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
14 static int misc_registered;
15 static int dev_opened;
16
speakup_file_write(struct file * fp,const char __user * buffer,size_t nbytes,loff_t * ppos)17 static 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
speakup_file_read(struct file * fp,char __user * buf,size_t nbytes,loff_t * ppos)41 static ssize_t speakup_file_read(struct file *fp, char __user *buf,
42 size_t nbytes, loff_t *ppos)
43 {
44 return 0;
45 }
46
speakup_file_open(struct inode * ip,struct file * fp)47 static 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
speakup_file_release(struct inode * ip,struct file * fp)56 static int speakup_file_release(struct inode *ip, struct file *fp)
57 {
58 dev_opened = 0;
59 return 0;
60 }
61
62 static 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
69 static struct miscdevice synth_device = {
70 .minor = SYNTH_MINOR,
71 .name = "synth",
72 .fops = &synth_fops,
73 };
74
speakup_register_devsynth(void)75 void 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
speakup_unregister_devsynth(void)89 void 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 }
97
