U-Boot failures on CM4 and Pi4-8Gb

[Matthias Brugger]

On 16/12/2020 17:20, Peter Robinson wrote:
> On Wed, Dec 16, 2020 at 4:15 PM Matthias Brugger <matthias.bgg at gmail.com> wrote:
>>
>> Hi Dave,
>>
>> On 16/12/2020 15:23, Dave Jones wrote:
>>> Hi,
>>>
>>> We've recently run across some failures with U-Boot on a couple of platforms,
>>> specifically the relatively new Pi Compute Module 4, and the Pi 4 8GB of RAM. On
>>> the CM4, U-Boot failed to identify the eMMC storage, and on the Pi 4 8GB, a
>>> crash and reset occurred when U-Boot tried to read from the boot file-system on
>>> the SD card, but only when booted with no monitor attached (attaching a monitor
>>> results in a successful boot, at least under arm64). These were with
>>> more-or-less stock rpi_4_defconfig and rpi_4_32b_defconfig configurations from
>>> v2020.10 (our local config changes bump the env-size, enable OF_BOARD, and
>>> RAW_INITRD, but that's it).
>>>
>>> I've bisected the source and figured out roughly the commits responsible; for
>>> the CM4 eMMC case it's the enabling of DMA for the SDHCI interface in c6b9fbf756.
>>>
>>> The Pi 4 8GB failure was a little more complex in that the bisection pointed to
>>> 3113c84ba2 (a merge), however that gave me a few clues to try and after a little
>>> experimenting I found that disabling CONFIG_PCI_BRCMSTB (effectively disabling
>>> the PCI driver for the platform) got things working happily again.
>>>
>>> I'm happy to submit the local patches I'm adding to the Ubuntu build to work
>>> around these, but obviously those fixes are "brute force and ignorance" patches
>>> that just disable the relevant config; would such patches be wanted, or would
>>> the community prefer to figure out the root causes in each case? I'm happy to
>>> test any patches on the relevant hardware if anyone doesn't have access to the
>>> necessary boards.
>>>
>>
>> Thanks for looking into this. I'm aware of problems booting CM4 and RPi 400 with
>> PCI. I wasn't aware that RPi4 8GB problem was related to PCI as well. Would you
>> mind to test this series, if this fixes your problems:
>> https://patchwork.ozlabs.org/user/todo/uboot/?series=220661
> 
> That's your todo list so the link doesn't work for an anonymous consumer.
> 

Right, sorry not my day today:
https://patchwork.ozlabs.org/project/uboot/list/?series=220661

Regards,
Matthias