Hi Marek, > On 12/29/2016 04:26 PM, Tom Rini wrote: > > On Thu, Dec 29, 2016 at 12:41:06AM +0100, Marek Vasut wrote: > >> On 12/28/2016 09:52 AM, Lukasz Majewski wrote: > >>> 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. > >> > >> Sorry, I meant parallel NOR of course. > >> > >>>> 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. > >> > >> I think I was mistaken yesterday, I don't think I understand why > >> copying the image including the header into RAM has any benefit > >> compared to copying just the image payload to RAM (and yes, we're > >> getting back to my original question). > > > > Code complexity and forward compatibility? > > This is adding code complexity, but this is not my point. > > > The general case in the SPL > > framework is that we have either a "legacy" image or a FIT image > > and we fall back to "well, just run it!". > > Well, this doesn't answer my question, because if I understand this > patch correctly, it copies the entire legacy image (incl. header) into > RAM instead of copying just the image payload (which we already do). I > don't really understand why we want to do this. Or do I misunderstand > something ?
No, you understood everything correctly. After some thoughts, I think that only payload should be copied. I'll prepare test setup and double check this patch usability by Monday. Best regards, Łukasz Majewski
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