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 */
 21int 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}
 28EXPORT_SYMBOL(rpmsg_ns_register_device);
 29
 30/* invoked when a name service announcement arrives */
 31static 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
 74static 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
 98static struct rpmsg_driver rpmsg_ns_driver = {
 99	.drv.name = KBUILD_MODNAME,
100	.probe = rpmsg_ns_probe,
101};
102
103static 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}
113postcore_initcall(rpmsg_ns_init);
114
115static void rpmsg_ns_exit(void)
116{
117	unregister_rpmsg_driver(&rpmsg_ns_driver);
118}
119module_exit(rpmsg_ns_exit);
120
121MODULE_DESCRIPTION("Name service announcement rpmsg driver");
122MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
123MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
124MODULE_LICENSE("GPL v2");