[PATCH v2 0/3] rpi5: initial support

[Dmitry Malkin]

Hi guys,

First of all, thank you for all your reviews. I hope I can answer all
your questions here. If I forget something please let me know.

I don't have much experience with arm/arm64 and I don't have previous
experience with u-boot and contributing to it. So please guide me for
next steps.

Also I don't think it makes sense to expect all devices or any device
may/should work after initial boot support. I would suggest going with
small steps and talking about gfx/usb/net/mmc in dedicated patchsets
after initial support is being merged.

> Could this be the title for the patch, "initial support" is fine for
> the cover letter, but doesn't really out line what this specific patch
> actually does.
Can confirm. My bad. Will fix it in the next patchset.

>> includes:
>> * 1GB of RAM (from 4GB or 8GB total)
>> * VPU memory interface
>> * SOC range (main peripherals)

> Could you include details where this information came from as well please?
By looking into FDT for memory, framebuffer, and soc nodes. I can add
this info in v3.


> When you say it doesn't work, does it just not output display or does
> the device lock up and you need to disable it?
There are artifacts on the screen and the system locks up.


> For the rpi4 it was as simple as adding a new compatible [1] for the
> rev6 of the IP block as for the bits that we use in U-Boot nothing
> changed, but the kernel changes for the rev7 that's in the RPi5 needed
> updating registers [2] so I'm not sure if we're going to need to do
> more for this or not.
I've tried it by playing with "simple-fb" and with "bcm2712-hdmi0".
And no luck. Still visible artifacts on the screen. I see valid debug
output from bcm2835_video_probe() so the mailbox for set/get
base/resolution/pitch/stride works. But still observe the same issue
with artifacts and lock up. FYI by default the probing starts due to
"bcm2708-fb".


> Might be worth looking to see if there's changes in the kernel for
> this. In an initial look I didn't see any changes to their kernel
> here.
I don't see any changes either. I'm not able to find any official
confirmation. But most of 'tags' work except two or three. And all of
them have response code 0x8000_0001. And FDT contains new info
compared to old versions (for these tags). Which leads to the
conclusion they are deprecated.


> We probably need a patch to the identifier too similar to the following:
> https://source.denx.de/u-boot/u-boot/-/commit/5e7e6619c85c090f6b62685a9d90f748f1729d12
Honestly I didn't get the reason/goal besides old/new scheme except
there is a final print:
> printf("RPI %s (0x%x)\n", model->name, revision);
which is kind of simular to my:
> printf("FW FDT model : %s\n", fdt_model);

Besides parsing the "Raspberry Pi 5 Model B Rev 1.0" string to get
revision from it? Format is unknown and nobody knows what will be
changed. Will it be "Raspberry Pi 5 Model B Rev 1.0a" or Raspberry Pi
5 Model B Rev 1.01"? I don't know. If it's really needed then I would
suggest parsing OTP to get precise info with known format.

P.S.: Please let me know if I answered all the questions so I can send v3.

Regards,
Dmitry