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         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
 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);