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linux/drivers/accessibility/braille/braille_console.c
Pascal Terjan c0c9209ddd braille_console: only register notifiers when the braille console is used 
Only register the braille driver VT and keyboard notifiers when the
braille console is used.  Avoids eating insert or backspace keys.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11242

Signed-off-by: Pascal Terjan <pterjan@mandriva.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02 15:53:13 -07:00

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/*
* 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>
*
* This program is free software ; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation ; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY ; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the program ; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/autoconf.h>
#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");
MODULE_LICENSE("GPL");
/*
* Braille device support part.
*/
/* Emit various sounds */
static int 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->vc_x - (vc->vc_x % WIDTH);
vc_y = vc->vc_y;
lastvc_x = vc->vc_x;
lastvc_y = vc->vc_y;
}
/* Maybe the VC cursor moved, if so follow it */
static void vc_maybe_cursor_moved(struct vc_data *vc)
{
if (vc->vc_x != lastvc_x || vc->vc_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, 1);
}
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 = vc_kbd_led(kbd_table + fg_console,
VC_CAPSLOCK);
break;
case KVAL(K_NUM):
on_off = vc_kbd_led(kbd_table + fg_console,
VC_NUMLOCK);
break;
case KVAL(K_HOLD):
on_off = vc_kbd_led(kbd_table + fg_console,
VC_SCROLLOCK);
break;
}
if (on_off == 1)
beep(880);
else if (on_off == 0)
beep(440);
}
}
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 0;
}
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 0;
}
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