commit bfea69ad27936d619c0eb3c1be55cc292df8d7f5
author Vikas Manocha <vikas.manocha@st.com> Mon Apr 10 15:03:03 2017 -0700
committer Tom Rini <trini@konsulko.com> Mon May 08 11:57:22 2017 -0400
tree 14e38035d8f8d84ec50fc92a62536ced09a40e92
parent a241c241cf2b08bb7905f4825e76e49944648b60

stm32f7: sdram: correct sdram configuration as per micron sdram

Actually the sdram memory on stm32f746 discovery board is micron part
MT48LC_4M32_B2B5_6A. This patch does the modification required in the
device tree node & driver for the same.

Also we are passing here all the timing parameters in terms of clock
cycles, so no need to convert time(ns or ms) to cycles.

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

drivers/ram/stm32_sdram.c

diff --git a/drivers/ram/stm32_sdram.c b/drivers/ram/stm32_sdram.c
index 5e09f35..48b4979 100644
--- a/drivers/ram/stm32_sdram.c
+++ b/drivers/ram/stm32_sdram.c
@@ -21,6 +21,7 @@
 	u8 memory_width;
 	u8 no_banks;
 	u8 cas_latency;
+	u8 sdclk;
 	u8 rd_burst;
 	u8 rd_pipe_delay;
 };
@@ -31,51 +32,25 @@
 	u8 tras;
 	u8 trc;
 	u8 trp;
+	u8 twr;
 	u8 trcd;
 };
 struct stm32_sdram_params {
 	u8 no_sdram_banks;
 	struct stm32_sdram_control sdram_control;
 	struct stm32_sdram_timing sdram_timing;
+	u32 sdram_ref_count;
 };
-static inline u32 _ns2clk(u32 ns, u32 freq)
-{
-	u32 tmp = freq/1000000;
-	return (tmp * ns) / 1000;
-}
-
-#define NS2CLK(ns) (_ns2clk(ns, freq))
-
-#define SDRAM_TREF	(NS2CLK(64000000 / 8192) - 20)
 
 #define SDRAM_MODE_BL_SHIFT	0
 #define SDRAM_MODE_CAS_SHIFT	4
 #define SDRAM_MODE_BL		0
-#define SDRAM_MODE_CAS		3
-
-#define SDRAM_TRDL	12
 
 int stm32_sdram_init(struct udevice *dev)
 {
-	u32 freq;
-	u32 sdram_twr;
 	struct stm32_sdram_params *params = dev_get_platdata(dev);
 
-	/*
-	 * Get frequency for NS2CLK calculation.
-	 */
-	freq = clock_get(CLOCK_AHB) / CONFIG_SYS_RAM_FREQ_DIV;
-	debug("%s, sdram freq = %d\n", __func__, freq);
-
-	/* Last data in to row precharge, need also comply ineq on page 1648 */
-	sdram_twr = max(
-			max(SDRAM_TRDL, params->sdram_timing.tras
-			    - params->sdram_timing.trcd),
-			params->sdram_timing.trc - params->sdram_timing.trcd
-			- params->sdram_timing.trp
-		       );
-
-	writel(CONFIG_SYS_RAM_FREQ_DIV << FMC_SDCR_SDCLK_SHIFT
+	writel(params->sdram_control.sdclk << FMC_SDCR_SDCLK_SHIFT
 		| params->sdram_control.cas_latency << FMC_SDCR_CAS_SHIFT
 		| params->sdram_control.no_banks << FMC_SDCR_NB_SHIFT
 		| params->sdram_control.memory_width << FMC_SDCR_MWID_SHIFT
@@ -85,13 +60,13 @@
 		| params->sdram_control.rd_burst << FMC_SDCR_RBURST_SHIFT,
 		&STM32_SDRAM_FMC->sdcr1);
 
-	writel(NS2CLK(params->sdram_timing.trcd) << FMC_SDTR_TRCD_SHIFT
-		| NS2CLK(params->sdram_timing.trp) << FMC_SDTR_TRP_SHIFT
-		| NS2CLK(sdram_twr) << FMC_SDTR_TWR_SHIFT
-		| NS2CLK(params->sdram_timing.trc) << FMC_SDTR_TRC_SHIFT
-		| NS2CLK(params->sdram_timing.tras) << FMC_SDTR_TRAS_SHIFT
-		| NS2CLK(params->sdram_timing.txsr) << FMC_SDTR_TXSR_SHIFT
-		| NS2CLK(params->sdram_timing.tmrd) << FMC_SDTR_TMRD_SHIFT,
+	writel(params->sdram_timing.trcd << FMC_SDTR_TRCD_SHIFT
+		| params->sdram_timing.trp << FMC_SDTR_TRP_SHIFT
+		| params->sdram_timing.twr << FMC_SDTR_TWR_SHIFT
+		| params->sdram_timing.trc << FMC_SDTR_TRC_SHIFT
+		| params->sdram_timing.tras << FMC_SDTR_TRAS_SHIFT
+		| params->sdram_timing.txsr << FMC_SDTR_TXSR_SHIFT
+		| params->sdram_timing.tmrd << FMC_SDTR_TMRD_SHIFT,
 		&STM32_SDRAM_FMC->sdtr1);
 
 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK,
@@ -110,7 +85,7 @@
 	FMC_BUSY_WAIT();
 
 	writel(FMC_SDCMR_BANK_1 | (SDRAM_MODE_BL << SDRAM_MODE_BL_SHIFT
-	       | SDRAM_MODE_CAS << SDRAM_MODE_CAS_SHIFT)
+	       | params->sdram_control.cas_latency << SDRAM_MODE_CAS_SHIFT)
 	       << FMC_SDCMR_MODE_REGISTER_SHIFT | FMC_SDCMR_MODE_WRITE_MODE,
 	       &STM32_SDRAM_FMC->sdcmr);
 	udelay(100);
@@ -121,7 +96,7 @@
 	FMC_BUSY_WAIT();
 
 	/* Refresh timer */
-	writel(SDRAM_TREF, &STM32_SDRAM_FMC->sdrtr);
+	writel((params->sdram_ref_count) << 1, &STM32_SDRAM_FMC->sdrtr);
 
 	return 0;
 }
@@ -142,12 +117,14 @@
 					    sizeof(params->sdram_control));
 		if (ret)
 			return ret;
-
 		ret = fdtdec_get_byte_array(blob, node, "st,sdram-timing",
 					    (u8 *)&params->sdram_timing,
 					    sizeof(params->sdram_timing));
 		if (ret)
 			return ret;
+
+		params->sdram_ref_count = fdtdec_get_int(blob, node,
+						"st,sdram-refcount", 8196);
 	}
 
 	return 0;