diff --git a/src/soc/intel/broadwell/memmap.c b/src/soc/intel/broadwell/memmap.c
index 7c53fa6..f4a9d0e 100644
--- a/src/soc/intel/broadwell/memmap.c
+++ b/src/soc/intel/broadwell/memmap.c
@@ -16,12 +16,12 @@
 #define __SIMPLE_DEVICE__
 
 #include <cbmem.h>
+#include <cpu/x86/smm.h>
 #include <device/pci.h>
 #include <device/pci_ops.h>
 #include <soc/pci_devs.h>
 #include <soc/systemagent.h>
 #include <soc/smm.h>
-#include <stage_cache.h>
 #include <stdint.h>
 
 static uintptr_t dpr_region_start(void)
@@ -46,14 +46,13 @@
 	return (void *) dpr_region_start();
 }
 
-void stage_cache_external_region(void **base, size_t *size)
+void smm_region(uintptr_t *start, size_t *size)
 {
-	/* The ramstage cache lives in the TSEG region.
-	 * The top of RAM is defined to be the TSEG base address. */
-	u32 offset = smm_region_size();
-	offset -= CONFIG_IED_REGION_SIZE;
-	offset -= CONFIG_SMM_RESERVED_SIZE;
+	uintptr_t tseg = pci_read_config32(PCI_DEV(0, 0, 0), TSEG);
+	uintptr_t bgsm = pci_read_config32(PCI_DEV(0, 0, 0), BGSM);
 
-	*base = (void *)(cbmem_top() + offset);
-	*size = CONFIG_SMM_RESERVED_SIZE;
+	tseg = ALIGN_DOWN(tseg, 1 * MiB);
+	bgsm = ALIGN_DOWN(bgsm, 1 * MiB);
+	*start = tseg;
+	*size = bgsm - tseg;
 }