1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2022, STMicroelectronics
4 * Copyright (c) 2016, Linaro Ltd.
5 * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
6 * Copyright (c) 2012, PetaLogix
7 * Copyright (c) 2011, Texas Instruments, Inc.
8 * Copyright (c) 2011, Google, Inc.
9 *
10 * Based on rpmsg performance statistics driver by Michal Simek, which in turn
11 * was based on TI & Google OMX rpmsg driver.
12 */
13
14#define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
15
16#include <linux/cdev.h>
17#include <linux/device.h>
18#include <linux/fs.h>
19#include <linux/idr.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/rpmsg.h>
23#include <linux/skbuff.h>
24#include <linux/slab.h>
25#include <linux/uaccess.h>
26#include <uapi/linux/rpmsg.h>
27
28#include "rpmsg_char.h"
29#include "rpmsg_internal.h"
30
31#define RPMSG_DEV_MAX	(MINORMASK + 1)
32
33static dev_t rpmsg_major;
34
35static DEFINE_IDA(rpmsg_ctrl_ida);
36static DEFINE_IDA(rpmsg_minor_ida);
37
38#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
39#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
40
41/**
42 * struct rpmsg_ctrldev - control device for instantiating endpoint devices
43 * @rpdev:	underlaying rpmsg device
44 * @cdev:	cdev for the ctrl device
45 * @dev:	device for the ctrl device
46 * @ctrl_lock:	serialize the ioctrls.
47 */
48struct rpmsg_ctrldev {
49	struct rpmsg_device *rpdev;
50	struct cdev cdev;
51	struct device dev;
52	struct mutex ctrl_lock;
53};
54
55static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
56{
57	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
58
59	get_device(&ctrldev->dev);
60	filp->private_data = ctrldev;
61
62	return 0;
63}
64
65static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
66{
67	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
68
69	put_device(&ctrldev->dev);
70
71	return 0;
72}
73
74static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
75				unsigned long arg)
76{
77	struct rpmsg_ctrldev *ctrldev = fp->private_data;
78	void __user *argp = (void __user *)arg;
79	struct rpmsg_endpoint_info eptinfo;
80	struct rpmsg_channel_info chinfo;
81	struct rpmsg_device *rpdev;
82	int ret = 0;
83
84	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
85		return -EFAULT;
86
87	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
88	chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
89	chinfo.src = eptinfo.src;
90	chinfo.dst = eptinfo.dst;
91
92	mutex_lock(&ctrldev->ctrl_lock);
93	switch (cmd) {
94	case RPMSG_CREATE_EPT_IOCTL:
95		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
96		break;
97
98	case RPMSG_CREATE_DEV_IOCTL:
99		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
100		if (!rpdev) {
101			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
102			ret = -ENXIO;
103		}
104		break;
105
106	case RPMSG_RELEASE_DEV_IOCTL:
107		ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo);
108		if (ret)
109			dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n",
110				chinfo.name, ret);
111		break;
112
113	default:
114		ret = -EINVAL;
115	}
116	mutex_unlock(&ctrldev->ctrl_lock);
117
118	return ret;
119};
120
121static const struct file_operations rpmsg_ctrldev_fops = {
122	.owner = THIS_MODULE,
123	.open = rpmsg_ctrldev_open,
124	.release = rpmsg_ctrldev_release,
125	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
126	.compat_ioctl = compat_ptr_ioctl,
127};
128
129static void rpmsg_ctrldev_release_device(struct device *dev)
130{
131	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
132
133	ida_free(&rpmsg_ctrl_ida, dev->id);
134	ida_free(&rpmsg_minor_ida, MINOR(dev->devt));
135	kfree(ctrldev);
136}
137
138static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
139{
140	struct rpmsg_ctrldev *ctrldev;
141	struct device *dev;
142	int ret;
143
144	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
145	if (!ctrldev)
146		return -ENOMEM;
147
148	ctrldev->rpdev = rpdev;
149
150	dev = &ctrldev->dev;
151	device_initialize(dev);
152	dev->parent = &rpdev->dev;
153	dev->class = rpmsg_class;
154
155	mutex_init(&ctrldev->ctrl_lock);
156	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
157	ctrldev->cdev.owner = THIS_MODULE;
158
159	ret = ida_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL);
160	if (ret < 0)
161		goto free_ctrldev;
162	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
163
164	ret = ida_alloc(&rpmsg_ctrl_ida, GFP_KERNEL);
165	if (ret < 0)
166		goto free_minor_ida;
167	dev->id = ret;
168	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
169
170	ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev);
171	if (ret)
172		goto free_ctrl_ida;
173
174	/* We can now rely on the release function for cleanup */
175	dev->release = rpmsg_ctrldev_release_device;
176
177	dev_set_drvdata(&rpdev->dev, ctrldev);
178
179	return ret;
180
181free_ctrl_ida:
182	ida_free(&rpmsg_ctrl_ida, dev->id);
183free_minor_ida:
184	ida_free(&rpmsg_minor_ida, MINOR(dev->devt));
185free_ctrldev:
186	put_device(dev);
187	kfree(ctrldev);
188
189	return ret;
190}
191
192static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
193{
194	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
195	int ret;
196
197	mutex_lock(&ctrldev->ctrl_lock);
198	/* Destroy all endpoints */
199	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
200	if (ret)
201		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
202	mutex_unlock(&ctrldev->ctrl_lock);
203
204	cdev_device_del(&ctrldev->cdev, &ctrldev->dev);
205	put_device(&ctrldev->dev);
206}
207
208static struct rpmsg_driver rpmsg_ctrldev_driver = {
209	.probe = rpmsg_ctrldev_probe,
210	.remove = rpmsg_ctrldev_remove,
211	.drv = {
212		.name = "rpmsg_ctrl",
213	},
214};
215
216static int rpmsg_ctrldev_init(void)
217{
218	int ret;
219
220	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_ctrl");
221	if (ret < 0) {
222		pr_err("failed to allocate char dev region\n");
223		return ret;
224	}
225
226	ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
227	if (ret < 0) {
228		pr_err("failed to register rpmsg driver\n");
229		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
230	}
231
232	return ret;
233}
234postcore_initcall(rpmsg_ctrldev_init);
235
236static void rpmsg_ctrldev_exit(void)
237{
238	unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
239	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
240}
241module_exit(rpmsg_ctrldev_exit);
242
243MODULE_DESCRIPTION("rpmsg control interface");
244MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
245MODULE_LICENSE("GPL v2");
246