Re: [PATCH v4 1/3] mtd: spi-nor: Add the SNOR_F_4B_OPCODES flag

[<Tudor.Ambarus@microchip.com>]

Hi, Boris,

On 11/29/2018 04:41 PM, Boris Brezillon wrote:
> Some flash_info entries have the SPI_NOR_4B_OPCODES flag set to let the
> core know that the flash supports 4B opcode. While this solution works
> fine for id-based caps detection, it doesn't work that well when relying
> on SFDP-based caps detection. Let's add an SNOR_F_4B_OPCODES flag so
> that the SFDP parsing code can set it when appropriate.
> 
> Reported-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> Changes in v4:
> - Set SNOR_F_4B_OPCODES flag outside of the if (mtd->size > 0x1000000)
>   block
> - Do not set SNOR_F_4B_OPCODES when BFPT_DWORD1_ADDRESS_BYTES_4_ONLY,
>   because 4byte only does not imply 4B opcodes are supported

and you got rid of the superfluous check "(JEDEC_MFR(nor->info) !=
SNOR_MFR_SPANSION)", which is good, thanks.

And I guess you should have dropped my rb tag, because I haven't reviewed v4
yet. No worries, just saying ...

> 
> Changes in v3:
> - Clear SNOR_F_4B_OPCODES flag when SFDP fails
> - Add Alexandre R-b
> 
> Changes in v2:
> - Fix the commit message
> - Fix the ->addr_width check
> - Add a comma at the end of the SNOR_F_4B_OPCODES definition
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 22 ++++++++++++----------
>  include/linux/mtd/spi-nor.h   |  1 +
>  2 files changed, 13 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index c1d9c2e50bee..98b8d9a778aa 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -3311,6 +3311,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
>  
>  		if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
>  			nor->addr_width = 0;
> +			nor->flags &= ~SNOR_F_4B_OPCODES;
>  			/* restore previous erase map */
>  			memcpy(&nor->erase_map, &prev_map,
>  			       sizeof(nor->erase_map));
> @@ -3561,9 +3562,7 @@ static int spi_nor_init(struct spi_nor *nor)
>  		}
>  	}
>  
> -	if ((nor->addr_width == 4) &&
> -	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
> -	    !(nor->info->flags & SPI_NOR_4B_OPCODES)) {
> +	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES)) {
>  		/*
>  		 * If the RESET# pin isn't hooked up properly, or the system
>  		 * otherwise doesn't perform a reset command in the boot
> @@ -3595,10 +3594,8 @@ static void spi_nor_resume(struct mtd_info *mtd)
>  void spi_nor_restore(struct spi_nor *nor)
>  {
>  	/* restore the addressing mode */
> -	if ((nor->addr_width == 4) &&
> -	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
> -	    !(nor->info->flags & SPI_NOR_4B_OPCODES) &&
> -	    (nor->flags & SNOR_F_BROKEN_RESET))
> +	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
> +	    nor->flags & SNOR_F_BROKEN_RESET)
>  		set_4byte(nor, false);
>  }
>  EXPORT_SYMBOL_GPL(spi_nor_restore);
> @@ -3750,6 +3747,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	if (info->flags & SPI_NOR_NO_FR)
>  		params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
>  
> +	if (info->flags & SPI_NOR_4B_OPCODES ||
> +	    (JEDEC_MFR(info) == SNOR_MFR_SPANSION && mtd->size > SZ_16M))
> +		nor->flags |= SNOR_F_4B_OPCODES;
> +

you are potentially overwriting the SNOR_F_4B_OPCODES that may be set in SFDP. I
suggest to set SNOR_F_4B_OPCODES flag inside of the "if (mtd->size > 0x1000000)"
block.

>  	/*
>  	 * Configure the SPI memory:
>  	 * - select op codes for (Fast) Read, Page Program and Sector Erase.
> @@ -3768,13 +3769,14 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>  	} else if (mtd->size > 0x1000000) {
>  		/* enable 4-byte addressing if the device exceeds 16MiB */
>  		nor->addr_width = 4;
> -		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> -		    info->flags & SPI_NOR_4B_OPCODES)
> -			spi_nor_set_4byte_opcodes(nor);
>  	} else {
>  		nor->addr_width = 3;
>  	}
>  
> +	if (nor->addr_width == 4 &&
> +	    nor->flags & SNOR_F_4B_OPCODES)

the conditions fit in a single line

Cheers,
ta