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