Re: [platforms: PATCH v2 01/10] Marvell/Drivers: MvI2cDxe: Abort transaction immediately upon fail

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

On Fri, Oct 27, 2017 at 03:13:43AM +0200, Marcin Wojtas wrote:
> From: David Greeson <dgreeson@cisco.com>
> 
> Although the I2C transaction routines were prepared to
> return their status, they were never used. This could
> cause bus lock-up e.g. in case of failing to send a
> slave address, the data transfer was attempted to be
> continued anyway.
> 
> This patch fixes faulty behavior by checking transaction
> status and stopping it immediately, once the fail
> is detected. On the occasion fix style around modified
> functions calls.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: David Greeson <dgreeson@cisco.com>
> [Style adjustment and cleanup]
> Signed-off-by: Marcin Wojtas <mw@semihalf.com>

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

> ---
>  Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c | 62 +++++++++++++-------
>  1 file changed, 41 insertions(+), 21 deletions(-)
> 
> diff --git a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
> index d85ee0b..b4599d2 100755
> --- a/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
> +++ b/Platform/Marvell/Drivers/I2c/MvI2cDxe/MvI2cDxe.c
> @@ -565,6 +565,7 @@ MvI2cStartRequest (
>    UINTN Transmitted;
>    I2C_MASTER_CONTEXT *I2cMasterContext = I2C_SC_FROM_MASTER(This);
>    EFI_I2C_OPERATION *Operation;
> +  EFI_STATUS Status = EFI_SUCCESS;
>  
>    ASSERT (RequestPacket != NULL);
>    ASSERT (I2cMasterContext != NULL);
> @@ -574,33 +575,52 @@ MvI2cStartRequest (
>      ReadMode = Operation->Flags & I2C_FLAG_READ;
>  
>      if (Count == 0) {
> -      MvI2cStart ( I2cMasterContext,
> -                   (SlaveAddress << 1) | ReadMode,
> -                   I2C_TRANSFER_TIMEOUT
> -                 );
> +      Status = MvI2cStart (I2cMasterContext,
> +                 (SlaveAddress << 1) | ReadMode,
> +                 I2C_TRANSFER_TIMEOUT);
>      } else if (!(Operation->Flags & I2C_FLAG_NORESTART)) {
> -      MvI2cRepeatedStart ( I2cMasterContext,
> -                           (SlaveAddress << 1) | ReadMode,
> -                           I2C_TRANSFER_TIMEOUT
> -                         );
> +      Status = MvI2cRepeatedStart (I2cMasterContext,
> +                 (SlaveAddress << 1) | ReadMode,
> +                 I2C_TRANSFER_TIMEOUT);
>      }
>  
> +    /* I2C transaction was aborted, so stop further transactions */
> +    if (EFI_ERROR (Status)) {
> +      MvI2cStop (I2cMasterContext);
> +      break;
> +    }
> +
> +    /*
> +     * If sending the slave address was successful,
> +     * proceed to read or write section.
> +     */
>      if (ReadMode) {
> -      MvI2cRead ( I2cMasterContext,
> -                  Operation->Buffer,
> -                  Operation->LengthInBytes,
> -                  &Transmitted,
> -                  Count == 1,
> -                  I2C_TRANSFER_TIMEOUT
> -                 );
> +      Status = MvI2cRead (I2cMasterContext,
> +                 Operation->Buffer,
> +                 Operation->LengthInBytes,
> +                 &Transmitted,
> +                 Count == 1,
> +                 I2C_TRANSFER_TIMEOUT);
> +      Operation->LengthInBytes = Transmitted;
>      } else {
> -      MvI2cWrite ( I2cMasterContext,
> -                   Operation->Buffer,
> -                   Operation->LengthInBytes,
> -                   &Transmitted,
> -                   I2C_TRANSFER_TIMEOUT
> -                  );
> +      Status = MvI2cWrite (I2cMasterContext,
> +                 Operation->Buffer,
> +                 Operation->LengthInBytes,
> +                 &Transmitted,
> +                 I2C_TRANSFER_TIMEOUT);
> +      Operation->LengthInBytes = Transmitted;
>      }
> +
> +    /*
> +     * The I2C read or write transaction failed.
> +     * Stop the I2C transaction.
> +     */
> +    if (EFI_ERROR (Status)) {
> +      MvI2cStop (I2cMasterContext);
> +      break;
> +    }
> +
> +    /* Check if there is any more data to be sent */
>      if (Count == RequestPacket->OperationCount - 1) {
>        MvI2cStop ( I2cMasterContext );
>      }
> -- 
> 2.7.4
>