intel/sandybridge: Locate CBMEM TOC early in ramstage

This patch allows the use of migrated CAR_GLOBAL variables from
the very beginning of ramstage. Without the patch, CAR_GLOBALS were
not available until northbridge set_resources().

Change-Id: Ifd4ab2ed52e07dcbe8c77e2e460dc483323e93c0
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/3513
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/northbridge/intel/sandybridge/northbridge.c b/src/northbridge/intel/sandybridge/northbridge.c
index 0a413b4..d8e2e9d 100644
--- a/src/northbridge/intel/sandybridge/northbridge.c
+++ b/src/northbridge/intel/sandybridge/northbridge.c
@@ -51,6 +51,21 @@
 	return bridge_revision_id;
 }
 
+static unsigned long get_top_of_ram(void)
+{
+	/* Base of TSEG is top of usable DRAM */
+	u32 tom = pci_read_config32(dev_find_slot(0, PCI_DEVFN(0,0)), TSEG);
+	return (unsigned long) tom;
+}
+
+struct cbmem_entry *get_cbmem_toc(void)
+{
+	static struct cbmem_entry *toc = NULL;
+	if (!toc)
+		toc = (struct cbmem_entry *)(get_top_of_ram() - HIGH_MEMORY_SIZE);
+	return toc;
+}
+
 /* Reserve everything between A segment and 1MB:
  *
  * 0xa0000 - 0xbffff: legacy VGA