[U-Boot] [RFC PATCH 4/4 v3] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset

[Jagan Teki]

On 1 October 2014 20:43, Stefan Roese <sr at denx.de> wrote:
> This is needed for the SoCFPGA booting from SPI NOR flash
> e.g. (N25Q256A). With these changes, the SoCrates can boot and
> re-boot (reset) from SPI NOR flash without any problems.
>
> Signed-off-by: Stefan Roese <sr at denx.de>
> Cc: Chin Liang See <clsee at altera.com>
> Cc: Dinh Nguyen <dinguyen at altera.com>
> Cc: Vince Bridgers <vbridger at altera.com>
> Cc: Marek Vasut <marex at denx.de>
> Cc: Pavel Machek <pavel at denx.de>
> Cc: Michael Trimarchi <michael at amarulasolutions.com>
> Cc: Jagannadha Sutradharudu Teki <jagannadh.teki at gmail.com>
> ---
>  drivers/mtd/spi/sf_probe.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
>
> diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
> index 4d148d1..85b2677 100644
> --- a/drivers/mtd/spi/sf_probe.c
> +++ b/drivers/mtd/spi/sf_probe.c
> @@ -355,6 +355,37 @@ static struct spi_flash *spi_flash_probe_slave(struct spi_slave *spi)
>                 }
>         }
>
> +#ifdef CONFIG_SPI_N25Q256A_RESET
> +#define CMD_RESET_ENABLE       0x66
> +#define CMD_RESET_MEMORY       0x99
> +       /*
> +        * This is needed for the SoCFPGA booting from SPI NOR flash
> +        * e.g. (N25Q256A). Additionally its necessary to change
> +        * this line in the Linux SPI NOR flash driver:
> +        *
> +        * { "n25q256a",    INFO(0x20ba19, 0, 64 * 1024,  512,
> +        *    SECT_4K | SHUTDOWN_3BYTE) },
> +        *
> +        * Add SHUTDOWN_3BYTE here.
> +        *
> +        * With these changes, the SoCrates can boot and re-boot
> +        * (reset) from SPI NOR flash without any problems.
> +        */
> +       ret = spi_flash_cmd(spi, CMD_RESET_ENABLE, NULL, 0);
> +       if (ret) {
> +               printf("SF: Failed issue reset command\n");
> +               goto err_read_id;
> +       }
> +
> +       ret = spi_flash_cmd(spi, CMD_RESET_MEMORY, NULL, 0);
> +       if (ret) {
> +               printf("SF: Failed issue reset command\n");
> +               goto err_read_id;
> +       }
> +
> +       printf("SF: Device software reset\n");
> +#endif

I have tested N25Q256A on zynq, couldn't encounter this either.
This seems to be SPI flash logic more hardwired to N25Q256A.

Any comments?

> +
>  #ifdef CONFIG_OF_CONTROL
>         if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
>                 debug("SF: FDT decode error\n");
> --
> 2.1.1
>

thanks!
-- 
Jagan.