/*
 * OMAP4 CPU idle Routines
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Santosh Shilimkar <santosh.shilimkar@ti.com>
 * Rajendra Nayak <rnayak@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/sched.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/export.h>
#include <linux/clockchips.h>

#include <asm/proc-fns.h>

#include "common.h"
#include "pm.h"
#include "prm.h"

#ifdef CONFIG_CPU_IDLE

/* Machine specific information to be recorded in the C-state driver_data */
struct omap4_idle_statedata {
	u32 cpu_state;
	u32 mpu_logic_state;
	u32 mpu_state;
	u8 valid;
};

static struct cpuidle_params cpuidle_params_table[] = {
	/* C1 - CPU0 ON + CPU1 ON + MPU ON */
	{.exit_latency = 2 + 2 , .target_residency = 5, .valid = 1},
	/* C2- CPU0 OFF + CPU1 OFF + MPU CSWR */
	{.exit_latency = 328 + 440 , .target_residency = 960, .valid = 1},
	/* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
	{.exit_latency = 460 + 518 , .target_residency = 1100, .valid = 1},
};

#define OMAP4_NUM_STATES ARRAY_SIZE(cpuidle_params_table)

struct omap4_idle_statedata omap4_idle_data[OMAP4_NUM_STATES];
static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd;

/**
 * omap4_enter_idle - Programs OMAP4 to enter the specified state
 * @dev: cpuidle device
 * @drv: cpuidle driver
 * @index: the index of state to be entered
 *
 * Called from the CPUidle framework to program the device to the
 * specified low power state selected by the governor.
 * Returns the amount of time spent in the low power state.
 */
static int omap4_enter_idle(struct cpuidle_device *dev,
			struct cpuidle_driver *drv,
			int index)
{
	struct omap4_idle_statedata *cx =
			cpuidle_get_statedata(&dev->states_usage[index]);
	struct timespec ts_preidle, ts_postidle, ts_idle;
	u32 cpu1_state;
	int idle_time;
	int cpu_id = smp_processor_id();

	/* Used to keep track of the total time in idle */
	getnstimeofday(&ts_preidle);

	local_irq_disable();
	local_fiq_disable();

	/*
	 * CPU0 has to stay ON (i.e in C1) until CPU1 is OFF state.
	 * This is necessary to honour hardware recommondation
	 * of triggeing all the possible low power modes once CPU1 is
	 * out of coherency and in OFF mode.
	 * Update dev->last_state so that governor stats reflects right
	 * data.
	 */
	cpu1_state = pwrdm_read_pwrst(cpu1_pd);
	if (cpu1_state != PWRDM_POWER_OFF) {
		index = drv->safe_state_index;
		cx = cpuidle_get_statedata(&dev->states_usage[index]);
	}

	if (index > 0)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);

	/*
	 * Call idle CPU PM enter notifier chain so that
	 * VFP and per CPU interrupt context is saved.
	 */
	if (cx->cpu_state == PWRDM_POWER_OFF)
		cpu_pm_enter();

	pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
	omap_set_pwrdm_state(mpu_pd, cx->mpu_state);

	/*
	 * Call idle CPU cluster PM enter notifier chain
	 * to save GIC and wakeupgen context.
	 */
	if ((cx->mpu_state == PWRDM_POWER_RET) &&
		(cx->mpu_logic_state == PWRDM_POWER_OFF))
			cpu_cluster_pm_enter();

	omap4_enter_lowpower(dev->cpu, cx->cpu_state);

	/*
	 * Call idle CPU PM exit notifier chain to restore
	 * VFP and per CPU IRQ context. Only CPU0 state is
	 * considered since CPU1 is managed by CPU hotplug.
	 */
	if (pwrdm_read_prev_pwrst(cpu0_pd) == PWRDM_POWER_OFF)
		cpu_pm_exit();

	/*
	 * Call idle CPU cluster PM exit notifier chain
	 * to restore GIC and wakeupgen context.
	 */
	if (omap4_mpuss_read_prev_context_state())
		cpu_cluster_pm_exit();

	if (index > 0)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);

	getnstimeofday(&ts_postidle);
	ts_idle = timespec_sub(ts_postidle, ts_preidle);

	local_irq_enable();
	local_fiq_enable();

	idle_time = ts_idle.tv_nsec / NSEC_PER_USEC + ts_idle.tv_sec * \
								USEC_PER_SEC;

	/* Update cpuidle counters */
	dev->last_residency = idle_time;

	return index;
}

DEFINE_PER_CPU(struct cpuidle_device, omap4_idle_dev);

struct cpuidle_driver omap4_idle_driver = {
	.name =		"omap4_idle",
	.owner =	THIS_MODULE,
};

static inline void _fill_cstate(struct cpuidle_driver *drv,
					int idx, const char *descr)
{
	struct cpuidle_state *state = &drv->states[idx];

	state->exit_latency	= cpuidle_params_table[idx].exit_latency;
	state->target_residency	= cpuidle_params_table[idx].target_residency;
	state->flags		= CPUIDLE_FLAG_TIME_VALID;
	state->enter		= omap4_enter_idle;
	sprintf(state->name, "C%d", idx + 1);
	strncpy(state->desc, descr, CPUIDLE_DESC_LEN);
}

static inline struct omap4_idle_statedata *_fill_cstate_usage(
					struct cpuidle_device *dev,
					int idx)
{
	struct omap4_idle_statedata *cx = &omap4_idle_data[idx];
	struct cpuidle_state_usage *state_usage = &dev->states_usage[idx];

	cx->valid		= cpuidle_params_table[idx].valid;
	cpuidle_set_statedata(state_usage, cx);

	return cx;
}


/**
 * omap4_idle_init - Init routine for OMAP4 idle
 *
 * Registers the OMAP4 specific cpuidle driver to the cpuidle
 * framework with the valid set of states.
 */
int __init omap4_idle_init(void)
{
	struct omap4_idle_statedata *cx;
	struct cpuidle_device *dev;
	struct cpuidle_driver *drv = &omap4_idle_driver;
	unsigned int cpu_id = 0;

	mpu_pd = pwrdm_lookup("mpu_pwrdm");
	cpu0_pd = pwrdm_lookup("cpu0_pwrdm");
	cpu1_pd = pwrdm_lookup("cpu1_pwrdm");
	if ((!mpu_pd) || (!cpu0_pd) || (!cpu1_pd))
		return -ENODEV;


	drv->safe_state_index = -1;
	dev = &per_cpu(omap4_idle_dev, cpu_id);
	dev->cpu = cpu_id;

	/* C1 - CPU0 ON + CPU1 ON + MPU ON */
	_fill_cstate(drv, 0, "MPUSS ON");
	drv->safe_state_index = 0;
	cx = _fill_cstate_usage(dev, 0);
	cx->valid = 1;	/* C1 is always valid */
	cx->cpu_state = PWRDM_POWER_ON;
	cx->mpu_state = PWRDM_POWER_ON;
	cx->mpu_logic_state = PWRDM_POWER_RET;

	/* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
	_fill_cstate(drv, 1, "MPUSS CSWR");
	cx = _fill_cstate_usage(dev, 1);
	cx->cpu_state = PWRDM_POWER_OFF;
	cx->mpu_state = PWRDM_POWER_RET;
	cx->mpu_logic_state = PWRDM_POWER_RET;

	/* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
	_fill_cstate(drv, 2, "MPUSS OSWR");
	cx = _fill_cstate_usage(dev, 2);
	cx->cpu_state = PWRDM_POWER_OFF;
	cx->mpu_state = PWRDM_POWER_RET;
	cx->mpu_logic_state = PWRDM_POWER_OFF;

	drv->state_count = OMAP4_NUM_STATES;
	cpuidle_register_driver(&omap4_idle_driver);

	dev->state_count = OMAP4_NUM_STATES;
	if (cpuidle_register_device(dev)) {
		pr_err("%s: CPUidle register device failed\n", __func__);
			return -EIO;
		}

	return 0;
}
#else
int __init omap4_idle_init(void)
{
	return 0;
}
#endif /* CONFIG_CPU_IDLE */