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