Re: [edk2-devel] Additional configuration options on Armada/Cn913x

["Mark Kettenis" <mark.kettenis@xs4all.nl>]

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On Thu, Jun 11, 2020 at 04:17 PM, Ard Biesheuvel wrote:

> 
> On 6/11/20 4:07 PM, greg@unrelenting.technology wrote:
> 
>> June 11, 2020 4:19 PM, "Ard Biesheuvel" <ard.biesheuvel@arm.com> wrote:
>> 
>> 
>>> On 6/5/20 5:19 PM, Marcin Wojtas via groups.io wrote:
>>> 
>>> 
>>>> Hi,
>>>> I'd like to ask for comments before I develop the actual code - >
>>>> currently we have 2 workarounds
>>>> done specifically for Linux:
>>>> a. ECAM shift in PCIE
>>>> b. SPCR address space definition
>>> 
>>> What does this mean?
>> 
>> The SPCR in upstream edk2 is set up to work around some Linux weirdness
>> (?) and I have to do this:
>> 
>> https://github.com/myfreeweb/edk2-platforms/commit/74ec98a6498e78d2ae6c861db88487bf75f2e1a1
>> 
>> 
>> to make it work on FreeBSD.
> 
> Surely, they can't both be correct. Marcin?
> 
> 

Assuming the serial port on Armada/Cn911x is the same as on Armada8k, the following DT properties would be applicable:

reg-shift = <2>;
reg-io-width = <1>

which means the registers are spaced 32-bits apart but have to be accessed using 8-bit load/store instructions.  I'd say that
means that the ACPI Generic Address Space should have RegisterBitWidth set to 32 and AccessSize set to BYTE.
In other words, I think that the current:

#define MV_UART_AS32(Address) { EFI_ACPI_5_0_SYSTEM_MEMORY, 32, 0, EFI_ACPI_5_0_BYTE, Address }

is correct.  That certainly is what works for OpenBSD.

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