/* Copyright (C) 2005  Thomas Petazzoni
 
    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 this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
    USA.
 */
 
 #include <sos/types.h>
 #include <sos/errno.h>
 #include <sos/assert.h>
 #include <hwcore/irq.h>
 #include <hwcore/ioports.h>
 
 #include "tty.h"
 
 /*
  * Keyboard ports and commands.
  * 
  * @see Ralf Brown's interrupt (and port) list   
  * http://www-2.cs.cmu.edu/~ralf/files.html      
  */
 
 #define KBD_DATA_PORT               0x60
 
 #define KBD_BREAKCODE_LIMIT         0x80
 #define KBD_EXTENDED_SCANCODE       0xE0
 
 #define KBD_IS_MAKECODE(c)          ((c) < KBD_BREAKCODE_LIMIT)
 #define KBD_IS_BREAKCODE(c)         ((c) >= KBD_BREAKCODE_LIMIT)
 #define KBD_BREAKCODE_2_MAKECODE(c) ((c) ^ KBD_BREAKCODE_LIMIT)
 
 #define KBD_LEFTSHIFT_SCANCODE      0x2a
 #define KBD_RIGHTSHIFT_SCANCODE     0x36
 
 typedef sos_ui8_t scancode_t;
 
 extern const char *kbd_regular_translate_table [];
 extern const char *kbd_shift_translate_table [];
 
 static const char **kbd_current_translate_table = kbd_regular_translate_table;
 static int is_ext = FALSE;
 
 static struct tty_device *tty;
 
 static void kbd_irq_handler (int irq_level)
 {
   scancode_t scancode;
   const char *key = NULL;
 
   scancode = inb (KBD_DATA_PORT);
 
   /* Mark that next interrupt wil give an extended scancode */
   if (scancode == KBD_EXTENDED_SCANCODE)
     {
       is_ext = TRUE;
     }
 
   /* Handle extended scancode */
   else if (is_ext)
     {
       is_ext = FALSE;
     }
 
   /* Normal scancode */
   else
     {
       /* Keypressed */
       if (KBD_IS_MAKECODE(scancode))
         {
           /* If shift, change translation table */
           if ((scancode == KBD_LEFTSHIFT_SCANCODE) ||
               (scancode == KBD_RIGHTSHIFT_SCANCODE))
             kbd_current_translate_table = kbd_shift_translate_table;
 
           /* If normal key, compute the result using the translation
              tables and the booleans */
           else if (kbd_current_translate_table[scancode])
             {
               key = kbd_current_translate_table[scancode];
             }
         }
 
       /* Key released */
       else
         {
           scancode_t makecode = KBD_BREAKCODE_2_MAKECODE(scancode);
 
           if ((makecode == KBD_LEFTSHIFT_SCANCODE) ||
               (makecode == KBD_RIGHTSHIFT_SCANCODE))
             kbd_current_translate_table = kbd_regular_translate_table;
         }
     }
 
   if (key)
     tty_add_chars (tty, key);
 }
 
 
 sos_ret_t sos_kbd_subsystem_setup(struct tty_device *t)
 {
   tty = t;
 
   sos_irq_set_routine (SOS_IRQ_KEYBOARD, kbd_irq_handler);
 
   return SOS_OK;
 }