ArmPlatformPkg/PL011UartLib: Check PID2 if FiFoDepth is zero

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 <[email protected]> Reviewed-by: Ard Biesheuvel <[email protected]>
shenglei10 · Jul 2, 2020 · c8edb70 · c8edb70
1 parent 00217f1
commit c8edb70
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
@@ -78,10 +78,14 @@ PL011UartInitializePort (
   UINT32      Integer;
   UINT32      Fractional;
   UINT32      HardwareFifoDepth;
+  UINT32      UartPid2;
+
+  HardwareFifoDepth = FixedPcdGet16 (PcdUartDefaultReceiveFifoDepth);
+  if (HardwareFifoDepth == 0) {
+    UartPid2 = MmioRead32 (UartBase + UARTPID2);
+    HardwareFifoDepth = (PL011_UARTPID2_VER (UartPid2) > PL011_VER_R1P4) ? 32 : 16;
+  }
 
-  HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) \
-                       > PL011_VER_R1P4) \
-                      ? 32 : 16 ;
   // 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
@@ -30,6 +30,7 @@
   ArmPlatformPkg/ArmPlatformPkg.dec
 
 [FixedPcd]
+  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultReceiveFifoDepth
   gEfiMdeModulePkgTokenSpaceGuid.PcdSerialBaudRate
 
   gArmPlatformTokenSpaceGuid.PL011UartInteger