| William Hubbs | c6e3fd2 | 2010-10-07 13:20:02 -0500 | [diff] [blame^] | 1 | #include <linux/console.h> |
| 2 | #include <linux/smp_lock.h> |
| 3 | #include <linux/types.h> |
| 4 | #include <linux/wait.h> |
| 5 | |
| 6 | #include "speakup.h" |
| 7 | #include "spk_priv.h" |
| 8 | |
| 9 | #define synthBufferSize 8192 /* currently 8K bytes */ |
| 10 | |
| 11 | static u_char synth_buffer[synthBufferSize]; /* guess what this is for! */ |
| 12 | static u_char *buff_in = synth_buffer; |
| 13 | static u_char *buff_out = synth_buffer; |
| 14 | static u_char *buffer_end = synth_buffer+synthBufferSize-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 | */ |
| 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 != NULL) && (vc_cons[i].d->vc_tty != NULL)) |
| 32 | start_tty(vc_cons[i].d->vc_tty); |
| 33 | } |
| 34 | } |
| 35 | EXPORT_SYMBOL_GPL(speakup_start_ttys); |
| 36 | |
| 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 != NULL) && (vc_cons[i].d->vc_tty != NULL)) |
| 43 | stop_tty(vc_cons[i].d->vc_tty); |
| 44 | return; |
| 45 | } |
| 46 | |
| 47 | static int synth_buffer_free(void) |
| 48 | { |
| 49 | int bytesFree; |
| 50 | |
| 51 | if (buff_in >= buff_out) |
| 52 | bytesFree = synthBufferSize - (buff_in - buff_out); |
| 53 | else |
| 54 | bytesFree = buff_out - buff_in; |
| 55 | return bytesFree; |
| 56 | } |
| 57 | |
| 58 | int synth_buffer_empty(void) |
| 59 | { |
| 60 | return (buff_in == buff_out); |
| 61 | } |
| 62 | EXPORT_SYMBOL_GPL(synth_buffer_empty); |
| 63 | |
| 64 | void synth_buffer_add(char ch) |
| 65 | { |
| 66 | if (!synth->alive) { |
| 67 | /* This makes sure that we won't stop TTYs if there is no synth |
| 68 | * to restart them */ |
| 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 | |
| 82 | char synth_buffer_getc(void) |
| 83 | { |
| 84 | char 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 | } |
| 93 | EXPORT_SYMBOL_GPL(synth_buffer_getc); |
| 94 | |
| 95 | char synth_buffer_peek(void) |
| 96 | { |
| 97 | if (buff_out == buff_in) |
| 98 | return 0; |
| 99 | return *buff_out; |
| 100 | } |
| 101 | EXPORT_SYMBOL_GPL(synth_buffer_peek); |
| 102 | |
| 103 | void synth_buffer_clear(void) |
| 104 | { |
| 105 | buff_in = buff_out = synth_buffer; |
| 106 | return; |
| 107 | } |
| 108 | EXPORT_SYMBOL_GPL(synth_buffer_clear); |