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