RT #90499: STM32F4X9-SOM NOR/SDRAM errata 2.8.7 fix

Copy image from NOR to SDRAM through On-Chip RAM buffer
setting SDRAM to Self-Refresh on each copy.

Implement flash_read16, flash_write16 and flash_write_buffer
to disable/enable SDRAM on flash access.

Start and immediately put SDRAM in self-refresh on start-up for flash
to work correctly.

board/emcraft/stm-som/board.c

@@ -35,6 +35,9 @@
 
 #if CONFIG_SYS_BOARD_REV == 0x2A
 # include <asm/arch/fmc.h>
+# include <flash.h>
+# include <asm/io.h>
+# include <asm/system.h>
 #endif
 
 #include <asm/arch/fsmc.h>
@@ -217,16 +220,56 @@ out:
 int board_init(void)
 {
 	int rv;
+#if CONFIG_SYS_BOARD_REV == 0x2A
+	int i;
+	char v;
+#endif
 
 	rv = fmc_fsmc_setup_gpio();
 	if (rv)
 		return rv;
 
 #if !defined(CONFIG_SYS_NO_FLASH)
+
+#if CONFIG_SYS_BOARD_REV == 0x2A
+	/* Disable first bank */
+	fsmc_nor_psram_init(1, 0, 0, 0);
+	fsmc_nor_psram_init(3, 0, 0, 0);
+	fsmc_nor_psram_init(4, 0, 0, 0);
+
+	/*
+	 * Put SDRAM in Self-refresh mode to workaround
+	 * bug with Flash/SDRAM accessing,
+	 * see errata 2.8.7
+	 */
+	STM32_RCC->ahb3enr |= 1;
+	__asm__ __volatile__ ("dsb" : : : "memory");
+
+	STM32_SDRAM_FMC->sdcr1 =
+		CONFIG_SYS_RAM_FREQ_DIV << FMC_SDCR_SDCLK_SHIFT;
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK;
+	FMC_BUSY_WAIT();
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_SELFREFRESH;
+	FMC_BUSY_WAIT();
+	udelay(60);
+#endif
+
 	if ((rv = fsmc_nor_psram_init(CONFIG_SYS_FLASH_CS, CONFIG_SYS_FSMC_FLASH_BCR,
 			CONFIG_SYS_FSMC_FLASH_BTR,
 			CONFIG_SYS_FSMC_FLASH_BWTR)))
 		return rv;
+
+#if CONFIG_SYS_BOARD_REV == 0x2A
+	for (i = 1; i < 0x1000000; i <<= 1) {
+		v = *(volatile char*)(0x64000000 + i);
+		v = *(volatile char*)(0x64000000 + i - 1);
+		nop(); nop();
+		nop(); nop();
+		nop(); nop();
+	}
+#endif
 #endif
 
 	return 0;
@@ -336,6 +379,8 @@ out:
  */
 #define STM32_RCC_ENR_FMC		(1 << 0)	/* FMC module clock  */
 
+static int dram_initialized = 0;
+
 
 static inline u32 _ns2clk(u32 ns, u32 freq)
 {
@@ -398,7 +443,7 @@ int dram_init(void)
 		SDRAM_MWID << FMC_SDCR_MWID_SHIFT |
 		SDRAM_NR << FMC_SDCR_NR_SHIFT |
 		SDRAM_NC << FMC_SDCR_NC_SHIFT |
-		1 << FMC_SDCR_RPIPE_SHIFT |
+		0 << FMC_SDCR_RPIPE_SHIFT |
 		1 << FMC_SDCR_RBURST_SHIFT
 	);
 
@@ -415,10 +460,12 @@ int dram_init(void)
 	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK;
 
 	udelay(200);	/* 200 us delay, page 10, "Power-Up" */
+	FMC_BUSY_WAIT();
 
 	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE;
 
 	udelay(100);
+	FMC_BUSY_WAIT();
 
 	STM32_SDRAM_FMC->sdcmr = (
 		FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_AUTOREFRESH |
@@ -426,6 +473,8 @@ int dram_init(void)
 	);
 
 	udelay(100);
+	FMC_BUSY_WAIT();
+
 
 #define SDRAM_MODE_BL_SHIFT		0
 #define SDRAM_MODE_CAS_SHIFT		4
@@ -441,7 +490,11 @@ int dram_init(void)
 
 	udelay(100);
 
-	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1;
+	FMC_BUSY_WAIT();
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL;
+
+	FMC_BUSY_WAIT();
 
 	/* Refresh timer */
 	STM32_SDRAM_FMC->sdrtr = SDRAM_TREF;
@@ -456,8 +509,127 @@ int dram_init(void)
 
 	cortex_m3_mpu_full_access();
 
+	dram_initialized = 1;
+
 	return rv;
 }
+
+/*
+ * STM32 Flash bug workaround.
+ */
+extern char	_mem_ram_buf_base, _mem_ram_buf_size;
+
+#define SOC_RAM_BUFFER_BASE	(ulong)(&_mem_ram_buf_base)
+#define SOC_RAM_BUFFER_SIZE	(ulong)((&_mem_ram_buf_size) - 0x100)
+
+void stop_ram(void)
+{
+	if (!dram_initialized)
+		return;
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_SELFREFRESH;
+
+	FMC_BUSY_WAIT();
+}
+
+void start_ram(void)
+{
+	if (!dram_initialized)
+		return;
+
+	/*
+	 * Precharge according to chip requirement, page 12.
+	 */
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE;
+	FMC_BUSY_WAIT();
+
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL;
+	FMC_BUSY_WAIT();
+
+	udelay(60);
+}
+
+#define NOP10()		do {	nop(); nop(); nop(); nop(); nop(); \
+				nop(); nop(); nop(); nop(); nop(); \
+			} while(0);
+
+u16 flash_read16(void *addr)
+{
+	u16 value;
+	stop_ram();
+	value = __raw_readw(addr);
+	NOP10();
+	start_ram();
+	return value;
+}
+
+void flash_write16(u16 value, void *addr)
+{
+	stop_ram();
+	__raw_writew(value, addr);
+	NOP10();
+	NOP10();
+	start_ram();
+}
+
+__attribute__((noinline)) void copy_one(volatile u16* src, volatile u16* dst)
+{
+	*dst = *src;
+}
+
+u32 flash_write_buffer(void *src, void *dst, int cnt, int portwidth)
+{
+	u32 retval = 0;
+
+	if (portwidth != FLASH_CFI_16BIT) {
+		retval = ERR_INVAL;
+		goto out;
+	}
+
+	memcpy((void*)SOC_RAM_BUFFER_BASE, (void*)src, cnt * portwidth);
+
+	stop_ram();
+	__asm__ __volatile__("": : :"memory");
+
+	src = (void*) SOC_RAM_BUFFER_BASE;
+
+	while(cnt-- > 0) {
+		copy_one(src, dst);
+		src += 2, dst += 2;
+		NOP10();
+		NOP10();
+	}
+
+	__asm__ __volatile__("": : :"memory");
+	start_ram();
+out:
+	return retval;
+}
+
+u32 flash_check_flag(void *src, void *dst, int cnt, int portwidth)
+{
+	u32 flag = 1;
+
+	if (portwidth != FLASH_CFI_16BIT) {
+		flag = 0;
+		goto out;
+	}
+
+	stop_ram();
+
+	while((cnt-- > 0) && (flag == 1)) {
+		flag = *(u16*)dst == 0xFFFF;
+		dst += 2;
+	}
+
+	start_ram();
+
+out:
+	return flag;
+}
+
 #endif /* CONFIG_SYS_BOARD_REV == 0x2A */
 
 

cpu/arm_cortexm3/stm32/Makefile

@@ -30,6 +30,9 @@ include $(TOPDIR)/config.mk
 LIB	= $(obj)lib$(SOC).a
 
 COBJS	:= clock.o cpu.o envm.o wdt.o fsmc.o
+ifeq ($(CONFIG_CMD_BUFCOPY),y)
+COBJS	+= cmd_bufcopy.o
+endif
 SOBJS	:=
 
 SRCS	:= $(COBJS:.o=.c)

cpu/arm_cortexm3/stm32/cmd_bufcopy.c

+/*
+ * (C) Copyright 2013
+ * Pavel Boldin, Emcraft Systems, paboldin@emcraft.com
+ *
+ * This is command to do a safe copy from NOR flash into SDRAM through
+ * SRAM buffer to workaround errata 2.8.7
+ * (SDRAM and NOR flash can't be accessed simultaneously).
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <command.h>
+#include <string.h>
+#include <asm/arch/fmc.h>
+#include <asm/errno.h>
+
+/*
+ * Base address and the length of buffer in internal RAM, which
+ * we use as a source for buffer to be written to eNVM.
+ * Size of this buffer is set in the configuration file, address
+ * (position within internal RAM) is calculated automatically, at
+ * linking stage. Thus, the appropriate symbols are exported from
+ * the linker script *.lds.
+ */
+extern char	_mem_ram_buf_base, _mem_ram_buf_size;
+
+#define SOC_RAM_BUFFER_BASE	(ulong)(&_mem_ram_buf_base)
+#define SOC_RAM_BUFFER_SIZE	(ulong)((&_mem_ram_buf_size) - 0x100)
+
+
+int nor_sdram_bufcopy_onebuf(ulong dst, ulong src, ulong size)
+{
+	int ret = 0;
+
+	if (size > SOC_RAM_BUFFER_SIZE) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/*
+	 * Switch memory to self-refresh mode.
+	 * Controller issues PALL command automatically before that.
+	 */
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_SELFREFRESH;
+
+	/* Wait until Self-Refresh mode is enabled */
+	FMC_BUSY_WAIT();
+
+	memcpy((void*)SOC_RAM_BUFFER_BASE, (void*)src, size);
+
+	/*
+	 * Precharge according to chip requirement, page 12.
+	 */
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE;
+
+	FMC_BUSY_WAIT();
+
+	STM32_SDRAM_FMC->sdcmr = FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL;
+
+	/* tRFC delay */
+	udelay(60);
+
+	/* Are you still busy? */
+	FMC_BUSY_WAIT();
+
+	memcpy((void*)dst, (void*)SOC_RAM_BUFFER_BASE, size);
+
+	ret = size;
+
+out:
+	return ret;
+}
+
+/*
+ * Read from NOR and write into SDRAM
+ * See errata 2.8.7.
+ */
+int nor_sdram_bufcopy(ulong dst, ulong src, ulong size)
+{
+	int ret = 0;
+	ulong copysize = 0;
+
+	while(size) {
+		copysize = min(size, SOC_RAM_BUFFER_SIZE);
+
+		if ((ret = nor_sdram_bufcopy_onebuf(dst, src, copysize)) <= 0)
+			goto done;
+
+		dst += min(size, SOC_RAM_BUFFER_SIZE);
+		src += min(size, SOC_RAM_BUFFER_SIZE);
+		size -= min(size, SOC_RAM_BUFFER_SIZE);
+	}
+
+done:
+	return ret;
+}
+
+/*
+ * bufcopy: copy content of a NOR flash into SDRAM through SRAM buffer
+ */
+int do_bufcopy(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	ulong dst;
+	ulong src;
+	ulong size;
+	int ret = 0;
+
+	/*
+	 * Check that at least the destination is specified
+	 */
+	if (argc != 4) {
+		printf("%s: dst src size\n", (char *) argv[0]);
+		goto Done;
+	}
+
+	/*
+	 * Parse the command arguments
+	 */
+	dst = simple_strtoul(argv[1], NULL, 16);
+	src = simple_strtoul(argv[2], NULL, 16);
+	size = simple_strtoul(argv[3], NULL, 16);
+
+	if (dst < CONFIG_SYS_RAM_BASE) {
+		printf("%s: dst is outside SDRAM\n", (char *) argv[0]);
+		goto Done;
+	}
+
+	printf("%s: Doing bufcopy, please wait ...\n", (char *) argv[0]);
+
+	/*
+	 * Copy the buffer to the destination.
+	 */
+	if ((ret = nor_sdram_bufcopy(dst, src, size)) < 0) {
+		printf("%s: nor_sdram_bufcopy failed: %d\n",
+						(char *) argv[0], ret);
+		goto Done;
+	}
+
+Done:
+	return ret;
+}
+
+U_BOOT_CMD(
+	stmbufcopy,	5,		0,	do_bufcopy,
+	"copy from NOR flash into SDRAM through SRAM buf",
+	"dst src size"
+);

cpu/arm_cortexm3/stm32/fsmc.c

@@ -151,6 +151,9 @@ int fsmc_nor_psram_init(u32 cs, u32 bcr, u32 btr, u32 bwtr)
 	 */
 	STM32_RCC->ahb3enr |= STM32_RCC_ENR_FSMC;
 
+	/* Errata 2.1.6 */
+	__asm__ __volatile__ ("dsb" : : : "memory");
+
 	/*
 	 * Fake BCR read; if don't do this, then BCR remains configured
 	 * with defaults.

drivers/mtd/cfi_flash.c

@@ -136,6 +136,12 @@ u8 flash_read8(void *addr)__attribute__((weak, alias("__flash_read8")));
 u16 flash_read16(void *addr)__attribute__((weak, alias("__flash_read16")));
 u32 flash_read32(void *addr)__attribute__((weak, alias("__flash_read32")));
 u64 flash_read64(void *addr)__attribute__((weak, alias("__flash_read64")));
+
+# ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
+u32 flash_write_buffer(void *src, void *dst, int cnt, int portwidth)__attribute__((weak, alias("__flash_write_buffer")));
+u32 flash_check_flag(void *src, void *dst, int cnt, int portwidth)__attribute__((weak, alias("__flash_check_flag")));
+# endif
+
 #else
 #define flash_write8	__flash_write8
 #define flash_write16	__flash_write16
@@ -145,6 +151,11 @@ u64 flash_read64(void *addr)__attribute__((weak, alias("__flash_read64")));
 #define flash_read16	__flash_read16
 #define flash_read32	__flash_read32
 #define flash_read64	__flash_read64
+
+# ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
+#  define flash_write_buffer	__flash_write_buffer
+#  define flash_check_flag	__flash_check_flag
+# endif
 #endif
 
 /*-----------------------------------------------------------------------
@@ -761,6 +772,76 @@ static int flash_write_cfiword (flash_info_t * info, ulong dest,
 
 #ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
 
+u32 __flash_check_flag(void *src, void *dst, int cnt, int portwidth)
+{
+	int flag = 0;
+
+	while ((cnt-- > 0) && (flag == 0)) {
+		switch (portwidth) {
+		case FLASH_CFI_8BIT:
+			flag = ((flash_read8(dst) & flash_read8(src)) ==
+				flash_read8(src));
+			src += 1, dst += 1;
+			break;
+		case FLASH_CFI_16BIT:
+			flag = ((flash_read16(dst) & flash_read16(src)) ==
+				flash_read16(src));
+			src += 2, dst += 2;
+			break;
+		case FLASH_CFI_32BIT:
+			flag = ((flash_read32(dst) & flash_read32(src)) ==
+				flash_read32(src));
+			src += 4, dst += 4;
+			break;
+		case FLASH_CFI_64BIT:
+			flag = ((flash_read64(dst) & flash_read64(src)) ==
+				flash_read64(src));
+			src += 8, dst += 8;
+			break;
+		}
+	}
+
+	return flag;
+}
+
+
+u32 __flash_write_buffer(void *src, void *dst, int cnt, int portwidth)
+{
+	int retcode = 0;
+
+	switch (portwidth) {
+	case FLASH_CFI_8BIT:
+		while (cnt-- > 0) {
+			flash_write8(flash_read8(src), dst);
+			src += 1, dst += 1;
+		}
+		break;
+	case FLASH_CFI_16BIT:
+		while (cnt-- > 0) {
+			flash_write16(flash_read16(src), dst);
+			src += 2, dst += 2;
+		}
+		break;
+	case FLASH_CFI_32BIT:
+		while (cnt-- > 0) {
+			flash_write32(flash_read32(src), dst);
+			src += 4, dst += 4;
+		}
+		break;
+	case FLASH_CFI_64BIT:
+		while (cnt-- > 0) {
+			flash_write64(flash_read64(src), dst);
+			src += 8, dst += 8;
+		}
+		break;
+	default:
+		retcode = ERR_INVAL;
+		goto out;
+	}
+
+out:
+	return retcode;
+}
 static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
 				  int len)
 {
@@ -769,7 +850,6 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
 	int retcode;
 	void *src = cp;
 	void *dst = (void *)dest;
-	void *dst2 = dst;
 	int flag = 0;
 	uint offset = 0;
 	unsigned int shift;
@@ -795,36 +875,12 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
 
 	cnt = len >> shift;
 
-	while ((cnt-- > 0) && (flag == 0)) {
-		switch (info->portwidth) {
-		case FLASH_CFI_8BIT:
-			flag = ((flash_read8(dst2) & flash_read8(src)) ==
-				flash_read8(src));
-			src += 1, dst2 += 1;
-			break;
-		case FLASH_CFI_16BIT:
-			flag = ((flash_read16(dst2) & flash_read16(src)) ==
-				flash_read16(src));
-			src += 2, dst2 += 2;
-			break;
-		case FLASH_CFI_32BIT:
-			flag = ((flash_read32(dst2) & flash_read32(src)) ==
-				flash_read32(src));
-			src += 4, dst2 += 4;
-			break;
-		case FLASH_CFI_64BIT:
-			flag = ((flash_read64(dst2) & flash_read64(src)) ==
-				flash_read64(src));
-			src += 8, dst2 += 8;
-			break;
-		}
-	}
+	flag = flash_check_flag (src, dst, cnt, info->portwidth);
 	if (!flag) {
 		retcode = ERR_NOT_ERASED;
 		goto out_unmap;
 	}
 
-	src = cp;
 	sector = find_sector (info, dest);
 
 	switch (info->vendor) {
@@ -844,29 +900,10 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
 			 * the port */
 			cnt = len >> shift;
 			flash_write_cmd (info, sector, 0, cnt - 1);
-			while (cnt-- > 0) {
-				switch (info->portwidth) {
-				case FLASH_CFI_8BIT:
-					flash_write8(flash_read8(src), dst);
-					src += 1, dst += 1;
-					break;
-				case FLASH_CFI_16BIT:
-					flash_write16(flash_read16(src), dst);
-					src += 2, dst += 2;
-					break;
-				case FLASH_CFI_32BIT:
-					flash_write32(flash_read32(src), dst);
-					src += 4, dst += 4;
-					break;
-				case FLASH_CFI_64BIT:
-					flash_write64(flash_read64(src), dst);
-					src += 8, dst += 8;
-					break;
-				default:
-					retcode = ERR_INVAL;
-					goto out_unmap;
-				}
-			}
+			retcode = flash_write_buffer (
+				src, dst, cnt, info->portwidth);
+			if (retcode)
+				goto out_unmap;
 			flash_write_cmd (info, sector, 0,
 					 FLASH_CMD_WRITE_BUFFER_CONFIRM);
 			retcode = flash_full_status_check (
@@ -887,35 +924,10 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
 		cnt = len >> shift;
 		flash_write_cmd(info, sector, offset, cnt - 1);
 
-		switch (info->portwidth) {
-		case FLASH_CFI_8BIT:
-			while (cnt-- > 0) {
-				flash_write8(flash_read8(src), dst);
-				src += 1, dst += 1;
-			}
-			break;
-		case FLASH_CFI_16BIT:
-			while (cnt-- > 0) {
-				flash_write16(flash_read16(src), dst);
-				src += 2, dst += 2;
-			}
-			break;