GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / rpmsg / qcom_glink_ssr.c
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);