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/rpmsg/qcom_glink.h>
12#include <linux/remoteproc/qcom_rproc.h>
13
14/**
15 * struct do_cleanup_msg - The data structure for an SSR do_cleanup message
16 * @version:	The G-Link SSR protocol version
17 * @command:	The G-Link SSR command - do_cleanup
18 * @seq_num:	Sequence number
19 * @name_len:	Length of the name of the subsystem being restarted
20 * @name:	G-Link edge name of the subsystem being restarted
21 */
22struct do_cleanup_msg {
23	__le32 version;
24	__le32 command;
25	__le32 seq_num;
26	__le32 name_len;
27	char name[32];
28};
29
30/**
31 * struct cleanup_done_msg - The data structure for an SSR cleanup_done message
32 * @version:	The G-Link SSR protocol version
33 * @response:	The G-Link SSR response to a do_cleanup command, cleanup_done
34 * @seq_num:	Sequence number
35 */
36struct cleanup_done_msg {
37	__le32 version;
38	__le32 response;
39	__le32 seq_num;
40};
41
42/*
43 * G-Link SSR protocol commands
44 */
45#define GLINK_SSR_DO_CLEANUP	0
46#define GLINK_SSR_CLEANUP_DONE	1
47
48struct glink_ssr {
49	struct device *dev;
50	struct rpmsg_endpoint *ept;
51
52	struct notifier_block nb;
53
54	u32 seq_num;
55	struct completion completion;
56};
57
58/* Notifier list for all registered glink_ssr instances */
59static BLOCKING_NOTIFIER_HEAD(ssr_notifiers);
60
61/**
62 * qcom_glink_ssr_notify() - notify GLINK SSR about stopped remoteproc
63 * @ssr_name:	name of the remoteproc that has been stopped
64 */
65void qcom_glink_ssr_notify(const char *ssr_name)
66{
67	blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr_name);
68}
69EXPORT_SYMBOL_GPL(qcom_glink_ssr_notify);
70
71static int qcom_glink_ssr_callback(struct rpmsg_device *rpdev,
72				   void *data, int len, void *priv, u32 addr)
73{
74	struct cleanup_done_msg *msg = data;
75	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
76
77	if (len < sizeof(*msg)) {
78		dev_err(ssr->dev, "message too short\n");
79		return -EINVAL;
80	}
81
82	if (le32_to_cpu(msg->version) != 0)
83		return -EINVAL;
84
85	if (le32_to_cpu(msg->response) != GLINK_SSR_CLEANUP_DONE)
86		return 0;
87
88	if (le32_to_cpu(msg->seq_num) != ssr->seq_num) {
89		dev_err(ssr->dev, "invalid sequence number of response\n");
90		return -EINVAL;
91	}
92
93	complete(&ssr->completion);
94
95	return 0;
96}
97
98static int qcom_glink_ssr_notifier_call(struct notifier_block *nb,
99					unsigned long event,
100					void *data)
101{
102	struct glink_ssr *ssr = container_of(nb, struct glink_ssr, nb);
103	struct do_cleanup_msg msg;
104	char *ssr_name = data;
105	int ret;
106
107	ssr->seq_num++;
108	reinit_completion(&ssr->completion);
109
110	memset(&msg, 0, sizeof(msg));
111	msg.command = cpu_to_le32(GLINK_SSR_DO_CLEANUP);
112	msg.seq_num = cpu_to_le32(ssr->seq_num);
113	msg.name_len = cpu_to_le32(strlen(ssr_name));
114	strscpy(msg.name, ssr_name, sizeof(msg.name));
115
116	ret = rpmsg_send(ssr->ept, &msg, sizeof(msg));
117	if (ret < 0)
118		dev_err(ssr->dev, "failed to send cleanup message\n");
119
120	ret = wait_for_completion_timeout(&ssr->completion, HZ);
121	if (!ret)
122		dev_err(ssr->dev, "timeout waiting for cleanup done message\n");
123
124	return NOTIFY_DONE;
125}
126
127static int qcom_glink_ssr_probe(struct rpmsg_device *rpdev)
128{
129	struct glink_ssr *ssr;
130
131	ssr = devm_kzalloc(&rpdev->dev, sizeof(*ssr), GFP_KERNEL);
132	if (!ssr)
133		return -ENOMEM;
134
135	init_completion(&ssr->completion);
136
137	ssr->dev = &rpdev->dev;
138	ssr->ept = rpdev->ept;
139	ssr->nb.notifier_call = qcom_glink_ssr_notifier_call;
140
141	dev_set_drvdata(&rpdev->dev, ssr);
142
143	return blocking_notifier_chain_register(&ssr_notifiers, &ssr->nb);
144}
145
146static void qcom_glink_ssr_remove(struct rpmsg_device *rpdev)
147{
148	struct glink_ssr *ssr = dev_get_drvdata(&rpdev->dev);
149
150	blocking_notifier_chain_unregister(&ssr_notifiers, &ssr->nb);
151}
152
153static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
154	{ "glink_ssr" },
155	{}
156};
157
158static struct rpmsg_driver qcom_glink_ssr_driver = {
159	.probe = qcom_glink_ssr_probe,
160	.remove = qcom_glink_ssr_remove,
161	.callback = qcom_glink_ssr_callback,
162	.id_table = qcom_glink_ssr_match,
163	.drv = {
164		.name = "qcom_glink_ssr",
165	},
166};
167module_rpmsg_driver(qcom_glink_ssr_driver);
168