drivers/soc/bcm/brcmstb/pm/pm-arm.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ARM-specific support for Broadcom STB S2/S3/S5 power management
 *
 * S2: clock gate CPUs and as many peripherals as possible
 * S3: power off all of the chip except the Always ON (AON) island; keep DDR is
 *     self-refresh
 * S5: (a.k.a. S3 cold boot) much like S3, except DDR is powered down, so we
 *     treat this mode like a soft power-off, with wakeup allowed from AON
 *
 * Copyright © 2014-2017 Broadcom
 */

#define pr_fmt(fmt) "brcmstb-pm: " fmt

#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/printk.h>
#include <linux/proc_fs.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/suspend.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/soc/brcmstb/brcmstb.h>

#include <asm/fncpy.h>
#include <asm/setup.h>
#include <asm/suspend.h>

#include "pm.h"
#include "aon_defs.h"

#define SHIMPHY_DDR_PAD_CNTRL		0x8c

/* Method #0 */
#define SHIMPHY_PAD_PLL_SEQUENCE	BIT(8)
#define SHIMPHY_PAD_GATE_PLL_S3		BIT(9)

/* Method #1 */
#define PWRDWN_SEQ_NO_SEQUENCING	0
#define PWRDWN_SEQ_HOLD_CHANNEL		1
#define	PWRDWN_SEQ_RESET_PLL		2
#define PWRDWN_SEQ_POWERDOWN_PLL	3

#define SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK	0x00f00000
#define SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT	20

#define	DDR_FORCE_CKE_RST_N		BIT(3)
#define	DDR_PHY_RST_N			BIT(2)
#define	DDR_PHY_CKE			BIT(1)

#define	DDR_PHY_NO_CHANNEL		0xffffffff

#define MAX_NUM_MEMC			3

struct brcmstb_memc {
	void __iomem *ddr_phy_base;
	void __iomem *ddr_shimphy_base;
	void __iomem *ddr_ctrl;
};

struct brcmstb_pm_control {
	void __iomem *aon_ctrl_base;
	void __iomem *aon_sram;
	struct brcmstb_memc memcs[MAX_NUM_MEMC];

	void __iomem *boot_sram;
	size_t boot_sram_len;

	bool support_warm_boot;
	size_t pll_status_offset;
	int num_memc;

	struct brcmstb_s3_params *s3_params;
	dma_addr_t s3_params_pa;
	int s3entry_method;
	u32 warm_boot_offset;
	u32 phy_a_standby_ctrl_offs;
	u32 phy_b_standby_ctrl_offs;
	bool needs_ddr_pad;
	struct platform_device *pdev;
};

enum bsp_initiate_command {
	BSP_CLOCK_STOP		= 0x00,
	BSP_GEN_RANDOM_KEY	= 0x4A,
	BSP_RESTORE_RANDOM_KEY	= 0x55,
	BSP_GEN_FIXED_KEY	= 0x63,
};

#define PM_INITIATE		0x01
#define PM_INITIATE_SUCCESS	0x00
#define PM_INITIATE_FAIL	0xfe

static struct brcmstb_pm_control ctrl;

noinline int brcmstb_pm_s3_finish(void);

static int (*brcmstb_pm_do_s2_sram)(void __iomem *aon_ctrl_base,
		void __iomem *ddr_phy_pll_status);

static int brcmstb_init_sram(struct device_node *dn)
{
	void __iomem *sram;
	struct resource res;
	int ret;

	ret = of_address_to_resource(dn, 0, &res);
	if (ret)
		return ret;

	/* Uncached, executable remapping of SRAM */
	sram = __arm_ioremap_exec(res.start, resource_size(&res), false);
	if (!sram)
		return -ENOMEM;

	ctrl.boot_sram = sram;
	ctrl.boot_sram_len = resource_size(&res);

	return 0;
}

static const struct of_device_id sram_dt_ids[] = {
	{ .compatible = "mmio-sram" },
	{ /* sentinel */ }
};

static int do_bsp_initiate_command(enum bsp_initiate_command cmd)
{
	void __iomem *base = ctrl.aon_ctrl_base;
	int ret;
	int timeo = 1000 * 1000; /* 1 second */

	writel_relaxed(0, base + AON_CTRL_PM_INITIATE);
	(void)readl_relaxed(base + AON_CTRL_PM_INITIATE);

	/* Go! */
	writel_relaxed((cmd << 1) | PM_INITIATE, base + AON_CTRL_PM_INITIATE);

	/*
	 * If firmware doesn't support the 'ack', then just assume it's done
	 * after 10ms. Note that this only works for command 0, BSP_CLOCK_STOP
	 */
	if (of_machine_is_compatible("brcm,bcm74371a0")) {
		(void)readl_relaxed(base + AON_CTRL_PM_INITIATE);
		mdelay(10);
		return 0;
	}

	for (;;) {
		ret = readl_relaxed(base + AON_CTRL_PM_INITIATE);
		if (!(ret & PM_INITIATE))
			break;
		if (timeo <= 0) {
			pr_err("error: timeout waiting for BSP (%x)\n", ret);
			break;
		}
		timeo -= 50;
		udelay(50);
	}

	return (ret & 0xff) != PM_INITIATE_SUCCESS;
}

static int brcmstb_pm_handshake(void)
{
	void __iomem *base = ctrl.aon_ctrl_base;
	u32 tmp;
	int ret;

	/* BSP power handshake, v1 */
	tmp = readl_relaxed(base + AON_CTRL_HOST_MISC_CMDS);
	tmp &= ~1UL;
	writel_relaxed(tmp, base + AON_CTRL_HOST_MISC_CMDS);
	(void)readl_relaxed(base + AON_CTRL_HOST_MISC_CMDS);

	ret = do_bsp_initiate_command(BSP_CLOCK_STOP);
	if (ret)
		pr_err("BSP handshake failed\n");

	/*
	 * HACK: BSP may have internal race on the CLOCK_STOP command.
	 * Avoid touching the BSP for a few milliseconds.
	 */
	mdelay(3);

	return ret;
}

static inline void shimphy_set(u32 value, u32 mask)
{
	int i;

	if (!ctrl.needs_ddr_pad)
		return;

	for (i = 0; i < ctrl.num_memc; i++) {
		u32 tmp;

		tmp = readl_relaxed(ctrl.memcs[i].ddr_shimphy_base +
			SHIMPHY_DDR_PAD_CNTRL);
		tmp = value | (tmp & mask);
		writel_relaxed(tmp, ctrl.memcs[i].ddr_shimphy_base +
			SHIMPHY_DDR_PAD_CNTRL);
	}
	wmb(); /* Complete sequence in order. */
}

static inline void ddr_ctrl_set(bool warmboot)
{
	int i;

	for (i = 0; i < ctrl.num_memc; i++) {
		u32 tmp;

		tmp = readl_relaxed(ctrl.memcs[i].ddr_ctrl +
				ctrl.warm_boot_offset);
		if (warmboot)
			tmp |= 1;
		else
			tmp &= ~1; /* Cold boot */
		writel_relaxed(tmp, ctrl.memcs[i].ddr_ctrl +
				ctrl.warm_boot_offset);
	}
	/* Complete sequence in order */
	wmb();
}

static inline void s3entry_method0(void)
{
	shimphy_set(SHIMPHY_PAD_GATE_PLL_S3 | SHIMPHY_PAD_PLL_SEQUENCE,
		    0xffffffff);
}

static inline void s3entry_method1(void)
{
	/*
	 * S3 Entry Sequence
	 * -----------------
	 * Step 1: SHIMPHY_ADDR_CNTL_0_DDR_PAD_CNTRL [ S3_PWRDWN_SEQ ] = 3
	 * Step 2: MEMC_DDR_0_WARM_BOOT [ WARM_BOOT ] = 1
	 */
	shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
		    SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
		    ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);

	ddr_ctrl_set(true);
}

static inline void s5entry_method1(void)
{
	int i;

	/*
	 * S5 Entry Sequence
	 * -----------------
	 * Step 1: SHIMPHY_ADDR_CNTL_0_DDR_PAD_CNTRL [ S3_PWRDWN_SEQ ] = 3
	 * Step 2: MEMC_DDR_0_WARM_BOOT [ WARM_BOOT ] = 0
	 * Step 3: DDR_PHY_CONTROL_REGS_[AB]_0_STANDBY_CONTROL[ CKE ] = 0
	 *	   DDR_PHY_CONTROL_REGS_[AB]_0_STANDBY_CONTROL[ RST_N ] = 0
	 */
	shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
		    SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
		    ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);

	ddr_ctrl_set(false);

	for (i = 0; i < ctrl.num_memc; i++) {
		u32 tmp;

		/* Step 3: Channel A (RST_N = CKE = 0) */
		tmp = readl_relaxed(ctrl.memcs[i].ddr_phy_base +
				  ctrl.phy_a_standby_ctrl_offs);
		tmp &= ~(DDR_PHY_RST_N | DDR_PHY_RST_N);
		writel_relaxed(tmp, ctrl.memcs[i].ddr_phy_base +
			     ctrl.phy_a_standby_ctrl_offs);

		/* Step 3: Channel B? */
		if (ctrl.phy_b_standby_ctrl_offs != DDR_PHY_NO_CHANNEL) {
			tmp = readl_relaxed(ctrl.memcs[i].ddr_phy_base +
					  ctrl.phy_b_standby_ctrl_offs);
			tmp &= ~(DDR_PHY_RST_N | DDR_PHY_RST_N);
			writel_relaxed(tmp, ctrl.memcs[i].ddr_phy_base +
				     ctrl.phy_b_standby_ctrl_offs);
		}
	}
	/* Must complete */
	wmb();
}

/*
 * Run a Power Management State Machine (PMSM) shutdown command and put the CPU
 * into a low-power mode
 */
static void brcmstb_do_pmsm_power_down(unsigned long base_cmd, bool onewrite)
{
	void __iomem *base = ctrl.aon_ctrl_base;

	if ((ctrl.s3entry_method == 1) && (base_cmd == PM_COLD_CONFIG))
		s5entry_method1();

	/* pm_start_pwrdn transition 0->1 */
	writel_relaxed(base_cmd, base + AON_CTRL_PM_CTRL);

	if (!onewrite) {
		(void)readl_relaxed(base + AON_CTRL_PM_CTRL);

		writel_relaxed(base_cmd | PM_PWR_DOWN, base + AON_CTRL_PM_CTRL);
		(void)readl_relaxed(base + AON_CTRL_PM_CTRL);
	}
	wfi();
}

/* Support S5 cold boot out of "poweroff" */
static void brcmstb_pm_poweroff(void)
{
	brcmstb_pm_handshake();

	/* Clear magic S3 warm-boot value */
	writel_relaxed(0, ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
	(void)readl_relaxed(ctrl.aon_sram + AON_REG_MAGIC_FLAGS);

	/* Skip wait-for-interrupt signal; just use a countdown */
	writel_relaxed(0x10, ctrl.aon_ctrl_base + AON_CTRL_PM_CPU_WAIT_COUNT);
	(void)readl_relaxed(ctrl.aon_ctrl_base + AON_CTRL_PM_CPU_WAIT_COUNT);

	if (ctrl.s3entry_method == 1) {
		shimphy_set((PWRDWN_SEQ_POWERDOWN_PLL <<
			     SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
			     ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
		ddr_ctrl_set(false);
		brcmstb_do_pmsm_power_down(M1_PM_COLD_CONFIG, true);
		return; /* We should never actually get here */
	}

	brcmstb_do_pmsm_power_down(PM_COLD_CONFIG, false);
}

static void *brcmstb_pm_copy_to_sram(void *fn, size_t len)
{
	unsigned int size = ALIGN(len, FNCPY_ALIGN);

	if (ctrl.boot_sram_len < size) {
		pr_err("standby code will not fit in SRAM\n");
		return NULL;
	}

	return fncpy(ctrl.boot_sram, fn, size);
}

/*
 * S2 suspend/resume picks up where we left off, so we must execute carefully
 * from SRAM, in order to allow DDR to come back up safely before we continue.
 */
static int brcmstb_pm_s2(void)
{
	/* A previous S3 can set a value hazardous to S2, so make sure. */
	if (ctrl.s3entry_method == 1) {
		shimphy_set((PWRDWN_SEQ_NO_SEQUENCING <<
			    SHIMPHY_PAD_S3_PWRDWN_SEQ_SHIFT),
			    ~SHIMPHY_PAD_S3_PWRDWN_SEQ_MASK);
		ddr_ctrl_set(false);
	}

	brcmstb_pm_do_s2_sram = brcmstb_pm_copy_to_sram(&brcmstb_pm_do_s2,
			brcmstb_pm_do_s2_sz);
	if (!brcmstb_pm_do_s2_sram)
		return -EINVAL;

	return brcmstb_pm_do_s2_sram(ctrl.aon_ctrl_base,
			ctrl.memcs[0].ddr_phy_base +
			ctrl.pll_status_offset);
}

/*
 * This function is called on a new stack, so don't allow inlining (which will
 * generate stack references on the old stack). It cannot be made static because
 * it is referenced from brcmstb_pm_s3()
 */
noinline int brcmstb_pm_s3_finish(void)
{
	struct brcmstb_s3_params *params = ctrl.s3_params;
	dma_addr_t params_pa = ctrl.s3_params_pa;
	phys_addr_t reentry = virt_to_phys(&cpu_resume_arm);
	enum bsp_initiate_command cmd;
	u32 flags;

	/*
	 * Clear parameter structure, but not DTU area, which has already been
	 * filled in. We know DTU is a the end, so we can just subtract its
	 * size.
	 */
	memset(params, 0, sizeof(*params) - sizeof(params->dtu));

	flags = readl_relaxed(ctrl.aon_sram + AON_REG_MAGIC_FLAGS);

	flags &= S3_BOOTLOADER_RESERVED;
	flags |= S3_FLAG_NO_MEM_VERIFY;
	flags |= S3_FLAG_LOAD_RANDKEY;

	/* Load random / fixed key */
	if (flags & S3_FLAG_LOAD_RANDKEY)
		cmd = BSP_GEN_RANDOM_KEY;
	else
		cmd = BSP_GEN_FIXED_KEY;
	if (do_bsp_initiate_command(cmd)) {
		pr_info("key loading failed\n");
		return -EIO;
	}

	params->magic = BRCMSTB_S3_MAGIC;
	params->reentry = reentry;

	/* No more writes to DRAM */
	flush_cache_all();

	flags |= BRCMSTB_S3_MAGIC_SHORT;

	writel_relaxed(flags, ctrl.aon_sram + AON_REG_MAGIC_FLAGS);
	writel_relaxed(lower_32_bits(params_pa),
		       ctrl.aon_sram + AON_REG_CONTROL_LOW);
	writel_relaxed(upper_32_bits(params_pa),
		       ctrl.aon_sram + AON_REG_CONTROL_HIGH);

	switch (ctrl.s3entry_method) {
	case 0:
		s3entry_method0();
		brcmstb_do_pmsm_power_down(PM_WARM_CONFIG, false);
		break;
	case 1:
		s3entry_method1();
		brcmstb_do_pmsm_power_down(M1_PM_WARM_CONFIG, true);
		break;
	default:
		return -EINVAL;
	}

	/* Must have been interrupted from wfi()? */
	return -EINTR;
}

static int brcmstb_pm_do_s3(unsigned long sp)
{
	unsigned long save_sp;
	int ret;

	asm volatile (
		"mov	%[save], sp\n"
		"mov	sp, %[new]\n"
		"bl	brcmstb_pm_s3_finish\n"
		"mov	%[ret], r0\n"
		"mov	%[new], sp\n"
		"mov	sp, %[save]\n"
		: [save] "=&r" (save_sp), [ret] "=&r" (ret)
		: [new] "r" (sp)
	);

	return ret;
}

static int brcmstb_pm_s3(void)
{
	void __iomem *sp = ctrl.boot_sram + ctrl.boot_sram_len;

	return cpu_suspend((unsigned long)sp, brcmstb_pm_do_s3);
}

static int brcmstb_pm_standby(bool deep_standby)
{
	int ret;

	if (brcmstb_pm_handshake())
		return -EIO;

	if (deep_standby)
		ret = brcmstb_pm_s3();
	else
		ret = brcmstb_pm_s2();
	if (ret)
		pr_err("%s: standby failed\n", __func__);

	return ret;
}

static int brcmstb_pm_enter(suspend_state_t state)
{
	int ret = -EINVAL;

	switch (state) {
	case PM_SUSPEND_STANDBY:
		ret = brcmstb_pm_standby(false);
		break;
	case PM_SUSPEND_MEM:
		ret = brcmstb_pm_standby(true);
		break;
	}

	return ret;
}

static int brcmstb_pm_valid(suspend_state_t state)
{
	switch (state) {
	case PM_SUSPEND_STANDBY:
		return true;
	case PM_SUSPEND_MEM:
		return ctrl.support_warm_boot;
	default:
		return false;
	}
}

static const struct platform_suspend_ops brcmstb_pm_ops = {
	.enter		= brcmstb_pm_enter,
	.valid		= brcmstb_pm_valid,
};

static const struct of_device_id aon_ctrl_dt_ids[] = {
	{ .compatible = "brcm,brcmstb-aon-ctrl" },
	{}
};

struct ddr_phy_ofdata {
	bool supports_warm_boot;
	size_t pll_status_offset;
	int s3entry_method;
	u32 warm_boot_offset;
	u32 phy_a_standby_ctrl_offs;
	u32 phy_b_standby_ctrl_offs;
};

static struct ddr_phy_ofdata ddr_phy_71_1 = {
	.supports_warm_boot = true,
	.pll_status_offset = 0x0c,
	.s3entry_method = 1,
	.warm_boot_offset = 0x2c,
	.phy_a_standby_ctrl_offs = 0x198,
	.phy_b_standby_ctrl_offs = DDR_PHY_NO_CHANNEL
};

static struct ddr_phy_ofdata ddr_phy_72_0 = {
	.supports_warm_boot = true,
	.pll_status_offset = 0x10,
	.s3entry_method = 1,
	.warm_boot_offset = 0x40,
	.phy_a_standby_ctrl_offs = 0x2a4,
	.phy_b_standby_ctrl_offs = 0x8a4
};

static struct ddr_phy_ofdata ddr_phy_225_1 = {
	.supports_warm_boot = false,
	.pll_status_offset = 0x4,
	.s3entry_method = 0
};

static struct ddr_phy_ofdata ddr_phy_240_1 = {
	.supports_warm_boot = true,
	.pll_status_offset = 0x4,
	.s3entry_method = 0
};

static const struct of_device_id ddr_phy_dt_ids[] = {
	{
		.compatible = "brcm,brcmstb-ddr-phy-v71.1",
		.data = &ddr_phy_71_1,
	},
	{
		.compatible = "brcm,brcmstb-ddr-phy-v72.0",
		.data = &ddr_phy_72_0,
	},
	{
		.compatible = "brcm,brcmstb-ddr-phy-v225.1",
		.data = &ddr_phy_225_1,
	},
	{
		.compatible = "brcm,brcmstb-ddr-phy-v240.1",
		.data = &ddr_phy_240_1,
	},
	{
		/* Same as v240.1, for the registers we care about */
		.compatible = "brcm,brcmstb-ddr-phy-v240.2",
		.data = &ddr_phy_240_1,
	},
	{}
};

struct ddr_seq_ofdata {
	bool needs_ddr_pad;
	u32 warm_boot_offset;
};

static const struct ddr_seq_ofdata ddr_seq_b22 = {
	.needs_ddr_pad = false,
	.warm_boot_offset = 0x2c,
};

static const struct ddr_seq_ofdata ddr_seq = {
	.needs_ddr_pad = true,
};

static const struct of_device_id ddr_shimphy_dt_ids[] = {
	{ .compatible = "brcm,brcmstb-ddr-shimphy-v1.0" },
	{}
};

static const struct of_device_id brcmstb_memc_of_match[] = {
	{
		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1",
		.data = &ddr_seq,
	},
	{
		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2",
		.data = &ddr_seq_b22,
	},
	{
		.compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3",
		.data = &ddr_seq_b22,
	},
	{
		.compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0",
		.data = &ddr_seq_b22,
	},
	{
		.compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1",
		.data = &ddr_seq_b22,
	},
	{
		.compatible = "brcm,brcmstb-memc-ddr",
		.data = &ddr_seq,
	},
	{},
};

static void __iomem *brcmstb_ioremap_match(const struct of_device_id *matches,
					   int index, const void **ofdata)
{
	struct device_node *dn;
	const struct of_device_id *match;

	dn = of_find_matching_node_and_match(NULL, matches, &match);
	if (!dn)
		return ERR_PTR(-EINVAL);

	if (ofdata)
		*ofdata = match->data;

	return of_io_request_and_map(dn, index, dn->full_name);
}

static int brcmstb_pm_panic_notify(struct notifier_block *nb,
		unsigned long action, void *data)
{
	writel_relaxed(BRCMSTB_PANIC_MAGIC, ctrl.aon_sram + AON_REG_PANIC);

	return NOTIFY_DONE;
}

static struct notifier_block brcmstb_pm_panic_nb = {
	.notifier_call = brcmstb_pm_panic_notify,
};

static int brcmstb_pm_probe(struct platform_device *pdev)
{
	const struct ddr_phy_ofdata *ddr_phy_data;
	const struct ddr_seq_ofdata *ddr_seq_data;
	const struct of_device_id *of_id = NULL;
	struct device_node *dn;
	void __iomem *base;
	int ret, i;

	/* AON ctrl registers */
	base = brcmstb_ioremap_match(aon_ctrl_dt_ids, 0, NULL);
	if (IS_ERR(base)) {
		pr_err("error mapping AON_CTRL\n");
		return PTR_ERR(base);
	}
	ctrl.aon_ctrl_base = base;

	/* AON SRAM registers */
	base = brcmstb_ioremap_match(aon_ctrl_dt_ids, 1, NULL);
	if (IS_ERR(base)) {
		/* Assume standard offset */
		ctrl.aon_sram = ctrl.aon_ctrl_base +
				     AON_CTRL_SYSTEM_DATA_RAM_OFS;
	} else {
		ctrl.aon_sram = base;
	}

	writel_relaxed(0, ctrl.aon_sram + AON_REG_PANIC);

	/* DDR PHY registers */
	base = brcmstb_ioremap_match(ddr_phy_dt_ids, 0,
				     (const void **)&ddr_phy_data);
	if (IS_ERR(base)) {
		pr_err("error mapping DDR PHY\n");
		return PTR_ERR(base);
	}
	ctrl.support_warm_boot = ddr_phy_data->supports_warm_boot;
	ctrl.pll_status_offset = ddr_phy_data->pll_status_offset;
	/* Only need DDR PHY 0 for now? */
	ctrl.memcs[0].ddr_phy_base = base;
	ctrl.s3entry_method = ddr_phy_data->s3entry_method;
	ctrl.phy_a_standby_ctrl_offs = ddr_phy_data->phy_a_standby_ctrl_offs;
	ctrl.phy_b_standby_ctrl_offs = ddr_phy_data->phy_b_standby_ctrl_offs;
	/*
	 * Slightly grosss to use the phy ver to get a memc,
	 * offset but that is the only versioned things so far
	 * we can test for.
	 */
	ctrl.warm_boot_offset = ddr_phy_data->warm_boot_offset;

	/* DDR SHIM-PHY registers */
	for_each_matching_node(dn, ddr_shimphy_dt_ids) {
		i = ctrl.num_memc;
		if (i >= MAX_NUM_MEMC) {
			pr_warn("too many MEMCs (max %d)\n", MAX_NUM_MEMC);
			break;
		}

		base = of_io_request_and_map(dn, 0, dn->full_name);
		if (IS_ERR(base)) {
			if (!ctrl.support_warm_boot)
				break;

			pr_err("error mapping DDR SHIMPHY %d\n", i);
			return PTR_ERR(base);
		}
		ctrl.memcs[i].ddr_shimphy_base = base;
		ctrl.num_memc++;
	}

	/* Sequencer DRAM Param and Control Registers */
	i = 0;
	for_each_matching_node(dn, brcmstb_memc_of_match) {
		base = of_iomap(dn, 0);
		if (!base) {
			pr_err("error mapping DDR Sequencer %d\n", i);
			return -ENOMEM;
		}

		of_id = of_match_node(brcmstb_memc_of_match, dn);
		if (!of_id) {
			iounmap(base);
			return -EINVAL;
		}

		ddr_seq_data = of_id->data;
		ctrl.needs_ddr_pad = ddr_seq_data->needs_ddr_pad;
		/* Adjust warm boot offset based on the DDR sequencer */
		if (ddr_seq_data->warm_boot_offset)
			ctrl.warm_boot_offset = ddr_seq_data->warm_boot_offset;

		ctrl.memcs[i].ddr_ctrl = base;
		i++;
	}

	pr_debug("PM: supports warm boot:%d, method:%d, wboffs:%x\n",
		ctrl.support_warm_boot, ctrl.s3entry_method,
		ctrl.warm_boot_offset);

	dn = of_find_matching_node(NULL, sram_dt_ids);
	if (!dn) {
		pr_err("SRAM not found\n");
		return -EINVAL;
	}

	ret = brcmstb_init_sram(dn);
	if (ret) {
		pr_err("error setting up SRAM for PM\n");
		return ret;
	}

	ctrl.pdev = pdev;

	ctrl.s3_params = kmalloc(sizeof(*ctrl.s3_params), GFP_KERNEL);
	if (!ctrl.s3_params)
		return -ENOMEM;
	ctrl.s3_params_pa = dma_map_single(&pdev->dev, ctrl.s3_params,
					   sizeof(*ctrl.s3_params),
					   DMA_TO_DEVICE);
	if (dma_mapping_error(&pdev->dev, ctrl.s3_params_pa)) {
		pr_err("error mapping DMA memory\n");
		ret = -ENOMEM;
		goto out;
	}

	atomic_notifier_chain_register(&panic_notifier_list,
				       &brcmstb_pm_panic_nb);

	pm_power_off = brcmstb_pm_poweroff;
	suspend_set_ops(&brcmstb_pm_ops);

	return 0;

out:
	kfree(ctrl.s3_params);

	pr_warn("PM: initialization failed with code %d\n", ret);

	return ret;
}

static struct platform_driver brcmstb_pm_driver = {
	.driver = {
		.name	= "brcmstb-pm",
		.of_match_table = aon_ctrl_dt_ids,
	},
};

static int __init brcmstb_pm_init(void)
{
	return platform_driver_probe(&brcmstb_pm_driver,
				     brcmstb_pm_probe);
}
module_init(brcmstb_pm_init);