[U-Boot] [RFC PATCH v2] sf: support chips using 4-byte addressing

Siva Durga Prasad Paladugu siva.durga.paladugu at xilinx.com
Wed Oct 19 13:50:05 CEST 2016


Hi Chris,

> -----Original Message-----
> From: U-Boot [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Chris
> Packham
> Sent: Wednesday, October 19, 2016 2:06 PM
> To: u-boot at lists.denx.de
> Cc: Jagan Teki <jteki at openedev.com>; Chris Packham
> <judge.packham at gmail.com>
> Subject: [U-Boot] [RFC PATCH v2] sf: support chips using 4-byte addressing
> 
> SPI chips with >16MB capacity use 4-byte addressing to allow accessing
> beyond 16MB. When the size of the SPI flash exceeds 16MB switch to using 4
> byte addressing.

Not all spi controllers support 4-byte addressing and hence its better not to decide 
just using spi flash device size but consider capability of driver also into account.

Thanks,
Siva

> 
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> 
> ---
> 
> Changes in v2:
> - automatically detect when 4 byte addressing is needed. This is similar
>   to how the linux kernel does the same detection
> 
>  drivers/mtd/spi/sf_internal.h |  4 ++--
>  drivers/mtd/spi/spi_flash.c   | 32 ++++++++++++++++++++++----------
>  include/spi_flash.h           |  2 ++
>  3 files changed, 26 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
> index cde4cfbf2e32..db4532849145 100644
> --- a/drivers/mtd/spi/sf_internal.h
> +++ b/drivers/mtd/spi/sf_internal.h
> @@ -25,8 +25,8 @@ enum spi_nor_option_flags {
>  	SNOR_F_USE_FSR		= BIT(1),
>  };
> 
> -#define SPI_FLASH_3B_ADDR_LEN		3
> -#define SPI_FLASH_CMD_LEN		(1 + SPI_FLASH_3B_ADDR_LEN)
> +#define SPI_FLASE_MAX_ADDR_WIDTH	4
> +#define SPI_FLASH_CMD_LEN		(1 + SPI_FLASE_MAX_ADDR_WIDTH)
>  #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
> 7f6e9ae23ea8..a3efaa129231 100644
> --- a/drivers/mtd/spi/spi_flash.c
> +++ b/drivers/mtd/spi/spi_flash.c
> @@ -22,12 +22,19 @@
> 
>  DECLARE_GLOBAL_DATA_PTR;
> 
> -static void spi_flash_addr(u32 addr, u8 *cmd)
> +static void spi_flash_addr(u32 addr, u8 *cmd, u8 addr_width)
>  {
>  	/* cmd[0] is actual command */
> -	cmd[1] = addr >> 16;
> -	cmd[2] = addr >> 8;
> -	cmd[3] = addr >> 0;
> +	if (addr_width == 4) {
> +		cmd[1] = addr >> 24;
> +		cmd[2] = addr >> 16;
> +		cmd[3] = addr >> 8;
> +		cmd[4] = addr;
> +	} else {
> +		cmd[1] = addr >> 16;
> +		cmd[2] = addr >> 8;
> +		cmd[3] = addr >> 0;
> +	}
>  }
> 
>  static int read_sr(struct spi_flash *flash, u8 *rs) @@ -357,12 +364,13 @@
> 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(erase_addr, cmd, flash->addr_width);
> 
>  		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->addr_width
> + 1,
> +					     NULL, 0);
>  		if (ret < 0) {
>  			debug("SF: erase failed\n");
>  			break;
> @@ -415,12 +423,12 @@ int spi_flash_cmd_write_ops(struct spi_flash
> *flash, u32 offset,
>  			chunk_len = min(chunk_len,
>  					(size_t)spi->max_write_size);
> 
> -		spi_flash_addr(write_addr, cmd);
> +		spi_flash_addr(write_addr, cmd, flash->addr_width);
> 
>  		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),
> +		ret = spi_flash_write_common(flash, cmd, flash->addr_width
> + 1,
>  					buf + actual, chunk_len);
>  		if (ret < 0) {
>  			debug("SF: write failed\n");
> @@ -492,7 +500,7 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash,
> u32 offset,
>  		return 0;
>  	}
> 
> -	cmdsz = SPI_FLASH_CMD_LEN + flash->dummy_byte;
> +	cmdsz = flash->addr_width + 1 + flash->dummy_byte;
>  	cmd = calloc(1, cmdsz);
>  	if (!cmd) {
>  		debug("SF: Failed to allocate cmd\n"); @@ -520,7 +528,7 @@
> int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
>  		else
>  			read_len = remain_len;
> 
> -		spi_flash_addr(read_addr, cmd);
> +		spi_flash_addr(read_addr, cmd, flash->addr_width);
> 
>  		ret = spi_flash_read_common(flash, cmd, cmdsz, data,
> read_len);
>  		if (ret < 0) {
> @@ -1154,6 +1162,10 @@ int spi_flash_scan(struct spi_flash *flash)
>  	if (flash->dual_flash & SF_DUAL_STACKED_FLASH)
>  		flash->size <<= 1;
>  #endif
> +	if (flash->size > SPI_FLASH_16MB_BOUN)
> +		flash->addr_width = 4;
> +	else
> +		flash->addr_width = 3;
> 
>  #ifdef CONFIG_SPI_FLASH_USE_4K_SECTORS
>  	/* Compute erase sector and command */ diff --git
> a/include/spi_flash.h b/include/spi_flash.h index
> be2fe3f84cb9..c65bf22aee8b 100644
> --- a/include/spi_flash.h
> +++ b/include/spi_flash.h
> @@ -39,6 +39,7 @@ struct spi_slave;
>   * @flags:		Indication of spi flash flags
>   * @size:		Total flash size
>   * @page_size:		Write (page) size
> + * @addr_width:		number of address bytes
>   * @sector_size:	Sector size
>   * @erase_size:		Erase size
>   * @bank_read_cmd:	Bank read cmd
> @@ -72,6 +73,7 @@ struct spi_flash {
> 
>  	u32 size;
>  	u32 page_size;
> +	u8 addr_width;
>  	u32 sector_size;
>  	u32 erase_size;
>  #ifdef CONFIG_SPI_FLASH_BAR
> --
> 2.10.0.479.g7c56b16
> 
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