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 		    rproc->state == RPROC_ATTACHED)
37 			return -EBUSY;
38 
39 		ret = rproc_boot(rproc);
40 	} else if (!strncmp(cmd, "stop", len)) {
41 		if (rproc->state != RPROC_RUNNING &&
42 		    rproc->state != RPROC_ATTACHED)
43 			return -EINVAL;
44 
45 		rproc_shutdown(rproc);
46 	} else if (!strncmp(cmd, "detach", len)) {
47 		if (rproc->state != RPROC_ATTACHED)
48 			return -EINVAL;
49 
50 		ret = rproc_detach(rproc);
51 	} else {
52 		dev_err(&rproc->dev, "Unrecognized option\n");
53 		ret = -EINVAL;
54 	}
55 
56 	return ret ? ret : len;
57 }
58 
59 static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
60 {
61 	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
62 	void __user *argp = (void __user *)arg;
63 	s32 param;
64 
65 	switch (ioctl) {
66 	case RPROC_SET_SHUTDOWN_ON_RELEASE:
67 		if (copy_from_user(&param, argp, sizeof(s32)))
68 			return -EFAULT;
69 
70 		rproc->cdev_put_on_release = !!param;
71 		break;
72 	case RPROC_GET_SHUTDOWN_ON_RELEASE:
73 		param = (s32)rproc->cdev_put_on_release;
74 		if (copy_to_user(argp, &param, sizeof(s32)))
75 			return -EFAULT;
76 
77 		break;
78 	default:
79 		dev_err(&rproc->dev, "Unsupported ioctl\n");
80 		return -EINVAL;
81 	}
82 
83 	return 0;
84 }
85 
86 static int rproc_cdev_release(struct inode *inode, struct file *filp)
87 {
88 	struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
89 	int ret = 0;
90 
91 	if (!rproc->cdev_put_on_release)
92 		return 0;
93 
94 	if (rproc->state == RPROC_RUNNING)
95 		rproc_shutdown(rproc);
96 	else if (rproc->state == RPROC_ATTACHED)
97 		ret = rproc_detach(rproc);
98 
99 	return ret;
100 }
101 
102 static const struct file_operations rproc_fops = {
103 	.write = rproc_cdev_write,
104 	.unlocked_ioctl = rproc_device_ioctl,
105 	.compat_ioctl = compat_ptr_ioctl,
106 	.release = rproc_cdev_release,
107 };
108 
109 int rproc_char_device_add(struct rproc *rproc)
110 {
111 	int ret;
112 
113 	cdev_init(&rproc->cdev, &rproc_fops);
114 	rproc->cdev.owner = THIS_MODULE;
115 
116 	rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
117 	cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
118 	ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
119 	if (ret < 0)
120 		dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
121 
122 	return ret;
123 }
124 
125 void rproc_char_device_remove(struct rproc *rproc)
126 {
127 	cdev_del(&rproc->cdev);
128 }
129 
130 void __init rproc_init_cdev(void)
131 {
132 	int ret;
133 
134 	ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
135 	if (ret < 0)
136 		pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
137 }
138