1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright © 2020 - 2021 Intel Corporation
4 */
5
6/**
7 * DOC: MEI_PXP Client Driver
8 *
9 * The mei_pxp driver acts as a translation layer between PXP
10 * protocol  implementer (I915) and ME FW by translating PXP
11 * negotiation messages to ME FW command payloads and vice versa.
12 */
13
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/mei.h>
17#include <linux/mei_cl_bus.h>
18#include <linux/component.h>
19#include <drm/drm_connector.h>
20#include <drm/i915_component.h>
21#include <drm/i915_pxp_tee_interface.h>
22
23#include "mei_pxp.h"
24
25/**
26 * mei_pxp_send_message() - Sends a PXP message to ME FW.
27 * @dev: device corresponding to the mei_cl_device
28 * @message: a message buffer to send
29 * @size: size of the message
30 * Return: 0 on Success, <0 on Failure
31 */
32static int
33mei_pxp_send_message(struct device *dev, const void *message, size_t size)
34{
35	struct mei_cl_device *cldev;
36	ssize_t byte;
37
38	if (!dev || !message)
39		return -EINVAL;
40
41	cldev = to_mei_cl_device(dev);
42
43	byte = mei_cldev_send(cldev, message, size);
44	if (byte < 0) {
45		dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte);
46		return byte;
47	}
48
49	return 0;
50}
51
52/**
53 * mei_pxp_receive_message() - Receives a PXP message from ME FW.
54 * @dev: device corresponding to the mei_cl_device
55 * @buffer: a message buffer to contain the received message
56 * @size: size of the buffer
57 * Return: bytes sent on Success, <0 on Failure
58 */
59static int
60mei_pxp_receive_message(struct device *dev, void *buffer, size_t size)
61{
62	struct mei_cl_device *cldev;
63	ssize_t byte;
64
65	if (!dev || !buffer)
66		return -EINVAL;
67
68	cldev = to_mei_cl_device(dev);
69
70	byte = mei_cldev_recv(cldev, buffer, size);
71	if (byte < 0) {
72		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
73		return byte;
74	}
75
76	return byte;
77}
78
79/**
80 * mei_pxp_gsc_command() - sends a gsc command, by sending
81 * a sgl mei message to gsc and receiving reply from gsc
82 *
83 * @dev: device corresponding to the mei_cl_device
84 * @client_id: client id to send the command to
85 * @fence_id: fence id to send the command to
86 * @sg_in: scatter gather list containing addresses for rx message buffer
87 * @total_in_len: total length of data in 'in' sg, can be less than the sum of buffers sizes
88 * @sg_out: scatter gather list containing addresses for tx message buffer
89 *
90 * Return: bytes sent on Success, <0 on Failure
91 */
92static ssize_t mei_pxp_gsc_command(struct device *dev, u8 client_id, u32 fence_id,
93				   struct scatterlist *sg_in, size_t total_in_len,
94				   struct scatterlist *sg_out)
95{
96	struct mei_cl_device *cldev;
97
98	cldev = to_mei_cl_device(dev);
99
100	return mei_cldev_send_gsc_command(cldev, client_id, fence_id, sg_in, total_in_len, sg_out);
101}
102
103static const struct i915_pxp_component_ops mei_pxp_ops = {
104	.owner = THIS_MODULE,
105	.send = mei_pxp_send_message,
106	.recv = mei_pxp_receive_message,
107	.gsc_command = mei_pxp_gsc_command,
108};
109
110static int mei_component_master_bind(struct device *dev)
111{
112	struct mei_cl_device *cldev = to_mei_cl_device(dev);
113	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
114	int ret;
115
116	comp_master->ops = &mei_pxp_ops;
117	comp_master->tee_dev = dev;
118	ret = component_bind_all(dev, comp_master);
119	if (ret < 0)
120		return ret;
121
122	return 0;
123}
124
125static void mei_component_master_unbind(struct device *dev)
126{
127	struct mei_cl_device *cldev = to_mei_cl_device(dev);
128	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
129
130	component_unbind_all(dev, comp_master);
131}
132
133static const struct component_master_ops mei_component_master_ops = {
134	.bind = mei_component_master_bind,
135	.unbind = mei_component_master_unbind,
136};
137
138/**
139 * mei_pxp_component_match - compare function for matching mei pxp.
140 *
141 *    The function checks if the driver is i915, the subcomponent is PXP
142 *    and the grand parent of pxp and the parent of i915 are the same
143 *    PCH device.
144 *
145 * @dev: master device
146 * @subcomponent: subcomponent to match (I915_COMPONENT_PXP)
147 * @data: compare data (mei pxp device)
148 *
149 * Return:
150 * * 1 - if components match
151 * * 0 - otherwise
152 */
153static int mei_pxp_component_match(struct device *dev, int subcomponent,
154				   void *data)
155{
156	struct device *base = data;
157
158	if (!dev)
159		return 0;
160
161	if (!dev->driver || strcmp(dev->driver->name, "i915") ||
162	    subcomponent != I915_COMPONENT_PXP)
163		return 0;
164
165	base = base->parent;
166	if (!base) /* mei device */
167		return 0;
168
169	base = base->parent; /* pci device */
170	/* for dgfx */
171	if (base && dev == base)
172		return 1;
173
174	/* for pch */
175	dev = dev->parent;
176	return (base && dev && dev == base);
177}
178
179static int mei_pxp_probe(struct mei_cl_device *cldev,
180			 const struct mei_cl_device_id *id)
181{
182	struct i915_pxp_component *comp_master;
183	struct component_match *master_match;
184	int ret;
185
186	ret = mei_cldev_enable(cldev);
187	if (ret < 0) {
188		dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret);
189		goto enable_err_exit;
190	}
191
192	comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL);
193	if (!comp_master) {
194		ret = -ENOMEM;
195		goto err_exit;
196	}
197
198	master_match = NULL;
199	component_match_add_typed(&cldev->dev, &master_match,
200				  mei_pxp_component_match, &cldev->dev);
201	if (IS_ERR_OR_NULL(master_match)) {
202		ret = -ENOMEM;
203		goto err_exit;
204	}
205
206	mei_cldev_set_drvdata(cldev, comp_master);
207	ret = component_master_add_with_match(&cldev->dev,
208					      &mei_component_master_ops,
209					      master_match);
210	if (ret < 0) {
211		dev_err(&cldev->dev, "Master comp add failed %d\n", ret);
212		goto err_exit;
213	}
214
215	return 0;
216
217err_exit:
218	mei_cldev_set_drvdata(cldev, NULL);
219	kfree(comp_master);
220	mei_cldev_disable(cldev);
221enable_err_exit:
222	return ret;
223}
224
225static void mei_pxp_remove(struct mei_cl_device *cldev)
226{
227	struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev);
228	int ret;
229
230	component_master_del(&cldev->dev, &mei_component_master_ops);
231	kfree(comp_master);
232	mei_cldev_set_drvdata(cldev, NULL);
233
234	ret = mei_cldev_disable(cldev);
235	if (ret)
236		dev_warn(&cldev->dev, "mei_cldev_disable() failed\n");
237}
238
239/* fbf6fcf1-96cf-4e2e-a6a6-1bab8cbe36b1 : PAVP GUID*/
240#define MEI_GUID_PXP UUID_LE(0xfbf6fcf1, 0x96cf, 0x4e2e, 0xA6, \
241			     0xa6, 0x1b, 0xab, 0x8c, 0xbe, 0x36, 0xb1)
242
243static struct mei_cl_device_id mei_pxp_tbl[] = {
244	{ .uuid = MEI_GUID_PXP, .version = MEI_CL_VERSION_ANY },
245	{ }
246};
247MODULE_DEVICE_TABLE(mei, mei_pxp_tbl);
248
249static struct mei_cl_driver mei_pxp_driver = {
250	.id_table = mei_pxp_tbl,
251	.name = KBUILD_MODNAME,
252	.probe = mei_pxp_probe,
253	.remove	= mei_pxp_remove,
254};
255
256module_mei_cl_driver(mei_pxp_driver);
257
258MODULE_AUTHOR("Intel Corporation");
259MODULE_LICENSE("GPL");
260MODULE_DESCRIPTION("MEI PXP");
261