[PATCH v2 08/16] ARM: at91: import low level DDRAMC initialization code from at91bootstrap

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

This commit imports DDRAMC initialization routines for use in PBL from
https://github.com/linux4sam/at91bootstrap/blob/v3.8.12/driver/ddramc.c

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/mach-at91/Makefile              |   1 +
 arch/arm/mach-at91/ddramc.c              | 518 +++++++++++++++++++++++
 arch/arm/mach-at91/include/mach/ddramc.h |  35 ++
 3 files changed, 554 insertions(+)
 create mode 100644 arch/arm/mach-at91/ddramc.c
 create mode 100644 arch/arm/mach-at91/include/mach/ddramc.h

diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index b8ff6428d05a..ac88f83f9fe5 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -1,6 +1,7 @@
 obj-y += setup.o
 pbl-y += lowlevel_clock.o
 pbl-$(CONFIG_CLOCKSOURCE_ATMEL_PIT) += early_udelay.o
+pbl-y += ddramc.o
 
 ifeq ($(CONFIG_COMMON_CLK_OF_PROVIDER),)
 obj-y += clock.o
diff --git a/arch/arm/mach-at91/ddramc.c b/arch/arm/mach-at91/ddramc.c
new file mode 100644
index 000000000000..585917b9070c
--- /dev/null
+++ b/arch/arm/mach-at91/ddramc.c
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: BSD-1-Clause
+/*
+ * Copyright (c) 2007, Stelian Pop <stelian.pop@leadtechdesign.com>
+ * Copyright (c) 2007 Lead Tech Design <www.leadtechdesign.com>
+ */
+
+#include <linux/kconfig.h>
+#include <asm/system.h>
+#include <mach/at91_ddrsdrc.h>
+#include <mach/ddramc.h>
+#include <mach/early_udelay.h>
+
+static bool ddramc_decodtype_is_seq(unsigned long ddramc_cr)
+{
+	if (IS_ENABLED(CONFIG_SOC_AT91SAM9X5) || IS_ENABLED(CONFIG_SOC_AT91SAM9N12)
+	    || IS_ENABLED(CONFIG_SOC_SAMA5)) {
+		if (ddramc_cr & AT91C_DDRC2_DECOD_INTERLEAVED)
+			return false;
+	}
+	return true;
+}
+
+
+void at91_ddram_initialize(unsigned long base_address,
+			   unsigned long ram_address,
+			   struct at91_ddramc_register *ddramc_config)
+{
+	unsigned long ba_offset;
+	unsigned long cr = 0;
+
+	/* compute BA[] offset according to CR configuration */
+	ba_offset = (ddramc_config->cr & AT91C_DDRC2_NC) + 9;
+	if (ddramc_decodtype_is_seq(ddramc_config->cr))
+		ba_offset += ((ddramc_config->cr & AT91C_DDRC2_NR) >> 2) + 11;
+
+	ba_offset += (ddramc_config->mdr & AT91C_DDRC2_DBW) ? 1 : 2;
+
+	/*
+	 * Step 1: Program the memory device type into the Memory Device Register
+	 */
+	writel(ddramc_config->mdr, base_address + AT91C_HDDRSDRC2_MDR);
+
+	/*
+	 * Step 2: Program the feature of DDR2-SDRAM device into
+	 * the Timing Register, and into the Configuration Register
+	 */
+	writel(ddramc_config->cr, base_address + AT91C_HDDRSDRC2_CR);
+
+	writel(ddramc_config->t0pr, base_address + AT91C_HDDRSDRC2_T0PR);
+	writel(ddramc_config->t1pr, base_address + AT91C_HDDRSDRC2_T1PR);
+	writel(ddramc_config->t2pr, base_address + AT91C_HDDRSDRC2_T2PR);
+
+	/*
+	 * Step 3: An NOP command is issued to the DDR2-SDRAM
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+	/* Now, clocks which drive the DDR2-SDRAM device are enabled */
+
+	/* A minimum pause wait 200 us is provided to precede any signal toggle.
+	   (6 core cycles per iteration, core is at 396MHz: min 13340 loops) */
+	early_udelay(200);
+
+	/*
+	 * Step 4:  An NOP command is issued to the DDR2-SDRAM
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+	/* Now, CKE is driven high */
+	/* wait 400 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 5: An all banks precharge command is issued to the DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MODE_PRCGALL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 6: An Extended Mode Register set(EMRS2) cycle is issued to chose between commercial or high
+	 * temperature operations.
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1] is set to 1 and BA[0] is set to 0.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x2 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 7: An Extended Mode Register set(EMRS3) cycle is issued
+	 * to set the Extended Mode Register to "0".
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1] is set to 1 and BA[0] is set to 1.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x3 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 8: An Extened Mode Register set(EMRS1) cycle is issued to enable DLL,
+	 * and to program D.I.C(Output Driver Impedance Control)
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1] is set to 0 and BA[0] is set to 1.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x1 << ba_offset));
+
+	/* An additional 200 cycles of clock are required for locking DLL */
+	early_udelay(1);
+
+	/*
+	 * Step 9: Program DLL field into the Configuration Register to high(Enable DLL reset)
+	 */
+	cr = readl(base_address + AT91C_HDDRSDRC2_CR);
+	writel(cr | AT91C_DDRC2_ENABLE_RESET_DLL, base_address + AT91C_HDDRSDRC2_CR);
+
+	/*
+	 * Step 10: A Mode Register set(MRS) cycle is issied to reset DLL.
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1:0] bits are set to 0.
+	 */
+	writel(AT91C_DDRC2_MODE_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x0 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 11: An all banks precharge command is issued to the DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MODE_PRCGALL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/* wait 400 ns min (not needed on certain DDR2 devices) */
+	early_udelay(1);
+
+	/*
+	 * Step 12: Two auto-refresh (CBR) cycles are provided.
+	 * Program the auto refresh command (CBR) into the Mode Register.
+	 */
+	writel(AT91C_DDRC2_MODE_RFSH_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/* wait TRFC cycles min (135 ns min) extended to 400 ns */
+	early_udelay(1);
+
+	/* Set 2nd CBR */
+	writel(AT91C_DDRC2_MODE_RFSH_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/* wait TRFC cycles min (135 ns min) extended to 400 ns */
+	early_udelay(1);
+
+	/*
+	 * Step 13: Program DLL field into the Configuration Register to low(Disable DLL reset).
+	 */
+	cr = readl(base_address + AT91C_HDDRSDRC2_CR);
+	writel(cr & ~AT91C_DDRC2_ENABLE_RESET_DLL, base_address + AT91C_HDDRSDRC2_CR);
+
+	/*
+	 * Step 14: A Mode Register set (MRS) cycle is issued to program
+	 * the parameters of the DDR2-SDRAM devices, in particular CAS latency,
+	 * burst length and to disable DDL reset.
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1:0] bits are set to 0.
+	 */
+	writel(AT91C_DDRC2_MODE_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x0 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 15: Program OCD field into the Configuration Register
+	 * to high (OCD calibration default).
+	 */
+	cr = readl(base_address + AT91C_HDDRSDRC2_CR);
+	writel(cr | AT91C_DDRC2_OCD_DEFAULT, base_address + AT91C_HDDRSDRC2_CR);
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 16: An Extended Mode Register set (EMRS1) cycle is issued to OCD default value.
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1] is set to 0 and BA[0] is set to 1.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x1 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 17: Program OCD field into the Configuration Register
+	 * to low (OCD calibration mode exit).
+	 */
+	cr = readl(base_address + AT91C_HDDRSDRC2_CR);
+	writel(cr & ~AT91C_DDRC2_OCD_DEFAULT, base_address + AT91C_HDDRSDRC2_CR);
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 18: An Extended Mode Register set (EMRS1) cycle is issued to enable OCD exit.
+	 * Perform a write access to DDR2-SDRAM to acknowledge this command.
+	 * The write address must be chosen so that BA[1] is set to 0 and BA[0] is set to 1.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x1 << ba_offset));
+
+	/* wait 2 cycles min (of tCK) = 15 ns min */
+	early_udelay(1);
+
+	/*
+	 * Step 19: A Nornal mode command is provided.
+	 */
+	writel(AT91C_DDRC2_MODE_NORMAL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 20: Perform a write access to any DDR2-SDRAM address
+	 */
+	writel(0, ram_address);
+
+	/*
+	 * Step 21: Write the refresh rate into the count field in the Refresh Timer register.
+	 */
+	writel(ddramc_config->rtr, base_address + AT91C_HDDRSDRC2_RTR);
+
+	/*
+	 * Now we are ready to work on the DDRSDR
+	 *  wait for end of calibration
+	 */
+	early_udelay(10);
+}
+
+/* This initialization sequence is sama5d3 and sama5d4 LP-DDR2 specific */
+
+void at91_lpddr2_sdram_initialize(unsigned long base_address,
+				  unsigned long ram_address,
+				  struct at91_ddramc_register *ddramc_config)
+{
+	unsigned long reg;
+
+	writel(ddramc_config->lpddr2_lpr, base_address + AT91C_MPDDRC_LPDDR2_LPR);
+
+	writel(ddramc_config->tim_calr, base_address + AT91C_MPDDRC_LPDDR2_TIM_CAL);
+
+	/*
+	 * Step 1: Program the memory device type.
+	 */
+	writel(ddramc_config->mdr, base_address + AT91C_HDDRSDRC2_MDR);
+
+	/*
+	 * Step 2: Program the feature of the low-power DDR2-SDRAM device.
+	 */
+	writel(ddramc_config->cr, base_address + AT91C_HDDRSDRC2_CR);
+
+	writel(ddramc_config->t0pr, base_address + AT91C_HDDRSDRC2_T0PR);
+	writel(ddramc_config->t1pr, base_address + AT91C_HDDRSDRC2_T1PR);
+	writel(ddramc_config->t2pr, base_address + AT91C_HDDRSDRC2_T2PR);
+
+	/*
+	 * Step 3: A NOP command is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+
+	/*
+	 * Step 3bis: Add memory barrier then Perform a write access to
+	 * any low-power DDR2-SDRAM address to acknowledge the command.
+	 */
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 4: A pause of at least 100 ns must be observed before
+	 * a single toggle.
+	 */
+	early_udelay(1);
+
+	/*
+	 * Step 5: A NOP command is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 6: A pause of at least 200 us must be observed before a Reset
+	 * Command.
+	 */
+	early_udelay(200);
+
+	/*
+	 * Step 7: A Reset command is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MRS(63) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 8: A pause of at least tINIT5 must be observed before issuing
+	 * any commands.
+	 */
+	early_udelay(1);
+
+	/*
+	 * Step 9: A Calibration command is issued to the low-power DDR2-SDRAM.
+	 */
+	reg = readl(base_address + AT91C_HDDRSDRC2_CR);
+	reg &= ~AT91C_DDRC2_ZQ;
+	reg |= AT91C_DDRC2_ZQ_RESET;
+	writel(reg, base_address + AT91C_HDDRSDRC2_CR);
+
+	writel(AT91C_DDRC2_MRS(10) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 9bis: The ZQ Calibration command is now issued.
+	 * Program the type of calibration in the MPDDRC_CR: set the
+	 * ZQ field to the SHORT value.
+	 */
+	reg = readl(base_address + AT91C_HDDRSDRC2_CR);
+	reg &= ~AT91C_DDRC2_ZQ;
+	reg |= AT91C_DDRC2_ZQ_SHORT;
+	writel(reg, base_address + AT91C_HDDRSDRC2_CR);
+
+	/*
+	 * Step 10: A Mode Register Write command with 1 to the MRS field
+	 * is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MRS(1) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 11: A Mode Register Write command with 2 to the MRS field
+	 * is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MRS(2) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 12: A Mode Register Write command with 3 to the MRS field
+	 * is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MRS(3) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 13: A Mode Register Write command with 16 to the MRS field
+	 * is issued to the low-power DDR2-SDRAM.
+	 */
+	writel(AT91C_DDRC2_MRS(16) | AT91C_DDRC2_MODE_LPDDR2_CMD,
+		     base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 14: A Normal Mode command is provided.
+	 */
+	writel(AT91C_DDRC2_MODE_NORMAL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	dmb();
+	writel(0, ram_address);
+
+	/*
+	 * Step 15: close the input buffers: error in documentation: no need.
+	 */
+
+	/*
+	 * Step 16: Write the refresh rate into the COUNT field in the MPDDRC
+	 * Refresh Timer Register.
+	 */
+	writel(ddramc_config->rtr, base_address + AT91C_HDDRSDRC2_RTR);
+
+	/*
+	 * Now configure the CAL MR4 register.
+	 */
+	writel(ddramc_config->cal_mr4r, base_address + AT91C_MPDDRC_LPDDR2_CAL_MR4);
+}
+
+void at91_lpddr1_sdram_initialize(unsigned long base_address,
+				  unsigned long ram_address,
+				  struct at91_ddramc_register *ddramc_config)
+{
+	unsigned long ba_offset;
+
+	/* Compute BA[] offset according to CR configuration */
+	ba_offset = (ddramc_config->cr & AT91C_DDRC2_NC) + 8;
+	if (!(ddramc_config->cr & AT91C_DDRC2_DECOD_INTERLEAVED))
+		ba_offset += ((ddramc_config->cr & AT91C_DDRC2_NR) >> 2) + 11;
+
+	ba_offset += (ddramc_config->mdr & AT91C_DDRC2_DBW) ? 1 : 2;
+
+	/*
+	 * Step 1: Program the memory device type in the MPDDRC Memory Device Register
+	 */
+	writel(ddramc_config->mdr, base_address + AT91C_HDDRSDRC2_MDR);
+
+	/*
+	 * Step 2: Program the features of the low-power DDR1-SDRAM device
+	 * in the MPDDRC Configuration Register and in the MPDDRC Timing
+	 * Parameter 0 Register/MPDDRC Timing Parameter 1 Register.
+	 */
+	writel(ddramc_config->cr, base_address + AT91C_HDDRSDRC2_CR);
+
+	writel(ddramc_config->t0pr, base_address + AT91C_HDDRSDRC2_T0PR);
+	writel(ddramc_config->t1pr, base_address + AT91C_HDDRSDRC2_T1PR);
+	writel(ddramc_config->t2pr, base_address + AT91C_HDDRSDRC2_T2PR);
+
+	/*
+	 * Step 3: Program Temperature Compensated Self-refresh (TCR),
+	 * Partial Array Self-refresh (PASR) and Drive Strength (DS) parameters
+	 * in the MPDDRC Low-power Register.
+	 */
+	writel(ddramc_config->lpr, base_address + AT91C_HDDRSDRC2_LPR);
+
+	/*
+	 * Step 4: A NOP command is issued to the low-power DDR1-SDRAM.
+	 * Program the NOP command in the MPDDRC Mode Register (MPDDRC_MR).
+	 * The clocks which drive the low-power DDR1-SDRAM device
+	 * are now enabled.
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 5: A pause of at least 200 us must be observed before
+	 * a signal toggle.
+	 */
+	early_udelay(200);
+
+	/*
+	 * Step 6: A NOP command is issued to the low-power DDR1-SDRAM.
+	 * Program the NOP command in the MPDDRC_MR. calibration request is
+	 * now made to the I/O pad.
+	 */
+	writel(AT91C_DDRC2_MODE_NOP_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 7: An All Banks Precharge command is issued
+	 * to the low-power DDR1-SDRAM.
+	 * Program All Banks Precharge command in the MPDDRC_MR.
+	 */
+	writel(AT91C_DDRC2_MODE_PRCGALL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 8: Two auto-refresh (CBR) cycles are provided.
+	 * Program the Auto Refresh command (CBR) in the MPDDRC_MR.
+	 * The application must write a four to the MODE field
+	 * in the MPDDRC_MR. Perform a write access to any low-power
+	 * DDR1-SDRAM location twice to acknowledge these commands.
+	 */
+	writel(AT91C_DDRC2_MODE_RFSH_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	writel(AT91C_DDRC2_MODE_RFSH_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 9: An Extended Mode Register Set (EMRS) cycle is issued to
+	 * program the low-power DDR1-SDRAM parameters (TCSR, PASR, DS).
+	 * The application must write a five to the MODE field in the MPDDRC_MR
+	 * and perform a write access to the SDRAM to acknowledge this command.
+	 * The write address must be chosen so that signal BA[1] is set to 1
+	 * and BA[0] is set to 0.
+	 */
+	writel(AT91C_DDRC2_MODE_EXT_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x2 << ba_offset));
+
+	/*
+	 * Step 10: A Mode Register Set (MRS) cycle is issued to program
+	 * parameters of the low-power DDR1-SDRAM devices, in particular
+	 * CAS latency.
+	 * The application must write a three to the MODE field in the MPDDRC_MR
+	 * and perform a write access to the SDRAM to acknowledge this command.
+	 * The write address must be chosen so that signals BA[1:0] are set to 0.
+	 */
+	writel(AT91C_DDRC2_MODE_LMR_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address + (0x0 << ba_offset));
+
+	/*
+	 * Step 11: The application must enter Normal mode, write a zero
+	 * to the MODE field in the MPDDRC_MR and perform a write access
+	 * at any location in the SDRAM to acknowledge this command.
+	 */
+	writel(AT91C_DDRC2_MODE_NORMAL_CMD, base_address + AT91C_HDDRSDRC2_MR);
+	writel(0, ram_address);
+
+	/*
+	 * Step 12: Perform a write access to any low-power DDR1-SDRAM address.
+	 */
+	writel(0, ram_address);
+
+	/*
+	 * Step 14: Write the refresh rate into the COUNT field in the MPDDRC
+	 * Refresh Timer Register (MPDDRC_RTR):
+	 */
+	writel(ddramc_config->rtr, base_address + AT91C_HDDRSDRC2_RTR);
+}
diff --git a/arch/arm/mach-at91/include/mach/ddramc.h b/arch/arm/mach-at91/include/mach/ddramc.h
new file mode 100644
index 000000000000..984b68c076da
--- /dev/null
+++ b/arch/arm/mach-at91/include/mach/ddramc.h
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: BSD-1-Clause
+/*
+ * Copyright (c) 2006, Atmel Corporation
+ */
+#ifndef __DDRAMC_H__
+#define __DDRAMC_H__
+
+struct at91_ddramc_register {
+	unsigned long mdr;
+	unsigned long cr;
+	unsigned long rtr;
+	unsigned long t0pr;
+	unsigned long t1pr;
+	unsigned long t2pr;
+	unsigned long lpr;
+	unsigned long lpddr2_lpr;
+	unsigned long tim_calr;
+	unsigned long cal_mr4r;
+};
+
+void at91_ddram_initialize(unsigned long base_address,
+			   unsigned long ram_address,
+			   struct at91_ddramc_register *ddramc_config);
+
+void at91_lpddr2_sdram_initialize(unsigned long base_address,
+				  unsigned long ram_address,
+				  struct at91_ddramc_register *ddramc_config);
+
+
+void at91_lpddr1_sdram_initialize(unsigned long base_address,
+				  unsigned long ram_address,
+				  struct at91_ddramc_register *ddramc_config);
+
+
+#endif /* #ifndef __DDRAMC_H__ */
-- 
2.20.1


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