Re: [edk2-platforms][PATCH V2 0/9] Upadate the ACPI tables for RD platforms

["Pranav Madhu" <pranav.madhu@arm.com>]

Hi Ard,

Thanks for your time in reviewing this patch series. Please find my response inline.

> -----Original Message-----
> From: Ard Biesheuvel <ardb@kernel.org>
> Sent: Wednesday, April 20, 2022 1:11 PM
> To: Pranav Madhu <Pranav.Madhu@arm.com>
> Cc: edk2-devel-groups-io <devel@edk2.groups.io>; Ard Biesheuvel
> <ardb+tianocore@kernel.org>; Sami Mujawar <Sami.Mujawar@arm.com>
> Subject: Re: [edk2-platforms][PATCH V2 0/9] Upadate the ACPI tables for RD
> platforms
> 
> On Mon, 18 Apr 2022 at 13:54, Pranav Madhu <pranav.madhu@arm.com>
> wrote:
> >
> > Changes since V1:
> > - Rebased on top of latest master branch.
> > - Rebased on top of patch to remove SLC cache entries from PPTT (link
> >   for the same in edk2.groups.io is provided below)
> >
> > Arm infrastructure reference design platforms uses ACPI tables to
> > provide the hardware information to the operating system. Currently
> > the ACPI tables are aligned with ACPI v6.2 and v6.3 specification.
> > This patch series update the tables to ACPI v6.4 specificaion.
> >
> 
> Why is this necessary? By doing this, you will lose the ability to boot an OS that
> implements ACPI 6.2 but not ACPI 6.4, and so this should only be done if you are
> actually relying on a feature that was not available in ACPI 6.2. Otherwise, this
> is just pointless busywork.
> 

As per SystemReady SBBR specification, all the ACPI tables should adhere to a specific ACPI revision. At present the FADT, GTDT, MADT... tables are as per ACPI specification 6.2 and PPTT, HMAT... tables are as per specification 6.3. To achieve compliance, we need to either downgrade some tables to 6.2 or else upgrade the rest of the tables to 6.3. As a solution for this, upgrade all tables to 6.4 as this is the most recent. The effort required to bring all tables to ACPI 6.3 and 6.4 are almost same. Also, with ACPI 6.4 we successfully validated WinPE and other Linux distributions.
 
> 
> > The first patch in this series update the generic tables which are
> > common for all platfoms. The subsequent patches in this series update
> > platform specific ACPI tables to v6.4 for the respective platform.
> >
> > This patch series also update the headers in the .aslc files to match
> > the coding style as per edk2 coding guidelines.
> >
> > This patch series should be applied on top of the patch series
> > https://edk2.groups.io/g/devel/message/88996
> >
> > Link to github branch with the patches in this series -
> > https://github.com/Pranav-Madhu/edk2-platforms/tree/topics/acpi64_for_
> > rd_platforms
> >
> >
> > Pranav Madhu (9):
> >   Platform/Sgi: Update ACPI version to v6.4
> >   Platform/Sgi: Update ACPI version to v6.4 for SGI-575 platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-N1-Edge platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-N1-Edge-X2 platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-E1-Edge platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-V1 platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-V1-MC platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-N2 platform
> >   Platform/Sgi: Update ACPI version to v6.4 for Rd-N2-Cfg1 platform
> >
> >  Platform/ARM/SgiPkg/Include/SgiAcpiHeader.h   | 219 ++++++++--------
> >  Platform/ARM/SgiPkg/AcpiTables/Dbg2.aslc      |  30 ++-
> >  Platform/ARM/SgiPkg/AcpiTables/Fadt.aslc      |  38 +--
> >  Platform/ARM/SgiPkg/AcpiTables/Gtdt.aslc      |  69 ++---
> >  Platform/ARM/SgiPkg/AcpiTables/Mcfg.aslc      |  26 +-
> >  .../ARM/SgiPkg/AcpiTables/RdE1Edge/Madt.aslc  | 247
> > +++++++++---------  .../ARM/SgiPkg/AcpiTables/RdE1Edge/Pptt.aslc  |
> > 106 ++++----  .../ARM/SgiPkg/AcpiTables/RdN1Edge/Madt.aslc  | 105
> > ++++----  .../ARM/SgiPkg/AcpiTables/RdN1Edge/Pptt.aslc  |  88 ++++---
> >  .../SgiPkg/AcpiTables/RdN1EdgeX2/Hmat.aslc    |  52 ++--
> >  .../SgiPkg/AcpiTables/RdN1EdgeX2/Madt.aslc    | 151 ++++++-----
> >  .../SgiPkg/AcpiTables/RdN1EdgeX2/Pptt.aslc    |  92 +++----
> >  .../SgiPkg/AcpiTables/RdN1EdgeX2/Srat.aslc    |  74 +++---
> >  Platform/ARM/SgiPkg/AcpiTables/RdN2/Madt.aslc | 163 ++++++------
> > Platform/ARM/SgiPkg/AcpiTables/RdN2/Pptt.aslc |  77 +++---
> > .../ARM/SgiPkg/AcpiTables/RdN2Cfg1/Madt.aslc  | 112 ++++----
> > .../ARM/SgiPkg/AcpiTables/RdN2Cfg1/Pptt.aslc  |  73 +++---
> > Platform/ARM/SgiPkg/AcpiTables/RdV1/Madt.aslc | 159 +++++------
> > Platform/ARM/SgiPkg/AcpiTables/RdV1/Pptt.aslc |  77 +++---
> >  .../ARM/SgiPkg/AcpiTables/RdV1Mc/Hmat.aslc    |  64 +++--
> >  .../ARM/SgiPkg/AcpiTables/RdV1Mc/Madt.aslc    | 165 ++++++------
> >  .../ARM/SgiPkg/AcpiTables/RdV1Mc/Pptt.aslc    |  81 +++---
> >  .../ARM/SgiPkg/AcpiTables/RdV1Mc/Srat.aslc    |  82 +++---
> >  .../ARM/SgiPkg/AcpiTables/Sgi575/Madt.aslc    | 105 ++++----
> >  .../ARM/SgiPkg/AcpiTables/Sgi575/Pptt.aslc    |  86 +++---
> >  Platform/ARM/SgiPkg/AcpiTables/Spcr.aslc      |  29 +-
> >  26 files changed, 1343 insertions(+), 1227 deletions(-)
> >
> > --
> > 2.17.1
> >

Regards,
Pranav