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/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  */
  21 struct 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  */
  35 struct 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
  47 struct 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 */
  58 static 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  */
  64 void qcom_glink_ssr_notify(const char *ssr_name)
  65 {
  66         blocking_notifier_call_chain(&ssr_notifiers, 0, (void *)ssr_name);
  67 }
  68 EXPORT_SYMBOL_GPL(qcom_glink_ssr_notify);
  69
  70 static 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
  97 static 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
 126 static 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
 145 static 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
 152 static const struct rpmsg_device_id qcom_glink_ssr_match[] = {
 153         { "glink_ssr" },
 154         {}
 155 };
 156
 157 static 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 };
 166 module_rpmsg_driver(qcom_glink_ssr_driver);