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