ARM: ux500: add the cpuidle driver for WFI and ARM retention

obj-y				:= clock.o cpu.o devices.o devices-common.o \

				   id.o usb.o timer.o

obj-$(CONFIG_CPU_IDLE)          += cpuidle.o

obj-$(CONFIG_CACHE_L2X0)	+= cache-l2x0.o

obj-$(CONFIG_UX500_SOC_DB5500)	+= cpu-db5500.o dma-db5500.o

obj-$(CONFIG_UX500_SOC_DB8500)	+= cpu-db8500.o devices-db8500.o

/*

 * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)

 *

 * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>

 * and Jonas Aaberg <jonas.aberg@stericsson.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/module.h>

#include <linux/cpuidle.h>

#include <linux/clockchips.h>

#include <linux/spinlock.h>

#include <linux/atomic.h>

#include <linux/smp.h>

#include <linux/mfd/dbx500-prcmu.h>

#include <asm/cpuidle.h>

#include <asm/proc-fns.h>

static atomic_t master = ATOMIC_INIT(0);

static DEFINE_SPINLOCK(master_lock);

static DEFINE_PER_CPU(struct cpuidle_device, ux500_cpuidle_device);

static inline int ux500_enter_idle(struct cpuidle_device *dev,

				   struct cpuidle_driver *drv, int index)

{

	int this_cpu = smp_processor_id();

	bool recouple = false;

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);

	if (atomic_inc_return(&master) == num_online_cpus()) {

		/* With this lock, we prevent the other cpu to exit and enter

		 * this function again and become the master */

		if (!spin_trylock(&master_lock))

			goto wfi;

		/* decouple the gic from the A9 cores */

		if (prcmu_gic_decouple())

			goto out;

		/* If an error occur, we will have to recouple the gic

		 * manually */

		recouple = true;

		/* At this state, as the gic is decoupled, if the other

		 * cpu is in WFI, we have the guarantee it won't be wake

		 * up, so we can safely go to retention */

		if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))

			goto out;

		/* The prcmu will be in charge of watching the interrupts

		 * and wake up the cpus */

		if (prcmu_copy_gic_settings())

			goto out;

		/* Check in the meantime an interrupt did

		 * not occur on the gic ... */

		if (prcmu_gic_pending_irq())

			goto out;

		/* ... and the prcmu */

		if (prcmu_pending_irq())

			goto out;

		/* Go to the retention state, the prcmu will wait for the

		 * cpu to go WFI and this is what happens after exiting this

		 * 'master' critical section */

		if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))

			goto out;

		/* When we switch to retention, the prcmu is in charge

		 * of recoupling the gic automatically */

		recouple = false;

		spin_unlock(&master_lock);

	}

wfi:

	cpu_do_idle();

out:

	atomic_dec(&master);

	if (recouple) {

		prcmu_gic_recouple();

		spin_unlock(&master_lock);

	}

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);

	return index;

}

static struct cpuidle_driver ux500_idle_driver = {

	.name = "ux500_idle",

	.owner = THIS_MODULE,

	.en_core_tk_irqen = 1,

	.states = {

		ARM_CPUIDLE_WFI_STATE,

		{

			.enter		  = ux500_enter_idle,

			.exit_latency	  = 70,

			.target_residency = 260,

			.flags		  = CPUIDLE_FLAG_TIME_VALID,

			.name		  = "ApIdle",

			.desc		  = "ARM Retention",

		},

	},

	.safe_state_index = 0,

	.state_count = 2,

};

/*

 * For each cpu, setup the broadcast timer because we will

 * need to migrate the timers for the states >= ApIdle.

 */

static void ux500_setup_broadcast_timer(void *arg)

{

	int cpu = smp_processor_id();

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);

}

int __init ux500_idle_init(void)

{

	int ret, cpu;

	struct cpuidle_device *device;

        /* Configure wake up reasons */

	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |

			     PRCMU_WAKEUP(ABB));

	/*

	 * Configure the timer broadcast for each cpu, that must

	 * be done from the cpu context, so we use a smp cross

	 * call with 'on_each_cpu'.

	 */

	on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);

	ret = cpuidle_register_driver(&ux500_idle_driver);

	if (ret) {

		printk(KERN_ERR "failed to register ux500 idle driver\n");

		return ret;

	}

	for_each_online_cpu(cpu) {

		device = &per_cpu(ux500_cpuidle_device, cpu);

		device->cpu = cpu;

		ret = cpuidle_register_device(device);

		if (ret) {

			printk(KERN_ERR "Failed to register cpuidle "

			       "device for cpu%d\n", cpu);

			goto out_unregister;

		}

	}

out:

	return ret;

out_unregister:

	for_each_online_cpu(cpu) {

		device = &per_cpu(ux500_cpuidle_device, cpu);

		cpuidle_unregister_device(device);

	}

	cpuidle_unregister_driver(&ux500_idle_driver);

	goto out;

}

device_initcall(ux500_idle_init);