OpenCellular/common/charge_state.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.
 *
 * Battery charging task and state machine.
 */


#include "battery.h"
#include "battery_pack.h"
#include "board.h"
#include "charge_state.h"
#include "charger.h"
#include "chipset.h"
#include "console.h"
#include "gpio.h"
#include "lpc.h"
#include "lpc_commands.h"
#include "power_led.h"
#include "smart_battery.h"
#include "system.h"
#include "timer.h"
#include "uart.h"
#include "util.h"
#include "x86_power.h"

/* Stop charge when state of charge reaches this percentage */
#define STOP_CHARGE_THRESHOLD 100

static const char * const state_name[] = POWER_STATE_NAME_TABLE;

/* helper function(s) */
static inline int get_ac(void)
{
	return gpio_get_level(GPIO_AC_PRESENT);
}

/* Battery information used to fill ACPI _BIF and/or _BIX */
static void update_battery_info(void)
{
	char *batt_str;
	int batt_serial;

	/* Design Capacity of Full */
	battery_design_capacity((int *)(lpc_get_memmap_range() +
					EC_LPC_MEMMAP_BATT_DCAP));

	/* Design Voltage */
	battery_design_voltage((int *)(lpc_get_memmap_range() +
				       EC_LPC_MEMMAP_BATT_DVLT));

	/* Last Full Charge Capacity */
	battery_full_charge_capacity((int *)(lpc_get_memmap_range() +
					     EC_LPC_MEMMAP_BATT_LFCC));

	/* Cycle Count */
	battery_cycle_count((int *)(lpc_get_memmap_range() +
				    EC_LPC_MEMMAP_BATT_CCNT));

	/* Battery Manufacturer string */
	batt_str = (char *)(lpc_get_memmap_range() + EC_LPC_MEMMAP_BATT_MFGR);
	memset(batt_str, 0, EC_LPC_MEMMAP_TEXT_MAX);
	battery_manufacturer_name(batt_str, EC_LPC_MEMMAP_TEXT_MAX);

	/* Battery Model string */
	batt_str = (char *)(lpc_get_memmap_range() + EC_LPC_MEMMAP_BATT_MODEL);
	memset(batt_str, 0, EC_LPC_MEMMAP_TEXT_MAX);
	battery_device_name(batt_str, EC_LPC_MEMMAP_TEXT_MAX);

	/* Battery Type string */
	batt_str = (char *)(lpc_get_memmap_range() + EC_LPC_MEMMAP_BATT_TYPE);
	battery_device_chemistry(batt_str, EC_LPC_MEMMAP_TEXT_MAX);

	/* Smart battery serial number is 16 bits */
	batt_str = (char *)(lpc_get_memmap_range() + EC_LPC_MEMMAP_BATT_SERIAL);
	memset(batt_str, 0, EC_LPC_MEMMAP_TEXT_MAX);
	if (battery_serial_number(&batt_serial) == 0) {
		*batt_str++ = hex2asc(0xf & (batt_serial >> 12));
		*batt_str++ = hex2asc(0xf & (batt_serial >> 8));
		*batt_str++ = hex2asc(0xf & (batt_serial >> 4));
		*batt_str++ = hex2asc(0xf & batt_serial);
	}
}

/* Prevent battery from going into deep discharge state */
static void poweroff_wait_ac(void)
{
	/* Shutdown the main processor */
	if (chipset_in_state(CHIPSET_STATE_ON)) {
		/* chipset_force_state(CHIPSET_STATE_SOFT_OFF);
		 * TODO(rong): remove platform dependent code
		 */
#ifdef CONFIG_POWER_X86POWER
		x86_power_force_shutdown();
#endif /* CONFIG_POWER_X86POWER */
	}

	/* TODO(rong): remove this workaround after ec deep sleep */
	while (!get_ac()) {
		/* Check ac_present every 5 seconds */
		usleep(SECOND * 5);
	}
}

/* Common handler for charging states.
 * This handler gets battery charging parameters, charger state, ac state,
 * and timestamp. It also fills memory map and issues power events on state
 * change.
 */
static int state_common(struct power_state_context *ctx)
{
	int rv, d;

	struct power_state_data *curr = &ctx->curr;
	struct power_state_data *prev = &ctx->prev;
	struct batt_params *batt = &ctx->curr.batt;
	uint8_t *batt_flags = ctx->memmap_batt_flags;

	/* Copy previous state and init new state */
	ctx->prev = ctx->curr;
	curr->ts = get_time();
	curr->error = 0;

	/* Detect AC change */
	curr->ac = get_ac();
	if (curr->ac != prev->ac) {
		if (curr->ac) {
			/* AC on
			 *   Initialize charger to power on reset mode
			 */
			rv = charger_post_init();
			if (rv)
				curr->error |= F_CHARGER_INIT;
			lpc_set_host_events(EC_LPC_HOST_EVENT_MASK(
				EC_LPC_HOST_EVENT_AC_CONNECTED));
		} else {
			/* AC off */
			lpc_set_host_events(EC_LPC_HOST_EVENT_MASK(
				EC_LPC_HOST_EVENT_AC_DISCONNECTED));
		}
	}

	if (curr->ac) {
		*batt_flags |= EC_BATT_FLAG_AC_PRESENT;
		rv = charger_get_voltage(&curr->charging_voltage);
		if (rv) {
			charger_set_voltage(0);
			charger_set_current(0);
			curr->error |= F_CHARGER_VOLTAGE;
		}
		rv = charger_get_current(&curr->charging_current);
		if (rv) {
			charger_set_voltage(0);
			charger_set_current(0);
			curr->error |= F_CHARGER_CURRENT;
		}
	} else
		*batt_flags &= ~EC_BATT_FLAG_AC_PRESENT;

	rv = battery_temperature(&batt->temperature);
	if (rv) {
		/* Check low battery condition and retry */
		if (curr->ac && !(curr->error & F_CHARGER_MASK) &&
				(curr->charging_voltage == 0 ||
				curr->charging_current == 0)) {
			charger_set_voltage(ctx->battery->voltage_min);
			charger_set_current(ctx->charger->current_min);
			usleep(SECOND);
			rv = battery_temperature(&batt->temperature);
		}
	}

	if (rv)
		curr->error |= F_BATTERY_TEMPERATURE;

	rv = battery_voltage(&batt->voltage);
	if (rv)
		curr->error |= F_BATTERY_VOLTAGE;
	*ctx->memmap_batt_volt = batt->voltage;

	rv = battery_current(&batt->current);
	if (rv)
		curr->error |= F_BATTERY_CURRENT;
	/* Memory mapped value: discharge rate */
	*ctx->memmap_batt_rate = batt->current < 0 ?
		-batt->current : batt->current;

	rv = battery_desired_voltage(&batt->desired_voltage);
	if (rv)
		curr->error |= F_DESIRED_VOLTAGE;

	rv = battery_desired_current(&batt->desired_current);
	if (rv)
		curr->error |= F_DESIRED_CURRENT;

	rv = battery_state_of_charge(&batt->state_of_charge);
	if (rv)
		curr->error |= F_BATTERY_STATE_OF_CHARGE;

	/* Prevent deep discharging */
	if (!curr->ac)
		if ((batt->state_of_charge < BATTERY_LEVEL_SHUTDOWN &&
		    !(curr->error & F_BATTERY_STATE_OF_CHARGE)) ||
		    (batt->voltage <= ctx->battery->voltage_min &&
		    !(curr->error & F_BATTERY_VOLTAGE)))
			poweroff_wait_ac();

	/* Check battery presence */
	if (curr->error & F_BATTERY_MASK) {
		*ctx->memmap_batt_flags &= ~EC_BATT_FLAG_BATT_PRESENT;
		return curr->error;
	}

	*ctx->memmap_batt_flags |= EC_BATT_FLAG_BATT_PRESENT;

	/* Battery charge level low */
	if (batt->state_of_charge <= BATTERY_LEVEL_LOW &&
			prev->batt.state_of_charge > BATTERY_LEVEL_LOW)
		lpc_set_host_events(EC_LPC_HOST_EVENT_MASK(
			EC_LPC_HOST_EVENT_BATTERY_LOW));

	/* Battery charge level critical */
	if (batt->state_of_charge <= BATTERY_LEVEL_CRITICAL) {
		*ctx->memmap_batt_flags |= EC_BATT_FLAG_LEVEL_CRITICAL;
		/* Send battery critical host event */
		if (prev->batt.state_of_charge > BATTERY_LEVEL_CRITICAL)
			lpc_set_host_events(EC_LPC_HOST_EVENT_MASK(
					EC_LPC_HOST_EVENT_BATTERY_CRITICAL));
	} else
		*ctx->memmap_batt_flags &= ~EC_BATT_FLAG_LEVEL_CRITICAL;


	/* Apply battery pack vendor charging method */
	battery_vendor_params(batt);

#ifdef CONFIG_CHARGING_CURRENT_LIMIT
	if (batt->desired_current > CONFIG_CHARGING_CURRENT_LIMIT)
		batt->desired_current = CONFIG_CHARGING_CURRENT_LIMIT;
#endif

	rv = battery_get_battery_mode(&d);
	if (rv) {
		curr->error |= F_BATTERY_MODE;
	} else {
		if (d & MODE_CAPACITY) {
			/* Battery capacity mode was set to mW
			 * reset it back to mAh
			 */
			d &= ~MODE_CAPACITY;
			rv = battery_set_battery_mode(d);
			if (rv)
				ctx->curr.error |= F_BATTERY_MODE;
		}
	}
	rv = battery_remaining_capacity(&d);
	if (rv)
		ctx->curr.error |= F_BATTERY_CAPACITY;
	else
		*ctx->memmap_batt_cap = d;

	return ctx->curr.error;
}

/* Init state handler
 *	- check ac, charger, battery and temperature
 *	- initialize charger
 *	- new states: DISCHARGE, IDLE
 */
static enum power_state state_init(struct power_state_context *ctx)
{
	/* Stop charger, unconditionally */
	charger_set_current(0);
	charger_set_voltage(0);

	/* If AC is not present, switch to discharging state */
	if (!ctx->curr.ac)
		return PWR_STATE_DISCHARGE;

	/* Check general error conditions */
	if (ctx->curr.error)
		return PWR_STATE_ERROR;

	/* Update static battery info */
	update_battery_info();

	/* Send battery event to host */
	lpc_set_host_events(EC_LPC_HOST_EVENT_MASK(
			    EC_LPC_HOST_EVENT_BATTERY));

	return PWR_STATE_IDLE;
}

/* Idle state handler
 *	- both charger and battery are online
 *	- detect charger and battery status change
 *	- new states: CHARGE, INIT
 */
static enum power_state state_idle(struct power_state_context *ctx)
{
	struct batt_params *batt = &ctx->curr.batt;
	const struct charger_info *c_info = ctx->charger;

	if (!ctx->curr.ac)
		return PWR_STATE_INIT;

	if (ctx->curr.error)
		return PWR_STATE_ERROR;

	/* Prevent charging in idle mode */
	if (ctx->curr.charging_voltage ||
	    ctx->curr.charging_current)
		return PWR_STATE_INIT;

	if (ctx->curr.batt.state_of_charge >= STOP_CHARGE_THRESHOLD)
		return PWR_STATE_UNCHANGE;

	/* Configure init charger state and switch to charge state */
	if (ctx->curr.batt.desired_voltage &&
	    ctx->curr.batt.desired_current) {
		/* Set charger output constraints */
		if (batt->desired_current < ctx->charger->current_min) {
			/* Trickle charging */
			if (charger_set_current(c_info->current_min) ||
			    charger_set_voltage(batt->voltage))
				return PWR_STATE_ERROR;
			ctx->trickle_charging_time = get_time();
		} else {
			/* Normal charging */
			if (charger_set_voltage(batt->desired_voltage) ||
			    charger_set_current(batt->desired_current))
				return PWR_STATE_ERROR;
		}
		ctx->charger_update_time = get_time();
		return PWR_STATE_CHARGE;
	}

	return PWR_STATE_UNCHANGE;
}

/* Charge state handler
 *	- detect battery status change
 *	- new state: INIT
 */
static enum power_state state_charge(struct power_state_context *ctx)
{
	if (ctx->curr.error)
		return PWR_STATE_ERROR;

	if (ctx->curr.batt.desired_current < ctx->charger->current_min)
		return trickle_charge(ctx);

	/* Check charger reset */
	if (ctx->curr.charging_voltage == 0 ||
	    ctx->curr.charging_current == 0)
		return PWR_STATE_INIT;

	if (!ctx->curr.ac)
		return PWR_STATE_INIT;

	if (ctx->curr.batt.state_of_charge >= STOP_CHARGE_THRESHOLD) {
		if (charger_set_voltage(0) || charger_set_current(0))
			return PWR_STATE_ERROR;
		return PWR_STATE_IDLE;
	}

	if ((ctx->curr.batt.desired_voltage != ctx->curr.charging_voltage) ||
	    (ctx->curr.batt.desired_current != ctx->curr.charging_current) ||
	    (ctx->curr.ts.val - ctx->charger_update_time.val >
						CHARGER_UPDATE_PERIOD)) {
		if (ctx->curr.batt.desired_current < ctx->charger->current_min)
			return PWR_STATE_INIT;

		if (charger_set_voltage(ctx->curr.batt.desired_voltage) ||
		    charger_set_current(ctx->curr.batt.desired_current))
			return PWR_STATE_ERROR;
		ctx->charger_update_time = get_time();
	}

	return PWR_STATE_UNCHANGE;
}

/* Discharge state handler
 *	- detect ac status
 *	- new state: INIT
 */
static enum power_state state_discharge(struct power_state_context *ctx)
{
	if (ctx->curr.ac)
		return PWR_STATE_INIT;

	if (ctx->curr.error)
		return PWR_STATE_ERROR;

	/* TODO(rong): crosbug.com/p/8451
	 * handle overtemp in discharge mode
	 */

	return PWR_STATE_UNCHANGE;
}

/* Error state handler
 *	- check charger and battery communication
 *	- log error
 *	- new state: INIT
 */
static enum power_state state_error(struct power_state_context *ctx)
{
	static int logged_error;

	if (!ctx->curr.error) {
		logged_error = 0;
		return PWR_STATE_INIT;
	}

	/* Debug output */
	if (ctx->curr.error != logged_error) {
		uart_printf("[Charge error: flag[%08b -> %08b], ac %d, "
			" charger %s, battery %s\n",
			logged_error, ctx->curr.error, ctx->curr.ac,
			(ctx->curr.error & F_CHARGER_MASK) ?
					"(err)" : "ok",
			(ctx->curr.error & F_BATTERY_MASK) ?
					"(err)" : "ok");

		logged_error = ctx->curr.error;
	}

	return PWR_STATE_UNCHANGE;
}

static void charging_progress(struct power_state_context *ctx)
{
	int seconds, minutes;

	if (ctx->curr.batt.state_of_charge !=
	    ctx->prev.batt.state_of_charge) {
		if (ctx->curr.ac)
			battery_time_to_full(&minutes);
		else
			battery_time_to_empty(&minutes);

		uart_printf("[Battery %3d%% / %dh:%d]\n",
			ctx->curr.batt.state_of_charge,
			minutes / 60, minutes % 60);
		return;
	}

	if (ctx->curr.charging_voltage != ctx->prev.charging_voltage &&
			ctx->trickle_charging_time.val) {
		/* Calculating minutes by dividing usec by 60 million
		 * GNU toolchain generate architecture dependent calls
		 * instead of machine code when the divisor is large.
		 * Hence following calculation was broke into 2 lines.
		 */
		seconds = (int)(get_time().val -
				ctx->trickle_charging_time.val) / (int)SECOND;
		minutes = seconds / 60;
		uart_printf("[Precharge CHG(%dmV) BATT(%dmV %dmA) "
			"%dh:%d]\n", ctx->curr.charging_voltage,
			ctx->curr.batt.voltage, ctx->curr.batt.current,
			minutes / 60, minutes % 60);
	}
}

/* Battery charging task */
void charge_state_machine_task(void)
{
	struct power_state_context ctx;
	timestamp_t ts;
	int sleep_usec, diff_usec;
	enum power_state new_state;
	uint8_t batt_flags;

	ctx.prev.state = PWR_STATE_INIT;
	ctx.curr.state = PWR_STATE_INIT;
	ctx.trickle_charging_time.val = 0;
	ctx.battery = battery_get_info();
	ctx.charger = charger_get_info();

	/* Setup LPC direct memmap */
	ctx.memmap_batt_volt  = (uint32_t *)(lpc_get_memmap_range() +
					EC_LPC_MEMMAP_BATT_VOLT);
	ctx.memmap_batt_rate  = (uint32_t *)(lpc_get_memmap_range() +
					EC_LPC_MEMMAP_BATT_RATE);
	ctx.memmap_batt_cap   = (uint32_t *)(lpc_get_memmap_range() +
					EC_LPC_MEMMAP_BATT_CAP);
	ctx.memmap_batt_flags = (uint8_t *)(lpc_get_memmap_range() +
					EC_LPC_MEMMAP_BATT_FLAG);

	while (1) {

		state_common(&ctx);

		switch (ctx.prev.state) {
		case PWR_STATE_INIT:
			new_state = state_init(&ctx);
			break;
		case PWR_STATE_IDLE:
			new_state = state_idle(&ctx);
			break;
		case PWR_STATE_DISCHARGE:
			new_state = state_discharge(&ctx);
			break;
		case PWR_STATE_CHARGE:
			new_state = state_charge(&ctx);
			break;
		case PWR_STATE_ERROR:
			new_state = state_error(&ctx);
			break;
		default:
			uart_printf("[Undefined charging state %d]\n",
					ctx.curr.state);
			ctx.curr.state = PWR_STATE_ERROR;
			new_state = PWR_STATE_ERROR;
		}

		if (new_state) {
			ctx.curr.state = new_state;
			uart_printf("[Charge state %s -> %s]\n",
				state_name[ctx.prev.state],
				state_name[new_state]);
		}

		switch (new_state) {
		case PWR_STATE_IDLE:
			batt_flags = *ctx.memmap_batt_flags;
			batt_flags &= ~EC_BATT_FLAG_CHARGING;
			batt_flags &= ~EC_BATT_FLAG_DISCHARGING;
			*ctx.memmap_batt_flags = batt_flags;

			/* Charge done */
			powerled_set(POWERLED_GREEN);

			sleep_usec = POLL_PERIOD_LONG;
			break;
		case PWR_STATE_DISCHARGE:
			batt_flags = *ctx.memmap_batt_flags;
			batt_flags &= ~EC_BATT_FLAG_CHARGING;
			batt_flags |= EC_BATT_FLAG_DISCHARGING;
			*ctx.memmap_batt_flags = batt_flags;
			sleep_usec = POLL_PERIOD_LONG;
			break;
		case PWR_STATE_CHARGE:
			batt_flags = *ctx.memmap_batt_flags;
			batt_flags |= EC_BATT_FLAG_CHARGING;
			batt_flags &= ~EC_BATT_FLAG_DISCHARGING;
			*ctx.memmap_batt_flags = batt_flags;

			/* Charging */
			powerled_set(POWERLED_YELLOW);

			sleep_usec = POLL_PERIOD_CHARGE;
			break;
		case PWR_STATE_ERROR:
			/* Error */
			powerled_set(POWERLED_RED);

			sleep_usec = POLL_PERIOD_CHARGE;
		default:
			sleep_usec = POLL_PERIOD_SHORT;
		}

		/* Show charging progress in console */
		charging_progress(&ctx);

		ts = get_time();
		diff_usec = (int)(ts.val - ctx.curr.ts.val);
		sleep_usec -= diff_usec;

		if (sleep_usec < MIN_SLEEP_USEC)
			sleep_usec = MIN_SLEEP_USEC;
		if (sleep_usec > MAX_SLEEP_USEC)
			sleep_usec = MAX_SLEEP_USEC;

		usleep(sleep_usec);
	}
}