Index: linux-2.6.21-armeb/arch/arm/mach-ixp4xx/nslu2-setup.c
===================================================================
--- linux-2.6.21-armeb.orig/arch/arm/mach-ixp4xx/nslu2-setup.c	2007-05-09 07:22:17.000000000 -0700
+++ linux-2.6.21-armeb/arch/arm/mach-ixp4xx/nslu2-setup.c	2007-05-09 07:22:34.000000000 -0700
@@ -20,6 +20,7 @@
 #include <linux/leds.h>
 #include <linux/mtd/mtd.h>
 
+#include <asm/setup.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/flash.h>
@@ -231,6 +232,35 @@
     .init   = nslu2_timer_init,
 };
 
+static char nslu2_rtc_probe[] __initdata = "rtc-x1205.probe=0,0x6f ";
+
+static void __init nslu2_fixup(struct machine_desc *desc,
+                struct tag *tags, char **cmdline, struct meminfo *mi)
+{
+    struct tag *t = tags;
+    char *p = *cmdline;
+
+    /* Find the end of the tags table, taking note of any cmdline tag. */
+    for (; t->hdr.size; t = tag_next(t)) {
+        if (t->hdr.tag == ATAG_CMDLINE) {
+            p = t->u.cmdline.cmdline;
+        }
+    }
+
+    /* Overwrite the end of the table with a new cmdline tag. */
+    t->hdr.tag = ATAG_CMDLINE;
+    t->hdr.size = (sizeof (struct tag_header) +
+        strlen(nslu2_rtc_probe) + strlen(p) + 1 + 4) >> 2;
+    strlcpy(t->u.cmdline.cmdline, nslu2_rtc_probe, COMMAND_LINE_SIZE);
+    strlcpy(t->u.cmdline.cmdline + strlen(nslu2_rtc_probe), p,
+        COMMAND_LINE_SIZE - strlen(nslu2_rtc_probe));
+
+    /* Terminate the table. */
+    t = tag_next(t);
+    t->hdr.tag = ATAG_NONE;
+    t->hdr.size = 0;
+}
+
 static void __init nslu2_init(void)
 {
 	ixp4xx_sys_init();
@@ -258,6 +288,7 @@
 	.phys_io	= IXP4XX_PERIPHERAL_BASE_PHYS,
 	.io_pg_offst	= ((IXP4XX_PERIPHERAL_BASE_VIRT) >> 18) & 0xFFFC,
 	.boot_params	= 0x00000100,
+	.fixup          = nslu2_fixup,
 	.map_io		= ixp4xx_map_io,
 	.init_irq	= ixp4xx_init_irq,
 	.timer          = &nslu2_timer,