ppc4xx: Canyonlands-NAND-boot: Support 2 Crucial 512MByte SODIMM's

Some Canyonlands boards are equipped with different SODIMM's. This is no
problem with the "normal" NOR booting Canyonlands U-Boot, since it
automatically detects the SODIMM's via SPD data and correctly configures
them. But the NAND booting version is different. Here we only have 4k
of image size to completely setup the hardware, including DDR2 setup.
So we need to use a fixed DDR2 setup here. This doesn't work for different
SODIMM's right now.

Currently only this Crucial SODIMM is support:
CT6464AC667.8FB (dual ranked)

Now some boards are shipped with this SODIMM:
CT6464AC667.4FE (single ranked)

This patch now supports both SODIMM's by configuring first for the dual
ranked DIMM. A quick shows, if this module is really installed. If this test
fails, the DDR2 controller is re-configured for the single
ranked SODIMM.

Tested with those SODIMM's:

CT6464AC667.8FB (dual ranked)
CT6464AC667.4FE (single ranked)

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

nand_spl/board/amcc/canyonlands/ddr2_fixed.c

@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2008
+ * (C) Copyright 2008-2009
  * Stefan Roese, DENX Software Engineering, sr@denx.de.
  *
  * See file CREDITS for list of people who contributed to this
@@ -26,6 +26,17 @@
 #include <asm/io.h>
 #include <asm/processor.h>
 
+/*
+ * This code can configure those two Crucial SODIMM's:
+ *
+ * Crucial CT6464AC667.4FE - 512MB SO-DIMM (single rank)
+ * Crucial CT6464AC667.8FB - 512MB SO-DIMM (dual rank)
+ *
+ */
+
+#define TEST_ADDR	0x10000000
+#define TEST_MAGIC	0x11223344
+
 static void wait_init_complete(void)
 {
 	u32 val;
@@ -35,7 +46,13 @@ static void wait_init_complete(void)
 	} while (!(val & 0x80000000));
 }
 
-phys_size_t initdram(int board_type)
+static void ddr_start(void)
+{
+	mtsdram(SDRAM_MCOPT2, 0x28000000);
+	wait_init_complete();
+}
+
+static void ddr_init_common(void)
 {
 	/*
 	 * Reset the DDR-SDRAM controller.
@@ -49,17 +66,12 @@ phys_size_t initdram(int board_type)
 	 * enabled. This will only work for the same memory
 	 * configuration as used here:
 	 *
-	 * Crucial CT6464AC667.8FB - 512MB SO-DIMM
-	 *
 	 */
 	mtsdram(SDRAM_MCOPT2, 0x00000000);
-	mtsdram(SDRAM_MCOPT1, 0x05122000);
 	mtsdram(SDRAM_MODT0, 0x01000000);
-	mtsdram(SDRAM_CODT, 0x02800021);
 	mtsdram(SDRAM_WRDTR, 0x82000823);
 	mtsdram(SDRAM_CLKTR, 0x40000000);
 	mtsdram(SDRAM_MB0CF, 0x00000201);
-	mtsdram(SDRAM_MB1CF, 0x00000201);
 	mtsdram(SDRAM_RTR, 0x06180000);
 	mtsdram(SDRAM_SDTR1, 0x80201000);
 	mtsdram(SDRAM_SDTR2, 0x42103243);
@@ -82,17 +94,56 @@ phys_size_t initdram(int board_type)
 	mtsdram(SDRAM_INITPLR13, 0x80810040);
 	mtsdram(SDRAM_INITPLR14, 0x00000000);
 	mtsdram(SDRAM_INITPLR15, 0x00000000);
-
-	mtsdram(SDRAM_MCOPT2, 0x28000000);
-
-	wait_init_complete();
+	mtsdram(SDRAM_RDCC, 0x40000000);
+	mtsdram(SDRAM_RQDC, 0x80000038);
+	mtsdram(SDRAM_RFDC, 0x00000257);
 
 	mtdcr(SDRAM_R0BAS, 0x0000F800);		/* MQ0_B0BAS */
 	mtdcr(SDRAM_R1BAS, 0x0400F800);		/* MQ0_B1BAS */
+}
 
-	mtsdram(SDRAM_RDCC, 0x40000000);
-	mtsdram(SDRAM_RQDC, 0x80000038);
-	mtsdram(SDRAM_RFDC, 0x00000257);
+phys_size_t initdram(int board_type)
+{
+	/*
+	 * First try init for this module:
+	 *
+	 * Crucial CT6464AC667.8FB - 512MB SO-DIMM (dual rank)
+	 */
+
+	ddr_init_common();
+
+	/*
+	 * Crucial CT6464AC667.8FB - 512MB SO-DIMM
+	 */
+	mtdcr(SDRAM_R0BAS, 0x0000F800);
+	mtdcr(SDRAM_R1BAS, 0x0400F800);
+	mtsdram(SDRAM_MCOPT1, 0x05122000);
+	mtsdram(SDRAM_CODT, 0x02800021);
+	mtsdram(SDRAM_MB1CF, 0x00000201);
+
+	ddr_start();
+
+	/*
+	 * Now test if the dual-ranked module is really installed
+	 * by checking an address in the upper 256MByte region
+	 */
+	out_be32((void *)TEST_ADDR, TEST_MAGIC);
+	if (in_be32((void *)TEST_ADDR) != TEST_MAGIC) {
+		/*
+		 * The test failed, so we assume that the single
+		 * ranked module is installed:
+		 *
+		 * Crucial CT6464AC667.4FE - 512MB SO-DIMM (single rank)
+		 */
+
+		ddr_init_common();
+
+		mtdcr(SDRAM_R0BAS, 0x0000F000);
+		mtsdram(SDRAM_MCOPT1, 0x05322000);
+		mtsdram(SDRAM_CODT, 0x00800021);
+
+		ddr_start();
+	}
 
 	return CONFIG_SYS_MBYTES_SDRAM << 20;
 }