keyboard.c

This document describes how to complie keyboard and mouse driver. 键盘驱动

/*
 * linux/drivers/char/keyboard.c
 *
 * Written for linux by Johan Myreen as a translation from
 * the assembly version by Linus (with diacriticals added)
 *
 * Some additional features added by Christoph Niemann (ChN), March 1993
 *
 * Loadable keymaps by Risto Kankkunen, May 1993
 *
 * Diacriticals redone & other small changes, [e-mail], June 1993
 * Added decr/incr_console, dynamic keymaps, Unicode support,
 * dynamic function/string keys, led setting,  Sept 1994
 * `Sticky' modifier keys, 951006.
 *
 * 11-11-96: SAK should now work in the raw mode (Martin Mares)
 * 
 * Modified to provide 'generic' keyboard support by Hamish Macdonald
 * Merge with the m68k keyboard driver and split-off of the PC low-level
 * parts by Geert Uytterhoeven, May 1997
 *
 * 27-05-97: Added support for the Magic SysRq Key (Martin Mares)
 * 30-07-98: Dead keys redone, [e-mail].
 *
 * 04-04-1998: Added keyboard autorepeat support (some keyboards don't
 *   autorepeat, and some keyboard changers interfere with keyboard
 *   autorepeat settings).     - Russell King ([e-mail])
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/random.h>
#include <linux/init.h>

#include <asm/keyboard.h>
#include <asm/bitops.h>

#include <linux/kbd_kern.h>
#include <linux/kbd_diacr.h>
#include <linux/vt_kern.h>
#include <linux/kbd_ll.h>
#include <linux/sysrq.h>
#include <linux/pm.h>

#define SIZE(x) (sizeof(x)/sizeof((x)[0]))

#ifndef KBD_DEFMODE
#define KBD_DEFMODE ((1 << VC_REPEAT) | (1 << VC_META))
#endif

#ifndef KBD_DEFLEDS
/*
 * Some laptops take the 789uiojklm,. keys as number pad when NumLock
 * is on. This seems a good reason to start with NumLock off.
 */
#define KBD_DEFLEDS 0
#endif

#ifndef KBD_DEFLOCK
#define KBD_DEFLOCK 0
#endif

/*
 * Default autorepeat settings.
 *  DEFAULT_REPEAT_TIMEOUT is the timeout from the keypress to the first repeat
 *  DEFAULT_REPEAT_INTERVAL is the timeout between successive repeats
 */
#define DEFAULT_REPEAT_TIMEOUT	HZ*300/1000
#define DEFAULT_REPEAT_INTERVAL	HZ*30/1000

void (*kbd_ledfunc)(unsigned int led);
EXPORT_SYMBOL(handle_scancode);
EXPORT_SYMBOL(kbd_ledfunc);

extern void ctrl_alt_del(void);

DECLARE_WAIT_QUEUE_HEAD(keypress_wait);
struct console;

int keyboard_wait_for_keypress(struct console *co)
{
	sleep_on(&keypress_wait);
	return 0;
}

/*
 * global state includes the following, and various static variables
 * in this module: prev_scancode, shift_state, diacr, npadch, dead_key_next.
 * (last_console is now a global variable)
 */

/* shift state counters.. */
static unsigned char k_down[NR_SHIFT];
/* keyboard key bitmap */
static unsigned long key_down[256/BITS_PER_LONG];

static int dead_key_next;
/* 
 * In order to retrieve the shift_state (for the mouse server), either
 * the variable must be global, or a new procedure must be created to 
 * return the value. I chose the former way.
 */
int shift_state;
static int npadch = -1;			/* -1 or number assembled on pad */
static unsigned char diacr;
static char rep;			/* flag telling character repeat */
static int kbd_repeatkeycode= -1;
static int kbd_repeattimeout = DEFAULT_REPEAT_TIMEOUT;
static int kbd_repeatinterval= DEFAULT_REPEAT_INTERVAL;
struct kbd_struct kbd_table[MAX_NR_CONSOLES];
static struct tty_struct **ttytab;
static struct kbd_struct * kbd = kbd_table;
static struct tty_struct * tty;

static void kbd_processkeycode(unsigned char scancode, char up_flag, int autorepeat);
void compute_shiftstate(void);

typedef void (*k_hand)(unsigned char value, char up_flag);
typedef void (k_handfn)(unsigned char value, char up_flag);

static k_handfn
	do_self, do_fn, do_spec, do_pad, do_dead, do_cons, do_cur, do_shift,
	do_meta, do_ascii, do_lock, do_lowercase, do_slock, do_dead2,
	do_ignore;

static k_hand key_handler[16] = {
	do_self, do_fn, do_spec, do_pad, do_dead, do_cons, do_cur, do_shift,
	do_meta, do_ascii, do_lock, do_lowercase, do_slock, do_dead2,
	do_ignore, do_ignore
};

/* Key types processed even in raw modes */

#define TYPES_ALLOWED_IN_RAW_MODE ((1 << KT_SPEC) | (1 << KT_SHIFT))

typedef void (*void_fnp)(void);
typedef void (void_fn)(void);

static void_fn do_null, enter, show_ptregs, send_intr, lastcons, caps_toggle,
	num, hold, scroll_forw, scroll_back, boot_it, caps_on, compose,
	SAK, decr_console, incr_console, spawn_console, bare_num;

static void_fnp spec_fn_table[] = {
	do_null,	enter,		show_ptregs,	show_mem,
	show_state,	send_intr,	lastcons,	caps_toggle,
	num,		hold,		scroll_forw,	scroll_back,
	boot_it,	caps_on,	compose,	SAK,
	decr_console,	incr_console,	spawn_console,	bare_num
};

#define SPECIALS_ALLOWED_IN_RAW_MODE (1 << KVAL(K_SAK))

/* maximum values each key_handler can handle */
const int max_vals[] = {
	255, SIZE(func_table) - 1, SIZE(spec_fn_table) - 1, NR_PAD - 1,
	NR_DEAD - 1, 255, 3, NR_SHIFT - 1,
	255, NR_ASCII - 1, NR_LOCK - 1, 255,
	NR_LOCK - 1, 255
};

const int NR_TYPES = SIZE(max_vals);

/* N.B. drivers/macintosh/mac_keyb.c needs to call put_queue */
void put_queue(int);
static unsigned char handle_diacr(unsigned char);

/* kbd_pt_regs - set by keyboard_interrupt(), used by show_ptregs() */
struct pt_regs * kbd_pt_regs;

#ifdef CONFIG_MAGIC_SYSRQ
static int sysrq_pressed;
#endif

static struct pm_dev *pm_kbd;

/*
 * Many other routines do put_queue, but I think either
 * they produce ASCII, or they produce some user-assigned
 * string, and in both cases we might assume that it is
 * in utf-8 already.
 */
void to_utf8(ushort c)
{
    if (c < 0x80)
	put_queue(c);			/*  0*******  */
    else if (c < 0x800) {
	put_queue(0xc0 | (c >> 6)); 	/*  110***** 10******  */
	put_queue(0x80 | (c & 0x3f));
    } else {
	put_queue(0xe0 | (c >> 12)); 	/*  1110**** 10****** 10******  */
	put_queue(0x80 | ((c >> 6) & 0x3f));
	put_queue(0x80 | (c & 0x3f));
    }
    /* UTF-8 is defined for words of up to 31 bits,
       but we need only 16 bits here */
}

/*
 * Translation of escaped scancodes to keycodes.
 * This is now user-settable (for machines were it makes sense).
 */
int setkeycode(unsigned int scancode, unsigned int keycode)
{
	return kbd_setkeycode(scancode, keycode);
}

int getkeycode(unsigned int scancode)
{
	return kbd_getkeycode(scancode);
}

static void key_callback(unsigned long nr);

static struct timer_list key_autorepeat_timer =
{
	function: key_callback
};

void handle_scancode(unsigned char scancode, int down)
{
	unsigned char keycode;
	char up_flag = down ? 0 : 0200;
	char raw_mode;

	pm_access(pm_kbd);

	add_keyboard_randomness(scancode | up_flag);

	tty = ttytab? ttytab[fg_console]: NULL;
	if (tty && (!tty->driver_data)) {
		/*
		 * We touch the tty structure via the ttytab array
		 * without knowing whether or not tty is open, which
		 * is inherently dangerous.  We currently rely on that
		 * fact that console_open sets tty->driver_data when
		 * it opens it, and clears it when it closes it.
		 */
		tty = NULL;
	}
	kbd = kbd_table + fg_console;
	
		put_queue(scancode);
		/* we do not return yet, because we want to maintain
		   the key_down array, so that we have the correct
		   values when finishing RAW mode or when changing VT's */
	

	/*
	 *  Convert scancode to keycode
	 */
	/*	
	if (!kbd_translate(scancode, &keycode, raw_mode))
		goto out;
	*/

	/*
	 * At this point the variable `keycode' contains the keycode.
	 * Note: the keycode must not be 0 (++Geert: on m68k 0 is valid).
	 * We keep track of the up/down status of the key, and
	 * return the keycode if in MEDIUMRAW mode.
	 */
        /*
	kbd_processkeycode(keycode, up_flag, 0);
        */
out:
	do_poke_blanked_console = 1;
	schedule_console_callback();
}

static void
kbd_processkeycode(unsigned char keycode, char up_flag, int autorepeat)
{
	char raw_mode = (kbd->kbdmode == VC_RAW);

	if (up_flag) {
		rep = 0;
		if(!test_and_clear_bit(keycode, key_down))
		    up_flag = kbd_unexpected_up(keycode);
	} else {
		rep = test_and_set_bit(keycode, key_down);
		/* If the keyboard autorepeated for us, ignore it.
		 * We do our own autorepeat processing.
		 */
		if (rep && !autorepeat)
			return;
	}

	if (kbd_repeatkeycode == keycode || !up_flag || raw_mode) {
		kbd_repeatkeycode = -1;
		del_timer(&key_autorepeat_timer);
	}

#ifdef CONFIG_MAGIC_SYSRQ		/* Handle the SysRq Hack */
	if (keycode == SYSRQ_KEY) {
		sysrq_pressed = !up_flag;
		goto out;
	} else if (sysrq_pressed) {
		if (!up_flag) {
			handle_sysrq(kbd_sysrq_xlate[keycode], kbd_pt_regs, kbd, tty);
			goto out;
		}
	}
#endif

	/*
	 * Calculate the next time when we have to do some autorepeat
	 * processing.  Note that we do not do autorepeat processing
	 * while in raw mode but we do do autorepeat processing in
	 * medium raw mode.
	 */
	if (!up_flag && !raw_mode) {
		kbd_repeatkeycode = keycode;
		if (vc_kbd_mode(kbd, VC_REPEAT)) {
			if (rep)
				key_autorepeat_timer.expires = jiffies + kbd_repeatinterval;
			else
				key_autorepeat_timer.expires = jiffies + kbd_repeattimeout;
			add_timer(&key_autorepeat_timer);
		}
	}

	if (kbd->kbdmode == VC_MEDIUMRAW) {
		/* soon keycodes will require more than one byte */
		put_queue(keycode + up_flag);
		raw_mode = 1;	/* Most key classes will be ignored */
	}

	/*
	 * Small change in philosophy: earlier we defined repetition by
	 *	 rep = keycode == prev_keycode;
	 *	 prev_keycode = keycode;
	 * but now by the fact that the depressed key was down already.
	 * Does this ever make a difference? Yes.
	 */

	/*
	 *  Repeat a key only if the input buffers are empty or the
	 *  characters get echoed locally. This makes key repeat usable
	 *  with slow applications and under heavy loads.
	 */
	if (!rep ||
	    (vc_kbd_mode(kbd,VC_REPEAT) && tty &&
	     (L_ECHO(tty) || (tty->driver.chars_in_buffer(tty) == 0)))) {
		u_short keysym;
		u_char type;

		/* the XOR below used to be an OR */
		int shift_final = (shift_state | kbd->slockstate) ^
		    kbd->lockstate;
		ushort *key_map = key_maps[shift_final];

		if (key_map != NULL) {
			keysym = key_map[keycode];
			type = KTYP(keysym);

			if (type >= 0xf0) {
			    type -= 0xf0;
			    if (raw_mode && ! (TYPES_ALLOWED_IN_RAW_MODE & (1 << type)))
				goto out;
			    if (type == KT_LETTER) {
				type = KT_LATIN;
				if (vc_kbd_led(kbd, VC_CAPSLOCK)) {
				    key_map = key_maps[shift_final ^ (1<<KG_SHIFT)];
				    if (key_map)
				      keysym = key_map[keycode];
				}
			    }
			    (*key_handler[type])(keysym & 0xff, up_flag);
			    if (type != KT_SLOCK)
			      kbd->slockstate = 0;
			} else {
			    /* maybe only if (kbd->kbdmode == VC_UNICODE) ? */
			    if (!up_flag && !raw_mode)
			      to_utf8(keysym);
			}
		} else {
			/* maybe beep? */
			/* we have at least to update shift_state */
#if 1			/* how? two almost equivalent choices follow */
			compute_shiftstate();
			kbd->slockstate = 0; /* play it safe */
#else
			keysym = U(key_maps[0][keycode]);
			type = KTYP(keysym);
			if (type == KT_SHIFT)
			  (*key_handler[type])(keysym & 0xff, up_flag);
#endif
		}
	}
	rep = 0;
out:
}

/*
 * This clears the key down arrays when the keyboard is reset.  On
 * keyboard reset, this must be called before any keycodes are
 * received.
 */
void kbd_reset_kdown(void)
{
	int i;

	for (i = 0; i < NR_SHIFT; i++)
		k_down[i] = 0;
	for (i = 0; i < SIZE(key_down); i++)
		key_down[i] = 0;
	shift_state = 0;
}


void put_queue(int ch)
{
	wake_up(&keypress_wait);
	if (tty) {
		tty_insert_flip_char(tty, ch, 0);
		con_schedule_flip(tty);
	}
}

static void puts_queue(char *cp)
{
	wake_up(&keypress_wait);
	if (!tty)
		return;

	while (*cp) {
		tty_insert_flip_char(tty, *cp, 0);
		cp++;
	}
	con_schedule_flip(tty);
}

static void applkey(int key, char mode)
{
	static char buf[] = { 0x1b, 'O', 0x00, 0x00 };

	buf[1] = (mode ? 'O' : '[');
	buf[2] = key;
	puts_queue(buf);
}

static void enter(void)
{
	if (diacr) {
		put_queue(diacr);
		diacr = 0;
	}
	put_queue(13);
	if (vc_kbd_mode(kbd,VC_CRLF))
		put_queue(10);
}

static void caps_toggle(void)
{
	if (rep)
		return;
	chg_vc_kbd_led(kbd, VC_CAPSLOCK);
}

static void caps_on(void)
{
	if (rep)
		return;
	set_vc_kbd_led(kbd, VC_CAPSLOCK);
}

static void show_ptregs(void)
{
	if (kbd_pt_regs)
		show_regs(kbd_pt_regs);
}

static void hold(void)
{
	if (rep || !tty)
		return;

	/*
	 * Note: SCROLLOCK will be set (cleared) by stop_tty (start_tty);
	 * these routines are also activated by ^S/^Q.
	 * (And SCROLLOCK can also be set by the ioctl KDSKBLED.)
	 */
	if (tty->stopped)
		start_tty(tty);
	else
		stop_tty(tty);
}

static void num(void)
{
	if (vc_kbd_mode(kbd,VC_APPLIC))
		applkey('P', 1);
	else
		bare_num();
}

/*
 * Bind this to Shift-NumLock if you work in application keypad mode
 * but want to be able to change the NumLock flag.
 * Bind this to NumLock if you prefer that the NumLock key always
 * changes the NumLock flag.
 */
static void bare_num(void)
{
	if (!rep)
		chg_vc_kbd_led(kbd,VC_NUMLOCK);
}

static void lastcons(void)
{
	/* switch to the last used console, ChN */
	set_console(last_console);
}

static void decr_console(void)
{
	int i;
 
	for (i = fg_console-1; i != fg_console; i--) {
		if (i == -1)