tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/console.h>
3#include <linux/types.h>
4#include <linux/wait.h>
5
6#include "speakup.h"
7#include "spk_priv.h"
8
9#define SYNTH_BUF_SIZE 8192 /* currently 8K bytes */
10
11static u16 synth_buffer[SYNTH_BUF_SIZE]; /* guess what this is for! */
12static u16 *buff_in = synth_buffer;
13static u16 *buff_out = synth_buffer;
14static u16 *buffer_end = synth_buffer + SYNTH_BUF_SIZE - 1;
15
16/* These try to throttle applications by stopping the TTYs
17 * Note: we need to make sure that we will restart them eventually, which is
18 * usually not possible to do from the notifiers. TODO: it should be possible
19 * starting from linux 2.6.26.
20 *
21 * So we only stop when we know alive == 1 (else we discard the data anyway),
22 * and the alive synth will eventually call start_ttys from the thread context.
23 */
24void speakup_start_ttys(void)
25{
26 int i;
27
28 for (i = 0; i < MAX_NR_CONSOLES; i++) {
29 if (speakup_console[i] && speakup_console[i]->tty_stopped)
30 continue;
31 if (vc_cons[i].d && vc_cons[i].d->port.tty)
32 start_tty(vc_cons[i].d->port.tty);
33 }
34}
35EXPORT_SYMBOL_GPL(speakup_start_ttys);
36
37static void speakup_stop_ttys(void)
38{
39 int i;
40
41 for (i = 0; i < MAX_NR_CONSOLES; i++)
42 if (vc_cons[i].d && vc_cons[i].d->port.tty)
43 stop_tty(vc_cons[i].d->port.tty);
44}
45
46static int synth_buffer_free(void)
47{
48 int chars_free;
49
50 if (buff_in >= buff_out)
51 chars_free = SYNTH_BUF_SIZE - (buff_in - buff_out);
52 else
53 chars_free = buff_out - buff_in;
54 return chars_free;
55}
56
57int synth_buffer_empty(void)
58{
59 return (buff_in == buff_out);
60}
61EXPORT_SYMBOL_GPL(synth_buffer_empty);
62
63void synth_buffer_add(u16 ch)
64{
65 if (!synth->alive) {
66 /* This makes sure that we won't stop TTYs if there is no synth
67 * to restart them
68 */
69 return;
70 }
71 if (synth_buffer_free() <= 100) {
72 synth_start();
73 speakup_stop_ttys();
74 }
75 if (synth_buffer_free() <= 1)
76 return;
77 *buff_in++ = ch;
78 if (buff_in > buffer_end)
79 buff_in = synth_buffer;
80}
81
82u16 synth_buffer_getc(void)
83{
84 u16 ch;
85
86 if (buff_out == buff_in)
87 return 0;
88 ch = *buff_out++;
89 if (buff_out > buffer_end)
90 buff_out = synth_buffer;
91 return ch;
92}
93EXPORT_SYMBOL_GPL(synth_buffer_getc);
94
95u16 synth_buffer_peek(void)
96{
97 if (buff_out == buff_in)
98 return 0;
99 return *buff_out;
100}
101EXPORT_SYMBOL_GPL(synth_buffer_peek);
102
103void synth_buffer_skip_nonlatin1(void)
104{
105 while (buff_out != buff_in) {
106 if (*buff_out < 0x100)
107 return;
108 buff_out++;
109 if (buff_out > buffer_end)
110 buff_out = synth_buffer;
111 }
112}
113EXPORT_SYMBOL_GPL(synth_buffer_skip_nonlatin1);
114
115void synth_buffer_clear(void)
116{
117 buff_in = synth_buffer;
118 buff_out = synth_buffer;
119}
120EXPORT_SYMBOL_GPL(synth_buffer_clear);