[U-Boot] [PATCH] SPL: NOR: Add CONFIG_SPL_NOR_COPY_ENTIRE_IMAGE define to enable whole image copy from NOR

[Lukasz Majewski]

Hi Marek,

> On 12/26/2016 05:36 PM, Lukasz Majewski wrote:
> > Hi Marek,
> > 
> >> On 11/29/2016 07:18 PM, Tom Rini wrote:
> >>> On Tue, Nov 29, 2016 at 11:50:34AM +0100, Marek Vasut wrote:
> >>>> On 11/29/2016 10:11 AM, Lukasz Majewski wrote:
> >>>>> Hi Marek,
> >>>>>
> >>>>>> On 11/28/2016 10:09 PM, Lukasz Majewski wrote:
> >>>>>>> This define gives the possibility to copy entire image
> >>>>>>> (including header - e.g. u-boot.img) from NOR parallel memory
> >>>>>>> to e.g. SDRAM. The current code only supports loading the raw
> >>>>>>> binary image (the u-boot.bin).
> >>>>>>>
> >>>>>>> The legacy behavior is preserved, since other board don't
> >>>>>>> enabled this option.
> >>>>>>
> >>>>>> Sooooo, what's the usecase again ? ;-) 
> >>>>>
> >>>>> :-)
> >>>>>
> >>>>> The use case is to allow u-boot.img being loaded from Parallel
> >>>>> NOR. The current code only supports u-boot.bin.
> >>>>
> >>>> Why is u-boot.bin (or the payload) not sufficient ? Why do you
> >>>> need the header ?
> >>>
> >>> Well, the general use-case and code flow is that we load
> >>> u-boot.img (or a FIT image) and if all else fails, fall back to
> >>> assuming a .bin and a known address).
> >>>
> >> And exactly how is that whole image useful in RAM ? Sorry, I still
> >> do not see it, usually you just need the executable payload,
> >> although even that can be left in flash most of the time.
> > 
> > The use case is that I do want to boot from SD card/eMMC and NOR
> > with using u-boot.img.
> > 
> > I would like to avoid situation when for NOR I must use u-boot.bin
> > and for eMMC u-boot.img.
> > 
> > Such approach keeps things as simple as possible :-)
> 
> Oh, so it allows you to detect bitrot for the content in SPI NOR ?

I do not use SPI NOR, it is parallel NOR.

> It's a bit strange we had to use u-boot.bin with SPL there.
> 

This is how the legacy system behaves. It uses (by default) Parallel
NOR for booting (with advised/provided NOR memory timings). After doing
some measurements, it turned out that for "tunned" u-boot/SPL there
would be the best way to copy it to ram and execute it from there (just
like eMMC).

Hence, I would like to use u-boot.img in both booting scenarios.

Best regards,
Łukasz Majewski

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