Re: [PATCH v2 1/4] ArmPkg/ArmDmaLib: use DMA buffer alignment from CPU arch protocol

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

On Sat, Nov 12, 2016 at 02:02:25PM +0100, Ard Biesheuvel wrote:
> Instead of depending on ArmLib to retrieve the CWG directly, use
> the DMA buffer alignment exposed by the CPU arch protocol. This
> removes our dependency on ArmLib, which makes the library a bit
> more architecture independent.
> 
> While we're in there, rename gCpu to mCpu to better reflect its
> local scope, and reflow some lines that we're modifying anyway.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

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

> ---
>  ArmPkg/Library/ArmDmaLib/ArmDmaLib.c   | 18 ++++++++----------
>  ArmPkg/Library/ArmDmaLib/ArmDmaLib.inf |  2 --
>  2 files changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
> index d48d6ff6dbbb..03fd9f3278e6 100644
> --- a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
> +++ b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
> @@ -22,7 +22,6 @@
>  #include <Library/UncachedMemoryAllocationLib.h>
>  #include <Library/IoLib.h>
>  #include <Library/BaseMemoryLib.h>
> -#include <Library/ArmLib.h>
>  
>  #include <Protocol/Cpu.h>
>  
> @@ -36,8 +35,7 @@ typedef struct {
>  
>  
>  
> -EFI_CPU_ARCH_PROTOCOL      *gCpu;
> -UINTN                      gCacheAlignment = 0;
> +STATIC EFI_CPU_ARCH_PROTOCOL      *mCpu;
>  
>  /**
>    Provides the DMA controller-specific addresses needed to access system memory.
> @@ -92,8 +90,8 @@ DmaMap (
>  
>    *Mapping = Map;
>  
> -  if ((((UINTN)HostAddress & (gCacheAlignment - 1)) != 0) ||
> -      ((*NumberOfBytes & (gCacheAlignment - 1)) != 0)) {
> +  if ((((UINTN)HostAddress & (mCpu->DmaBufferAlignment - 1)) != 0) ||
> +      ((*NumberOfBytes & (mCpu->DmaBufferAlignment - 1)) != 0)) {
>  
>      // Get the cacheability of the region
>      Status = gDS->GetMemorySpaceDescriptor (*DeviceAddress, &GcdDescriptor);
> @@ -154,7 +152,8 @@ DmaMap (
>      DEBUG_CODE_END ();
>  
>      // Flush the Data Cache (should not have any effect if the memory region is uncached)
> -    gCpu->FlushDataCache (gCpu, *DeviceAddress, *NumberOfBytes, EfiCpuFlushTypeWriteBackInvalidate);
> +    mCpu->FlushDataCache (mCpu, *DeviceAddress, *NumberOfBytes,
> +            EfiCpuFlushTypeWriteBackInvalidate);
>    }
>  
>    Map->HostAddress   = (UINTN)HostAddress;
> @@ -211,7 +210,8 @@ DmaUnmap (
>        //
>        // Make sure we read buffer from uncached memory and not the cache
>        //
> -      gCpu->FlushDataCache (gCpu, Map->HostAddress, Map->NumberOfBytes, EfiCpuFlushTypeInvalidate);
> +      mCpu->FlushDataCache (mCpu, Map->HostAddress, Map->NumberOfBytes,
> +              EfiCpuFlushTypeInvalidate);
>      }
>    }
>  
> @@ -311,11 +311,9 @@ ArmDmaLibConstructor (
>    EFI_STATUS              Status;
>  
>    // Get the Cpu protocol for later use
> -  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&gCpu);
> +  Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&mCpu);
>    ASSERT_EFI_ERROR(Status);
>  
> -  gCacheAlignment = ArmCacheWritebackGranule ();
> -
>    return Status;
>  }
>  
> diff --git a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.inf b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.inf
> index 95c13006eaac..31de3cfd828c 100644
> --- a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.inf
> +++ b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.inf
> @@ -37,8 +37,6 @@ [LibraryClasses]
>    UncachedMemoryAllocationLib
>    IoLib
>    BaseMemoryLib
> -  ArmLib
> -
>  
>  [Protocols]
>    gEfiCpuArchProtocolGuid
> -- 
> 2.7.4
>