On 2020.03.30 15:01, Ard Biesheuvel wrote:
On Mon, 30 Mar 2020 at 15:56, Pete Batard <[email protected]> wrote:
On 2020.03.30 14:20, Ard Biesheuvel wrote:
On Mon, 30 Mar 2020 at 15:12, Ard Biesheuvel <[email protected]> wrote:
On Mon, 30 Mar 2020 at 15:09, Pete Batard <[email protected]> wrote:
On 2020.03.30 14:06, Ard Biesheuvel wrote:
On Fri, 27 Mar 2020 at 14:06, Pete Batard <[email protected]> wrote:
Incidentally, this is not an [edk2-platform] patch, as the subject line
from previous mail seemed to indicate, but an [edk2] patch.
Do we have a user for this?
Yes we do. I have a pachset lined up that updates the Raspberry Pi ACPI
to 6.3, that has a dependency on this.
But does the RPi have SPE and the associated overflow interrupt?
No, but it doesn't matter since the specs indicate that SPE values can
be set to zero if unused/non-applicable.
ACPI
is designed to be backward compatible, so it is perfectly acceptable
to use the 6.2 macros in the context of a firmware implementation that
complies with 6.3.
This is what happens if you try to use EFI_ACPI_6_0_GICC_STRUCTURE_INIT
in a 6.3 context:
/usr/src/edk2/MdePkg/Include/IndustryStandard/Acpi10.h:297:33: error:
excess elements in scalar initializer [-Werror]
#define EFI_ACPI_RESERVED_BYTE 0x00
^~~~
Building ...
/usr/src/edk2/MdePkg/Library/DxeCoreHobLib/DxeCoreHobLib.inf [AARCH64]
/usr/src/edk2/EmbeddedPkg/Include/Library/AcpiLib.h:64:30: note: in
expansion of macro ‘EFI_ACPI_RESERVED_BYTE’
{EFI_ACPI_RESERVED_BYTE, EFI_ACPI_RESERVED_BYTE,
EFI_ACPI_RESERVED_BYTE} \
^~~~~~~~~~~~~~~~~~~~~~
/usr/src/edk2-platforms/Platform/RaspberryPi/AcpiTables/Madt.aslc:64:5:
note: in expansion of macro ‘EFI_ACPI_6_0_GICC_STRUCTURE_INIT’
EFI_ACPI_6_0_GICC_STRUCTURE_INIT (
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
What do you mean exactly by 'in a 6.3 context': are you trying to
statically initialize a 63 struct with the 60 macro?
Yes. I am trying to upgrade all of our ACPI tables to 6.3, on account
that (part of a commit message from the edk2-platform I have lined up):
-----------------------------------------------------------------------
Because of its widespread availability and low price, we expect the
Raspberry Pi source to be used by platform developers as a starting
point to create their own platform implementation.
As such, it makes a lot of sense to want to use the most up to date
underlying standards, even if the pay off is limited in this case,
as it may help others benefit from the latest improvements and
features brought by modern ACPI.
-----------------------------------------------------------------------
The only reason I'm sending an EDK2 patch, which I'd always rather avoid
so that edk2-platforms patches can be applied faster, is that I haven't
been able to find a way to make the existing 6.0 macros work in a 6.3
context, and I expect that this will be the case for others.
By why do we need the 6.3 context? If 6.0 can describe our platform
fully, it is actually better for compatibility to stick with it rather
than upgrade to 6.3.
See above.
I have to say that I'm a bit taken aback by the idea that, even though
we can anticipate that there will be a need for a 6.3 macro that does
initialise the SPE field, there seems to be strong reluctance to add
that macro before someone makes the case for it.
Ideally, we should update our macros the minute the specs are released,
regardless of whether we believe there's a use-case for it or not.
Regards,
/Pete
Or is there another reason you want to update the
MADT to 6.3?
I just want to fix the compilation error, as well as make sure that
folks who need the ACPI 6.3 SPE init can get it without having to spend
time waiting for an EDK2 patch to be applied.
BTW, this patch sets the size of the GICC entry to 'sizeof
(EFI_ACPI_6_0_GIC_STRUCTURE)' so it is likely that the parser will
choke on it.
The structure size hasn't changed. There were 3 reserved bytes, and now
there's one reserve byte and one 16-bit word for the SPE.
Since I actually need this patch as part of a platform update, I did
validate compilation, so, no, the parser doesn't choke on it.
I didn't mean to imply that you are being sloppy. I'd just like to
understand what the point is of all of this, given that ACPI 6.3 is
not needed to describe the RPi4
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