[U-Boot] SPL Dfu update

[Michael Trimarchi]

Hi Tom

On Wed, Oct 30, 2013 at 8:33 PM, Tom Rini <trini at ti.com> wrote:
> On Wed, Oct 30, 2013 at 03:34:45PM +0100, Michael Trimarchi wrote:
>> Hi
>>
>> On Wed, Oct 30, 2013 at 3:24 PM, Stefano Babic <sbabic at denx.de> wrote:
>> > Hi Otavio,
>> >
>> > On 30/10/2013 15:19, Otavio Salvador wrote:
>> >
>> >>> OMAP4/3 can boot over the otg, so you can send MLO and let it wait for the
>> >>> second stage boot. We have already SPL USBETH in u-boot but in production
>> >>> otg flashing can be very useful. Think SPL as a differently configured U-BOOT
>> >>> doesn't change the problem but yes it's a nice idea.
>> >>
>> >> But you'd usually want to have an 'upgrade mode' which allows DFU to
>> >> run. In this case, this could be done using complete U-Boot instead of
>> >> SPL, no? In case customer needs a slim version of it, it could be
>> >> accomplished using a specific config and having:
>> >>
>> >> SPL
>> >> Update mode U-Boot (normal U-Boot with less features)
>> >> Complete U-Boot (interactive and like)
>> >>
>> >> or am I missing something?
>> >
>> >
>> > Right, I agree completely with you.
>> >
>> > That's the reason I do not understand why we have to push DFU into SPL.
>> > Maybe we both are missing something.
>>
>> It's simple:
>>
>> - first stage boot can be sent over the otg
>> - using dfu to flash the u-boot.img, kernel .. etc
>>
>> dfu is another way to upload and write second stage or what you want. I don't
>> see the point to don't have this option. We have merged USBETH spl support
>> and dfu is more useful.
>>
>> ./usb_load MLO.flash
>> ./dfu-util ... MLO
>> ./dfu-util ... u.boot.img
>> ..
>> ./dfu-util -R
>
> Right.  The point of USBETH is to continue the flow from ROM in cases
> where we're already sending the initial payload this way.  It would be
> analogous to adding support for the USB mode omap3+ support to SPL so
> that you do:
> ./usb_load MLO.flash u-boot-flash.img
> ./dfu-util ... MLO
> ..
> ./dfu-util -R
>
> All of that said, I wouldn't mind seeing how the code to make a DFU loop
> looks, but you're likely to run into the problem of (per Wolfgang) SPL
> needing to move stack pointerinto DDR once DDR is up so that you have
> environment, and all of the other big stack users functional.

The stack pointer can be moved using the
CONFIG_SPL_RELOC_STACK

I need to give a try but dfu is more standard then send MLO and then move
to a different protocol. What tool are you using to send MLO + u-boot.img
in SPLETH way now?

Michael

>
> --
> Tom