Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/errno.h>
3#include <linux/miscdevice.h> /* for misc_register, and SYNTH_MINOR */
4#include <linux/types.h>
5#include <linux/uaccess.h>
6
7#include "speakup.h"
8#include "spk_priv.h"
9
10#ifndef SYNTH_MINOR
11#define SYNTH_MINOR 25
12#endif
13
14static int misc_registered;
15static int dev_opened;
16
17static ssize_t speakup_file_write(struct file *fp, const char __user *buffer,
18 size_t nbytes, loff_t *ppos)
19{
20 size_t count = nbytes;
21 const char __user *ptr = buffer;
22 size_t bytes;
23 unsigned long flags;
24 u_char buf[256];
25
26 if (!synth)
27 return -ENODEV;
28 while (count > 0) {
29 bytes = min(count, sizeof(buf));
30 if (copy_from_user(buf, ptr, bytes))
31 return -EFAULT;
32 count -= bytes;
33 ptr += bytes;
34 spin_lock_irqsave(&speakup_info.spinlock, flags);
35 synth_write(buf, bytes);
36 spin_unlock_irqrestore(&speakup_info.spinlock, flags);
37 }
38 return (ssize_t)nbytes;
39}
40
41static ssize_t speakup_file_read(struct file *fp, char __user *buf,
42 size_t nbytes, loff_t *ppos)
43{
44 return 0;
45}
46
47static int speakup_file_open(struct inode *ip, struct file *fp)
48{
49 if (!synth)
50 return -ENODEV;
51 if (xchg(&dev_opened, 1))
52 return -EBUSY;
53 return 0;
54}
55
56static int speakup_file_release(struct inode *ip, struct file *fp)
57{
58 dev_opened = 0;
59 return 0;
60}
61
62static const struct file_operations synth_fops = {
63 .read = speakup_file_read,
64 .write = speakup_file_write,
65 .open = speakup_file_open,
66 .release = speakup_file_release,
67};
68
69static struct miscdevice synth_device = {
70 .minor = SYNTH_MINOR,
71 .name = "synth",
72 .fops = &synth_fops,
73};
74
75void speakup_register_devsynth(void)
76{
77 if (misc_registered != 0)
78 return;
79/* zero it so if register fails, deregister will not ref invalid ptrs */
80 if (misc_register(&synth_device)) {
81 pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
82 } else {
83 pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
84 MISC_MAJOR, SYNTH_MINOR);
85 misc_registered = 1;
86 }
87}
88
89void speakup_unregister_devsynth(void)
90{
91 if (!misc_registered)
92 return;
93 pr_info("speakup: unregistering synth device /dev/synth\n");
94 misc_deregister(&synth_device);
95 misc_registered = 0;
96}