From e79a71642524583ce1bcd252fd5675bcafb78124 Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Thu, 26 Mar 2015 22:16:31 +0100
Subject: [PATCH] software/bios/sdram: select the type of data we want to
 generate for memtest with TEST_RANDOM_DATA (debugging hardware is easier with
 a simple counter)

---
 software/bios/sdram.c | 25 +++++++++++++++++--------
 software/bios/sdram.h |  1 +
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/software/bios/sdram.c b/software/bios/sdram.c
index d374e9d3..f3dca3e4 100644
--- a/software/bios/sdram.c
+++ b/software/bios/sdram.c
@@ -423,15 +423,24 @@ int sdrlevel(void)
 #endif /* CSR_DDRPHY_BASE */
 
 #define TEST_SIZE (2*1024*1024)
+#define TEST_RANDOM_DATA 1
 
 #define ONEZERO 0xAAAAAAAA
 #define ZEROONE 0x55555555
 
+unsigned int seed_to_data(unsigned int seed, int random)
+{
+	if (random)
+		return 1664525*seed + 1013904223;
+	else
+		return seed + 1;
+}
+
 int memtest_silent(void)
 {
 	volatile unsigned int *array = (unsigned int *)MAIN_RAM_BASE;
 	int i;
-	unsigned int prv;
+	unsigned int seed;
 	unsigned int error_cnt;
 
 	/* test data bus */
@@ -453,18 +462,18 @@ int memtest_silent(void)
 			error_cnt++;
 	}
 
-	/* test random data */
-	prv = 0;
+	/* test counter or random data */
+	seed = 0;
 	for(i=0;i<TEST_SIZE/4;i++) {
-		prv = 1664525*prv + 1013904223;
-		array[i] = prv;
+		seed = seed_to_data(seed, TEST_RANDOM_DATA);
+		array[i] = seed;
 	}
 
-	prv = 0;
+	seed = 0;
 	error_cnt = 0;
 	for(i=0;i<TEST_SIZE/4;i++) {
-		prv = 1664525*prv + 1013904223;
-		if(array[i] != prv)
+		seed = seed_to_data(seed, TEST_RANDOM_DATA);
+		if(array[i] != seed)
 			error_cnt++;
 	}
 	return error_cnt;
diff --git a/software/bios/sdram.h b/software/bios/sdram.h
index c5d0984f..af20e31f 100644
--- a/software/bios/sdram.h
+++ b/software/bios/sdram.h
@@ -17,6 +17,7 @@ void sdrwloff(void);
 int sdrlevel(void);
 #endif
 
+unsigned int seed_to_data(unsigned int seed, int random);
 int memtest_silent(void);
 int memtest(void);
 int sdrinit(void);
-- 
2.30.2