[yocto] how to tftp download a newer u-boot into RAM and simply execute it?

[Bruce Ashfield]

On 2016-07-06 03:14 PM, Robert P. J. Day wrote:
> On Wed, 6 Jul 2016, Chris Hallinan wrote:
>
>> Hi Robert,
>> That's not old, that's ancient in dog^HU-Boot years - LOL!
>>
>> It's been quite a while since I looked at a PPC U-Boot, but at a
>> minimum, you will need to link U-Boot to a RAM'able address.  By
>> default, I'm sure the recipe links it for the NOR addresses.  When
>> it boots from NOR it immediately relocates itself to a RAM address
>> from NOR, if memory serves.  Notice it's crashing right away, on the
>> second instruction.
>
>    i came to that conclusion ... i looked at the u-boot.srec file that
> was generated and, sure enough:
>
> S00E0000752D626F6F742E73726563C0
> S315FE00000042424242424242420606060606060606AC
> S315FE00001000000000000000000000000000000000DC
> S315FE000020A0A0A0A0A0A0A0A06060606060606060CC
> ... snip ...
>
> so definitely linked for flashing to beginning of NOR flash at
> 0xFE000000. so i suspect i could just flash it and reset and it would
> work just fine. and never mind, i found the answer i was after:
>
> http://www.denx.de/wiki/view/DULG/CanUBootBeConfiguredSuchThatItCanBeStartedInRAM
>
> i was hoodwinked into thinking it would be easy because i found this
> page:
>
> https://blackfin.uclinux.org/doku.php?id=bootloaders:u-boot:tftp_loading_files
>
> of course, that page is for the blackfin, precisely one of the
> platforms the denx page says it *can* work for. grrrrrrrrr.
>
>    so, before i commit myself to this, who's the PPC/MPC8315E-RDB
> expert on this list who can confirm a stock u-boot should flash to NOR
> and just plain run?

Kevin Hao @ Wind has been looking after the reference build for us, so
he is the best bet to know.

Bruce

>
> rday
>