1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015, Sony Mobile Communications AB.
4 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
5 */
6
7#include <linux/module.h>
8#include <linux/platform_device.h>
9#include <linux/of_platform.h>
10#include <linux/io.h>
11#include <linux/interrupt.h>
12#include <linux/slab.h>
13
14#include <linux/rpmsg.h>
15#include <linux/soc/qcom/smd-rpm.h>
16
17#define RPM_REQUEST_TIMEOUT     (5 * HZ)
18
19/**
20 * struct qcom_smd_rpm - state of the rpm device driver
21 * @rpm_channel:	reference to the smd channel
22 * @dev:		rpm device
23 * @ack:		completion for acks
24 * @lock:		mutual exclusion around the send/complete pair
25 * @ack_status:		result of the rpm request
26 */
27struct qcom_smd_rpm {
28	struct rpmsg_endpoint *rpm_channel;
29	struct device *dev;
30
31	struct completion ack;
32	struct mutex lock;
33	int ack_status;
34};
35
36/**
37 * struct qcom_rpm_header - header for all rpm requests and responses
38 * @service_type:	identifier of the service
39 * @length:		length of the payload
40 */
41struct qcom_rpm_header {
42	__le32 service_type;
43	__le32 length;
44};
45
46/**
47 * struct qcom_rpm_request - request message to the rpm
48 * @msg_id:	identifier of the outgoing message
49 * @flags:	active/sleep state flags
50 * @type:	resource type
51 * @id:		resource id
52 * @data_len:	length of the payload following this header
53 */
54struct qcom_rpm_request {
55	__le32 msg_id;
56	__le32 flags;
57	__le32 type;
58	__le32 id;
59	__le32 data_len;
60};
61
62/**
63 * struct qcom_rpm_message - response message from the rpm
64 * @msg_type:	indicator of the type of message
65 * @length:	the size of this message, including the message header
66 * @msg_id:	message id
67 * @message:	textual message from the rpm
68 *
69 * Multiple of these messages can be stacked in an rpm message.
70 */
71struct qcom_rpm_message {
72	__le32 msg_type;
73	__le32 length;
74	union {
75		__le32 msg_id;
76		DECLARE_FLEX_ARRAY(u8, message);
77	};
78};
79
80#define RPM_SERVICE_TYPE_REQUEST	0x00716572 /* "req\0" */
81
82#define RPM_MSG_TYPE_ERR		0x00727265 /* "err\0" */
83#define RPM_MSG_TYPE_MSG_ID		0x2367736d /* "msg#" */
84
85/**
86 * qcom_rpm_smd_write - write @buf to @type:@id
87 * @rpm:	rpm handle
88 * @state:	active/sleep state flags
89 * @type:	resource type
90 * @id:		resource identifier
91 * @buf:	the data to be written
92 * @count:	number of bytes in @buf
93 */
94int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
95		       int state,
96		       u32 type, u32 id,
97		       void *buf,
98		       size_t count)
99{
100	static unsigned msg_id = 1;
101	int left;
102	int ret;
103	struct {
104		struct qcom_rpm_header hdr;
105		struct qcom_rpm_request req;
106		u8 payload[];
107	} *pkt;
108	size_t size = sizeof(*pkt) + count;
109
110	/* SMD packets to the RPM may not exceed 256 bytes */
111	if (WARN_ON(size >= 256))
112		return -EINVAL;
113
114	pkt = kmalloc(size, GFP_ATOMIC);
115	if (!pkt)
116		return -ENOMEM;
117
118	mutex_lock(&rpm->lock);
119
120	pkt->hdr.service_type = cpu_to_le32(RPM_SERVICE_TYPE_REQUEST);
121	pkt->hdr.length = cpu_to_le32(sizeof(struct qcom_rpm_request) + count);
122
123	pkt->req.msg_id = cpu_to_le32(msg_id++);
124	pkt->req.flags = cpu_to_le32(state);
125	pkt->req.type = cpu_to_le32(type);
126	pkt->req.id = cpu_to_le32(id);
127	pkt->req.data_len = cpu_to_le32(count);
128	memcpy(pkt->payload, buf, count);
129
130	ret = rpmsg_send(rpm->rpm_channel, pkt, size);
131	if (ret)
132		goto out;
133
134	left = wait_for_completion_timeout(&rpm->ack, RPM_REQUEST_TIMEOUT);
135	if (!left)
136		ret = -ETIMEDOUT;
137	else
138		ret = rpm->ack_status;
139
140out:
141	kfree(pkt);
142	mutex_unlock(&rpm->lock);
143	return ret;
144}
145EXPORT_SYMBOL(qcom_rpm_smd_write);
146
147static int qcom_smd_rpm_callback(struct rpmsg_device *rpdev,
148				 void *data,
149				 int count,
150				 void *priv,
151				 u32 addr)
152{
153	const struct qcom_rpm_header *hdr = data;
154	size_t hdr_length = le32_to_cpu(hdr->length);
155	const struct qcom_rpm_message *msg;
156	struct qcom_smd_rpm *rpm = dev_get_drvdata(&rpdev->dev);
157	const u8 *buf = data + sizeof(struct qcom_rpm_header);
158	const u8 *end = buf + hdr_length;
159	char msgbuf[32];
160	int status = 0;
161	u32 len, msg_length;
162
163	if (le32_to_cpu(hdr->service_type) != RPM_SERVICE_TYPE_REQUEST ||
164	    hdr_length < sizeof(struct qcom_rpm_message)) {
165		dev_err(rpm->dev, "invalid request\n");
166		return 0;
167	}
168
169	while (buf < end) {
170		msg = (struct qcom_rpm_message *)buf;
171		msg_length = le32_to_cpu(msg->length);
172		switch (le32_to_cpu(msg->msg_type)) {
173		case RPM_MSG_TYPE_MSG_ID:
174			break;
175		case RPM_MSG_TYPE_ERR:
176			len = min_t(u32, ALIGN(msg_length, 4), sizeof(msgbuf));
177			memcpy_fromio(msgbuf, msg->message, len);
178			msgbuf[len - 1] = 0;
179
180			if (!strcmp(msgbuf, "resource does not exist"))
181				status = -ENXIO;
182			else
183				status = -EINVAL;
184			break;
185		}
186
187		buf = PTR_ALIGN(buf + 2 * sizeof(u32) + msg_length, 4);
188	}
189
190	rpm->ack_status = status;
191	complete(&rpm->ack);
192	return 0;
193}
194
195static int qcom_smd_rpm_probe(struct rpmsg_device *rpdev)
196{
197	struct qcom_smd_rpm *rpm;
198
199	if (!rpdev->dev.of_node)
200		return -EINVAL;
201
202	rpm = devm_kzalloc(&rpdev->dev, sizeof(*rpm), GFP_KERNEL);
203	if (!rpm)
204		return -ENOMEM;
205
206	mutex_init(&rpm->lock);
207	init_completion(&rpm->ack);
208
209	rpm->dev = &rpdev->dev;
210	rpm->rpm_channel = rpdev->ept;
211	dev_set_drvdata(&rpdev->dev, rpm);
212
213	return of_platform_populate(rpdev->dev.of_node, NULL, NULL, &rpdev->dev);
214}
215
216static void qcom_smd_rpm_remove(struct rpmsg_device *rpdev)
217{
218	of_platform_depopulate(&rpdev->dev);
219}
220
221static const struct rpmsg_device_id qcom_smd_rpm_id_table[] = {
222	{ .name = "rpm_requests", },
223	{ /* sentinel */ }
224};
225MODULE_DEVICE_TABLE(rpmsg, qcom_smd_rpm_id_table);
226
227static struct rpmsg_driver qcom_smd_rpm_driver = {
228	.probe = qcom_smd_rpm_probe,
229	.remove = qcom_smd_rpm_remove,
230	.callback = qcom_smd_rpm_callback,
231	.id_table = qcom_smd_rpm_id_table,
232	.drv.name = "qcom_smd_rpm",
233};
234
235static int __init qcom_smd_rpm_init(void)
236{
237	return register_rpmsg_driver(&qcom_smd_rpm_driver);
238}
239arch_initcall(qcom_smd_rpm_init);
240
241static void __exit qcom_smd_rpm_exit(void)
242{
243	unregister_rpmsg_driver(&qcom_smd_rpm_driver);
244}
245module_exit(qcom_smd_rpm_exit);
246
247MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
248MODULE_DESCRIPTION("Qualcomm SMD backed RPM driver");
249MODULE_LICENSE("GPL v2");
250