tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
19static dev_t rproc_major;
20
21static 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
52static 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(¶m, 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, ¶m, 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
79static 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
89static 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
96int 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
112void rproc_char_device_remove(struct rproc *rproc)
113{
114 __unregister_chrdev(MAJOR(rproc->dev.devt), rproc->index, 1, "remoteproc");
115}
116
117void __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}