--- zzzz-none-000/linux-2.4.17/arch/mips/ddb5xxx/common/prom.c	2001-09-09 17:43:01.000000000 +0000
+++ sangam-fb-322/linux-2.4.17/arch/mips/ddb5xxx/common/prom.c	2004-11-24 13:22:39.000000000 +0000
@@ -22,6 +22,7 @@
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
 #include <asm/ddb5xxx/ddb5xxx.h>
+#include <asm/debug.h>
 
 char arcs_cmdline[COMMAND_LINE_SIZE];
 
@@ -40,19 +41,84 @@
 		strcat(arcs_cmdline, " ");
 	}
 
+	/* by default all these boards use dhcp/nfs root fs */
+	strcat(arcs_cmdline, "ip=bootp");
+
 	mips_machgroup = MACH_GROUP_NEC_DDB;
 
 #if defined(CONFIG_DDB5074)
 	mips_machtype = MACH_NEC_DDB5074;
+	add_memory_region(0, DDB_SDRAM_SIZE, BOOT_MEM_RAM);
 #elif defined(CONFIG_DDB5476)
 	mips_machtype = MACH_NEC_DDB5476;
+	add_memory_region(0, DDB_SDRAM_SIZE, BOOT_MEM_RAM);
 #elif defined(CONFIG_DDB5477)
-	mips_machtype = MACH_NEC_DDB5477;
+	ddb5477_runtime_detection();
+	add_memory_region(0, board_ram_size, BOOT_MEM_RAM);
 #endif
-
-	add_memory_region(0, DDB_SDRAM_SIZE, BOOT_MEM_RAM);
 }
 
 void __init prom_free_prom_memory(void)
 {
 }
+
+#if defined(CONFIG_DDB5477)
+
+#define DEFAULT_LCS1_BASE 0x19000000
+#define TESTVAL1 'K'
+#define TESTVAL2 'S'
+
+int board_ram_size;
+void ddb5477_runtime_detection(void)
+{
+	volatile char *test_offset;
+	char saved_test_byte;
+
+        /* Determine if this is a DDB5477 board, or a BSB-VR0300
+           base board.  We can tell by checking for the location of
+           the NVRAM.  It lives at the beginning of LCS1 on the DDB5477,
+           and the beginning of LCS1 on the BSB-VR0300 is flash memory.
+           The first 2K of the NVRAM are reserved, so don't we'll poke
+           around just after that.
+         */
+
+        test_offset = (char *)KSEG1ADDR(DEFAULT_LCS1_BASE + 0x800);
+        saved_test_byte = *test_offset;
+
+        *test_offset = TESTVAL1;
+        if (*test_offset != TESTVAL1) {
+                /* We couldn't set our test value, so it must not be NVRAM,
+                   so it's a BSB_VR0300 */
+		mips_machtype = MACH_NEC_ROCKHOPPER;
+        } else {
+                /* We may have gotten lucky, and the TESTVAL1 was already
+                   stored at the test location, so we must check a second
+                   test value */
+                *test_offset = TESTVAL2;
+                if (*test_offset != TESTVAL2) {
+                        /* OK, we couldn't set this value either, so it must
+                           definately be a BSB_VR0300 */
+			mips_machtype = MACH_NEC_ROCKHOPPER;
+                } else {
+                        /* We could change the value twice, so it must be
+                        NVRAM, so it's a DDB_VRC5477 */
+			mips_machtype = MACH_NEC_DDB5477;
+                }
+        }
+        /* Restore the original byte */
+        *test_offset = saved_test_byte;
+
+	/* before we know a better way, we will trust PMON for getting
+	 * RAM size 
+	 */
+	board_ram_size = 1 << (36 - (ddb_in32(DDB_SDRAM0) & 0xf));
+
+	db_run(printk("DDB run-time detection : %s, %d MB RAM\n",
+				mips_machtype == MACH_NEC_DDB5477 ?
+				"DDB5477" : "Rockhopper",
+				board_ram_size >> 20));
+
+	/* we can't handle ram size > 128 MB */
+	db_assert(board_ram_size <= (128 << 20));
+}
+#endif