[U-Boot] [PATCH] nand: mxs_nand_spl: support use of env in SPL

[Scott Wood <scottwood@freescale.com>]

On Thu, 2015-05-14 at 08:12 -0700, Tim Harvey wrote:
> It turns out that this is needed because env_nand.c:readenv() calls
> nand_read_skip_bad, which uses the mtd layer. For SPL the
> functionality of readenv() is pretty much already in
> nand_spl_load_image() so I find if do the following (instead of making
> any changes to mxs_nand_spl.c) which allows the mtd layers to not be
> used I save 4KB in the SPL:
> 
> diff --git a/common/env_nand.c b/common/env_nand.c
> index cc7e979..97d10a2 100644
> --- a/common/env_nand.c
> +++ b/common/env_nand.c
> @@ -260,6 +260,9 @@ int saveenv(void)
>  }
>  #endif /* CMD_SAVEENV */
> 
> +#if defined(CONFIG_SPL_BUILD)
> +#define readenv(offset, buf) nand_spl_load_image(offset, CONFIG_ENV_SIZE, buf)
> +#else
>  static int readenv(size_t offset, u_char *buf)
>  {
>         size_t end = offset + CONFIG_ENV_RANGE;
> @@ -295,6 +298,7 @@ static int readenv(size_t offset, u_char *buf)
> 
>         return 0;
>  }
> +#endif /* #if defined(CONFIG_SPL_BUILD) */
> 
>  #ifdef CONFIG_ENV_OFFSET_OOB
>  int get_nand_env_oob(nand_info_t *nand, unsigned long *result)
> 
> I don't think I'm loosing any necessary functionality in the SPL by
> doing the above and it saves me 4KB in the SPL which is precious
> space.

I'd prefer a function over a macro, but OK.

readenv() itself looks like it could be greatly simplified by dropping
the loop and bad block check, since nand_read_skip_bad() handles that.

-Scott