/*
 * OMAP4+ CPU idle Routines
 *
 * Copyright (C) 2011-2013 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/tick.h>

#include <asm/cpuidle.h>

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

#define MAX_CPUS        2

/* Machine specific information */
struct idle_statedata {
        u32 cpu_state;
        u32 mpu_logic_state;
        u32 mpu_state;
};

static struct idle_statedata omap4_idle_data[] = {
        {
                .cpu_state = PWRDM_POWER_ON,
                .mpu_state = PWRDM_POWER_ON,
                .mpu_logic_state = PWRDM_POWER_RET,
        },
        {
                .cpu_state = PWRDM_POWER_OFF,
                .mpu_state = PWRDM_POWER_RET,
                .mpu_logic_state = PWRDM_POWER_RET,
        },
        {
                .cpu_state = PWRDM_POWER_OFF,
                .mpu_state = PWRDM_POWER_RET,
                .mpu_logic_state = PWRDM_POWER_OFF,
        },
};

static struct powerdomain *mpu_pd, *cpu_pd[MAX_CPUS];
static struct clockdomain *cpu_clkdm[MAX_CPUS];

static atomic_t abort_barrier;
static bool cpu_done[MAX_CPUS];
static struct idle_statedata *state_ptr = &omap4_idle_data[0];

/* Private functions */

/**
 * omap_enter_idle_[simple/coupled] - OMAP4PLUS cpuidle entry functions
 * @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 omap_enter_idle_simple(struct cpuidle_device *dev,
                        struct cpuidle_driver *drv,
                        int index)
{
        omap_do_wfi();
        return index;
}

static int omap_enter_idle_coupled(struct cpuidle_device *dev,
                        struct cpuidle_driver *drv,
                        int index)
{
        struct idle_statedata *cx = state_ptr + index;
        u32 mpuss_can_lose_context = 0;

        /*
         * CPU0 has to wait and stay ON 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.
         */
        if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {
                while (pwrdm_read_pwrst(cpu_pd[1]) != PWRDM_POWER_OFF) {
                        cpu_relax();

                        /*
                         * CPU1 could have already entered & exited idle
                         * without hitting off because of a wakeup
                         * or a failed attempt to hit off mode.  Check for
                         * that here, otherwise we could spin forever
                         * waiting for CPU1 off.
                         */
                        if (cpu_done[1])
                            goto fail;

                }
        }

        mpuss_can_lose_context = (cx->mpu_state == PWRDM_POWER_RET) &&
                                 (cx->mpu_logic_state == PWRDM_POWER_OFF);

        tick_broadcast_enter();

        /*
         * Call idle CPU PM enter notifier chain so that
         * VFP and per CPU interrupt context is saved.
         */
        cpu_pm_enter();

        if (dev->cpu == 0) {
                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 (mpuss_can_lose_context)
                        cpu_cluster_pm_enter();
        }

        omap4_enter_lowpower(dev->cpu, cx->cpu_state);
        cpu_done[dev->cpu] = true;

        /* Wakeup CPU1 only if it is not offlined */
        if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {

                if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
                    mpuss_can_lose_context)
                        gic_dist_disable();

                clkdm_wakeup(cpu_clkdm[1]);
                omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON);
                clkdm_allow_idle(cpu_clkdm[1]);

                if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) &&
                    mpuss_can_lose_context) {
                        while (gic_dist_disabled()) {
                                udelay(1);
                                cpu_relax();
                        }
                        gic_timer_retrigger();
                }
        }

        /*
         * Call idle CPU PM exit notifier chain to restore
         * VFP and per CPU IRQ context.
         */
        cpu_pm_exit();

        /*
         * Call idle CPU cluster PM exit notifier chain
         * to restore GIC and wakeupgen context.
         */
        if (dev->cpu == 0 && mpuss_can_lose_context)
                cpu_cluster_pm_exit();

        tick_broadcast_exit();

fail:
        cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
        cpu_done[dev->cpu] = false;

        return index;
}

/*
 * For each cpu, setup the broadcast timer because local timers
 * stops for the states above C1.
 */
static void omap_setup_broadcast_timer(void *arg)
{
        tick_broadcast_enable();
}

static struct cpuidle_driver omap4_idle_driver = {
        .name                           = "omap4_idle",
        .owner                          = THIS_MODULE,
        .states = {
                {
                        /* C1 - CPU0 ON + CPU1 ON + MPU ON */
                        .exit_latency = 2 + 2,
                        .target_residency = 5,
                        .enter = omap_enter_idle_simple,
                        .name = "C1",
                        .desc = "CPUx ON, MPUSS ON"
                },
                {
                        /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
                        .exit_latency = 328 + 440,
                        .target_residency = 960,
                        .flags = CPUIDLE_FLAG_COUPLED,
                        .enter = omap_enter_idle_coupled,
                        .name = "C2",
                        .desc = "CPUx OFF, MPUSS CSWR",
                },
                {
                        /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
                        .exit_latency = 460 + 518,
                        .target_residency = 1100,
                        .flags = CPUIDLE_FLAG_COUPLED,
                        .enter = omap_enter_idle_coupled,
                        .name = "C3",
                        .desc = "CPUx OFF, MPUSS OSWR",
                },
        },
        .state_count = ARRAY_SIZE(omap4_idle_data),
        .safe_state_index = 0,
};

/* Public functions */

/**
 * 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)
{
        mpu_pd = pwrdm_lookup("mpu_pwrdm");
        cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");
        cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");
        if ((!mpu_pd) || (!cpu_pd[0]) || (!cpu_pd[1]))
                return -ENODEV;

        cpu_clkdm[0] = clkdm_lookup("mpu0_clkdm");
        cpu_clkdm[1] = clkdm_lookup("mpu1_clkdm");
        if (!cpu_clkdm[0] || !cpu_clkdm[1])
                return -ENODEV;

        /* Configure the broadcast timer on each cpu */
        on_each_cpu(omap_setup_broadcast_timer, NULL, 1);

        return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
}