diff --git a/sys/dev/tpm/tpm20.h b/sys/dev/tpm/tpm20.h
index 38340c33f76..fcede6f1b60 100644
--- a/sys/dev/tpm/tpm20.h
+++ b/sys/dev/tpm/tpm20.h
@@ -153,12 +153,14 @@ RD4(struct tpm_sc *sc, bus_size_t off)
 
 	return (bus_read_4(sc->mem_res, off));
 }
+#ifdef __amd64__
 static inline uint64_t
 RD8(struct tpm_sc *sc, bus_size_t off)
 {
 
 	return (bus_read_8(sc->mem_res, off));
 }
+#endif
 static inline void
 WR1(struct tpm_sc *sc, bus_size_t off, uint8_t val)
 {
diff --git a/sys/dev/tpm/tpm_crb.c b/sys/dev/tpm/tpm_crb.c
index c48109a0238..778b208b83e 100644
--- a/sys/dev/tpm/tpm_crb.c
+++ b/sys/dev/tpm/tpm_crb.c
@@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$");
 #define TPM_CRB_CTRL_CMD_HADDR	0x60
 #define TPM_CRB_CTRL_RSP_SIZE	0x64
 #define TPM_CRB_CTRL_RSP_ADDR	0x68
+#define TPM_CRB_CTRL_RSP_HADDR	0x6c
 #define TPM_CRB_DATA_BUFFER		0x80
 
 #define TPM_LOC_STATE_ESTB			BIT(0)
@@ -188,7 +189,12 @@ tpmcrb_attach(device_t dev)
 	 * addr is stored in two 4 byte neighboring registers, whereas RSP is
 	 * stored in a single 8 byte one.
 	 */
+#ifdef __amd64__
 	crb_sc->rsp_off = RD8(sc, TPM_CRB_CTRL_RSP_ADDR);
+#else
+	crb_sc->rsp_off = RD4(sc, TPM_CRB_CTRL_RSP_ADDR);
+	crb_sc->rsp_off |= ((uint64_t) RD4(sc, TPM_CRB_CTRL_RSP_HADDR) << 32);
+#endif
 	crb_sc->cmd_off = RD4(sc, TPM_CRB_CTRL_CMD_LADDR);
 	crb_sc->cmd_off |= ((uint64_t) RD4(sc, TPM_CRB_CTRL_CMD_HADDR) << 32);
 	crb_sc->cmd_buf_size = RD4(sc, TPM_CRB_CTRL_CMD_SIZE);