[U-Boot] [PATCH v3] sf: Add auto detection of 4-byte mode (vs standard 3-byte mode)

Stefan Roese sr at denx.de
Thu Oct 11 14:49:44 UTC 2018


Some SPI NOR chips only support 4-byte mode addressing. Here the default
3-byte mode does not work and leads to incorrect accesses. This patch
now reads the 4-byte mode status bit (in this case in the CR register
of the Macronix SPI NOR) and configures the SPI transfers accordingly.

This was noticed on the LinkIt Smart 7688 modul, which is equipped with
an Macronix MX25L25635F device. But this device does *NOT* support
switching to 3-byte mode via the EX4B command.

This should also work when the bootrom configures the SPI flash to
4-byte mode and runs U-Boot after this. U-Boot should dectect this
mode (if the 4-byte mode detection is available for this chip) and
use the correct OPs in this case.

Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Jagan Teki <jagan at openedev.com>
Tested-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
---
v3:
- Rebased on latest version (merge conflict because of new patches
  from Simon Glass)
- Added Tested-by tag from Simon Goldschmidt

v2:
- Integrated STMICRO 4-byte detection from Simon

 drivers/mtd/spi/sf_internal.h |   3 +-
 drivers/mtd/spi/spi_flash.c   | 131 ++++++++++++++++++++++++++++------
 include/spi_flash.h           |   5 ++
 3 files changed, 118 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 4f63cacc64..eb076401d1 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -26,7 +26,8 @@ enum spi_nor_option_flags {
 };
 
 #define SPI_FLASH_3B_ADDR_LEN		3
-#define SPI_FLASH_CMD_LEN		(1 + SPI_FLASH_3B_ADDR_LEN)
+#define SPI_FLASH_4B_ADDR_LEN		4
+#define SPI_FLASH_CMD_MAX_LEN		(1 + SPI_FLASH_4B_ADDR_LEN)
 #define SPI_FLASH_16MB_BOUN		0x1000000
 
 /* CFI Manufacture ID's */
diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
index 9230060364..b22eea2d1c 100644
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -20,12 +20,19 @@
 
 #include "sf_internal.h"
 
-static void spi_flash_addr(u32 addr, u8 *cmd)
+static void spi_flash_addr(struct spi_flash *flash, u32 addr, u8 *cmd)
 {
 	/* cmd[0] is actual command */
-	cmd[1] = addr >> 16;
-	cmd[2] = addr >> 8;
-	cmd[3] = addr >> 0;
+	if (flash->in_4byte_mode) {
+		cmd[1] = addr >> 24;
+		cmd[2] = addr >> 16;
+		cmd[3] = addr >> 8;
+		cmd[4] = addr >> 0;
+	} else {
+		cmd[1] = addr >> 16;
+		cmd[2] = addr >> 8;
+		cmd[3] = addr >> 0;
+	}
 }
 
 static int read_sr(struct spi_flash *flash, u8 *rs)
@@ -110,6 +117,72 @@ static int write_cr(struct spi_flash *flash, u8 wc)
 }
 #endif
 
+#if defined(CONFIG_SPI_FLASH_MACRONIX)
+static bool flash_in_4byte_mode_macronix(struct spi_flash *flash)
+{
+	int ret;
+	u8 cr;
+	u8 cmd;
+
+	cmd = 0x15;	/* Macronix: read configuration register RDCR */
+	ret = spi_flash_read_common(flash, &cmd, 1, &cr, 1);
+	if (ret < 0) {
+		debug("SF: fail to read config register\n");
+		return false;
+	}
+
+	/* Return true, if 4-byte mode is enabled */
+	if (cr & BIT(5))
+		return true;
+
+	return false;
+}
+#else
+static bool flash_in_4byte_mode_macronix(struct spi_flash *flash)
+{
+	return false;
+}
+#endif
+
+#if defined(CONFIG_SPI_FLASH_STMICRO)
+static bool flash_in_4byte_mode_stmicro(struct spi_flash *flash)
+{
+	int ret;
+	u8 fsr;
+	u8 cmd;
+
+	cmd = 0x70;	/* STMicro/Micron: read flag status register */
+	ret = spi_flash_read_common(flash, &cmd, 1, &fsr, 1);
+	if (ret < 0) {
+		debug("SF: fail to read config register\n");
+		return false;
+	}
+
+	/* Return true, if 4-byte mode is enabled */
+	if (fsr & BIT(0))
+		return true;
+
+	return false;
+}
+#else
+static bool flash_in_4byte_mode_stmicro(struct spi_flash *flash)
+{
+	return false;
+}
+#endif
+
+static bool flash_in_4byte_mode(struct spi_flash *flash,
+				const struct spi_flash_info *info)
+{
+	if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_MACRONIX)
+		return flash_in_4byte_mode_macronix(flash);
+
+	if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_STMICRO)
+		return flash_in_4byte_mode_stmicro(flash);
+
+	return false;
+}
+
 #ifdef CONFIG_SPI_FLASH_BAR
 /*
  * This "clean_bar" is necessary in a situation when one was accessing
@@ -314,7 +387,7 @@ int spi_flash_write_common(struct spi_flash *flash, const u8 *cmd,
 int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 {
 	u32 erase_size, erase_addr;
-	u8 cmd[SPI_FLASH_CMD_LEN];
+	u8 cmd[SPI_FLASH_CMD_MAX_LEN];
 	int ret = -1;
 
 	erase_size = flash->erase_size;
@@ -344,12 +417,13 @@ int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 		if (ret < 0)
 			return ret;
 #endif
-		spi_flash_addr(erase_addr, cmd);
+		spi_flash_addr(flash, erase_addr, cmd);
 
 		debug("SF: erase %2x %2x %2x %2x (%x)\n", cmd[0], cmd[1],
 		      cmd[2], cmd[3], erase_addr);
 
-		ret = spi_flash_write_common(flash, cmd, sizeof(cmd), NULL, 0);
+		ret = spi_flash_write_common(flash, cmd, flash->cmdlen,
+					     NULL, 0);
 		if (ret < 0) {
 			debug("SF: erase failed\n");
 			break;
@@ -373,7 +447,7 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 	unsigned long byte_addr, page_size;
 	u32 write_addr;
 	size_t chunk_len, actual;
-	u8 cmd[SPI_FLASH_CMD_LEN];
+	u8 cmd[SPI_FLASH_CMD_MAX_LEN];
 	int ret = -1;
 
 	page_size = flash->page_size;
@@ -404,15 +478,15 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 
 		if (spi->max_write_size)
 			chunk_len = min(chunk_len,
-					spi->max_write_size - sizeof(cmd));
+					spi->max_write_size - flash->cmdlen);
 
-		spi_flash_addr(write_addr, cmd);
+		spi_flash_addr(flash, write_addr, cmd);
 
 		debug("SF: 0x%p => cmd = { 0x%02x 0x%02x%02x%02x } chunk_len = %zu\n",
 		      buf + actual, cmd[0], cmd[1], cmd[2], cmd[3], chunk_len);
 
-		ret = spi_flash_write_common(flash, cmd, sizeof(cmd),
-					buf + actual, chunk_len);
+		ret = spi_flash_write_common(flash, cmd, flash->cmdlen,
+					     buf + actual, chunk_len);
 		if (ret < 0) {
 			debug("SF: write failed\n");
 			break;
@@ -469,9 +543,11 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 {
 	struct spi_slave *spi = flash->spi;
 	u8 cmdsz;
-	u32 remain_len, read_len, read_addr;
+	u64 remain_len;
+	u32 read_len, read_addr;
 	int bank_sel = 0;
 	int ret = 0;
+	int shift;
 
 	/* Handle memory-mapped SPI */
 	if (flash->memory_map) {
@@ -487,7 +563,7 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 		return 0;
 	}
 
-	cmdsz = SPI_FLASH_CMD_LEN + flash->dummy_byte;
+	cmdsz = flash->cmdlen + flash->dummy_byte;
 	u8 cmd[cmdsz];
 
 	cmd[0] = flash->read_cmd;
@@ -504,8 +580,13 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 			return log_ret(ret);
 		bank_sel = flash->bank_curr;
 #endif
-		remain_len = ((SPI_FLASH_16MB_BOUN << flash->shift) *
-				(bank_sel + 1)) - offset;
+		shift = flash->shift;
+		if (flash->in_4byte_mode)
+			shift += 8;
+
+		remain_len = (((u64)SPI_FLASH_16MB_BOUN << shift) *
+			      (bank_sel + 1)) - offset;
+
 		if (len < remain_len)
 			read_len = len;
 		else
@@ -514,7 +595,7 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 		if (spi->max_read_size)
 			read_len = min(read_len, spi->max_read_size);
 
-		spi_flash_addr(read_addr, cmd);
+		spi_flash_addr(flash, read_addr, cmd);
 
 		ret = spi_flash_read_common(flash, cmd, cmdsz, data, read_len);
 		if (ret < 0) {
@@ -1155,6 +1236,13 @@ int spi_flash_scan(struct spi_flash *flash)
 		write_sr(flash, sr);
 	}
 
+	/* Set default value for cmd length */
+	flash->cmdlen = 1 + SPI_FLASH_3B_ADDR_LEN;
+	if (flash_in_4byte_mode(flash, info)) {
+		flash->in_4byte_mode = true;
+		flash->cmdlen = 1 + SPI_FLASH_4B_ADDR_LEN;
+	}
+
 	flash->name = info->name;
 	flash->memory_map = spi->memory_map;
 
@@ -1306,14 +1394,17 @@ int spi_flash_scan(struct spi_flash *flash)
 	print_size(flash->size, "");
 	if (flash->memory_map)
 		printf(", mapped at %p", flash->memory_map);
+	if (flash->in_4byte_mode)
+		printf(" (4-byte mode)");
 	puts("\n");
 #endif
 
 #ifndef CONFIG_SPI_FLASH_BAR
-	if (((flash->dual_flash == SF_SINGLE_FLASH) &&
-	     (flash->size > SPI_FLASH_16MB_BOUN)) ||
+	if ((((flash->dual_flash == SF_SINGLE_FLASH) &&
+	      (flash->size > SPI_FLASH_16MB_BOUN)) ||
 	     ((flash->dual_flash > SF_SINGLE_FLASH) &&
-	     (flash->size > SPI_FLASH_16MB_BOUN << 1))) {
+	      (flash->size > SPI_FLASH_16MB_BOUN << 1))) &&
+	    !flash->in_4byte_mode) {
 		puts("SF: Warning - Only lower 16MiB accessible,");
 		puts(" Full access #define CONFIG_SPI_FLASH_BAR\n");
 	}
diff --git a/include/spi_flash.h b/include/spi_flash.h
index 0ec98fb55d..b5bc4a85f6 100644
--- a/include/spi_flash.h
+++ b/include/spi_flash.h
@@ -36,6 +36,8 @@ struct spi_slave;
  * @dual_flash:		Indicates dual flash memories - dual stacked, parallel
  * @shift:		Flash shift useful in dual parallel
  * @flags:		Indication of spi flash flags
+ * @in_4byte_mode:	True if flash is detected to be in 4-byte mode
+ * @cmdlen:		CMD length (3-byte vs 4-byte mode)
  * @size:		Total flash size
  * @page_size:		Write (page) size
  * @sector_size:	Sector size
@@ -69,6 +71,9 @@ struct spi_flash {
 	u8 shift;
 	u16 flags;
 
+	bool in_4byte_mode;
+	int cmdlen;
+
 	u32 size;
 	u32 page_size;
 	u32 sector_size;
-- 
2.19.1



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