sf: Add auto detection of 4-byte mode (vs standard 3-byte mode)

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 <[email protected]>

Cc Jagan Teki <[email protected]>

Cc Simon Goldschmidt <[email protected]>

---
Please note that this patch replaces this one:

[PATCH] sf: Add SPI_FLASH_4BYTE_MODE_ONLY option to support 4-byte mode

which introduced a CONFIG option to enable this 4-byte mode. In discussion with Simon we agreed, that an auto detection would be much better. Hence this new version now.

  drivers/mtd/spi/sf_internal.h |  3 +-
  drivers/mtd/spi/spi_flash.c   | 94 +++++++++++++++++++++++++++--------
  include/spi_flash.h           |  5 ++
  3 files changed, 81 insertions(+), 21 deletions(-)

drivers/mtd/spi/sf_internal.h +2 -1

index 4f63cacc64..eb076401d1 100644
@@ -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 */

drivers/mtd/spi/spi_flash.c +11 -4

index c159124259..357b4f2422 100644
@@ -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)

drivers/mtd/spi/spi_flash.c +9 -0

+{
+	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");

drivers/mtd/spi/spi_flash.c +27 -13

+static bool flash_in_4byte_mode(struct spi_flash *flash)
+{
+	return false;
+}
+#endif
+
  #ifdef CONFIG_SPI_FLASH_BAR
  /*
   * This "clean_bar" is necessary in a situation when one was accessing

@@ -314,7 +348,7 @@ 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 +378,13 @@ 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 +408,7 @@ 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 +439,15 @@ 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 +504,11 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
  {
  	struct spi_slave *spi = flash->spi;
  	u8 *cmd, cmdsz;
-	u32 remain_len, read_len, read_addr;
+	u64 remain_len;
+	u32 read_len, read_addr;
  	int bank_sel = 0;
  	int ret = -1;
+	int shift;
 
  	/* Handle memory-mapped SPI */
  	if (flash->memory_map) {

@@ -487,7 +524,7 @@ 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;
  	cmd = calloc(1, cmdsz);
  	if (!cmd) {
  		debug("SF: Failed to allocate cmd\n");

@@ -508,8 +545,13 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
  			return 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

@@ -518,7 +560,7 @@ 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) {

@@ -1160,6 +1202,15 @@ int spi_flash_scan(struct spi_flash *flash)
  		write_sr(flash, sr);

drivers/mtd/spi/spi_flash.c +7 -3

+
  	flash->name = info->name;
  	flash->memory_map = spi->memory_map;
 

@@ -1311,14 +1362,17 @@ 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");
  	}

include/spi_flash.h +5 -0

index 0ec98fb55d..b5bc4a85f6 100644
@@ -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;

Quoted 11 lines · Stefan Roese

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

S/dectect/detect/

Quoted 6 lines

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 <[email protected]>

Cc Jagan Teki <[email protected]>

Cc Simon Goldschmidt <[email protected]>

I've successfully tested this on my socfpga_cyclone5 board. But I had to implement the detection for 'stmicro' flash. See below.

Quoted 57 lines

---
Please note that this patch replaces this one:

[PATCH] sf: Add SPI_FLASH_4BYTE_MODE_ONLY option to support 4-byte mode

which introduced a CONFIG option to enable this 4-byte mode. In discussion with Simon we agreed, that an auto detection would be much better. Hence this new version now.

   drivers/mtd/spi/sf_internal.h |  3 +-
   drivers/mtd/spi/spi_flash.c   | 94 +++++++++++++++++++++++++++--------
   include/spi_flash.h           |  5 ++
   3 files changed, 81 insertions(+), 21 deletions(-)

drivers/mtd/spi/sf_internal.h +2 -1

index 4f63cacc64..eb076401d1 100644
@@ -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 */

drivers/mtd/spi/spi_flash.c +11 -4

index c159124259..357b4f2422 100644
@@ -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)

drivers/mtd/spi/spi_flash.c static int write_cr(struct spi_flash *flash, u8 wc) · line 121

Quoted 5 lines

drivers/mtd/spi/spi_flash.c +2 -0

@@ -110,6 +117,33 @@ static int write_cr(struct spi_flash *flash, u8 wc)
   }
   #endif
 
+#if defined(CONFIG_SPI_FLASH_MACRONIX)
+static bool flash_in_4byte_mode(struct spi_flash *flash)

I renamed this function 'flash_in_4byte_mode_macronix()' as the current generic function name gives me name clashes when compiling with MACRONIX and STMICRO enabled, see below.

Quoted 9 lines

drivers/mtd/spi/spi_flash.c +9 -0

+{
+	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");

drivers/mtd/spi/spi_flash.c static int write_cr(struct spi_flash *flash, u8 wc) · line 140

Quoted 10 lines

drivers/mtd/spi/spi_flash.c +10 -0

+		return false;
+	}
+
+	/* Return true, if 4-byte mode is enabled */
+	if (cr & BIT(5))
+		return true;
+
+	return false;
+}
+#else

Here, I've added this function for STMICRO:
    #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;
          }

          printf("flash_in_4byte_mode_stmicro(): fsr: 0x%02x\n", fsr);
          /* Return true, if 4-byte mode is enabled */
          if (fsr & BIT(0)) {
              return true;
          }

          return false;
      }
      #endif

Quoted 112 lines

drivers/mtd/spi/spi_flash.c +27 -13

+static bool flash_in_4byte_mode(struct spi_flash *flash)
+{
+	return false;
+}
+#endif
+
   #ifdef CONFIG_SPI_FLASH_BAR
   /*
    * This "clean_bar" is necessary in a situation when one was accessing

@@ -314,7 +348,7 @@ 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 +378,13 @@ 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 +408,7 @@ 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 +439,15 @@ 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 +504,11 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
   {
   	struct spi_slave *spi = flash->spi;
   	u8 *cmd, cmdsz;
-	u32 remain_len, read_len, read_addr;
+	u64 remain_len;
+	u32 read_len, read_addr;
   	int bank_sel = 0;
   	int ret = -1;
+	int shift;
 
   	/* Handle memory-mapped SPI */
   	if (flash->memory_map) {

@@ -487,7 +524,7 @@ 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;
   	cmd = calloc(1, cmdsz);
   	if (!cmd) {
   		debug("SF: Failed to allocate cmd\n");

@@ -508,8 +545,13 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
   			return 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

@@ -518,7 +560,7 @@ 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) {

@@ -1160,6 +1202,15 @@ int spi_flash_scan(struct spi_flash *flash)
   		write_sr(flash, sr);

drivers/mtd/spi/spi_flash.c int spi_flash_scan(struct spi_flash *flash) · line 1212

Quoted 10 lines

drivers/mtd/spi/spi_flash.c +8 -0

   	}
 
+	/* Set default value for cmd length */
+	flash->cmdlen = 1 + SPI_FLASH_3B_ADDR_LEN;
+	if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_MACRONIX) {
+		if (flash_in_4byte_mode(flash)) {
+			flash->in_4byte_mode = true;
+			flash->cmdlen = 1 + SPI_FLASH_4B_ADDR_LEN;
+		}
+	}

And here, I inserted:
    #if defined(CONFIG_SPI_FLASH_STMICRO)
        if (JEDEC_MFR(info) == SPI_FLASH_CFI_MFR_STMICRO) { if (flash_in_4byte_mode_stmicro(flash)) { flash->in_4byte_mode = true; flash->cmdlen = 1 + SPI_FLASH_4B_ADDR_LEN; }
        }
    #endif

After that, it works fine. I'd probably always call 'flash_in_4byte_mode()' and implement the vendor check in that function to make 'spi_flash_scan()' easier to read...

I'd be happy if you could integrate this into your patch as a v2!