path: root/chip/mec1322/system.c

/* Copyright (c) 2013 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.
 */

/* System module for Chrome EC : MEC1322 hardware specific implementation */

#include "clock.h"
#include "common.h"
#include "console.h"
#include "cpu.h"
#include "gpio.h"
#include "host_command.h"
#include "registers.h"
#include "system.h"
#include "task.h"
#include "timer.h"
#include "util.h"

/* Indices for hibernate data registers (RAM backed by VBAT) */
enum hibdata_index {
	HIBDATA_INDEX_SCRATCHPAD = 0,    /* General-purpose scratchpad */
	HIBDATA_INDEX_SAVED_RESET_FLAGS  /* Saved reset flags */
};

static int check_vcc1_por(void)
{
	/*
	 * WDT count resets on VCC1 POR. If we see WDT count = 0, we know
	 * POR has occurred, and we set WDT count to 1.
	 */
	if (MEC1322_EC_WDT_CNT == 0) {
		MEC1322_EC_WDT_CNT = 1;
		return 1;
	}

	return 0;
}

static void check_reset_cause(void)
{
	uint32_t status = MEC1322_VBAT_STS;
	uint32_t flags = 0;

	/* Clear the reset causes now that we've read them */
	MEC1322_VBAT_STS |= status;

	if (status & (1 << 7) || check_vcc1_por())
		flags |= RESET_FLAG_POWER_ON;

	flags |= MEC1322_VBAT_RAM(HIBDATA_INDEX_SAVED_RESET_FLAGS);
	MEC1322_VBAT_RAM(HIBDATA_INDEX_SAVED_RESET_FLAGS) = 0;

	if (status & (1 << 5) && !(flags & (RESET_FLAG_SOFT |
					    RESET_FLAG_HARD |
					    RESET_FLAG_HIBERNATE)))
		flags |= RESET_FLAG_WATCHDOG;

	system_set_reset_flags(flags);
}

void system_pre_init(void)
{
	/* Enable direct NVIC */
	MEC1322_EC_INT_CTRL |= 1;

	/* Disable ARM TRACE debug port */
	MEC1322_EC_TRACE_EN &= ~1;

	/* Deassert nSIO_RESET */
	MEC1322_PCR_PWR_RST_CTL &= ~(1 << 0);

	check_reset_cause();
}

void _system_reset(int flags, int wake_from_hibernate)
{
	uint32_t save_flags = 0;

	/* Disable interrupts to avoid task swaps during reboot */
	interrupt_disable();

	/* Save current reset reasons if necessary */
	if (flags & SYSTEM_RESET_PRESERVE_FLAGS)
		save_flags = system_get_reset_flags() | RESET_FLAG_PRESERVED;

	if (flags & SYSTEM_RESET_LEAVE_AP_OFF)
		save_flags |= RESET_FLAG_AP_OFF;

	if (wake_from_hibernate)
		save_flags |= RESET_FLAG_HIBERNATE;
	else if (flags & SYSTEM_RESET_HARD)
		save_flags |= RESET_FLAG_HARD;
	else
		save_flags |= RESET_FLAG_SOFT;

	MEC1322_VBAT_RAM(HIBDATA_INDEX_SAVED_RESET_FLAGS) = save_flags;

	/* Trigger watchdog in 1ms */
	MEC1322_WDG_LOAD = 1;
	MEC1322_WDG_CTL |= 1;

	/* Spin and wait for reboot; should never return */
	while (1)
		;
}

void system_reset(int flags)
{
	_system_reset(flags, 0);
}

const char *system_get_chip_vendor(void)
{
	return "smsc";
}

const char *system_get_chip_name(void)
{
	switch (MEC1322_CHIP_DEV_ID) {
	case 0x15:
		return "mec1322";
	default:
		return "unknown";
	}
}

static char to_hex(int x)
{
	if (x >= 0 && x <= 9)
		return '0' + x;
	return 'a' + x - 10;
}

const char *system_get_chip_revision(void)
{
	static char buf[3];
	uint8_t rev = MEC1322_CHIP_DEV_REV;

	buf[0] = to_hex(rev / 16);
	buf[1] = to_hex(rev & 0xf);
	buf[2] = '\0';
	return buf;
}

int system_get_vbnvcontext(uint8_t *block)
{
	return EC_ERROR_UNIMPLEMENTED;
}

int system_set_vbnvcontext(const uint8_t *block)
{
	return EC_ERROR_UNIMPLEMENTED;
}

int system_set_scratchpad(uint32_t value)
{
	MEC1322_VBAT_RAM(HIBDATA_INDEX_SCRATCHPAD) = value;
	return EC_SUCCESS;
}

uint32_t system_get_scratchpad(void)
{
	return MEC1322_VBAT_RAM(HIBDATA_INDEX_SCRATCHPAD);
}

static void system_unpower_gpio(void)
{
	int i, j, k;
	uint32_t val;
	int want_skip;

	const int pins[16][2] = {{0, 7}, {1, 7}, {2, 7}, {3, 6}, {4, 7}, {5, 7},
				 {6, 7}, {10, 7}, {11, 7}, {12, 7}, {13, 6},
				 {14, 7}, {15, 7}, {16, 5}, {20, 6}, {21, 1} };

	const int skip[5][2] = {{13, 1}, /* VCC1_nRST */
				{6, 3},  /* VCC_PWRGD */
				{12, 1}, /* nRESET_OUT */
				{14, 3}, /* RSMRST# */
				{20, 5}, /* Not exist */
	};

	for (i = 0; i < 16; ++i) {
		for (j = 0; j <= pins[i][1]; ++j) {
			want_skip = 0;
			for (k = 0; k < 5; ++k)
				if (skip[k][0] == pins[i][0] &&
				    skip[k][1] == j)
					want_skip = 1;
			if (want_skip)
				continue;

			/*
			 * GPIO Input, pull-high, interrupt disabled
			 * TODO(crosbug.com/p/25302): Unpower GPIO instead of
			 *                            setting them to be input.
			 */
			val = MEC1322_GPIO_CTL(pins[i][0], j);
			val &= ~((1 << 12) | (1 << 13));
			val &= ~(1 << 9);
			val = (val & ~(0xf << 4)) | (0x4 << 4);
			val = (val & ~0x3) | 0x1;
			MEC1322_GPIO_CTL(pins[i][0], j) = val;
		}
	}
}

void system_hibernate(uint32_t seconds, uint32_t microseconds)
{
	int i;

	cflush();

	/* Disable interrupts */
	interrupt_disable();
	for (i = 0; i <= 92; ++i) {
		task_disable_irq(i);
		task_clear_pending_irq(i);
	}

	for (i = 8; i <= 23; ++i)
		MEC1322_INT_DISABLE(i) = 0xffffffff;
	MEC1322_INT_BLK_DIS |= 0xffff00;

	/* Set processor clock to lowest, 1MHz */
	MEC1322_PCR_PROC_CLK_CTL = 48;

	/* Power down ADC VREF */
	MEC1322_EC_ADC_VREF_PD |= 1;

	/* Assert nSIO_RESET */
	MEC1322_PCR_PWR_RST_CTL |= 1;

	/* Disable UART */
	MEC1322_UART_ACT &= ~0x1;
	MEC1322_LPC_ACT &= ~0x1;

	/* Disable JTAG */
	MEC1322_EC_JTAG_EN &= ~1;

	/* Disable 32KHz clock */
	MEC1322_VBAT_CE &= ~0x2;

	/* Stop watchdog */
	MEC1322_WDG_CTL &= ~1;

	/* Stop timers */
	MEC1322_TMR32_CTL(0) &= ~1;
	MEC1322_TMR32_CTL(1) &= ~1;
	MEC1322_TMR16_CTL(0) &= ~1;

	/* Power down ADC */
	MEC1322_ADC_CTRL &= ~1;

	/* Disable blocks */
	MEC1322_PCR_CHIP_SLP_EN |= 0x3;
	MEC1322_PCR_EC_SLP_EN |= 0xe0700ff7;
	MEC1322_PCR_HOST_SLP_EN |= 0x5f003;
	MEC1322_PCR_EC_SLP_EN2 |= 0x1ffffff8;
	MEC1322_PCR_SYS_SLP_CTL = (MEC1322_PCR_SYS_SLP_CTL & ~0x7) | 0x2;
	MEC1322_PCR_SLOW_CLK_CTL &= 0xfffffc00;
	CPU_SCB_SYSCTRL |= 0x4;

	system_unpower_gpio();

#ifdef CONFIG_WAKE_PIN
	gpio_set_flags_by_mask(gpio_list[CONFIG_WAKE_PIN].port,
			       gpio_list[CONFIG_WAKE_PIN].mask,
			       gpio_list[CONFIG_WAKE_PIN].flags);
	gpio_enable_interrupt(CONFIG_WAKE_PIN);
	interrupt_enable();
	task_enable_irq(MEC1322_IRQ_GIRQ8);
	task_enable_irq(MEC1322_IRQ_GIRQ9);
	task_enable_irq(MEC1322_IRQ_GIRQ10);
	task_enable_irq(MEC1322_IRQ_GIRQ11);
	task_enable_irq(MEC1322_IRQ_GIRQ20);
#endif

	if (seconds || microseconds) {
		MEC1322_INT_BLK_EN |= 1 << 17;
		MEC1322_INT_ENABLE(17) |= 1 << 20;
		interrupt_enable();
		task_enable_irq(MEC1322_IRQ_HTIMER);
		if (seconds > 2) {
			ASSERT(seconds <= 0xffff / 8);
			MEC1322_HTIMER_CONTROL = 1;
			MEC1322_HTIMER_PRELOAD =
				(seconds * 8 + microseconds / 125000);
		} else {
			MEC1322_HTIMER_CONTROL = 0;
			MEC1322_HTIMER_PRELOAD =
				(seconds * 1000000 + microseconds) * 2 / 71;
		}
	}

	asm("wfi");

	/* We lost states of most modules, let's just reboot */
	_system_reset(0, 1);
}

void htimer_interrupt(void)
{
	/* Time to wake up */
	_system_reset(0, 1);
}
DECLARE_IRQ(MEC1322_IRQ_HTIMER, htimer_interrupt, 1);