path: root/chip/lm4/pwm.c

/* 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.
 */

/* PWM control module for Chrome EC */

#include "common.h"
#include "console.h"
#include "gpio.h"
#include "hooks.h"
#include "host_command.h"
#include "pwm.h"
#include "registers.h"
#include "system.h"
#include "task.h"
#include "thermal.h"
#include "timer.h"
#include "util.h"

/* Maximum RPM for fan controller */
#define MAX_RPM 0x1fff
/* Max PWM for fan controller */
#define MAX_PWM 0x1ff
/*
 * Scaling factor for requested/actual RPM for CPU fan.  We need this because
 * the fan controller on Blizzard filters tach pulses that are less than 64
 * 15625Hz ticks apart, which works out to ~7000rpm on an unscaled fan.  By
 * telling the controller we actually have twice as many edges per revolution,
 * the controller can handle fans that actually go twice as fast.  See
 * crosbug.com/p/7718.
 */
#define CPU_FAN_SCALE 2


#define PWM_SYSJUMP_TAG 0x504d  /* "PM" */
#define PWM_HOOK_VERSION 1
/* the previous pwm state before reboot_ec. */
struct pwm_state {
	uint16_t fan_rpm;
	uint8_t fan_en;
	uint8_t kblight_en;
	uint8_t kblight_percent;
	char pad; /* Pad to multiple of 4 bytes. */
};


/* Configures the GPIOs for the fan module. */
static void configure_gpios(void)
{
	/* PK6 alternate function 1 = channel 1 PWM */
	gpio_set_alternate_function(LM4_GPIO_K, 0x40, 1);
	/* PM6:7 alternate function 1 = channel 0 PWM/tach */
	gpio_set_alternate_function(LM4_GPIO_M, 0xc0, 1);
}

int pwm_enable_fan(int enable)
{
	if (enable)
		LM4_FAN_FANCTL |= (1 << FAN_CH_CPU);
	else
		LM4_FAN_FANCTL &= ~(1 << FAN_CH_CPU);

	return EC_SUCCESS;
}

int pwm_get_fan_enabled(void)
{
	return (LM4_FAN_FANCTL & (1 << FAN_CH_CPU)) ? 1 : 0;
}

int pwm_get_fan_rpm(void)
{
	return (LM4_FAN_FANCST(FAN_CH_CPU) & MAX_RPM) * CPU_FAN_SCALE;
}

int pwm_get_fan_target_rpm(void)
{
	return (LM4_FAN_FANCMD(FAN_CH_CPU) & MAX_RPM) * CPU_FAN_SCALE;
}

int pwm_set_fan_target_rpm(int rpm)
{
	/* Apply fan scaling */
	if (rpm > 0)
		rpm /= CPU_FAN_SCALE;

	/* Treat out-of-range requests as requests for maximum fan speed */
	if (rpm < 0 || rpm > MAX_RPM)
		rpm = MAX_RPM;

	LM4_FAN_FANCMD(FAN_CH_CPU) = rpm;
	return EC_SUCCESS;
}

int pwm_enable_keyboard_backlight(int enable)
{
	if (enable)
		LM4_FAN_FANCTL |= (1 << FAN_CH_KBLIGHT);
	else
		LM4_FAN_FANCTL &= ~(1 << FAN_CH_KBLIGHT);

	return EC_SUCCESS;
}

int pwm_get_keyboard_backlight_enabled(void)
{
	return (LM4_FAN_FANCTL & (1 << FAN_CH_KBLIGHT)) ? 1 : 0;
}

int pwm_get_keyboard_backlight(void)
{
	return ((LM4_FAN_FANCMD(FAN_CH_KBLIGHT) >> 16) * 100 +
		MAX_PWM / 2) / MAX_PWM;
}

int pwm_set_keyboard_backlight(int percent)
{
	if (percent < 0)
		percent = 0;
	else if (percent > 100)
		percent = 100;

	LM4_FAN_FANCMD(FAN_CH_KBLIGHT) = ((percent * MAX_PWM + 50) / 100) << 16;
	return EC_SUCCESS;
}

/**
 * Return non-zero if fan is enabled but stalled
 */
static int fan_is_stalled(void)
{
	/* Must be enabled with non-zero target to stall */
	if (!pwm_get_fan_enabled() || pwm_get_fan_target_rpm() == 0)
		return 0;

	/* Check for stall condition */
	return (((LM4_FAN_FANSTS >> (2 * FAN_CH_CPU)) & 0x03) == 0) ? 1 : 0;
}

void pwm_task(void)
{
	uint16_t *mapped = (uint16_t *)host_get_memmap(EC_MEMMAP_FAN);

	while (1) {
		if (fan_is_stalled()) {
			mapped[0] = EC_FAN_SPEED_STALLED;
			/*
			 * Issue warning.  As we have thermal shutdown
			 * protection, issuing warning here should be enough.
			 */
			host_set_single_event(EC_HOST_EVENT_THERMAL);
			cprintf(CC_PWM, "[%T Fan stalled!]\n");
		} else
			mapped[0] = pwm_get_fan_rpm();

		/* Update about once a second */
		usleep(1000000);
	}
}


/*****************************************************************************/
/* Console commands */

static int command_fan_info(int argc, char **argv)
{
	ccprintf("Actual: %4d rpm\n", pwm_get_fan_rpm());
	ccprintf("Target: %4d rpm\n", pwm_get_fan_target_rpm());
	ccprintf("Duty:   %d%%\n",
		 ((LM4_FAN_FANCMD(FAN_CH_CPU) >> 16)) * 100 / MAX_PWM);
	ccprintf("Status: %d\n",
		 (LM4_FAN_FANSTS >> (2 * FAN_CH_CPU)) & 0x03);
	ccprintf("Enable: %s\n",
		 pwm_get_fan_enabled() ? "yes" : "no");
	ccprintf("Power:  %s\n",
		 gpio_get_level(GPIO_PGOOD_5VALW) ? "yes" : "no");

	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(faninfo, command_fan_info,
			NULL,
			"Print fan info",
			NULL);

static int command_fan_set(int argc, char **argv)
{
	int rpm = 0;
	char *e;

	if (argc < 2)
		return EC_ERROR_PARAM_COUNT;

	rpm = strtoi(argv[1], &e, 0);
	if (*e)
		return EC_ERROR_PARAM1;

        /* Move the fan to automatic control */
        if (LM4_FAN_FANCH(FAN_CH_CPU) & 0x0001) {
		pwm_enable_fan(0);
		LM4_FAN_FANCH(FAN_CH_CPU) &= ~0x0001;
        }
	/* Always enable the fan */
	pwm_enable_fan(1);

#ifdef CONFIG_TASK_THERMAL
	/* Disable thermal engine automatic fan control. */
	thermal_control_fan(0);
#endif

	return pwm_set_fan_target_rpm(rpm);
}
DECLARE_CONSOLE_COMMAND(fanset, command_fan_set,
			"rpm",
			"Set fan speed",
			NULL);

int pwm_set_fan_duty(int percent)
{
	int pwm;

	if (percent < 0)
		percent = 0;
	else if (percent > 100)
		percent = 100;

	pwm = (MAX_PWM * percent) / 100;

        /* Move the fan to manual control */
        if (!(LM4_FAN_FANCH(FAN_CH_CPU) & 0x0001)) {
		pwm_enable_fan(0);
		LM4_FAN_FANCH(FAN_CH_CPU) |= 0x0001;
        }
	/* Always enable the fan */
	pwm_enable_fan(1);

#ifdef CONFIG_TASK_THERMAL
	/* Disable thermal engine automatic fan control. */
	thermal_control_fan(0);
#endif

        /* Set the duty cycle */
	LM4_FAN_FANCMD(FAN_CH_CPU) = pwm << 16;

	return EC_SUCCESS;
}

static int ec_command_fan_duty(int argc, char **argv)
{
	int percent = 0;
	char *e;

	if (argc < 2)
		return EC_ERROR_PARAM_COUNT;

	percent = strtoi(argv[1], &e, 0);
	if (*e)
		return EC_ERROR_PARAM1;

	ccprintf("Setting fan duty cycle to %d%%\n", percent);
	pwm_set_fan_duty(percent);

	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(fanduty, ec_command_fan_duty,
			"percent",
			"Set fan duty cycle",
			NULL);

static int command_kblight(int argc, char **argv)
{
	int rv = EC_SUCCESS;

	if (argc >= 2) {
		char *e;
		int i = strtoi(argv[1], &e, 0);
		if (*e)
			return EC_ERROR_PARAM1;
		rv = pwm_set_keyboard_backlight(i);
	}

	ccprintf("Keyboard backlight: %d%%\n", pwm_get_keyboard_backlight());
	return rv;
}
DECLARE_CONSOLE_COMMAND(kblight, command_kblight,
			"percent",
			"Set keyboard backlight",
			NULL);

/*****************************************************************************/
/* Initialization */

static int pwm_init(void)
{
	volatile uint32_t scratch  __attribute__((unused));
	const struct pwm_state *prev;
	uint16_t *mapped;
	int version, size;
	int i;

	/* Enable the fan module and delay a few clocks */
	LM4_SYSTEM_RCGCFAN = 1;
	scratch = LM4_SYSTEM_RCGCFAN;

	/* Configure GPIOs */
	configure_gpios();

	/* Disable all fans */
	LM4_FAN_FANCTL = 0;

	/*
	 * Configure CPU fan:
	 * 0x8000 = bit 15     = auto-restart
	 * 0x0000 = bit 14     = slow acceleration
	 * 0x0000 = bits 13:11 = no hysteresis
	 * 0x0000 = bits 10:8  = start period (2<<0) edges
	 * 0x0000 = bits 7:6   = no fast start
	 * 0x0020 = bits 5:4   = average 4 edges when calculating RPM
	 * 0x000c = bits 3:2   = 8 pulses per revolution
	 *                       (see note at top of file)
	 * 0x0000 = bit 0      = automatic control
	 */
	LM4_FAN_FANCH(FAN_CH_CPU) = 0x802c;

	/*
	 * Configure keyboard backlight:
	 * 0x0000 = bit 15     = auto-restart
	 * 0x0000 = bit 14     = slow acceleration
	 * 0x0000 = bits 13:11 = no hysteresis
	 * 0x0000 = bits 10:8  = start period (2<<0) edges
	 * 0x0000 = bits 7:6   = no fast start
	 * 0x0000 = bits 5:4   = average 4 edges when calculating RPM
	 * 0x0000 = bits 3:2   = 4 pulses per revolution
	 * 0x0001 = bit 0      = manual control
	 */
	LM4_FAN_FANCH(FAN_CH_KBLIGHT) = 0x0001;

	prev = (const struct pwm_state *)system_get_jump_tag(PWM_SYSJUMP_TAG,
							     &version, &size);
	if (prev && version == PWM_HOOK_VERSION && size == sizeof(*prev)) {
		/* Restore previous state. */
		pwm_enable_fan(prev->fan_en);
		pwm_set_fan_target_rpm(prev->fan_rpm);
		pwm_enable_keyboard_backlight(prev->kblight_en);
		pwm_set_keyboard_backlight(prev->kblight_percent);
	}
	else {
		/* Set initial fan speed to maximum, backlight off */
		pwm_set_fan_target_rpm(-1);
		pwm_set_keyboard_backlight(0);

		/*
		 * Enable keyboard backlight.  Fan will be enabled later by whatever
		 * controls the fan power supply.
		 */
		pwm_enable_keyboard_backlight(1);
	}

	/* Initialize memory-mapped data */
	mapped = (uint16_t *)host_get_memmap(EC_MEMMAP_FAN);
	for (i = 0; i < EC_FAN_SPEED_ENTRIES; i++)
		mapped[i] = EC_FAN_SPEED_NOT_PRESENT;

	return EC_SUCCESS;
}
DECLARE_HOOK(HOOK_INIT, pwm_init, HOOK_PRIO_DEFAULT);

static int pwm_preserve_state(void)
{
	struct pwm_state state;

	state.fan_en = pwm_get_fan_enabled();
	state.fan_rpm = pwm_get_fan_target_rpm();
	state.kblight_en = pwm_get_keyboard_backlight_enabled();
	state.kblight_percent = pwm_get_keyboard_backlight();

	system_add_jump_tag(PWM_SYSJUMP_TAG, PWM_HOOK_VERSION,
			    sizeof(state), &state);

	return EC_SUCCESS;
}
DECLARE_HOOK(HOOK_SYSJUMP, pwm_preserve_state, HOOK_PRIO_DEFAULT);

static int pwm_resume(void)
{
	pwm_enable_fan(1);
	return EC_SUCCESS;
}
DECLARE_HOOK(HOOK_CHIPSET_RESUME, pwm_resume, HOOK_PRIO_DEFAULT);

static int pwm_suspend(void)
{
	pwm_enable_fan(0);
	pwm_set_fan_target_rpm(0);
	pwm_set_keyboard_backlight(0);
	return EC_SUCCESS;
}
DECLARE_HOOK(HOOK_CHIPSET_SUSPEND, pwm_suspend, HOOK_PRIO_DEFAULT);

static int pwm_shutdown(void)
{
	pwm_set_keyboard_backlight(0);
	return EC_SUCCESS;
}
DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, pwm_shutdown, HOOK_PRIO_DEFAULT);