Re: [edk2-devel] [PATCH v2] ArmPlatformPkg/PL011UartLib: Check PID2 if FiFoDepth is zero

["Samer El-Haj-Mahmoud" <samer.el-haj-mahmoud@arm.com>]

Adding Ard's new Arm e-mail address, and removing the old Linaro e-mail.

Thanks,
--Samer

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Irene
> Park via groups.io
> Sent: Monday, June 22, 2020 4:15 PM
> To: devel@edk2.groups.io; ard.biesheuvel@linaro.org
> Subject: Re: [edk2-devel] [PATCH v2] ArmPlatformPkg/PL011UartLib: Check
> PID2 if FiFoDepth is zero
>
> Hi Ard,
> Would you please review this change ?
> I also wonder what you think of the following.
>
> #if FixedPcdGet16 (PcdUartDefaultReceiveFifoDepth) == 0 VS if
> (FixedPcdGet16 (PcdUartDefaultReceiveFifoDepth) == 0) or if
> (HardwareFifoDepth == 0)
>
> Thank you,
> Irene
>
> -----Original Message-----
> From: Irene Park <ipark@nvidia.com>
> Sent: Tuesday, June 9, 2020 1:59 PM
> To: devel@edk2.groups.io
> Cc: Irene Park <ipark@nvidia.com>
> Subject: [PATCH v2] ArmPlatformPkg/PL011UartLib: Check PID2 if FiFoDepth
> is zero
>
> From: Irene Park <ipark@nvidia.com>
>
> PL011UartLib determines its FIFO depth based on the PID2 value but the
> register PID2 is not mandatory as per the SBSA spec.
> This change won't check PID2 if PcdUartDefaultReceiveFifoDepth is set to a
> value > 0.
>
> Signed-off-by: Irene Park <ipark@nvidia.com>
> ---
>  ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c   | 4 ++++
>  ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf | 1 +
>  2 files changed, 5 insertions(+)
>
> diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
> b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
> index 801990d..05ad1ad 100644
> --- a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
> +++ b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
> @@ -79,9 +79,13 @@ PL011UartInitializePort (
>    UINT32      Fractional;
>    UINT32      HardwareFifoDepth;
>
> +  HardwareFifoDepth = FixedPcdGet16 (PcdUartDefaultReceiveFifoDepth);
> +#if FixedPcdGet16 (PcdUartDefaultReceiveFifoDepth) == 0
>    HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase +
> UARTPID2)) \
>                         > PL011_VER_R1P4) \
>                        ? 32 : 16 ;
> +#endif
> +
>    // The PL011 supports a buffer of 1, 16 or 32 chars. Therefore we can
> accept
>    // 1 char buffer as the minimum FIFO size. Because everything can be
> rounded
>    // down, there is no maximum FIFO size.
> diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
> b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
> index d99e89f..e3da507 100644
> --- a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
> +++ b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
> @@ -30,6 +30,7 @@
>    ArmPlatformPkg/ArmPlatformPkg.dec
>
>  [FixedPcd]
> +  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultReceiveFifoDepth
>    gEfiMdeModulePkgTokenSpaceGuid.PcdSerialBaudRate
>
>    gArmPlatformTokenSpaceGuid.PL011UartInteger
> --
> 2.7.4
>
>
> 

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