[U-Boot] [PATCH] dfu: dfu_sf: Take the start address into account

[Stephen Warren]

On 09/23/2015 09:44 AM, Fabio Estevam wrote:
> On Wed, Sep 23, 2015 at 12:36 PM, Fabio Estevam <festevam at gmail.com> wrote:
>> On Wed, Sep 23, 2015 at 12:22 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
>>
>>> This feels wrong. The entries in the DFU list must already be
>>> sector-aligned, so there's no need for the code to round them. If the
>>> entries are not already aligned, then the aligned erase operations will
>>> erase other data, which will cause corruption.
>>
>> The start address does not need to be sector-aligned.
>>
>> In my case the SPL image needs to be placed at 0x400.
>
> Also, just to clarify: in this patch we make sure that the erase
> operation are always sector-aligned.
>
> Only the write operations can be 'shifted' due to the start address
> passed via dfu_alt_info.

So it's OK to erase the data between 0..0x400 and not replace it? Even 
if that's true in your case, it seems quite unlikely in general.

Instead, the DFU region should start and end at sector-aligned locations 
so that erasing the region doesn't negatively affect other data. If 
logical objects in your flash aren't sector aligned, then that simply 
means you need to construct a complete flash image and write the whole 
thing at once. I don't thin there's any other way to avoid corruption.