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

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 7/2/20 8:22 AM, Irene Park wrote:
> Hello Ard,
> Would you please kindly review this change?
> Thank you,
> Irene
> 

Merged as #753, apologies for the delay.

Please double check the version I committed - I cleaned up the code slightly


> -----Original Message-----
> From: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
> Sent: Monday, June 22, 2020 5:01 PM
> To: devel@edk2.groups.io; Irene Park <ipark@nvidia.com>; Ard Biesheuvel <Ard.Biesheuvel@arm.com>
> Subject: RE: [edk2-devel] [PATCH v2] ArmPlatformPkg/PL011UartLib: Check PID2 if FiFoDepth is zero
> 
> External email: Use caution opening links or attachments
> 
> 
> 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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