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Diffstat (limited to 'drivers/accessibility/braille/braille_console.c')
-rw-r--r--drivers/accessibility/braille/braille_console.c379
1 files changed, 379 insertions, 0 deletions
diff --git a/drivers/accessibility/braille/braille_console.c b/drivers/accessibility/braille/braille_console.c
new file mode 100644
index 0000000000..06b43b678d
--- /dev/null
+++ b/drivers/accessibility/braille/braille_console.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Minimalistic braille device kernel support.
+ *
+ * By default, shows console messages on the braille device.
+ * Pressing Insert switches to VC browsing.
+ *
+ * Copyright (C) Samuel Thibault <samuel.thibault@ens-lyon.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/console.h>
+#include <linux/notifier.h>
+
+#include <linux/selection.h>
+#include <linux/vt_kern.h>
+#include <linux/consolemap.h>
+
+#include <linux/keyboard.h>
+#include <linux/kbd_kern.h>
+#include <linux/input.h>
+
+MODULE_AUTHOR("samuel.thibault@ens-lyon.org");
+MODULE_DESCRIPTION("braille device");
+
+/*
+ * Braille device support part.
+ */
+
+/* Emit various sounds */
+static bool sound;
+module_param(sound, bool, 0);
+MODULE_PARM_DESC(sound, "emit sounds");
+
+static void beep(unsigned int freq)
+{
+ if (sound)
+ kd_mksound(freq, HZ/10);
+}
+
+/* mini console */
+#define WIDTH 40
+#define BRAILLE_KEY KEY_INSERT
+static u16 console_buf[WIDTH];
+static int console_cursor;
+
+/* mini view of VC */
+static int vc_x, vc_y, lastvc_x, lastvc_y;
+
+/* show console ? (or show VC) */
+static int console_show = 1;
+/* pending newline ? */
+static int console_newline = 1;
+static int lastVC = -1;
+
+static struct console *braille_co;
+
+/* Very VisioBraille-specific */
+static void braille_write(u16 *buf)
+{
+ static u16 lastwrite[WIDTH];
+ unsigned char data[1 + 1 + 2*WIDTH + 2 + 1], csum = 0, *c;
+ u16 out;
+ int i;
+
+ if (!braille_co)
+ return;
+
+ if (!memcmp(lastwrite, buf, WIDTH * sizeof(*buf)))
+ return;
+ memcpy(lastwrite, buf, WIDTH * sizeof(*buf));
+
+#define SOH 1
+#define STX 2
+#define ETX 2
+#define EOT 4
+#define ENQ 5
+ data[0] = STX;
+ data[1] = '>';
+ csum ^= '>';
+ c = &data[2];
+ for (i = 0; i < WIDTH; i++) {
+ out = buf[i];
+ if (out >= 0x100)
+ out = '?';
+ else if (out == 0x00)
+ out = ' ';
+ csum ^= out;
+ if (out <= 0x05) {
+ *c++ = SOH;
+ out |= 0x40;
+ }
+ *c++ = out;
+ }
+
+ if (csum <= 0x05) {
+ *c++ = SOH;
+ csum |= 0x40;
+ }
+ *c++ = csum;
+ *c++ = ETX;
+
+ braille_co->write(braille_co, data, c - data);
+}
+
+/* Follow the VC cursor*/
+static void vc_follow_cursor(struct vc_data *vc)
+{
+ vc_x = vc->state.x - (vc->state.x % WIDTH);
+ vc_y = vc->state.y;
+ lastvc_x = vc->state.x;
+ lastvc_y = vc->state.y;
+}
+
+/* Maybe the VC cursor moved, if so follow it */
+static void vc_maybe_cursor_moved(struct vc_data *vc)
+{
+ if (vc->state.x != lastvc_x || vc->state.y != lastvc_y)
+ vc_follow_cursor(vc);
+}
+
+/* Show portion of VC at vc_x, vc_y */
+static void vc_refresh(struct vc_data *vc)
+{
+ u16 buf[WIDTH];
+ int i;
+
+ for (i = 0; i < WIDTH; i++) {
+ u16 glyph = screen_glyph(vc,
+ 2 * (vc_x + i) + vc_y * vc->vc_size_row);
+ buf[i] = inverse_translate(vc, glyph, true);
+ }
+ braille_write(buf);
+}
+
+/*
+ * Link to keyboard
+ */
+
+static int keyboard_notifier_call(struct notifier_block *blk,
+ unsigned long code, void *_param)
+{
+ struct keyboard_notifier_param *param = _param;
+ struct vc_data *vc = param->vc;
+ int ret = NOTIFY_OK;
+
+ if (!param->down)
+ return ret;
+
+ switch (code) {
+ case KBD_KEYCODE:
+ if (console_show) {
+ if (param->value == BRAILLE_KEY) {
+ console_show = 0;
+ beep(880);
+ vc_maybe_cursor_moved(vc);
+ vc_refresh(vc);
+ ret = NOTIFY_STOP;
+ }
+ } else {
+ ret = NOTIFY_STOP;
+ switch (param->value) {
+ case KEY_INSERT:
+ beep(440);
+ console_show = 1;
+ lastVC = -1;
+ braille_write(console_buf);
+ break;
+ case KEY_LEFT:
+ if (vc_x > 0) {
+ vc_x -= WIDTH;
+ if (vc_x < 0)
+ vc_x = 0;
+ } else if (vc_y >= 1) {
+ beep(880);
+ vc_y--;
+ vc_x = vc->vc_cols-WIDTH;
+ } else
+ beep(220);
+ break;
+ case KEY_RIGHT:
+ if (vc_x + WIDTH < vc->vc_cols) {
+ vc_x += WIDTH;
+ } else if (vc_y + 1 < vc->vc_rows) {
+ beep(880);
+ vc_y++;
+ vc_x = 0;
+ } else
+ beep(220);
+ break;
+ case KEY_DOWN:
+ if (vc_y + 1 < vc->vc_rows)
+ vc_y++;
+ else
+ beep(220);
+ break;
+ case KEY_UP:
+ if (vc_y >= 1)
+ vc_y--;
+ else
+ beep(220);
+ break;
+ case KEY_HOME:
+ vc_follow_cursor(vc);
+ break;
+ case KEY_PAGEUP:
+ vc_x = 0;
+ vc_y = 0;
+ break;
+ case KEY_PAGEDOWN:
+ vc_x = 0;
+ vc_y = vc->vc_rows-1;
+ break;
+ default:
+ ret = NOTIFY_OK;
+ break;
+ }
+ if (ret == NOTIFY_STOP)
+ vc_refresh(vc);
+ }
+ break;
+ case KBD_POST_KEYSYM:
+ {
+ unsigned char type = KTYP(param->value) - 0xf0;
+
+ if (type == KT_SPEC) {
+ unsigned char val = KVAL(param->value);
+ int on_off = -1;
+
+ switch (val) {
+ case KVAL(K_CAPS):
+ on_off = vt_get_leds(fg_console, VC_CAPSLOCK);
+ break;
+ case KVAL(K_NUM):
+ on_off = vt_get_leds(fg_console, VC_NUMLOCK);
+ break;
+ case KVAL(K_HOLD):
+ on_off = vt_get_leds(fg_console, VC_SCROLLOCK);
+ break;
+ }
+ if (on_off == 1)
+ beep(880);
+ else if (on_off == 0)
+ beep(440);
+ }
+ }
+ break;
+ case KBD_UNBOUND_KEYCODE:
+ case KBD_UNICODE:
+ case KBD_KEYSYM:
+ /* Unused */
+ break;
+ }
+ return ret;
+}
+
+static struct notifier_block keyboard_notifier_block = {
+ .notifier_call = keyboard_notifier_call,
+};
+
+static int vt_notifier_call(struct notifier_block *blk,
+ unsigned long code, void *_param)
+{
+ struct vt_notifier_param *param = _param;
+ struct vc_data *vc = param->vc;
+
+ switch (code) {
+ case VT_ALLOCATE:
+ break;
+ case VT_DEALLOCATE:
+ break;
+ case VT_WRITE:
+ {
+ unsigned char c = param->c;
+
+ if (vc->vc_num != fg_console)
+ break;
+ switch (c) {
+ case '\b':
+ case 127:
+ if (console_cursor > 0) {
+ console_cursor--;
+ console_buf[console_cursor] = ' ';
+ }
+ break;
+ case '\n':
+ case '\v':
+ case '\f':
+ case '\r':
+ console_newline = 1;
+ break;
+ case '\t':
+ c = ' ';
+ fallthrough;
+ default:
+ if (c < 32)
+ /* Ignore other control sequences */
+ break;
+ if (console_newline) {
+ memset(console_buf, 0, sizeof(console_buf));
+ console_cursor = 0;
+ console_newline = 0;
+ }
+ if (console_cursor == WIDTH)
+ memmove(console_buf, &console_buf[1],
+ (WIDTH-1) * sizeof(*console_buf));
+ else
+ console_cursor++;
+ console_buf[console_cursor-1] = c;
+ break;
+ }
+ if (console_show)
+ braille_write(console_buf);
+ else {
+ vc_maybe_cursor_moved(vc);
+ vc_refresh(vc);
+ }
+ break;
+ }
+ case VT_UPDATE:
+ /* Maybe a VT switch, flush */
+ if (console_show) {
+ if (vc->vc_num != lastVC) {
+ lastVC = vc->vc_num;
+ memset(console_buf, 0, sizeof(console_buf));
+ console_cursor = 0;
+ braille_write(console_buf);
+ }
+ } else {
+ vc_maybe_cursor_moved(vc);
+ vc_refresh(vc);
+ }
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block vt_notifier_block = {
+ .notifier_call = vt_notifier_call,
+};
+
+/*
+ * Called from printk.c when console=brl is given
+ */
+
+int braille_register_console(struct console *console, int index,
+ char *console_options, char *braille_options)
+{
+ int ret;
+
+ if (!console_options)
+ /* Only support VisioBraille for now */
+ console_options = "57600o8";
+ if (braille_co)
+ return -ENODEV;
+ if (console->setup) {
+ ret = console->setup(console, console_options);
+ if (ret != 0)
+ return ret;
+ }
+ console->flags |= CON_ENABLED;
+ console->index = index;
+ braille_co = console;
+ register_keyboard_notifier(&keyboard_notifier_block);
+ register_vt_notifier(&vt_notifier_block);
+ return 1;
+}
+
+int braille_unregister_console(struct console *console)
+{
+ if (braille_co != console)
+ return -EINVAL;
+ unregister_keyboard_notifier(&keyboard_notifier_block);
+ unregister_vt_notifier(&vt_notifier_block);
+ braille_co = NULL;
+ return 1;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-09 07:56:24 +0000