_altmode *tbt;
> +
> +	tbt = devm_kzalloc(&alt->dev, sizeof(*tbt), GFP_KERNEL);
> +	if (!tbt)
> +		return -ENOMEM;
> +
> +	INIT_WORK(&tbt->work, tbt_altmode_work);
> +	mutex_init(&tbt->lock);
> +	tbt->alt = alt;

        tbt->data.device_mode = alt->vdo;

> +	alt->desc = "Thunderbolt3";
> +	typec_altmode_set_drvdata(alt, tbt);
> +	typec_altmode_set_ops(alt, &tbt_altmode_ops);
> +
> +	if (tbt_ready(alt)) {
> +		if (tbt->plug[TYPEC_PLUG_SOP_PP])
> +			tbt->state = TBT_STATE_SOP_PP_ENTER;
> +		else if (tbt->plug[TYPEC_PLUG_SOP_P])
> +			tbt->state = TBT_STATE_SOP_P_ENTER;
> +		else
> +			tbt->state = TBT_STATE_ENTER;
> +		schedule_work(&tbt->work);
> +	}
> +
> +	return 0;
> +}
> +
> +static void tbt_altmode_remove(struct typec_altmode *alt)
> +{
> +	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
> +
> +	for (int i = TYPEC_PLUG_SOP_PP; i > 0; --i) {
> +		if (tbt->plug[i])
> +			typec_altmode_put_plug(tbt->plug[i]);
> +	}
> +
> +	if (tbt->cable)
> +		typec_cable_put(tbt->cable);
> +}
> +
> +static bool tbt_ready(struct typec_altmode *alt)
> +{
> +	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
> +	struct typec_altmode *plug;
> +
> +	if (tbt->cable)
> +		return true;
> +
> +	/* Thundebolt 3 requires a cable with eMarker */
> +	tbt->cable = typec_cable_get(typec_altmode2port(tbt->alt));
> +	if (!tbt->cable)
> +		return false;
> +
> +	/* We accept systems without SOP' or SOP''. This means the port altmode
> +	 * driver will be responsible for properly ordering entry/exit.
> +	 */
> +	for (int i = 0; i < TYPEC_PLUG_SOP_PP + 1; i++) {
> +		plug = typec_altmode_get_plug(tbt->alt, i);
> +		if (IS_ERR(plug))
> +			continue;
> +
> +		if (!plug || plug->svid != USB_TYPEC_VENDOR_INTEL)
> +			break;
> +
> +		plug->desc = "Thunderbolt3";
> +		plug->ops = &tbt_altmode_ops;
> +		typec_altmode_set_drvdata(plug, tbt);
> +
> +		tbt->plug[i] = plug;
> +	}

        tbt->data.cable_mode = tbt->plug[TYPEC_PLUG_SOP_P].vdo;

> +	return true;
> +}
> +
> +static const struct typec_device_id tbt_typec_id[] = {
> +	{ USB_TYPEC_VENDOR_INTEL, TYPEC_ANY_MODE },

There is also the alias: USB_TYPEC_TBT_SID

> +	{ }
> +};
> +MODULE_DEVICE_TABLE(typec, tbt_typec_id);
> +
> +static struct typec_altmode_driver tbt_altmode_driver = {
> +	.id_table = tbt_typec_id,
> +	.probe = tbt_altmode_probe,
> +	.remove = tbt_altmode_remove,
> +	.driver = {
> +		.name = "typec-thunderbolt",
> +		.owner = THIS_MODULE,
> +	}
> +};
> +module_typec_altmode_driver(tbt_altmode_driver);
> +
> +MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Thunderbolt3 USB Type-C Alternate Mode");

thanks,
kernel test robot Sept. 26, 2024, 3:14 p.m. UTC | #2
Hi Abhishek,

kernel test robot noticed the following build warnings:

[auto build test WARNING on chrome-platform/for-next]
[also build test WARNING on chrome-platform/for-firmware-next usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.11 next-20240926]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Abhishek-Pandit-Subedi/usb-typec-Add-driver-for-Thunderbolt-3-Alternate-Mode/20240926-002931
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git for-next
patch link:    https://lore.kernel.org/r/20240925092505.1.I3080b036e8de0b9957c57c1c3059db7149c5e549%40changeid
patch subject: [PATCH 1/8] usb: typec: Add driver for Thunderbolt 3 Alternate Mode
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20240926/202409262224.Bnlmjakc-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240926/202409262224.Bnlmjakc-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409262224.Bnlmjakc-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/usb/typec/altmodes/thunderbolt.c:15: warning: expecting prototype for USB Typec(). Prototype was for USB_TYPEC_VENDOR_INTEL() instead


vim +15 drivers/usb/typec/altmodes/thunderbolt.c

    14	
  > 15	#define USB_TYPEC_VENDOR_INTEL		0x8087
    16
diff mbox series

Patch

diff --git a/drivers/usb/typec/altmodes/Kconfig b/drivers/usb/typec/altmodes/Kconfig
index 1a6b5e872b0d..7867fa7c405d 100644
--- a/drivers/usb/typec/altmodes/Kconfig
+++ b/drivers/usb/typec/altmodes/Kconfig
@@ -23,4 +23,13 @@  config TYPEC_NVIDIA_ALTMODE
 	  To compile this driver as a module, choose M here: the
 	  module will be called typec_nvidia.
 
+config TYPEC_TBT_ALTMODE
+	tristate "Thunderbolt3 Alternate Mode driver"
+	help
+	  Select this option if you have Thunderbolt3 hardware on your
+	  system.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called typec_thunderbolt.
+
 endmenu
diff --git a/drivers/usb/typec/altmodes/Makefile b/drivers/usb/typec/altmodes/Makefile
index 45717548b396..508a68351bd2 100644
--- a/drivers/usb/typec/altmodes/Makefile
+++ b/drivers/usb/typec/altmodes/Makefile
@@ -4,3 +4,5 @@  obj-$(CONFIG_TYPEC_DP_ALTMODE)		+= typec_displayport.o
 typec_displayport-y			:= displayport.o
 obj-$(CONFIG_TYPEC_NVIDIA_ALTMODE)	+= typec_nvidia.o
 typec_nvidia-y				:= nvidia.o
+obj-$(CONFIG_TYPEC_TBT_ALTMODE)		+= typec_thunderbolt.o
+typec_thunderbolt-y			:= thunderbolt.o
diff --git a/drivers/usb/typec/altmodes/thunderbolt.c b/drivers/usb/typec/altmodes/thunderbolt.c
new file mode 100644
index 000000000000..515e775ee41a
--- /dev/null
+++ b/drivers/usb/typec/altmodes/thunderbolt.c
@@ -0,0 +1,321 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * USB Typec-C Thuderbolt3 Alternate Mode driver
+ *
+ * Copyright (C) 2019 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/usb/pd_vdo.h>
+#include <linux/usb/typec_altmode.h>
+
+#define USB_TYPEC_VENDOR_INTEL		0x8087
+
+/* TBT3 Device Discover Mode VDO bits */
+#define TBT_MODE			BIT(0)
+#define TBT_ADAPTER(_vdo_)		(((_vdo_) & BIT(16)) >> 16)
+#define   TBT_ADAPTER_LEGACY		0
+#define   TBT_ADAPTER_TBT3		1
+#define TBT_INTEL_SPECIFIC_B0		BIT(26)
+#define TBT_VENDOR_SPECIFIC_B0		BIT(30)
+#define TBT_VENDOR_SPECIFIC_B1		BIT(31)
+
+/* TBT3 Cable Discover Mode VDO bits */
+#define TBT_CABLE_SPEED(_vdo_)		(((_vdo_) & GENMASK(18, 16)) >> 16)
+#define   TBT_CABLE_USB3_GEN1		1
+#define   TBT_CABLE_USB3_PASSIVE	2
+#define   TBT_CABLE_10_AND_20GBPS	3
+#define TBT_CABLE_ROUNDED		BIT(19)
+#define TBT_CABLE_OPTICAL		BIT(21)
+#define TBT_CABLE_RETIMER		BIT(22)
+#define TBT_CABLE_LINK_TRAINING		BIT(23)
+
+/* TBT3 Device Enter Mode VDO bits */
+#define TBT_ENTER_MODE_CABLE_SPEED(_s_)	(((_s_) & GENMASK(2, 0)) << 16)
+#define TBT_ENTER_MODE_ACTIVE_CABLE	BIT(24)
+
+enum tbt_state {
+	TBT_STATE_IDLE,
+	TBT_STATE_SOP_P_ENTER,
+	TBT_STATE_SOP_PP_ENTER,
+	TBT_STATE_ENTER,
+	TBT_STATE_EXIT,
+	TBT_STATE_SOP_PP_EXIT,
+	TBT_STATE_SOP_P_EXIT
+};
+
+struct tbt_altmode {
+	enum tbt_state state;
+	struct typec_cable *cable;
+	struct typec_altmode *alt;
+	struct typec_altmode *plug[2];
+
+	struct work_struct work;
+	struct mutex lock; /* device lock */
+};
+
+static bool tbt_ready(struct typec_altmode *alt);
+
+static int tbt_enter_mode(struct tbt_altmode *tbt)
+{
+	struct typec_altmode *plug = tbt->plug[TYPEC_PLUG_SOP_P];
+	u32 vdo;
+
+	vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
+	vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
+	vdo |= TBT_MODE;
+
+	if (plug) {
+		if (typec_cable_is_active(tbt->cable))
+			vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
+
+		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
+		vdo |= plug->vdo & TBT_CABLE_ROUNDED;
+		vdo |= plug->vdo & TBT_CABLE_OPTICAL;
+		vdo |= plug->vdo & TBT_CABLE_RETIMER;
+		vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
+	} else {
+		vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
+	}
+
+	return typec_altmode_enter(tbt->alt, &vdo);
+}
+
+static void tbt_altmode_work(struct work_struct *work)
+{
+	struct tbt_altmode *tbt = container_of(work, struct tbt_altmode, work);
+	int ret;
+
+	mutex_lock(&tbt->lock);
+
+	switch (tbt->state) {
+	case TBT_STATE_SOP_P_ENTER:
+		ret = typec_altmode_enter(tbt->plug[TYPEC_PLUG_SOP_P], NULL);
+		if (ret)
+			dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_P]->dev,
+				"failed to enter mode (%d)\n", ret);
+		break;
+	case TBT_STATE_SOP_PP_ENTER:
+		ret = typec_altmode_enter(tbt->plug[TYPEC_PLUG_SOP_PP], NULL);
+		if (ret)
+			dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_PP]->dev,
+				"failed to enter mode (%d)\n", ret);
+		break;
+	case TBT_STATE_ENTER:
+		ret = tbt_enter_mode(tbt);
+		if (ret)
+			dev_dbg(&tbt->alt->dev, "failed to enter mode (%d)\n",
+				ret);
+		break;
+	case TBT_STATE_EXIT:
+		typec_altmode_exit(tbt->alt);
+		break;
+	case TBT_STATE_SOP_PP_EXIT:
+		typec_altmode_exit(tbt->plug[TYPEC_PLUG_SOP_PP]);
+		break;
+	case TBT_STATE_SOP_P_EXIT:
+		typec_altmode_exit(tbt->plug[TYPEC_PLUG_SOP_P]);
+		break;
+	default:
+		break;
+	}
+
+	tbt->state = TBT_STATE_IDLE;
+
+	mutex_unlock(&tbt->lock);
+}
+
+static int tbt_altmode_vdm(struct typec_altmode *alt,
+			   const u32 hdr, const u32 *vdo, int count)
+{
+	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+	int cmd_type = PD_VDO_CMDT(hdr);
+	int cmd = PD_VDO_CMD(hdr);
+
+	mutex_lock(&tbt->lock);
+
+	if (tbt->state != TBT_STATE_IDLE) {
+		mutex_unlock(&tbt->lock);
+		return -EBUSY;
+	}
+
+	switch (cmd_type) {
+	case CMDT_RSP_ACK:
+		switch (cmd) {
+		case CMD_ENTER_MODE:
+			/*
+			 * Following the order describeded in USB Type-C Spec
+			 * R2.0 Section 6.7.3.
+			 */
+			if (alt == tbt->plug[TYPEC_PLUG_SOP_P]) {
+				if (tbt->plug[TYPEC_PLUG_SOP_PP])
+					tbt->state = TBT_STATE_SOP_PP_ENTER;
+				else
+					tbt->state = TBT_STATE_ENTER;
+			} else if (alt == tbt->plug[TYPEC_PLUG_SOP_PP]) {
+				tbt->state = TBT_STATE_ENTER;
+			} else {
+				typec_altmode_notify(alt, TYPEC_STATE_MODAL,
+						     NULL);
+			}
+			break;
+		case CMD_EXIT_MODE:
+			if (alt == tbt->alt) {
+				if (tbt->plug[TYPEC_PLUG_SOP_PP])
+					tbt->state = TBT_STATE_SOP_PP_EXIT;
+				else if (tbt->plug[TYPEC_PLUG_SOP_P])
+					tbt->state = TBT_STATE_SOP_P_EXIT;
+			} else if (alt == tbt->plug[TYPEC_PLUG_SOP_PP]) {
+				tbt->state = TBT_STATE_SOP_P_EXIT;
+			}
+			break;
+		}
+		break;
+	case CMDT_RSP_NAK:
+		switch (cmd) {
+		case CMD_ENTER_MODE:
+			dev_warn(&alt->dev, "Enter Mode refused\n");
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	if (tbt->state != TBT_STATE_IDLE)
+		schedule_work(&tbt->work);
+
+	mutex_unlock(&tbt->lock);
+
+	return 0;
+}
+
+static int tbt_altmode_activate(struct typec_altmode *alt, int activate)
+{
+	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+	int ret;
+
+	mutex_lock(&tbt->lock);
+
+	if (!tbt_ready(alt))
+		return -ENODEV;
+
+	/* Preventing the user space from entering/exiting the cable alt mode */
+	if (alt != tbt->alt)
+		ret = -EPERM;
+	else if (activate)
+		ret = tbt_enter_mode(tbt);
+	else
+		ret = typec_altmode_exit(alt);
+
+	mutex_unlock(&tbt->lock);
+
+	return ret;
+}
+
+static const struct typec_altmode_ops tbt_altmode_ops = {
+	.vdm		= tbt_altmode_vdm,
+	.activate	= tbt_altmode_activate
+};
+
+static int tbt_altmode_probe(struct typec_altmode *alt)
+{
+	struct tbt_altmode *tbt;
+
+	tbt = devm_kzalloc(&alt->dev, sizeof(*tbt), GFP_KERNEL);
+	if (!tbt)
+		return -ENOMEM;
+
+	INIT_WORK(&tbt->work, tbt_altmode_work);
+	mutex_init(&tbt->lock);
+	tbt->alt = alt;
+
+	alt->desc = "Thunderbolt3";
+	typec_altmode_set_drvdata(alt, tbt);
+	typec_altmode_set_ops(alt, &tbt_altmode_ops);
+
+	if (tbt_ready(alt)) {
+		if (tbt->plug[TYPEC_PLUG_SOP_PP])
+			tbt->state = TBT_STATE_SOP_PP_ENTER;
+		else if (tbt->plug[TYPEC_PLUG_SOP_P])
+			tbt->state = TBT_STATE_SOP_P_ENTER;
+		else
+			tbt->state = TBT_STATE_ENTER;
+		schedule_work(&tbt->work);
+	}
+
+	return 0;
+}
+
+static void tbt_altmode_remove(struct typec_altmode *alt)
+{
+	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+
+	for (int i = TYPEC_PLUG_SOP_PP; i > 0; --i) {
+		if (tbt->plug[i])
+			typec_altmode_put_plug(tbt->plug[i]);
+	}
+
+	if (tbt->cable)
+		typec_cable_put(tbt->cable);
+}
+
+static bool tbt_ready(struct typec_altmode *alt)
+{
+	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+	struct typec_altmode *plug;
+
+	if (tbt->cable)
+		return true;
+
+	/* Thundebolt 3 requires a cable with eMarker */
+	tbt->cable = typec_cable_get(typec_altmode2port(tbt->alt));
+	if (!tbt->cable)
+		return false;
+
+	/* We accept systems without SOP' or SOP''. This means the port altmode
+	 * driver will be responsible for properly ordering entry/exit.
+	 */
+	for (int i = 0; i < TYPEC_PLUG_SOP_PP + 1; i++) {
+		plug = typec_altmode_get_plug(tbt->alt, i);
+		if (IS_ERR(plug))
+			continue;
+
+		if (!plug || plug->svid != USB_TYPEC_VENDOR_INTEL)
+			break;
+
+		plug->desc = "Thunderbolt3";
+		plug->ops = &tbt_altmode_ops;
+		typec_altmode_set_drvdata(plug, tbt);
+
+		tbt->plug[i] = plug;
+	}
+
+	return true;
+}
+
+static const struct typec_device_id tbt_typec_id[] = {
+	{ USB_TYPEC_VENDOR_INTEL, TYPEC_ANY_MODE },
+	{ }
+};
+MODULE_DEVICE_TABLE(typec, tbt_typec_id);
+
+static struct typec_altmode_driver tbt_altmode_driver = {
+	.id_table = tbt_typec_id,
+	.probe = tbt_altmode_probe,
+	.remove = tbt_altmode_remove,
+	.driver = {
+		.name = "typec-thunderbolt",
+		.owner = THIS_MODULE,
+	}
+};
+module_typec_altmode_driver(tbt_altmode_driver);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Thunderbolt3 USB Type-C Alternate Mode");