Basic braille screen reader support
This adds a minimalistic braille screen reader support. This is meant to
be used by blind people e.g. on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.
[akpm@linux-foundation.org: fix exports]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/braille-console.txt b/Documentation/braille-console.txt
new file mode 100644
index 0000000..000b0fb
--- /dev/null
+++ b/Documentation/braille-console.txt
@@ -0,0 +1,34 @@
+ Linux Braille Console
+
+To get early boot messages on a braille device (before userspace screen
+readers can start), you first need to compile the support for the usual serial
+console (see serial-console.txt), and for braille device (in Device Drivers -
+Accessibility).
+
+Then you need to specify a console=brl, option on the kernel command line, the
+format is:
+
+ console=brl,serial_options...
+
+where serial_options... are the same as described in serial-console.txt
+
+So for instance you can use console=brl,ttyS0 if the braille device is connected
+to the first serial port, and console=brl,ttyS0,115200 to override the baud rate
+to 115200, etc.
+
+By default, the braille device will just show the last kernel message (console
+mode). To review previous messages, press the Insert key to switch to the VT
+review mode. In review mode, the arrow keys permit to browse in the VT content,
+page up/down keys go at the top/bottom of the screen, and the home key goes back
+to the cursor, hence providing very basic screen reviewing facility.
+
+Sound feedback can be obtained by adding the braille_console.sound=1 kernel
+parameter.
+
+For simplicity, only one braille console can be enabled, other uses of
+console=brl,... will be discarded. Also note that it does not interfere with
+the console selection mecanism described in serial-console.txt
+
+For now, only the VisioBraille device is supported.
+
+Samuel Thibault <samuel.thibault@ens-lyon.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 3ce193f..0ba0861 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -496,6 +496,11 @@
switching to the matching ttyS device later. The
options are the same as for ttyS, above.
+ If the device connected to the port is not a TTY but a braille
+ device, prepend "brl," before the device type, for instance
+ console=brl,ttyS0
+ For now, only VisioBraille is supported.
+
earlycon= [KNL] Output early console device and options.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c
index 09fcb50..cf6b5a7 100644
--- a/arch/powerpc/kernel/ppc_ksyms.c
+++ b/arch/powerpc/kernel/ppc_ksyms.c
@@ -133,9 +133,6 @@
EXPORT_SYMBOL(cuda_request);
EXPORT_SYMBOL(cuda_poll);
#endif /* CONFIG_ADB_CUDA */
-#ifdef CONFIG_VT
-EXPORT_SYMBOL(kd_mksound);
-#endif
EXPORT_SYMBOL(to_tm);
#ifdef CONFIG_PPC32
diff --git a/arch/ppc/kernel/ppc_ksyms.c b/arch/ppc/kernel/ppc_ksyms.c
index d9036ef..16ac11c 100644
--- a/arch/ppc/kernel/ppc_ksyms.c
+++ b/arch/ppc/kernel/ppc_ksyms.c
@@ -183,9 +183,6 @@
#if defined(CONFIG_BOOTX_TEXT)
EXPORT_SYMBOL(btext_update_display);
#endif
-#ifdef CONFIG_VT
-EXPORT_SYMBOL(kd_mksound);
-#endif
EXPORT_SYMBOL(to_tm);
EXPORT_SYMBOL(pm_power_off);
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 80f0ec9..59f33fa 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -84,6 +84,8 @@
source "drivers/leds/Kconfig"
+source "drivers/accessibility/Kconfig"
+
source "drivers/infiniband/Kconfig"
source "drivers/edac/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index e5e394a..f65deda 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -70,6 +70,7 @@
obj-$(CONFIG_PHONE) += telephony/
obj-$(CONFIG_MD) += md/
obj-$(CONFIG_BT) += bluetooth/
+obj-$(CONFIG_ACCESSIBILITY) += accessibility/
obj-$(CONFIG_ISDN) += isdn/
obj-$(CONFIG_EDAC) += edac/
obj-$(CONFIG_MCA) += mca/
diff --git a/drivers/accessibility/Kconfig b/drivers/accessibility/Kconfig
new file mode 100644
index 0000000..1264c4b
--- /dev/null
+++ b/drivers/accessibility/Kconfig
@@ -0,0 +1,23 @@
+menuconfig ACCESSIBILITY
+ bool "Accessibility support"
+ ---help---
+ Enable a submenu where accessibility items may be enabled.
+
+ If unsure, say N.
+
+if ACCESSIBILITY
+config A11Y_BRAILLE_CONSOLE
+ bool "Console on braille device"
+ depends on VT
+ depends on SERIAL_CORE_CONSOLE
+ ---help---
+ Enables console output on a braille device connected to a 8250
+ serial port. For now only the VisioBraille device is supported.
+
+ To actually enable it, you need to pass option
+ console=brl,ttyS0
+ to the kernel. Options are the same as for serial console.
+
+ If unsure, say N.
+
+endif # ACCESSIBILITY
diff --git a/drivers/accessibility/Makefile b/drivers/accessibility/Makefile
new file mode 100644
index 0000000..72b01a4
--- /dev/null
+++ b/drivers/accessibility/Makefile
@@ -0,0 +1 @@
+obj-y += braille/
diff --git a/drivers/accessibility/braille/Makefile b/drivers/accessibility/braille/Makefile
new file mode 100644
index 0000000..2e9f16c
--- /dev/null
+++ b/drivers/accessibility/braille/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille_console.o
diff --git a/drivers/accessibility/braille/braille_console.c b/drivers/accessibility/braille/braille_console.c
new file mode 100644
index 0000000..0a5f6b2
--- /dev/null
+++ b/drivers/accessibility/braille/braille_console.c
@@ -0,0 +1,397 @@
+/*
+ * 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;
+ return 0;
+}
+
+int braille_unregister_console(struct console *console)
+{
+ if (braille_co != console)
+ return -EINVAL;
+ braille_co = NULL;
+ return 0;
+}
+
+static int __init braille_init(void)
+{
+ register_keyboard_notifier(&keyboard_notifier_block);
+ register_vt_notifier(&vt_notifier_block);
+ return 0;
+}
+
+console_initcall(braille_init);
diff --git a/drivers/char/consolemap.c b/drivers/char/consolemap.c
index 6b104e4..4246b8e 100644
--- a/drivers/char/consolemap.c
+++ b/drivers/char/consolemap.c
@@ -277,6 +277,7 @@
return p->inverse_translations[m][glyph];
}
}
+EXPORT_SYMBOL_GPL(inverse_translate);
static void update_user_maps(void)
{
diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c
index d1c50b3..7f7e798 100644
--- a/drivers/char/keyboard.c
+++ b/drivers/char/keyboard.c
@@ -110,6 +110,7 @@
const int NR_TYPES = ARRAY_SIZE(max_vals);
struct kbd_struct kbd_table[MAX_NR_CONSOLES];
+EXPORT_SYMBOL_GPL(kbd_table);
static struct kbd_struct *kbd = kbd_table;
struct vt_spawn_console vt_spawn_con = {
@@ -260,6 +261,7 @@
} else
kd_nosound(0);
}
+EXPORT_SYMBOL(kd_mksound);
/*
* Setting the keyboard rate.
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 71cf203..e458b08 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -4004,6 +4004,7 @@
c |= 0x100;
return c;
}
+EXPORT_SYMBOL_GPL(screen_glyph);
/* used by vcs - note the word offset */
unsigned short *screen_pos(struct vc_data *vc, int w_offset, int viewed)
diff --git a/include/linux/console.h b/include/linux/console.h
index a5f88a6..a4f27fb 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -91,6 +91,7 @@
#define CON_ENABLED (4)
#define CON_BOOT (8)
#define CON_ANYTIME (16) /* Safe to call when cpu is offline */
+#define CON_BRL (32) /* Used for a braille device */
struct console {
char name[16];
@@ -121,6 +122,9 @@
extern void console_stop(struct console *);
extern void console_start(struct console *);
extern int is_console_locked(void);
+extern int braille_register_console(struct console *, int index,
+ char *console_options, char *braille_options);
+extern int braille_unregister_console(struct console *);
extern int console_suspend_enabled;
diff --git a/kernel/printk.c b/kernel/printk.c
index 0d23258..e61346f 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -111,6 +111,9 @@
char name[8]; /* Name of the driver */
int index; /* Minor dev. to use */
char *options; /* Options for the driver */
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ char *brl_options; /* Options for braille driver */
+#endif
};
#define MAX_CMDLINECONSOLES 8
@@ -808,15 +811,60 @@
#endif
+static int __add_preferred_console(char *name, int idx, char *options,
+ char *brl_options)
+{
+ struct console_cmdline *c;
+ int i;
+
+ /*
+ * See if this tty is not yet registered, and
+ * if we have a slot free.
+ */
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
+ if (strcmp(console_cmdline[i].name, name) == 0 &&
+ console_cmdline[i].index == idx) {
+ if (!brl_options)
+ selected_console = i;
+ return 0;
+ }
+ if (i == MAX_CMDLINECONSOLES)
+ return -E2BIG;
+ if (!brl_options)
+ selected_console = i;
+ c = &console_cmdline[i];
+ strlcpy(c->name, name, sizeof(c->name));
+ c->options = options;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ c->brl_options = brl_options;
+#endif
+ c->index = idx;
+ return 0;
+}
/*
* Set up a list of consoles. Called from init/main.c
*/
static int __init console_setup(char *str)
{
char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
- char *s, *options;
+ char *s, *options, *brl_options = NULL;
int idx;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (!memcmp(str, "brl,", 4)) {
+ brl_options = "";
+ str += 4;
+ } else if (!memcmp(str, "brl=", 4)) {
+ brl_options = str + 4;
+ str = strchr(brl_options, ',');
+ if (!str) {
+ printk(KERN_ERR "need port name after brl=\n");
+ return 1;
+ }
+ *(str++) = 0;
+ }
+#endif
+
/*
* Decode str into name, index, options.
*/
@@ -841,7 +889,7 @@
idx = simple_strtoul(s, NULL, 10);
*s = 0;
- add_preferred_console(buf, idx, options);
+ __add_preferred_console(buf, idx, options, brl_options);
return 1;
}
__setup("console=", console_setup);
@@ -861,28 +909,7 @@
*/
int add_preferred_console(char *name, int idx, char *options)
{
- struct console_cmdline *c;
- int i;
-
- /*
- * See if this tty is not yet registered, and
- * if we have a slot free.
- */
- for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
- if (strcmp(console_cmdline[i].name, name) == 0 &&
- console_cmdline[i].index == idx) {
- selected_console = i;
- return 0;
- }
- if (i == MAX_CMDLINECONSOLES)
- return -E2BIG;
- selected_console = i;
- c = &console_cmdline[i];
- memcpy(c->name, name, sizeof(c->name));
- c->name[sizeof(c->name) - 1] = 0;
- c->options = options;
- c->index = idx;
- return 0;
+ return __add_preferred_console(name, idx, options, NULL);
}
int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
@@ -1163,6 +1190,16 @@
continue;
if (console->index < 0)
console->index = console_cmdline[i].index;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console_cmdline[i].brl_options) {
+ console->flags |= CON_BRL;
+ braille_register_console(console,
+ console_cmdline[i].index,
+ console_cmdline[i].options,
+ console_cmdline[i].brl_options);
+ return;
+ }
+#endif
if (console->setup &&
console->setup(console, console_cmdline[i].options) != 0)
break;
@@ -1221,6 +1258,11 @@
struct console *a, *b;
int res = 1;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console->flags & CON_BRL)
+ return braille_unregister_console(console);
+#endif
+
acquire_console_sem();
if (console_drivers == console) {
console_drivers=console->next;