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 		ret = rproc_boot(rproc);
36 	} else if (!strncmp(cmd, "stop", len)) {
37 		ret = rproc_shutdown(rproc);
38 	} else if (!strncmp(cmd, "detach", len)) {
39 		ret = rproc_detach(rproc);
40 	} else {
41 		dev_err(&rproc->dev, "Unrecognized option\n");
42 		ret = -EINVAL;
43 	}
44 
45 	return ret ? ret : len;
46 }
47 
48 static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
49 {
50 	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
51 	void __user *argp = (void __user *)arg;
52 	s32 param;
53 
54 	switch (ioctl) {
55 	case RPROC_SET_SHUTDOWN_ON_RELEASE:
56 		if (copy_from_user(&param, argp, sizeof(s32)))
57 			return -EFAULT;
58 
59 		rproc->cdev_put_on_release = !!param;
60 		break;
61 	case RPROC_GET_SHUTDOWN_ON_RELEASE:
62 		param = (s32)rproc->cdev_put_on_release;
63 		if (copy_to_user(argp, &param, sizeof(s32)))
64 			return -EFAULT;
65 
66 		break;
67 	default:
68 		dev_err(&rproc->dev, "Unsupported ioctl\n");
69 		return -EINVAL;
70 	}
71 
72 	return 0;
73 }
74 
75 static int rproc_cdev_release(struct inode *inode, struct file *filp)
76 {
77 	struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
78 	int ret = 0;
79 
80 	if (!rproc->cdev_put_on_release)
81 		return 0;
82 
83 	if (rproc->state == RPROC_RUNNING)
84 		rproc_shutdown(rproc);
85 	else if (rproc->state == RPROC_ATTACHED)
86 		ret = rproc_detach(rproc);
87 
88 	return ret;
89 }
90 
91 static const struct file_operations rproc_fops = {
92 	.write = rproc_cdev_write,
93 	.unlocked_ioctl = rproc_device_ioctl,
94 	.compat_ioctl = compat_ptr_ioctl,
95 	.release = rproc_cdev_release,
96 };
97 
98 int rproc_char_device_add(struct rproc *rproc)
99 {
100 	int ret;
101 
102 	cdev_init(&rproc->cdev, &rproc_fops);
103 	rproc->cdev.owner = THIS_MODULE;
104 
105 	rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
106 	cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
107 	ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
108 	if (ret < 0)
109 		dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
110 
111 	return ret;
112 }
113 
114 void rproc_char_device_remove(struct rproc *rproc)
115 {
116 	cdev_del(&rproc->cdev);
117 }
118 
119 void __init rproc_init_cdev(void)
120 {
121 	int ret;
122 
123 	ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
124 	if (ret < 0)
125 		pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
126 }
127