Re: [flasher PATCH 2/4] Increase padding between U-Boot binary and flash image

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On Thu, Dec 05, 2013 at 03:13:00PM -0700, Stephen Warren wrote:
> From: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> The flasher currently places the flash image in RAM almost directly above
> the initial U-Boot binary location, with just a little padding/alignment
> in between. This is also where U-Boot's BSS is located, prior to U-Boot
> relocating itself to the top of RAM. Hence, if U-Boot touches its BSS, it
> will corrupt the flash image. Increase the padding between U-Boot/DT and
> the flash image to avoid this. U-Boot's BSS is roughly 300K at present.
> Make the pad size 1M to allow plenty of room for growth.
> 
> Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
>  tegra-uboot-flasher | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tegra-uboot-flasher b/tegra-uboot-flasher
> index d97b9e43aa45..06e297730112 100755
> --- a/tegra-uboot-flasher
> +++ b/tegra-uboot-flasher
> @@ -143,9 +143,9 @@ def func_flash():
>      if args.debug:
>          print 'u_boot_plus_dtb_size %d 0x%x' % (u_boot_plus_dtb_size, u_boot_plus_dtb_size)
>  
> -    # Add 32k in case size changes due to fdtput
> +    # Add 1024k to avoid U-Boot's BSS, and in case the DT size changes due to fdtput
>      # Align to 4k, so flash writes don't need a bounce buffer for DMA
> -    padded_size = (u_boot_plus_dtb_size + (32 * 1024) + (4 * 1024) - 1) & ~((4 * 1024) - 1)
> +    padded_size = (u_boot_plus_dtb_size + (1024 * 1024) + (4 * 1024) - 1) & ~((4 * 1024) - 1)

You could save a multiplication here by extracting the common factor
1024... =)

Reviewed-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

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