380 lines
7.3 KiB
C
380 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Minimalistic braille device kernel support.
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*
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* By default, shows console messages on the braille device.
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* Pressing Insert switches to VC browsing.
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*
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* Copyright (C) Samuel Thibault <samuel.thibault@ens-lyon.org>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/console.h>
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#include <linux/notifier.h>
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#include <linux/selection.h>
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#include <linux/vt_kern.h>
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#include <linux/consolemap.h>
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#include <linux/keyboard.h>
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#include <linux/kbd_kern.h>
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#include <linux/input.h>
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MODULE_AUTHOR("samuel.thibault@ens-lyon.org");
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MODULE_DESCRIPTION("braille device");
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/*
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* Braille device support part.
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*/
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/* Emit various sounds */
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static bool sound;
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module_param(sound, bool, 0);
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MODULE_PARM_DESC(sound, "emit sounds");
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static void beep(unsigned int freq)
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{
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if (sound)
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kd_mksound(freq, HZ/10);
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}
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/* mini console */
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#define WIDTH 40
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#define BRAILLE_KEY KEY_INSERT
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static u16 console_buf[WIDTH];
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static int console_cursor;
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/* mini view of VC */
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static int vc_x, vc_y, lastvc_x, lastvc_y;
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/* show console ? (or show VC) */
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static int console_show = 1;
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/* pending newline ? */
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static int console_newline = 1;
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static int lastVC = -1;
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static struct console *braille_co;
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/* Very VisioBraille-specific */
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static void braille_write(u16 *buf)
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{
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static u16 lastwrite[WIDTH];
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unsigned char data[1 + 1 + 2*WIDTH + 2 + 1], csum = 0, *c;
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u16 out;
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int i;
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if (!braille_co)
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return;
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if (!memcmp(lastwrite, buf, WIDTH * sizeof(*buf)))
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return;
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memcpy(lastwrite, buf, WIDTH * sizeof(*buf));
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#define SOH 1
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#define STX 2
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#define ETX 2
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#define EOT 4
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#define ENQ 5
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data[0] = STX;
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data[1] = '>';
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csum ^= '>';
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c = &data[2];
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for (i = 0; i < WIDTH; i++) {
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out = buf[i];
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if (out >= 0x100)
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out = '?';
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else if (out == 0x00)
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out = ' ';
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csum ^= out;
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if (out <= 0x05) {
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*c++ = SOH;
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out |= 0x40;
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}
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*c++ = out;
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}
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if (csum <= 0x05) {
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*c++ = SOH;
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csum |= 0x40;
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}
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*c++ = csum;
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*c++ = ETX;
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braille_co->write(braille_co, data, c - data);
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}
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/* Follow the VC cursor*/
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static void vc_follow_cursor(struct vc_data *vc)
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{
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vc_x = vc->state.x - (vc->state.x % WIDTH);
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vc_y = vc->state.y;
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lastvc_x = vc->state.x;
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lastvc_y = vc->state.y;
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}
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/* Maybe the VC cursor moved, if so follow it */
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static void vc_maybe_cursor_moved(struct vc_data *vc)
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{
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if (vc->state.x != lastvc_x || vc->state.y != lastvc_y)
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vc_follow_cursor(vc);
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}
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/* Show portion of VC at vc_x, vc_y */
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static void vc_refresh(struct vc_data *vc)
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{
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u16 buf[WIDTH];
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int i;
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for (i = 0; i < WIDTH; i++) {
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u16 glyph = screen_glyph(vc,
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2 * (vc_x + i) + vc_y * vc->vc_size_row);
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buf[i] = inverse_translate(vc, glyph, true);
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}
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braille_write(buf);
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}
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/*
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* Link to keyboard
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*/
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static int keyboard_notifier_call(struct notifier_block *blk,
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unsigned long code, void *_param)
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{
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struct keyboard_notifier_param *param = _param;
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struct vc_data *vc = param->vc;
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int ret = NOTIFY_OK;
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if (!param->down)
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return ret;
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switch (code) {
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case KBD_KEYCODE:
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if (console_show) {
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if (param->value == BRAILLE_KEY) {
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console_show = 0;
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beep(880);
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vc_maybe_cursor_moved(vc);
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vc_refresh(vc);
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ret = NOTIFY_STOP;
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}
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} else {
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ret = NOTIFY_STOP;
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switch (param->value) {
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case KEY_INSERT:
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beep(440);
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console_show = 1;
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lastVC = -1;
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braille_write(console_buf);
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break;
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case KEY_LEFT:
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if (vc_x > 0) {
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vc_x -= WIDTH;
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if (vc_x < 0)
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vc_x = 0;
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} else if (vc_y >= 1) {
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beep(880);
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vc_y--;
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vc_x = vc->vc_cols-WIDTH;
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} else
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beep(220);
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break;
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case KEY_RIGHT:
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if (vc_x + WIDTH < vc->vc_cols) {
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vc_x += WIDTH;
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} else if (vc_y + 1 < vc->vc_rows) {
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beep(880);
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vc_y++;
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vc_x = 0;
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} else
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beep(220);
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break;
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case KEY_DOWN:
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if (vc_y + 1 < vc->vc_rows)
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vc_y++;
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else
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beep(220);
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break;
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case KEY_UP:
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if (vc_y >= 1)
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vc_y--;
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else
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beep(220);
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break;
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case KEY_HOME:
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vc_follow_cursor(vc);
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break;
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case KEY_PAGEUP:
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vc_x = 0;
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vc_y = 0;
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break;
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case KEY_PAGEDOWN:
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vc_x = 0;
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vc_y = vc->vc_rows-1;
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break;
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default:
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ret = NOTIFY_OK;
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break;
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}
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if (ret == NOTIFY_STOP)
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vc_refresh(vc);
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}
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break;
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case KBD_POST_KEYSYM:
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{
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unsigned char type = KTYP(param->value) - 0xf0;
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if (type == KT_SPEC) {
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unsigned char val = KVAL(param->value);
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int on_off = -1;
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switch (val) {
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case KVAL(K_CAPS):
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on_off = vt_get_leds(fg_console, VC_CAPSLOCK);
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break;
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case KVAL(K_NUM):
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on_off = vt_get_leds(fg_console, VC_NUMLOCK);
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break;
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case KVAL(K_HOLD):
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on_off = vt_get_leds(fg_console, VC_SCROLLOCK);
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break;
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}
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if (on_off == 1)
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beep(880);
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else if (on_off == 0)
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beep(440);
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}
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}
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break;
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case KBD_UNBOUND_KEYCODE:
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case KBD_UNICODE:
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case KBD_KEYSYM:
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/* Unused */
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break;
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}
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return ret;
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}
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static struct notifier_block keyboard_notifier_block = {
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.notifier_call = keyboard_notifier_call,
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};
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static int vt_notifier_call(struct notifier_block *blk,
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unsigned long code, void *_param)
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{
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struct vt_notifier_param *param = _param;
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struct vc_data *vc = param->vc;
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switch (code) {
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case VT_ALLOCATE:
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break;
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case VT_DEALLOCATE:
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break;
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case VT_WRITE:
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{
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unsigned char c = param->c;
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if (vc->vc_num != fg_console)
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break;
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switch (c) {
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case '\b':
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case 127:
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if (console_cursor > 0) {
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console_cursor--;
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console_buf[console_cursor] = ' ';
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}
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break;
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case '\n':
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case '\v':
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case '\f':
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case '\r':
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console_newline = 1;
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break;
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case '\t':
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c = ' ';
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fallthrough;
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default:
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if (c < 32)
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/* Ignore other control sequences */
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break;
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if (console_newline) {
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memset(console_buf, 0, sizeof(console_buf));
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console_cursor = 0;
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console_newline = 0;
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}
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if (console_cursor == WIDTH)
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memmove(console_buf, &console_buf[1],
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(WIDTH-1) * sizeof(*console_buf));
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else
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console_cursor++;
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console_buf[console_cursor-1] = c;
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break;
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}
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if (console_show)
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braille_write(console_buf);
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else {
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vc_maybe_cursor_moved(vc);
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vc_refresh(vc);
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}
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break;
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}
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case VT_UPDATE:
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/* Maybe a VT switch, flush */
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if (console_show) {
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if (vc->vc_num != lastVC) {
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lastVC = vc->vc_num;
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memset(console_buf, 0, sizeof(console_buf));
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console_cursor = 0;
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braille_write(console_buf);
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}
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} else {
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vc_maybe_cursor_moved(vc);
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vc_refresh(vc);
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}
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block vt_notifier_block = {
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.notifier_call = vt_notifier_call,
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};
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/*
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* Called from printk.c when console=brl is given
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*/
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int braille_register_console(struct console *console, int index,
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char *console_options, char *braille_options)
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{
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int ret;
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if (!console_options)
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/* Only support VisioBraille for now */
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console_options = "57600o8";
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if (braille_co)
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return -ENODEV;
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if (console->setup) {
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ret = console->setup(console, console_options);
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if (ret != 0)
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return ret;
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}
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console->flags |= CON_ENABLED;
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console->index = index;
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braille_co = console;
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register_keyboard_notifier(&keyboard_notifier_block);
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register_vt_notifier(&vt_notifier_block);
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return 1;
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}
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int braille_unregister_console(struct console *console)
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{
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if (braille_co != console)
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return -EINVAL;
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unregister_keyboard_notifier(&keyboard_notifier_block);
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unregister_vt_notifier(&vt_notifier_block);
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braille_co = NULL;
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return 1;
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}
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