Re: [PATCH] ArmPkg/ArmSmcPsciResetSystemLib: add support for warm reboot

[Leif Lindholm <leif.lindholm@linaro.org>]

On Fri, Oct 06, 2017 at 09:41:52PM +0100, Ard Biesheuvel wrote:
> PSCI SYSTEM_RESET is specified as a cold reboot, which does not
> preserve the contents of DRAM. In version 1.1, a new reset method
> was introduced that allows a warm reboot to be requested.
> 
> This is especially relevant for capsule update, given that it will
> invoke a warm reboot before processing the capsule, under the
> assumption that the capsule will still be in memory when the PEI
> phase is reentered.
> 
> So wire up the [rather inaccurately named] EnterS3WithImmediateWake()
> entry point that the capsule update runtime uses to the new PSCI 1.1
> warm reboot. Note that many PSCI implementations will not support this
> yet, so fall back to a cold reboot if warm reboot fails.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Well, I meant to refactor the SMC call macros as an improved
foundation for this, but that is clearly not happening before I leave
on sabbatical.

So:
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

And I'll look into refactoring this if and when I look into that once
I get back.

> ---
> 
> I don't actually need this code for Synquacer, but given that I had
> already wrote it, we may just as well merge it.
> 
>  ArmPkg/Include/IndustryStandard/ArmStdSmc.h                        | 10 +++++++---
>  ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c | 14 ++++++++++++--
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
> index 593a3ce729ce..41b086947eaa 100644
> --- a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
> +++ b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
> @@ -57,10 +57,12 @@
>  #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
> +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH32  0x84000012
>  
> -/* The current PSCI version is:  0.2 */
> -#define ARM_SMC_PSCI_VERSION_MAJOR  0
> -#define ARM_SMC_PSCI_VERSION_MINOR  2
> +/* The current PSCI version is:  1.1 */
> +#define ARM_SMC_PSCI_VERSION_MAJOR  1
> +#define ARM_SMC_PSCI_VERSION_MINOR  1
>  #define ARM_SMC_PSCI_VERSION  \
>    ((ARM_SMC_PSCI_VERSION_MAJOR << 16) | ARM_SMC_PSCI_VERSION_MINOR)
>  
> @@ -93,4 +95,6 @@
>  #define ARM_SMC_ID_PSCI_AFFINITY_INFO_OFF         1
>  #define ARM_SMC_ID_PSCI_AFFINITY_INFO_ON_PENDING  2
>  
> +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_WARM  0
> +
>  #endif
> diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> index d6d26bce5009..ffd726554c0f 100644
> --- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> +++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> @@ -55,7 +55,17 @@ ResetWarm (
>    VOID
>    )
>  {
> -  // Map a warm reset into a cold reset
> +  ARM_SMC_ARGS ArmSmcArgs;
> +
> +#if defined(MDE_CPU_AARCH64)
> +  ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64;
> +#else
> +  ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH32;
> +#endif
> +  ArmSmcArgs.Arg1 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_WARM;
> +  ArmCallSmc (&ArmSmcArgs);
> +
> +  // Fall back to cold reset if unsupported
>    ResetCold ();
>  }
>  
> @@ -89,7 +99,7 @@ EnterS3WithImmediateWake (
>    VOID
>    )
>  {
> -  // Not implemented
> +  ResetWarm ();
>  }
>  
>  /**
> -- 
> 2.11.0
>