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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Minimalistic braille device kernel support.
4 *
5 * By default, shows console messages on the braille device.
6 * Pressing Insert switches to VC browsing.
7 *
8 * Copyright (C) Samuel Thibault <samuel.thibault@ens-lyon.org>
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/moduleparam.h>
14#include <linux/console.h>
15#include <linux/notifier.h>
16
17#include <linux/selection.h>
18#include <linux/vt_kern.h>
19#include <linux/consolemap.h>
20
21#include <linux/keyboard.h>
22#include <linux/kbd_kern.h>
23#include <linux/input.h>
24
25MODULE_AUTHOR("samuel.thibault@ens-lyon.org");
26MODULE_DESCRIPTION("braille device");
27
28/*
29 * Braille device support part.
30 */
31
32/* Emit various sounds */
33static bool sound;
34module_param(sound, bool, 0);
35MODULE_PARM_DESC(sound, "emit sounds");
36
37static void beep(unsigned int freq)
38{
39 if (sound)
40 kd_mksound(freq, HZ/10);
41}
42
43/* mini console */
44#define WIDTH 40
45#define BRAILLE_KEY KEY_INSERT
46static u16 console_buf[WIDTH];
47static int console_cursor;
48
49/* mini view of VC */
50static int vc_x, vc_y, lastvc_x, lastvc_y;
51
52/* show console ? (or show VC) */
53static int console_show = 1;
54/* pending newline ? */
55static int console_newline = 1;
56static int lastVC = -1;
57
58static struct console *braille_co;
59
60/* Very VisioBraille-specific */
61static void braille_write(u16 *buf)
62{
63 static u16 lastwrite[WIDTH];
64 unsigned char data[1 + 1 + 2*WIDTH + 2 + 1], csum = 0, *c;
65 u16 out;
66 int i;
67
68 if (!braille_co)
69 return;
70
71 if (!memcmp(lastwrite, buf, WIDTH * sizeof(*buf)))
72 return;
73 memcpy(lastwrite, buf, WIDTH * sizeof(*buf));
74
75#define SOH 1
76#define STX 2
77#define ETX 2
78#define EOT 4
79#define ENQ 5
80 data[0] = STX;
81 data[1] = '>';
82 csum ^= '>';
83 c = &data[2];
84 for (i = 0; i < WIDTH; i++) {
85 out = buf[i];
86 if (out >= 0x100)
87 out = '?';
88 else if (out == 0x00)
89 out = ' ';
90 csum ^= out;
91 if (out <= 0x05) {
92 *c++ = SOH;
93 out |= 0x40;
94 }
95 *c++ = out;
96 }
97
98 if (csum <= 0x05) {
99 *c++ = SOH;
100 csum |= 0x40;
101 }
102 *c++ = csum;
103 *c++ = ETX;
104
105 braille_co->write(braille_co, data, c - data);
106}
107
108/* Follow the VC cursor*/
109static void vc_follow_cursor(struct vc_data *vc)
110{
111 vc_x = vc->state.x - (vc->state.x % WIDTH);
112 vc_y = vc->state.y;
113 lastvc_x = vc->state.x;
114 lastvc_y = vc->state.y;
115}
116
117/* Maybe the VC cursor moved, if so follow it */
118static void vc_maybe_cursor_moved(struct vc_data *vc)
119{
120 if (vc->state.x != lastvc_x || vc->state.y != lastvc_y)
121 vc_follow_cursor(vc);
122}
123
124/* Show portion of VC at vc_x, vc_y */
125static void vc_refresh(struct vc_data *vc)
126{
127 u16 buf[WIDTH];
128 int i;
129
130 for (i = 0; i < WIDTH; i++) {
131 u16 glyph = screen_glyph(vc,
132 2 * (vc_x + i) + vc_y * vc->vc_size_row);
133 buf[i] = inverse_translate(vc, glyph, true);
134 }
135 braille_write(buf);
136}
137
138/*
139 * Link to keyboard
140 */
141
142static int keyboard_notifier_call(struct notifier_block *blk,
143 unsigned long code, void *_param)
144{
145 struct keyboard_notifier_param *param = _param;
146 struct vc_data *vc = param->vc;
147 int ret = NOTIFY_OK;
148
149 if (!param->down)
150 return ret;
151
152 switch (code) {
153 case KBD_KEYCODE:
154 if (console_show) {
155 if (param->value == BRAILLE_KEY) {
156 console_show = 0;
157 beep(880);
158 vc_maybe_cursor_moved(vc);
159 vc_refresh(vc);
160 ret = NOTIFY_STOP;
161 }
162 } else {
163 ret = NOTIFY_STOP;
164 switch (param->value) {
165 case KEY_INSERT:
166 beep(440);
167 console_show = 1;
168 lastVC = -1;
169 braille_write(console_buf);
170 break;
171 case KEY_LEFT:
172 if (vc_x > 0) {
173 vc_x -= WIDTH;
174 if (vc_x < 0)
175 vc_x = 0;
176 } else if (vc_y >= 1) {
177 beep(880);
178 vc_y--;
179 vc_x = vc->vc_cols-WIDTH;
180 } else
181 beep(220);
182 break;
183 case KEY_RIGHT:
184 if (vc_x + WIDTH < vc->vc_cols) {
185 vc_x += WIDTH;
186 } else if (vc_y + 1 < vc->vc_rows) {
187 beep(880);
188 vc_y++;
189 vc_x = 0;
190 } else
191 beep(220);
192 break;
193 case KEY_DOWN:
194 if (vc_y + 1 < vc->vc_rows)
195 vc_y++;
196 else
197 beep(220);
198 break;
199 case KEY_UP:
200 if (vc_y >= 1)
201 vc_y--;
202 else
203 beep(220);
204 break;
205 case KEY_HOME:
206 vc_follow_cursor(vc);
207 break;
208 case KEY_PAGEUP:
209 vc_x = 0;
210 vc_y = 0;
211 break;
212 case KEY_PAGEDOWN:
213 vc_x = 0;
214 vc_y = vc->vc_rows-1;
215 break;
216 default:
217 ret = NOTIFY_OK;
218 break;
219 }
220 if (ret == NOTIFY_STOP)
221 vc_refresh(vc);
222 }
223 break;
224 case KBD_POST_KEYSYM:
225 {
226 unsigned char type = KTYP(param->value) - 0xf0;
227
228 if (type == KT_SPEC) {
229 unsigned char val = KVAL(param->value);
230 int on_off = -1;
231
232 switch (val) {
233 case KVAL(K_CAPS):
234 on_off = vt_get_leds(fg_console, VC_CAPSLOCK);
235 break;
236 case KVAL(K_NUM):
237 on_off = vt_get_leds(fg_console, VC_NUMLOCK);
238 break;
239 case KVAL(K_HOLD):
240 on_off = vt_get_leds(fg_console, VC_SCROLLOCK);
241 break;
242 }
243 if (on_off == 1)
244 beep(880);
245 else if (on_off == 0)
246 beep(440);
247 }
248 }
249 break;
250 case KBD_UNBOUND_KEYCODE:
251 case KBD_UNICODE:
252 case KBD_KEYSYM:
253 /* Unused */
254 break;
255 }
256 return ret;
257}
258
259static struct notifier_block keyboard_notifier_block = {
260 .notifier_call = keyboard_notifier_call,
261};
262
263static int vt_notifier_call(struct notifier_block *blk,
264 unsigned long code, void *_param)
265{
266 struct vt_notifier_param *param = _param;
267 struct vc_data *vc = param->vc;
268
269 switch (code) {
270 case VT_ALLOCATE:
271 break;
272 case VT_DEALLOCATE:
273 break;
274 case VT_WRITE:
275 {
276 unsigned char c = param->c;
277
278 if (vc->vc_num != fg_console)
279 break;
280 switch (c) {
281 case '\b':
282 case 127:
283 if (console_cursor > 0) {
284 console_cursor--;
285 console_buf[console_cursor] = ' ';
286 }
287 break;
288 case '\n':
289 case '\v':
290 case '\f':
291 case '\r':
292 console_newline = 1;
293 break;
294 case '\t':
295 c = ' ';
296 fallthrough;
297 default:
298 if (c < 32)
299 /* Ignore other control sequences */
300 break;
301 if (console_newline) {
302 memset(console_buf, 0, sizeof(console_buf));
303 console_cursor = 0;
304 console_newline = 0;
305 }
306 if (console_cursor == WIDTH)
307 memmove(console_buf, &console_buf[1],
308 (WIDTH-1) * sizeof(*console_buf));
309 else
310 console_cursor++;
311 console_buf[console_cursor-1] = c;
312 break;
313 }
314 if (console_show)
315 braille_write(console_buf);
316 else {
317 vc_maybe_cursor_moved(vc);
318 vc_refresh(vc);
319 }
320 break;
321 }
322 case VT_UPDATE:
323 /* Maybe a VT switch, flush */
324 if (console_show) {
325 if (vc->vc_num != lastVC) {
326 lastVC = vc->vc_num;
327 memset(console_buf, 0, sizeof(console_buf));
328 console_cursor = 0;
329 braille_write(console_buf);
330 }
331 } else {
332 vc_maybe_cursor_moved(vc);
333 vc_refresh(vc);
334 }
335 break;
336 }
337 return NOTIFY_OK;
338}
339
340static struct notifier_block vt_notifier_block = {
341 .notifier_call = vt_notifier_call,
342};
343
344/*
345 * Called from printk.c when console=brl is given
346 */
347
348int braille_register_console(struct console *console, int index,
349 char *console_options, char *braille_options)
350{
351 int ret;
352
353 if (!console_options)
354 /* Only support VisioBraille for now */
355 console_options = "57600o8";
356 if (braille_co)
357 return -ENODEV;
358 if (console->setup) {
359 ret = console->setup(console, console_options);
360 if (ret != 0)
361 return ret;
362 }
363 console->flags |= CON_ENABLED;
364 console->index = index;
365 braille_co = console;
366 register_keyboard_notifier(&keyboard_notifier_block);
367 register_vt_notifier(&vt_notifier_block);
368 return 1;
369}
370
371int braille_unregister_console(struct console *console)
372{
373 if (braille_co != console)
374 return -EINVAL;
375 unregister_keyboard_notifier(&keyboard_notifier_block);
376 unregister_vt_notifier(&vt_notifier_block);
377 braille_co = NULL;
378 return 1;
379}
1/*
2 * Minimalistic braille device kernel support.
3 *
4 * By default, shows console messages on the braille device.
5 * Pressing Insert switches to VC browsing.
6 *
7 * Copyright (C) Samuel Thibault <samuel.thibault@ens-lyon.org>
8 *
9 * This program is free software ; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation ; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY ; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with the program ; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/console.h>
28#include <linux/notifier.h>
29
30#include <linux/selection.h>
31#include <linux/vt_kern.h>
32#include <linux/consolemap.h>
33
34#include <linux/keyboard.h>
35#include <linux/kbd_kern.h>
36#include <linux/input.h>
37
38MODULE_AUTHOR("samuel.thibault@ens-lyon.org");
39MODULE_DESCRIPTION("braille device");
40MODULE_LICENSE("GPL");
41
42/*
43 * Braille device support part.
44 */
45
46/* Emit various sounds */
47static bool sound;
48module_param(sound, bool, 0);
49MODULE_PARM_DESC(sound, "emit sounds");
50
51static void beep(unsigned int freq)
52{
53 if (sound)
54 kd_mksound(freq, HZ/10);
55}
56
57/* mini console */
58#define WIDTH 40
59#define BRAILLE_KEY KEY_INSERT
60static u16 console_buf[WIDTH];
61static int console_cursor;
62
63/* mini view of VC */
64static int vc_x, vc_y, lastvc_x, lastvc_y;
65
66/* show console ? (or show VC) */
67static int console_show = 1;
68/* pending newline ? */
69static int console_newline = 1;
70static int lastVC = -1;
71
72static struct console *braille_co;
73
74/* Very VisioBraille-specific */
75static void braille_write(u16 *buf)
76{
77 static u16 lastwrite[WIDTH];
78 unsigned char data[1 + 1 + 2*WIDTH + 2 + 1], csum = 0, *c;
79 u16 out;
80 int i;
81
82 if (!braille_co)
83 return;
84
85 if (!memcmp(lastwrite, buf, WIDTH * sizeof(*buf)))
86 return;
87 memcpy(lastwrite, buf, WIDTH * sizeof(*buf));
88
89#define SOH 1
90#define STX 2
91#define ETX 2
92#define EOT 4
93#define ENQ 5
94 data[0] = STX;
95 data[1] = '>';
96 csum ^= '>';
97 c = &data[2];
98 for (i = 0; i < WIDTH; i++) {
99 out = buf[i];
100 if (out >= 0x100)
101 out = '?';
102 else if (out == 0x00)
103 out = ' ';
104 csum ^= out;
105 if (out <= 0x05) {
106 *c++ = SOH;
107 out |= 0x40;
108 }
109 *c++ = out;
110 }
111
112 if (csum <= 0x05) {
113 *c++ = SOH;
114 csum |= 0x40;
115 }
116 *c++ = csum;
117 *c++ = ETX;
118
119 braille_co->write(braille_co, data, c - data);
120}
121
122/* Follow the VC cursor*/
123static void vc_follow_cursor(struct vc_data *vc)
124{
125 vc_x = vc->vc_x - (vc->vc_x % WIDTH);
126 vc_y = vc->vc_y;
127 lastvc_x = vc->vc_x;
128 lastvc_y = vc->vc_y;
129}
130
131/* Maybe the VC cursor moved, if so follow it */
132static void vc_maybe_cursor_moved(struct vc_data *vc)
133{
134 if (vc->vc_x != lastvc_x || vc->vc_y != lastvc_y)
135 vc_follow_cursor(vc);
136}
137
138/* Show portion of VC at vc_x, vc_y */
139static void vc_refresh(struct vc_data *vc)
140{
141 u16 buf[WIDTH];
142 int i;
143
144 for (i = 0; i < WIDTH; i++) {
145 u16 glyph = screen_glyph(vc,
146 2 * (vc_x + i) + vc_y * vc->vc_size_row);
147 buf[i] = inverse_translate(vc, glyph, 1);
148 }
149 braille_write(buf);
150}
151
152/*
153 * Link to keyboard
154 */
155
156static int keyboard_notifier_call(struct notifier_block *blk,
157 unsigned long code, void *_param)
158{
159 struct keyboard_notifier_param *param = _param;
160 struct vc_data *vc = param->vc;
161 int ret = NOTIFY_OK;
162
163 if (!param->down)
164 return ret;
165
166 switch (code) {
167 case KBD_KEYCODE:
168 if (console_show) {
169 if (param->value == BRAILLE_KEY) {
170 console_show = 0;
171 beep(880);
172 vc_maybe_cursor_moved(vc);
173 vc_refresh(vc);
174 ret = NOTIFY_STOP;
175 }
176 } else {
177 ret = NOTIFY_STOP;
178 switch (param->value) {
179 case KEY_INSERT:
180 beep(440);
181 console_show = 1;
182 lastVC = -1;
183 braille_write(console_buf);
184 break;
185 case KEY_LEFT:
186 if (vc_x > 0) {
187 vc_x -= WIDTH;
188 if (vc_x < 0)
189 vc_x = 0;
190 } else if (vc_y >= 1) {
191 beep(880);
192 vc_y--;
193 vc_x = vc->vc_cols-WIDTH;
194 } else
195 beep(220);
196 break;
197 case KEY_RIGHT:
198 if (vc_x + WIDTH < vc->vc_cols) {
199 vc_x += WIDTH;
200 } else if (vc_y + 1 < vc->vc_rows) {
201 beep(880);
202 vc_y++;
203 vc_x = 0;
204 } else
205 beep(220);
206 break;
207 case KEY_DOWN:
208 if (vc_y + 1 < vc->vc_rows)
209 vc_y++;
210 else
211 beep(220);
212 break;
213 case KEY_UP:
214 if (vc_y >= 1)
215 vc_y--;
216 else
217 beep(220);
218 break;
219 case KEY_HOME:
220 vc_follow_cursor(vc);
221 break;
222 case KEY_PAGEUP:
223 vc_x = 0;
224 vc_y = 0;
225 break;
226 case KEY_PAGEDOWN:
227 vc_x = 0;
228 vc_y = vc->vc_rows-1;
229 break;
230 default:
231 ret = NOTIFY_OK;
232 break;
233 }
234 if (ret == NOTIFY_STOP)
235 vc_refresh(vc);
236 }
237 break;
238 case KBD_POST_KEYSYM:
239 {
240 unsigned char type = KTYP(param->value) - 0xf0;
241 if (type == KT_SPEC) {
242 unsigned char val = KVAL(param->value);
243 int on_off = -1;
244
245 switch (val) {
246 case KVAL(K_CAPS):
247 on_off = vt_get_leds(fg_console, VC_CAPSLOCK);
248 break;
249 case KVAL(K_NUM):
250 on_off = vt_get_leds(fg_console, VC_NUMLOCK);
251 break;
252 case KVAL(K_HOLD):
253 on_off = vt_get_leds(fg_console, VC_SCROLLOCK);
254 break;
255 }
256 if (on_off == 1)
257 beep(880);
258 else if (on_off == 0)
259 beep(440);
260 }
261 }
262 case KBD_UNBOUND_KEYCODE:
263 case KBD_UNICODE:
264 case KBD_KEYSYM:
265 /* Unused */
266 break;
267 }
268 return ret;
269}
270
271static struct notifier_block keyboard_notifier_block = {
272 .notifier_call = keyboard_notifier_call,
273};
274
275static int vt_notifier_call(struct notifier_block *blk,
276 unsigned long code, void *_param)
277{
278 struct vt_notifier_param *param = _param;
279 struct vc_data *vc = param->vc;
280 switch (code) {
281 case VT_ALLOCATE:
282 break;
283 case VT_DEALLOCATE:
284 break;
285 case VT_WRITE:
286 {
287 unsigned char c = param->c;
288 if (vc->vc_num != fg_console)
289 break;
290 switch (c) {
291 case '\b':
292 case 127:
293 if (console_cursor > 0) {
294 console_cursor--;
295 console_buf[console_cursor] = ' ';
296 }
297 break;
298 case '\n':
299 case '\v':
300 case '\f':
301 case '\r':
302 console_newline = 1;
303 break;
304 case '\t':
305 c = ' ';
306 /* Fallthrough */
307 default:
308 if (c < 32)
309 /* Ignore other control sequences */
310 break;
311 if (console_newline) {
312 memset(console_buf, 0, sizeof(console_buf));
313 console_cursor = 0;
314 console_newline = 0;
315 }
316 if (console_cursor == WIDTH)
317 memmove(console_buf, &console_buf[1],
318 (WIDTH-1) * sizeof(*console_buf));
319 else
320 console_cursor++;
321 console_buf[console_cursor-1] = c;
322 break;
323 }
324 if (console_show)
325 braille_write(console_buf);
326 else {
327 vc_maybe_cursor_moved(vc);
328 vc_refresh(vc);
329 }
330 break;
331 }
332 case VT_UPDATE:
333 /* Maybe a VT switch, flush */
334 if (console_show) {
335 if (vc->vc_num != lastVC) {
336 lastVC = vc->vc_num;
337 memset(console_buf, 0, sizeof(console_buf));
338 console_cursor = 0;
339 braille_write(console_buf);
340 }
341 } else {
342 vc_maybe_cursor_moved(vc);
343 vc_refresh(vc);
344 }
345 break;
346 }
347 return NOTIFY_OK;
348}
349
350static struct notifier_block vt_notifier_block = {
351 .notifier_call = vt_notifier_call,
352};
353
354/*
355 * Called from printk.c when console=brl is given
356 */
357
358int braille_register_console(struct console *console, int index,
359 char *console_options, char *braille_options)
360{
361 int ret;
362
363 if (!(console->flags & CON_BRL))
364 return 0;
365 if (!console_options)
366 /* Only support VisioBraille for now */
367 console_options = "57600o8";
368 if (braille_co)
369 return -ENODEV;
370 if (console->setup) {
371 ret = console->setup(console, console_options);
372 if (ret != 0)
373 return ret;
374 }
375 console->flags |= CON_ENABLED;
376 console->index = index;
377 braille_co = console;
378 register_keyboard_notifier(&keyboard_notifier_block);
379 register_vt_notifier(&vt_notifier_block);
380 return 1;
381}
382
383int braille_unregister_console(struct console *console)
384{
385 if (braille_co != console)
386 return -EINVAL;
387 if (!(console->flags & CON_BRL))
388 return 0;
389 unregister_keyboard_notifier(&keyboard_notifier_block);
390 unregister_vt_notifier(&vt_notifier_block);
391 braille_co = NULL;
392 return 1;
393}