Re: [PATCH] EmbeddedPkg/MmcDxe: Align the ExtCSD buffer

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

On Thu, Jun 29, 2017 at 05:03:50PM +0800, Jun Nie wrote:
> ExtCSD structure may be read via DMA. So align it to
> page to avoid data corruption.

So, this is possibly a valid thing to do, but this is not what you
said in the last version. The last version said you needed 64-bit
alignment, and this is already guaranteed by all of the allocation
functions.

> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Jun Nie <jun.nie@linaro.org>
> ---
>  EmbeddedPkg/Universal/MmcDxe/Mmc.h               |  2 +-
>  EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c | 11 ++++++++---
>  2 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/EmbeddedPkg/Universal/MmcDxe/Mmc.h b/EmbeddedPkg/Universal/MmcDxe/Mmc.h
> index 8a7d5a3..f3e56ff 100644
> --- a/EmbeddedPkg/Universal/MmcDxe/Mmc.h
> +++ b/EmbeddedPkg/Universal/MmcDxe/Mmc.h
> @@ -319,7 +319,7 @@ typedef struct  {
>    OCR       OCRData;
>    CID       CIDData;
>    CSD       CSDData;
> -  ECSD      ECSDData;                         // MMC V4 extended card specific
> +  ECSD      *ECSDData;                         // MMC V4 extended card specific
>  } CARD_INFO;
>  
>  typedef struct _MMC_HOST_INSTANCE {
> diff --git a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> index c28207e..6bb65c3 100644
> --- a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> +++ b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> @@ -13,6 +13,7 @@
>  **/
>  
>  #include <Library/BaseMemoryLib.h>
> +#include <Library/MemoryAllocationLib.h>
>  #include <Library/TimerLib.h>
>  
>  #include "Mmc.h"
> @@ -210,12 +211,16 @@ EmmcIdentificationMode (
>    }
>  
>    // Fetch ECSD
> +  MmcHostInstance->CardInfo.ECSDData = AllocatePages (1);

No magic numbers please.
Suggest EFI_SIZE_TO_PAGES (sizeof (ECSD));
Or AllocatePool (EFI_SIZE_TO_PAGES (sizeof (ECSD)));

I'm not seeing a balancing FreePages call in this patch.
My guess would be that DestroyMmcHostInstance() would be the
correct location for it.

> +  if (MmcHostInstance->CardInfo.ECSDData == NULL) {
> +    return EFI_BUFFER_TOO_SMALL;

I think EFI_OUT_OF_RESOURCES would be more appropriate.

/
    Leif

> +  }
>    Status = Host->SendCommand (Host, MMC_CMD8, 0);
>    if (EFI_ERROR (Status)) {
>      DEBUG ((EFI_D_ERROR, "EmmcIdentificationMode(): ECSD fetch error, Status=%r.\n", Status));
>    }
>  
> -  Status = Host->ReadBlockData (Host, 0, 512, (UINT32 *)&(MmcHostInstance->CardInfo.ECSDData));
> +  Status = Host->ReadBlockData (Host, 0, 512, (UINT32 *)MmcHostInstance->CardInfo.ECSDData);
>    if (EFI_ERROR (Status)) {
>      DEBUG ((EFI_D_ERROR, "EmmcIdentificationMode(): ECSD read error, Status=%r.\n", Status));
>      return Status;
> @@ -237,7 +242,7 @@ EmmcIdentificationMode (
>    Media->LogicalBlocksPerPhysicalBlock = 1;
>    Media->IoAlign = 4;
>    // Compute last block using bits [215:212] of the ECSD
> -  Media->LastBlock = MmcHostInstance->CardInfo.ECSDData.SECTOR_COUNT - 1; // eMMC isn't supposed to report this for
> +  Media->LastBlock = MmcHostInstance->CardInfo.ECSDData->SECTOR_COUNT - 1; // eMMC isn't supposed to report this for
>    // Cards <2GB in size, but the model does.
>  
>    // Setup card type
> @@ -258,7 +263,7 @@ InitializeEmmcDevice (
>    UINT32     TimingMode[4] = {EMMCHS52DDR1V2, EMMCHS52DDR1V8, EMMCHS52, EMMCHS26};
>  
>    Host  = MmcHostInstance->MmcHost;
> -  ECSDData = &MmcHostInstance->CardInfo.ECSDData;
> +  ECSDData = MmcHostInstance->CardInfo.ECSDData;
>    if (ECSDData->DEVICE_TYPE == EMMCBACKWARD)
>      return EFI_SUCCESS;
>  
> -- 
> 1.9.1
>