From 1130106eb2cbca89724a302f8628c33875e7604f Mon Sep 17 00:00:00 2001
From: Ronald Cron <Ronald.Cron@arm.com>
Date: Thu, 16 Jul 2015 11:24:42 +0000
Subject: [PATCH] EmbeddedPkg/Lan9118Dxe: Ignore spurious RXE errors

Spurious error might appear during network transaction,
ignore them when there are not relevant.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ronald Cron <Ronald.Cron@arm.com>
Reviewed-by: Olivier Martin <Olivier.Martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18028 6f19259b-4bc3-4df7-8a09-765794883524
---
 EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c | 77 +++++++++++++--------
 1 file changed, 49 insertions(+), 28 deletions(-)

diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
index 5b7eda65c3..4de5204899 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
@@ -14,7 +14,6 @@
 
 #include "Lan9118Dxe.h"
 
-
 typedef struct {
   MAC_ADDR_DEVICE_PATH      Lan9118;
   EFI_DEVICE_PATH_PROTOCOL  End;
@@ -1312,6 +1311,7 @@ SnpReceive (
   )
 {
   LAN9118_DRIVER  *LanDriver;
+  UINT32          IntSts;
   UINT32          RxFifoStatus;
   UINT32          NumPackets;
   UINT32          RxCfgValue;
@@ -1346,6 +1346,27 @@ SnpReceive (
     return EFI_NOT_STARTED;
   }
 
+  //
+  // If the receiver raised the RXE error bit, check if the receiver status
+  // FIFO is full and if not just acknowledge the error. The two other
+  // conditions to get a RXE error are :
+  // . the RX data FIFO is read whereas being empty.
+  // . the RX status FIFO is read whereas being empty.
+  // The RX data and status FIFO are read by this driver only in the following
+  // code of this function. After the readings, the RXE error bit is checked
+  // and if raised, the controller is reset. Thus, at this point, we consider
+  // that the only valid reason to get an RXE error is the receiver status
+  // FIFO being full. And if this is not the case, we consider that this is
+  // a spurious error and we just get rid of it. We experienced such 'spurious'
+  // errors when running the driver on an A57 on Juno. No valid reason to
+  // explain those errors has been found so far and everything seems to
+  // work perfectly when they are just ignored.
+  //
+  IntSts = MmioRead32 (LAN9118_INT_STS);
+  if ((IntSts & INSTS_RXE) && (!(IntSts & INSTS_RSFF))) {
+    MmioWrite32 (LAN9118_INT_STS, INSTS_RXE);
+  }
+
   // Count dropped frames
   DroppedFrames = MmioRead32 (LAN9118_RX_DROP);
   LanDriver->Stats.RxDroppedFrames += DroppedFrames;
@@ -1453,6 +1474,33 @@ SnpReceive (
     RawData[Count] = MmioRead32 (LAN9118_RX_DATA);
   }
 
+  // Get the destination address
+  if (DstAddr != NULL) {
+    Dst.Addr[0] = (RawData[0] & 0xFF);
+    Dst.Addr[1] = (RawData[0] & 0xFF00) >> 8;
+    Dst.Addr[2] = (RawData[0] & 0xFF0000) >> 16;
+    Dst.Addr[3] = (RawData[0] & 0xFF000000) >> 24;
+    Dst.Addr[4] = (RawData[1] & 0xFF);
+    Dst.Addr[5] = (RawData[1] & 0xFF00) >> 8;
+    CopyMem (DstAddr, &Dst, NET_ETHER_ADDR_LEN);
+  }
+
+  // Get the source address
+  if (SrcAddr != NULL) {
+    Src.Addr[0] = (RawData[1] & 0xFF0000) >> 16;
+    Src.Addr[1] = (RawData[1] & 0xFF000000) >> 24;
+    Src.Addr[2] = (RawData[2] & 0xFF);
+    Src.Addr[3] = (RawData[2] & 0xFF00) >> 8;
+    Src.Addr[4] = (RawData[2] & 0xFF0000) >> 16;
+    Src.Addr[5] = (RawData[2] & 0xFF000000) >> 24;
+    CopyMem (SrcAddr, &Src, NET_ETHER_ADDR_LEN);
+  }
+
+  // Get the protocol
+  if (Protocol != NULL) {
+    *Protocol = NTOHS (RawData[3] & 0xFFFF);
+  }
+
   // Check for Rx errors (worst possible error)
   if (MmioRead32 (LAN9118_INT_STS) & INSTS_RXE) {
     DEBUG ((EFI_D_WARN, "Warning: Receiver Error. Restarting...\n"));
@@ -1481,33 +1529,6 @@ SnpReceive (
     return EFI_DEVICE_ERROR;
   }
 
-  // Get the destination address
-  if (DstAddr != NULL) {
-    Dst.Addr[0] = (RawData[0] & 0xFF);
-    Dst.Addr[1] = (RawData[0] & 0xFF00) >> 8;
-    Dst.Addr[2] = (RawData[0] & 0xFF0000) >> 16;
-    Dst.Addr[3] = (RawData[0] & 0xFF000000) >> 24;
-    Dst.Addr[4] = (RawData[1] & 0xFF);
-    Dst.Addr[5] = (RawData[1] & 0xFF00) >> 8;
-    CopyMem (DstAddr, &Dst, NET_ETHER_ADDR_LEN);
-  }
-
-  // Get the source address
-  if (SrcAddr != NULL) {
-    Src.Addr[0] = (RawData[1] & 0xFF0000) >> 16;
-    Src.Addr[1] = (RawData[1] & 0xFF000000) >> 24;
-    Src.Addr[2] = (RawData[2] & 0xFF);
-    Src.Addr[3] = (RawData[2] & 0xFF00) >> 8;
-    Src.Addr[4] = (RawData[2] & 0xFF0000) >> 16;
-    Src.Addr[5] = (RawData[2] & 0xFF000000) >> 24;
-    CopyMem (SrcAddr,&Src, NET_ETHER_ADDR_LEN);
-  }
-
-  // Get the protocol
-  if (Protocol != NULL) {
-    *Protocol = NTOHS (RawData[3] & 0xFFFF);
-  }
-
 #if defined(EVAL_PERFORMANCE)
   UINT64 EndClock = GetPerformanceCounter ();
   DEBUG ((EFI_D_ERROR, "Receive Time processing: %d counts @ %d Hz\n", StartClock - EndClock,Perf));
-- 
2.39.2