GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / rpmsg / rpmsg_ctrl.c
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
33 static dev_t rpmsg_major;
34
35 static DEFINE_IDA(rpmsg_ctrl_ida);
36 static 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  */
48 struct rpmsg_ctrldev {
49         struct rpmsg_device *rpdev;
50         struct cdev cdev;
51         struct device dev;
52         struct mutex ctrl_lock;
53 };
54
55 static 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
65 static 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
74 static 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
121 static 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
129 static void rpmsg_ctrldev_release_device(struct device *dev)
130 {
131         struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
132
133         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
134         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
135         kfree(ctrldev);
136 }
137
138 static 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_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
160         if (ret < 0)
161                 goto free_ctrldev;
162         dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
163
164         ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, 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
181 free_ctrl_ida:
182         ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
183 free_minor_ida:
184         ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
185 free_ctrldev:
186         put_device(dev);
187         kfree(ctrldev);
188
189         return ret;
190 }
191
192 static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
193 {
194         struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
195         int ret;
196
197         /* Destroy all endpoints */
198         ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
199         if (ret)
200                 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
201
202         cdev_device_del(&ctrldev->cdev, &ctrldev->dev);
203         put_device(&ctrldev->dev);
204 }
205
206 static struct rpmsg_driver rpmsg_ctrldev_driver = {
207         .probe = rpmsg_ctrldev_probe,
208         .remove = rpmsg_ctrldev_remove,
209         .drv = {
210                 .name = "rpmsg_ctrl",
211         },
212 };
213
214 static int rpmsg_ctrldev_init(void)
215 {
216         int ret;
217
218         ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_ctrl");
219         if (ret < 0) {
220                 pr_err("failed to allocate char dev region\n");
221                 return ret;
222         }
223
224         ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
225         if (ret < 0) {
226                 pr_err("failed to register rpmsg driver\n");
227                 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
228         }
229
230         return ret;
231 }
232 postcore_initcall(rpmsg_ctrldev_init);
233
234 static void rpmsg_ctrldev_exit(void)
235 {
236         unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
237         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
238 }
239 module_exit(rpmsg_ctrldev_exit);
240
241 MODULE_DESCRIPTION("rpmsg control interface");
242 MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
243 MODULE_LICENSE("GPL v2");