linux/arch/arm/mach-exynos/pm.c

/*
 * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * EXYNOS - Power Management support
 *
 * Based on arch/arm/mach-s3c2410/pm.c
 * Copyright (c) 2006 Simtec Electronics
 *	Ben Dooks <ben@simtec.co.uk>
 *
 * 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/init.h>
#include <linux/suspend.h>
#include <linux/cpu_pm.h>
#include <linux/io.h>
#include <linux/err.h>

#include <asm/firmware.h>
#include <asm/smp_scu.h>
#include <asm/suspend.h>

#include <plat/pm-common.h>

#include "common.h"
#include "exynos-pmu.h"
#include "regs-pmu.h"
#include "regs-sys.h"

static inline void __iomem *exynos_boot_vector_addr(void)
{
	if (samsung_rev() == EXYNOS4210_REV_1_1)
		return pmu_base_addr + S5P_INFORM7;
	else if (samsung_rev() == EXYNOS4210_REV_1_0)
		return sysram_base_addr + 0x24;
	return pmu_base_addr + S5P_INFORM0;
}

static inline void __iomem *exynos_boot_vector_flag(void)
{
	if (samsung_rev() == EXYNOS4210_REV_1_1)
		return pmu_base_addr + S5P_INFORM6;
	else if (samsung_rev() == EXYNOS4210_REV_1_0)
		return sysram_base_addr + 0x20;
	return pmu_base_addr + S5P_INFORM1;
}

#define S5P_CHECK_AFTR  0xFCBA0D10

/* For Cortex-A9 Diagnostic and Power control register */
static unsigned int save_arm_register[2];

void exynos_cpu_save_register(void)
{
	unsigned long tmp;

	/* Save Power control register */
	asm ("mrc p15, 0, %0, c15, c0, 0"
	     : "=r" (tmp) : : "cc");

	save_arm_register[0] = tmp;

	/* Save Diagnostic register */
	asm ("mrc p15, 0, %0, c15, c0, 1"
	     : "=r" (tmp) : : "cc");

	save_arm_register[1] = tmp;
}

void exynos_cpu_restore_register(void)
{
	unsigned long tmp;

	/* Restore Power control register */
	tmp = save_arm_register[0];

	asm volatile ("mcr p15, 0, %0, c15, c0, 0"
		      : : "r" (tmp)
		      : "cc");

	/* Restore Diagnostic register */
	tmp = save_arm_register[1];

	asm volatile ("mcr p15, 0, %0, c15, c0, 1"
		      : : "r" (tmp)
		      : "cc");
}

void exynos_pm_central_suspend(void)
{
	unsigned long tmp;

	/* Setting Central Sequence Register for power down mode */
	tmp = pmu_raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
	tmp &= ~S5P_CENTRAL_LOWPWR_CFG;
	pmu_raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);

	/* Setting SEQ_OPTION register */
	pmu_raw_writel(S5P_USE_STANDBY_WFI0 | S5P_USE_STANDBY_WFE0,
		       S5P_CENTRAL_SEQ_OPTION);
}

int exynos_pm_central_resume(void)
{
	unsigned long tmp;

	/*
	 * If PMU failed while entering sleep mode, WFI will be
	 * ignored by PMU and then exiting cpu_do_idle().
	 * S5P_CENTRAL_LOWPWR_CFG bit will not be set automatically
	 * in this situation.
	 */
	tmp = pmu_raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
	if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
		tmp |= S5P_CENTRAL_LOWPWR_CFG;
		pmu_raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
		/* clear the wakeup state register */
		pmu_raw_writel(0x0, S5P_WAKEUP_STAT);
		/* No need to perform below restore code */
		return -1;
	}

	return 0;
}

/* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
static void exynos_set_wakeupmask(long mask)
{
	pmu_raw_writel(mask, S5P_WAKEUP_MASK);
}

static void exynos_cpu_set_boot_vector(long flags)
{
	__raw_writel(virt_to_phys(exynos_cpu_resume),
		     exynos_boot_vector_addr());
	__raw_writel(flags, exynos_boot_vector_flag());
}

static int exynos_aftr_finisher(unsigned long flags)
{
	int ret;

	exynos_set_wakeupmask(0x0000ff3e);
	/* Set value of power down register for aftr mode */
	exynos_sys_powerdown_conf(SYS_AFTR);

	ret = call_firmware_op(do_idle, FW_DO_IDLE_AFTR);
	if (ret == -ENOSYS) {
		if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9)
			exynos_cpu_save_register();
		exynos_cpu_set_boot_vector(S5P_CHECK_AFTR);
		cpu_do_idle();
	}

	return 1;
}

void exynos_enter_aftr(void)
{
	cpu_pm_enter();

	exynos_pm_central_suspend();

	cpu_suspend(0, exynos_aftr_finisher);

	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
		scu_enable(S5P_VA_SCU);
		if (call_firmware_op(resume) == -ENOSYS)
			exynos_cpu_restore_register();
	}

	exynos_pm_central_resume();

	cpu_pm_exit();
}