[U-Boot] [PATCHv3] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset

[Jagan Teki]

On 10 May 2015 at 16:19, Pavel Machek <pavel at denx.de> wrote:
> On Sun 2015-05-10 11:15:41, Pavel Machek wrote:
> Add reset for N25Q256A SPI NOR, as U-Boot SPL 2013-socfpga (only
> version working on that board) sets 4-byte addressing mode.
>
> Signed-off-by: Pavel Machek <pavel at denx.de>
>
> ---
> Diff to v3: Marek insists this is Micron specific, so lets rename the
> config option.
>
> diff --git a/README b/README
> index ee65fdb..69f9e5b 100644
> --- a/README
> +++ b/README
> @@ -2775,6 +2775,10 @@ CBFS (Coreboot Filesystem) support
>                 Timeout for waiting until spi transfer completed.
>                 default: (CONFIG_SYS_HZ/100)     /* 10 ms */
>
> +               CONFIG_SPI_MICRON_RESET
> +               Reset SPI NOR flash. Needed when preloader sets it to 4-byte
> +               mode, for example.
> +
>  - FPGA Support: CONFIG_FPGA
>
>                 Enables FPGA subsystem.
> diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
> index 201471c..6b39ce8 100644
> --- a/drivers/mtd/spi/sf_probe.c
> +++ b/drivers/mtd/spi/sf_probe.c
> @@ -347,6 +348,28 @@ int spi_flash_probe_slave(struct spi_slave *spi, struct spi_flash *flash)
>                 }
>         }
>
> +#ifdef CONFIG_SPI_MICRON_RESET
> +#define CMD_RESET_ENABLE 0x66
> +#define CMD_RESET_MEMORY 0x99
> +       /*
> +        * This is needed for the SoCFPGA booting from SPI NOR flash
> +        * e.g. (MICRON), as U-Boot SPL 2013-socfpga (only version
> +        * working on that board) sets 4-byte addressing mode.
> +        */
> +       ret = spi_flash_cmd(spi, CMD_RESET_ENABLE, NULL, 0);
> +       if (ret) {
> +               printf("SF: Failed issue enable 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
>  #ifdef CONFIG_OF_CONTROL
>         if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
>                 debug("SF: FDT decode error\n");
>

As per my early comments on this thread, I'm not happy with this approach of
being added flash specific in generic code by simply added like this.

I encounter similar issue before and I simply reverted [1]
http://git.denx.de/?p=u-boot.git;a=commit;h=122d805fd4bd478bb83536348291d34ae648364b

Please think in a different perceptive like adding any flags to specific vendor
with specific part, but that also require proper tested.

thanks!
-- 
Jagan Teki,
Openedev.