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
13 static int misc_registered;
14 static int dev_opened;
15
speakup_file_write(struct file * fp,const char * buffer,size_t nbytes,loff_t * ppos)16 static 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
speakup_file_read(struct file * fp,char * buf,size_t nbytes,loff_t * ppos)40 static ssize_t speakup_file_read(struct file *fp, char *buf, size_t nbytes,
41 loff_t *ppos)
42 {
43 return 0;
44 }
45
speakup_file_open(struct inode * ip,struct file * fp)46 static 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
speakup_file_release(struct inode * ip,struct file * fp)55 static int speakup_file_release(struct inode *ip, struct file *fp)
56 {
57 dev_opened = 0;
58 return 0;
59 }
60
61 static 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
68 static struct miscdevice synth_device = {
69 .minor = SYNTH_MINOR,
70 .name = "synth",
71 .fops = &synth_fops,
72 };
73
speakup_register_devsynth(void)74 void 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
speakup_unregister_devsynth(void)88 void 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 }
96