Re: [PATCH] SourceLevelDebugPkg DebugCommUsb3: Return error when debug cap is reset

["Wu, Hao A" <hao.a.wu@intel.com>]

Reviewed-by: Hao Wu <hao.a.wu@intel.com>

Best Regards,
Hao Wu


> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Star
> Zeng
> Sent: Monday, March 19, 2018 8:46 PM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu; Wu, Hao A; Zeng, Star
> Subject: [edk2] [PATCH] SourceLevelDebugPkg DebugCommUsb3: Return error
> when debug cap is reset
> 
> When source level debug is enabled, but debug cable is not connected,
> XhcResetHC() in XhciReg.c will reset the host controller, the debug
> capability registers will be also reset. After the code in
> InitializeUsbDebugHardware() sets DCE bit and LSE bit to "1" in DCCTRL,
> there will be DMA on 0 (the value of some debug capability registers
> for data transfer is 0) address buffer, fault info like below will
> appear when IOMMU based on VTd is enabled.
> 
>   VER_REG     - 0x00000010
>   CAP_REG     - 0x00D2008C40660462
>   ECAP_REG    - 0x0000000000F050DA
>   GSTS_REG    - 0xC0000000
>   RTADDR_REG  - 0x0000000086512000
>   CCMD_REG    - 0x2800000000000000
>   FSTS_REG    - 0x00000002
>   FECTL_REG   - 0xC0000000
>   FEDATA_REG  - 0x00000000
>   FEADDR_REG  - 0x00000000
>   FEUADDR_REG - 0x00000000
>   FRCD_REG[0] - 0xC0000006000000A0 0000000000000000
>     Fault Info - 0x0000000000000000
>     Source - B00 D14 F00
>     Type - 1 (read)
>     Reason - 6
>   IVA_REG     - 0x0000000000000000
>   IOTLB_REG   - 0x1200000000000000
> 
> This patch is to return error for the case.
> 
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Hao Wu <hao.a.wu@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>  .../DebugCommunicationLibUsb3/DebugCommunicationLibUsb3Common.c   |
> 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git
> a/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommun
> icationLibUsb3Common.c
> b/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommun
> icationLibUsb3Common.c
> index fb9ca84fc7bc..86ecc2f9dbc7 100644
> ---
> a/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommun
> icationLibUsb3Common.c
> +++
> b/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommun
> icationLibUsb3Common.c
> @@ -673,11 +673,19 @@ InitializeUsbDebugHardware (
>    UINTN                           Index;
>    UINT8                           TotalUsb3Port;
>    EFI_PHYSICAL_ADDRESS            XhciOpRegister;
> +  UINT32                          Dcddi1;
> 
>    XhciOpRegister = Handle->XhciOpRegister;
>    TotalUsb3Port = MmioRead32 (((UINTN) Handle->XhciMmioBase +
> XHC_HCSPARAMS1_OFFSET)) >> 24;
> 
>    if (Handle->Initialized == USB3DBG_NOT_ENABLED) {
> +    Dcddi1 = XhcReadDebugReg (Handle,XHC_DC_DCDDI1);
> +    if (Dcddi1 != (UINT32)((XHCI_DEBUG_DEVICE_VENDOR_ID << 16) |
> XHCI_DEBUG_DEVICE_PROTOCOL)) {
> +      //
> +      // The debug capability has been reset by other code, return device error.
> +      //
> +      return EFI_DEVICE_ERROR;
> +    }
>      //
>      // If XHCI supports debug capability, hardware resource has been allocated,
>      // but it has not been enabled, try to enable again.
> --
> 2.7.0.windows.1
> 
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