linux-stable/drivers/memory/tegra/tegra124-emc.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
 *
 * Author:
 *	Mikko Perttunen <mperttunen@nvidia.com>
 */

#include <linux/clk-provider.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk/tegra.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/interconnect-provider.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/sort.h>
#include <linux/string.h>

#include <soc/tegra/fuse.h>
#include <soc/tegra/mc.h>

#include "mc.h"

#define EMC_FBIO_CFG5				0x104
#define	EMC_FBIO_CFG5_DRAM_TYPE_MASK		0x3
#define	EMC_FBIO_CFG5_DRAM_TYPE_SHIFT		0
#define EMC_FBIO_CFG5_DRAM_WIDTH_X64		BIT(4)

#define EMC_INTSTATUS				0x0
#define EMC_INTSTATUS_CLKCHANGE_COMPLETE	BIT(4)

#define EMC_CFG					0xc
#define EMC_CFG_DRAM_CLKSTOP_PD			BIT(31)
#define EMC_CFG_DRAM_CLKSTOP_SR			BIT(30)
#define EMC_CFG_DRAM_ACPD			BIT(29)
#define EMC_CFG_DYN_SREF			BIT(28)
#define EMC_CFG_PWR_MASK			((0xF << 28) | BIT(18))
#define EMC_CFG_DSR_VTTGEN_DRV_EN		BIT(18)

#define EMC_REFCTRL				0x20
#define EMC_REFCTRL_DEV_SEL_SHIFT		0
#define EMC_REFCTRL_ENABLE			BIT(31)

#define EMC_TIMING_CONTROL			0x28
#define EMC_RC					0x2c
#define EMC_RFC					0x30
#define EMC_RAS					0x34
#define EMC_RP					0x38
#define EMC_R2W					0x3c
#define EMC_W2R					0x40
#define EMC_R2P					0x44
#define EMC_W2P					0x48
#define EMC_RD_RCD				0x4c
#define EMC_WR_RCD				0x50
#define EMC_RRD					0x54
#define EMC_REXT				0x58
#define EMC_WDV					0x5c
#define EMC_QUSE				0x60
#define EMC_QRST				0x64
#define EMC_QSAFE				0x68
#define EMC_RDV					0x6c
#define EMC_REFRESH				0x70
#define EMC_BURST_REFRESH_NUM			0x74
#define EMC_PDEX2WR				0x78
#define EMC_PDEX2RD				0x7c
#define EMC_PCHG2PDEN				0x80
#define EMC_ACT2PDEN				0x84
#define EMC_AR2PDEN				0x88
#define EMC_RW2PDEN				0x8c
#define EMC_TXSR				0x90
#define EMC_TCKE				0x94
#define EMC_TFAW				0x98
#define EMC_TRPAB				0x9c
#define EMC_TCLKSTABLE				0xa0
#define EMC_TCLKSTOP				0xa4
#define EMC_TREFBW				0xa8
#define EMC_ODT_WRITE				0xb0
#define EMC_ODT_READ				0xb4
#define EMC_WEXT				0xb8
#define EMC_CTT					0xbc
#define EMC_RFC_SLR				0xc0
#define EMC_MRS_WAIT_CNT2			0xc4

#define EMC_MRS_WAIT_CNT			0xc8
#define EMC_MRS_WAIT_CNT_SHORT_WAIT_SHIFT	0
#define EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK	\
	(0x3FF << EMC_MRS_WAIT_CNT_SHORT_WAIT_SHIFT)
#define EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT	16
#define EMC_MRS_WAIT_CNT_LONG_WAIT_MASK		\
	(0x3FF << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT)

#define EMC_MRS					0xcc
#define EMC_MODE_SET_DLL_RESET			BIT(8)
#define EMC_MODE_SET_LONG_CNT			BIT(26)
#define EMC_EMRS				0xd0
#define EMC_REF					0xd4
#define EMC_PRE					0xd8

#define EMC_SELF_REF				0xe0
#define EMC_SELF_REF_CMD_ENABLED		BIT(0)
#define EMC_SELF_REF_DEV_SEL_SHIFT		30

#define EMC_MRW					0xe8

#define EMC_MRR					0xec
#define EMC_MRR_MA_SHIFT			16
#define LPDDR2_MR4_TEMP_SHIFT			0

#define EMC_XM2DQSPADCTRL3			0xf8
#define EMC_FBIO_SPARE				0x100

#define EMC_FBIO_CFG6				0x114
#define EMC_EMRS2				0x12c
#define EMC_MRW2				0x134
#define EMC_MRW4				0x13c
#define EMC_EINPUT				0x14c
#define EMC_EINPUT_DURATION			0x150
#define EMC_PUTERM_EXTRA			0x154
#define EMC_TCKESR				0x158
#define EMC_TPD					0x15c

#define EMC_AUTO_CAL_CONFIG			0x2a4
#define EMC_AUTO_CAL_CONFIG_AUTO_CAL_START	BIT(31)
#define EMC_AUTO_CAL_INTERVAL			0x2a8
#define EMC_AUTO_CAL_STATUS			0x2ac
#define EMC_AUTO_CAL_STATUS_ACTIVE		BIT(31)
#define EMC_STATUS				0x2b4
#define EMC_STATUS_TIMING_UPDATE_STALLED	BIT(23)

#define EMC_CFG_2				0x2b8
#define EMC_CFG_2_MODE_SHIFT			0
#define EMC_CFG_2_DIS_STP_OB_CLK_DURING_NON_WR	BIT(6)

#define EMC_CFG_DIG_DLL				0x2bc
#define EMC_CFG_DIG_DLL_PERIOD			0x2c0
#define EMC_RDV_MASK				0x2cc
#define EMC_WDV_MASK				0x2d0
#define EMC_CTT_DURATION			0x2d8
#define EMC_CTT_TERM_CTRL			0x2dc
#define EMC_ZCAL_INTERVAL			0x2e0
#define EMC_ZCAL_WAIT_CNT			0x2e4

#define EMC_ZQ_CAL				0x2ec
#define EMC_ZQ_CAL_CMD				BIT(0)
#define EMC_ZQ_CAL_LONG				BIT(4)
#define EMC_ZQ_CAL_LONG_CMD_DEV0		\
	(DRAM_DEV_SEL_0 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)
#define EMC_ZQ_CAL_LONG_CMD_DEV1		\
	(DRAM_DEV_SEL_1 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)

#define EMC_XM2CMDPADCTRL			0x2f0
#define EMC_XM2DQSPADCTRL			0x2f8
#define EMC_XM2DQSPADCTRL2			0x2fc
#define EMC_XM2DQSPADCTRL2_RX_FT_REC_ENABLE	BIT(0)
#define EMC_XM2DQSPADCTRL2_VREF_ENABLE		BIT(5)
#define EMC_XM2DQPADCTRL			0x300
#define EMC_XM2DQPADCTRL2			0x304
#define EMC_XM2CLKPADCTRL			0x308
#define EMC_XM2COMPPADCTRL			0x30c
#define EMC_XM2VTTGENPADCTRL			0x310
#define EMC_XM2VTTGENPADCTRL2			0x314
#define EMC_XM2VTTGENPADCTRL3			0x318
#define EMC_XM2DQSPADCTRL4			0x320
#define EMC_DLL_XFORM_DQS0			0x328
#define EMC_DLL_XFORM_DQS1			0x32c
#define EMC_DLL_XFORM_DQS2			0x330
#define EMC_DLL_XFORM_DQS3			0x334
#define EMC_DLL_XFORM_DQS4			0x338
#define EMC_DLL_XFORM_DQS5			0x33c
#define EMC_DLL_XFORM_DQS6			0x340
#define EMC_DLL_XFORM_DQS7			0x344
#define EMC_DLL_XFORM_QUSE0			0x348
#define EMC_DLL_XFORM_QUSE1			0x34c
#define EMC_DLL_XFORM_QUSE2			0x350
#define EMC_DLL_XFORM_QUSE3			0x354
#define EMC_DLL_XFORM_QUSE4			0x358
#define EMC_DLL_XFORM_QUSE5			0x35c
#define EMC_DLL_XFORM_QUSE6			0x360
#define EMC_DLL_XFORM_QUSE7			0x364
#define EMC_DLL_XFORM_DQ0			0x368
#define EMC_DLL_XFORM_DQ1			0x36c
#define EMC_DLL_XFORM_DQ2			0x370
#define EMC_DLL_XFORM_DQ3			0x374
#define EMC_DLI_TRIM_TXDQS0			0x3a8
#define EMC_DLI_TRIM_TXDQS1			0x3ac
#define EMC_DLI_TRIM_TXDQS2			0x3b0
#define EMC_DLI_TRIM_TXDQS3			0x3b4
#define EMC_DLI_TRIM_TXDQS4			0x3b8
#define EMC_DLI_TRIM_TXDQS5			0x3bc
#define EMC_DLI_TRIM_TXDQS6			0x3c0
#define EMC_DLI_TRIM_TXDQS7			0x3c4
#define EMC_STALL_THEN_EXE_AFTER_CLKCHANGE	0x3cc
#define EMC_SEL_DPD_CTRL			0x3d8
#define EMC_SEL_DPD_CTRL_DATA_SEL_DPD		BIT(8)
#define EMC_SEL_DPD_CTRL_ODT_SEL_DPD		BIT(5)
#define EMC_SEL_DPD_CTRL_RESET_SEL_DPD		BIT(4)
#define EMC_SEL_DPD_CTRL_CA_SEL_DPD		BIT(3)
#define EMC_SEL_DPD_CTRL_CLK_SEL_DPD		BIT(2)
#define EMC_SEL_DPD_CTRL_DDR3_MASK	\
	((0xf << 2) | BIT(8))
#define EMC_SEL_DPD_CTRL_MASK \
	((0x3 << 2) | BIT(5) | BIT(8))
#define EMC_PRE_REFRESH_REQ_CNT			0x3dc
#define EMC_DYN_SELF_REF_CONTROL		0x3e0
#define EMC_TXSRDLL				0x3e4
#define EMC_CCFIFO_ADDR				0x3e8
#define EMC_CCFIFO_DATA				0x3ec
#define EMC_CCFIFO_STATUS			0x3f0
#define EMC_CDB_CNTL_1				0x3f4
#define EMC_CDB_CNTL_2				0x3f8
#define EMC_XM2CLKPADCTRL2			0x3fc
#define EMC_AUTO_CAL_CONFIG2			0x458
#define EMC_AUTO_CAL_CONFIG3			0x45c
#define EMC_IBDLY				0x468
#define EMC_DLL_XFORM_ADDR0			0x46c
#define EMC_DLL_XFORM_ADDR1			0x470
#define EMC_DLL_XFORM_ADDR2			0x474
#define EMC_DSR_VTTGEN_DRV			0x47c
#define EMC_TXDSRVTTGEN				0x480
#define EMC_XM2CMDPADCTRL4			0x484
#define EMC_XM2CMDPADCTRL5			0x488
#define EMC_DLL_XFORM_DQS8			0x4a0
#define EMC_DLL_XFORM_DQS9			0x4a4
#define EMC_DLL_XFORM_DQS10			0x4a8
#define EMC_DLL_XFORM_DQS11			0x4ac
#define EMC_DLL_XFORM_DQS12			0x4b0
#define EMC_DLL_XFORM_DQS13			0x4b4
#define EMC_DLL_XFORM_DQS14			0x4b8
#define EMC_DLL_XFORM_DQS15			0x4bc
#define EMC_DLL_XFORM_QUSE8			0x4c0
#define EMC_DLL_XFORM_QUSE9			0x4c4
#define EMC_DLL_XFORM_QUSE10			0x4c8
#define EMC_DLL_XFORM_QUSE11			0x4cc
#define EMC_DLL_XFORM_QUSE12			0x4d0
#define EMC_DLL_XFORM_QUSE13			0x4d4
#define EMC_DLL_XFORM_QUSE14			0x4d8
#define EMC_DLL_XFORM_QUSE15			0x4dc
#define EMC_DLL_XFORM_DQ4			0x4e0
#define EMC_DLL_XFORM_DQ5			0x4e4
#define EMC_DLL_XFORM_DQ6			0x4e8
#define EMC_DLL_XFORM_DQ7			0x4ec
#define EMC_DLI_TRIM_TXDQS8			0x520
#define EMC_DLI_TRIM_TXDQS9			0x524
#define EMC_DLI_TRIM_TXDQS10			0x528
#define EMC_DLI_TRIM_TXDQS11			0x52c
#define EMC_DLI_TRIM_TXDQS12			0x530
#define EMC_DLI_TRIM_TXDQS13			0x534
#define EMC_DLI_TRIM_TXDQS14			0x538
#define EMC_DLI_TRIM_TXDQS15			0x53c
#define EMC_CDB_CNTL_3				0x540
#define EMC_XM2DQSPADCTRL5			0x544
#define EMC_XM2DQSPADCTRL6			0x548
#define EMC_XM2DQPADCTRL3			0x54c
#define EMC_DLL_XFORM_ADDR3			0x550
#define EMC_DLL_XFORM_ADDR4			0x554
#define EMC_DLL_XFORM_ADDR5			0x558
#define EMC_CFG_PIPE				0x560
#define EMC_QPOP				0x564
#define EMC_QUSE_WIDTH				0x568
#define EMC_PUTERM_WIDTH			0x56c
#define EMC_BGBIAS_CTL0				0x570
#define EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_RX BIT(3)
#define EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_VTTGEN BIT(2)
#define EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD	BIT(1)
#define EMC_PUTERM_ADJ				0x574

#define DRAM_DEV_SEL_ALL			0
#define DRAM_DEV_SEL_0				BIT(31)
#define DRAM_DEV_SEL_1				BIT(30)

#define EMC_CFG_POWER_FEATURES_MASK		\
	(EMC_CFG_DYN_SREF | EMC_CFG_DRAM_ACPD | EMC_CFG_DRAM_CLKSTOP_SR | \
	EMC_CFG_DRAM_CLKSTOP_PD | EMC_CFG_DSR_VTTGEN_DRV_EN)
#define EMC_REFCTRL_DEV_SEL(n) (((n > 1) ? 0 : 2) << EMC_REFCTRL_DEV_SEL_SHIFT)
#define EMC_DRAM_DEV_SEL(n) ((n > 1) ? DRAM_DEV_SEL_ALL : DRAM_DEV_SEL_0)

/* Maximum amount of time in us. to wait for changes to become effective */
#define EMC_STATUS_UPDATE_TIMEOUT		1000

enum emc_dram_type {
	DRAM_TYPE_DDR3 = 0,
	DRAM_TYPE_DDR1 = 1,
	DRAM_TYPE_LPDDR3 = 2,
	DRAM_TYPE_DDR2 = 3
};

enum emc_dll_change {
	DLL_CHANGE_NONE,
	DLL_CHANGE_ON,
	DLL_CHANGE_OFF
};

static const unsigned long emc_burst_regs[] = {
	EMC_RC,
	EMC_RFC,
	EMC_RFC_SLR,
	EMC_RAS,
	EMC_RP,
	EMC_R2W,
	EMC_W2R,
	EMC_R2P,
	EMC_W2P,
	EMC_RD_RCD,
	EMC_WR_RCD,
	EMC_RRD,
	EMC_REXT,
	EMC_WEXT,
	EMC_WDV,
	EMC_WDV_MASK,
	EMC_QUSE,
	EMC_QUSE_WIDTH,
	EMC_IBDLY,
	EMC_EINPUT,
	EMC_EINPUT_DURATION,
	EMC_PUTERM_EXTRA,
	EMC_PUTERM_WIDTH,
	EMC_PUTERM_ADJ,
	EMC_CDB_CNTL_1,
	EMC_CDB_CNTL_2,
	EMC_CDB_CNTL_3,
	EMC_QRST,
	EMC_QSAFE,
	EMC_RDV,
	EMC_RDV_MASK,
	EMC_REFRESH,
	EMC_BURST_REFRESH_NUM,
	EMC_PRE_REFRESH_REQ_CNT,
	EMC_PDEX2WR,
	EMC_PDEX2RD,
	EMC_PCHG2PDEN,
	EMC_ACT2PDEN,
	EMC_AR2PDEN,
	EMC_RW2PDEN,
	EMC_TXSR,
	EMC_TXSRDLL,
	EMC_TCKE,
	EMC_TCKESR,
	EMC_TPD,
	EMC_TFAW,
	EMC_TRPAB,
	EMC_TCLKSTABLE,
	EMC_TCLKSTOP,
	EMC_TREFBW,
	EMC_FBIO_CFG6,
	EMC_ODT_WRITE,
	EMC_ODT_READ,
	EMC_FBIO_CFG5,
	EMC_CFG_DIG_DLL,
	EMC_CFG_DIG_DLL_PERIOD,
	EMC_DLL_XFORM_DQS0,
	EMC_DLL_XFORM_DQS1,
	EMC_DLL_XFORM_DQS2,
	EMC_DLL_XFORM_DQS3,
	EMC_DLL_XFORM_DQS4,
	EMC_DLL_XFORM_DQS5,
	EMC_DLL_XFORM_DQS6,
	EMC_DLL_XFORM_DQS7,
	EMC_DLL_XFORM_DQS8,
	EMC_DLL_XFORM_DQS9,
	EMC_DLL_XFORM_DQS10,
	EMC_DLL_XFORM_DQS11,
	EMC_DLL_XFORM_DQS12,
	EMC_DLL_XFORM_DQS13,
	EMC_DLL_XFORM_DQS14,
	EMC_DLL_XFORM_DQS15,
	EMC_DLL_XFORM_QUSE0,
	EMC_DLL_XFORM_QUSE1,
	EMC_DLL_XFORM_QUSE2,
	EMC_DLL_XFORM_QUSE3,
	EMC_DLL_XFORM_QUSE4,
	EMC_DLL_XFORM_QUSE5,
	EMC_DLL_XFORM_QUSE6,
	EMC_DLL_XFORM_QUSE7,
	EMC_DLL_XFORM_ADDR0,
	EMC_DLL_XFORM_ADDR1,
	EMC_DLL_XFORM_ADDR2,
	EMC_DLL_XFORM_ADDR3,
	EMC_DLL_XFORM_ADDR4,
	EMC_DLL_XFORM_ADDR5,
	EMC_DLL_XFORM_QUSE8,
	EMC_DLL_XFORM_QUSE9,
	EMC_DLL_XFORM_QUSE10,
	EMC_DLL_XFORM_QUSE11,
	EMC_DLL_XFORM_QUSE12,
	EMC_DLL_XFORM_QUSE13,
	EMC_DLL_XFORM_QUSE14,
	EMC_DLL_XFORM_QUSE15,
	EMC_DLI_TRIM_TXDQS0,
	EMC_DLI_TRIM_TXDQS1,
	EMC_DLI_TRIM_TXDQS2,
	EMC_DLI_TRIM_TXDQS3,
	EMC_DLI_TRIM_TXDQS4,
	EMC_DLI_TRIM_TXDQS5,
	EMC_DLI_TRIM_TXDQS6,
	EMC_DLI_TRIM_TXDQS7,
	EMC_DLI_TRIM_TXDQS8,
	EMC_DLI_TRIM_TXDQS9,
	EMC_DLI_TRIM_TXDQS10,
	EMC_DLI_TRIM_TXDQS11,
	EMC_DLI_TRIM_TXDQS12,
	EMC_DLI_TRIM_TXDQS13,
	EMC_DLI_TRIM_TXDQS14,
	EMC_DLI_TRIM_TXDQS15,
	EMC_DLL_XFORM_DQ0,
	EMC_DLL_XFORM_DQ1,
	EMC_DLL_XFORM_DQ2,
	EMC_DLL_XFORM_DQ3,
	EMC_DLL_XFORM_DQ4,
	EMC_DLL_XFORM_DQ5,
	EMC_DLL_XFORM_DQ6,
	EMC_DLL_XFORM_DQ7,
	EMC_XM2CMDPADCTRL,
	EMC_XM2CMDPADCTRL4,
	EMC_XM2CMDPADCTRL5,
	EMC_XM2DQPADCTRL2,
	EMC_XM2DQPADCTRL3,
	EMC_XM2CLKPADCTRL,
	EMC_XM2CLKPADCTRL2,
	EMC_XM2COMPPADCTRL,
	EMC_XM2VTTGENPADCTRL,
	EMC_XM2VTTGENPADCTRL2,
	EMC_XM2VTTGENPADCTRL3,
	EMC_XM2DQSPADCTRL3,
	EMC_XM2DQSPADCTRL4,
	EMC_XM2DQSPADCTRL5,
	EMC_XM2DQSPADCTRL6,
	EMC_DSR_VTTGEN_DRV,
	EMC_TXDSRVTTGEN,
	EMC_FBIO_SPARE,
	EMC_ZCAL_WAIT_CNT,
	EMC_MRS_WAIT_CNT2,
	EMC_CTT,
	EMC_CTT_DURATION,
	EMC_CFG_PIPE,
	EMC_DYN_SELF_REF_CONTROL,
	EMC_QPOP
};

struct emc_timing {
	unsigned long rate;

	u32 emc_burst_data[ARRAY_SIZE(emc_burst_regs)];

	u32 emc_auto_cal_config;
	u32 emc_auto_cal_config2;
	u32 emc_auto_cal_config3;
	u32 emc_auto_cal_interval;
	u32 emc_bgbias_ctl0;
	u32 emc_cfg;
	u32 emc_cfg_2;
	u32 emc_ctt_term_ctrl;
	u32 emc_mode_1;
	u32 emc_mode_2;
	u32 emc_mode_4;
	u32 emc_mode_reset;
	u32 emc_mrs_wait_cnt;
	u32 emc_sel_dpd_ctrl;
	u32 emc_xm2dqspadctrl2;
	u32 emc_zcal_cnt_long;
	u32 emc_zcal_interval;
};

enum emc_rate_request_type {
	EMC_RATE_DEBUG,
	EMC_RATE_ICC,
	EMC_RATE_TYPE_MAX,
};

struct emc_rate_request {
	unsigned long min_rate;
	unsigned long max_rate;
};

struct tegra_emc {
	struct device *dev;

	struct tegra_mc *mc;

	void __iomem *regs;

	struct clk *clk;

	enum emc_dram_type dram_type;
	unsigned int dram_bus_width;
	unsigned int dram_num;

	struct emc_timing last_timing;
	struct emc_timing *timings;
	unsigned int num_timings;

	struct {
		struct dentry *root;
		unsigned long min_rate;
		unsigned long max_rate;
	} debugfs;

	struct icc_provider provider;

	/*
	 * There are multiple sources in the EMC driver which could request
	 * a min/max clock rate, these rates are contained in this array.
	 */
	struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];

	/* protect shared rate-change code path */
	struct mutex rate_lock;
};

/* Timing change sequence functions */

static void emc_ccfifo_writel(struct tegra_emc *emc, u32 value,
			      unsigned long offset)
{
	writel(value, emc->regs + EMC_CCFIFO_DATA);
	writel(offset, emc->regs + EMC_CCFIFO_ADDR);
}

static void emc_seq_update_timing(struct tegra_emc *emc)
{
	unsigned int i;
	u32 value;

	writel(1, emc->regs + EMC_TIMING_CONTROL);

	for (i = 0; i < EMC_STATUS_UPDATE_TIMEOUT; ++i) {
		value = readl(emc->regs + EMC_STATUS);
		if ((value & EMC_STATUS_TIMING_UPDATE_STALLED) == 0)
			return;
		udelay(1);
	}

	dev_err(emc->dev, "timing update timed out\n");
}

static void emc_seq_disable_auto_cal(struct tegra_emc *emc)
{
	unsigned int i;
	u32 value;

	writel(0, emc->regs + EMC_AUTO_CAL_INTERVAL);

	for (i = 0; i < EMC_STATUS_UPDATE_TIMEOUT; ++i) {
		value = readl(emc->regs + EMC_AUTO_CAL_STATUS);
		if ((value & EMC_AUTO_CAL_STATUS_ACTIVE) == 0)
			return;
		udelay(1);
	}

	dev_err(emc->dev, "auto cal disable timed out\n");
}

static void emc_seq_wait_clkchange(struct tegra_emc *emc)
{
	unsigned int i;
	u32 value;

	for (i = 0; i < EMC_STATUS_UPDATE_TIMEOUT; ++i) {
		value = readl(emc->regs + EMC_INTSTATUS);
		if (value & EMC_INTSTATUS_CLKCHANGE_COMPLETE)
			return;
		udelay(1);
	}

	dev_err(emc->dev, "clock change timed out\n");
}

static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc,
						unsigned long rate)
{
	struct emc_timing *timing = NULL;
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++) {
		if (emc->timings[i].rate == rate) {
			timing = &emc->timings[i];
			break;
		}
	}

	if (!timing) {
		dev_err(emc->dev, "no timing for rate %lu\n", rate);
		return NULL;
	}

	return timing;
}

static int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
					   unsigned long rate)
{
	struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
	struct emc_timing *last = &emc->last_timing;
	enum emc_dll_change dll_change;
	unsigned int pre_wait = 0;
	u32 val, val2, mask;
	bool update = false;
	unsigned int i;

	if (!timing)
		return -ENOENT;

	if ((last->emc_mode_1 & 0x1) == (timing->emc_mode_1 & 0x1))
		dll_change = DLL_CHANGE_NONE;
	else if (timing->emc_mode_1 & 0x1)
		dll_change = DLL_CHANGE_ON;
	else
		dll_change = DLL_CHANGE_OFF;

	/* Clear CLKCHANGE_COMPLETE interrupts */
	writel(EMC_INTSTATUS_CLKCHANGE_COMPLETE, emc->regs + EMC_INTSTATUS);

	/* Disable dynamic self-refresh */
	val = readl(emc->regs + EMC_CFG);
	if (val & EMC_CFG_PWR_MASK) {
		val &= ~EMC_CFG_POWER_FEATURES_MASK;
		writel(val, emc->regs + EMC_CFG);

		pre_wait = 5;
	}

	/* Disable SEL_DPD_CTRL for clock change */
	if (emc->dram_type == DRAM_TYPE_DDR3)
		mask = EMC_SEL_DPD_CTRL_DDR3_MASK;
	else
		mask = EMC_SEL_DPD_CTRL_MASK;

	val = readl(emc->regs + EMC_SEL_DPD_CTRL);
	if (val & mask) {
		val &= ~mask;
		writel(val, emc->regs + EMC_SEL_DPD_CTRL);
	}

	/* Prepare DQ/DQS for clock change */
	val = readl(emc->regs + EMC_BGBIAS_CTL0);
	val2 = last->emc_bgbias_ctl0;
	if (!(timing->emc_bgbias_ctl0 &
	      EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_RX) &&
	    (val & EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_RX)) {
		val2 &= ~EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_RX;
		update = true;
	}

	if ((val & EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD) ||
	    (val & EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_VTTGEN)) {
		update = true;
	}

	if (update) {
		writel(val2, emc->regs + EMC_BGBIAS_CTL0);
		if (pre_wait < 5)
			pre_wait = 5;
	}

	update = false;
	val = readl(emc->regs + EMC_XM2DQSPADCTRL2);
	if (timing->emc_xm2dqspadctrl2 & EMC_XM2DQSPADCTRL2_VREF_ENABLE &&
	    !(val & EMC_XM2DQSPADCTRL2_VREF_ENABLE)) {
		val |= EMC_XM2DQSPADCTRL2_VREF_ENABLE;
		update = true;
	}

	if (timing->emc_xm2dqspadctrl2 & EMC_XM2DQSPADCTRL2_RX_FT_REC_ENABLE &&
	    !(val & EMC_XM2DQSPADCTRL2_RX_FT_REC_ENABLE)) {
		val |= EMC_XM2DQSPADCTRL2_RX_FT_REC_ENABLE;
		update = true;
	}

	if (update) {
		writel(val, emc->regs + EMC_XM2DQSPADCTRL2);
		if (pre_wait < 30)
			pre_wait = 30;
	}

	/* Wait to settle */
	if (pre_wait) {
		emc_seq_update_timing(emc);
		udelay(pre_wait);
	}

	/* Program CTT_TERM control */
	if (last->emc_ctt_term_ctrl != timing->emc_ctt_term_ctrl) {
		emc_seq_disable_auto_cal(emc);
		writel(timing->emc_ctt_term_ctrl,
		       emc->regs + EMC_CTT_TERM_CTRL);
		emc_seq_update_timing(emc);
	}

	/* Program burst shadow registers */
	for (i = 0; i < ARRAY_SIZE(timing->emc_burst_data); ++i)
		writel(timing->emc_burst_data[i],
		       emc->regs + emc_burst_regs[i]);

	writel(timing->emc_xm2dqspadctrl2, emc->regs + EMC_XM2DQSPADCTRL2);
	writel(timing->emc_zcal_interval, emc->regs + EMC_ZCAL_INTERVAL);

	tegra_mc_write_emem_configuration(emc->mc, timing->rate);

	val = timing->emc_cfg & ~EMC_CFG_POWER_FEATURES_MASK;
	emc_ccfifo_writel(emc, val, EMC_CFG);

	/* Program AUTO_CAL_CONFIG */
	if (timing->emc_auto_cal_config2 != last->emc_auto_cal_config2)
		emc_ccfifo_writel(emc, timing->emc_auto_cal_config2,
				  EMC_AUTO_CAL_CONFIG2);

	if (timing->emc_auto_cal_config3 != last->emc_auto_cal_config3)
		emc_ccfifo_writel(emc, timing->emc_auto_cal_config3,
				  EMC_AUTO_CAL_CONFIG3);

	if (timing->emc_auto_cal_config != last->emc_auto_cal_config) {
		val = timing->emc_auto_cal_config;
		val &= EMC_AUTO_CAL_CONFIG_AUTO_CAL_START;
		emc_ccfifo_writel(emc, val, EMC_AUTO_CAL_CONFIG);
	}

	/* DDR3: predict MRS long wait count */
	if (emc->dram_type == DRAM_TYPE_DDR3 &&
	    dll_change == DLL_CHANGE_ON) {
		u32 cnt = 512;

		if (timing->emc_zcal_interval != 0 &&
		    last->emc_zcal_interval == 0)
			cnt -= emc->dram_num * 256;

		val = (timing->emc_mrs_wait_cnt
			& EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK)
			>> EMC_MRS_WAIT_CNT_SHORT_WAIT_SHIFT;
		if (cnt < val)
			cnt = val;

		val = timing->emc_mrs_wait_cnt
			& ~EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
		val |= (cnt << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT)
			& EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;

		writel(val, emc->regs + EMC_MRS_WAIT_CNT);
	}

	val = timing->emc_cfg_2;
	val &= ~EMC_CFG_2_DIS_STP_OB_CLK_DURING_NON_WR;
	emc_ccfifo_writel(emc, val, EMC_CFG_2);

	/* DDR3: Turn off DLL and enter self-refresh */
	if (emc->dram_type == DRAM_TYPE_DDR3 && dll_change == DLL_CHANGE_OFF)
		emc_ccfifo_writel(emc, timing->emc_mode_1, EMC_EMRS);

	/* Disable refresh controller */
	emc_ccfifo_writel(emc, EMC_REFCTRL_DEV_SEL(emc->dram_num),
			  EMC_REFCTRL);
	if (emc->dram_type == DRAM_TYPE_DDR3)
		emc_ccfifo_writel(emc, EMC_DRAM_DEV_SEL(emc->dram_num) |
				       EMC_SELF_REF_CMD_ENABLED,
				  EMC_SELF_REF);

	/* Flow control marker */
	emc_ccfifo_writel(emc, 1, EMC_STALL_THEN_EXE_AFTER_CLKCHANGE);

	/* DDR3: Exit self-refresh */
	if (emc->dram_type == DRAM_TYPE_DDR3)
		emc_ccfifo_writel(emc, EMC_DRAM_DEV_SEL(emc->dram_num),
				  EMC_SELF_REF);
	emc_ccfifo_writel(emc, EMC_REFCTRL_DEV_SEL(emc->dram_num) |
			       EMC_REFCTRL_ENABLE,
			  EMC_REFCTRL);

	/* Set DRAM mode registers */
	if (emc->dram_type == DRAM_TYPE_DDR3) {
		if (timing->emc_mode_1 != last->emc_mode_1)
			emc_ccfifo_writel(emc, timing->emc_mode_1, EMC_EMRS);
		if (timing->emc_mode_2 != last->emc_mode_2)
			emc_ccfifo_writel(emc, timing->emc_mode_2, EMC_EMRS2);

		if ((timing->emc_mode_reset != last->emc_mode_reset) ||
		    dll_change == DLL_CHANGE_ON) {
			val = timing->emc_mode_reset;
			if (dll_change == DLL_CHANGE_ON) {
				val |= EMC_MODE_SET_DLL_RESET;
				val |= EMC_MODE_SET_LONG_CNT;
			} else {
				val &= ~EMC_MODE_SET_DLL_RESET;
			}
			emc_ccfifo_writel(emc, val, EMC_MRS);
		}
	} else {
		if (timing->emc_mode_2 != last->emc_mode_2)
			emc_ccfifo_writel(emc, timing->emc_mode_2, EMC_MRW2);
		if (timing->emc_mode_1 != last->emc_mode_1)
			emc_ccfifo_writel(emc, timing->emc_mode_1, EMC_MRW);
		if (timing->emc_mode_4 != last->emc_mode_4)
			emc_ccfifo_writel(emc, timing->emc_mode_4, EMC_MRW4);
	}

	/*  Issue ZCAL command if turning ZCAL on */
	if (timing->emc_zcal_interval != 0 && last->emc_zcal_interval == 0) {
		emc_ccfifo_writel(emc, EMC_ZQ_CAL_LONG_CMD_DEV0, EMC_ZQ_CAL);
		if (emc->dram_num > 1)
			emc_ccfifo_writel(emc, EMC_ZQ_CAL_LONG_CMD_DEV1,
					  EMC_ZQ_CAL);
	}

	/*  Write to RO register to remove stall after change */
	emc_ccfifo_writel(emc, 0, EMC_CCFIFO_STATUS);

	if (timing->emc_cfg_2 & EMC_CFG_2_DIS_STP_OB_CLK_DURING_NON_WR)
		emc_ccfifo_writel(emc, timing->emc_cfg_2, EMC_CFG_2);

	/* Disable AUTO_CAL for clock change */
	emc_seq_disable_auto_cal(emc);

	/* Read register to wait until programming has settled */
	readl(emc->regs + EMC_INTSTATUS);

	return 0;
}

static void tegra_emc_complete_timing_change(struct tegra_emc *emc,
					     unsigned long rate)
{
	struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
	struct emc_timing *last = &emc->last_timing;
	u32 val;

	if (!timing)
		return;

	/* Wait until the state machine has settled */
	emc_seq_wait_clkchange(emc);

	/* Restore AUTO_CAL */
	if (timing->emc_ctt_term_ctrl != last->emc_ctt_term_ctrl)
		writel(timing->emc_auto_cal_interval,
		       emc->regs + EMC_AUTO_CAL_INTERVAL);

	/* Restore dynamic self-refresh */
	if (timing->emc_cfg & EMC_CFG_PWR_MASK)
		writel(timing->emc_cfg, emc->regs + EMC_CFG);

	/* Set ZCAL wait count */
	writel(timing->emc_zcal_cnt_long, emc->regs + EMC_ZCAL_WAIT_CNT);

	/* LPDDR3: Turn off BGBIAS if low frequency */
	if (emc->dram_type == DRAM_TYPE_LPDDR3 &&
	    timing->emc_bgbias_ctl0 &
	      EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_RX) {
		val = timing->emc_bgbias_ctl0;
		val |= EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD_IBIAS_VTTGEN;
		val |= EMC_BGBIAS_CTL0_BIAS0_DSC_E_PWRD;
		writel(val, emc->regs + EMC_BGBIAS_CTL0);
	} else {
		if (emc->dram_type == DRAM_TYPE_DDR3 &&
		    readl(emc->regs + EMC_BGBIAS_CTL0) !=
		      timing->emc_bgbias_ctl0) {
			writel(timing->emc_bgbias_ctl0,
			       emc->regs + EMC_BGBIAS_CTL0);
		}

		writel(timing->emc_auto_cal_interval,
		       emc->regs + EMC_AUTO_CAL_INTERVAL);
	}

	/* Wait for timing to settle */
	udelay(2);

	/* Reprogram SEL_DPD_CTRL */
	writel(timing->emc_sel_dpd_ctrl, emc->regs + EMC_SEL_DPD_CTRL);
	emc_seq_update_timing(emc);

	emc->last_timing = *timing;
}

/* Initialization and deinitialization */

static void emc_read_current_timing(struct tegra_emc *emc,
				    struct emc_timing *timing)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(emc_burst_regs); ++i)
		timing->emc_burst_data[i] =
			readl(emc->regs + emc_burst_regs[i]);

	timing->emc_cfg = readl(emc->regs + EMC_CFG);

	timing->emc_auto_cal_interval = 0;
	timing->emc_zcal_cnt_long = 0;
	timing->emc_mode_1 = 0;
	timing->emc_mode_2 = 0;
	timing->emc_mode_4 = 0;
	timing->emc_mode_reset = 0;
}

static int emc_init(struct tegra_emc *emc)
{
	emc->dram_type = readl(emc->regs + EMC_FBIO_CFG5);

	if (emc->dram_type & EMC_FBIO_CFG5_DRAM_WIDTH_X64)
		emc->dram_bus_width = 64;
	else
		emc->dram_bus_width = 32;

	dev_info_once(emc->dev, "%ubit DRAM bus\n", emc->dram_bus_width);

	emc->dram_type &= EMC_FBIO_CFG5_DRAM_TYPE_MASK;
	emc->dram_type >>= EMC_FBIO_CFG5_DRAM_TYPE_SHIFT;

	emc->dram_num = tegra_mc_get_emem_device_count(emc->mc);

	emc_read_current_timing(emc, &emc->last_timing);

	return 0;
}

static int load_one_timing_from_dt(struct tegra_emc *emc,
				   struct emc_timing *timing,
				   struct device_node *node)
{
	u32 value;
	int err;

	err = of_property_read_u32(node, "clock-frequency", &value);
	if (err) {
		dev_err(emc->dev, "timing %pOFn: failed to read rate: %d\n",
			node, err);
		return err;
	}

	timing->rate = value;

	err = of_property_read_u32_array(node, "nvidia,emc-configuration",
					 timing->emc_burst_data,
					 ARRAY_SIZE(timing->emc_burst_data));
	if (err) {
		dev_err(emc->dev,
			"timing %pOFn: failed to read emc burst data: %d\n",
			node, err);
		return err;
	}

#define EMC_READ_PROP(prop, dtprop) { \
	err = of_property_read_u32(node, dtprop, &timing->prop); \
	if (err) { \
		dev_err(emc->dev, "timing %pOFn: failed to read " #prop ": %d\n", \
			node, err); \
		return err; \
	} \
}

	EMC_READ_PROP(emc_auto_cal_config, "nvidia,emc-auto-cal-config")
	EMC_READ_PROP(emc_auto_cal_config2, "nvidia,emc-auto-cal-config2")
	EMC_READ_PROP(emc_auto_cal_config3, "nvidia,emc-auto-cal-config3")
	EMC_READ_PROP(emc_auto_cal_interval, "nvidia,emc-auto-cal-interval")
	EMC_READ_PROP(emc_bgbias_ctl0, "nvidia,emc-bgbias-ctl0")
	EMC_READ_PROP(emc_cfg, "nvidia,emc-cfg")
	EMC_READ_PROP(emc_cfg_2, "nvidia,emc-cfg-2")
	EMC_READ_PROP(emc_ctt_term_ctrl, "nvidia,emc-ctt-term-ctrl")
	EMC_READ_PROP(emc_mode_1, "nvidia,emc-mode-1")
	EMC_READ_PROP(emc_mode_2, "nvidia,emc-mode-2")
	EMC_READ_PROP(emc_mode_4, "nvidia,emc-mode-4")
	EMC_READ_PROP(emc_mode_reset, "nvidia,emc-mode-reset")
	EMC_READ_PROP(emc_mrs_wait_cnt, "nvidia,emc-mrs-wait-cnt")
	EMC_READ_PROP(emc_sel_dpd_ctrl, "nvidia,emc-sel-dpd-ctrl")
	EMC_READ_PROP(emc_xm2dqspadctrl2, "nvidia,emc-xm2dqspadctrl2")
	EMC_READ_PROP(emc_zcal_cnt_long, "nvidia,emc-zcal-cnt-long")
	EMC_READ_PROP(emc_zcal_interval, "nvidia,emc-zcal-interval")

#undef EMC_READ_PROP

	return 0;
}

static int cmp_timings(const void *_a, const void *_b)
{
	const struct emc_timing *a = _a;
	const struct emc_timing *b = _b;

	if (a->rate < b->rate)
		return -1;
	else if (a->rate == b->rate)
		return 0;
	else
		return 1;
}

static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc,
					  struct device_node *node)
{
	int child_count = of_get_child_count(node);
	struct device_node *child;
	struct emc_timing *timing;
	unsigned int i = 0;
	int err;

	emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
				    GFP_KERNEL);
	if (!emc->timings)
		return -ENOMEM;

	emc->num_timings = child_count;

	for_each_child_of_node(node, child) {
		timing = &emc->timings[i++];

		err = load_one_timing_from_dt(emc, timing, child);
		if (err) {
			of_node_put(child);
			return err;
		}
	}

	sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
	     NULL);

	return 0;
}

static const struct of_device_id tegra_emc_of_match[] = {
	{ .compatible = "nvidia,tegra124-emc" },
	{ .compatible = "nvidia,tegra132-emc" },
	{}
};
MODULE_DEVICE_TABLE(of, tegra_emc_of_match);

static struct device_node *
tegra_emc_find_node_by_ram_code(struct device_node *node, u32 ram_code)
{
	struct device_node *np;
	int err;

	for_each_child_of_node(node, np) {
		u32 value;

		err = of_property_read_u32(np, "nvidia,ram-code", &value);
		if (err || (value != ram_code))
			continue;

		return np;
	}

	return NULL;
}

static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
{
	unsigned int i;

	for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
		emc->requested_rate[i].min_rate = 0;
		emc->requested_rate[i].max_rate = ULONG_MAX;
	}
}

static int emc_request_rate(struct tegra_emc *emc,
			    unsigned long new_min_rate,
			    unsigned long new_max_rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = emc->requested_rate;
	unsigned long min_rate = 0, max_rate = ULONG_MAX;
	unsigned int i;
	int err;

	/* select minimum and maximum rates among the requested rates */
	for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
		if (i == type) {
			min_rate = max(new_min_rate, min_rate);
			max_rate = min(new_max_rate, max_rate);
		} else {
			min_rate = max(req->min_rate, min_rate);
			max_rate = min(req->max_rate, max_rate);
		}
	}

	if (min_rate > max_rate) {
		dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
				    __func__, type, min_rate, max_rate);
		return -ERANGE;
	}

	/*
	 * EMC rate-changes should go via OPP API because it manages voltage
	 * changes.
	 */
	err = dev_pm_opp_set_rate(emc->dev, min_rate);
	if (err)
		return err;

	emc->requested_rate[type].min_rate = new_min_rate;
	emc->requested_rate[type].max_rate = new_max_rate;

	return 0;
}

static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = &emc->requested_rate[type];
	int ret;

	mutex_lock(&emc->rate_lock);
	ret = emc_request_rate(emc, rate, req->max_rate, type);
	mutex_unlock(&emc->rate_lock);

	return ret;
}

static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = &emc->requested_rate[type];
	int ret;

	mutex_lock(&emc->rate_lock);
	ret = emc_request_rate(emc, req->min_rate, rate, type);
	mutex_unlock(&emc->rate_lock);

	return ret;
}

/*
 * debugfs interface
 *
 * The memory controller driver exposes some files in debugfs that can be used
 * to control the EMC frequency. The top-level directory can be found here:
 *
 *   /sys/kernel/debug/emc
 *
 * It contains the following files:
 *
 *   - available_rates: This file contains a list of valid, space-separated
 *     EMC frequencies.
 *
 *   - min_rate: Writing a value to this file sets the given frequency as the
 *       floor of the permitted range. If this is higher than the currently
 *       configured EMC frequency, this will cause the frequency to be
 *       increased so that it stays within the valid range.
 *
 *   - max_rate: Similarily to the min_rate file, writing a value to this file
 *       sets the given frequency as the ceiling of the permitted range. If
 *       the value is lower than the currently configured EMC frequency, this
 *       will cause the frequency to be decreased so that it stays within the
 *       valid range.
 */

static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate)
{
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++)
		if (rate == emc->timings[i].rate)
			return true;

	return false;
}

static int tegra_emc_debug_available_rates_show(struct seq_file *s,
						void *data)
{
	struct tegra_emc *emc = s->private;
	const char *prefix = "";
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++) {
		seq_printf(s, "%s%lu", prefix, emc->timings[i].rate);
		prefix = " ";
	}

	seq_puts(s, "\n");

	return 0;
}

DEFINE_SHOW_ATTRIBUTE(tegra_emc_debug_available_rates);

static int tegra_emc_debug_min_rate_get(void *data, u64 *rate)
{
	struct tegra_emc *emc = data;

	*rate = emc->debugfs.min_rate;

	return 0;
}

static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
{
	struct tegra_emc *emc = data;
	int err;

	if (!tegra_emc_validate_rate(emc, rate))
		return -EINVAL;

	err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
	if (err < 0)
		return err;

	emc->debugfs.min_rate = rate;

	return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
			tegra_emc_debug_min_rate_get,
			tegra_emc_debug_min_rate_set, "%llu\n");

static int tegra_emc_debug_max_rate_get(void *data, u64 *rate)
{
	struct tegra_emc *emc = data;

	*rate = emc->debugfs.max_rate;

	return 0;
}

static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
{
	struct tegra_emc *emc = data;
	int err;

	if (!tegra_emc_validate_rate(emc, rate))
		return -EINVAL;

	err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
	if (err < 0)
		return err;

	emc->debugfs.max_rate = rate;

	return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
			tegra_emc_debug_max_rate_get,
			tegra_emc_debug_max_rate_set, "%llu\n");

static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
{
	unsigned int i;
	int err;

	emc->debugfs.min_rate = ULONG_MAX;
	emc->debugfs.max_rate = 0;

	for (i = 0; i < emc->num_timings; i++) {
		if (emc->timings[i].rate < emc->debugfs.min_rate)
			emc->debugfs.min_rate = emc->timings[i].rate;

		if (emc->timings[i].rate > emc->debugfs.max_rate)
			emc->debugfs.max_rate = emc->timings[i].rate;
	}

	if (!emc->num_timings) {
		emc->debugfs.min_rate = clk_get_rate(emc->clk);
		emc->debugfs.max_rate = emc->debugfs.min_rate;
	}

	err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate,
				 emc->debugfs.max_rate);
	if (err < 0) {
		dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n",
			emc->debugfs.min_rate, emc->debugfs.max_rate,
			emc->clk);
		return;
	}

	emc->debugfs.root = debugfs_create_dir("emc", NULL);

	debugfs_create_file("available_rates", 0444, emc->debugfs.root, emc,
			    &tegra_emc_debug_available_rates_fops);
	debugfs_create_file("min_rate", 0644, emc->debugfs.root,
			    emc, &tegra_emc_debug_min_rate_fops);
	debugfs_create_file("max_rate", 0644, emc->debugfs.root,
			    emc, &tegra_emc_debug_max_rate_fops);
}

static inline struct tegra_emc *
to_tegra_emc_provider(struct icc_provider *provider)
{
	return container_of(provider, struct tegra_emc, provider);
}

static struct icc_node_data *
emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
{
	struct icc_provider *provider = data;
	struct icc_node_data *ndata;
	struct icc_node *node;

	/* External Memory is the only possible ICC route */
	list_for_each_entry(node, &provider->nodes, node_list) {
		if (node->id != TEGRA_ICC_EMEM)
			continue;

		ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
		if (!ndata)
			return ERR_PTR(-ENOMEM);

		/*
		 * SRC and DST nodes should have matching TAG in order to have
		 * it set by default for a requested path.
		 */
		ndata->tag = TEGRA_MC_ICC_TAG_ISO;
		ndata->node = node;

		return ndata;
	}

	return ERR_PTR(-EPROBE_DEFER);
}

static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
{
	struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
	unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
	unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
	unsigned long long rate = max(avg_bw, peak_bw);
	unsigned int dram_data_bus_width_bytes;
	const unsigned int ddr = 2;
	int err;

	/*
	 * Tegra124 EMC runs on a clock rate of SDRAM bus. This means that
	 * EMC clock rate is twice smaller than the peak data rate because
	 * data is sampled on both EMC clock edges.
	 */
	dram_data_bus_width_bytes = emc->dram_bus_width / 8;
	do_div(rate, ddr * dram_data_bus_width_bytes);
	rate = min_t(u64, rate, U32_MAX);

	err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
	if (err)
		return err;

	return 0;
}

static int tegra_emc_interconnect_init(struct tegra_emc *emc)
{
	const struct tegra_mc_soc *soc = emc->mc->soc;
	struct icc_node *node;
	int err;

	emc->provider.dev = emc->dev;
	emc->provider.set = emc_icc_set;
	emc->provider.data = &emc->provider;
	emc->provider.aggregate = soc->icc_ops->aggregate;
	emc->provider.xlate_extended = emc_of_icc_xlate_extended;

	icc_provider_init(&emc->provider);

	/* create External Memory Controller node */
	node = icc_node_create(TEGRA_ICC_EMC);
	if (IS_ERR(node)) {
		err = PTR_ERR(node);
		goto err_msg;
	}

	node->name = "External Memory Controller";
	icc_node_add(node, &emc->provider);

	/* link External Memory Controller to External Memory (DRAM) */
	err = icc_link_create(node, TEGRA_ICC_EMEM);
	if (err)
		goto remove_nodes;

	/* create External Memory node */
	node = icc_node_create(TEGRA_ICC_EMEM);
	if (IS_ERR(node)) {
		err = PTR_ERR(node);
		goto remove_nodes;
	}

	node->name = "External Memory (DRAM)";
	icc_node_add(node, &emc->provider);

	err = icc_provider_register(&emc->provider);
	if (err)
		goto remove_nodes;

	return 0;

remove_nodes:
	icc_nodes_remove(&emc->provider);
err_msg:
	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);

	return err;
}

static int tegra_emc_opp_table_init(struct tegra_emc *emc)
{
	u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
	int opp_token, err;

	err = dev_pm_opp_set_supported_hw(emc->dev, &hw_version, 1);
	if (err < 0) {
		dev_err(emc->dev, "failed to set OPP supported HW: %d\n", err);
		return err;
	}
	opp_token = err;

	err = dev_pm_opp_of_add_table(emc->dev);
	if (err) {
		if (err == -ENODEV)
			dev_err(emc->dev, "OPP table not found, please update your device tree\n");
		else
			dev_err(emc->dev, "failed to add OPP table: %d\n", err);

		goto put_hw_table;
	}

	dev_info_once(emc->dev, "OPP HW ver. 0x%x, current clock rate %lu MHz\n",
		      hw_version, clk_get_rate(emc->clk) / 1000000);

	/* first dummy rate-set initializes voltage state */
	err = dev_pm_opp_set_rate(emc->dev, clk_get_rate(emc->clk));
	if (err) {
		dev_err(emc->dev, "failed to initialize OPP clock: %d\n", err);
		goto remove_table;
	}

	return 0;

remove_table:
	dev_pm_opp_of_remove_table(emc->dev);
put_hw_table:
	dev_pm_opp_put_supported_hw(opp_token);

	return err;
}

static void devm_tegra_emc_unset_callback(void *data)
{
	tegra124_clk_set_emc_callbacks(NULL, NULL);
}

static int tegra_emc_probe(struct platform_device *pdev)
{
	struct device_node *np;
	struct tegra_emc *emc;
	u32 ram_code;
	int err;

	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
	if (!emc)
		return -ENOMEM;

	mutex_init(&emc->rate_lock);
	emc->dev = &pdev->dev;

	emc->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(emc->regs))
		return PTR_ERR(emc->regs);

	emc->mc = devm_tegra_memory_controller_get(&pdev->dev);
	if (IS_ERR(emc->mc))
		return PTR_ERR(emc->mc);

	ram_code = tegra_read_ram_code();

	np = tegra_emc_find_node_by_ram_code(pdev->dev.of_node, ram_code);
	if (np) {
		err = tegra_emc_load_timings_from_dt(emc, np);
		of_node_put(np);
		if (err)
			return err;
	} else {
		dev_info_once(&pdev->dev,
			      "no memory timings for RAM code %u found in DT\n",
			      ram_code);
	}

	err = emc_init(emc);
	if (err) {
		dev_err(&pdev->dev, "EMC initialization failed: %d\n", err);
		return err;
	}

	platform_set_drvdata(pdev, emc);

	tegra124_clk_set_emc_callbacks(tegra_emc_prepare_timing_change,
				       tegra_emc_complete_timing_change);

	err = devm_add_action_or_reset(&pdev->dev, devm_tegra_emc_unset_callback,
				       NULL);
	if (err)
		return err;

	emc->clk = devm_clk_get(&pdev->dev, "emc");
	if (IS_ERR(emc->clk)) {
		err = PTR_ERR(emc->clk);
		dev_err(&pdev->dev, "failed to get EMC clock: %d\n", err);
		return err;
	}

	err = tegra_emc_opp_table_init(emc);
	if (err)
		return err;

	tegra_emc_rate_requests_init(emc);

	if (IS_ENABLED(CONFIG_DEBUG_FS))
		emc_debugfs_init(&pdev->dev, emc);

	tegra_emc_interconnect_init(emc);

	/*
	 * Don't allow the kernel module to be unloaded. Unloading adds some
	 * extra complexity which doesn't really worth the effort in a case of
	 * this driver.
	 */
	try_module_get(THIS_MODULE);

	return 0;
};

static struct platform_driver tegra_emc_driver = {
	.probe = tegra_emc_probe,
	.driver = {
		.name = "tegra-emc",
		.of_match_table = tegra_emc_of_match,
		.suppress_bind_attrs = true,
		.sync_state = icc_sync_state,
	},
};
module_platform_driver(tegra_emc_driver);

MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA Tegra124 EMC driver");
MODULE_LICENSE("GPL v2");