stm32f7: sdram: move sdram driver code to ram drivers area

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
cc: Christophe KERELLO <christophe.kerello@st.com>

3 files changed, 128 insertions, 0 deletions

diff --git a/drivers/ram/Kconfig b/drivers/ram/Kconfig
index ff09f22..61afd7a 100644
--- a/drivers/ram/Kconfig
+++ b/drivers/ram/Kconfig
@@ -16,3 +16,11 @@ config SPL_RAM
 	  If this is acceptable and you have a need to use RAM drivers in
 	  SPL, enable this option. It might provide a cleaner interface to
 	  setting up RAM (e.g. SDRAM / DDR) within SPL.
+
+config STM32_SDRAM
+	bool "Enable STM32 SDRAM support"
+	depends on RAM
+	help
+	  STM32F7 family devices support flexible memory controller(FMC) to
+	  support external memories like sdram, psram & nand.
+	  This driver is for the sdram memory interface with the FMC.
diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
index 0e10249..ecb036d 100644
--- a/drivers/ram/Makefile
+++ b/drivers/ram/Makefile
@@ -6,3 +6,4 @@
 #
 obj-$(CONFIG_RAM) += ram-uclass.o
 obj-$(CONFIG_SANDBOX) += sandbox_ram.o
+obj-$(CONFIG_STM32_SDRAM) += stm32_sdram.o
diff --git a/drivers/ram/stm32_sdram.c b/drivers/ram/stm32_sdram.c
new file mode 100644
index 0000000..13f8964
--- /dev/null
+++ b/drivers/ram/stm32_sdram.c
@@ -0,0 +1,119 @@
+/*
+ * (C) Copyright 2017
+ * Vikas Manocha, <vikas.manocha@st.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/fmc.h>
+#include <asm/arch/stm32.h>
+
+static inline u32 _ns2clk(u32 ns, u32 freq)
+{
+	u32 tmp = freq/1000000;
+	return (tmp * ns) / 1000;
+}
+
+#define NS2CLK(ns) (_ns2clk(ns, freq))
+
+/*
+ * Following are timings for IS42S16400J, from corresponding datasheet
+ */
+#define SDRAM_CAS	3	/* 3 cycles */
+#define SDRAM_NB	1	/* Number of banks */
+#define SDRAM_MWID	1	/* 16 bit memory */
+
+#define SDRAM_NR	0x1	/* 12-bit row */
+#define SDRAM_NC	0x0	/* 8-bit col */
+#define SDRAM_RBURST	0x1	/* Single read requests always as bursts */
+#define SDRAM_RPIPE	0x0	/* No HCLK clock cycle delay */
+
+#define SDRAM_TRRD	NS2CLK(12)
+#define SDRAM_TRCD	NS2CLK(18)
+#define SDRAM_TRP	NS2CLK(18)
+#define SDRAM_TRAS	NS2CLK(42)
+#define SDRAM_TRC	NS2CLK(60)
+#define SDRAM_TRFC	NS2CLK(60)
+#define SDRAM_TCDL	(1 - 1)
+#define SDRAM_TRDL	NS2CLK(12)
+#define SDRAM_TBDL	(1 - 1)
+#define SDRAM_TREF	(NS2CLK(64000000 / 8192) - 20)
+#define SDRAM_TCCD	(1 - 1)
+
+#define SDRAM_TXSR	SDRAM_TRFC	/* Row cycle time after precharge */
+#define SDRAM_TMRD	1		/* Page 10, Mode Register Set */
+
+
+/* Last data in to row precharge, need also comply ineq on page 1648 */
+#define SDRAM_TWR	max(\
+		(int)max((int)SDRAM_TRDL, (int)(SDRAM_TRAS - SDRAM_TRCD)), \
+		(int)(SDRAM_TRC - SDRAM_TRCD - SDRAM_TRP)\
+		)
+
+
+#define SDRAM_MODE_BL_SHIFT	0
+#define SDRAM_MODE_CAS_SHIFT	4
+#define SDRAM_MODE_BL		0
+#define SDRAM_MODE_CAS		SDRAM_CAS
+
+int stm32_sdram_init(void)
+{
+	u32 freq;
+
+	/*
+	 * Get frequency for NS2CLK calculation.
+	 */
+	freq = clock_get(CLOCK_AHB) / CONFIG_SYS_RAM_FREQ_DIV;
+
+	writel(CONFIG_SYS_RAM_FREQ_DIV << FMC_SDCR_SDCLK_SHIFT
+			| SDRAM_CAS << FMC_SDCR_CAS_SHIFT
+			| SDRAM_NB << FMC_SDCR_NB_SHIFT
+			| SDRAM_MWID << FMC_SDCR_MWID_SHIFT
+			| SDRAM_NR << FMC_SDCR_NR_SHIFT
+			| SDRAM_NC << FMC_SDCR_NC_SHIFT
+			| SDRAM_RPIPE << FMC_SDCR_RPIPE_SHIFT
+			| SDRAM_RBURST << FMC_SDCR_RBURST_SHIFT,
+			&STM32_SDRAM_FMC->sdcr1);
+
+	writel(SDRAM_TRCD << FMC_SDTR_TRCD_SHIFT
+			| SDRAM_TRP << FMC_SDTR_TRP_SHIFT
+			| SDRAM_TWR << FMC_SDTR_TWR_SHIFT
+			| SDRAM_TRC << FMC_SDTR_TRC_SHIFT
+			| SDRAM_TRAS << FMC_SDTR_TRAS_SHIFT
+			| SDRAM_TXSR << FMC_SDTR_TXSR_SHIFT
+			| SDRAM_TMRD << FMC_SDTR_TMRD_SHIFT,
+			&STM32_SDRAM_FMC->sdtr1);
+
+	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK,
+	       &STM32_SDRAM_FMC->sdcmr);
+	udelay(200);	/* 200 us delay, page 10, "Power-Up" */
+	FMC_BUSY_WAIT();
+
+	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE,
+	       &STM32_SDRAM_FMC->sdcmr);
+	udelay(100);
+	FMC_BUSY_WAIT();
+
+	writel((FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_AUTOREFRESH
+		| 7 << FMC_SDCMR_NRFS_SHIFT), &STM32_SDRAM_FMC->sdcmr);
+	udelay(100);
+	FMC_BUSY_WAIT();
+
+	writel(FMC_SDCMR_BANK_1 | (SDRAM_MODE_BL << SDRAM_MODE_BL_SHIFT
+	       | SDRAM_MODE_CAS << SDRAM_MODE_CAS_SHIFT)
+	       << FMC_SDCMR_MODE_REGISTER_SHIFT | FMC_SDCMR_MODE_WRITE_MODE,
+	       &STM32_SDRAM_FMC->sdcmr);
+	udelay(100);
+	FMC_BUSY_WAIT();
+
+	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL,
+	       &STM32_SDRAM_FMC->sdcmr);
+	FMC_BUSY_WAIT();
+
+	/* Refresh timer */
+	writel(SDRAM_TREF, &STM32_SDRAM_FMC->sdrtr);
+
+	return 0;
+}