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 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
rproc_device_ioctl(struct file * filp,unsigned int ioctl,unsigned long arg)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(¶m, 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, ¶m, 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
rproc_cdev_release(struct inode * inode,struct file * filp)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
rproc_char_device_add(struct rproc * rproc)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
rproc_char_device_remove(struct rproc * rproc)114 void rproc_char_device_remove(struct rproc *rproc)
115 {
116 cdev_del(&rproc->cdev);
117 }
118
rproc_init_cdev(void)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
