1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
4 * Copyright (c) 2017, Linaro Ltd.
5 */
6
7#include <linux/completion.h>
8#include <linux/module.h>
9#include <linux/notifier.h>
10#include <linux/rpmsg.h>
11#include <linux/remoteproc/qcom_rproc.h>
12
13/**
14 * struct do_cleanup_msg - The data structure for an SSR do_cleanup message
15 * version:     The G-Link SSR protocol version
16 * command:     The G-Link SSR command - do_cleanup
17 * seq_num:     Sequence number
18 * name_len:    Length of the name of the subsystem being restarted
19 * name:        G-Link edge name of the subsystem being restarted
20 */
21struct do_cleanup_msg {
22	__le32 version;
23	__le32 command;
24	__le32 seq_num;
25	__le32 name_len;
26	char name[32];
27};
28
29/**
30 * struct cleanup_done_msg - The data structure for an SSR cleanup_done message
31 * version:     The G-Link SSR protocol version
32 * response:    The G-Link SSR response to a do_cleanup command, cleanup_done
33 * seq_num:     Sequence number
34 */
35struct cleanup_done_msg {
36	__le32 version;
37	__le32 response;
38	__le32 seq_num;
39};
40
41/**
42 * G-Link SSR protocol commands
43 */
44#define GLINK_SSR_DO_CLEANUP	0
45#define GLINK_SSR_CLEANUP_DONE	1
46
47struct glink_ssr {
48	struct device *dev;
49	struct rpmsg_endpoint *ept;
50
51	struct notifier_block nb;
52
53	u32 seq_num;
54	struct completion completion;
55};
56
57/* Notifier list for all registered glink_ssr instances */
58static BLOCKING_NOTIFIER_HEAD(ssr_notifiers);
59
60/**
61 * qcom_glink_ssr_notify() - notify GLINK SSR about stopped remoteproc
62 * @ssr_name:	name of the remoteproc that has been stopped
63 */
64void qcom_glink_ssr_notify(const char *ssr_name)
65{
66	blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr_name);
67}
68EXPORT_SYMBOL_GPL(qcom_glink_ssr_notify);
69
70static int qcom_glink_ssr_callback(struct rpmsg_device *rpdev,
71				   void *data, int len, void *priv, u32 addr)
72{
73	struct cleanup_done_msg *msg = data;
74	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
75
76	if (len < sizeof(*msg)) {
77		dev_err(ssr->dev, "message too short\n");
78		return -EINVAL;
79	}
80
81	if (le32_to_cpu(msg->version) != 0)
82		return -EINVAL;
83
84	if (le32_to_cpu(msg->response) != GLINK_SSR_CLEANUP_DONE)
85		return 0;
86
87	if (le32_to_cpu(msg->seq_num) != ssr->seq_num) {
88		dev_err(ssr->dev, "invalid sequence number of response\n");
89		return -EINVAL;
90	}
91
92	complete(&ssr->completion);
93
94	return 0;
95}
96
97static int qcom_glink_ssr_notifier_call(struct notifier_block *nb,
98					unsigned long event,
99					void *data)
100{
101	struct glink_ssr *ssr = container_of(nb, struct glink_ssr, nb);
102	struct do_cleanup_msg msg;
103	char *ssr_name = data;
104	int ret;
105
106	ssr->seq_num++;
107	reinit_completion(&ssr->completion);
108
109	memset(&msg, 0, sizeof(msg));
110	msg.command = cpu_to_le32(GLINK_SSR_DO_CLEANUP);
111	msg.seq_num = cpu_to_le32(ssr->seq_num);
112	msg.name_len = cpu_to_le32(strlen(ssr_name));
113	strlcpy(msg.name, ssr_name, sizeof(msg.name));
114
115	ret = rpmsg_send(ssr->ept, &msg, sizeof(msg));
116	if (ret < 0)
117		dev_err(ssr->dev, "failed to send cleanup message\n");
118
119	ret = wait_for_completion_timeout(&ssr->completion, HZ);
120	if (!ret)
121		dev_err(ssr->dev, "timeout waiting for cleanup done message\n");
122
123	return NOTIFY_DONE;
124}
125
126static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev)
127{
128	struct glink_ssr *ssr;
129
130	ssr = devm_kzalloc(&rpdev->dev, sizeof(*ssr), GFP_KERNEL);
131	if (!ssr)
132		return -ENOMEM;
133
134	init_completion(&ssr->completion);
135
136	ssr->dev = &rpdev->dev;
137	ssr->ept = rpdev->ept;
138	ssr->nb.notifier_call = qcom_glink_ssr_notifier_call;
139
140	dev_set_drvdata(&rpdev->dev, ssr);
141
142	return blocking_notifier_chain_register(&ssr_notifiers, &ssr->nb);
143}
144
145static void qcom_glink_ssr_remove(struct rpmsg_device *rpdev)
146{
147	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
148
149	blocking_notifier_chain_unregister(&ssr_notifiers, &ssr->nb);
150}
151
152static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
153	{ "glink_ssr" },
154	{}
155};
156
157static struct rpmsg_driver qcom_glink_ssr_driver = {
158	.probe = qcom_glink_ssr_probe,
159	.remove = qcom_glink_ssr_remove,
160	.callback = qcom_glink_ssr_callback,
161	.id_table = qcom_glink_ssr_match,
162	.drv = {
163		.name = "qcom_glink_ssr",
164	},
165};
166module_rpmsg_driver(qcom_glink_ssr_driver);
167