Samuel Thibault, le Wed 06 Feb 2008 02:04:23 +0000, a écrit :
> Andrew Morton, le Tue 05 Feb 2008 16:58:53 -0800, a écrit :
> > On Tue, 5 Feb 2008 22:00:54 +0000
> > Samuel Thibault <[EMAIL PROTECTED]> wrote:
> > > + serial8250_console.write(braille_co, data, c - data);
> > 
> > hm.  Is it appropriate that this driver wire itself directly into
> > serial8250?
> > What if the screen reader is attached to some other sort of
> > uart, or a terminal server, or...
> 
> Indeed that's an issue.  For now, there is no clean way to attach to the
> early serial drivers, that's why I chose 8250,

In the patch below, I hook into kernel/printk.c's console= parser, which
now gives me attachment to any kind of console.




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.

Signed-off-by: Samuel Thibault <[EMAIL PROTECTED]>

diff -ur linux-2.6.24.1-orig/drivers/char/consolemap.c 
linux-2.6.24.1-perso/drivers/char/consolemap.c
--- linux-2.6.24.1-orig/drivers/char/consolemap.c       2008-01-25 
09:32:05.000000000 +0100
+++ linux-2.6.24.1-perso/drivers/char/consolemap.c      2008-02-03 
22:27:04.000000000 +0100
@@ -277,6 +277,7 @@
                        return p->inverse_translations[m][glyph];
        }
 }
+EXPORT_SYMBOL_GPL(inverse_translate);
 
 static void update_user_maps(void)
 {
diff -ur linux-2.6.24.1-orig/drivers/char/keyboard.c 
linux-2.6.24.1-perso/drivers/char/keyboard.c
--- linux-2.6.24.1-orig/drivers/char/keyboard.c 2008-01-25 09:32:06.000000000 
+0100
+++ linux-2.6.24.1-perso/drivers/char/keyboard.c        2008-02-04 
03:44:37.000000000 +0100
@@ -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_GPL(kd_mksound);
 
 /*
  * Setting the keyboard rate.
diff -ur linux-2.6.24.1-orig/drivers/char/vt.c 
linux-2.6.24.1-perso/drivers/char/vt.c
--- linux-2.6.24.1-orig/drivers/char/vt.c       2008-01-25 09:32:06.000000000 
+0100
+++ linux-2.6.24.1-perso/drivers/char/vt.c      2008-02-03 22:27:04.000000000 
+0100
@@ -3982,6 +3982,7 @@
                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 -ur linux-2.6.24.1-orig/drivers/Kconfig 
linux-2.6.24.1-perso/drivers/Kconfig
--- linux-2.6.24.1-orig/drivers/Kconfig 2008-01-25 09:32:04.000000000 +0100
+++ linux-2.6.24.1-perso/drivers/Kconfig        2008-02-20 21:52:54.000000000 
+0100
@@ -95,4 +95,6 @@
 source "drivers/uio/Kconfig"
 
 source "drivers/virtio/Kconfig"
+
+source "drivers/accessibility/Kconfig"
 endmenu
diff -ur linux-2.6.24.1-orig/drivers/Makefile 
linux-2.6.24.1-perso/drivers/Makefile
--- linux-2.6.24.1-orig/drivers/Makefile        2008-01-25 09:32:04.000000000 
+0100
+++ linux-2.6.24.1-perso/drivers/Makefile       2008-02-20 21:55:38.000000000 
+0100
@@ -5,6 +5,7 @@
 # Rewritten to use lists instead of if-statements.
 #
 
+obj-$(CONFIG_ACCESSIBILITY)    += accessibility/
 obj-$(CONFIG_PCI)              += pci/
 obj-$(CONFIG_PARISC)           += parisc/
 obj-$(CONFIG_RAPIDIO)          += rapidio/
diff -ur linux-2.6.24.1-orig/include/linux/console.h 
linux-2.6.24.1-perso/include/linux/console.h
--- linux-2.6.24.1-orig/include/linux/console.h 2008-01-25 09:32:44.000000000 
+0100
+++ linux-2.6.24.1-perso/include/linux/console.h        2008-02-21 
12:11:08.000000000 +0100
@@ -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 -ur linux-2.6.24.1-orig/kernel/printk.c 
linux-2.6.24.1-perso/kernel/printk.c
--- linux-2.6.24.1-orig/kernel/printk.c 2008-02-20 21:47:09.000000000 +0100
+++ linux-2.6.24.1-perso/kernel/printk.c        2008-02-21 12:09:06.000000000 
+0100
@@ -105,6 +105,7 @@
        char    name[8];                        /* Name of the driver       */
        int     index;                          /* Minor dev. to use        */
        char    *options;                       /* Options for the driver   */
+       char    *brl_options;                   /* Options for braille driver */
 };
 
 #define MAX_CMDLINECONSOLES 8
@@ -766,15 +767,59 @@
 
 #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];
+       memcpy(c->name, name, sizeof(c->name));
+       c->name[sizeof(c->name) - 1] = 0;
+       c->options = options;
+       c->brl_options = brl_options;
+       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.
         */
@@ -799,7 +844,7 @@
        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);
@@ -819,28 +864,7 @@
  */
 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)
@@ -1121,6 +1145,16 @@
                        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;
@@ -1179,6 +1213,11 @@
         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;
diff -urN linux-2.6.24.1-orig/drivers/accessibility/braille/braille_console.c 
linux-2.6.24.1-perso/drivers/accessibility/braille/braille_console.c
--- linux-2.6.24.1-orig/drivers/accessibility/braille/braille_console.c 
1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.24.1-perso/drivers/accessibility/braille/braille_console.c        
2008-02-21 12:27:41.000000000 +0100
@@ -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 <[EMAIL PROTECTED]>
+ *
+ * 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("[EMAIL PROTECTED]");
+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 -urN linux-2.6.24.1-orig/drivers/accessibility/Kconfig 
linux-2.6.24.1-perso/drivers/accessibility/Kconfig
--- linux-2.6.24.1-orig/drivers/accessibility/Kconfig   1970-01-01 
01:00:00.000000000 +0100
+++ linux-2.6.24.1-perso/drivers/accessibility/Kconfig  2008-02-20 
21:54:26.000000000 +0100
@@ -0,0 +1,22 @@
+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 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 -urN linux-2.6.24.1-orig/drivers/accessibility/Makefile 
linux-2.6.24.1-perso/drivers/accessibility/Makefile
--- linux-2.6.24.1-orig/drivers/accessibility/Makefile  1970-01-01 
01:00:00.000000000 +0100
+++ linux-2.6.24.1-perso/drivers/accessibility/Makefile 2008-02-04 
02:42:32.000000000 +0100
@@ -0,0 +1 @@
+obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)             += braille/braille_console.o
--
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