Hi Ard, Thanks for your suggestions. Please find my reply inline.
Regards, Pranav > -----Original Message----- > From: Ard Biesheuvel <a...@kernel.org> > Sent: Thursday, March 10, 2022 8:56 PM > To: Pranav Madhu <pranav.ma...@arm.com> > Cc: edk2-devel-groups-io <devel@edk2.groups.io>; Ard Biesheuvel > <ardb+tianoc...@kernel.org>; Sami Mujawar <sami.muja...@arm.com> > Subject: Re: [edk2][PATCH V1 1/1] ArmPkg: Handle warm reboot request > correctly > > On Thu, 10 Mar 2022 at 14:10, Pranav Madhu <pranav.ma...@arm.com> > wrote: > > > > The warm reboot requests are mapped to cold reboot as the power > > control module was not capable of handling the warm reboot requests in > > the legacy implementation. The support for warm reboot support is > > added into the power control module. To support warm reset, update > > ArmPsciResetSystemLib, and there by invoke the PSCI call with > > parameters for warm reboot. > > > > Signed-off-by: Pranav Madhu <pranav.ma...@arm.com> > > What happens on 32-bit platforms with this change? Will change this to PSCI_SYSTEM_RESET2_AARCH32, as this is compatible with AARCH64 as well. > > What happens if the firmware does not implement > ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64? As per PSCI 1.1 specification, what I understood is before invoking SYSTEM_RESET2, the OS should query the PSCI capabilities using PSCI_FEATURES for SYSTEM_RESET2 support. The OS should invoke RESET2 only if PSCI_FEATURES returns 0. If the OS is invoking this call without querying the features, PSCI will return UNSUPPORTED. > > > --- > > ArmPkg/Include/IndustryStandard/ArmStdSmc.h | 1 + > > ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.c | 7 > > +++++-- > > 2 files changed, 6 insertions(+), 2 deletions(-) > > > > Link to github branch for this patch - > > https://github.com/Pranav-Madhu/edk2/tree/topics/warm_reboot > > > > diff --git a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h > > b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h > > index 655edc21b205..c9059dead6e9 100644 > > --- a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h > > +++ b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h > > @@ -93,6 +93,7 @@ > > #define ARM_SMC_ID_PSCI_MIGRATE_AARCH32 0x84000005 > > #define ARM_SMC_ID_PSCI_SYSTEM_OFF 0x84000008 > > #define ARM_SMC_ID_PSCI_SYSTEM_RESET 0x84000009 > > +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64 0xc4000012 > > > > /* The current PSCI version is: 0.2 */ #define > > ARM_SMC_PSCI_VERSION_MAJOR 0 diff --git > > a/ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.c > > b/ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.c > > index 7bcd34849507..27e048ba0f7a 100644 > > --- a/ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.c > > +++ b/ArmPkg/Library/ArmPsciResetSystemLib/ArmPsciResetSystemLib.c > > @@ -45,10 +45,13 @@ LibResetSystem ( > > ARM_SMC_ARGS ArmSmcArgs; > > > > switch (ResetType) { > > + case EfiResetWarm: > > + ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64; > > + ArmSmcArgs.Arg1 = 0; > > + ArmSmcArgs.Arg2 = 0; > > + break; > > case EfiResetPlatformSpecific: > > // Map the platform specific reset as reboot > > - case EfiResetWarm: > > - // Map a warm reset into a cold reset > > case EfiResetCold: > > // Send a PSCI 0.2 SYSTEM_RESET command > > ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET; > > -- > > 2.17.1 > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#87453): https://edk2.groups.io/g/devel/message/87453 Mute This Topic: https://groups.io/mt/89685482/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
