ppc4xx: Enable ECC on LWMON5

Since all ECC related problems seem to be resolved on LWMON5, this patch
now enables ECC support.

We have to write the ECC bytes by zeroing and flushing in smaller
steps, since the whole 256MByte takes too long for the external
watchdog.

Signed-off-by: Stefan Roese <sr@denx.de>

board/lwmon5/sdram.c

@@ -6,7 +6,7 @@
  * Alain Saurel,	    AMCC/IBM, alain.saurel@fr.ibm.com
  * Robert Snyder,	    AMCC/IBM, rob.snyder@fr.ibm.com
  *
- * (C) Copyright 2007
+ * (C) Copyright 2007-2008
  * Stefan Roese, DENX Software Engineering, sr@denx.de.
  *
  * This program is free software; you can redistribute it and/or
@@ -35,6 +35,7 @@
 #include <asm/mmu.h>
 #include <asm/io.h>
 #include <ppc440.h>
+#include <watchdog.h>
 
 /*
  * This DDR2 setup code can dynamically setup the TLB entries for the DDR2 memory
@@ -99,87 +100,37 @@ static void wait_ddr_idle(void)
 	 */
 }
 
-static void blank_string(int size)
-{
-	int i;
-
-	for (i=0; i<size; i++)
-		putc('\b');
-	for (i=0; i<size; i++)
-		putc(' ');
-	for (i=0; i<size; i++)
-		putc('\b');
-}
-
 static void program_ecc(u32 start_address,
 			u32 num_bytes,
 			u32 tlb_word2_i_value)
 {
-	u32 current_address;
-	u32 end_address;
-	u32 address_increment;
 	u32 val;
-	char str[] = "ECC generation -";
-	char slash[] = "\\|/-\\|/-";
-	int loop = 0;
-	int loopi = 0;
-
-	current_address = start_address;
+	u32 current_addr = start_address;
+	int bytes_remaining;
 
 	sync();
-	eieio();
 	wait_ddr_idle();
 
-	if (tlb_word2_i_value == TLB_WORD2_I_ENABLE) {
-		/* ECC bit set method for non-cached memory */
-		address_increment = 4;
-		end_address = current_address + num_bytes;
-
-		puts(str);
-
-		while (current_address < end_address) {
-			*((u32 *)current_address) = 0x00000000;
-			current_address += address_increment;
-
-			if ((loop++ % (2 << 20)) == 0) {
-				putc('\b');
-				putc(slash[loopi++ % 8]);
-			}
-		}
+	/*
+	 * Because of 440EPx errata CHIP 11, we don't touch the last 256
+	 * bytes of SDRAM.
+	 */
+	bytes_remaining = num_bytes - CFG_MEM_TOP_HIDE;
 
-		blank_string(strlen(str));
-	} else {
-		/* ECC bit set method for cached memory */
-#if 0 /* test-only: will remove this define later, when ECC problems are solved! */
-		/*
-		 * Some boards (like lwmon5) need to preserve the memory
-		 * content upon ECC generation (for the log-buffer).
-		 * Therefore we don't fill the memory with a pattern or
-		 * just zero it, but write the same values back that are
-		 * already in the memory cells.
-		 */
-		address_increment = CFG_CACHELINE_SIZE;
-		end_address = current_address + num_bytes;
-
-		current_address = start_address;
-		while (current_address < end_address) {
-			/*
-			 * TODO: Th following sequence doesn't work correctly.
-			 * Just invalidating and flushing the cache doesn't
-			 * seem to trigger the re-write of the memory.
-			 */
-			ppcDcbi(current_address);
-			ppcDcbf(current_address);
-			current_address += CFG_CACHELINE_SIZE;
-		}
-#else
-		dcbz_area(start_address, num_bytes);
-		dflush();
-#endif
+	/*
+	 * We have to write the ECC bytes by zeroing and flushing in smaller
+	 * steps, since the whole 256MByte takes too long for the external
+	 * watchdog.
+	 */
+	while (bytes_remaining > 0) {
+		dcbz_area(current_addr, min((64 << 20), bytes_remaining));
+		current_addr += 64 << 20;
+		bytes_remaining -= 64 << 20;
+		WATCHDOG_RESET();
 	}
+	dflush();
 
 	sync();
-	eieio();
 	wait_ddr_idle();
 
 	/* Clear error status */
@@ -191,7 +142,6 @@ static void program_ecc(u32 start_address,
 	mtsdram(DDR0_01, ((val &~ DDR0_01_INT_MASK_MASK) | DDR0_01_INT_MASK_ALL_OFF));
 
 	sync();
-	eieio();
 	wait_ddr_idle();
 }
 #endif

include/configs/lwmon5.h

@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2007
+ * (C) Copyright 2007-2008
  * Stefan Roese, DENX Software Engineering, sr@denx.de.
  *
  * This program is free software; you can redistribute it and/or
@@ -151,12 +151,8 @@
 #define CFG_MBYTES_SDRAM	(256)		/* 256MB			*/
 #define CFG_DDR_CACHED_ADDR	0x40000000	/* setup 2nd TLB cached here	*/
 #define CONFIG_DDR_DATA_EYE	1		/* use DDR2 optimization	*/
-#if 0 /* test-only: disable ECC for now */
 #define CONFIG_DDR_ECC		1		/* enable ECC			*/
 #define CFG_POST_ECC_ON		CFG_POST_ECC
-#else
-#define CFG_POST_ECC_ON		0
-#endif
 
 /* POST support */
 #define CONFIG_POST		(CFG_POST_CACHE    | \