memory: tegra: Add EMC (external memory controller) driver

Implements functionality needed to change the rate of the memory bus
clock.

Signed-off-by: Mikko Perttunen <[e-mail]>
Signed-off-by: Tomeu Vizoso <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/memory/tegra/Kconfig

···
 	help
 	  This driver supports the Memory Controller (MC) hardware found on
 	  NVIDIA Tegra SoCs.
+
+config TEGRA124_EMC
+	bool "NVIDIA Tegra124 External Memory Controller driver"
+	default y
+	depends on TEGRA_MC && ARCH_TEGRA_124_SOC
+	help
+	  This driver is for the External Memory Controller (EMC) found on
+	  Tegra124 chips. The EMC controls the external DRAM on the board.
+	  This driver is required to change memory timings / clock rate for
+	  external memory.

drivers/memory/tegra/Makefile

···
 tegra-mc-$(CONFIG_ARCH_TEGRA_124_SOC) += tegra124.o
 
 obj-$(CONFIG_TEGRA_MC) += tegra-mc.o
+
+obj-$(CONFIG_TEGRA124_EMC) += tegra124-emc.o

drivers/memory/tegra/tegra124-emc.c

···
+/*
+ * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author:
+ *	Mikko Perttunen <[e-mail]>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sort.h>
+#include <linux/string.h>
+
+#include <soc/tegra/emc.h>
+#include <soc/tegra/fuse.h>
+#include <soc/tegra/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_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				(2 << 30)
+#define DRAM_DEV_SEL_1				(1 << 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;
+};
+
+struct tegra_emc {
+	struct device *dev;
+
+	struct tegra_mc *mc;
+
+	void __iomem *regs;
+
+	enum emc_dram_type dram_type;
+	unsigned int dram_num;
+
+	struct emc_timing last_timing;
+	struct emc_timing *timings;
+	unsigned int num_timings;
+};
+
+/* 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;
+}
+
+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;
+}
+
+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);
+	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 %s: failed to read rate: %d\n",
+			node->name, 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 %s: failed to read emc burst data: %d\n",
+			node->name, 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 %s: failed to read " #prop ": %d\n", \
+			node->name, 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)
+			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" },
+	{}
+};
+
+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)) {
+			of_node_put(np);
+			continue;
+		}
+
+		return np;
+	}
+
+	return NULL;
+}
+
+static int tegra_emc_probe(struct platform_device *pdev)
+{
+	struct platform_device *mc;
+	struct device_node *np;
+	struct tegra_emc *emc;
+	struct resource *res;
+	u32 ram_code;
+	int err;
+
+	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
+	if (!emc)
+		return -ENOMEM;
+
+	emc->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	emc->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(emc->regs))
+		return PTR_ERR(emc->regs);
+
+	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
+	if (!np) {
+		dev_err(&pdev->dev, "could not get memory controller\n");
+		return -ENOENT;
+	}
+
+	mc = of_find_device_by_node(np);
+	if (!mc)
+		return -ENOENT;
+
+	of_node_put(np);
+
+	emc->mc = platform_get_drvdata(mc);
+	if (!emc->mc)
+		return -EPROBE_DEFER;
+
+	ram_code = tegra_read_ram_code();
+
+	np = tegra_emc_find_node_by_ram_code(pdev->dev.of_node, ram_code);
+	if (!np) {
+		dev_err(&pdev->dev,
+			"no memory timings for RAM code %u found in DT\n",
+			ram_code);
+		return -ENOENT;
+	}
+
+	err = tegra_emc_load_timings_from_dt(emc, np);
+
+	of_node_put(np);
+
+	if (err)
+		return err;
+
+	if (emc->num_timings == 0) {
+		dev_err(&pdev->dev,
+			"no memory timings for RAM code %u registered\n",
+			ram_code);
+		return -ENOENT;
+	}
+
+	err = emc_init(emc);
+	if (err) {
+		dev_err(&pdev->dev, "EMC initialization failed: %d\n", err);
+		return err;
+	}
+
+	platform_set_drvdata(pdev, emc);
+
+	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,
+	},
+};
+
+static int tegra_emc_init(void)
+{
+	return platform_driver_register(&tegra_emc_driver);
+}
+subsys_initcall(tegra_emc_init);

include/soc/tegra/emc.h

···
+/*
+ * Copyright (c) 2014 NVIDIA Corporation. All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef __SOC_TEGRA_EMC_H__
+#define __SOC_TEGRA_EMC_H__
+
+struct tegra_emc;
+
+int tegra_emc_prepare_timing_change(struct tegra_emc *emc,
+				    unsigned long rate);
+void tegra_emc_complete_timing_change(struct tegra_emc *emc,
+				      unsigned long rate);
+
+#endif /* __SOC_TEGRA_EMC_H__ */