[edk2-devel] Additional configuration options on Armada/Cn913x
Marcin Wojtas
mw at semihalf.com
Fri Jun 12 15:07:21 UTC 2020
Hi,
I see Greg was dropped in the meantime.
pt., 12 cze 2020 o 10:45 Ard Biesheuvel <ard.biesheuvel at 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 at unrelenting.technology wrote:
> >
> > June 11, 2020 4:19 PM, "Ard Biesheuvel" <ard.biesheuvel at 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
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