[RFC] Vocore2 MMC needs clock patches

[Mauro Condarelli]

Hi Stefan,

On 1/21/20 1:08 PM, Stefan Roese wrote:
> Hi Mauro,
>
> On 21.01.20 12:27, Mauro Condarelli wrote:
>> Thanks Weijie,
>> I made the changes You suggested.
>> I have also seen You sent a new version of Your patches.
>> Since mine are based on yours I *think* I should suspend
>> sending my VoCore2 patches till Yours are fixed and integrated
>> into master.
>>
>> @Stefan Roese: is this the right course of action?
>
> I think in the current state of Weijie's patches (v3), you can resume
> sending your VoCore2 support based on this latest patchset to the
> list. Please don't attach a patch but send it inline next time
> (git send-email) to enable review.
I will send next iteration as soon as I fix the reflash problem (see below).
 
===8<----
>> Side Question: Stefan wrote:
>>> Most of this can be done by using the
>>> RAM version now (again). There is no additional RAM booting target now
>>> any more. You can use the normal U-Boot image for this now. Please note
>>> the changes TEXT_BASE here. Its now 0x80200000.
>> This actually seems to work right if I start from my original u-boot
>> (1.1.3,
>> flashed at start of SPI NOR), but it fails if I start from a flashed
>> (at the
>> same location) u-boot-mtmips.bin
>> I *think* this happens because unpacking actually writes u-boot at
>> 0x80200000 and runs it from there, so "load usb 0:1 80200000 u-boot.bin"
>> (or equivalent) will overwrite the running u-boot and the following
>> "go ${fileaddr}" fails:
>>     ## Starting application at 0x80200000 ...
>>     <DEAD>
>
> No, U-Boot relocates itself to the end of RAM and runs from there. So
> this should work. Perhaps a cache flush is missing.
>
> I'll give it a try on my LinkIt board as well later.
Did You manage to test this?
I am currently testing loading from "paleolithic" u-boot, but I want to fix
this before I finalize VoCore2 patches.

I tried to do some manual testing enabling CONFIG_CMD_CACHE, but this
bombs with Weijie patches with:

  LD      u-boot
mipsel-linux-ld.bfd: cmd/built-in.o: in function `do_icache':
cmd/cache.c:(.text.do_icache+0x5c): undefined reference to `icache_disable'
mipsel-linux-ld.bfd: cmd/cache.c:(.text.do_icache+0x6c): undefined
reference to `icache_enable'
mipsel-linux-ld.bfd: cmd/cache.c:(.text.do_icache+0x8c): undefined
reference to `icache_status'
make: *** [Makefile:1697: u-boot] Error 1

icache seems enabled unconditionally in
arch/mips/mach-mtmips/mt7628/lowlevel_init.S::73+

I will try to add dummy functions just-to-play.

Please advise

> Thanks,
> Stefan
Regards and Many Thanks
Mauro