arch/arm/mach-at91/pm.c - kernel/msm-4.9 - Gitiles

 /*
  * arch/arm/mach-at91/pm.c
  * AT91 Power Management
  *
  * Copyright (C) 2005 David Brownell
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */

 #include <linux/gpio.h>
 #include <linux/suspend.h>
 #include <linux/sched.h>
 #include <linux/proc_fs.h>
 #include <linux/genalloc.h>
 #include <linux/interrupt.h>
 #include <linux/sysfs.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/atmel.h>
 #include <linux/io.h>
 #include <linux/clk/at91_pmc.h>

 #include <asm/irq.h>
 #include <linux/atomic.h>
 #include <asm/mach/time.h>
 #include <asm/mach/irq.h>
 #include <asm/fncpy.h>
 #include <asm/cacheflush.h>
 #include <asm/system_misc.h>

 #include "generic.h"
 #include "pm.h"

 static void __iomem *pmc;

 /*
  * FIXME: this is needed to communicate between the pinctrl driver and
  * the PM implementation in the machine. Possibly part of the PM
  * implementation should be moved down into the pinctrl driver and get
  * called as part of the generic suspend/resume path.
  */
 #ifdef CONFIG_PINCTRL_AT91
 extern void at91_pinctrl_gpio_suspend(void);
 extern void at91_pinctrl_gpio_resume(void);
 #endif

 static struct {
 	unsigned long uhp_udp_mask;
 	int memctrl;
 } at91_pm_data;

 void __iomem *at91_ramc_base[2];

 static int at91_pm_valid_state(suspend_state_t state)
 {
 	switch (state) {
 		case PM_SUSPEND_ON:
 		case PM_SUSPEND_STANDBY:
 		case PM_SUSPEND_MEM:
 			return 1;

 		default:
 			return 0;
 	}
 }


 static suspend_state_t target_state;

 /*
  * Called after processes are frozen, but before we shutdown devices.
  */
 static int at91_pm_begin(suspend_state_t state)
 {
 	target_state = state;
 	return 0;
 }

 /*
  * Verify that all the clocks are correct before entering
  * slow-clock mode.
  */
 static int at91_pm_verify_clocks(void)
 {
 	unsigned long scsr;
 	int i;

 	scsr = readl(pmc + AT91_PMC_SCSR);

 	/* USB must not be using PLLB */
 	if ((scsr & at91_pm_data.uhp_udp_mask) != 0) {
 		pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
 		return 0;
 	}

 	/* PCK0..PCK3 must be disabled, or configured to use clk32k */
 	for (i = 0; i < 4; i++) {
 		u32 css;

 		if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
 			continue;
 		css = readl(pmc + AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
 		if (css != AT91_PMC_CSS_SLOW) {
 			pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
 			return 0;
 		}
 	}

 	return 1;
 }

 /*
  * Call this from platform driver suspend() to see how deeply to suspend.
  * For example, some controllers (like OHCI) need one of the PLL clocks
  * in order to act as a wakeup source, and those are not available when
  * going into slow clock mode.
  *
  * REVISIT: generalize as clk_will_be_available(clk)?  Other platforms have
  * the very same problem (but not using at91 main_clk), and it'd be better
  * to add one generic API rather than lots of platform-specific ones.
  */
 int at91_suspend_entering_slow_clock(void)
 {
 	return (target_state == PM_SUSPEND_MEM);
 }
 EXPORT_SYMBOL(at91_suspend_entering_slow_clock);

 static void (*at91_suspend_sram_fn)(void __iomem *pmc, void __iomem *ramc0,
 			  void __iomem *ramc1, int memctrl);

 extern void at91_pm_suspend_in_sram(void __iomem *pmc, void __iomem *ramc0,
 			    void __iomem *ramc1, int memctrl);
 extern u32 at91_pm_suspend_in_sram_sz;

 static void at91_pm_suspend(suspend_state_t state)
 {
 	unsigned int pm_data = at91_pm_data.memctrl;

 	pm_data |= (state == PM_SUSPEND_MEM) ?
 				AT91_PM_MODE(AT91_PM_SLOW_CLOCK) : 0;

 	flush_cache_all();
 	outer_disable();

 	at91_suspend_sram_fn(pmc, at91_ramc_base[0],
 			     at91_ramc_base[1], pm_data);

 	outer_resume();
 }

 static int at91_pm_enter(suspend_state_t state)
 {
 #ifdef CONFIG_PINCTRL_AT91
 	at91_pinctrl_gpio_suspend();
 #endif
 	switch (state) {
 	/*
 	 * Suspend-to-RAM is like STANDBY plus slow clock mode, so
 	 * drivers must suspend more deeply, the master clock switches
 	 * to the clk32k and turns off the main oscillator
 	 */
 	case PM_SUSPEND_MEM:
 		/*
 		 * Ensure that clocks are in a valid state.
 		 */
 		if (!at91_pm_verify_clocks())
 			goto error;

 		at91_pm_suspend(state);

 		break;

 	/*
 	 * STANDBY mode has *all* drivers suspended; ignores irqs not
 	 * marked as 'wakeup' event sources; and reduces DRAM power.
 	 * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
 	 * nothing fancy done with main or cpu clocks.
 	 */
 	case PM_SUSPEND_STANDBY:
 		at91_pm_suspend(state);
 		break;

 	case PM_SUSPEND_ON:
 		cpu_do_idle();
 		break;

 	default:
 		pr_debug("AT91: PM - bogus suspend state %d\n", state);
 		goto error;
 	}

 error:
 	target_state = PM_SUSPEND_ON;

 #ifdef CONFIG_PINCTRL_AT91
 	at91_pinctrl_gpio_resume();
 #endif
 	return 0;
 }

 /*
  * Called right prior to thawing processes.
  */
 static void at91_pm_end(void)
 {
 	target_state = PM_SUSPEND_ON;
 }


 static const struct platform_suspend_ops at91_pm_ops = {
 	.valid	= at91_pm_valid_state,
 	.begin	= at91_pm_begin,
 	.enter	= at91_pm_enter,
 	.end	= at91_pm_end,
 };

 static struct platform_device at91_cpuidle_device = {
 	.name = "cpuidle-at91",
 };

 static void at91_pm_set_standby(void (*at91_standby)(void))
 {
 	if (at91_standby)
 		at91_cpuidle_device.dev.platform_data = at91_standby;
 }

 /*
  * The AT91RM9200 goes into self-refresh mode with this command, and will
  * terminate self-refresh automatically on the next SDRAM access.
  *
  * Self-refresh mode is exited as soon as a memory access is made, but we don't
  * know for sure when that happens. However, we need to restore the low-power
  * mode if it was enabled before going idle. Restoring low-power mode while
  * still in self-refresh is "not recommended", but seems to work.
  */
 static void at91rm9200_standby(void)
 {
 	u32 lpr = at91_ramc_read(0, AT91_MC_SDRAMC_LPR);

 	asm volatile(
 		"b    1f\n\t"
 		".align    5\n\t"
 		"1:  mcr    p15, 0, %0, c7, c10, 4\n\t"
 		"    str    %0, [%1, %2]\n\t"
 		"    str    %3, [%1, %4]\n\t"
 		"    mcr    p15, 0, %0, c7, c0, 4\n\t"
 		"    str    %5, [%1, %2]"
 		:
 		: "r" (0), "r" (at91_ramc_base[0]), "r" (AT91_MC_SDRAMC_LPR),
 		  "r" (1), "r" (AT91_MC_SDRAMC_SRR),
 		  "r" (lpr));
 }

 /* We manage both DDRAM/SDRAM controllers, we need more than one value to
  * remember.
  */
 static void at91_ddr_standby(void)
 {
 	/* Those two values allow us to delay self-refresh activation
 	 * to the maximum. */
 	u32 lpr0, lpr1 = 0;
 	u32 saved_lpr0, saved_lpr1 = 0;

 	if (at91_ramc_base[1]) {
 		saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
 		lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
 		lpr1 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;
 	}

 	saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
 	lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
 	lpr0 |= AT91_DDRSDRC_LPCB_SELF_REFRESH;

 	/* self-refresh mode now */
 	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);
 	if (at91_ramc_base[1])
 		at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);

 	cpu_do_idle();

 	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
 	if (at91_ramc_base[1])
 		at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
 }

 static void sama5d3_ddr_standby(void)
 {
 	u32 lpr0;
 	u32 saved_lpr0;

 	saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
 	lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
 	lpr0 |= AT91_DDRSDRC_LPCB_POWER_DOWN;

 	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);

 	cpu_do_idle();

 	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
 }

 /* We manage both DDRAM/SDRAM controllers, we need more than one value to
  * remember.
  */
 static void at91sam9_sdram_standby(void)
 {
 	u32 lpr0, lpr1 = 0;
 	u32 saved_lpr0, saved_lpr1 = 0;

 	if (at91_ramc_base[1]) {
 		saved_lpr1 = at91_ramc_read(1, AT91_SDRAMC_LPR);
 		lpr1 = saved_lpr1 & ~AT91_SDRAMC_LPCB;
 		lpr1 |= AT91_SDRAMC_LPCB_SELF_REFRESH;
 	}

 	saved_lpr0 = at91_ramc_read(0, AT91_SDRAMC_LPR);
 	lpr0 = saved_lpr0 & ~AT91_SDRAMC_LPCB;
 	lpr0 |= AT91_SDRAMC_LPCB_SELF_REFRESH;

 	/* self-refresh mode now */
 	at91_ramc_write(0, AT91_SDRAMC_LPR, lpr0);
 	if (at91_ramc_base[1])
 		at91_ramc_write(1, AT91_SDRAMC_LPR, lpr1);

 	cpu_do_idle();

 	at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr0);
 	if (at91_ramc_base[1])
 		at91_ramc_write(1, AT91_SDRAMC_LPR, saved_lpr1);
 }

 static const struct of_device_id const ramc_ids[] __initconst = {
 	{ .compatible = "atmel,at91rm9200-sdramc", .data = at91rm9200_standby },
 	{ .compatible = "atmel,at91sam9260-sdramc", .data = at91sam9_sdram_standby },
 	{ .compatible = "atmel,at91sam9g45-ddramc", .data = at91_ddr_standby },
 	{ .compatible = "atmel,sama5d3-ddramc", .data = sama5d3_ddr_standby },
 	{ /*sentinel*/ }
 };

 static __init void at91_dt_ramc(void)
 {
 	struct device_node *np;
 	const struct of_device_id *of_id;
 	int idx = 0;
 	const void *standby = NULL;

 	for_each_matching_node_and_match(np, ramc_ids, &of_id) {
 		at91_ramc_base[idx] = of_iomap(np, 0);
 		if (!at91_ramc_base[idx])
 			panic(pr_fmt("unable to map ramc[%d] cpu registers\n"), idx);

 		if (!standby)
 			standby = of_id->data;

 		idx++;
 	}

 	if (!idx)
 		panic(pr_fmt("unable to find compatible ram controller node in dtb\n"));

 	if (!standby) {
 		pr_warn("ramc no standby function available\n");
 		return;
 	}

 	at91_pm_set_standby(standby);
 }

 static void at91rm9200_idle(void)
 {
 	/*
 	 * Disable the processor clock.  The processor will be automatically
 	 * re-enabled by an interrupt or by a reset.
 	 */
 	writel(AT91_PMC_PCK, pmc + AT91_PMC_SCDR);
 }

 static void at91sam9_idle(void)
 {
 	writel(AT91_PMC_PCK, pmc + AT91_PMC_SCDR);
 	cpu_do_idle();
 }

 static void __init at91_pm_sram_init(void)
 {
 	struct gen_pool *sram_pool;
 	phys_addr_t sram_pbase;
 	unsigned long sram_base;
 	struct device_node *node;
 	struct platform_device *pdev = NULL;

 	for_each_compatible_node(node, NULL, "mmio-sram") {
 		pdev = of_find_device_by_node(node);
 		if (pdev) {
 			of_node_put(node);
 			break;
 		}
 	}

 	if (!pdev) {
 		pr_warn("%s: failed to find sram device!\n", __func__);
 		return;
 	}

 	sram_pool = gen_pool_get(&pdev->dev, NULL);
 	if (!sram_pool) {
 		pr_warn("%s: sram pool unavailable!\n", __func__);
 		return;
 	}

 	sram_base = gen_pool_alloc(sram_pool, at91_pm_suspend_in_sram_sz);
 	if (!sram_base) {
 		pr_warn("%s: unable to alloc sram!\n", __func__);
 		return;
 	}

 	sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base);
 	at91_suspend_sram_fn = __arm_ioremap_exec(sram_pbase,
 					at91_pm_suspend_in_sram_sz, false);
 	if (!at91_suspend_sram_fn) {
 		pr_warn("SRAM: Could not map\n");
 		return;
 	}

 	/* Copy the pm suspend handler to SRAM */
 	at91_suspend_sram_fn = fncpy(at91_suspend_sram_fn,
 			&at91_pm_suspend_in_sram, at91_pm_suspend_in_sram_sz);
 }

 static const struct of_device_id atmel_pmc_ids[] __initconst = {
 	{ .compatible = "atmel,at91rm9200-pmc"  },
 	{ .compatible = "atmel,at91sam9260-pmc" },
 	{ .compatible = "atmel,at91sam9g45-pmc" },
 	{ .compatible = "atmel,at91sam9n12-pmc" },
 	{ .compatible = "atmel,at91sam9x5-pmc" },
 	{ .compatible = "atmel,sama5d3-pmc" },
 	{ .compatible = "atmel,sama5d2-pmc" },
 	{ /* sentinel */ },
 };

 static void __init at91_pm_init(void (*pm_idle)(void))
 {
 	struct device_node *pmc_np;

 	if (at91_cpuidle_device.dev.platform_data)
 		platform_device_register(&at91_cpuidle_device);

 	pmc_np = of_find_matching_node(NULL, atmel_pmc_ids);
 	pmc = of_iomap(pmc_np, 0);
 	if (!pmc) {
 		pr_err("AT91: PM not supported, PMC not found\n");
 		return;
 	}

 	if (pm_idle)
 		arm_pm_idle = pm_idle;

 	at91_pm_sram_init();

 	if (at91_suspend_sram_fn)
 		suspend_set_ops(&at91_pm_ops);
 	else
 		pr_info("AT91: PM not supported, due to no SRAM allocated\n");
 }

 void __init at91rm9200_pm_init(void)
 {
 	at91_dt_ramc();

 	/*
 	 * AT91RM9200 SDRAM low-power mode cannot be used with self-refresh.
 	 */
 	at91_ramc_write(0, AT91_MC_SDRAMC_LPR, 0);

 	at91_pm_data.uhp_udp_mask = AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP;
 	at91_pm_data.memctrl = AT91_MEMCTRL_MC;

 	at91_pm_init(at91rm9200_idle);
 }

 void __init at91sam9260_pm_init(void)
 {
 	at91_dt_ramc();
 	at91_pm_data.memctrl = AT91_MEMCTRL_SDRAMC;
 	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP;
 	at91_pm_init(at91sam9_idle);
 }

 void __init at91sam9g45_pm_init(void)
 {
 	at91_dt_ramc();
 	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP;
 	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
 	at91_pm_init(at91sam9_idle);
 }

 void __init at91sam9x5_pm_init(void)
 {
 	at91_dt_ramc();
 	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP;
 	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
 	at91_pm_init(at91sam9_idle);
 }

 void __init sama5_pm_init(void)
 {
 	at91_dt_ramc();
 	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP;
 	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
 	at91_pm_init(NULL);
 }
	/*
	* arch/arm/mach-at91/pm.c
	* AT91 Power Management
	*
	* Copyright (C) 2005 David Brownell
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*/

	#include <linux/gpio.h>
	#include <linux/suspend.h>
	#include <linux/sched.h>
	#include <linux/proc_fs.h>
	#include <linux/genalloc.h>
	#include <linux/interrupt.h>
	#include <linux/sysfs.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/of_address.h>
	#include <linux/platform_device.h>
	#include <linux/platform_data/atmel.h>
	#include <linux/io.h>
	#include <linux/clk/at91_pmc.h>

	#include <asm/irq.h>
	#include <linux/atomic.h>
	#include <asm/mach/time.h>
	#include <asm/mach/irq.h>
	#include <asm/fncpy.h>
	#include <asm/cacheflush.h>
	#include <asm/system_misc.h>

	#include "generic.h"
	#include "pm.h"

	static void __iomem *pmc;

	/*
	* FIXME: this is needed to communicate between the pinctrl driver and
	* the PM implementation in the machine. Possibly part of the PM
	* implementation should be moved down into the pinctrl driver and get
	* called as part of the generic suspend/resume path.
	*/
	#ifdef CONFIG_PINCTRL_AT91
	extern void at91_pinctrl_gpio_suspend(void);
	extern void at91_pinctrl_gpio_resume(void);
	#endif

	static struct {
	unsigned long uhp_udp_mask;
	int memctrl;
	} at91_pm_data;

	void __iomem *at91_ramc_base[2];

	static int at91_pm_valid_state(suspend_state_t state)
	{
	switch (state) {
	case PM_SUSPEND_ON:
	case PM_SUSPEND_STANDBY:
	case PM_SUSPEND_MEM:
	return 1;

	default:
	return 0;
	}
	}


	static suspend_state_t target_state;

	/*
	* Called after processes are frozen, but before we shutdown devices.
	*/
	static int at91_pm_begin(suspend_state_t state)
	{
	target_state = state;
	return 0;
	}

	/*
	* Verify that all the clocks are correct before entering
	* slow-clock mode.
	*/
	static int at91_pm_verify_clocks(void)
	{
	unsigned long scsr;
	int i;

	scsr = readl(pmc + AT91_PMC_SCSR);

	/* USB must not be using PLLB */
	if ((scsr & at91_pm_data.uhp_udp_mask) != 0) {
	pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
	return 0;
	}

	/* PCK0..PCK3 must be disabled, or configured to use clk32k */
	for (i = 0; i < 4; i++) {
	u32 css;

	if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
	continue;
	css = readl(pmc + AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
	if (css != AT91_PMC_CSS_SLOW) {
	pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
	return 0;
	}
	}

	return 1;
	}

	/*
	* Call this from platform driver suspend() to see how deeply to suspend.
	* For example, some controllers (like OHCI) need one of the PLL clocks
	* in order to act as a wakeup source, and those are not available when
	* going into slow clock mode.
	*
	* REVISIT: generalize as clk_will_be_available(clk)? Other platforms have
	* the very same problem (but not using at91 main_clk), and it'd be better
	* to add one generic API rather than lots of platform-specific ones.
	*/
	int at91_suspend_entering_slow_clock(void)
	{
	return (target_state == PM_SUSPEND_MEM);
	}
	EXPORT_SYMBOL(at91_suspend_entering_slow_clock);

	static void (at91_suspend_sram_fn)(void __iomem pmc, void __iomem *ramc0,
	void __iomem *ramc1, int memctrl);

	extern void at91_pm_suspend_in_sram(void __iomem pmc, void __iomem ramc0,
	void __iomem *ramc1, int memctrl);
	extern u32 at91_pm_suspend_in_sram_sz;

	static void at91_pm_suspend(suspend_state_t state)
	{
	unsigned int pm_data = at91_pm_data.memctrl;

	pm_data \|= (state == PM_SUSPEND_MEM) ?
	AT91_PM_MODE(AT91_PM_SLOW_CLOCK) : 0;

	flush_cache_all();
	outer_disable();

	at91_suspend_sram_fn(pmc, at91_ramc_base[0],
	at91_ramc_base[1], pm_data);

	outer_resume();
	}

	static int at91_pm_enter(suspend_state_t state)
	{
	#ifdef CONFIG_PINCTRL_AT91
	at91_pinctrl_gpio_suspend();
	#endif
	switch (state) {
	/*
	* Suspend-to-RAM is like STANDBY plus slow clock mode, so
	* drivers must suspend more deeply, the master clock switches
	* to the clk32k and turns off the main oscillator
	*/
	case PM_SUSPEND_MEM:
	/*
	* Ensure that clocks are in a valid state.
	*/
	if (!at91_pm_verify_clocks())
	goto error;

	at91_pm_suspend(state);

	break;

	/*
	* STANDBY mode has all drivers suspended; ignores irqs not
	* marked as 'wakeup' event sources; and reduces DRAM power.
	* But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
	* nothing fancy done with main or cpu clocks.
	*/
	case PM_SUSPEND_STANDBY:
	at91_pm_suspend(state);
	break;

	case PM_SUSPEND_ON:
	cpu_do_idle();
	break;

	default:
	pr_debug("AT91: PM - bogus suspend state %d\n", state);
	goto error;
	}

	error:
	target_state = PM_SUSPEND_ON;

	#ifdef CONFIG_PINCTRL_AT91
	at91_pinctrl_gpio_resume();
	#endif
	return 0;
	}

	/*
	* Called right prior to thawing processes.
	*/
	static void at91_pm_end(void)
	{
	target_state = PM_SUSPEND_ON;
	}


	static const struct platform_suspend_ops at91_pm_ops = {
	.valid = at91_pm_valid_state,
	.begin = at91_pm_begin,
	.enter = at91_pm_enter,
	.end = at91_pm_end,
	};

	static struct platform_device at91_cpuidle_device = {
	.name = "cpuidle-at91",
	};

	static void at91_pm_set_standby(void (*at91_standby)(void))
	{
	if (at91_standby)
	at91_cpuidle_device.dev.platform_data = at91_standby;
	}

	/*
	* The AT91RM9200 goes into self-refresh mode with this command, and will
	* terminate self-refresh automatically on the next SDRAM access.
	*
	* Self-refresh mode is exited as soon as a memory access is made, but we don't
	* know for sure when that happens. However, we need to restore the low-power
	* mode if it was enabled before going idle. Restoring low-power mode while
	* still in self-refresh is "not recommended", but seems to work.
	*/
	static void at91rm9200_standby(void)
	{
	u32 lpr = at91_ramc_read(0, AT91_MC_SDRAMC_LPR);

	asm volatile(
	"b 1f\n\t"
	".align 5\n\t"
	"1: mcr p15, 0, %0, c7, c10, 4\n\t"
	" str %0, [%1, %2]\n\t"
	" str %3, [%1, %4]\n\t"
	" mcr p15, 0, %0, c7, c0, 4\n\t"
	" str %5, [%1, %2]"
	:
	: "r" (0), "r" (at91_ramc_base[0]), "r" (AT91_MC_SDRAMC_LPR),
	"r" (1), "r" (AT91_MC_SDRAMC_SRR),
	"r" (lpr));
	}

	/* We manage both DDRAM/SDRAM controllers, we need more than one value to
	* remember.
	*/
	static void at91_ddr_standby(void)
	{
	/* Those two values allow us to delay self-refresh activation
	* to the maximum. */
	u32 lpr0, lpr1 = 0;
	u32 saved_lpr0, saved_lpr1 = 0;

	if (at91_ramc_base[1]) {
	saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
	lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
	lpr1 \|= AT91_DDRSDRC_LPCB_SELF_REFRESH;
	}

	saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
	lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
	lpr0 \|= AT91_DDRSDRC_LPCB_SELF_REFRESH;

	/* self-refresh mode now */
	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);
	if (at91_ramc_base[1])
	at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);

	cpu_do_idle();

	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
	if (at91_ramc_base[1])
	at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
	}

	static void sama5d3_ddr_standby(void)
	{
	u32 lpr0;
	u32 saved_lpr0;

	saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR);
	lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB;
	lpr0 \|= AT91_DDRSDRC_LPCB_POWER_DOWN;

	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);

	cpu_do_idle();

	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
	}

	/* We manage both DDRAM/SDRAM controllers, we need more than one value to
	* remember.
	*/
	static void at91sam9_sdram_standby(void)
	{
	u32 lpr0, lpr1 = 0;
	u32 saved_lpr0, saved_lpr1 = 0;

	if (at91_ramc_base[1]) {
	saved_lpr1 = at91_ramc_read(1, AT91_SDRAMC_LPR);
	lpr1 = saved_lpr1 & ~AT91_SDRAMC_LPCB;
	lpr1 \|= AT91_SDRAMC_LPCB_SELF_REFRESH;
	}

	saved_lpr0 = at91_ramc_read(0, AT91_SDRAMC_LPR);
	lpr0 = saved_lpr0 & ~AT91_SDRAMC_LPCB;
	lpr0 \|= AT91_SDRAMC_LPCB_SELF_REFRESH;

	/* self-refresh mode now */
	at91_ramc_write(0, AT91_SDRAMC_LPR, lpr0);
	if (at91_ramc_base[1])
	at91_ramc_write(1, AT91_SDRAMC_LPR, lpr1);

	cpu_do_idle();

	at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr0);
	if (at91_ramc_base[1])
	at91_ramc_write(1, AT91_SDRAMC_LPR, saved_lpr1);
	}

	static const struct of_device_id const ramc_ids[] __initconst = {
	{ .compatible = "atmel,at91rm9200-sdramc", .data = at91rm9200_standby },
	{ .compatible = "atmel,at91sam9260-sdramc", .data = at91sam9_sdram_standby },
	{ .compatible = "atmel,at91sam9g45-ddramc", .data = at91_ddr_standby },
	{ .compatible = "atmel,sama5d3-ddramc", .data = sama5d3_ddr_standby },
	{ /sentinel/ }
	};

	static __init void at91_dt_ramc(void)
	{
	struct device_node *np;
	const struct of_device_id *of_id;
	int idx = 0;
	const void *standby = NULL;

	for_each_matching_node_and_match(np, ramc_ids, &of_id) {
	at91_ramc_base[idx] = of_iomap(np, 0);
	if (!at91_ramc_base[idx])
	panic(pr_fmt("unable to map ramc[%d] cpu registers\n"), idx);

	if (!standby)
	standby = of_id->data;

	idx++;
	}

	if (!idx)
	panic(pr_fmt("unable to find compatible ram controller node in dtb\n"));

	if (!standby) {
	pr_warn("ramc no standby function available\n");
	return;
	}

	at91_pm_set_standby(standby);
	}

	static void at91rm9200_idle(void)
	{
	/*
	* Disable the processor clock. The processor will be automatically
	* re-enabled by an interrupt or by a reset.
	*/
	writel(AT91_PMC_PCK, pmc + AT91_PMC_SCDR);
	}

	static void at91sam9_idle(void)
	{
	writel(AT91_PMC_PCK, pmc + AT91_PMC_SCDR);
	cpu_do_idle();
	}

	static void __init at91_pm_sram_init(void)
	{
	struct gen_pool *sram_pool;
	phys_addr_t sram_pbase;
	unsigned long sram_base;
	struct device_node *node;
	struct platform_device *pdev = NULL;

	for_each_compatible_node(node, NULL, "mmio-sram") {
	pdev = of_find_device_by_node(node);
	if (pdev) {
	of_node_put(node);
	break;
	}
	}

	if (!pdev) {
	pr_warn("%s: failed to find sram device!\n", __func__);
	return;
	}

	sram_pool = gen_pool_get(&pdev->dev, NULL);
	if (!sram_pool) {
	pr_warn("%s: sram pool unavailable!\n", __func__);
	return;
	}

	sram_base = gen_pool_alloc(sram_pool, at91_pm_suspend_in_sram_sz);
	if (!sram_base) {
	pr_warn("%s: unable to alloc sram!\n", __func__);
	return;
	}

	sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base);
	at91_suspend_sram_fn = __arm_ioremap_exec(sram_pbase,
	at91_pm_suspend_in_sram_sz, false);
	if (!at91_suspend_sram_fn) {
	pr_warn("SRAM: Could not map\n");
	return;
	}

	/* Copy the pm suspend handler to SRAM */
	at91_suspend_sram_fn = fncpy(at91_suspend_sram_fn,
	&at91_pm_suspend_in_sram, at91_pm_suspend_in_sram_sz);
	}

	static const struct of_device_id atmel_pmc_ids[] __initconst = {
	{ .compatible = "atmel,at91rm9200-pmc" },
	{ .compatible = "atmel,at91sam9260-pmc" },
	{ .compatible = "atmel,at91sam9g45-pmc" },
	{ .compatible = "atmel,at91sam9n12-pmc" },
	{ .compatible = "atmel,at91sam9x5-pmc" },
	{ .compatible = "atmel,sama5d3-pmc" },
	{ .compatible = "atmel,sama5d2-pmc" },
	{ /* sentinel */ },
	};

	static void __init at91_pm_init(void (*pm_idle)(void))
	{
	struct device_node *pmc_np;

	if (at91_cpuidle_device.dev.platform_data)
	platform_device_register(&at91_cpuidle_device);

	pmc_np = of_find_matching_node(NULL, atmel_pmc_ids);
	pmc = of_iomap(pmc_np, 0);
	if (!pmc) {
	pr_err("AT91: PM not supported, PMC not found\n");
	return;
	}

	if (pm_idle)
	arm_pm_idle = pm_idle;

	at91_pm_sram_init();

	if (at91_suspend_sram_fn)
	suspend_set_ops(&at91_pm_ops);
	else
	pr_info("AT91: PM not supported, due to no SRAM allocated\n");
	}

	void __init at91rm9200_pm_init(void)
	{
	at91_dt_ramc();

	/*
	* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh.
	*/
	at91_ramc_write(0, AT91_MC_SDRAMC_LPR, 0);

	at91_pm_data.uhp_udp_mask = AT91RM9200_PMC_UHP \| AT91RM9200_PMC_UDP;
	at91_pm_data.memctrl = AT91_MEMCTRL_MC;

	at91_pm_init(at91rm9200_idle);
	}

	void __init at91sam9260_pm_init(void)
	{
	at91_dt_ramc();
	at91_pm_data.memctrl = AT91_MEMCTRL_SDRAMC;
	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP \| AT91SAM926x_PMC_UDP;
	at91_pm_init(at91sam9_idle);
	}

	void __init at91sam9g45_pm_init(void)
	{
	at91_dt_ramc();
	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP;
	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
	at91_pm_init(at91sam9_idle);
	}

	void __init at91sam9x5_pm_init(void)
	{
	at91_dt_ramc();
	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP \| AT91SAM926x_PMC_UDP;
	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
	at91_pm_init(at91sam9_idle);
	}

	void __init sama5_pm_init(void)
	{
	at91_dt_ramc();
	at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP \| AT91SAM926x_PMC_UDP;
	at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR;
	at91_pm_init(NULL);
	}