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
10 static int misc_registered;
11 static int dev_opened;
12
speakup_file_write(struct file * fp,const char __user * buffer,size_t nbytes,loff_t * ppos)13 static 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
speakup_file_read(struct file * fp,char __user * buf,size_t nbytes,loff_t * ppos)37 static ssize_t speakup_file_read(struct file *fp, char __user *buf,
38 size_t nbytes, loff_t *ppos)
39 {
40 return 0;
41 }
42
speakup_file_open(struct inode * ip,struct file * fp)43 static 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
speakup_file_release(struct inode * ip,struct file * fp)52 static int speakup_file_release(struct inode *ip, struct file *fp)
53 {
54 dev_opened = 0;
55 return 0;
56 }
57
58 static 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
65 static struct miscdevice synth_device = {
66 .minor = MISC_DYNAMIC_MINOR,
67 .name = "synth",
68 .fops = &synth_fops,
69 };
70
speakup_register_devsynth(void)71 void 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
speakup_unregister_devsynth(void)85 void 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 }
93