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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - drivers/staging/speakup/buffers.c
1 #include <linux/console.h>
2 #include <linux/types.h>
3 #include <linux/wait.h>
8 #define SYNTH_BUF_SIZE 8192 /* currently 8K bytes */
10 static u_char synth_buffer
[SYNTH_BUF_SIZE
]; /* guess what this is for! */
11 static u_char
*buff_in
= synth_buffer
;
12 static u_char
*buff_out
= synth_buffer
;
13 static u_char
*buffer_end
= synth_buffer
+ SYNTH_BUF_SIZE
- 1;
15 /* These try to throttle applications by stopping the TTYs
16 * Note: we need to make sure that we will restart them eventually, which is
17 * usually not possible to do from the notifiers. TODO: it should be possible
18 * starting from linux 2.6.26.
20 * So we only stop when we know alive == 1 (else we discard the data anyway),
21 * and the alive synth will eventually call start_ttys from the thread context.
23 void speakup_start_ttys(void)
27 for (i
= 0; i
< MAX_NR_CONSOLES
; i
++) {
28 if (speakup_console
[i
] && speakup_console
[i
]->tty_stopped
)
30 if ((vc_cons
[i
].d
!= NULL
) && (vc_cons
[i
].d
->port
.tty
!= NULL
))
31 start_tty(vc_cons
[i
].d
->port
.tty
);
34 EXPORT_SYMBOL_GPL(speakup_start_ttys
);
36 static void speakup_stop_ttys(void)
40 for (i
= 0; i
< MAX_NR_CONSOLES
; i
++)
41 if ((vc_cons
[i
].d
!= NULL
) && (vc_cons
[i
].d
->port
.tty
!= NULL
))
42 stop_tty(vc_cons
[i
].d
->port
.tty
);
45 static int synth_buffer_free(void)
49 if (buff_in
>= buff_out
)
50 bytes_free
= SYNTH_BUF_SIZE
- (buff_in
- buff_out
);
52 bytes_free
= buff_out
- buff_in
;
56 int synth_buffer_empty(void)
58 return (buff_in
== buff_out
);
60 EXPORT_SYMBOL_GPL(synth_buffer_empty
);
62 void synth_buffer_add(char ch
)
65 /* This makes sure that we won't stop TTYs if there is no synth
69 if (synth_buffer_free() <= 100) {
73 if (synth_buffer_free() <= 1)
76 if (buff_in
> buffer_end
)
77 buff_in
= synth_buffer
;
80 char synth_buffer_getc(void)
84 if (buff_out
== buff_in
)
87 if (buff_out
> buffer_end
)
88 buff_out
= synth_buffer
;
91 EXPORT_SYMBOL_GPL(synth_buffer_getc
);
93 char synth_buffer_peek(void)
95 if (buff_out
== buff_in
)
99 EXPORT_SYMBOL_GPL(synth_buffer_peek
);
101 void synth_buffer_clear(void)
103 buff_in
= buff_out
= synth_buffer
;
105 EXPORT_SYMBOL_GPL(synth_buffer_clear
);