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 | |
25 | MODULE_AUTHOR("samuel.thibault@ens-lyon.org" ); |
26 | MODULE_DESCRIPTION("braille device" ); |
27 | |
28 | /* |
29 | * Braille device support part. |
30 | */ |
31 | |
32 | /* Emit various sounds */ |
33 | static bool sound; |
34 | module_param(sound, bool, 0); |
35 | MODULE_PARM_DESC(sound, "emit sounds" ); |
36 | |
37 | static void beep(unsigned int freq) |
38 | { |
39 | if (sound) |
40 | kd_mksound(hz: freq, HZ/10); |
41 | } |
42 | |
43 | /* mini console */ |
44 | #define WIDTH 40 |
45 | #define BRAILLE_KEY KEY_INSERT |
46 | static u16 console_buf[WIDTH]; |
47 | static int console_cursor; |
48 | |
49 | /* mini view of VC */ |
50 | static int vc_x, vc_y, lastvc_x, lastvc_y; |
51 | |
52 | /* show console ? (or show VC) */ |
53 | static int console_show = 1; |
54 | /* pending newline ? */ |
55 | static int console_newline = 1; |
56 | static int lastVC = -1; |
57 | |
58 | static struct console *braille_co; |
59 | |
60 | /* Very VisioBraille-specific */ |
61 | static 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(p: lastwrite, q: 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*/ |
109 | static 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 */ |
118 | static 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 */ |
125 | static 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 | offset: 2 * (vc_x + i) + vc_y * vc->vc_size_row); |
133 | buf[i] = inverse_translate(conp: vc, glyph, use_unicode: true); |
134 | } |
135 | braille_write(buf); |
136 | } |
137 | |
138 | /* |
139 | * Link to keyboard |
140 | */ |
141 | |
142 | static 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(freq: 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(freq: 440); |
167 | console_show = 1; |
168 | lastVC = -1; |
169 | braille_write(buf: 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(freq: 880); |
178 | vc_y--; |
179 | vc_x = vc->vc_cols-WIDTH; |
180 | } else |
181 | beep(freq: 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(freq: 880); |
188 | vc_y++; |
189 | vc_x = 0; |
190 | } else |
191 | beep(freq: 220); |
192 | break; |
193 | case KEY_DOWN: |
194 | if (vc_y + 1 < vc->vc_rows) |
195 | vc_y++; |
196 | else |
197 | beep(freq: 220); |
198 | break; |
199 | case KEY_UP: |
200 | if (vc_y >= 1) |
201 | vc_y--; |
202 | else |
203 | beep(freq: 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(console: fg_console, VC_CAPSLOCK); |
235 | break; |
236 | case KVAL(K_NUM): |
237 | on_off = vt_get_leds(console: fg_console, VC_NUMLOCK); |
238 | break; |
239 | case KVAL(K_HOLD): |
240 | on_off = vt_get_leds(console: fg_console, VC_SCROLLOCK); |
241 | break; |
242 | } |
243 | if (on_off == 1) |
244 | beep(freq: 880); |
245 | else if (on_off == 0) |
246 | beep(freq: 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 | |
259 | static struct notifier_block keyboard_notifier_block = { |
260 | .notifier_call = keyboard_notifier_call, |
261 | }; |
262 | |
263 | static 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(buf: 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(buf: 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 | |
340 | static 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 | |
348 | int 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(nb: &keyboard_notifier_block); |
367 | register_vt_notifier(nb: &vt_notifier_block); |
368 | return 1; |
369 | } |
370 | |
371 | int braille_unregister_console(struct console *console) |
372 | { |
373 | if (braille_co != console) |
374 | return -EINVAL; |
375 | unregister_keyboard_notifier(nb: &keyboard_notifier_block); |
376 | unregister_vt_notifier(nb: &vt_notifier_block); |
377 | braille_co = NULL; |
378 | return 1; |
379 | } |
380 | |