[U-Boot] [PATCH] sf: Enable FSR polling on N25Q256(A)

[Jagan Teki]

+ Siva

On Fri, May 25, 2018 at 1:28 AM, Marek Vasut <marex at denx.de> wrote:
> The N25Q256(A) datasheet clearly states that this device does have
> a Flag Status Register and does update FSR PEC bit 7 during Program
> and Erase cycles to indicate the cycle is in progress. Enable the
> FSR PEC bit polling on this device to prevent data corruption.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Jagan Teki <jagan at openedev.com>
> Cc: Tom Rini <trini at konsulko.com>
> ---
>  drivers/mtd/spi/spi_flash_ids.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/spi/spi_flash_ids.c b/drivers/mtd/spi/spi_flash_ids.c
> index 3b8f254ca2..fbc1bb6a5e 100644
> --- a/drivers/mtd/spi/spi_flash_ids.c
> +++ b/drivers/mtd/spi/spi_flash_ids.c
> @@ -130,8 +130,8 @@ const struct spi_flash_info spi_flash_ids[] = {
>         {"n25q64a",        INFO(0x20bb17, 0x0,  64 * 1024,   128, RD_FULL | WR_QPP | SECT_4K) },
>         {"n25q128",        INFO(0x20ba18, 0x0,  64 * 1024,   256, RD_FULL | WR_QPP) },
>         {"n25q128a",       INFO(0x20bb18, 0x0,  64 * 1024,   256, RD_FULL | WR_QPP) },
> -       {"n25q256",        INFO(0x20ba19, 0x0,  64 * 1024,   512, RD_FULL | WR_QPP | SECT_4K) },
> -       {"n25q256a",       INFO(0x20bb19, 0x0,  64 * 1024,   512, RD_FULL | WR_QPP | SECT_4K) },
> +       {"n25q256",        INFO(0x20ba19, 0x0,  64 * 1024,   512, RD_FULL | WR_QPP | E_FSR | SECT_4K) },
> +       {"n25q256a",       INFO(0x20bb19, 0x0,  64 * 1024,   512, RD_FULL | WR_QPP | E_FSR | SECT_4K) },

FSR is required to poll flag status instead of read status only from
Micron n25q512 because 512 is divided into two 256 dies so FSR is used
for polling each die. In case of n25q256 the flash is single entity
(doesn't have die concept) so there is no need to poll FSR.

This is what I understood when I add initial FSR support
0f6232801cee4f45dbdb0cec45f71172c9b617ca


Jagan.

-- 
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.