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

["Marcin Wojtas" <mw@semihalf.com>]

Hi,

I see Greg was dropped in the meantime.

pt., 12 cze 2020 o 10:45 Ard Biesheuvel <ard.biesheuvel@arm.com> napisał(a):
>
> On 6/12/20 12:43 AM, Mark Kettenis via Groups.Io wrote:
> > 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.
>
> Thanks Mark
>
> The struct type is defined as
>
> typedef struct {
>    UINT8   AddressSpaceId;
>    UINT8   RegisterBitWidth;
>    UINT8   RegisterBitOffset;
>    UINT8   AccessSize;
>    UINT64  Address;
> } EFI_ACPI_5_0_GENERIC_ADDRESS_STRUCTURE;
>
> so I agree that the current definition matches a UART that requires byte
> accesses on registers that are 32 bits apart.
>
> So why does FreeBSD deviate from this?

Greg, can you please explain your concerns here?

Thanks,
Marcin