#include "project.h"

#define KBCLK		(1UL << 0)
#define KBCLK_PORT	GPIOA
#define KBCLK_IRQ	NVIC_EXTI0_IRQ

#define KBDAT		(1UL << 1)
#define KBDAT_PORT	GPIOA

/*Cope with lost sync */
/*If we've had no bits for this long, it's definately the start of a new word,  72MHz units */
#define RESYNC_GAP 	(7200000) /* 100ms */

#define ATKBD_TIMEOUT	1000 /*how long to wait for the keyboard to respond to a command in ms */


typedef enum {
	STATE_START=0,
	STATE_BIT0,
	STATE_BIT1,
	STATE_BIT2,
	STATE_BIT3,
	STATE_BIT4,
	STATE_BIT5,
	STATE_BIT6,
	STATE_BIT7,
	STATE_PARITY,
	STATE_STOP,
} atkbd_state;


#define ATKBD_CMD_SETLEDS       0xed
#define ATKBD_CMD_GSCANSET      0xf0
#define ATKBD_CMD_SSCANSET      0xf0
#define ATKBD_CMD_GETID         0xf2
#define ATKBD_CMD_SETREP        0xf3
#define ATKBD_CMD_ENABLE        0xf4
#define ATKBD_CMD_RESET_DIS     0xf5
#define ATKBD_CMD_RESET_DEF     0xf6
#define ATKBD_CMD_SETALL_MB     0xf8
#define ATKBD_CMD_SETALL_MBR    0xfa 
#define ATKBD_CMD_RESET_BAT     0xff
#define ATKBD_CMD_RESEND        0xfe
#define ATKBD_CMD_EX_ENABLE     0xea
#define ATKBD_CMD_EX_SETLEDS    0xeb
#define ATKBD_CMD_OK_GETID      0xe8

#define ATKBD_RET_ECHO          0xee
#define ATKBD_RET_ACK           0xfa
#define ATKBD_RET_NAK           0xfe
#define ATKBD_RET_BAT           0xaa
#define ATKBD_RET_EMUL0         0xe0
#define ATKBD_RET_EMUL1         0xe1
#define ATKBD_RET_RELEASE       0xf0
#define ATKBD_RET_HANJA         0xf1
#define ATKBD_RET_HANGEUL       0xf2
#define ATKBD_RET_ERR           0xff

#define ATKBD_KEY_UNKNOWN       0
#define ATKBD_KEY_NULL          255


static int atkbd_ack;
static int atkbd_nack;
static int atkbd_bat;
static int atkbd_echo;



static uint32_t cycle_diff(uint32_t a,uint32_t b)
{
return b-a;
}


static void atkbd_dispatch(int emul,int key,int updown)
{

printf("KEY> %x %x %x\r\n",emul,key,updown);


}

static void atkbd_data_dispatch(uint8_t byte)
{
static int release;
static int emul;

printf("ATKBD < 0x%02x\r\n",byte);

switch (byte) {
case ATKBD_RET_ACK:
	atkbd_ack++;
	break;
case ATKBD_RET_NAK:
	atkbd_nack++;
	break;
case ATKBD_RET_BAT:
	atkbd_bat++;
	break;
case ATKBD_RET_ECHO:
	atkbd_echo++;
	break;
case ATKBD_RET_ERR:
case ATKBD_KEY_UNKNOWN:
case ATKBD_RET_HANJA: /*Don't handle japanese or korean for the moment*/
case ATKBD_RET_HANGEUL: /*Don't handle japanese or korean for the moment*/
	/*All these need no action */
	break;
case ATKBD_RET_EMUL0:
	emul=1;
	break;
case ATKBD_RET_EMUL1:
	emul=2;
	break;
case ATKBD_RET_RELEASE:
	release=1;
	break;
default:
	atkbd_dispatch(emul,byte,release);
	emul=0;
	release=0;
}
	
}


void exti0_isr(void)
{
 static uint32_t last_interrupt=0;
 static atkbd_state state=STATE_START;
 static uint8_t atkbd_byte;
 static int parity;

 uint32_t now,diff;
 int d;

 d=!!GET(KBDAT);

 exti_reset_request(KBCLK);

 now=dwt_read_cycle_counter();
 diff=cycle_diff(last_interrupt,now);
 last_interrupt=now;


 if (diff>RESYNC_GAP) state=STATE_START;


 switch (state) {
	case STATE_START:
		atkbd_byte=0;
		parity=0;
		if (!d) state++;
		break;
	case STATE_BIT0:
	case STATE_BIT1:
	case STATE_BIT2:
	case STATE_BIT3:
	case STATE_BIT4:
	case STATE_BIT5:
	case STATE_BIT6:
	case STATE_BIT7:
		atkbd_byte|=d<<(state-STATE_BIT0);
		/* fall through*/
	case STATE_PARITY:
		parity ^= d;
		state++;
		break;
	case STATE_STOP:
		if (d && parity) atkbd_data_dispatch(atkbd_byte);
		state=STATE_START;
		break;
	}
}



void atkbd_set(int clk,int dat)
{
if (clk) {
	MAP_INPUT_PU(KBCLK);
} else {
	CLEAR(KBCLK);
	MAP_OUTPUT_PP(KBCLK);
}


if (dat) {
	MAP_INPUT_PU(KBDAT);
} else {
	CLEAR(KBDAT);
	MAP_OUTPUT_PP(KBDAT);
}

}


int atkbd_send(uint8_t d)
{
uint32_t then=ticks;
int parity=1;
uint32_t c;


nvic_disable_irq(KBCLK_IRQ);

#define PS2_CLOCK_SEIZE_DELAY 200
#define PS2_BIT_DELAY	10

atkbd_set(0,1);
delay_us(PS2_CLOCK_SEIZE_DELAY);
atkbd_set(0,0);
delay_us(PS2_BIT_DELAY);
atkbd_set(1,0);
delay_us(PS2_BIT_DELAY);

for (c=1;c<0x100;c<<=1)  {
while (GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
atkbd_set(1,c&d);
parity^=!!(c&d);
while (!GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
}
while (GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
atkbd_set(1,parity);
while (!GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;

while (GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
while (!GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;

atkbd_set(1,1);
while (GET(KBDAT)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
while (GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;



while (!GET(KBDAT)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
while (!GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;

exti_reset_request(KBCLK);
nvic_enable_irq(KBCLK_IRQ);

printf("ATKBD > 0x%02x\r\n",d);

return 0;

err:
atkbd_set(1,1);
while (!GET(KBDAT)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;
while (!GET(KBCLK)) if (timed_out(then,ATKBD_TIMEOUT)) goto err;

exti_reset_request(KBCLK);
nvic_enable_irq(KBCLK_IRQ);

printf("ATKBD >! 0x%02x\r\n",d);
return -1;
}

static int atkbd_reset(void)
{
uint32_t then=ticks;
atkbd_bat=0;
atkbd_send(ATKBD_CMD_RESET_BAT);
while (!atkbd_bat) if (timed_out(then,ATKBD_TIMEOUT)) return -1;

then=ticks;
atkbd_ack=0;
atkbd_send(ATKBD_CMD_SETALL_MBR);
while (!atkbd_ack) if (timed_out(then,ATKBD_TIMEOUT)) return -1;


return 0;
}

int atkbd_request_echo(void)
{
uint32_t then=ticks;
atkbd_ack=0;
atkbd_send(ATKBD_CMD_ECHO);
while (!atkbd_echo) if (timed_out(then,ATKBD_TIMEOUT)) return -1;

return 0;
}


int atkbd_set_leds(uint8_t leds)
{
uint32_t then=ticks;
atkbd_ack=0;
atkbd_send(ATKBD_CMD_SETLEDS);
while (!atkbd_ack) if (timed_out(then,ATKBD_TIMEOUT)) return -1;

then=ticks;
atkbd_ack=0;
atkbd_send(leds);
while (!atkbd_ack) if (timed_out(then,ATKBD_TIMEOUT)) return -1;

return 0;
}


void atkbd_init(void)
{
atkbd_set(1,1);
delay_ms(200);

nvic_enable_irq(NVIC_EXTI0_IRQ);


exti_select_source(KBCLK, KBCLK_PORT);
exti_set_trigger(KBCLK, EXTI_TRIGGER_FALLING);
exti_enable_request(KBCLK);

exti_reset_request(KBCLK);
nvic_enable_irq(KBCLK_IRQ);


atkbd_reset();
atkbd_request_echo();
atkbd_set_leds(0x07);


}