kernel/debug/kdb/kdb_keyboard.c

   1 /*
   2  * Kernel Debugger Architecture Dependent Console I/O handler
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.
   6  *
   7  * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
   8  * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
   9  */
  10
  11 #include <linux/kdb.h>
  12 #include <linux/keyboard.h>
  13 #include <linux/ctype.h>
  14 #include <linux/module.h>
  15 #include <linux/io.h>
  16
  17 /* Keyboard Controller Registers on normal PCs. */
  18
  19 #define KBD_STATUS_REG          0x64    /* Status register (R) */
  20 #define KBD_DATA_REG            0x60    /* Keyboard data register (R/W) */
  21
  22 /* Status Register Bits */
  23
  24 #define KBD_STAT_OBF            0x01    /* Keyboard output buffer full */
  25 #define KBD_STAT_MOUSE_OBF      0x20    /* Mouse output buffer full */
  26
  27 static int kbd_exists;
  28 static int kbd_last_ret;
  29
  30 /*
  31  * Check if the keyboard controller has a keypress for us.
  32  * Some parts (Enter Release, LED change) are still blocking polled here,
  33  * but hopefully they are all short.
  34  */
  35 int kdb_get_kbd_char(void)
  36 {
  37         int scancode, scanstatus;
  38         static int shift_lock;  /* CAPS LOCK state (0-off, 1-on) */
  39         static int shift_key;   /* Shift next keypress */
  40         static int ctrl_key;
  41         u_short keychar;
  42
  43         if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) ||
  44             (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
  45                 kbd_exists = 0;
  46                 return -1;
  47         }
  48         kbd_exists = 1;
  49
  50         if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
  51                 return -1;
  52
  53         /*
  54          * Fetch the scancode
  55          */
  56         scancode = inb(KBD_DATA_REG);
  57         scanstatus = inb(KBD_STATUS_REG);
  58
  59         /*
  60          * Ignore mouse events.
  61          */
  62         if (scanstatus & KBD_STAT_MOUSE_OBF)
  63                 return -1;
  64
  65         /*
  66          * Ignore release, trigger on make
  67          * (except for shift keys, where we want to
  68          *  keep the shift state so long as the key is
  69          *  held down).
  70          */
  71
  72         if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) {
  73                 /*
  74                  * Next key may use shift table
  75                  */
  76                 if ((scancode & 0x80) == 0)
  77                         shift_key = 1;
  78                 else
  79                         shift_key = 0;
  80                 return -1;
  81         }
  82
  83         if ((scancode&0x7f) == 0x1d) {
  84                 /*
  85                  * Left ctrl key
  86                  */
  87                 if ((scancode & 0x80) == 0)
  88                         ctrl_key = 1;
  89                 else
  90                         ctrl_key = 0;
  91                 return -1;
  92         }
  93
  94         if ((scancode & 0x80) != 0) {
  95                 if (scancode == 0x9c)
  96                         kbd_last_ret = 0;
  97                 return -1;
  98         }
  99
 100         scancode &= 0x7f;
 101
 102         /*
 103          * Translate scancode
 104          */
 105
 106         if (scancode == 0x3a) {
 107                 /*
 108                  * Toggle caps lock
 109                  */
 110                 shift_lock ^= 1;
 111
 112 #ifdef  KDB_BLINK_LED
 113                 kdb_toggleled(0x4);
 114 #endif
 115                 return -1;
 116         }
 117
 118         if (scancode == 0x0e) {
 119                 /*
 120                  * Backspace
 121                  */
 122                 return 8;
 123         }
 124
 125         /* Special Key */
 126         switch (scancode) {
 127         case 0xF: /* Tab */
 128                 return 9;
 129         case 0x53: /* Del */
 130                 return 4;
 131         case 0x47: /* Home */
 132                 return 1;
 133         case 0x4F: /* End */
 134                 return 5;
 135         case 0x4B: /* Left */
 136                 return 2;
 137         case 0x48: /* Up */
 138                 return 16;
 139         case 0x50: /* Down */
 140                 return 14;
 141         case 0x4D: /* Right */
 142                 return 6;
 143         }
 144
 145         if (scancode == 0xe0)
 146                 return -1;
 147
 148         /*
 149          * For Japanese 86/106 keyboards
 150          *      See comment in drivers/char/pc_keyb.c.
 151          *      - Masahiro Adegawa
 152          */
 153         if (scancode == 0x73)
 154                 scancode = 0x59;
 155         else if (scancode == 0x7d)
 156                 scancode = 0x7c;
 157
 158         if (!shift_lock && !shift_key && !ctrl_key) {
 159                 keychar = plain_map[scancode];
 160         } else if ((shift_lock || shift_key) && key_maps[1]) {
 161                 keychar = key_maps[1][scancode];
 162         } else if (ctrl_key && key_maps[4]) {
 163                 keychar = key_maps[4][scancode];
 164         } else {
 165                 keychar = 0x0020;
 166                 kdb_printf("Unknown state/scancode (%d)\n", scancode);
 167         }
 168         keychar &= 0x0fff;
 169         if (keychar == '\t')
 170                 keychar = ' ';
 171         switch (KTYP(keychar)) {
 172         case KT_LETTER:
 173         case KT_LATIN:
 174                 if (isprint(keychar))
 175                         break;          /* printable characters */
 176                 /* drop through */
 177         case KT_SPEC:
 178                 if (keychar == K_ENTER)
 179                         break;
 180                 /* drop through */
 181         default:
 182                 return -1;      /* ignore unprintables */
 183         }
 184
 185         if (scancode == 0x1c) {
 186                 kbd_last_ret = 1;
 187                 return 13;
 188         }
 189
 190         return keychar & 0xff;
 191 }
 192 EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
 193
 194 /*
 195  * Best effort cleanup of ENTER break codes on leaving KDB. Called on
 196  * exiting KDB, when we know we processed an ENTER or KP ENTER scan
 197  * code.
 198  */
 199 void kdb_kbd_cleanup_state(void)
 200 {
 201         int scancode, scanstatus;
 202
 203         /*
 204          * Nothing to clean up, since either
 205          * ENTER was never pressed, or has already
 206          * gotten cleaned up.
 207          */
 208         if (!kbd_last_ret)
 209                 return;
 210
 211         kbd_last_ret = 0;
 212         /*
 213          * Enter key. Need to absorb the break code here, lest it gets
 214          * leaked out if we exit KDB as the result of processing 'g'.
 215          *
 216          * This has several interesting implications:
 217          * + Need to handle KP ENTER, which has break code 0xe0 0x9c.
 218          * + Need to handle repeat ENTER and repeat KP ENTER. Repeats
 219          *   only get a break code at the end of the repeated
 220          *   sequence. This means we can't propagate the repeated key
 221          *   press, and must swallow it away.
 222          * + Need to handle possible PS/2 mouse input.
 223          * + Need to handle mashed keys.
 224          */
 225
 226         while (1) {
 227                 while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
 228                         cpu_relax();
 229
 230                 /*
 231                  * Fetch the scancode.
 232                  */
 233                 scancode = inb(KBD_DATA_REG);
 234                 scanstatus = inb(KBD_STATUS_REG);
 235
 236                 /*
 237                  * Skip mouse input.
 238                  */
 239                 if (scanstatus & KBD_STAT_MOUSE_OBF)
 240                         continue;
 241
 242                 /*
 243                  * If we see 0xe0, this is either a break code for KP
 244                  * ENTER, or a repeat make for KP ENTER. Either way,
 245                  * since the second byte is equivalent to an ENTER,
 246                  * skip the 0xe0 and try again.
 247                  *
 248                  * If we see 0x1c, this must be a repeat ENTER or KP
 249                  * ENTER (and we swallowed 0xe0 before). Try again.
 250                  *
 251                  * We can also see make and break codes for other keys
 252                  * mashed before or after pressing ENTER. Thus, if we
 253                  * see anything other than 0x9c, we have to try again.
 254                  *
 255                  * Note, if you held some key as ENTER was depressed,
 256                  * that break code would get leaked out.
 257                  */
 258                 if (scancode != 0x9c)
 259                         continue;
 260
 261                 return;
 262         }
 263 }