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
rproc_cdev_write(struct file * filp,const char __user * buf,size_t len,loff_t * pos)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
rproc_device_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)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(¶m, 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, ¶m, 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
rproc_cdev_release(struct inode * inode,struct file * filp)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
rproc_char_device_add(struct rproc * rproc)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
rproc_char_device_remove(struct rproc * rproc)125 void rproc_char_device_remove(struct rproc *rproc)
126 {
127 cdev_del(&rproc->cdev);
128 }
129
rproc_init_cdev(void)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
