/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/*
 * Keyboard scanner module for Chrome EC
 *
 * TODO: Finish cleaning up nomenclature (cols/rows/inputs/outputs),
 */

#include "atomic.h"
#include "board.h"
#include "console.h"
#include "gpio.h"
#include "host_command.h"
#include "keyboard.h"
#include "keyboard_scan.h"
#include "registers.h"
#include "system.h"
#include "task.h"
#include "timer.h"
#include "util.h"

/* Console output macros */
#define CPUTS(outstr) cputs(CC_KEYSCAN, outstr)
#define CPRINTF(format, args...) cprintf(CC_KEYSCAN, format, ## args)

/* used for select_column() */
enum COL_INDEX {
	COL_ASSERT_ALL = -2,
	COL_TRI_STATE_ALL = -1,
	/* 0 ~ 12 for the corresponding column */
};

#define POLLING_MODE_TIMEOUT 100000   /* 100 ms */
#define SCAN_LOOP_DELAY 10000         /*  10 ms */

/* 15:14, 12:8, 2 */
#define IRQ_MASK 0xdf04

static struct mutex scanning_enabled;

/* The keyboard state from the last read */
static uint8_t raw_state[KB_OUTPUTS];

/* Key masks for special boot keys */
#define MASK_INDEX_ESC     1
#define MASK_VALUE_ESC     0x02
#define MASK_INDEX_REFRESH 2
#define MASK_VALUE_REFRESH 0x04

/* Key masks and values for warm reboot combination */
#define MASK_INDEX_KEYR		3
#define MASK_VALUE_KEYR		0x80
#define MASK_INDEX_VOL_UP	4
#define MASK_VALUE_VOL_UP	0x01
#define MASK_INDEX_RIGHT_ALT	10
#define MASK_VALUE_RIGHT_ALT	0x01
#define MASK_INDEX_LEFT_ALT	10
#define MASK_VALUE_LEFT_ALT	0x40

struct kbc_gpio {
	int num;		/* logical row or column number */
	uint32_t port;
	int pin;
};

#if defined(BOARD_daisy) || defined(BOARD_snow) || defined(BOARD_spring)
static const uint32_t ports[] = { GPIO_B, GPIO_C, GPIO_D };
#else
#error "Need to specify GPIO ports used by keyboard"
#endif

/* Provide a default function in case the board doesn't have one */
void __board_keyboard_suppress_noise(void)
{
}

void board_keyboard_suppress_noise(void)
		__attribute__((weak, alias("__board_keyboard_suppress_noise")));

#define KB_FIFO_DEPTH		16	/* FIXME: this is pretty huge */
static uint32_t kb_fifo_start;		/* first entry */
static uint32_t kb_fifo_end;			/* last entry */
static uint32_t kb_fifo_entries;	/* number of existing entries */
static uint8_t kb_fifo[KB_FIFO_DEPTH][KB_OUTPUTS];

/* clear keyboard state variables */
void keyboard_clear_state(void)
{
	int i;

	CPRINTF("clearing keyboard fifo\n");
	kb_fifo_start = 0;
	kb_fifo_end = 0;
	kb_fifo_entries = 0;
	for (i = 0; i < KB_FIFO_DEPTH; i++)
		memset(kb_fifo[i], 0, KB_OUTPUTS);
}

/**
  * Add keyboard state into FIFO
  *
  * @return EC_SUCCESS if entry added, EC_ERROR_OVERFLOW if FIFO is full
  */
static int kb_fifo_add(uint8_t *buffp)
{
	int ret = EC_SUCCESS;

	if (kb_fifo_entries == KB_FIFO_DEPTH) {
		CPRINTF("%s: FIFO depth reached\n", __func__);
		ret = EC_ERROR_OVERFLOW;
		goto kb_fifo_push_done;
	}

	memcpy(kb_fifo[kb_fifo_end], buffp, KB_OUTPUTS);

	kb_fifo_end = (kb_fifo_end + 1) % KB_FIFO_DEPTH;

	atomic_add(&kb_fifo_entries, 1);

kb_fifo_push_done:
	return ret;
}

/**
  * Pop keyboard state from FIFO
  *
  * @return EC_SUCCESS if entry popped, EC_ERROR_UNKNOWN if FIFO is empty
  */
static int kb_fifo_remove(uint8_t *buffp)
{
	if (!kb_fifo_entries) {
		/* no entry remaining in FIFO : return last known state */
		int last = (kb_fifo_start + KB_FIFO_DEPTH - 1) % KB_FIFO_DEPTH;
		memcpy(buffp, kb_fifo[last], KB_OUTPUTS);

		/*
		 * Bail out without changing any FIFO indices and let the
		 * caller know something strange happened. The buffer will
		 * will contain the last known state of the keyboard.
		 */
		return EC_ERROR_UNKNOWN;
	}
	memcpy(buffp, kb_fifo[kb_fifo_start], KB_OUTPUTS);

	kb_fifo_start = (kb_fifo_start + 1) % KB_FIFO_DEPTH;

	atomic_sub(&kb_fifo_entries, 1);

	return EC_SUCCESS;
}

static void select_column(int col)
{
	int i, done = 0;

	for (i = 0; i < ARRAY_SIZE(ports); i++) {
		uint32_t bsrr = 0;
		int j;

		for (j = GPIO_KB_OUT00; j <= GPIO_KB_OUT12; j++) {
			if (gpio_list[j].port != ports[i])
				continue;

			if (col == COL_ASSERT_ALL) {
				/* drive low (clear output data) */
				bsrr |= gpio_list[j].mask << 16;
			} else if (col == COL_TRI_STATE_ALL) {
				/* put column in hi-Z state (set output data) */
				bsrr |= gpio_list[j].mask;
			} else {
				/* drive specified column low, others => hi-Z */
				if (j - GPIO_KB_OUT00 == col) {
					/* to avoid conflict, tri-state all
					 * columns first, then assert column */
					select_column(COL_TRI_STATE_ALL);
					bsrr |= gpio_list[j].mask << 16;
					done = 1;
					break;
				}
			}
		}

		if (bsrr)
			STM32_GPIO_BSRR_OFF(ports[i]) = bsrr;

		if (done)
			break;
	}
}


void wait_for_interrupt(void)
{
	uint32_t pr_before, pr_after;

	/* Assert all outputs would trigger un-wanted interrupts.
	 * Clear them before enable interrupt. */
	pr_before = STM32_EXTI_PR;
	select_column(COL_ASSERT_ALL);
	pr_after = STM32_EXTI_PR;
	STM32_EXTI_PR |= ((pr_after & ~pr_before) & IRQ_MASK);

	STM32_EXTI_IMR |= IRQ_MASK;	/* 1: unmask interrupt */
}


void enter_polling_mode(void)
{
	STM32_EXTI_IMR &= ~IRQ_MASK;	/* 0: mask interrupts */
	select_column(COL_TRI_STATE_ALL);
}

static int check_warm_reboot_keys(void)
{
	if (raw_state[MASK_INDEX_KEYR] == MASK_VALUE_KEYR &&
		  raw_state[MASK_INDEX_VOL_UP] == MASK_VALUE_VOL_UP &&
		  (raw_state[MASK_INDEX_RIGHT_ALT] == MASK_VALUE_RIGHT_ALT ||
		  raw_state[MASK_INDEX_LEFT_ALT] == MASK_VALUE_LEFT_ALT))
		return 1;

	return 0;
}

/* Returns 1 if any key is still pressed. 0 if no key is pressed. */
static int check_keys_changed(void)
{
	int c;
	uint8_t r;
	int change = 0;
	int num_press = 0;

	for (c = 0; c < KB_OUTPUTS; c++) {
		uint16_t tmp;

		/* Select column, then wait a bit for it to settle */
		select_column(c);
		udelay(50);

		r = 0;
		tmp = STM32_GPIO_IDR(C);
		/* KB_COL00:04 = PC8:12 */
		if (tmp & (1 << 8))
			r |= 1 << 0;
		if (tmp & (1 << 9))
			r |= 1 << 1;
		if (tmp & (1 << 10))
			r |= 1 << 2;
		if (tmp & (1 << 11))
			r |= 1 << 3;
		if (tmp & (1 << 12))
			r |= 1 << 4;
		/* KB_COL05:06 = PC14:15 */
		if (tmp & (1 << 14))
			r |= 1 << 5;
		if (tmp & (1 << 15))
			r |= 1 << 6;

		tmp = STM32_GPIO_IDR(D);
		/* KB_COL07 = PD2 */
		if (tmp & (1 << 2))
			r |= 1 << 7;

		/* Invert it so 0=not pressed, 1=pressed */
		r ^= 0xff;

#ifdef OR_WITH_CURRENT_STATE_FOR_TESTING
		/* KLUDGE - or current state in, so we can make sure
		 * all the lines are hooked up */
		r |= raw_state[c];
#endif

		/* Check for changes */
		if (r != raw_state[c]) {
			raw_state[c] = r;
			change = 1;
		}
	}
	select_column(COL_TRI_STATE_ALL);

	/* Count number of key pressed */
	for (c = 0; c < KB_OUTPUTS; c++) {
		if (raw_state[c])
			++num_press;
	}

	if (change) {
		board_keyboard_suppress_noise();

		CPRINTF("[%d keys pressed: ", num_press);
		for (c = 0; c < KB_OUTPUTS; c++) {
			if (raw_state[c])
				CPRINTF(" %02x", raw_state[c]);
			else
				CPUTS(" --");
		}
		CPUTS("]\n");

		if (num_press == 3) {
			if (check_warm_reboot_keys()) {
				keyboard_clear_state();
				system_warm_reboot();
				return 0;
			}
		}

		if (kb_fifo_add(raw_state) == EC_SUCCESS)
			board_interrupt_host(1);
		else
			CPRINTF("dropped keystroke\n");
	}

	return num_press ? 1 : 0;
}


/* Returns non-zero if the user has triggered a recovery reset by pushing
 * Power + Refresh + ESC. */
static int check_recovery_key(void)
{
	int c;

	/* check the recovery key only if we're booting due to a
	 * reset-pin-caused reset. */
	if (!(system_get_reset_flags() & RESET_FLAG_RESET_PIN))
		return 0;

	/* cold boot : Power + Refresh were pressed,
	 * check if ESC is also pressed for recovery. */
	if (!(raw_state[MASK_INDEX_ESC] & MASK_VALUE_ESC))
		return 0;

	/* Make sure only other allowed keys are pressed.  This protects
	 * against accidentally triggering the special key when a cat sits on
	 * your keyboard.  Currently, only the requested key and ESC are
	 * allowed. */
	for (c = 0; c < KB_OUTPUTS; c++) {
		if (raw_state[c] &&
		(c != MASK_INDEX_ESC || raw_state[c] != MASK_VALUE_ESC) &&
		(c != MASK_INDEX_REFRESH || raw_state[c] != MASK_VALUE_REFRESH))
			return 0;  /* Additional disallowed key pressed */
	}

	CPRINTF("Keyboard RECOVERY detected !\n");

	host_set_single_event(EC_HOST_EVENT_KEYBOARD_RECOVERY);

	return 1;
}


int keyboard_scan_init(void)
{
	/* Tri-state (put into Hi-Z) the outputs */
	select_column(COL_TRI_STATE_ALL);

	/* Initialize raw state */
	check_keys_changed();

	/* is recovery key pressed on cold startup ? */
	check_recovery_key();

	return EC_SUCCESS;
}


void keyboard_scan_task(void)
{
	int key_press_timer = 0;
	uint8_t keys_changed = 0;

	/* Enable interrupts for keyboard matrix inputs */
	gpio_enable_interrupt(GPIO_KB_IN00);
	gpio_enable_interrupt(GPIO_KB_IN01);
	gpio_enable_interrupt(GPIO_KB_IN02);
	gpio_enable_interrupt(GPIO_KB_IN03);
	gpio_enable_interrupt(GPIO_KB_IN04);
	gpio_enable_interrupt(GPIO_KB_IN05);
	gpio_enable_interrupt(GPIO_KB_IN06);
	gpio_enable_interrupt(GPIO_KB_IN07);

	while (1) {
		mutex_lock(&scanning_enabled);
		wait_for_interrupt();
		mutex_unlock(&scanning_enabled);

		task_wait_event(-1);

		enter_polling_mode();
		/* Busy polling keyboard state. */
		while (1) {
			/* sleep for debounce. */
			usleep(SCAN_LOOP_DELAY);
			/* Check for keys down */

			mutex_lock(&scanning_enabled);
			keys_changed = check_keys_changed();
			mutex_unlock(&scanning_enabled);

			if (keys_changed) {
				key_press_timer = 0;
			} else {
				if (++key_press_timer >=
				    (POLLING_MODE_TIMEOUT / SCAN_LOOP_DELAY)) {
					key_press_timer = 0;
					break;  /* exit the while loop */
				}
			}
		}
		/* TODO: (crosbug.com/p/7484) A race condition here.
		 *       If a key state is changed here (before interrupt is
		 *       enabled), it will be lost.
		 */
	}
}


void matrix_interrupt(enum gpio_signal signal)
{
	task_wake(TASK_ID_KEYSCAN);
}

int keyboard_has_char(void)
{
	/* TODO: needs to be implemented */
	return 0;
}

void keyboard_put_char(uint8_t chr, int send_irq)
{
	/* TODO: needs to be implemented */
}

int keyboard_scan_recovery_pressed(void)
{
	return host_get_events() &
	EC_HOST_EVENT_MASK(EC_HOST_EVENT_KEYBOARD_RECOVERY);
}

static int keyboard_get_scan(struct host_cmd_handler_args *args)
{
	kb_fifo_remove(args->response);
	if (!kb_fifo_entries)
		board_interrupt_host(0);

	args->response_size = KB_OUTPUTS;

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_MKBP_STATE,
		     keyboard_get_scan,
		     EC_VER_MASK(0));

static int keyboard_get_info(struct host_cmd_handler_args *args)
{
	struct ec_response_mkbp_info *r = args->response;

	r->rows = 8;
	r->cols = KB_OUTPUTS;
	r->switches = 0;

	args->response_size = sizeof(*r);

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_MKBP_INFO,
		     keyboard_get_info,
		     EC_VER_MASK(0));

void keyboard_enable_scanning(int enable)
{
	if (enable) {
		mutex_unlock(&scanning_enabled);
		task_wake(TASK_ID_KEYSCAN);
	} else {
		mutex_lock(&scanning_enabled);
		select_column(COL_TRI_STATE_ALL);
	}
}

static int command_keyboard_press(int argc, char **argv)
{
	int r, c, p;
	char *e;

	if (argc != 4)
		return EC_ERROR_PARAM_COUNT;

	c = strtoi(argv[1], &e, 0);
	if (*e || c < 0 || c >= KB_OUTPUTS)
		return EC_ERROR_PARAM1;

	r = strtoi(argv[2], &e, 0);
	if (*e || r < 0 || r >= 8)
		return EC_ERROR_PARAM2;

	p = strtoi(argv[3], &e, 0);
	if (*e || p < 0 || p > 1)
		return EC_ERROR_PARAM3;

	if (p)
		raw_state[c] |= (1 << r);
	else
		raw_state[c] &= ~(1 << r);

	if (kb_fifo_add(raw_state) == EC_SUCCESS)
		board_interrupt_host(1);
	else
		ccprintf("dropped keystroke\n");

	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(kbpress, command_keyboard_press,
			"[col] [row] [0 | 1]",
			"Simulate keypress",
			NULL);