drivers/misc/mei/pxp/mei_pxp.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright © 2020 - 2021 Intel Corporation
  */

 /**
  * DOC: MEI_PXP Client Driver
  *
  * The mei_pxp driver acts as a translation layer between PXP
  * protocol  implementer (I915) and ME FW by translating PXP
  * negotiation messages to ME FW command payloads and vice versa.
  */

 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mei.h>
 #include <linux/mei_cl_bus.h>
 #include <linux/component.h>
 #include <drm/drm_connector.h>
 #include <drm/i915_component.h>
 #include <drm/i915_pxp_tee_interface.h>

 #include "mei_pxp.h"

 static inline int mei_pxp_reenable(const struct device *dev, struct mei_cl_device *cldev)
 {
 	int ret;

 	dev_warn(dev, "Trying to reset the channel...\n");
 	ret = mei_cldev_disable(cldev);
 	if (ret < 0)
 		dev_warn(dev, "mei_cldev_disable failed. %d\n", ret);
 	/*
 	 * Explicitly ignoring disable failure,
 	 * enable may fix the states and succeed
 	 */
 	ret = mei_cldev_enable(cldev);
 	if (ret < 0)
 		dev_err(dev, "mei_cldev_enable failed. %d\n", ret);
 	return ret;
 }

 /**
  * mei_pxp_send_message() - Sends a PXP message to ME FW.
  * @dev: device corresponding to the mei_cl_device
  * @message: a message buffer to send
  * @size: size of the message
  * @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
  *
  * Returns: 0 on Success, <0 on Failure with the following defined failures.
  *         -ENODEV: Client was not connected.
  *                  Caller may attempt to try again immediately.
  *         -ENOMEM: Internal memory allocation failure experienced.
  *                  Caller may sleep to allow kernel reclaim before retrying.
  *         -EINTR : Calling thread received a signal. Caller may choose
  *                  to abandon with the same thread id.
  *         -ETIME : Request is timed out.
  *                  Caller may attempt to try again immediately.
  */
 static int
 mei_pxp_send_message(struct device *dev, const void *message, size_t size, unsigned long timeout_ms)
 {
 	struct mei_cl_device *cldev;
 	ssize_t byte;
 	int ret;

 	if (!dev || !message)
 		return -EINVAL;

 	cldev = to_mei_cl_device(dev);

 	byte = mei_cldev_send_timeout(cldev, message, size, timeout_ms);
 	if (byte < 0) {
 		dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte);
 		switch (byte) {
 		case -ENOMEM:
 			fallthrough;
 		case -ENODEV:
 			fallthrough;
 		case -ETIME:
 			ret = mei_pxp_reenable(dev, cldev);
 			if (ret)
 				byte = ret;
 			break;
 		}
 		return byte;
 	}

 	return 0;
 }

 /**
  * mei_pxp_receive_message() - Receives a PXP message from ME FW.
  * @dev: device corresponding to the mei_cl_device
  * @buffer: a message buffer to contain the received message
  * @size: size of the buffer
  * @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
  *
  * Returns: number of bytes send on Success, <0 on Failure with the following defined failures.
  *         -ENODEV: Client was not connected.
  *                  Caller may attempt to try again from send immediately.
  *         -ENOMEM: Internal memory allocation failure experienced.
  *                  Caller may sleep to allow kernel reclaim before retrying.
  *         -EINTR : Calling thread received a signal. Caller will need to repeat calling
  *                  (with a different owning thread) to retrieve existing unclaimed response
  *                  (and may discard it).
  *         -ETIME : Request is timed out.
  *                  Caller may attempt to try again from send immediately.
  */
 static int
 mei_pxp_receive_message(struct device *dev, void *buffer, size_t size, unsigned long timeout_ms)
 {
 	struct mei_cl_device *cldev;
 	ssize_t byte;
 	bool retry = false;
 	int ret;

 	if (!dev || !buffer)
 		return -EINVAL;

 	cldev = to_mei_cl_device(dev);

 retry:
 	byte = mei_cldev_recv_timeout(cldev, buffer, size, timeout_ms);
 	if (byte < 0) {
 		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
 		switch (byte) {
 		case -ENOMEM:
 			/* Retry the read when pages are reclaimed */
 			msleep(20);
 			if (!retry) {
 				retry = true;
 				goto retry;
 			}
 			fallthrough;
 		case -ENODEV:
 			fallthrough;
 		case -ETIME:
 			ret = mei_pxp_reenable(dev, cldev);
 			if (ret)
 				byte = ret;
 			break;
 		}
 	}

 	return byte;
 }

 /**
  * mei_pxp_gsc_command() - sends a gsc command, by sending
  * a sgl mei message to gsc and receiving reply from gsc
  *
  * @dev: device corresponding to the mei_cl_device
  * @client_id: client id to send the command to
  * @fence_id: fence id to send the command to
  * @sg_in: scatter gather list containing addresses for rx message buffer
  * @total_in_len: total length of data in 'in' sg, can be less than the sum of buffers sizes
  * @sg_out: scatter gather list containing addresses for tx message buffer
  *
  * Return: bytes sent on Success, <0 on Failure
  */
 static ssize_t mei_pxp_gsc_command(struct device *dev, u8 client_id, u32 fence_id,
 				   struct scatterlist *sg_in, size_t total_in_len,
 				   struct scatterlist *sg_out)
 {
 	struct mei_cl_device *cldev;

 	cldev = to_mei_cl_device(dev);

 	return mei_cldev_send_gsc_command(cldev, client_id, fence_id, sg_in, total_in_len, sg_out);
 }

 static const struct i915_pxp_component_ops mei_pxp_ops = {
 	.owner = THIS_MODULE,
 	.send = mei_pxp_send_message,
 	.recv = mei_pxp_receive_message,
 	.gsc_command = mei_pxp_gsc_command,
 };

 static int mei_component_master_bind(struct device *dev)
 {
 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
 	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
 	int ret;

 	comp_master->ops = &mei_pxp_ops;
 	comp_master->tee_dev = dev;
 	ret = component_bind_all(dev, comp_master);
 	if (ret < 0)
 		return ret;

 	return 0;
 }

 static void mei_component_master_unbind(struct device *dev)
 {
 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
 	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);

 	component_unbind_all(dev, comp_master);
 }

 static const struct component_master_ops mei_component_master_ops = {
 	.bind = mei_component_master_bind,
 	.unbind = mei_component_master_unbind,
 };

 /**
  * mei_pxp_component_match - compare function for matching mei pxp.
  *
  *    The function checks if the driver is i915, the subcomponent is PXP
  *    and the grand parent of pxp and the parent of i915 are the same
  *    PCH device.
  *
  * @dev: master device
  * @subcomponent: subcomponent to match (I915_COMPONENT_PXP)
  * @data: compare data (mei pxp device)
  *
  * Return:
  * * 1 - if components match
  * * 0 - otherwise
  */
 static int mei_pxp_component_match(struct device *dev, int subcomponent,
 				   void *data)
 {
 	struct device *base = data;

 	if (!dev)
 		return 0;

 	if (!dev->driver || strcmp(dev->driver->name, "i915") ||
 	    subcomponent != I915_COMPONENT_PXP)
 		return 0;

 	base = base->parent;
 	if (!base) /* mei device */
 		return 0;

 	base = base->parent; /* pci device */
 	/* for dgfx */
 	if (base && dev == base)
 		return 1;

 	/* for pch */
 	dev = dev->parent;
 	return (base && dev && dev == base);
 }

 static int mei_pxp_probe(struct mei_cl_device *cldev,
 			 const struct mei_cl_device_id *id)
 {
 	struct i915_pxp_component *comp_master;
 	struct component_match *master_match;
 	int ret;

 	ret = mei_cldev_enable(cldev);
 	if (ret < 0) {
 		dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
 		goto enable_err_exit;
 	}

 	comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL);
 	if (!comp_master) {
 		ret = -ENOMEM;
 		goto err_exit;
 	}

 	master_match = NULL;
 	component_match_add_typed(&cldev->dev, &master_match,
 				  mei_pxp_component_match, &cldev->dev);
 	if (IS_ERR_OR_NULL(master_match)) {
 		ret = -ENOMEM;
 		goto err_exit;
 	}

 	mei_cldev_set_drvdata(cldev, comp_master);
 	ret = component_master_add_with_match(&cldev->dev,
 					      &mei_component_master_ops,
 					      master_match);
 	if (ret < 0) {
 		dev_err(&cldev->dev, "Master comp add failed %d\n", ret);
 		goto err_exit;
 	}

 	return 0;

 err_exit:
 	mei_cldev_set_drvdata(cldev, NULL);
 	kfree(comp_master);
 	mei_cldev_disable(cldev);
 enable_err_exit:
 	return ret;
 }

 static void mei_pxp_remove(struct mei_cl_device *cldev)
 {
 	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
 	int ret;

 	component_master_del(&cldev->dev, &mei_component_master_ops);
 	kfree(comp_master);
 	mei_cldev_set_drvdata(cldev, NULL);

 	ret = mei_cldev_disable(cldev);
 	if (ret)
 		dev_warn(&cldev->dev, "mei_cldev_disable() failed\n");
 }

 /* fbf6fcf1-96cf-4e2e-a6a6-1bab8cbe36b1 : PAVP GUID*/
 #define MEI_GUID_PXP UUID_LE(0xfbf6fcf1, 0x96cf, 0x4e2e, 0xA6, \
 			     0xa6, 0x1b, 0xab, 0x8c, 0xbe, 0x36, 0xb1)

 static struct mei_cl_device_id mei_pxp_tbl[] = {
 	{ .uuid = MEI_GUID_PXP, .version = MEI_CL_VERSION_ANY },
 	{ }
 };
 MODULE_DEVICE_TABLE(mei, mei_pxp_tbl);

 static struct mei_cl_driver mei_pxp_driver = {
 	.id_table = mei_pxp_tbl,
 	.name = KBUILD_MODNAME,
 	.probe = mei_pxp_probe,
 	.remove	= mei_pxp_remove,
 };

 module_mei_cl_driver(mei_pxp_driver);

 MODULE_AUTHOR("Intel Corporation");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MEI PXP");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright © 2020 - 2021 Intel Corporation
	*/

	/**
	* DOC: MEI_PXP Client Driver
	*
	* The mei_pxp driver acts as a translation layer between PXP
	* protocol implementer (I915) and ME FW by translating PXP
	* negotiation messages to ME FW command payloads and vice versa.
	*/

	#include <linux/delay.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/mei.h>
	#include <linux/mei_cl_bus.h>
	#include <linux/component.h>
	#include <drm/drm_connector.h>
	#include <drm/i915_component.h>
	#include <drm/i915_pxp_tee_interface.h>

	#include "mei_pxp.h"

	static inline int mei_pxp_reenable(const struct device dev, struct mei_cl_device cldev)
	{
	int ret;

	dev_warn(dev, "Trying to reset the channel...\n");
	ret = mei_cldev_disable(cldev);
	if (ret < 0)
	dev_warn(dev, "mei_cldev_disable failed. %d\n", ret);
	/*
	* Explicitly ignoring disable failure,
	* enable may fix the states and succeed
	*/
	ret = mei_cldev_enable(cldev);
	if (ret < 0)
	dev_err(dev, "mei_cldev_enable failed. %d\n", ret);
	return ret;
	}

	/**
	* mei_pxp_send_message() - Sends a PXP message to ME FW.
	* @dev: device corresponding to the mei_cl_device
	* @message: a message buffer to send
	* @size: size of the message
	* @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
	*
	* Returns: 0 on Success, <0 on Failure with the following defined failures.
	* -ENODEV: Client was not connected.
	* Caller may attempt to try again immediately.
	* -ENOMEM: Internal memory allocation failure experienced.
	* Caller may sleep to allow kernel reclaim before retrying.
	* -EINTR : Calling thread received a signal. Caller may choose
	* to abandon with the same thread id.
	* -ETIME : Request is timed out.
	* Caller may attempt to try again immediately.
	*/
	static int
	mei_pxp_send_message(struct device dev, const void message, size_t size, unsigned long timeout_ms)
	{
	struct mei_cl_device *cldev;
	ssize_t byte;
	int ret;

	if (!dev \|\| !message)
	return -EINVAL;

	cldev = to_mei_cl_device(dev);

	byte = mei_cldev_send_timeout(cldev, message, size, timeout_ms);
	if (byte < 0) {
	dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte);
	switch (byte) {
	case -ENOMEM:
	fallthrough;
	case -ENODEV:
	fallthrough;
	case -ETIME:
	ret = mei_pxp_reenable(dev, cldev);
	if (ret)
	byte = ret;
	break;
	}
	return byte;
	}

	return 0;
	}

	/**
	* mei_pxp_receive_message() - Receives a PXP message from ME FW.
	* @dev: device corresponding to the mei_cl_device
	* @buffer: a message buffer to contain the received message
	* @size: size of the buffer
	* @timeout_ms: timeout in milliseconds, zero means wait indefinitely.
	*
	* Returns: number of bytes send on Success, <0 on Failure with the following defined failures.
	* -ENODEV: Client was not connected.
	* Caller may attempt to try again from send immediately.
	* -ENOMEM: Internal memory allocation failure experienced.
	* Caller may sleep to allow kernel reclaim before retrying.
	* -EINTR : Calling thread received a signal. Caller will need to repeat calling
	* (with a different owning thread) to retrieve existing unclaimed response
	* (and may discard it).
	* -ETIME : Request is timed out.
	* Caller may attempt to try again from send immediately.
	*/
	static int
	mei_pxp_receive_message(struct device dev, void buffer, size_t size, unsigned long timeout_ms)
	{
	struct mei_cl_device *cldev;
	ssize_t byte;
	bool retry = false;
	int ret;

	if (!dev \|\| !buffer)
	return -EINVAL;

	cldev = to_mei_cl_device(dev);

	retry:
	byte = mei_cldev_recv_timeout(cldev, buffer, size, timeout_ms);
	if (byte < 0) {
	dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
	switch (byte) {
	case -ENOMEM:
	/* Retry the read when pages are reclaimed */
	msleep(20);
	if (!retry) {
	retry = true;
	goto retry;
	}
	fallthrough;
	case -ENODEV:
	fallthrough;
	case -ETIME:
	ret = mei_pxp_reenable(dev, cldev);
	if (ret)
	byte = ret;
	break;
	}
	}

	return byte;
	}

	/**
	* mei_pxp_gsc_command() - sends a gsc command, by sending
	* a sgl mei message to gsc and receiving reply from gsc
	*
	* @dev: device corresponding to the mei_cl_device
	* @client_id: client id to send the command to
	* @fence_id: fence id to send the command to
	* @sg_in: scatter gather list containing addresses for rx message buffer
	* @total_in_len: total length of data in 'in' sg, can be less than the sum of buffers sizes
	* @sg_out: scatter gather list containing addresses for tx message buffer
	*
	* Return: bytes sent on Success, <0 on Failure
	*/
	static ssize_t mei_pxp_gsc_command(struct device *dev, u8 client_id, u32 fence_id,
	struct scatterlist *sg_in, size_t total_in_len,
	struct scatterlist *sg_out)
	{
	struct mei_cl_device *cldev;

	cldev = to_mei_cl_device(dev);

	return mei_cldev_send_gsc_command(cldev, client_id, fence_id, sg_in, total_in_len, sg_out);
	}

	static const struct i915_pxp_component_ops mei_pxp_ops = {
	.owner = THIS_MODULE,
	.send = mei_pxp_send_message,
	.recv = mei_pxp_receive_message,
	.gsc_command = mei_pxp_gsc_command,
	};

	static int mei_component_master_bind(struct device *dev)
	{
	struct mei_cl_device *cldev = to_mei_cl_device(dev);
	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
	int ret;

	comp_master->ops = &mei_pxp_ops;
	comp_master->tee_dev = dev;
	ret = component_bind_all(dev, comp_master);
	if (ret < 0)
	return ret;

	return 0;
	}

	static void mei_component_master_unbind(struct device *dev)
	{
	struct mei_cl_device *cldev = to_mei_cl_device(dev);
	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);

	component_unbind_all(dev, comp_master);
	}

	static const struct component_master_ops mei_component_master_ops = {
	.bind = mei_component_master_bind,
	.unbind = mei_component_master_unbind,
	};

	/**
	* mei_pxp_component_match - compare function for matching mei pxp.
	*
	* The function checks if the driver is i915, the subcomponent is PXP
	* and the grand parent of pxp and the parent of i915 are the same
	* PCH device.
	*
	* @dev: master device
	* @subcomponent: subcomponent to match (I915_COMPONENT_PXP)
	* @data: compare data (mei pxp device)
	*
	* Return:
	* * 1 - if components match
	* * 0 - otherwise
	*/
	static int mei_pxp_component_match(struct device *dev, int subcomponent,
	void *data)
	{
	struct device *base = data;

	if (!dev)
	return 0;

	if (!dev->driver \|\| strcmp(dev->driver->name, "i915") \|\|
	subcomponent != I915_COMPONENT_PXP)
	return 0;

	base = base->parent;
	if (!base) /* mei device */
	return 0;

	base = base->parent; /* pci device */
	/* for dgfx */
	if (base && dev == base)
	return 1;

	/* for pch */
	dev = dev->parent;
	return (base && dev && dev == base);
	}

	static int mei_pxp_probe(struct mei_cl_device *cldev,
	const struct mei_cl_device_id *id)
	{
	struct i915_pxp_component *comp_master;
	struct component_match *master_match;
	int ret;

	ret = mei_cldev_enable(cldev);
	if (ret < 0) {
	dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
	goto enable_err_exit;
	}

	comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL);
	if (!comp_master) {
	ret = -ENOMEM;
	goto err_exit;
	}

	master_match = NULL;
	component_match_add_typed(&cldev->dev, &master_match,
	mei_pxp_component_match, &cldev->dev);
	if (IS_ERR_OR_NULL(master_match)) {
	ret = -ENOMEM;
	goto err_exit;
	}

	mei_cldev_set_drvdata(cldev, comp_master);
	ret = component_master_add_with_match(&cldev->dev,
	&mei_component_master_ops,
	master_match);
	if (ret < 0) {
	dev_err(&cldev->dev, "Master comp add failed %d\n", ret);
	goto err_exit;
	}

	return 0;

	err_exit:
	mei_cldev_set_drvdata(cldev, NULL);
	kfree(comp_master);
	mei_cldev_disable(cldev);
	enable_err_exit:
	return ret;
	}

	static void mei_pxp_remove(struct mei_cl_device *cldev)
	{
	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
	int ret;

	component_master_del(&cldev->dev, &mei_component_master_ops);
	kfree(comp_master);
	mei_cldev_set_drvdata(cldev, NULL);

	ret = mei_cldev_disable(cldev);
	if (ret)
	dev_warn(&cldev->dev, "mei_cldev_disable() failed\n");
	}

	/* fbf6fcf1-96cf-4e2e-a6a6-1bab8cbe36b1 : PAVP GUID*/
	#define MEI_GUID_PXP UUID_LE(0xfbf6fcf1, 0x96cf, 0x4e2e, 0xA6, \
	0xa6, 0x1b, 0xab, 0x8c, 0xbe, 0x36, 0xb1)

	static struct mei_cl_device_id mei_pxp_tbl[] = {
	{ .uuid = MEI_GUID_PXP, .version = MEI_CL_VERSION_ANY },
	{ }
	};
	MODULE_DEVICE_TABLE(mei, mei_pxp_tbl);

	static struct mei_cl_driver mei_pxp_driver = {
	.id_table = mei_pxp_tbl,
	.name = KBUILD_MODNAME,
	.probe = mei_pxp_probe,
	.remove = mei_pxp_remove,
	};

	module_mei_cl_driver(mei_pxp_driver);

	MODULE_AUTHOR("Intel Corporation");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("MEI PXP");