From: Evan Lloyd <evan.lloyd@arm.com>
Date: Wed, 21 Sep 2016 20:33:13 +0000 (+0100)
Subject: ArmPlatformPkg: Fix PL011 FIFO size test
X-Git-Tag: edk2-stable201903~5643
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=719a347c5df53a1dca6f80e06a285424228436e1

ArmPlatformPkg: Fix PL011 FIFO size test

This change updates PL011UartInitializePort to compare ReceiveFifoDepth
with the correct hardware FIFO size instead of the constant 32 used
previously.
This corrects a minor bug where a request for a fifo size > 15 and < 32
would not have been honoured on a system with a 16 byte FIFO.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---

diff --git a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
index 3748972acb..b3ea138bf6 100644
--- a/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
+++ b/ArmPlatformPkg/Drivers/PL011Uart/PL011Uart.c
@@ -79,17 +79,18 @@ PL011UartInitializePort (
   UINT32      Divisor;
   UINT32      Integer;
   UINT32      Fractional;
+  UINT32      HardwareFifoDepth;
 
+  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.
-  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= 32)) {
+  if ((*ReceiveFifoDepth == 0) || (*ReceiveFifoDepth >= HardwareFifoDepth)) {
     // Enable FIFO
     LineControl = PL011_UARTLCR_H_FEN;
-    if (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) > PL011_VER_R1P4)
-      *ReceiveFifoDepth = 32;
-    else
-      *ReceiveFifoDepth = 16;
+    *ReceiveFifoDepth = HardwareFifoDepth;
   } else {
     // Disable FIFO
     LineControl = 0;