Re: [PATCH] ArmPkg: Update Redistributor granularity for GICv4

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

Hi Evan, Sami,

On Fri, Nov 04, 2016 at 05:52:52PM +0100, evan.lloyd@arm.com wrote:
> From: Sami Mujawar <sami.mujawar@arm.com>
> 
> Updated Redistributor base calculation to allow for the fact that
> GICv4 has 2 additional 64KB frames (for VLPI and a reserved frame).
> The code now tests the VLPIS bit in the GICR_TYPER register
> and calculates the Redistributor granularity accordingly.

Am I understanding it correctly, that this patch is required to
provide GICv4 support?

> The code changes are:
>   GICR_TYPER register fields, etc, added to the header.
>   Loop updated to pay attention to GICR_TYPER.Last.
>   Derive frame "stride" size from GICR_TYPER.VLPIS.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
> Signed-off-by: Evan Lloyd <evan.lloydr@arm.com>
> ---
> Code is available at:
> https://github.com/EvanLloyd/tianocore/tree/639_gicv4_v1
> 
>  ArmPkg/Include/Library/ArmGicLib.h | 17 ++++++++-
>  ArmPkg/Drivers/ArmGic/ArmGicLib.c  | 40 +++++++++++++-------
>  2 files changed, 41 insertions(+), 16 deletions(-)
> 
> diff --git a/ArmPkg/Include/Library/ArmGicLib.h b/ArmPkg/Include/Library/ArmGicLib.h
> index 4364f3ffef464596f64cf59881d703cf54cf0ddd..079489fe76ab481915ce9da3702d351fd3cb5f0e 100644
> --- a/ArmPkg/Include/Library/ArmGicLib.h
> +++ b/ArmPkg/Include/Library/ArmGicLib.h
> @@ -55,12 +55,25 @@
>  // GIC Redistributor
>  //
>  
> -#define ARM_GICR_CTLR_FRAME_SIZE    SIZE_64KB
> -#define ARM_GICR_SGI_PPI_FRAME_SIZE SIZE_64KB
> +#define ARM_GICR_CTLR_FRAME_SIZE         SIZE_64KB
> +#define ARM_GICR_SGI_PPI_FRAME_SIZE      SIZE_64KB
> +#define ARM_GICR_SGI_VLPI_FRAME_SIZE     SIZE_64KB
> +#define ARM_GICR_SGI_RESERVED_FRAME_SIZE SIZE_64KB
>  
>  // GIC Redistributor Control frame
>  #define ARM_GICR_TYPER          0x0008  // Redistributor Type Register
>  
> +// GIC Redistributor TYPER bit assignments
> +#define ARM_GICR_TYPER_PLPIS        (1 << 0)    // Physical LPIs
> +#define ARM_GICR_TYPER_VLPIS        (1 << 1)    // Virtual LPIs
> +#define ARM_GICR_TYPER_DIRECTLPI    (1 << 3)    // Direct LPIs
> +#define ARM_GICR_TYPER_LAST         (1 << 4)    // Last Redistributor in series
> +#define ARM_GICR_TYPER_DPGS         (1 << 5)    // Disable Processor Group
> +                                                // Selection Support
> +#define ARM_GICR_TYPER_PROCNO       (0xFFFF << 8)      // Processor Number
> +#define ARM_GICR_TYPER_COMMONLPIAFF (0x3 << 24)        // Common LPI Affinity
> +#define ARM_GICR_TYPER_AFFINITY     (0xFFFFFFFF << 32) // Redistributor Affinity
> +
>  // GIC SGI & PPI Redistributor frame
>  #define ARM_GICR_ISENABLER      0x0100  // Interrupt Set-Enable Registers
>  #define ARM_GICR_ICENABLER      0x0180  // Interrupt Clear-Enable Registers
> diff --git a/ArmPkg/Drivers/ArmGic/ArmGicLib.c b/ArmPkg/Drivers/ArmGic/ArmGicLib.c
> index e658e9bff5d8107b3914bdf1e9e1e51a4e4d4cd7..b51d2b3ec55d277e36835669956b4dd866cfc5c6 100644
> --- a/ArmPkg/Drivers/ArmGic/ArmGicLib.c
> +++ b/ArmPkg/Drivers/ArmGic/ArmGicLib.c
> @@ -1,6 +1,6 @@
>  /** @file
>  *
> -*  Copyright (c) 2011-2015, ARM Limited. All rights reserved.
> +*  Copyright (c) 2011-2016, ARM Limited. All rights reserved.
>  *
>  *  This program and the accompanying materials
>  *  are licensed and made available under the terms and conditions of the BSD License
> @@ -19,6 +19,16 @@
>  #include <Library/IoLib.h>
>  #include <Library/PcdLib.h>
>  
> +// In GICv3, there are 2 x 64KB frames:
> +// Redistributor control frame + SGI Control & Generation frame
> +#define GIC_V3_REDISTRIBUTOR_GRANULARITY  (ARM_GICR_CTLR_FRAME_SIZE \
> +                                           + ARM_GICR_SGI_PPI_FRAME_SIZE)
> +// In GICv4, there are an additional 2 x 64KB frames:
> +// VLPI frame + Reserved page frame
> +#define GIC_V4_REDISTRIBUTOR_GRANULARITY  (GIC_V3_REDISTRIBUTOR_GRANULARITY \
> +                                           + ARM_GICR_SGI_VLPI_FRAME_SIZE \
> +                                           + ARM_GICR_SGI_RESERVED_FRAME_SIZE)
> +
>  /**
>   *
>   * Return whether the Source interrupt index refers to a shared interrupt (SPI)
> @@ -40,6 +50,7 @@ SourceIsSpi (
>   *
>   * @retval Base address of the associated GIC Redistributor
>   */
> +

This added blank line between description and function does not appear
to follow comon style (including earlier in this file).

>  STATIC
>  UINTN
>  GicGetCpuRedistributorBase (
> @@ -47,37 +58,38 @@ GicGetCpuRedistributorBase (
>    IN ARM_GIC_ARCH_REVISION Revision
>    )
>  {
> -  UINTN Index;
>    UINTN MpId;
> -  UINTN CpuAffinity;
> -  UINTN Affinity;
> -  UINTN GicRedistributorGranularity;
> +  UINT32 CpuAffinity;
> +  UINT32 Affinity;

This is just sufficiently related to the change that I'll let it slide
with a grumble.

*grumble*

>    UINTN GicCpuRedistributorBase;
> +  UINT64 GicRTyper;
>  
>    MpId = ArmReadMpidr ();
>    // Define CPU affinity as Affinity0[0:8], Affinity1[9:15], Affinity2[16:23], Affinity3[24:32]
>    // whereas Affinity3 is defined at [32:39] in MPIDR
>    CpuAffinity = (MpId & (ARM_CORE_AFF0 | ARM_CORE_AFF1 | ARM_CORE_AFF2)) | ((MpId & ARM_CORE_AFF3) >> 8);
>  
> -  if (Revision == ARM_GIC_ARCH_REVISION_3) {
> -    // 2 x 64KB frame: Redistributor control frame + SGI Control & Generation frame
> -    GicRedistributorGranularity = ARM_GICR_CTLR_FRAME_SIZE + ARM_GICR_SGI_PPI_FRAME_SIZE;
> -  } else {
> +  if (Revision < ARM_GIC_ARCH_REVISION_3) {
>      ASSERT_EFI_ERROR (EFI_UNSUPPORTED);
>      return 0;
>    }
>  
>    GicCpuRedistributorBase = GicRedistributorBase;
>  
> -  for (Index = 0; Index < PcdGet32 (PcdCoreCount); Index++) {
> -    Affinity = MmioRead64 (GicCpuRedistributorBase + ARM_GICR_TYPER) >> 32;
> +  do {
> +    GicRTyper = MmioRead64 (GicCpuRedistributorBase + ARM_GICR_TYPER);
> +    Affinity = GicRTyper >> 32;
>      if (Affinity == CpuAffinity) {
>        return GicCpuRedistributorBase;
>      }
>  
> -    // Move to the next GIC Redistributor frame
> -    GicCpuRedistributorBase += GicRedistributorGranularity;
> -  }
> +    // Move to the next GIC Redistributor frame.
> +    // The GIC specification does not forbid a mixture of v3 and v4 frames,
> +    // so we test VLPIS for each frame.
> +    GicCpuRedistributorBase += ((ARM_GICR_TYPER_VLPIS & GicRTyper)
> +                                ? GIC_V4_REDISTRIBUTOR_GRANULARITY
> +                                : GIC_V3_REDISTRIBUTOR_GRANULARITY);
> +  } while (0 == (GicRTyper & ARM_GICR_TYPER_LAST));

Rather than the jeopardy comparison, can that just be
  } while (!(GicRTyper & ARM_GICR_TYPR_LAST))
?

>  
>    // The Redistributor has not been found for the current CPU
>    ASSERT_EFI_ERROR (EFI_NOT_FOUND);
> -- 
> Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")
>