Re: [edk2-devel] [edk2-platforms PATCH] Platform/RaspberryPi: Fix miniuart base address and length

["Jeremy Linton" <jeremy.linton@arm.com>]

Hi,

On 12/13/21 13:17, Andrei Warkentin via groups.io wrote:
> If I understand correctly, you want to describe the UART at 0x00215000 to be at 0x00215040.
> 
> This will break SPCR and DBG2 - so that's a regression for Windows, ESXi and possibly the NetBSDs.
> 
> I guess that's a NAK unless I misunderstood something.

Presumably the end goal is to get BT working, or are we trying to get 
the console working too?

Either way, the historical SPCR definition is less than ideal because it 
covers those AUX_IRQ/AUX_ENABLE registers which include information for 
the SPI which isn't included in the "uart" definition here. So, IMHO it 
is wrong, but its stuck that way unless we define another uart. Which if 
all we wanted it for was BT then we could just create another device 
under BCM2836 which is only the 8250 like registers. That is sorta ugly, 
but not having a standard uart is ugly too. The other ugly thing is to 
just use the address as is, and offset it by 0x40 in linux as part of 
the clock and ACPI bindings linux patch. (i've got a patch to make it 
work someone wants to bite into it. Lol).

For linux the base clock-rate is going to have to be added as a _DSD 
too. Which I assume is a large part of why it has a custom SPCR id? Put 
another way, is anyone using the extra AUX_ registers, and what else are 
people (windows/etc) "quirking" with the SPCR id?

For linux I've not particularly felt the need to fix this because I had 
BT working (although unreliably) this time last year when I was working 
on the SD/SDIO drivers, and my answer at the time was that one either 
gets a serial console using the pl011 or one gets BT with the pl011. But 
it looks like at a minimum the linux-firmware project and the brcmfmac 
firmware loader have been tweaked over the past year and getting BT 
working isn't as simple as just taking the miniuart-bt line out of 
config.txt as I have in my not particularly good notes from that time 
period.

So, while its behaving like it did when it had bad firmware, it could be 
something in the lower level firmware since attempting to roll back to 
an older firmware/kernel I had on another disk didn't immediately fix it.



> ________________________________
> From: Ard Biesheuvel <ardb@kernel.org>
> Sent: Monday, December 13, 2021 9:14 AM
> To: Adrien Thierry <athierry@redhat.com>; Andrei Warkentin <awarkentin@vmware.com>; Pete Batard <pete@akeo.ie>
> Cc: edk2-devel-groups-io <devel@edk2.groups.io>; Ard Biesheuvel <ardb+tianocore@kernel.org>; Leif Lindholm <leif@nuviainc.com>
> Subject: Re: [edk2-platforms PATCH] Platform/RaspberryPi: Fix miniuart base address and length
> 
> On Mon, 13 Dec 2021 at 15:54, Adrien Thierry <athierry@redhat.com> wrote:
>>
>> Hi Ard, Leif, Pete
>>
>> Do you have any feedback on this patch ?
>>
> 
> No objections from me but I'd like an ack from someone else as well.
> 
> 
> 
> 
> 
>