drivers/rpmsg/rpmsg_ns.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) STMicroelectronics 2020 - All Rights Reserved
   4  */
   5 #include <linux/device.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/rpmsg.h>
   9 #include <linux/rpmsg/ns.h>
  10 #include <linux/slab.h>
  11
  12 #include "rpmsg_internal.h"
  13
  14 /**
  15  * rpmsg_ns_register_device() - register name service device based on rpdev
  16  * @rpdev: prepared rpdev to be used for creating endpoints
  17  *
  18  * This function wraps rpmsg_register_device() preparing the rpdev for use as
  19  * basis for the rpmsg name service device.
  20  */
  21 int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
  22 {
  23         rpdev->src = RPMSG_NS_ADDR;
  24         rpdev->dst = RPMSG_NS_ADDR;
  25
  26         return rpmsg_register_device_override(rpdev, "rpmsg_ns");
  27 }
  28 EXPORT_SYMBOL(rpmsg_ns_register_device);
  29
  30 /* invoked when a name service announcement arrives */
  31 static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
  32                        void *priv, u32 src)
  33 {
  34         struct rpmsg_ns_msg *msg = data;
  35         struct rpmsg_device *newch;
  36         struct rpmsg_channel_info chinfo;
  37         struct device *dev = rpdev->dev.parent;
  38         int ret;
  39
  40 #if defined(CONFIG_DYNAMIC_DEBUG)
  41         dynamic_hex_dump("NS announcement: ", DUMP_PREFIX_NONE, 16, 1,
  42                          data, len, true);
  43 #endif
  44
  45         if (len != sizeof(*msg)) {
  46                 dev_err(dev, "malformed ns msg (%d)\n", len);
  47                 return -EINVAL;
  48         }
  49
  50         /* don't trust the remote processor for null terminating the name */
  51         msg->name[RPMSG_NAME_SIZE - 1] = '\0';
  52
  53         strscpy_pad(chinfo.name, msg->name, sizeof(chinfo.name));
  54         chinfo.src = RPMSG_ADDR_ANY;
  55         chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr);
  56
  57         dev_info(dev, "%sing channel %s addr 0x%x\n",
  58                  rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY ?
  59                  "destroy" : "creat", msg->name, chinfo.dst);
  60
  61         if (rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY) {
  62                 ret = rpmsg_release_channel(rpdev, &chinfo);
  63                 if (ret)
  64                         dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
  65         } else {
  66                 newch = rpmsg_create_channel(rpdev, &chinfo);
  67                 if (!newch)
  68                         dev_err(dev, "rpmsg_create_channel failed\n");
  69         }
  70
  71         return 0;
  72 }
  73
  74 static int rpmsg_ns_probe(struct rpmsg_device *rpdev)
  75 {
  76         struct rpmsg_endpoint *ns_ept;
  77         struct rpmsg_channel_info ns_chinfo = {
  78                 .src = RPMSG_NS_ADDR,
  79                 .dst = RPMSG_NS_ADDR,
  80                 .name = "name_service",
  81         };
  82
  83         /*
  84          * Create the NS announcement service endpoint associated to the RPMsg
  85          * device. The endpoint will be automatically destroyed when the RPMsg
  86          * device will be deleted.
  87          */
  88         ns_ept = rpmsg_create_ept(rpdev, rpmsg_ns_cb, NULL, ns_chinfo);
  89         if (!ns_ept) {
  90                 dev_err(&rpdev->dev, "failed to create the ns ept\n");
  91                 return -ENOMEM;
  92         }
  93         rpdev->ept = ns_ept;
  94
  95         return 0;
  96 }
  97
  98 static struct rpmsg_driver rpmsg_ns_driver = {
  99         .drv.name = KBUILD_MODNAME,
 100         .probe = rpmsg_ns_probe,
 101 };
 102
 103 static int rpmsg_ns_init(void)
 104 {
 105         int ret;
 106
 107         ret = register_rpmsg_driver(&rpmsg_ns_driver);
 108         if (ret < 0)
 109                 pr_err("%s: Failed to register rpmsg driver\n", __func__);
 110
 111         return ret;
 112 }
 113 postcore_initcall(rpmsg_ns_init);
 114
 115 static void rpmsg_ns_exit(void)
 116 {
 117         unregister_rpmsg_driver(&rpmsg_ns_driver);
 118 }
 119 module_exit(rpmsg_ns_exit);
 120
 121 MODULE_DESCRIPTION("Name service announcement rpmsg driver");
 122 MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
 123 MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
 124 MODULE_LICENSE("GPL v2");