[U-Boot] [PATCH v3 17/17] sf: Add Flag status register polling support

[Simon Glass]

Hi Jagan,

On Tue, Jun 11, 2013 at 12:23 PM, Jagannadha Sutradharudu Teki <
jagannadha.sutradharudu-teki at xilinx.com> wrote:

> Flag status register polling is required for micron 512Mb flash
> devices onwards, for performing erase/program operations.
>
> Like polling for WIP(Write-In-Progress) bit in read status register,
> spi_flash_cmd_wait_ready will poll for PEC(Program-Erase-Control)
> bit in flag status register.
>
> Signed-off-by: Jagannadha Sutradharudu Teki <jaganna at xilinx.com>

---
> Changes for v3:
>         - define the flag status code on CONFIG_SPI_FLASH_STMICRO
> Changes for v2:
>         - none
>
>  drivers/mtd/spi/spi_flash.c          | 16 +++++++++++++---
>  drivers/mtd/spi/spi_flash_internal.h |  2 ++
>  2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
> index bb37f54..4f97fab0 100644
> --- a/drivers/mtd/spi/spi_flash.c
> +++ b/drivers/mtd/spi/spi_flash.c
> @@ -200,12 +200,22 @@ int spi_flash_cmd_wait_ready(struct spi_flash
> *flash, unsigned long timeout)
>         unsigned long timebase;
>         int ret;
>         u8 status;
> +       u8 check_status = 0x0;
>         u8 poll_bit = STATUS_WIP;
>         u8 cmd = CMD_READ_STATUS;
>
> +#ifdef CONFIG_SPI_FLASH_STMICRO
> +       if (flash->size >= 0x4000000) {
> +               poll_bit = STATUS_PEC;
> +               check_status = poll_bit;
> +               cmd = CMD_FLAG_STATUS;
> +       }
> +#endif
> +
>

Similarly to the bank addressing I think this might be better done as a
'poll method' rather than a hack for a particular flash type.

Also I worry that in a system with more than one type of flash, this code
will fire for all flash types.

Regards,
Simon