/*
 * OMAP4 Power Management Routines
 *
 * Copyright (C) 2010-2011 Texas Instruments, Inc.
 * Rajendra Nayak <rnayak@ti.com>
 * Santosh Shilimkar <santosh.shilimkar@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/pm.h>
#include <linux/suspend.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <asm/system_misc.h>

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

struct power_state {
	struct powerdomain *pwrdm;
	u32 next_state;
#ifdef CONFIG_SUSPEND
	u32 saved_state;
	u32 saved_logic_state;
#endif
	struct list_head node;
};

static LIST_HEAD(pwrst_list);

#ifdef CONFIG_SUSPEND
static int omap4_pm_suspend(void)
{
	struct power_state *pwrst;
	int state, ret = 0;
	u32 cpu_id = smp_processor_id();

	/* Save current powerdomain state */
	list_for_each_entry(pwrst, &pwrst_list, node) {
		pwrst->saved_state = pwrdm_read_next_pwrst(pwrst->pwrdm);
		pwrst->saved_logic_state = pwrdm_read_logic_retst(pwrst->pwrdm);
	}

	/* Set targeted power domain states by suspend */
	list_for_each_entry(pwrst, &pwrst_list, node) {
		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
		pwrdm_set_logic_retst(pwrst->pwrdm, PWRDM_POWER_OFF);
	}

	/*
	 * For MPUSS to hit power domain retention(CSWR or OSWR),
	 * CPU0 and CPU1 power domains need to be in OFF or DORMANT state,
	 * since CPU power domain CSWR is not supported by hardware
	 * Only master CPU follows suspend path. All other CPUs follow
	 * CPU hotplug path in system wide suspend. On OMAP4, CPU power
	 * domain CSWR is not supported by hardware.
	 * More details can be found in OMAP4430 TRM section 4.3.4.2.
	 */
	omap4_enter_lowpower(cpu_id, PWRDM_POWER_OFF);

	/* Restore next powerdomain state */
	list_for_each_entry(pwrst, &pwrst_list, node) {
		state = pwrdm_read_prev_pwrst(pwrst->pwrdm);
		if (state > pwrst->next_state) {
			pr_info("Powerdomain (%s) didn't enter "
			       "target state %d\n",
			       pwrst->pwrdm->name, pwrst->next_state);
			ret = -1;
		}
		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->saved_state);
		pwrdm_set_logic_retst(pwrst->pwrdm, pwrst->saved_logic_state);
	}
	if (ret)
		pr_crit("Could not enter target state in pm_suspend\n");
	else
		pr_info("Successfully put all powerdomains to target state\n");

	return 0;
}

static int omap4_pm_enter(suspend_state_t suspend_state)
{
	int ret = 0;

	switch (suspend_state) {
	case PM_SUSPEND_STANDBY:
	case PM_SUSPEND_MEM:
		ret = omap4_pm_suspend();
		break;
	default:
		ret = -EINVAL;
	}

	return ret;
}

static int omap4_pm_begin(suspend_state_t state)
{
	disable_hlt();
	return 0;
}

static void omap4_pm_end(void)
{
	enable_hlt();
	return;
}

static const struct platform_suspend_ops omap_pm_ops = {
	.begin		= omap4_pm_begin,
	.end		= omap4_pm_end,
	.enter		= omap4_pm_enter,
	.valid		= suspend_valid_only_mem,
};
#endif /* CONFIG_SUSPEND */

/*
 * Enable hardware supervised mode for all clockdomains if it's
 * supported. Initiate sleep transition for other clockdomains, if
 * they are not used
 */
static int __init clkdms_setup(struct clockdomain *clkdm, void *unused)
{
	if (clkdm->flags & CLKDM_CAN_ENABLE_AUTO)
		clkdm_allow_idle(clkdm);
	else if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP &&
			atomic_read(&clkdm->usecount) == 0)
		clkdm_sleep(clkdm);
	return 0;
}


static int __init pwrdms_setup(struct powerdomain *pwrdm, void *unused)
{
	struct power_state *pwrst;

	if (!pwrdm->pwrsts)
		return 0;

	/*
	 * Skip CPU0 and CPU1 power domains. CPU1 is programmed
	 * through hotplug path and CPU0 explicitly programmed
	 * further down in the code path
	 */
	if (!strncmp(pwrdm->name, "cpu", 3))
		return 0;

	/*
	 * FIXME: Remove this check when core retention is supported
	 * Only MPUSS power domain is added in the list.
	 */
	if (strcmp(pwrdm->name, "mpu_pwrdm"))
		return 0;

	pwrst = kmalloc(sizeof(struct power_state), GFP_ATOMIC);
	if (!pwrst)
		return -ENOMEM;

	pwrst->pwrdm = pwrdm;
	pwrst->next_state = PWRDM_POWER_RET;
	list_add(&pwrst->node, &pwrst_list);

	return omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
}

/**
 * omap_default_idle - OMAP4 default ilde routine.'
 *
 * Implements OMAP4 memory, IO ordering requirements which can't be addressed
 * with default arch_idle() hook. Used by all CPUs with !CONFIG_CPUIDLE and
 * by secondary CPU with CONFIG_CPUIDLE.
 */
static void omap_default_idle(void)
{
	local_irq_disable();
	local_fiq_disable();

	omap_do_wfi();

	local_fiq_enable();
	local_irq_enable();
}

/**
 * omap4_pm_init - Init routine for OMAP4 PM
 *
 * Initializes all powerdomain and clockdomain target states
 * and all PRCM settings.
 */
static int __init omap4_pm_init(void)
{
	int ret;
	struct clockdomain *emif_clkdm, *mpuss_clkdm, *l3_1_clkdm;
	struct clockdomain *ducati_clkdm, *l3_2_clkdm, *l4_per_clkdm;

	if (!cpu_is_omap44xx())
		return -ENODEV;

	if (omap_rev() == OMAP4430_REV_ES1_0) {
		WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
		return -ENODEV;
	}

	pr_err("Power Management for TI OMAP4.\n");

	ret = pwrdm_for_each(pwrdms_setup, NULL);
	if (ret) {
		pr_err("Failed to setup powerdomains\n");
		goto err2;
	}

	/*
	 * The dynamic dependency between MPUSS -> MEMIF and
	 * MPUSS -> L4_PER/L3_* and DUCATI -> L3_* doesn't work as
	 * expected. The hardware recommendation is to enable static
	 * dependencies for these to avoid system lock ups or random crashes.
	 */
	mpuss_clkdm = clkdm_lookup("mpuss_clkdm");
	emif_clkdm = clkdm_lookup("l3_emif_clkdm");
	l3_1_clkdm = clkdm_lookup("l3_1_clkdm");
	l3_2_clkdm = clkdm_lookup("l3_2_clkdm");
	l4_per_clkdm = clkdm_lookup("l4_per_clkdm");
	ducati_clkdm = clkdm_lookup("ducati_clkdm");
	if ((!mpuss_clkdm) || (!emif_clkdm) || (!l3_1_clkdm) ||
		(!l3_2_clkdm) || (!ducati_clkdm) || (!l4_per_clkdm))
		goto err2;

	ret = clkdm_add_wkdep(mpuss_clkdm, emif_clkdm);
	ret |= clkdm_add_wkdep(mpuss_clkdm, l3_1_clkdm);
	ret |= clkdm_add_wkdep(mpuss_clkdm, l3_2_clkdm);
	ret |= clkdm_add_wkdep(mpuss_clkdm, l4_per_clkdm);
	ret |= clkdm_add_wkdep(ducati_clkdm, l3_1_clkdm);
	ret |= clkdm_add_wkdep(ducati_clkdm, l3_2_clkdm);
	if (ret) {
		pr_err("Failed to add MPUSS -> L3/EMIF/L4PER, DUCATI -> L3 "
				"wakeup dependency\n");
		goto err2;
	}

	ret = omap4_mpuss_init();
	if (ret) {
		pr_err("Failed to initialise OMAP4 MPUSS\n");
		goto err2;
	}

	(void) clkdm_for_each(clkdms_setup, NULL);

#ifdef CONFIG_SUSPEND
	suspend_set_ops(&omap_pm_ops);
#endif /* CONFIG_SUSPEND */

	/* Overwrite the default arch_idle() */
	pm_idle = omap_default_idle;

	omap4_idle_init();

err2:
	return ret;
}
late_initcall(omap4_pm_init);