diff --git a/src/soc/intel/alderlake/include/soc/iomap.h b/src/soc/intel/alderlake/include/soc/iomap.h
index 94fb5bee09..59019d4cce 100644
--- a/src/soc/intel/alderlake/include/soc/iomap.h
+++ b/src/soc/intel/alderlake/include/soc/iomap.h
@@ -100,6 +100,10 @@
 #define TCO_BASE_SIZE		0x20
 
 #define P2SB_BAR		CONFIG_PCR_BASE_ADDRESS
+#if CONFIG(SOC_INTEL_ALDERLAKE_PCH_S)
+#define P2SB_SIZE		(256 * MiB)
+#else
 #define P2SB_SIZE		(16 * MiB)
+#endif
 
 #endif