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  */
22 struct 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  */
36 struct 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 
48 struct 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 */
59 static 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  */
65 void qcom_glink_ssr_notify(const char *ssr_name)
66 {
67 	blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr_name);
68 }
69 EXPORT_SYMBOL_GPL(qcom_glink_ssr_notify);
70 
71 static 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 
98 static 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 	strlcpy(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 
127 static 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 
146 static 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 
153 static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
154 	{ "glink_ssr" },
155 	{}
156 };
157 
158 static 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 };
167 module_rpmsg_driver(qcom_glink_ssr_driver);
168