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 
11 static u16 synth_buffer[SYNTH_BUF_SIZE];	/* guess what this is for! */
12 static u16 *buff_in = synth_buffer;
13 static u16 *buff_out = synth_buffer;
14 static 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  */
speakup_start_ttys(void)24 void 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 }
35 EXPORT_SYMBOL_GPL(speakup_start_ttys);
36 
speakup_stop_ttys(void)37 static 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 
synth_buffer_free(void)46 static 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 
synth_buffer_empty(void)57 int synth_buffer_empty(void)
58 {
59 	return (buff_in == buff_out);
60 }
61 EXPORT_SYMBOL_GPL(synth_buffer_empty);
62 
synth_buffer_add(u16 ch)63 void 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 	/* We have written something to the speech synthesis, so we are not
81 	 * paused any more.
82 	 */
83 	spk_paused = false;
84 }
85 
synth_buffer_getc(void)86 u16 synth_buffer_getc(void)
87 {
88 	u16 ch;
89 
90 	if (buff_out == buff_in)
91 		return 0;
92 	ch = *buff_out++;
93 	if (buff_out > buffer_end)
94 		buff_out = synth_buffer;
95 	return ch;
96 }
97 EXPORT_SYMBOL_GPL(synth_buffer_getc);
98 
synth_buffer_peek(void)99 u16 synth_buffer_peek(void)
100 {
101 	if (buff_out == buff_in)
102 		return 0;
103 	return *buff_out;
104 }
105 EXPORT_SYMBOL_GPL(synth_buffer_peek);
106 
synth_buffer_skip_nonlatin1(void)107 void synth_buffer_skip_nonlatin1(void)
108 {
109 	while (buff_out != buff_in) {
110 		if (*buff_out < 0x100)
111 			return;
112 		buff_out++;
113 		if (buff_out > buffer_end)
114 			buff_out = synth_buffer;
115 	}
116 }
117 EXPORT_SYMBOL_GPL(synth_buffer_skip_nonlatin1);
118 
synth_buffer_clear(void)119 void synth_buffer_clear(void)
120 {
121 	buff_in = synth_buffer;
122 	buff_out = synth_buffer;
123 }
124 EXPORT_SYMBOL_GPL(synth_buffer_clear);
125