| Message ID | 20230201113603.293758-7-miquel.raynal@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mtd: spi-nor: read while write support | expand |
Hi, Miquel! On 2/1/23 11:36, Miquel Raynal wrote: > Introduce a new (no SFDP) flag for the feature that we are about to > support: Read While Write. This means, if the chip has several banks and > supports RWW, once a page of data to write has been transferred into the > chip's internal SRAM, another read operation happening on a different > bank can be performed during the tPROG delay. > > Adding this new flag involves enlarging the no_sfdp_flags variable to 16 > bits. > I've just skimmed over jesd216 - f version, and indeed it seems that reads while write support is not covered by the standard. no_sfdp_flags is not a good place to add this flag, because there can be flashes that both support SFDP and RWW support. Please move this flag in info->flags. BTW, does you flash define SFDP table(s)? You can dump the tables via sysfs, here's an example: https://lore.kernel.org/linux-mtd/20230203044853.23513-1-Takahiro.Kuwano@infineon.com/ Cheers, ta
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h index 888a08c37d8c..aebd92f4884f 100644 --- a/drivers/mtd/spi-nor/core.h +++ b/drivers/mtd/spi-nor/core.h @@ -473,6 +473,7 @@ struct spi_nor_fixups { * SPI_NOR_OCTAL_READ: flash supports Octal Read. * SPI_NOR_OCTAL_DTR_READ: flash supports octal DTR Read. * SPI_NOR_OCTAL_DTR_PP: flash supports Octal DTR Page Program. + * SPI_NOR_RWW: flash supports reads while write. * * @fixup_flags: flags that indicate support that can be discovered via SFDP * ideally, but can not be discovered for this particular flash @@ -514,7 +515,7 @@ struct flash_info { #define SPI_NOR_NO_FR BIT(8) #define SPI_NOR_QUAD_PP BIT(9) - u8 no_sfdp_flags; + u16 no_sfdp_flags; #define SPI_NOR_SKIP_SFDP BIT(0) #define SECT_4K BIT(1) #define SPI_NOR_DUAL_READ BIT(3) @@ -522,6 +523,7 @@ struct flash_info { #define SPI_NOR_OCTAL_READ BIT(5) #define SPI_NOR_OCTAL_DTR_READ BIT(6) #define SPI_NOR_OCTAL_DTR_PP BIT(7) +#define SPI_NOR_RWW BIT(8) u8 fixup_flags; #define SPI_NOR_4B_OPCODES BIT(0)
Introduce a new (no SFDP) flag for the feature that we are about to support: Read While Write. This means, if the chip has several banks and supports RWW, once a page of data to write has been transferred into the chip's internal SRAM, another read operation happening on a different bank can be performed during the tPROG delay. Adding this new flag involves enlarging the no_sfdp_flags variable to 16 bits. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> --- drivers/mtd/spi-nor/core.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)