Re: [PATCH 1/3] MdeModulePkg/SdMmcPciHcDxe: Refactor command error detection

["Albecki, Mateusz" <mateusz.albecki@intel.com>]

Hi,

I will fix the 2 issues in separate patch probably before doing the refactor to avoid reverting it if the refactor introduces some unexpected issues.

Please also see inline.

Thanks,
Mateusz

> -----Original Message-----
> From: Wu, Hao A <hao.a.wu@intel.com>
> Sent: Friday, January 10, 2020 6:38 AM
> To: Albecki, Mateusz <mateusz.albecki@intel.com>; devel@edk2.groups.io
> Cc: Marcin Wojtas <mw@semihalf.com>; Gao, Zhichao
> <zhichao.gao@intel.com>; Gao, Liming <liming.gao@intel.com>
> Subject: RE: [PATCH 1/3] MdeModulePkg/SdMmcPciHcDxe: Refactor
> command error detection
> 
> Hello Mateusz,
> 
> Some inline comments below:
> 
> 
> > -----Original Message-----
> > From: Albecki, Mateusz
> > Sent: Tuesday, January 07, 2020 7:06 PM
> > To: devel@edk2.groups.io
> > Cc: Albecki, Mateusz; Wu, Hao A; Marcin Wojtas; Gao, Zhichao; Gao,
> > Liming
> > Subject: [PATCH 1/3] MdeModulePkg/SdMmcPciHcDxe: Refactor
> command
> > error detection
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1140
> >
> > Error detection function will now check if the command failure has
> > been caused by one of the errors that can appear randomly on link(CRC
> > error + end bit error). If such an error has been a cause of failure
> > function will return EFI_CRC_ERROR instead of EFI_DEVICE_ERROR to
> > indicate to the higher level that command has a chance of succeeding
> > if resent. In addition this patch also fixes 2 small bugs. First one
> > is DAT lane being reset on current limit error. Second one is data
> > timeout error not being cleared after transfer has been completed.
> 
> 
> For the 2 small issues, I would suggest to split them into separate patches,
> which would make this patch into 3 patches. You can either do the
> refactoring or fixing the 2 bugs first.
> 
> 
> >
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Marcin Wojtas <mw@semihalf.com>
> > Cc: Zhichao Gao <zhichao.gao@intel.com>
> > Cc: Liming Gao <liming.gao@intel.com>
> >
> > Signed-off-by: Mateusz Albecki <mateusz.albecki@intel.com>
> > ---
> >  MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHci.c | 234
> > +++++++++++++++--------
> >  1 file changed, 158 insertions(+), 76 deletions(-)
> >
> > diff --git a/MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHci.c
> > b/MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHci.c
> > index e7f2fac69b..8b5e54f321 100644
> > --- a/MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHci.c
> > +++ b/MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHci.c
> > @@ -7,7 +7,7 @@
> >    It would expose EFI_SD_MMC_PASS_THRU_PROTOCOL for upper layer
> use.
> >
> >    Copyright (c) 2018-2019, NVIDIA CORPORATION. All rights reserved.
> > -  Copyright (c) 2015 - 2019, Intel Corporation. All rights
> > reserved.<BR>
> > +  Copyright (c) 2015 - 2020, Intel Corporation. All rights
> > + reserved.<BR>
> >    SPDX-License-Identifier: BSD-2-Clause-Patent
> >
> >  **/
> > @@ -2137,6 +2137,154 @@ SdMmcExecTrb (
> >    return Status;
> >  }
> >
> > +/**
> > +  Performs SW reset based on passed error status mask.
> > +
> > +  @param[in]  Private       Pointer to driver private data.
> > +  @param[in]  Slot          Index of the slot to reset.
> > +  @param[in]  ErrIntStatus  Error interrupt status mask.
> > +
> > +  @retval EFI_SUCCESS  Software reset performed successfully.
> > +  @retval Other        Software reset failed.
> > +**/
> > +EFI_STATUS
> > +SdMmcSoftwareReset (
> > +  IN SD_MMC_HC_PRIVATE_DATA  *Private,
> > +  IN UINT8                   Slot,
> > +  IN UINT16                  ErrIntStatus
> > +  )
> > +{
> > +  UINT8       SwReset;
> > +  EFI_STATUS  Status;
> > +
> > +  SwReset = 0;
> > +  if ((ErrIntStatus & 0x0F) != 0) {
> > +    SwReset |= BIT1;
> > +  }
> > +  if ((ErrIntStatus & 0x70) != 0) {
> 
> 
> Thanks for this catch.
> Could you help to separate this fix to another patch?
> 
> 
> > +    SwReset |= BIT2;
> > +  }
> > +
> > +  Status  = SdMmcHcRwMmio (
> > +              Private->PciIo,
> > +              Slot,
> > +              SD_MMC_HC_SW_RST,
> > +              FALSE,
> > +              sizeof (SwReset),
> > +              &SwReset
> > +              );
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  Status = SdMmcHcWaitMmioSet (
> > +             Private->PciIo,
> > +             Slot,
> > +             SD_MMC_HC_SW_RST,
> > +             sizeof (SwReset),
> > +             0xFF,
> > +             0,
> > +             SD_MMC_HC_GENERIC_TIMEOUT
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +/**
> > +  Checks the error status in error status register
> > +  and issues appropriate software reset as described in
> > +  SD specification section 3.10.
> > +
> > +  @param[in] Private  Pointer to driver private data.
> > +  @param[in] Trb      Pointer to currently executing TRB.
> > +
> > +  @retval EFI_CRC_ERROR  CRC error happened during CMD execution.
> > +  @retval EFI_SUCCESS    No error reported.
> > +  @retval Others         Some other error happened.
> > +
> > +**/
> > +EFI_STATUS
> > +SdMmcCheckAndRecoverErrors (
> > +  IN SD_MMC_HC_PRIVATE_DATA  *Private,
> > +  IN UINT8                   Slot
> > +  )
> > +{
> > +  UINT16      IntStatus;
> > +  UINT16      ErrIntStatus;
> > +  UINT16      ErrIntStatusOr;
> > +  EFI_STATUS  Status;
> > +  EFI_STATUS  ErrorStatus;
> > +
> > +  Status = SdMmcHcRwMmio (
> > +             Private->PciIo,
> > +             Slot,
> > +             SD_MMC_HC_NOR_INT_STS,
> > +             TRUE,
> > +             sizeof (IntStatus),
> > +             &IntStatus
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  if ((IntStatus & BIT15) == 0) {
> > +    return EFI_SUCCESS;
> > +  }
> > +
> > +  Status = SdMmcHcRwMmio (
> > +             Private->PciIo,
> > +             Slot,
> > +             SD_MMC_HC_ERR_INT_STS,
> > +             TRUE,
> > +             sizeof (ErrIntStatus),
> > +             &ErrIntStatus
> > +             );
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  //
> > +  // We treat both CMD and DAT CRC errors and  // end bits errors as
> > + EFI_CRC_ERROR. This will  // let higher layer know that the error
> > + possibly  // happened due to random bus condition and the  //
> > + command can be retried.
> > +  //
> > +  if (ErrIntStatus & (BIT1 | BIT2 | BIT5 | BIT6)) {
> > +    ErrorStatus = EFI_CRC_ERROR;
> > +  } else if ((ErrIntStatus & BIT4) && (IntStatus & BIT1)){
> 
> 
> A coding style comment here, please help to explicitly compare the '&'
> operation
> result with 0 for the above checks, like:
> 
>   if ((ErrIntStatus & (BIT1 | BIT2 | BIT5 | BIT6)) != 0 ) {
> 
> 

OK

> > +    //
> > +    // If the data timeout error is reported
> > +    // but data transfer is signaled as completed we
> > +    // have to ignore data timeout.
> > +    //
> > +    ErrorStatus = EFI_SUCCESS;
> 
> 
> I am thinking it might be more clean to directly return for this case. Since
> for this case, a recovery procedure is not required, doing so can avoid
> explicitly clearing the Timeout error bit in the 'SD_MMC_HC_ERR_INT_STS'
> register.
> 
> We can still leave the clear of the bits in 'SD_MMC_HC_ERR_INT_STS' register
> to
> function SdMmcExecTrb() before the execution of next command.
> 
> 

You are right, both error and normal interrupt status are going to be reset during SdMmcExecTrb. I didn't notice it and that is why I thought it is a bug.
Reading SD host controller spec some more it seems to me like we should assume that if Transfer complete is set then no other error except for transfer timeout can be set and, as you proposed, return directly with EFI_SUCCESS. It would match previous implementation behavior.

> > +    ErrIntStatusOr = BIT4;
> > +    Status = SdMmcHcOrMmio (
> > +               Private->PciIo,
> > +               Slot,
> > +               SD_MMC_HC_ERR_INT_STS,
> > +               sizeof (ErrIntStatus),
> > +               &ErrIntStatusOr
> > +               );
> > +    if (EFI_ERROR (Status)) {
> > +      return Status;
> > +    }
> > +  } else {
> > +    ErrorStatus = EFI_DEVICE_ERROR;
> > +  }
> > +
> > +  Status = SdMmcSoftwareReset (Private, Slot, ErrIntStatus);
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  return ErrorStatus;
> > +}
> > +
> >  /**
> >    Check the TRB execution result.
> >
> > @@ -2160,10 +2308,8 @@ SdMmcCheckTrbResult (
> >    UINT32                              Response[4];
> >    UINT64                              SdmaAddr;
> >    UINT8                               Index;
> > -  UINT8                               SwReset;
> >    UINT32                              PioLength;
> >
> > -  SwReset = 0;
> >    Packet  = Trb->Packet;
> >    //
> >    // Check Trb execution result by reading Normal Interrupt Status register.
> > @@ -2179,87 +2325,23 @@ SdMmcCheckTrbResult (
> >    if (EFI_ERROR (Status)) {
> >      goto Done;
> >    }
> 
> 
> I think the below call in SdMmcCheckTrbResult():
> 
>   Status = SdMmcHcRwMmio (
>              Private->PciIo,
>              Trb->Slot,
>              SD_MMC_HC_NOR_INT_STS,
>              TRUE,
>              sizeof (IntStatus),
>              &IntStatus
>              );
> 
> can be removed. I found that the same call will be made in
> SdMmcCheckAndRecoverErrors().
> 
> Best Regards,
> Hao Wu
> 
> 

We still need to check in normal interrupt register the status of the transfer complete, DMA interrupt and buffer ready so I think the call has to stay there. That said I can pass the IntStatus to SdMmcCheckAndRecoverErrors or move the call to SdMmcHcRwMmio after the call to SdMmcCheckAndRecoverErrors. I don't really have a preference so let me know if you want me to make any changes.

> > +
> >    //
> > -  // Check Transfer Complete bit is set or not.
> > +  // Check if there are any errors reported by host controller
> > +  // and if neccessary recover the controller before next command is
> > executed.
> >    //
> > -  if ((IntStatus & BIT1) == BIT1) {
> > -    if ((IntStatus & BIT15) == BIT15) {
> > -      //
> > -      // Read Error Interrupt Status register to check if the error is
> > -      // Data Timeout Error.
> > -      // If yes, treat it as success as Transfer Complete has higher
> > -      // priority than Data Timeout Error.
> > -      //
> > -      Status = SdMmcHcRwMmio (
> > -                 Private->PciIo,
> > -                 Trb->Slot,
> > -                 SD_MMC_HC_ERR_INT_STS,
> > -                 TRUE,
> > -                 sizeof (IntStatus),
> > -                 &IntStatus
> > -                 );
> > -      if (!EFI_ERROR (Status)) {
> > -        if ((IntStatus & BIT4) == BIT4) {
> > -          Status = EFI_SUCCESS;
> > -        } else {
> > -          Status = EFI_DEVICE_ERROR;
> > -        }
> > -      }
> > -    }
> > -
> > +  Status = SdMmcCheckAndRecoverErrors (Private, Trb->Slot);
> > +  if (EFI_ERROR (Status)) {
> >      goto Done;
> >    }
> > +
> >    //
> > -  // Check if there is a error happened during cmd execution.
> > -  // If yes, then do error recovery procedure to follow SD Host Controller
> > -  // Simplified Spec 3.0 section 3.10.1.
> > +  // Check Transfer Complete bit is set or not.
> >    //
> > -  if ((IntStatus & BIT15) == BIT15) {
> > -    Status = SdMmcHcRwMmio (
> > -               Private->PciIo,
> > -               Trb->Slot,
> > -               SD_MMC_HC_ERR_INT_STS,
> > -               TRUE,
> > -               sizeof (IntStatus),
> > -               &IntStatus
> > -               );
> > -    if (EFI_ERROR (Status)) {
> > -      goto Done;
> > -    }
> > -    if ((IntStatus & 0x0F) != 0) {
> > -      SwReset |= BIT1;
> > -    }
> > -    if ((IntStatus & 0xF0) != 0) {
> > -      SwReset |= BIT2;
> > -    }
> > -
> > -    Status  = SdMmcHcRwMmio (
> > -                Private->PciIo,
> > -                Trb->Slot,
> > -                SD_MMC_HC_SW_RST,
> > -                FALSE,
> > -                sizeof (SwReset),
> > -                &SwReset
> > -                );
> > -    if (EFI_ERROR (Status)) {
> > -      goto Done;
> > -    }
> > -    Status = SdMmcHcWaitMmioSet (
> > -               Private->PciIo,
> > -               Trb->Slot,
> > -               SD_MMC_HC_SW_RST,
> > -               sizeof (SwReset),
> > -               0xFF,
> > -               0,
> > -               SD_MMC_HC_GENERIC_TIMEOUT
> > -               );
> > -    if (EFI_ERROR (Status)) {
> > -      goto Done;
> > -    }
> > -
> > -    Status = EFI_DEVICE_ERROR;
> > +  if ((IntStatus & BIT1) == BIT1) {
> >      goto Done;
> >    }
> > +
> >    //
> >    // Check if DMA interrupt is signalled for the SDMA transfer.
> >    //
> > --
> > 2.14.1.windows.1
> 

--------------------------------------------------------------------

Intel Technology Poland sp. z o.o.
ul. Slowackiego 173 | 80-298 Gdansk | Sad Rejonowy Gdansk Polnoc | VII Wydzial Gospodarczy Krajowego Rejestru Sadowego - KRS 101882 | NIP 957-07-52-316 | Kapital zakladowy 200.000 PLN.

Ta wiadomosc wraz z zalacznikami jest przeznaczona dla okreslonego adresata i moze zawierac informacje poufne. W razie przypadkowego otrzymania tej wiadomosci, prosimy o powiadomienie nadawcy oraz trwale jej usuniecie; jakiekolwiek
przegladanie lub rozpowszechnianie jest zabronione.
This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). If you are not the intended recipient, please contact the sender and delete all copies; any review or distribution by
others is strictly prohibited.