ppc4xx/POST: Change ethernet test loop count to a default of 10

This patch changes the PPC4xx ethernet POST loop test count from
currently 192 (256 - 64) to a default of 10. While doing this the max
frame size is increased. Each loop run uses a different frame size,
starting with a max of 1514 bytes, down to 64. The default loop
count of 10 can be overriden using CONFIG_SYS_POST_ETH_LOOPS in the
board config header.

The TEST_NUM loop has been removed as it was never used.

The main reason for this change is to reduce the boot time on boards
using this POST test, like the lwmon5 board. This change reduces the
boot time by about 600ms on the lwmon5 board.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>

post/cpu/ppc4xx/ether.c

@@ -34,7 +34,10 @@
  * are transmitted. The configurable test parameters are:
  *   MIN_PACKET_LENGTH - minimum size of packet to transmit
  *   MAX_PACKET_LENGTH - maximum size of packet to transmit
- *   TEST_NUM - number of tests
+ *   CONFIG_SYS_POST_ETH_LOOPS - Number of test loops. Each loop
+ *     is tested with a different frame length. Starting with
+ *     MAX_PACKET_LENGTH and going down to MIN_PACKET_LENGTH.
+ *     Defaults to 10 and can be overriden in the board config header.
  */
 
 #include <post.h>
@@ -77,8 +80,12 @@ DECLARE_GLOBAL_DATA_PTR;
 #endif
 
 #define MIN_PACKET_LENGTH	64
-#define MAX_PACKET_LENGTH	256
-#define TEST_NUM		1
+#define MAX_PACKET_LENGTH	1514
+#ifndef CONFIG_SYS_POST_ETH_LOOPS
+#define CONFIG_SYS_POST_ETH_LOOPS	10
+#endif
+#define PACKET_INCR	((MAX_PACKET_LENGTH - MIN_PACKET_LENGTH) / \
+			 CONFIG_SYS_POST_ETH_LOOPS)
 
 static volatile mal_desc_t tx __cacheline_aligned;
 static volatile mal_desc_t rx __cacheline_aligned;
@@ -361,29 +368,27 @@ static int packet_check (char *packet, int length)
 	return 0;
 }
 
+	char packet_send[MAX_PACKET_LENGTH];
+	char packet_recv[MAX_PACKET_LENGTH];
 static int test_ctlr (int devnum, int hw_addr)
 {
 	int res = -1;
-	char packet_send[MAX_PACKET_LENGTH];
-	char packet_recv[MAX_PACKET_LENGTH];
 	int length;
-	int i;
 	int l;
 
 	ether_post_init (devnum, hw_addr);
 
-	for (i = 0; i < TEST_NUM; i++) {
-		for (l = MIN_PACKET_LENGTH; l <= MAX_PACKET_LENGTH; l++) {
-			packet_fill (packet_send, l);
+	for (l = MAX_PACKET_LENGTH; l >= MIN_PACKET_LENGTH;
+	     l -= PACKET_INCR) {
+		packet_fill (packet_send, l);
 
-			ether_post_send (devnum, hw_addr, packet_send, l);
+		ether_post_send (devnum, hw_addr, packet_send, l);
 
-			length = ether_post_recv (devnum, hw_addr, packet_recv,
-						  sizeof (packet_recv));
+		length = ether_post_recv (devnum, hw_addr, packet_recv,
+					  sizeof (packet_recv));
 
-			if (length != l || packet_check (packet_recv, length) < 0) {
-				goto Done;
-			}
+		if (length != l || packet_check (packet_recv, length) < 0) {
+			goto Done;
 		}
 	}