memory: tegra: Introduce Tegra30 EMC driver

Introduce driver for the External Memory Controller (EMC) found on Tegra30
chips, it controls the external DRAM on the board. The purpose of this
driver is to program memory timing for external memory on the EMC clock
rate change.
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/memory/tegra/Kconfig

@@ -17,6 +17,16 @@ config TEGRA20_EMC
 	  This driver is required to change memory timings / clock rate for
 	  external memory.
 
+config TEGRA30_EMC
+	bool "NVIDIA Tegra30 External Memory Controller driver"
+	default y
+	depends on TEGRA_MC && ARCH_TEGRA_3x_SOC
+	help
+	  This driver is for the External Memory Controller (EMC) found on
+	  Tegra30 chips. The EMC controls the external DRAM on the board.
+	  This driver is required to change memory timings / clock rate for
+	  external memory.
+
 config TEGRA124_EMC
 	bool "NVIDIA Tegra124 External Memory Controller driver"
 	default y

drivers/memory/tegra/Makefile

@@ -11,5 +11,6 @@ tegra-mc-$(CONFIG_ARCH_TEGRA_210_SOC) += tegra210.o
 obj-$(CONFIG_TEGRA_MC) += tegra-mc.o
 
 obj-$(CONFIG_TEGRA20_EMC)  += tegra20-emc.o
+obj-$(CONFIG_TEGRA30_EMC)  += tegra30-emc.o
 obj-$(CONFIG_TEGRA124_EMC) += tegra124-emc.o
 obj-$(CONFIG_ARCH_TEGRA_186_SOC) += tegra186.o

drivers/memory/tegra/mc.c

@@ -49,9 +49,6 @@
 #define MC_EMEM_ADR_CFG 0x54
 #define MC_EMEM_ADR_CFG_EMEM_NUMDEV BIT(0)
 
-#define MC_TIMING_CONTROL		0xfc
-#define MC_TIMING_UPDATE		BIT(0)
-
 static const struct of_device_id tegra_mc_of_match[] = {
 #ifdef CONFIG_ARCH_TEGRA_2x_SOC
 	{ .compatible = "nvidia,tegra20-mc-gart", .data = &tegra20_mc_soc },
@@ -308,7 +305,7 @@ static int tegra_mc_setup_latency_allowance(struct tegra_mc *mc)
 	return 0;
 }
 
-void tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate)
+int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate)
 {
 	unsigned int i;
 	struct tegra_mc_timing *timing = NULL;
@@ -323,11 +320,13 @@ void tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate)
 	if (!timing) {
 		dev_err(mc->dev, "no memory timing registered for rate %lu\n",
 			rate);
-		return;
+		return -EINVAL;
 	}
 
 	for (i = 0; i < mc->soc->num_emem_regs; ++i)
 		mc_writel(mc, timing->emem_data[i], mc->soc->emem_regs[i]);
+
+	return 0;
 }
 
 unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc)

drivers/memory/tegra/mc.h

@@ -6,20 +6,32 @@
 #ifndef MEMORY_TEGRA_MC_H
 #define MEMORY_TEGRA_MC_H
 
+#include <linux/bits.h>
 #include <linux/io.h>
 #include <linux/types.h>
 
 #include <soc/tegra/mc.h>
 
-#define MC_INT_DECERR_MTS (1 << 16)
-#define MC_INT_SECERR_SEC (1 << 13)
-#define MC_INT_DECERR_VPR (1 << 12)
-#define MC_INT_INVALID_APB_ASID_UPDATE (1 << 11)
-#define MC_INT_INVALID_SMMU_PAGE (1 << 10)
-#define MC_INT_ARBITRATION_EMEM (1 << 9)
-#define MC_INT_SECURITY_VIOLATION (1 << 8)
-#define MC_INT_INVALID_GART_PAGE (1 << 7)
-#define MC_INT_DECERR_EMEM (1 << 6)
+#define MC_INT_DECERR_MTS				BIT(16)
+#define MC_INT_SECERR_SEC				BIT(13)
+#define MC_INT_DECERR_VPR				BIT(12)
+#define MC_INT_INVALID_APB_ASID_UPDATE			BIT(11)
+#define MC_INT_INVALID_SMMU_PAGE			BIT(10)
+#define MC_INT_ARBITRATION_EMEM				BIT(9)
+#define MC_INT_SECURITY_VIOLATION			BIT(8)
+#define MC_INT_INVALID_GART_PAGE			BIT(7)
+#define MC_INT_DECERR_EMEM				BIT(6)
+
+#define MC_EMEM_ARB_OUTSTANDING_REQ			0x94
+#define MC_EMEM_ARB_OUTSTANDING_REQ_MAX_MASK		0x1ff
+#define MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE	BIT(30)
+#define MC_EMEM_ARB_OUTSTANDING_REQ_LIMIT_ENABLE	BIT(31)
+
+#define MC_EMEM_ARB_OVERRIDE				0xe8
+#define MC_EMEM_ARB_OVERRIDE_EACK_MASK			0x3
+
+#define MC_TIMING_CONTROL				0xfc
+#define MC_TIMING_UPDATE				BIT(0)
 
 static inline u32 mc_readl(struct tegra_mc *mc, unsigned long offset)
 {

drivers/memory/tegra/tegra30-emc.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Tegra30 External Memory Controller driver
+ *
+ * Based on downstream driver from NVIDIA and tegra124-emc.c
+ * Copyright (C) 2011-2014 NVIDIA Corporation
+ *
+ * Author: Dmitry Osipenko <digetx@gmail.com>
+ * Copyright (C) 2019 GRATE-DRIVER project
+ */
+
+#include <linux/clk.h>
+#include <linux/clk/tegra.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sort.h>
+#include <linux/types.h>
+
+#include <soc/tegra/fuse.h>
+
+#include "mc.h"
+
+#define EMC_INTSTATUS				0x000
+#define EMC_INTMASK				0x004
+#define EMC_DBG					0x008
+#define EMC_CFG					0x00c
+#define EMC_REFCTRL				0x020
+#define EMC_TIMING_CONTROL			0x028
+#define EMC_RC					0x02c
+#define EMC_RFC					0x030
+#define EMC_RAS					0x034
+#define EMC_RP					0x038
+#define EMC_R2W					0x03c
+#define EMC_W2R					0x040
+#define EMC_R2P					0x044
+#define EMC_W2P					0x048
+#define EMC_RD_RCD				0x04c
+#define EMC_WR_RCD				0x050
+#define EMC_RRD					0x054
+#define EMC_REXT				0x058
+#define EMC_WDV					0x05c
+#define EMC_QUSE				0x060
+#define EMC_QRST				0x064
+#define EMC_QSAFE				0x068
+#define EMC_RDV					0x06c
+#define EMC_REFRESH				0x070
+#define EMC_BURST_REFRESH_NUM			0x074
+#define EMC_PDEX2WR				0x078
+#define EMC_PDEX2RD				0x07c
+#define EMC_PCHG2PDEN				0x080
+#define EMC_ACT2PDEN				0x084
+#define EMC_AR2PDEN				0x088
+#define EMC_RW2PDEN				0x08c
+#define EMC_TXSR				0x090
+#define EMC_TCKE				0x094
+#define EMC_TFAW				0x098
+#define EMC_TRPAB				0x09c
+#define EMC_TCLKSTABLE				0x0a0
+#define EMC_TCLKSTOP				0x0a4
+#define EMC_TREFBW				0x0a8
+#define EMC_QUSE_EXTRA				0x0ac
+#define EMC_ODT_WRITE				0x0b0
+#define EMC_ODT_READ				0x0b4
+#define EMC_WEXT				0x0b8
+#define EMC_CTT					0x0bc
+#define EMC_MRS_WAIT_CNT			0x0c8
+#define EMC_MRS					0x0cc
+#define EMC_EMRS				0x0d0
+#define EMC_SELF_REF				0x0e0
+#define EMC_MRW					0x0e8
+#define EMC_XM2DQSPADCTRL3			0x0f8
+#define EMC_FBIO_SPARE				0x100
+#define EMC_FBIO_CFG5				0x104
+#define EMC_FBIO_CFG6				0x114
+#define EMC_CFG_RSV				0x120
+#define EMC_AUTO_CAL_CONFIG			0x2a4
+#define EMC_AUTO_CAL_INTERVAL			0x2a8
+#define EMC_AUTO_CAL_STATUS			0x2ac
+#define EMC_STATUS				0x2b4
+#define EMC_CFG_2				0x2b8
+#define EMC_CFG_DIG_DLL				0x2bc
+#define EMC_CFG_DIG_DLL_PERIOD			0x2c0
+#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_XM2CMDPADCTRL			0x2f0
+#define EMC_XM2DQSPADCTRL2			0x2fc
+#define EMC_XM2DQPADCTRL2			0x304
+#define EMC_XM2CLKPADCTRL			0x308
+#define EMC_XM2COMPPADCTRL			0x30c
+#define EMC_XM2VTTGENPADCTRL			0x310
+#define EMC_XM2VTTGENPADCTRL2			0x314
+#define EMC_XM2QUSEPADCTRL			0x318
+#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_BEFORE_CLKCHANGE	0x3c8
+#define EMC_STALL_THEN_EXE_AFTER_CLKCHANGE	0x3cc
+#define EMC_UNSTALL_RW_AFTER_CLKCHANGE		0x3d0
+#define EMC_SEL_DPD_CTRL			0x3d8
+#define EMC_PRE_REFRESH_REQ_CNT			0x3dc
+#define EMC_DYN_SELF_REF_CONTROL		0x3e0
+#define EMC_TXSRDLL				0x3e4
+
+#define EMC_STATUS_TIMING_UPDATE_STALLED	BIT(23)
+
+#define EMC_MODE_SET_DLL_RESET			BIT(8)
+#define EMC_MODE_SET_LONG_CNT			BIT(26)
+
+#define EMC_SELF_REF_CMD_ENABLED		BIT(0)
+
+#define DRAM_DEV_SEL_ALL			(0 << 30)
+#define DRAM_DEV_SEL_0				(2 << 30)
+#define DRAM_DEV_SEL_1				(1 << 30)
+#define DRAM_BROADCAST(num) \
+	((num) > 1 ? DRAM_DEV_SEL_ALL : DRAM_DEV_SEL_0)
+
+#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_DBG_READ_MUX_ASSEMBLY		BIT(0)
+#define EMC_DBG_WRITE_MUX_ACTIVE		BIT(1)
+#define EMC_DBG_FORCE_UPDATE			BIT(2)
+#define EMC_DBG_CFG_PRIORITY			BIT(24)
+
+#define EMC_CFG5_QUSE_MODE_SHIFT		13
+#define EMC_CFG5_QUSE_MODE_MASK			(7 << EMC_CFG5_QUSE_MODE_SHIFT)
+
+#define EMC_CFG5_QUSE_MODE_INTERNAL_LPBK	2
+#define EMC_CFG5_QUSE_MODE_PULSE_INTERN		3
+
+#define EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE	BIT(9)
+
+#define EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE	BIT(10)
+
+#define EMC_XM2QUSEPADCTRL_IVREF_ENABLE		BIT(4)
+
+#define EMC_XM2DQSPADCTRL2_VREF_ENABLE		BIT(5)
+#define EMC_XM2DQSPADCTRL3_VREF_ENABLE		BIT(5)
+
+#define EMC_AUTO_CAL_STATUS_ACTIVE		BIT(31)
+
+#define	EMC_FBIO_CFG5_DRAM_TYPE_MASK		0x3
+
+#define EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK	0x3ff
+#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_REFCTRL_DEV_SEL_MASK		0x3
+#define EMC_REFCTRL_ENABLE			BIT(31)
+#define EMC_REFCTRL_ENABLE_ALL(num) \
+	(((num) > 1 ? 0 : 2) | EMC_REFCTRL_ENABLE)
+#define EMC_REFCTRL_DISABLE_ALL(num)		((num) > 1 ? 0 : 2)
+
+#define EMC_CFG_PERIODIC_QRST			BIT(21)
+#define EMC_CFG_DYN_SREF_ENABLE			BIT(28)
+
+#define EMC_CLKCHANGE_REQ_ENABLE		BIT(0)
+#define EMC_CLKCHANGE_PD_ENABLE			BIT(1)
+#define EMC_CLKCHANGE_SR_ENABLE			BIT(2)
+
+#define EMC_TIMING_UPDATE			BIT(0)
+
+#define EMC_REFRESH_OVERFLOW_INT		BIT(3)
+#define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
+
+enum emc_dram_type {
+	DRAM_TYPE_DDR3,
+	DRAM_TYPE_DDR1,
+	DRAM_TYPE_LPDDR2,
+	DRAM_TYPE_DDR2,
+};
+
+enum emc_dll_change {
+	DLL_CHANGE_NONE,
+	DLL_CHANGE_ON,
+	DLL_CHANGE_OFF
+};
+
+static const u16 emc_timing_registers[] = {
+	[0] = EMC_RC,
+	[1] = EMC_RFC,
+	[2] = EMC_RAS,
+	[3] = EMC_RP,
+	[4] = EMC_R2W,
+	[5] = EMC_W2R,
+	[6] = EMC_R2P,
+	[7] = EMC_W2P,
+	[8] = EMC_RD_RCD,
+	[9] = EMC_WR_RCD,
+	[10] = EMC_RRD,
+	[11] = EMC_REXT,
+	[12] = EMC_WEXT,
+	[13] = EMC_WDV,
+	[14] = EMC_QUSE,
+	[15] = EMC_QRST,
+	[16] = EMC_QSAFE,
+	[17] = EMC_RDV,
+	[18] = EMC_REFRESH,
+	[19] = EMC_BURST_REFRESH_NUM,
+	[20] = EMC_PRE_REFRESH_REQ_CNT,
+	[21] = EMC_PDEX2WR,
+	[22] = EMC_PDEX2RD,
+	[23] = EMC_PCHG2PDEN,
+	[24] = EMC_ACT2PDEN,
+	[25] = EMC_AR2PDEN,
+	[26] = EMC_RW2PDEN,
+	[27] = EMC_TXSR,
+	[28] = EMC_TXSRDLL,
+	[29] = EMC_TCKE,
+	[30] = EMC_TFAW,
+	[31] = EMC_TRPAB,
+	[32] = EMC_TCLKSTABLE,
+	[33] = EMC_TCLKSTOP,
+	[34] = EMC_TREFBW,
+	[35] = EMC_QUSE_EXTRA,
+	[36] = EMC_FBIO_CFG6,
+	[37] = EMC_ODT_WRITE,
+	[38] = EMC_ODT_READ,
+	[39] = EMC_FBIO_CFG5,
+	[40] = EMC_CFG_DIG_DLL,
+	[41] = EMC_CFG_DIG_DLL_PERIOD,
+	[42] = EMC_DLL_XFORM_DQS0,
+	[43] = EMC_DLL_XFORM_DQS1,
+	[44] = EMC_DLL_XFORM_DQS2,
+	[45] = EMC_DLL_XFORM_DQS3,
+	[46] = EMC_DLL_XFORM_DQS4,
+	[47] = EMC_DLL_XFORM_DQS5,
+	[48] = EMC_DLL_XFORM_DQS6,
+	[49] = EMC_DLL_XFORM_DQS7,
+	[50] = EMC_DLL_XFORM_QUSE0,
+	[51] = EMC_DLL_XFORM_QUSE1,
+	[52] = EMC_DLL_XFORM_QUSE2,
+	[53] = EMC_DLL_XFORM_QUSE3,
+	[54] = EMC_DLL_XFORM_QUSE4,
+	[55] = EMC_DLL_XFORM_QUSE5,
+	[56] = EMC_DLL_XFORM_QUSE6,
+	[57] = EMC_DLL_XFORM_QUSE7,
+	[58] = EMC_DLI_TRIM_TXDQS0,
+	[59] = EMC_DLI_TRIM_TXDQS1,
+	[60] = EMC_DLI_TRIM_TXDQS2,
+	[61] = EMC_DLI_TRIM_TXDQS3,
+	[62] = EMC_DLI_TRIM_TXDQS4,
+	[63] = EMC_DLI_TRIM_TXDQS5,
+	[64] = EMC_DLI_TRIM_TXDQS6,
+	[65] = EMC_DLI_TRIM_TXDQS7,
+	[66] = EMC_DLL_XFORM_DQ0,
+	[67] = EMC_DLL_XFORM_DQ1,
+	[68] = EMC_DLL_XFORM_DQ2,
+	[69] = EMC_DLL_XFORM_DQ3,
+	[70] = EMC_XM2CMDPADCTRL,
+	[71] = EMC_XM2DQSPADCTRL2,
+	[72] = EMC_XM2DQPADCTRL2,
+	[73] = EMC_XM2CLKPADCTRL,
+	[74] = EMC_XM2COMPPADCTRL,
+	[75] = EMC_XM2VTTGENPADCTRL,
+	[76] = EMC_XM2VTTGENPADCTRL2,
+	[77] = EMC_XM2QUSEPADCTRL,
+	[78] = EMC_XM2DQSPADCTRL3,
+	[79] = EMC_CTT_TERM_CTRL,
+	[80] = EMC_ZCAL_INTERVAL,
+	[81] = EMC_ZCAL_WAIT_CNT,
+	[82] = EMC_MRS_WAIT_CNT,
+	[83] = EMC_AUTO_CAL_CONFIG,
+	[84] = EMC_CTT,
+	[85] = EMC_CTT_DURATION,
+	[86] = EMC_DYN_SELF_REF_CONTROL,
+	[87] = EMC_FBIO_SPARE,
+	[88] = EMC_CFG_RSV,
+};
+
+struct emc_timing {
+	unsigned long rate;
+
+	u32 data[ARRAY_SIZE(emc_timing_registers)];
+
+	u32 emc_auto_cal_interval;
+	u32 emc_mode_1;
+	u32 emc_mode_2;
+	u32 emc_mode_reset;
+	u32 emc_zcal_cnt_long;
+	bool emc_cfg_periodic_qrst;
+	bool emc_cfg_dyn_self_ref;
+};
+
+struct tegra_emc {
+	struct device *dev;
+	struct tegra_mc *mc;
+	struct completion clk_handshake_complete;
+	struct notifier_block clk_nb;
+	struct clk *clk;
+	void __iomem *regs;
+	unsigned int irq;
+
+	struct emc_timing *timings;
+	unsigned int num_timings;
+
+	u32 mc_override;
+	u32 emc_cfg;
+
+	u32 emc_mode_1;
+	u32 emc_mode_2;
+	u32 emc_mode_reset;
+
+	bool vref_cal_toggle : 1;
+	bool zcal_long : 1;
+	bool dll_on : 1;
+	bool prepared : 1;
+	bool bad_state : 1;
+};
+
+static irqreturn_t tegra_emc_isr(int irq, void *data)
+{
+	struct tegra_emc *emc = data;
+	u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
+	u32 status;
+
+	status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
+	if (!status)
+		return IRQ_NONE;
+
+	/* notify about EMC-CAR handshake completion */
+	if (status & EMC_CLKCHANGE_COMPLETE_INT)
+		complete(&emc->clk_handshake_complete);
+
+	/* notify about HW problem */
+	if (status & EMC_REFRESH_OVERFLOW_INT)
+		dev_err_ratelimited(emc->dev,
+				    "refresh request overflow timeout\n");
+
+	/* clear interrupts */
+	writel_relaxed(status, emc->regs + EMC_INTSTATUS);
+
+	return IRQ_HANDLED;
+}
+
+static struct emc_timing *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 bool emc_dqs_preset(struct tegra_emc *emc, struct emc_timing *timing,
+			   bool *schmitt_to_vref)
+{
+	bool preset = false;
+	u32 val;
+
+	if (timing->data[71] & EMC_XM2DQSPADCTRL2_VREF_ENABLE) {
+		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL2);
+
+		if (!(val & EMC_XM2DQSPADCTRL2_VREF_ENABLE)) {
+			val |= EMC_XM2DQSPADCTRL2_VREF_ENABLE;
+			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL2);
+
+			preset = true;
+		}
+	}
+
+	if (timing->data[78] & EMC_XM2DQSPADCTRL3_VREF_ENABLE) {
+		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL3);
+
+		if (!(val & EMC_XM2DQSPADCTRL3_VREF_ENABLE)) {
+			val |= EMC_XM2DQSPADCTRL3_VREF_ENABLE;
+			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL3);
+
+			preset = true;
+		}
+	}
+
+	if (timing->data[77] & EMC_XM2QUSEPADCTRL_IVREF_ENABLE) {
+		val = readl_relaxed(emc->regs + EMC_XM2QUSEPADCTRL);
+
+		if (!(val & EMC_XM2QUSEPADCTRL_IVREF_ENABLE)) {
+			val |= EMC_XM2QUSEPADCTRL_IVREF_ENABLE;
+			writel_relaxed(val, emc->regs + EMC_XM2QUSEPADCTRL);
+
+			*schmitt_to_vref = true;
+			preset = true;
+		}
+	}
+
+	return preset;
+}
+
+static int emc_seq_update_timing(struct tegra_emc *emc)
+{
+	u32 val;
+	int err;
+
+	writel_relaxed(EMC_TIMING_UPDATE, emc->regs + EMC_TIMING_CONTROL);
+
+	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_STATUS, val,
+				!(val & EMC_STATUS_TIMING_UPDATE_STALLED),
+				1, 200);
+	if (err) {
+		dev_err(emc->dev, "failed to update timing: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int emc_prepare_mc_clk_cfg(struct tegra_emc *emc, unsigned long rate)
+{
+	struct tegra_mc *mc = emc->mc;
+	unsigned int misc0_index = 16;
+	unsigned int i;
+	bool same;
+
+	for (i = 0; i < mc->num_timings; i++) {
+		if (mc->timings[i].rate != rate)
+			continue;
+
+		if (mc->timings[i].emem_data[misc0_index] & BIT(27))
+			same = true;
+		else
+			same = false;
+
+		return tegra20_clk_prepare_emc_mc_same_freq(emc->clk, same);
+	}
+
+	return -EINVAL;
+}
+
+static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
+{
+	struct emc_timing *timing = emc_find_timing(emc, rate);
+	enum emc_dll_change dll_change;
+	enum emc_dram_type dram_type;
+	bool schmitt_to_vref = false;
+	unsigned int pre_wait = 0;
+	bool qrst_used = false;
+	unsigned int dram_num;
+	unsigned int i;
+	u32 fbio_cfg5;
+	u32 emc_dbg;
+	u32 val;
+	int err;
+
+	if (!timing || emc->bad_state)
+		return -EINVAL;
+
+	dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
+		__func__, timing->rate, rate);
+
+	emc->bad_state = true;
+
+	err = emc_prepare_mc_clk_cfg(emc, rate);
+	if (err) {
+		dev_err(emc->dev, "mc clock preparation failed: %d\n", err);
+		return err;
+	}
+
+	emc->vref_cal_toggle = false;
+	emc->mc_override = mc_readl(emc->mc, MC_EMEM_ARB_OVERRIDE);
+	emc->emc_cfg = readl_relaxed(emc->regs + EMC_CFG);
+	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
+
+	if (emc->dll_on == !!(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;
+
+	emc->dll_on = !!(timing->emc_mode_1 & 0x1);
+
+	if (timing->data[80] && !readl_relaxed(emc->regs + EMC_ZCAL_INTERVAL))
+		emc->zcal_long = true;
+	else
+		emc->zcal_long = false;
+
+	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
+	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
+
+	dram_num = tegra_mc_get_emem_device_count(emc->mc);
+
+	/* disable dynamic self-refresh */
+	if (emc->emc_cfg & EMC_CFG_DYN_SREF_ENABLE) {
+		emc->emc_cfg &= ~EMC_CFG_DYN_SREF_ENABLE;
+		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
+
+		pre_wait = 5;
+	}
+
+	/* update MC arbiter settings */
+	val = mc_readl(emc->mc, MC_EMEM_ARB_OUTSTANDING_REQ);
+	if (!(val & MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE) ||
+	    ((val & MC_EMEM_ARB_OUTSTANDING_REQ_MAX_MASK) > 0x50)) {
+
+		val = MC_EMEM_ARB_OUTSTANDING_REQ_LIMIT_ENABLE |
+		      MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE | 0x50;
+		mc_writel(emc->mc, val, MC_EMEM_ARB_OUTSTANDING_REQ);
+		mc_writel(emc->mc, MC_TIMING_UPDATE, MC_TIMING_CONTROL);
+	}
+
+	if (emc->mc_override & MC_EMEM_ARB_OVERRIDE_EACK_MASK)
+		mc_writel(emc->mc,
+			  emc->mc_override & ~MC_EMEM_ARB_OVERRIDE_EACK_MASK,
+			  MC_EMEM_ARB_OVERRIDE);
+
+	/* check DQ/DQS VREF delay */
+	if (emc_dqs_preset(emc, timing, &schmitt_to_vref)) {
+		if (pre_wait < 3)
+			pre_wait = 3;
+	}
+
+	if (pre_wait) {
+		err = emc_seq_update_timing(emc);
+		if (err)
+			return err;
+
+		udelay(pre_wait);
+	}
+
+	/* disable auto-calibration if VREF mode is switching */
+	if (timing->emc_auto_cal_interval) {
+		val = readl_relaxed(emc->regs + EMC_XM2COMPPADCTRL);
+		val ^= timing->data[74];
+
+		if (val & EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE) {
+			writel_relaxed(0, emc->regs + EMC_AUTO_CAL_INTERVAL);
+
+			err = readl_relaxed_poll_timeout_atomic(
+				emc->regs + EMC_AUTO_CAL_STATUS, val,
+				!(val & EMC_AUTO_CAL_STATUS_ACTIVE), 1, 300);
+			if (err) {
+				dev_err(emc->dev,
+					"failed to disable auto-cal: %d\n",
+					err);
+				return err;
+			}
+
+			emc->vref_cal_toggle = true;
+		}
+	}
+
+	/* program shadow registers */
+	for (i = 0; i < ARRAY_SIZE(timing->data); i++) {
+		/* EMC_XM2CLKPADCTRL should be programmed separately */
+		if (i != 73)
+			writel_relaxed(timing->data[i],
+				       emc->regs + emc_timing_registers[i]);
+	}
+
+	err = tegra_mc_write_emem_configuration(emc->mc, timing->rate);
+	if (err)
+		return err;
+
+	/* DDR3: predict MRS long wait count */
+	if (dram_type == DRAM_TYPE_DDR3 && dll_change == DLL_CHANGE_ON) {
+		u32 cnt = 512;
+
+		if (emc->zcal_long)
+			cnt -= dram_num * 256;
+
+		val = timing->data[82] & EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK;
+		if (cnt < val)
+			cnt = val;
+
+		val = timing->data[82] & ~EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
+		val |= (cnt << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT) &
+			EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
+
+		writel_relaxed(val, emc->regs + EMC_MRS_WAIT_CNT);
+	}
+
+	/* disable interrupt since read access is prohibited after stalling */
+	disable_irq(emc->irq);
+
+	/* this read also completes the writes */
+	val = readl_relaxed(emc->regs + EMC_SEL_DPD_CTRL);
+
+	if (!(val & EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE) && schmitt_to_vref) {
+		u32 cur_mode, new_mode;
+
+		cur_mode = fbio_cfg5 & EMC_CFG5_QUSE_MODE_MASK;
+		cur_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
+
+		new_mode = timing->data[39] & EMC_CFG5_QUSE_MODE_MASK;
+		new_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
+
+		if ((cur_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
+		     cur_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK) ||
+		    (new_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
+		     new_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK))
+			qrst_used = true;
+	}
+
+	/* flow control marker 1 */
+	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_BEFORE_CLKCHANGE);
+
+	/* enable periodic reset */
+	if (qrst_used) {
+		writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE,
+			       emc->regs + EMC_DBG);
+		writel_relaxed(emc->emc_cfg | EMC_CFG_PERIODIC_QRST,
+			       emc->regs + EMC_CFG);
+		writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
+	}
+
+	/* disable auto-refresh to save time after clock change */
+	writel_relaxed(EMC_REFCTRL_DISABLE_ALL(dram_num),
+		       emc->regs + EMC_REFCTRL);
+
+	/* turn off DLL and enter self-refresh on DDR3 */
+	if (dram_type == DRAM_TYPE_DDR3) {
+		if (dll_change == DLL_CHANGE_OFF)
+			writel_relaxed(timing->emc_mode_1,
+				       emc->regs + EMC_EMRS);
+
+		writel_relaxed(DRAM_BROADCAST(dram_num) |
+			       EMC_SELF_REF_CMD_ENABLED,
+			       emc->regs + EMC_SELF_REF);
+	}
+
+	/* flow control marker 2 */
+	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_AFTER_CLKCHANGE);
+
+	/* enable write-active MUX, update unshadowed pad control */
+	writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE, emc->regs + EMC_DBG);
+	writel_relaxed(timing->data[73], emc->regs + EMC_XM2CLKPADCTRL);
+
+	/* restore periodic QRST and disable write-active MUX */
+	val = !!(emc->emc_cfg & EMC_CFG_PERIODIC_QRST);
+	if (qrst_used || timing->emc_cfg_periodic_qrst != val) {
+		if (timing->emc_cfg_periodic_qrst)
+			emc->emc_cfg |= EMC_CFG_PERIODIC_QRST;
+		else
+			emc->emc_cfg &= ~EMC_CFG_PERIODIC_QRST;
+
+		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
+	}
+	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
+
+	/* exit self-refresh on DDR3 */
+	if (dram_type == DRAM_TYPE_DDR3)
+		writel_relaxed(DRAM_BROADCAST(dram_num),
+			       emc->regs + EMC_SELF_REF);
+
+	/* set DRAM-mode registers */
+	if (dram_type == DRAM_TYPE_DDR3) {
+		if (timing->emc_mode_1 != emc->emc_mode_1)
+			writel_relaxed(timing->emc_mode_1,
+				       emc->regs + EMC_EMRS);
+
+		if (timing->emc_mode_2 != emc->emc_mode_2)
+			writel_relaxed(timing->emc_mode_2,
+				       emc->regs + EMC_EMRS);
+
+		if (timing->emc_mode_reset != emc->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;
+			}
+			writel_relaxed(val, emc->regs + EMC_MRS);
+		}
+	} else {
+		if (timing->emc_mode_2 != emc->emc_mode_2)
+			writel_relaxed(timing->emc_mode_2,
+				       emc->regs + EMC_MRW);
+
+		if (timing->emc_mode_1 != emc->emc_mode_1)
+			writel_relaxed(timing->emc_mode_1,
+				       emc->regs + EMC_MRW);
+	}
+
+	emc->emc_mode_1 = timing->emc_mode_1;
+	emc->emc_mode_2 = timing->emc_mode_2;
+	emc->emc_mode_reset = timing->emc_mode_reset;
+
+	/* issue ZCAL command if turning ZCAL on */
+	if (emc->zcal_long) {
+		writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV0,
+			       emc->regs + EMC_ZQ_CAL);
+
+		if (dram_num > 1)
+			writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV1,
+				       emc->regs + EMC_ZQ_CAL);
+	}
+
+	/* re-enable auto-refresh */
+	writel_relaxed(EMC_REFCTRL_ENABLE_ALL(dram_num),
+		       emc->regs + EMC_REFCTRL);
+
+	/* flow control marker 3 */
+	writel_relaxed(0x1, emc->regs + EMC_UNSTALL_RW_AFTER_CLKCHANGE);
+
+	reinit_completion(&emc->clk_handshake_complete);
+
+	/* interrupt can be re-enabled now */
+	enable_irq(emc->irq);
+
+	emc->bad_state = false;
+	emc->prepared = true;
+
+	return 0;
+}
+
+static int emc_complete_timing_change(struct tegra_emc *emc,
+				      unsigned long rate)
+{
+	struct emc_timing *timing = emc_find_timing(emc, rate);
+	unsigned long timeout;
+	int ret;
+
+	timeout = wait_for_completion_timeout(&emc->clk_handshake_complete,
+					      msecs_to_jiffies(100));
+	if (timeout == 0) {
+		dev_err(emc->dev, "emc-car handshake failed\n");
+		emc->bad_state = true;
+		return -EIO;
+	}
+
+	/* restore auto-calibration */
+	if (emc->vref_cal_toggle)
+		writel_relaxed(timing->emc_auto_cal_interval,
+			       emc->regs + EMC_AUTO_CAL_INTERVAL);
+
+	/* restore dynamic self-refresh */
+	if (timing->emc_cfg_dyn_self_ref) {
+		emc->emc_cfg |= EMC_CFG_DYN_SREF_ENABLE;
+		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
+	}
+
+	/* set number of clocks to wait after each ZQ command */
+	if (emc->zcal_long)
+		writel_relaxed(timing->emc_zcal_cnt_long,
+			       emc->regs + EMC_ZCAL_WAIT_CNT);
+
+	udelay(2);
+	/* update restored timing */
+	ret = emc_seq_update_timing(emc);
+	if (ret)
+		emc->bad_state = true;
+
+	/* restore early ACK */
+	mc_writel(emc->mc, emc->mc_override, MC_EMEM_ARB_OVERRIDE);
+
+	emc->prepared = false;
+
+	return ret;
+}
+
+static int emc_unprepare_timing_change(struct tegra_emc *emc,
+				       unsigned long rate)
+{
+	if (emc->prepared && !emc->bad_state) {
+		/* shouldn't ever happen in practice */
+		dev_err(emc->dev, "timing configuration can't be reverted\n");
+		emc->bad_state = true;
+	}
+
+	return 0;
+}
+
+static int emc_clk_change_notify(struct notifier_block *nb,
+				 unsigned long msg, void *data)
+{
+	struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
+	struct clk_notifier_data *cnd = data;
+	int err;
+
+	switch (msg) {
+	case PRE_RATE_CHANGE:
+		err = emc_prepare_timing_change(emc, cnd->new_rate);
+		break;
+
+	case ABORT_RATE_CHANGE:
+		err = emc_unprepare_timing_change(emc, cnd->old_rate);
+		break;
+
+	case POST_RATE_CHANGE:
+		err = emc_complete_timing_change(emc, cnd->new_rate);
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return notifier_from_errno(err);
+}
+
+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 %pOF: failed to read rate: %d\n",
+			node, err);
+		return err;
+	}
+
+	timing->rate = value;
+
+	err = of_property_read_u32_array(node, "nvidia,emc-configuration",
+					 timing->data,
+					 ARRAY_SIZE(emc_timing_registers));
+	if (err) {
+		dev_err(emc->dev,
+			"timing %pOF: failed to read emc timing data: %d\n",
+			node, err);
+		return err;
+	}
+
+#define EMC_READ_BOOL(prop, dtprop) \
+	timing->prop = of_property_read_bool(node, dtprop);
+
+#define EMC_READ_U32(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_U32(emc_auto_cal_interval, "nvidia,emc-auto-cal-interval")
+	EMC_READ_U32(emc_mode_1, "nvidia,emc-mode-1")
+	EMC_READ_U32(emc_mode_2, "nvidia,emc-mode-2")
+	EMC_READ_U32(emc_mode_reset, "nvidia,emc-mode-reset")
+	EMC_READ_U32(emc_zcal_cnt_long, "nvidia,emc-zcal-cnt-long")
+	EMC_READ_BOOL(emc_cfg_dyn_self_ref, "nvidia,emc-cfg-dyn-self-ref")
+	EMC_READ_BOOL(emc_cfg_periodic_qrst, "nvidia,emc-cfg-periodic-qrst")
+
+#undef EMC_READ_U32
+#undef EMC_READ_BOOL
+
+	dev_dbg(emc->dev, "%s: %pOF: rate %lu\n", __func__, node, timing->rate);
+
+	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;
+
+	if (a->rate > b->rate)
+		return 1;
+
+	return 0;
+}
+
+static int emc_check_mc_timings(struct tegra_emc *emc)
+{
+	struct tegra_mc *mc = emc->mc;
+	unsigned int i;
+
+	if (emc->num_timings != mc->num_timings) {
+		dev_err(emc->dev, "emc/mc timings number mismatch: %u %u\n",
+			emc->num_timings, mc->num_timings);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < mc->num_timings; i++) {
+		if (emc->timings[i].rate != mc->timings[i].rate) {
+			dev_err(emc->dev,
+				"emc/mc timing rate mismatch: %lu %lu\n",
+				emc->timings[i].rate, mc->timings[i].rate);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int emc_load_timings_from_dt(struct tegra_emc *emc,
+				    struct device_node *node)
+{
+	struct device_node *child;
+	struct emc_timing *timing;
+	int child_count;
+	int err;
+
+	child_count = of_get_child_count(node);
+	if (!child_count) {
+		dev_err(emc->dev, "no memory timings in: %pOF\n", node);
+		return -EINVAL;
+	}
+
+	emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
+				    GFP_KERNEL);
+	if (!emc->timings)
+		return -ENOMEM;
+
+	emc->num_timings = child_count;
+	timing = emc->timings;
+
+	for_each_child_of_node(node, child) {
+		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);
+
+	err = emc_check_mc_timings(emc);
+	if (err)
+		return err;
+
+	dev_info(emc->dev,
+		 "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
+		 emc->num_timings,
+		 tegra_read_ram_code(),
+		 emc->timings[0].rate / 1000000,
+		 emc->timings[emc->num_timings - 1].rate / 1000000);
+
+	return 0;
+}
+
+static struct device_node *emc_find_node_by_ram_code(struct device *dev)
+{
+	struct device_node *np;
+	u32 value, ram_code;
+	int err;
+
+	ram_code = tegra_read_ram_code();
+
+	for_each_child_of_node(dev->of_node, np) {
+		err = of_property_read_u32(np, "nvidia,ram-code", &value);
+		if (err || value != ram_code)
+			continue;
+
+		return np;
+	}
+
+	dev_err(dev, "no memory timings for RAM code %u found in device-tree\n",
+		ram_code);
+
+	return NULL;
+}
+
+static int emc_setup_hw(struct tegra_emc *emc)
+{
+	u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
+	u32 fbio_cfg5, emc_cfg, emc_dbg;
+	enum emc_dram_type dram_type;
+
+	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
+	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
+
+	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
+
+	/* enable EMC and CAR to handshake on PLL divider/source changes */
+	emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
+
+	/* configure clock change mode accordingly to DRAM type */
+	switch (dram_type) {
+	case DRAM_TYPE_LPDDR2:
+		emc_cfg |= EMC_CLKCHANGE_PD_ENABLE;
+		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
+		break;
+
+	default:
+		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
+		emc_cfg &= ~EMC_CLKCHANGE_PD_ENABLE;
+		break;
+	}
+
+	writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);
+
+	/* initialize interrupt */
+	writel_relaxed(intmask, emc->regs + EMC_INTMASK);
+	writel_relaxed(0xffffffff, emc->regs + EMC_INTSTATUS);
+
+	/* ensure that unwanted debug features are disabled */
+	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
+	emc_dbg |= EMC_DBG_CFG_PRIORITY;
+	emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
+	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
+	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
+	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
+
+	return 0;
+}
+
+static long emc_round_rate(unsigned long rate,
+			   unsigned long min_rate,
+			   unsigned long max_rate,
+			   void *arg)
+{
+	struct emc_timing *timing = NULL;
+	struct tegra_emc *emc = arg;
+	unsigned int i;
+
+	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
+
+	for (i = 0; i < emc->num_timings; i++) {
+		if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
+			continue;
+
+		if (emc->timings[i].rate > max_rate) {
+			i = max(i, 1u) - 1;
+
+			if (emc->timings[i].rate < min_rate)
+				break;
+		}
+
+		if (emc->timings[i].rate < min_rate)
+			continue;
+
+		timing = &emc->timings[i];
+		break;
+	}
+
+	if (!timing) {
+		dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
+			rate, min_rate, max_rate);
+		return -EINVAL;
+	}
+
+	return timing->rate;
+}
+
+static int tegra_emc_probe(struct platform_device *pdev)
+{
+	struct platform_device *mc;
+	struct device_node *np;
+	struct tegra_emc *emc;
+	int err;
+
+	if (of_get_child_count(pdev->dev.of_node) == 0) {
+		dev_info(&pdev->dev,
+			 "device-tree node doesn't have memory timings\n");
+		return 0;
+	}
+
+	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
+	if (!np) {
+		dev_err(&pdev->dev, "could not get memory controller node\n");
+		return -ENOENT;
+	}
+
+	mc = of_find_device_by_node(np);
+	of_node_put(np);
+	if (!mc)
+		return -ENOENT;
+
+	np = emc_find_node_by_ram_code(&pdev->dev);
+	if (!np)
+		return -EINVAL;
+
+	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
+	if (!emc) {
+		of_node_put(np);
+		return -ENOMEM;
+	}
+
+	emc->mc = platform_get_drvdata(mc);
+	if (!emc->mc)
+		return -EPROBE_DEFER;
+
+	init_completion(&emc->clk_handshake_complete);
+	emc->clk_nb.notifier_call = emc_clk_change_notify;
+	emc->dev = &pdev->dev;
+
+	err = emc_load_timings_from_dt(emc, np);
+	of_node_put(np);
+	if (err)
+		return err;
+
+	emc->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(emc->regs))
+		return PTR_ERR(emc->regs);
+
+	err = emc_setup_hw(emc);
+	if (err)
+		return err;
+
+	err = platform_get_irq(pdev, 0);
+	if (err < 0) {
+		dev_err(&pdev->dev, "interrupt not specified: %d\n", err);
+		return err;
+	}
+	emc->irq = err;
+
+	err = devm_request_irq(&pdev->dev, emc->irq, tegra_emc_isr, 0,
+			       dev_name(&pdev->dev), emc);
+	if (err) {
+		dev_err(&pdev->dev, "failed to request irq: %d\n", err);
+		return err;
+	}
+
+	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
+
+	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);
+		goto unset_cb;
+	}
+
+	err = clk_notifier_register(emc->clk, &emc->clk_nb);
+	if (err) {
+		dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
+			err);
+		goto unset_cb;
+	}
+
+	platform_set_drvdata(pdev, emc);
+
+	return 0;
+
+unset_cb:
+	tegra20_clk_set_emc_round_callback(NULL, NULL);
+
+	return err;
+}
+
+static int tegra_emc_suspend(struct device *dev)
+{
+	struct tegra_emc *emc = dev_get_drvdata(dev);
+
+	/*
+	 * Suspending in a bad state will hang machine. The "prepared" var
+	 * shall be always false here unless it's a kernel bug that caused
+	 * suspending in a wrong order.
+	 */
+	if (WARN_ON(emc->prepared) || emc->bad_state)
+		return -EINVAL;
+
+	emc->bad_state = true;
+
+	return 0;
+}
+
+static int tegra_emc_resume(struct device *dev)
+{
+	struct tegra_emc *emc = dev_get_drvdata(dev);
+
+	emc_setup_hw(emc);
+	emc->bad_state = false;
+
+	return 0;
+}
+
+static const struct dev_pm_ops tegra_emc_pm_ops = {
+	.suspend = tegra_emc_suspend,
+	.resume = tegra_emc_resume,
+};
+
+static const struct of_device_id tegra_emc_of_match[] = {
+	{ .compatible = "nvidia,tegra30-emc", },
+	{},
+};
+
+static struct platform_driver tegra_emc_driver = {
+	.probe = tegra_emc_probe,
+	.driver = {
+		.name = "tegra30-emc",
+		.of_match_table = tegra_emc_of_match,
+		.pm = &tegra_emc_pm_ops,
+		.suppress_bind_attrs = true,
+	},
+};
+
+static int __init tegra_emc_init(void)
+{
+	return platform_driver_register(&tegra_emc_driver);
+}
+subsys_initcall(tegra_emc_init);

drivers/memory/tegra/tegra30.c

@@ -10,6 +10,46 @@
 
 #include "mc.h"
 
+#define MC_EMEM_ARB_CFG				0x90
+#define MC_EMEM_ARB_OUTSTANDING_REQ		0x94
+#define MC_EMEM_ARB_TIMING_RCD			0x98
+#define MC_EMEM_ARB_TIMING_RP			0x9c
+#define MC_EMEM_ARB_TIMING_RC			0xa0
+#define MC_EMEM_ARB_TIMING_RAS			0xa4
+#define MC_EMEM_ARB_TIMING_FAW			0xa8
+#define MC_EMEM_ARB_TIMING_RRD			0xac
+#define MC_EMEM_ARB_TIMING_RAP2PRE		0xb0
+#define MC_EMEM_ARB_TIMING_WAP2PRE		0xb4
+#define MC_EMEM_ARB_TIMING_R2R			0xb8
+#define MC_EMEM_ARB_TIMING_W2W			0xbc
+#define MC_EMEM_ARB_TIMING_R2W			0xc0
+#define MC_EMEM_ARB_TIMING_W2R			0xc4
+#define MC_EMEM_ARB_DA_TURNS			0xd0
+#define MC_EMEM_ARB_DA_COVERS			0xd4
+#define MC_EMEM_ARB_MISC0			0xd8
+#define MC_EMEM_ARB_RING1_THROTTLE		0xe0
+
+static const unsigned long tegra30_mc_emem_regs[] = {
+	MC_EMEM_ARB_CFG,
+	MC_EMEM_ARB_OUTSTANDING_REQ,
+	MC_EMEM_ARB_TIMING_RCD,
+	MC_EMEM_ARB_TIMING_RP,
+	MC_EMEM_ARB_TIMING_RC,
+	MC_EMEM_ARB_TIMING_RAS,
+	MC_EMEM_ARB_TIMING_FAW,
+	MC_EMEM_ARB_TIMING_RRD,
+	MC_EMEM_ARB_TIMING_RAP2PRE,
+	MC_EMEM_ARB_TIMING_WAP2PRE,
+	MC_EMEM_ARB_TIMING_R2R,
+	MC_EMEM_ARB_TIMING_W2W,
+	MC_EMEM_ARB_TIMING_R2W,
+	MC_EMEM_ARB_TIMING_W2R,
+	MC_EMEM_ARB_DA_TURNS,
+	MC_EMEM_ARB_DA_COVERS,
+	MC_EMEM_ARB_MISC0,
+	MC_EMEM_ARB_RING1_THROTTLE,
+};
+
 static const struct tegra_mc_client tegra30_mc_clients[] = {
 	{
 		.id = 0x00,
@@ -997,6 +1037,8 @@ const struct tegra_mc_soc tegra30_mc_soc = {
 	.atom_size = 16,
 	.client_id_mask = 0x7f,
 	.smmu = &tegra30_smmu_soc,
+	.emem_regs = tegra30_mc_emem_regs,
+	.num_emem_regs = ARRAY_SIZE(tegra30_mc_emem_regs),
 	.intmask = MC_INT_INVALID_SMMU_PAGE | MC_INT_SECURITY_VIOLATION |
 		   MC_INT_DECERR_EMEM,
 	.reset_ops = &tegra_mc_reset_ops_common,

include/soc/tegra/mc.h

@@ -181,7 +181,7 @@ struct tegra_mc {
 	spinlock_t lock;
 };
 
-void tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
+int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
 unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
 
 #endif /* __SOC_TEGRA_MC_H__ */