Re: [edk2][PATCH V4 1/1] ArmPkg: Handle warm reboot request correctly

["Ard Biesheuvel" <ardb@kernel.org>]

On Wed, 24 Aug 2022 at 18:44, Pranav Madhu <pranav.madhu@arm.com> wrote:
>
> The warm reboot requests from OSPM are mapped to cold reboot. To handle
> the warm reboot separately from a cold reboot, update
> ArmSmcPsciResetSystemLib and to invoke the PSCI call with parameters
> for warm reboot.
>
> Signed-off-by: Pranav Madhu <pranav.madhu@arm.com>

Merged as #3287

> ---
>  ArmPkg/Include/IndustryStandard/ArmStdSmc.h                        |  2 ++
>  ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c | 19 +++++++++++++++++--
>  2 files changed, 19 insertions(+), 2 deletions(-)
>
> Changes since V1:
> - Addressed comments from Ard.
>
> Changes since V2:
> - Remove 32 bit warm reboot PSCI support.
> - Update ResetWarm() to check whether platform support warm reset.
> - Addressed comments from Sami
>
> Changes since V3:
> - Rebased on top of latest upstream master branch.
>
> 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..78ce77cd734d 100644
> --- a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
> +++ b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
> @@ -93,6 +93,8 @@
>  #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_FEATURES               0x8400000A
> +#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/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> index af6738459e43..b710cd066e8b 100644
> --- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> +++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> @@ -3,6 +3,7 @@
>
>    Copyright (c) 2017 - 2018, Linaro Ltd. All rights reserved.<BR>
>    Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2022, Arm Limited. All rights reserved.<BR>
>
>    SPDX-License-Identifier: BSD-2-Clause-Patent
>
> @@ -47,8 +48,22 @@ ResetWarm (
>    VOID
>    )
>  {
> -  // Map a warm reset into a cold reset
> -  ResetCold ();
> +  UINTN Arg1 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64;
> +  UINTN ret;
> +
> +  // Is SYSTEM_RESET2 supported?
> +  ret = ArmCallSmc0 (ARM_SMC_ID_PSCI_FEATURES, &Arg1, NULL, NULL);
> +  if (ret == ARM_SMC_PSCI_RET_SUCCESS) {
> +    // Send PSCI SYSTEM_RESET2 command
> +    ArmCallSmc0 (Arg1, NULL, NULL, NULL);
> +  } else {
> +    // Map a warm reset into a cold reset
> +    DEBUG ((
> +      DEBUG_INFO,
> +      "Warm reboot not supported by platform, issuing cold reboot\n"
> +      ));
> +    ResetCold ();
> +  }
>  }
>
>  /**
> --
> 2.25.1
>