Re: [edk2-devel][PATCH 2/5] Platform/RPi: Separate RAM descriptors between 0-3 GB and 3+ GB

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

On Tue, 3 Mar 2020 at 11:33, Pete Batard <pete@akeo.ie> wrote:
>
> From: Andrei Warkentin <andrey.warkentin@gmail.com>
>
> This is required so that we can make the 3 to 4 GB segment of
> the Raspberry Pi 4 a user-configurable option.
>
> This also removes the need for the PcdAcpiBasicMode PCD.
>
> Signed-off-by: Pete Batard <pete@akeo.ie>

Please fix the commit log so it is clear what 'this' means

> ---
>  Platform/RaspberryPi/Library/PlatformLib/PlatformLib.inf  |  3 --
>  Platform/RaspberryPi/Library/PlatformLib/RaspberryPiMem.c | 33 ++++++++++++++------
>  2 files changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/Platform/RaspberryPi/Library/PlatformLib/PlatformLib.inf b/Platform/RaspberryPi/Library/PlatformLib/PlatformLib.inf
> index 9abcc2cc0075..77cdbe399a06 100644
> --- a/Platform/RaspberryPi/Library/PlatformLib/PlatformLib.inf
> +++ b/Platform/RaspberryPi/Library/PlatformLib/PlatformLib.inf
> @@ -59,8 +59,5 @@ [FixedPcd]
>    gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize
>    gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize
>
> -[FeaturePcd]
> -  gRaspberryPiTokenSpaceGuid.PcdAcpiBasicMode
> -
>  [Ppis]
>    gArmMpCoreInfoPpiGuid
> diff --git a/Platform/RaspberryPi/Library/PlatformLib/RaspberryPiMem.c b/Platform/RaspberryPi/Library/PlatformLib/RaspberryPiMem.c
> index 4b388465cdde..3f257d4fa528 100644
> --- a/Platform/RaspberryPi/Library/PlatformLib/RaspberryPiMem.c
> +++ b/Platform/RaspberryPi/Library/PlatformLib/RaspberryPiMem.c
> @@ -25,7 +25,7 @@ UINT32 mBoardRevision;
>
>
>  // The total number of descriptors, including the final "end-of-table" descriptor.
> -#define MAX_VIRTUAL_MEMORY_MAP_DESCRIPTORS 10
> +#define MAX_VIRTUAL_MEMORY_MAP_DESCRIPTORS 11
>
>  STATIC BOOLEAN                  VirtualMemoryInfoInitialized = FALSE;
>  STATIC RPI_MEMORY_REGION_INFO   VirtualMemoryInfo[MAX_VIRTUAL_MEMORY_MAP_DESCRIPTORS];
> @@ -60,6 +60,7 @@ ArmPlatformGetVirtualMemoryMap (
>  {
>    UINTN                         Index = 0;
>    UINTN                         GpuIndex;
> +  INT64                         OrigMemorySize;
>    INT64                         SystemMemorySize;
>    ARM_MEMORY_REGION_DESCRIPTOR  *VirtualMemoryTable;
>
> @@ -78,7 +79,6 @@ ArmPlatformGetVirtualMemoryMap (
>      return;
>    }
>
> -
>    // Firmware Volume
>    VirtualMemoryTable[Index].PhysicalBase    = FixedPcdGet64 (PcdFdBaseAddress);
>    VirtualMemoryTable[Index].VirtualBase     = VirtualMemoryTable[Index].PhysicalBase;

Drop this hunk please

> @@ -155,13 +155,13 @@ ArmPlatformGetVirtualMemoryMap (
>    VirtualMemoryInfo[Index].Type             = RPI_MEM_UNMAPPED_REGION;
>    VirtualMemoryInfo[Index++].Name           = L"SoC Reserved (283x)";
>
> -  if (FeaturePcdGet (PcdAcpiBasicMode)) {
> -    //
> -    // Limit the memory to 3 GB to work around the DMA bugs in the SoC without
> -    // having to rely on IORT or _DMA descriptions.
> -    //
> -    SystemMemorySize = MIN(SystemMemorySize, 3U * SIZE_1GB);
> -  }
> +  //
> +  // By default we limit the memory to 3 GB to work around the DMA bugs in the SoC, for
> +  // OSes that don't support _DMA range descriptors. On 4GB boards, it's runtime
> +  // setting to boot with 4GB, and the additional 1GB is added by ConfigDxe.
> +  //
> +  OrigMemorySize = SystemMemorySize;
> +  SystemMemorySize = MIN(SystemMemorySize, 3U * SIZE_1GB);
>
>    // If we have RAM above the 1 GB mark, declare it
>    if (SystemMemorySize - SIZE_1GB > 0) {
> @@ -170,7 +170,20 @@ ArmPlatformGetVirtualMemoryMap (
>      VirtualMemoryTable[Index].Length        = SystemMemorySize - SIZE_1GB;
>      VirtualMemoryTable[Index].Attributes    = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
>      VirtualMemoryInfo[Index].Type           = RPI_MEM_BASIC_REGION;
> -    VirtualMemoryInfo[Index++].Name         = L"Extended System RAM";
> +    VirtualMemoryInfo[Index++].Name         = L"Extended System RAM below 3GB";
> +  }
> +
> +  //
> +  // If we have RAM above 3 GB mark, declare it so it's mapped, but
> +  // don't add it to the memory map. This is done later by ConfigDxe if necessary.
> +  //
> +  if (OrigMemorySize > (3UL * SIZE_1GB)) {
> +    VirtualMemoryTable[Index].PhysicalBase  = 3UL * SIZE_1GB;
> +    VirtualMemoryTable[Index].VirtualBase   = VirtualMemoryTable[Index].PhysicalBase;
> +    VirtualMemoryTable[Index].Length        = OrigMemorySize - VirtualMemoryTable[Index].PhysicalBase;
> +    VirtualMemoryTable[Index].Attributes    = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
> +    VirtualMemoryInfo[Index].Type           = RPI_MEM_UNMAPPED_REGION;
> +    VirtualMemoryInfo[Index++].Name         = L"Extended System RAM above 3GB";
>    }
>
>    // End of Table
> --
> 2.21.0.windows.1
>