1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Character device interface driver for Remoteproc framework.
4  *
5  * Copyright (c) 2020, The Linux Foundation. All rights reserved.
6  */
7 
8 #include <linux/cdev.h>
9 #include <linux/compat.h>
10 #include <linux/fs.h>
11 #include <linux/module.h>
12 #include <linux/remoteproc.h>
13 #include <linux/uaccess.h>
14 #include <uapi/linux/remoteproc_cdev.h>
15 
16 #include "remoteproc_internal.h"
17 
18 #define NUM_RPROC_DEVICES	64
19 static dev_t rproc_major;
20 
21 static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_t len, loff_t *pos)
22 {
23 	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
24 	int ret = 0;
25 	char cmd[10];
26 
27 	if (!len || len > sizeof(cmd))
28 		return -EINVAL;
29 
30 	ret = copy_from_user(cmd, buf, len);
31 	if (ret)
32 		return -EFAULT;
33 
34 	if (!strncmp(cmd, "start", len)) {
35 		if (rproc->state == RPROC_RUNNING)
36 			return -EBUSY;
37 
38 		ret = rproc_boot(rproc);
39 	} else if (!strncmp(cmd, "stop", len)) {
40 		if (rproc->state != RPROC_RUNNING)
41 			return -EINVAL;
42 
43 		rproc_shutdown(rproc);
44 	} else {
45 		dev_err(&rproc->dev, "Unrecognized option\n");
46 		ret = -EINVAL;
47 	}
48 
49 	return ret ? ret : len;
50 }
51 
52 static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
53 {
54 	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
55 	void __user *argp = (void __user *)arg;
56 	s32 param;
57 
58 	switch (ioctl) {
59 	case RPROC_SET_SHUTDOWN_ON_RELEASE:
60 		if (copy_from_user(&param, argp, sizeof(s32)))
61 			return -EFAULT;
62 
63 		rproc->cdev_put_on_release = !!param;
64 		break;
65 	case RPROC_GET_SHUTDOWN_ON_RELEASE:
66 		param = (s32)rproc->cdev_put_on_release;
67 		if (copy_to_user(argp, &param, sizeof(s32)))
68 			return -EFAULT;
69 
70 		break;
71 	default:
72 		dev_err(&rproc->dev, "Unsupported ioctl\n");
73 		return -EINVAL;
74 	}
75 
76 	return 0;
77 }
78 
79 static int rproc_cdev_release(struct inode *inode, struct file *filp)
80 {
81 	struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
82 
83 	if (rproc->cdev_put_on_release && rproc->state == RPROC_RUNNING)
84 		rproc_shutdown(rproc);
85 
86 	return 0;
87 }
88 
89 static const struct file_operations rproc_fops = {
90 	.write = rproc_cdev_write,
91 	.unlocked_ioctl = rproc_device_ioctl,
92 	.compat_ioctl = compat_ptr_ioctl,
93 	.release = rproc_cdev_release,
94 };
95 
96 int rproc_char_device_add(struct rproc *rproc)
97 {
98 	int ret;
99 
100 	cdev_init(&rproc->cdev, &rproc_fops);
101 	rproc->cdev.owner = THIS_MODULE;
102 
103 	rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
104 	cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
105 	ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
106 	if (ret < 0)
107 		dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
108 
109 	return ret;
110 }
111 
112 void rproc_char_device_remove(struct rproc *rproc)
113 {
114 	__unregister_chrdev(MAJOR(rproc->dev.devt), rproc->index, 1, "remoteproc");
115 }
116 
117 void __init rproc_init_cdev(void)
118 {
119 	int ret;
120 
121 	ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
122 	if (ret < 0)
123 		pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
124 }
125