From 9a08941c1f6996357cb8167f95965ff3d009c53d Mon Sep 17 00:00:00 2001
From: gdisirio <gdisirio@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Sat, 3 Oct 2009 06:48:01 +0000
Subject: [PATCH] Fixed lockup in the experimental MAC driver.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@1199 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 demos/ARM7-AT91SAM7X-WEB-GCC/web/webthread.c |  2 +-
 os/io/platforms/AT91SAM7X/mac_lld.c          | 28 +++++++++++++-------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/demos/ARM7-AT91SAM7X-WEB-GCC/web/webthread.c b/demos/ARM7-AT91SAM7X-WEB-GCC/web/webthread.c
index ceb9ebcd1..12c3b8405 100644
--- a/demos/ARM7-AT91SAM7X-WEB-GCC/web/webthread.c
+++ b/demos/ARM7-AT91SAM7X-WEB-GCC/web/webthread.c
@@ -102,8 +102,8 @@ static void PeriodicTimerHandler(eventid_t id) {
  */
 static void ARPTimerHandler(eventid_t id) {
 
-  uip_arp_timer();
   (void)macPollLinkStatus(&ETH1);
+  uip_arp_timer();
 }
 
 /*
diff --git a/os/io/platforms/AT91SAM7X/mac_lld.c b/os/io/platforms/AT91SAM7X/mac_lld.c
index 3f3560d6a..47167fa80 100644
--- a/os/io/platforms/AT91SAM7X/mac_lld.c
+++ b/os/io/platforms/AT91SAM7X/mac_lld.c
@@ -293,6 +293,19 @@ void mac_lld_release_transmit_descriptor(MACTransmitDescriptor *tdp) {
   chSysUnlock();
 }
 
+/**
+ * @brief Cleans an incomplete frame.
+ * @param from the start position of the incomplete frame
+ */
+static void cleanup(EMACDescriptor *from) {
+
+  while (from != rxptr) {
+    from->w1 &= ~W1_R_OWNERSHIP;
+    if (++from >= &rd[EMAC_RECEIVE_DESCRIPTORS])
+      from = rd;
+  }
+}
+
 /**
  * @brief Returns a receive descriptor.
  *
@@ -337,9 +350,11 @@ skip:
 restart:
   edp = rxptr;
   while (n > 0) {
-    if (!(rxptr->w1 & W1_R_OWNERSHIP))
-      goto skip;        /* Empty buffer for some reason... */
-
+    if (!(rxptr->w1 & W1_R_OWNERSHIP)) {
+      /* Empty buffer for some reason... cleaning up the incomplete frame.*/
+      cleanup(edp);
+      goto skip;
+    }
     /*
      * End Of Frame found.
      */
@@ -352,12 +367,7 @@ restart:
 
     if ((edp != rxptr) && (rxptr->w2 & W2_R_FRAME_START)) {
       /* Found another start... cleaning up the incomplete frame.*/
-      do {
-        edp->w1 &= ~W1_R_OWNERSHIP;
-        if (++edp >= &rd[EMAC_RECEIVE_DESCRIPTORS])
-          edp = rd;
-      }
-      while (edp != rxptr);
+      cleanup(edp);
       goto restart;     /* Another start buffer for some reason... */
     }