// 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/pci.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;
struct pci_dev *pdev;
if (!dev)
return 0;
if (!dev_is_pci(dev))
return 0;
pdev = to_pci_dev(dev);
if (pdev->vendor != PCI_VENDOR_ID_INTEL)
return 0;
if (pdev->class != (PCI_CLASS_DISPLAY_VGA << 8) &&
pdev->class != (PCI_CLASS_DISPLAY_OTHER << 8))
return 0;
if (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");
