diff --git a/board-qemu/slof/Makefile b/board-qemu/slof/Makefile
index d7ed2d7..a8cff6d 100644
--- a/board-qemu/slof/Makefile
+++ b/board-qemu/slof/Makefile
@@ -22,7 +22,8 @@ CPPFLAGS = -I$(LIBCMNDIR)/libbootmsg -I$(LIBCMNDIR)/libhvcall \
 	   -I$(LIBCMNDIR)/libvirtio -I$(LIBCMNDIR)/libnvram \
 	   -I$(LIBCMNDIR)/libusb -I$(LIBCMNDIR)/libveth \
 	   -I$(LIBCMNDIR)/libe1k -I$(LIBCMNDIR)/libnet \
-	   -I$(LIBCMNDIR)/libbootmenu
+	   -I$(LIBCMNDIR)/libbootmenu -I$(LIBCMNDIR)/libtpm
+
 SLOF_LIBS = \
 	$(LIBCMNDIR)/libbootmsg.a \
 	$(LIBCMNDIR)/libelf.a \
@@ -33,7 +34,9 @@ SLOF_LIBS = \
 	$(LIBCMNDIR)/libveth.a \
 	$(LIBCMNDIR)/libe1k.a \
 	$(LIBCMNDIR)/libnet.a \
-	$(LIBCMNDIR)/libbootmenu.a
+	$(LIBCMNDIR)/libbootmenu.a \
+	$(LIBCMNDIR)/libtpm.a
+
 BOARD_SLOF_IN = \
 	$(LIBCMNDIR)/libhvcall/hvcall.in \
 	$(LIBCMNDIR)/libvirtio/virtio.in \
@@ -45,7 +48,9 @@ BOARD_SLOF_IN = \
 	$(LIBCMNDIR)/libveth/veth.in \
 	$(LIBCMNDIR)/libe1k/e1k.in \
 	$(LIBCMNDIR)/libnet/libnet.in \
-	$(LIBCMNDIR)/libbootmenu/bootmenu.in
+	$(LIBCMNDIR)/libbootmenu/bootmenu.in \
+	$(LIBCMNDIR)/libtpm/tpm.in
+
 BOARD_SLOF_CODE = $(BOARD_SLOF_IN:%.in=%.code)
 
 include $(SLOFCMNDIR)/Makefile.inc
@@ -83,6 +88,7 @@ VIO_FFS_FILES = \
 	$(SLOFBRDDIR)/pci-device_1af4_1050.fs \
 	$(SLOFBRDDIR)/vio-hvterm.fs \
 	$(SLOFBRDDIR)/vio-vscsi.fs \
+	$(SLOFBRDDIR)/vio-vtpm-cdriver.fs \
 	$(SLOFBRDDIR)/vio-veth.fs \
 	$(SLOFBRDDIR)/rtas-nvram.fs \
 	$(SLOFBRDDIR)/virtio-net.fs \
@@ -114,6 +120,7 @@ OF_FFS_FILES = \
 	$(SLOFBRDDIR)/default-font.bin \
 	$(SLOFBRDDIR)/pci-phb.fs \
 	$(SLOFBRDDIR)/rtas.fs \
+	$(SLOFBRDDIR)/vtpm-sml.fs \
 	$(SLOFBRDDIR)/pci-device_1234_1111.fs \
 	$(SLOFBRDDIR)/pci-device_1013_00b8.fs \
 	$(SLOFBRDDIR)/pci-device_8086_100e.fs \
diff --git a/board-qemu/slof/tree.fs b/board-qemu/slof/tree.fs
index d95fde3..7b34125 100644
--- a/board-qemu/slof/tree.fs
+++ b/board-qemu/slof/tree.fs
@@ -87,6 +87,9 @@ include fbuffer.fs
 	    2dup " qemu,spapr-nvram" strequal IF
 	    	" rtas-nvram.fs" included
 	    THEN
+	    2dup " IBM,vtpm20" strequal IF
+                " vio-vtpm-cdriver.fs" included
+	    THEN
             2drop
        THEN
        peer
diff --git a/board-qemu/slof/vio-vtpm-cdriver.fs b/board-qemu/slof/vio-vtpm-cdriver.fs
new file mode 100644
index 0000000..7a2ffc3
--- /dev/null
+++ b/board-qemu/slof/vio-vtpm-cdriver.fs
@@ -0,0 +1,105 @@
+\ *****************************************************************************
+\ * Copyright (c) 2015-2020 IBM Corporation
+\ * All rights reserved.
+\ * This program and the accompanying materials
+\ * are made available under the terms of the BSD License
+\ * which accompanies this distribution, and is available at
+\ * http://www.opensource.org/licenses/bsd-license.php
+\ *
+\ * Contributors:
+\ *     IBM Corporation - initial implementation
+\ ****************************************************************************/
+
+." Populating " pwd cr
+
+false VALUE vtpm-debug?
+0     VALUE vtpm-unit
+
+0     VALUE    log-base
+40000 CONSTANT LOG-SIZE   \ 256k per VTPM FW spec.
+
+e     CONSTANT VTPM_DRV_ERROR_SML_HANDED_OVER
+
+LOG-SIZE BUFFER: log-base
+
+\ firmware API call
+: sml-get-allocated-size ( -- buffer-size)
+   LOG-SIZE
+;
+
+\ firmware API call
+: sml-get-handover-size ( -- size)
+   tpm-get-logsize
+;
+
+\ firmware API call
+: sml-handover ( dest size -- )
+   log-base    ( dest size src )
+   -rot        ( src dest size )
+   move
+
+   VTPM_DRV_ERROR_SML_HANDED_OVER tpm-driver-set-failure-reason
+;
+
+\ firmware API call
+: get-failure-reason ( -- reason )
+   tpm-driver-get-failure-reason           ( reason )
+;
+
+0 0 s" ibm,sml-efi-reformat-supported" property
+
+\ firmware API call
+: reformat-sml-to-efi-alignment ( -- success )
+   true
+;
+
+: open true ;
+: close ;
+
+: vtpm-cleanup ( -- )
+   vtpm-debug? IF ." VTPM: Disabling RTAS bypass" cr THEN
+   tpm-finalize
+   \ Disable TCE bypass
+   vtpm-unit 0 rtas-set-tce-bypass
+;
+
+: vtpm-init ( -- success )
+   0 0 get-node open-node ?dup 0= IF false EXIT THEN
+   my-self >r
+   dup to my-self
+
+   vtpm-debug? IF ." VTPM: Initializing for c-driver" cr THEN
+
+   my-unit to vtpm-unit
+
+   \ Enable TCE bypass special qemu feature
+   vtpm-unit 1 rtas-set-tce-bypass
+
+   \ Have TCE bypass cleaned up
+   ['] vtpm-cleanup add-quiesce-xt
+
+   \ close temporary node
+   close-node
+   r> to my-self
+
+   tpm-start ?dup 0= IF
+      vtpm-debug? IF ." VTPM: Success from tpm-start" cr THEN
+      true
+   ELSE
+      ." VTPM: Error code from tpm-start: " . cr
+      false
+   THEN
+;
+
+\ inititialize unit and set RTAS bypass
+vtpm-init IF
+   \ pass logbase and size to the C driver; we may only do this after
+   \ init of the lower levels since this calls needs to know the PCR banks
+   \ when setting up the log
+   log-base LOG-SIZE tpm-set-log-parameters
+   s" vtpm-sml.fs" included
+ELSE
+   ." VTPM: vtpm-init failed" cr
+THEN
+
+
diff --git a/board-qemu/slof/vtpm-sml.fs b/board-qemu/slof/vtpm-sml.fs
new file mode 100644
index 0000000..8e2ab6d
--- /dev/null
+++ b/board-qemu/slof/vtpm-sml.fs
@@ -0,0 +1,68 @@
+\ *****************************************************************************
+\ * Copyright (c) 2015-2020 IBM Corporation
+\ * All rights reserved.
+\ * This program and the accompanying materials
+\ * are made available under the terms of the BSD License
+\ * which accompanies this distribution, and is available at
+\ * http://www.opensource.org/licenses/bsd-license.php
+\ *
+\ * Contributors:
+\ *     IBM Corporation - initial implementation
+\ ****************************************************************************/
+
+" /" find-device
+
+new-device
+
+false VALUE    vtpm-debug?
+
+\ create /ibm,vtpm
+s" ibm,vtpm" 2dup device-name device-type
+
+\
+\ only internal API calls
+\
+
+: separator-event ( start-pcr end-pcr -- )
+    tpm-add-event-separators                   ( errcode )
+    ?dup IF
+        ." VTPM: Error code from tpm-add-event-separators: " . cr
+    THEN
+;
+
+80 CONSTANT BCV_DEVICE_HDD
+
+: measure-hdd-mbr ( addr length -- )
+    0 7 separator-event
+    BCV_DEVICE_HDD                             ( addr length bootdrv )
+    -rot                                       ( bootdrv addr length )
+    tpm-measure-bcv-mbr                        ( errcode )
+    ?dup IF
+        ." VTPM: Error code from tpm-measure-hdd: " . cr
+    THEN
+;
+
+: leave-firmware ( -- )
+    tpm-leave-firmware                         ( errcode )
+    ?dup IF
+        ." VTPM: Error code from tpm-leave-firmware: " . cr
+    THEN
+;
+
+: measure-scrtm ( -- )
+    tpm-measure-scrtm                          ( errcode )
+    ?dup IF
+        ." VTPM: Error code from tpm-measure-scrtm: " . cr
+    THEN
+;
+
+: open  true ;
+: close ;
+
+finish-device
+device-end
+
+s" /ibm,vtpm" find-node ?dup IF
+  s" measure-scrtm" rot $call-static
+THEN
+
diff --git a/include/helpers.h b/include/helpers.h
index 2f460d6..47b2674 100644
--- a/include/helpers.h
+++ b/include/helpers.h
@@ -50,5 +50,6 @@ extern unsigned long SLOF_get_vtpm_unit(void);
 #define container_of(ptr, type, member) ({                      \
 			const typeof(((type *)0)->member)* struct_ptr = (ptr); \
 			(type *)((char *)struct_ptr - offset_of(type, member)); })
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
 
 #endif
diff --git a/lib/libtpm/Makefile b/lib/libtpm/Makefile
index 8fa781e..bcfe88d 100644
--- a/lib/libtpm/Makefile
+++ b/lib/libtpm/Makefile
@@ -23,7 +23,7 @@ TARGET = ../libtpm.a
 
 all: $(TARGET)
 
-SRCS = tpm_drivers.c sha256.c
+SRCS = tpm_drivers.c sha256.c tcgbios.c
 
 OBJS = $(SRCS:%.c=%.o)
 
diff --git a/lib/libtpm/tcgbios.c b/lib/libtpm/tcgbios.c
new file mode 100644
index 0000000..d81d392
--- /dev/null
+++ b/lib/libtpm/tcgbios.c
@@ -0,0 +1,925 @@
+/*****************************************************************************
+ * Copyright (c) 2015-2020 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *     Stefan Berger, stefanb@linux.ibm.com
+ *     Kevin O'Connor, kevin@koconnor.net
+ *****************************************************************************/
+
+/*
+ *  Implementation of the TPM BIOS extension according to the specification
+ *  described in the IBM VTPM Firmware document and the TCG Specification
+ *  that can be found here under the following link:
+ *  https://trustedcomputinggroup.org/resource/pc-client-work-group-specific-implementation-specification-for-conventional-bios/
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "types.h"
+#include "byteorder.h"
+#include "tpm_drivers.h"
+#include "string.h"
+#include "tcgbios.h"
+#include "tcgbios_int.h"
+#include "stdio.h"
+#include "sha256.h"
+#include "helpers.h"
+#include "version.h"
+#include "OF.h"
+
+#undef TCGBIOS_DEBUG
+//#define TCGBIOS_DEBUG
+#ifdef TCGBIOS_DEBUG
+#define dprintf(_x ...) do { printf("TCGBIOS: " _x); } while(0)
+#else
+#define dprintf(_x ...)
+#endif
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+static struct {
+	unsigned tpm_probed:1;
+	unsigned tpm_found:1;
+	unsigned tpm_working:1;
+
+	/* base address of the log area */
+	uint8_t *log_base;
+
+	/* size of the logging area */
+	size_t log_area_size;
+
+	/* where to write the next log entry to */
+	uint8_t *log_area_next_entry;
+
+	/* PCR selection as received from TPM */
+	uint32_t tpm20_pcr_selection_size;
+	struct tpml_pcr_selection *tpm20_pcr_selection;
+} tpm_state;
+
+/*
+ * TPM 2 logs are written in little endian format.
+ */
+static inline uint32_t log32_to_cpu(uint32_t val)
+{
+	return le32_to_cpu(val);
+}
+
+static inline uint32_t cpu_to_log32(uint32_t val)
+{
+	return cpu_to_le32(val);
+}
+
+static inline uint16_t cpu_to_log16(uint16_t val)
+{
+	return cpu_to_le16(val);
+}
+
+/********************************************************
+  Extensions for TCG-enabled BIOS
+ *******************************************************/
+
+static void probe_tpm(void)
+{
+	tpm_state.tpm_probed = true;
+	tpm_state.tpm_found = spapr_is_vtpm_present();
+	tpm_state.tpm_working = tpm_state.tpm_found;
+}
+
+/****************************************************************
+ * Digest formatting
+ ****************************************************************/
+
+/* A 'struct tpm_log_entry' is a local data structure containing a
+ * 'TCG_PCR_EVENT2_Header' followed by space for the maximum supported
+ * digest. The digest is a series of TPMT_HA structs on tpm2.0.
+ */
+struct tpm_log_entry {
+	TCG_PCR_EVENT2_Header hdr;
+	uint8_t pad[sizeof(struct TPML_DIGEST_VALUES)
+	   + 5 * sizeof(struct TPMT_HA)
+	   + SHA1_BUFSIZE + SHA256_BUFSIZE + SHA384_BUFSIZE
+	   + SHA512_BUFSIZE + SM3_256_BUFSIZE];
+} __attribute__((packed));
+
+static const struct hash_parameters {
+	uint16_t hashalg;
+	uint8_t  hash_buffersize;
+} hash_parameters[] = {
+	{
+		.hashalg = TPM2_ALG_SHA1,
+		.hash_buffersize = SHA1_BUFSIZE,
+	}, {
+		.hashalg = TPM2_ALG_SHA256,
+		.hash_buffersize = SHA256_BUFSIZE,
+	}, {
+		.hashalg = TPM2_ALG_SHA384,
+		.hash_buffersize = SHA384_BUFSIZE,
+	}, {
+		.hashalg = TPM2_ALG_SHA512,
+		.hash_buffersize = SHA512_BUFSIZE,
+	}, {
+		.hashalg = TPM2_ALG_SM3_256,
+		.hash_buffersize = SM3_256_BUFSIZE,
+	}
+};
+
+static const struct hash_parameters *tpm20_find_by_hashalg(uint16_t hashAlg)
+{
+	unsigned i;
+
+	for (i = 0; i < ARRAY_SIZE(hash_parameters); i++) {
+		if (hash_parameters[i].hashalg == hashAlg)
+			return &hash_parameters[i];
+	}
+	return NULL;
+}
+
+static inline int tpm20_get_hash_buffersize(uint16_t hashAlg)
+{
+	const struct hash_parameters *hp = tpm20_find_by_hashalg(hashAlg);
+
+	if (hp)
+		return hp->hash_buffersize;
+	return -1;
+}
+
+/*
+ * Build the TPM2 TPML_DIGEST_VALUES data structure from the given hash.
+ * Follow the PCR bank configuration of the TPM and write the same hash
+ * in either truncated or zero-padded form in the areas of all the other
+ * hashes. For example, write the sha256 hash in the area of the sha384
+ * hash and fill the remaining bytes with zeros. Or truncate the sha256
+ * hash when writing it in the area of the sha1 hash.
+ *
+ * le: the log entry to build the digest in
+ * sha1: the sha1 hash value to use
+ * bigEndian: whether to build in big endian format for the TPM or log
+ *            little endian for the log (TPM 2.0)
+ *
+ * Returns the digest size; -1 on fatal error
+ */
+static int tpm20_build_digest(struct tpm_log_entry *le, const uint8_t *sha256,
+			      bool bigEndian)
+{
+	struct tpms_pcr_selection *sel;
+	void *nsel, *end;
+	void *dest = le->hdr.digests + sizeof(struct TPML_DIGEST_VALUES);
+	uint32_t count;
+	struct TPMT_HA *v;
+	struct TPML_DIGEST_VALUES *vs;
+
+	sel = tpm_state.tpm20_pcr_selection->selections;
+	end = (void *)tpm_state.tpm20_pcr_selection +
+		tpm_state.tpm20_pcr_selection_size;
+
+	for (count = 0;
+	     count < be32_to_cpu(tpm_state.tpm20_pcr_selection->count);
+	     count++) {
+		int hsize;
+		uint8_t sizeOfSelect = sel->sizeOfSelect;
+
+		nsel = (void*)sel + sizeof(*sel) + sizeOfSelect;
+		if (nsel > end)
+			break;
+
+		hsize = tpm20_get_hash_buffersize(be16_to_cpu(sel->hashAlg));
+		if (hsize < 0) {
+			dprintf("TPM is using an unsupported hash: %d\n",
+				be16_to_cpu(sel->hashAlg));
+			return -1;
+		}
+
+		/* buffer size sanity check before writing */
+		v = dest;
+		if (dest + sizeof(*v) + hsize > (void*)le + sizeof(*le)) {
+			dprintf("tpm_log_entry is too small\n");
+			return -1;
+		}
+
+		if (bigEndian)
+			v->hashAlg = sel->hashAlg;
+		else
+			v->hashAlg = cpu_to_le16(be16_to_cpu(sel->hashAlg));
+
+		memset(v->hash, 0, hsize);
+		memcpy(v->hash, sha256,
+		       hsize < SHA256_BUFSIZE ? hsize : SHA256_BUFSIZE);
+
+		dest += sizeof(*v) + hsize;
+		sel = nsel;
+	}
+
+	if (sel != end) {
+		dprintf("Malformed pcr selection structure fron TPM\n");
+		return -1;
+	}
+
+	vs = (void*)le->hdr.digests;
+	if (bigEndian)
+		vs->count = cpu_to_be32(count);
+	else
+		vs->count = cpu_to_le32(count);
+
+	return dest - (void*)le->hdr.digests;
+}
+
+/****************************************************************
+ * TPM hardware command wrappers
+ ****************************************************************/
+
+/* Helper function for sending TPM commands that take a single
+ * optional parameter (0, 1, or 2 bytes) and have no special response.
+ */
+static int
+tpm_simple_cmd(uint8_t locty, uint32_t ordinal, int param_size, uint16_t param,
+	       enum tpm_duration_type to_t)
+{
+	struct {
+		struct tpm_req_header trqh;
+		uint16_t param;
+	} __attribute__((packed)) req = {
+		.trqh.totlen = cpu_to_be32(sizeof(req.trqh) + param_size),
+		.trqh.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+		.trqh.ordinal = cpu_to_be32(ordinal),
+	};
+	uint8_t obuffer[64];
+	struct tpm_rsp_header *trsh = (void *)obuffer;
+	uint32_t obuffer_len = sizeof(obuffer);
+	int ret;
+
+	switch (param_size) {
+	case 2:
+		req.param = cpu_to_be16(param);
+		break;
+	case 1:
+		*(uint8_t *)&req.param = param;
+		break;
+	}
+
+	memset(obuffer, 0, sizeof(obuffer));
+	ret = spapr_transmit(locty, &req.trqh, obuffer, &obuffer_len, to_t);
+	ret = ret ? -1 : be32_to_cpu(trsh->errcode);
+	dprintf("Return from tpm_simple_cmd(%x, %x) = %x\n",
+		ordinal, param, ret);
+
+	return ret;
+}
+
+static int
+tpm20_getcapability(uint32_t capability, uint32_t property, uint32_t count,
+	            struct tpm_rsp_header *rsp, uint32_t rsize)
+{
+	struct tpm2_req_getcapability trg = {
+		.hdr.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+		.hdr.totlen = cpu_to_be32(sizeof(trg)),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_GetCapability),
+		.capability = cpu_to_be32(capability),
+		.property = cpu_to_be32(property),
+		.propertycount = cpu_to_be32(count),
+	};
+	uint32_t resp_size = rsize;
+	int ret;
+
+	ret = spapr_transmit(0, &trg.hdr, rsp, &resp_size,
+			     TPM_DURATION_TYPE_SHORT);
+	ret = (ret ||
+	       rsize < be32_to_cpu(rsp->totlen)) ? -1
+						 : be32_to_cpu(rsp->errcode);
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_GetCapability = 0x%08x\n",
+		ret);
+
+	return ret;
+}
+
+static int
+tpm20_get_pcrbanks(void)
+{
+	uint8_t buffer[128];
+	uint32_t size;
+	struct tpm2_res_getcapability *trg =
+		(struct tpm2_res_getcapability *)&buffer;
+	uint32_t resplen;
+	int ret;
+
+	ret = tpm20_getcapability(TPM2_CAP_PCRS, 0, 8, &trg->hdr,
+				  sizeof(buffer));
+	if (ret)
+		return ret;
+
+	/* defend against (broken) TPM sending packets that are too short */
+	resplen = be32_to_cpu(trg->hdr.totlen);
+	if (resplen <= offset_of(struct tpm2_res_getcapability, data))
+		return -1;
+
+	size = resplen - offset_of(struct tpm2_res_getcapability, data);
+	/* we need a valid tpml_pcr_selection up to and including sizeOfSelect*/
+	if (size < offset_of(struct tpml_pcr_selection, selections) +
+		   offset_of(struct tpms_pcr_selection, pcrSelect))
+		return -1;
+
+	tpm_state.tpm20_pcr_selection = SLOF_alloc_mem(size);
+	if (tpm_state.tpm20_pcr_selection) {
+		memcpy(tpm_state.tpm20_pcr_selection, &trg->data, size);
+		tpm_state.tpm20_pcr_selection_size = size;
+	} else {
+		printf("TCGBIOS: Failed to allocated %u bytes.\n", size);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int tpm20_extend(struct tpm_log_entry *le, int digest_len)
+{
+	struct tpm2_req_extend tmp_tre = {
+		.hdr.tag     = cpu_to_be16(TPM2_ST_SESSIONS),
+		.hdr.totlen  = cpu_to_be32(0),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_PCR_Extend),
+		.pcrindex    = cpu_to_be32(log32_to_cpu(le->hdr.pcrindex)),
+		.authblocksize = cpu_to_be32(sizeof(tmp_tre.authblock)),
+		.authblock = {
+			.handle = cpu_to_be32(TPM2_RS_PW),
+			.noncesize = cpu_to_be16(0),
+			.contsession = TPM2_YES,
+			.pwdsize = cpu_to_be16(0),
+		},
+	};
+	uint8_t buffer[sizeof(tmp_tre) + sizeof(le->pad)];
+	struct tpm2_req_extend *tre = (struct tpm2_req_extend *)buffer;
+	struct tpm_rsp_header rsp;
+	uint32_t resp_length = sizeof(rsp);
+	int ret;
+
+	memcpy(tre, &tmp_tre, sizeof(tmp_tre));
+	memcpy(&tre->digest[0], le->hdr.digests, digest_len);
+
+	tre->hdr.totlen = cpu_to_be32(sizeof(tmp_tre) + digest_len);
+
+	ret = spapr_transmit(0, &tre->hdr, &rsp, &resp_length,
+			     TPM_DURATION_TYPE_SHORT);
+	if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+		return -1;
+
+	return 0;
+}
+
+static int tpm20_stirrandom(void)
+{
+	struct tpm2_req_stirrandom stir = {
+		.hdr.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+		.hdr.totlen = cpu_to_be32(sizeof(stir)),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_StirRandom),
+		.size = cpu_to_be16(sizeof(stir.stir)),
+		.stir = rand(),
+	};
+	struct tpm_rsp_header rsp;
+	uint32_t resp_length = sizeof(rsp);
+	int ret = spapr_transmit(0, &stir.hdr, &rsp, &resp_length,
+				 TPM_DURATION_TYPE_SHORT);
+
+	if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+		ret = -1;
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_StirRandom = 0x%08x\n",
+		ret);
+
+	return ret;
+}
+
+static int tpm20_getrandom(uint8_t *buf, uint16_t buf_len)
+{
+	struct tpm2_res_getrandom rsp;
+	struct tpm2_req_getrandom trgr = {
+		.hdr.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+		.hdr.totlen = cpu_to_be32(sizeof(trgr)),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_GetRandom),
+		.bytesRequested = cpu_to_be16(buf_len),
+	};
+	uint32_t resp_length = sizeof(rsp);
+	int ret;
+
+	if (buf_len > sizeof(rsp.rnd.buffer))
+		return -1;
+
+	ret = spapr_transmit(0, &trgr.hdr, &rsp, &resp_length,
+			     TPM_DURATION_TYPE_MEDIUM);
+	if (ret || resp_length != sizeof(rsp) || rsp.hdr.errcode)
+		ret = -1;
+	else
+		memcpy(buf, rsp.rnd.buffer, buf_len);
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_GetRandom = 0x%08x\n",
+		ret);
+
+	return ret;
+}
+
+static int tpm20_hierarchychangeauth(uint8_t auth[20])
+{
+	struct tpm2_req_hierarchychangeauth trhca = {
+		.hdr.tag = cpu_to_be16(TPM2_ST_SESSIONS),
+		.hdr.totlen = cpu_to_be32(sizeof(trhca)),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_HierarchyChangeAuth),
+		.authhandle = cpu_to_be32(TPM2_RH_PLATFORM),
+		.authblocksize = cpu_to_be32(sizeof(trhca.authblock)),
+		.authblock = {
+			.handle = cpu_to_be32(TPM2_RS_PW),
+			.noncesize = cpu_to_be16(0),
+			.contsession = TPM2_YES,
+			.pwdsize = cpu_to_be16(0),
+		},
+		.newAuth = {
+			.size = cpu_to_be16(sizeof(trhca.newAuth.buffer)),
+		},
+	};
+	struct tpm_rsp_header rsp;
+	uint32_t resp_length = sizeof(rsp);
+	int ret;
+
+	memcpy(trhca.newAuth.buffer, auth, sizeof(trhca.newAuth.buffer));
+
+	ret = spapr_transmit(0, &trhca.hdr, &rsp, &resp_length,
+			     TPM_DURATION_TYPE_MEDIUM);
+	if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+		ret = -1;
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_HierarchyChangeAuth = 0x%08x\n",
+		ret);
+
+	return ret;
+}
+
+static int tpm20_hierarchycontrol(uint32_t hierarchy, uint8_t state)
+{
+	struct tpm2_req_hierarchycontrol trh = {
+		.hdr.tag = cpu_to_be16(TPM2_ST_SESSIONS),
+		.hdr.totlen = cpu_to_be32(sizeof(trh)),
+		.hdr.ordinal = cpu_to_be32(TPM2_CC_HierarchyControl),
+		.authhandle = cpu_to_be32(TPM2_RH_PLATFORM),
+		.authblocksize = cpu_to_be32(sizeof(trh.authblock)),
+		.authblock = {
+			.handle = cpu_to_be32(TPM2_RS_PW),
+			.noncesize = cpu_to_be16(0),
+			.contsession = TPM2_YES,
+			.pwdsize = cpu_to_be16(0),
+		},
+		.enable = cpu_to_be32(hierarchy),
+		.state = state,
+	};
+	struct tpm_rsp_header rsp;
+	uint32_t resp_length = sizeof(rsp);
+	int ret;
+
+	ret = spapr_transmit(0, &trh.hdr, &rsp, &resp_length,
+			     TPM_DURATION_TYPE_MEDIUM);
+	if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+		ret = -1;
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_HierarchyControl = 0x%08x\n",
+		ret);
+
+	return ret;
+}
+
+/****************************************************************
+ * Setup and Measurements
+ ****************************************************************/
+
+bool tpm_is_working(void)
+{
+	if (!tpm_state.tpm_probed)
+		probe_tpm();
+
+	return tpm_state.tpm_working;
+}
+
+static void tpm_set_failure(void)
+{
+	tpm20_hierarchycontrol(TPM2_RH_ENDORSEMENT, TPM2_NO);
+	tpm20_hierarchycontrol(TPM2_RH_OWNER, TPM2_NO);
+
+	tpm_state.tpm_working = false;
+}
+
+/*
+ * Extend the OFDT log with the given entry by copying the
+ * entry data into the log.
+ *
+ * @pcpes: Pointer to the structure to be copied into the log
+ * @event: The event to be appended to 'pcpes'
+ * @event_length: The length of the event
+ *
+ * Returns 0 on success, an error code otherwise.
+ */
+static uint32_t tpm_log_event_long(TCG_PCR_EVENT2_Header *entry,
+				   int digest_len,
+				   const void *event, uint32_t event_length)
+{
+	size_t size, logsize;
+	void *dest;
+	TCG_PCR_EVENT2_Trailer *t;
+
+	dprintf("log base address = %p, next entry = %p\n",
+		tpm_state.log_base, tpm_state.log_area_next_entry);
+
+	if (tpm_state.log_area_next_entry == NULL)
+		return TCGBIOS_LOGOVERFLOW;
+
+	size = sizeof(*entry) + digest_len +
+	       sizeof(TCG_PCR_EVENT2_Trailer) + event_length;
+	logsize = (tpm_state.log_area_next_entry + size -
+	           tpm_state.log_base);
+	if (logsize > tpm_state.log_area_size) {
+		dprintf("TCGBIOS: LOG OVERFLOW: size = %zu\n", size);
+		return TCGBIOS_LOGOVERFLOW;
+	}
+
+	dest = tpm_state.log_area_next_entry;
+	memcpy(dest, entry, sizeof(*entry) + digest_len);
+
+	t = dest + sizeof(*entry) + digest_len;
+	t->eventdatasize = cpu_to_log32(event_length);
+	if (event_length)
+		memcpy(t->event, event, event_length);
+
+	tpm_state.log_area_next_entry += size;
+
+	return 0;
+}
+
+/* Add an entry at the start of the log describing digest formats
+ */
+static int tpm20_write_EfiSpecIdEventStruct(void)
+{
+	struct {
+		struct TCG_EfiSpecIdEventStruct hdr;
+		uint32_t pad[256];
+	} event = {
+		.hdr.signature = "Spec ID Event03",
+		.hdr.platformClass = TPM_TCPA_ACPI_CLASS_CLIENT,
+		.hdr.specVersionMinor = 0,
+		.hdr.specVersionMajor = 2,
+		.hdr.specErrata = 0,
+		.hdr.uintnSize = 2,
+	};
+	struct tpms_pcr_selection *sel;
+	void *nsel, *end;
+	int event_size;
+	uint32_t *vendorInfoSize;
+	struct tpm_log_entry le = {
+		.hdr.eventtype = cpu_to_log32(EV_NO_ACTION),
+	};
+	uint32_t count;
+
+	sel = tpm_state.tpm20_pcr_selection->selections;
+	end = (void*)tpm_state.tpm20_pcr_selection +
+	      tpm_state.tpm20_pcr_selection_size;
+
+	for (count = 0;
+	     count < be32_to_cpu(tpm_state.tpm20_pcr_selection->count);
+	     count++) {
+		int hsize;
+		uint8_t sizeOfSelect = sel->sizeOfSelect;
+
+		nsel = (void*)sel + sizeof(*sel) + sizeOfSelect;
+		if (nsel > end)
+			break;
+
+		hsize = tpm20_get_hash_buffersize(be16_to_cpu(sel->hashAlg));
+		if (hsize < 0) {
+			dprintf("TPM is using an unsupported hash: %d\n",
+				be16_to_cpu(sel->hashAlg));
+			return -1;
+		}
+
+		event_size = offset_of(struct TCG_EfiSpecIdEventStruct,
+				       digestSizes[count+1]);
+		if (event_size > sizeof(event) - sizeof(uint32_t)) {
+			dprintf("EfiSpecIdEventStruct pad too small\n");
+			return -1;
+		}
+
+		event.hdr.digestSizes[count].algorithmId =
+			cpu_to_log16(be16_to_cpu(sel->hashAlg));
+		event.hdr.digestSizes[count].digestSize = cpu_to_log16(hsize);
+
+		sel = nsel;
+	}
+
+	if (sel != end) {
+		dprintf("Malformed pcr selection structure fron TPM\n");
+		return -1;
+	}
+
+	event.hdr.numberOfAlgorithms = cpu_to_log32(count);
+	event_size = offset_of(struct TCG_EfiSpecIdEventStruct,
+			       digestSizes[count]);
+	vendorInfoSize = (void*)&event + event_size;
+	*vendorInfoSize = 0;
+	event_size += sizeof(*vendorInfoSize);
+
+	return tpm_log_event_long(&le.hdr, SHA1_BUFSIZE, &event, event_size);
+}
+
+static int tpm20_startup(void)
+{
+	int ret;
+
+	ret = tpm_simple_cmd(0, TPM2_CC_Startup,
+			     2, TPM2_SU_CLEAR, TPM_DURATION_TYPE_SHORT);
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_Startup(SU_CLEAR) = 0x%08x\n",
+		ret);
+
+	if (ret)
+		goto err_exit;
+
+	ret = tpm_simple_cmd(0, TPM2_CC_SelfTest,
+			     1, TPM2_YES, TPM_DURATION_TYPE_LONG);
+
+	dprintf("TCGBIOS: Return value from sending TPM2_CC_SELF_TEST = 0x%08x\n",
+		ret);
+
+	if (ret)
+		goto err_exit;
+
+	ret = tpm20_get_pcrbanks();
+	if (ret)
+		goto err_exit;
+
+	/* the log parameters will be passed from Forth layer */
+
+	return 0;
+
+err_exit:
+	dprintf("TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+
+	tpm_set_failure();
+	return -1;
+}
+
+uint32_t tpm_start(void)
+{
+	probe_tpm();
+
+	if (!tpm_is_working()) {
+		dprintf("%s: Machine does not have a working TPM\n",
+			__func__);
+		return TCGBIOS_FATAL_COM_ERROR;
+	}
+
+	return tpm20_startup();
+}
+
+void tpm_finalize(void)
+{
+	spapr_vtpm_finalize();
+}
+
+static void tpm20_prepboot(void)
+{
+	uint8_t auth[20];
+	int ret;
+
+	ret = tpm20_stirrandom();
+	if (ret)
+		 goto err_exit;
+
+	ret = tpm20_getrandom(&auth[0], sizeof(auth));
+	if (ret)
+		goto err_exit;
+
+	ret = tpm20_hierarchychangeauth(auth);
+	if (ret)
+		goto err_exit;
+
+	return;
+
+err_exit:
+	dprintf("TCGBIOS: TPM malfunctioning (line %d).\n", __LINE__);
+
+	tpm_set_failure();
+}
+
+/*
+ * Prepare TPM for boot; this function has to be called before
+ * the firmware transitions to the boot loader.
+ */
+uint32_t tpm_leave_firmware(void)
+{
+	tpm20_prepboot();
+
+	return 0;
+}
+
+/****************************************************************
+ * Forth interface
+ ****************************************************************/
+
+void tpm_set_log_parameters(void *addr, size_t size)
+{
+	int ret;
+
+	dprintf("Log is at 0x%llx; size is %zu bytes\n",
+		(uint64_t)addr, size);
+	tpm_state.log_base = addr;
+	tpm_state.log_area_next_entry = addr;
+	tpm_state.log_area_size = size;
+
+	ret = tpm20_write_EfiSpecIdEventStruct();
+	if (ret)
+		tpm_set_failure();
+}
+
+uint32_t tpm_get_logsize(void)
+{
+	uint32_t logsize = tpm_state.log_area_next_entry - tpm_state.log_base;
+
+	dprintf("log size: %u\n", logsize);
+
+	return logsize;
+}
+
+/*
+ * Add a measurement to the log;
+ *
+ * Input parameters:
+ *  @pcrindex : PCR to extend
+ *  @event_type : type of event
+ *  @info : pointer to info (i.e., string) to be added to the log as-is
+ *  @info_length: length of the info
+ *  @hashdata : pointer to data to be hashed
+ *  @hashdata_length: length of the data
+ *
+ */
+static uint32_t tpm_add_measurement_to_log(uint32_t pcrindex,
+					   uint32_t eventtype,
+					   const char *info,
+					   uint32_t infolen,
+					   const uint8_t *hashdata,
+					   uint32_t hashdatalen)
+{
+	uint8_t hash[SHA256_BUFSIZE];
+	struct tpm_log_entry le = {
+		.hdr.pcrindex = cpu_to_log32(pcrindex),
+		.hdr.eventtype = cpu_to_log32(eventtype),
+	};
+	int digest_len;
+	int ret;
+
+	sha256(hashdata, hashdatalen, hash);
+	digest_len = tpm20_build_digest(&le, hash, true);
+	if (digest_len < 0)
+		return TCGBIOS_GENERAL_ERROR;
+	ret = tpm20_extend(&le, digest_len);
+	if (ret) {
+		tpm_set_failure();
+		return TCGBIOS_COMMAND_ERROR;
+	}
+	tpm20_build_digest(&le, hash, false);
+	return tpm_log_event_long(&le.hdr, digest_len, info, infolen);
+}
+
+/*
+ * Add an EV_ACTION measurement to the list of measurements
+ */
+static uint32_t tpm_add_action(uint32_t pcrIndex, const char *string)
+{
+	uint32_t len = strlen(string);
+
+	return tpm_add_measurement_to_log(pcrIndex, EV_ACTION,
+					  string, len, (uint8_t *)string, len);
+}
+
+/*
+ * Add event separators for a range of PCRs
+ */
+uint32_t tpm_add_event_separators(uint32_t start_pcr, uint32_t end_pcr)
+{
+	static const uint8_t evt_separator[] = {0xff,0xff,0xff,0xff};
+	uint32_t pcrIndex;
+	int rc;
+
+	if (!tpm_is_working())
+		return TCGBIOS_GENERAL_ERROR;
+
+	if (start_pcr >= 24 || start_pcr > end_pcr)
+		return TCGBIOS_INVALID_INPUT_PARA;
+
+	/* event separators need to be extended and logged for PCRs 0-7 */
+	for (pcrIndex = start_pcr; pcrIndex <= end_pcr; pcrIndex++) {
+		rc = tpm_add_measurement_to_log(pcrIndex, EV_SEPARATOR,
+						NULL, 0,
+						evt_separator,
+						sizeof(evt_separator));
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+uint32_t tpm_measure_bcv_mbr(uint32_t bootdrv, const uint8_t *addr,
+			     uint32_t length)
+{
+	uint32_t rc;
+	const char *string;
+
+	if (!tpm_is_working())
+		return TCGBIOS_GENERAL_ERROR;
+
+	if (length < 0x200)
+		return TCGBIOS_INVALID_INPUT_PARA;
+
+	string = "Booting BCV device 00h (Floppy)";
+	if (bootdrv == BCV_DEVICE_HDD)
+		string = "Booting BCV device 80h (HDD)";
+
+	rc = tpm_add_action(4, string);
+	if (rc)
+		return rc;
+
+	/*
+	 * equivalent to: dd if=/dev/hda ibs=1 count=440 | sha256sum
+	 */
+	string = "MBR";
+	rc = tpm_add_measurement_to_log(4, EV_IPL,
+					string, strlen(string),
+					addr, 0x1b8);
+	if (rc)
+		return rc;
+
+	/*
+	 * equivalent to: dd if=/dev/hda ibs=1 count=72 skip=440 | sha256sum
+	 */
+	string = "MBR PARTITION TABLE";
+	return tpm_add_measurement_to_log(5, EV_IPL_PARTITION_DATA,
+					  string, strlen(string),
+					  addr + 0x1b8, 0x48);
+}
+
+uint32_t tpm_measure_scrtm(void)
+{
+	uint32_t rc;
+	char *version_start = strstr((char *)&print_version, "FW Version");
+	char *version_end;
+	uint32_t version_length;
+	char *slof_text_start = (char *)&_slof_text;
+	uint32_t slof_text_length = (long)&_slof_text_end - (long)&_slof_text;
+	const char *scrtm = "S-CRTM Contents";
+
+	version_end = strchr(version_start, '\r');
+	version_length = version_end - version_start;
+
+	dprintf("Measure S-CRTM Version: addr = %p, length = %d\n",
+		version_start, version_length);
+
+	rc = tpm_add_measurement_to_log(0, EV_S_CRTM_VERSION,
+					version_start, version_length,
+					(uint8_t *)version_start,
+					version_length);
+	if (rc)
+		return rc;
+
+	dprintf("Measure S-CRTM Content (text): start = %p, length = %d\n",
+		slof_text_start, slof_text_length);
+
+	rc = tpm_add_measurement_to_log(0, EV_S_CRTM_CONTENTS,
+					scrtm, strlen(scrtm),
+					(uint8_t *)slof_text_start,
+					slof_text_length);
+
+	return rc;
+}
+
+/*
+ * tpm_driver_get_failure_reason: Function for interfacing with the firmware
+ *                                API
+ */
+uint32_t tpm_driver_get_failure_reason(void)
+{
+	/* do not check for a working TPM here */
+	if (!tpm_state.tpm_found)
+		return VTPM_DRV_STATE_INVALID;
+
+	return spapr_vtpm_get_error();
+}
+
+/*
+ * tpm_driver_set_failure_reason: Function for interfacing with the firmware
+ *                                API
+ */
+void tpm_driver_set_failure_reason(uint32_t errcode)
+{
+	if (!tpm_state.tpm_found)
+		return;
+
+	spapr_vtpm_set_error(errcode);
+}
diff --git a/lib/libtpm/tcgbios.h b/lib/libtpm/tcgbios.h
new file mode 100644
index 0000000..e9f9c36
--- /dev/null
+++ b/lib/libtpm/tcgbios.h
@@ -0,0 +1,32 @@
+/*****************************************************************************
+ * Copyright (c) 2015-2020 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+
+#ifndef TCGBIOS_H
+#define TCGBIOS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+uint32_t tpm_start(void);
+void tpm_finalize(void);
+uint32_t tpm_leave_firmware(void);
+uint32_t tpm_measure_scrtm(void);
+void tpm_set_log_parameters(void *address, size_t size);
+uint32_t tpm_get_logsize(void);
+uint32_t tpm_measure_bcv_mbr(uint32_t bootdrv, const uint8_t *addr,
+                             uint32_t length);
+uint32_t tpm_add_event_separators(uint32_t start_pcr, uint32_t end_pcr);
+uint32_t tpm_driver_get_failure_reason(void);
+void tpm_driver_set_failure_reason(uint32_t errcode);
+bool tpm_is_working(void);
+
+#endif /* TCGBIOS_H */
diff --git a/lib/libtpm/tcgbios_int.h b/lib/libtpm/tcgbios_int.h
index 835bd36..6892e6f 100644
--- a/lib/libtpm/tcgbios_int.h
+++ b/lib/libtpm/tcgbios_int.h
@@ -15,6 +15,83 @@
 
 #include <stdint.h>
 
+/* internal error codes */
+#define TCGBIOS_OK                       0x0
+#define TCGBIOS_LOGOVERFLOW              0x1
+#define TCGBIOS_GENERAL_ERROR            0x2
+#define TCGBIOS_FIRMWARE_ERROR           0x3
+#define TCGBIOS_FATAL_COM_ERROR          0x4
+#define TCGBIOS_INVALID_INPUT_PARA       0x5
+#define TCGBIOS_COMMAND_ERROR            0x6
+#define TCGBIOS_INTERFACE_SHUTDOWN       0x7
+
+/*
+ * event types from spec:
+ * TCG PC Client Specific Implementation Specification
+ * for Conventional BIOS
+ */
+#define EV_POST_CODE                     1
+#define EV_NO_ACTION                     3
+#define EV_SEPARATOR                     4
+#define EV_ACTION                        5
+#define EV_EVENT_TAG                     6
+#define EV_S_CRTM_CONTENTS               7
+#define EV_S_CRTM_VERSION                8
+#define EV_IPL                          13
+#define EV_IPL_PARTITION_DATA           14
+
+#define BCV_DEVICE_HDD                  0x80
+
+/* hash sizes */
+#define SHA1_BUFSIZE                    20
+#define SHA256_BUFSIZE                  32
+#define SHA384_BUFSIZE                  48
+#define SHA512_BUFSIZE                  64
+#define SM3_256_BUFSIZE                 32
+
+/*
+ * Logging for TPM 2 is specified in TCG spec "TCG PC Client Platform
+ * Firmware Profile Specification" in section "Event Logging" and sub-
+ * section "TCG_PCR_EVENT2 structure"
+ *
+ * Each entry in the TPM log contains: a TCG_PCR_EVENT2_Header, a variable
+ * length digest, a TCG_PCR_EVENT2_Trailer, and a variable length event.
+ * The 'digest' matches what is sent to the TPM hardware via the Extend
+ * command. On TPM2.0 the digest contains a TPML_DIGEST_VALUES struct
+ * followed by a variable number of TPMT_HA structs (as specified by the
+ * hardware via the TPM2_CAP_PCRS request).
+ */
+typedef struct tdTCG_PCR_EVENT2_Header {
+	uint32_t pcrindex;
+	uint32_t eventtype;
+	uint8_t digests[0];
+} __attribute__((packed)) TCG_PCR_EVENT2_Header;
+
+typedef struct tdTCG_PCR_EVENT2_Trailer {
+	uint32_t eventdatasize;
+	uint8_t event[0];
+} __attribute__((packed)) TCG_PCR_EVENT2_Trailer;
+
+struct TCG_EfiSpecIdEventStruct {
+	uint8_t signature[16];
+	uint32_t platformClass;
+#define TPM_TCPA_ACPI_CLASS_CLIENT 0
+	uint8_t specVersionMinor;
+	uint8_t specVersionMajor;
+	uint8_t specErrata;
+	uint8_t uintnSize;
+	uint32_t numberOfAlgorithms;
+	struct TCG_EfiSpecIdEventAlgorithmSize {
+		uint16_t algorithmId;
+		uint16_t digestSize;
+	} digestSizes[0];
+	/*
+	uint8_t vendorInfoSize;
+	uint8_t vendorInfo[0];
+	*/
+} __attribute__((packed));
+
+/* Input and Output headers for all TPM commands */
 struct tpm_req_header {
 	uint16_t tag;
 	uint32_t totlen;
@@ -27,4 +104,168 @@ struct tpm_rsp_header {
 	uint32_t errcode;
 } __attribute__((packed));
 
+/****************************************************************
+ * TPM v2.0 hardware commands
+ *
+ * Relevant specs for #defines and commonly used structures:
+ * - Trusted Platform Module Library; Part 2: Structures
+ * Relevant specs for command structures:
+ * - Trusted Platform Module Library; Part 3: Commands
+ ****************************************************************/
+
+#define TPM2_NO                     0
+#define TPM2_YES                    1
+
+#define TPM2_SU_CLEAR               0x0000
+#define TPM2_SU_STATE               0x0001
+
+#define TPM2_RH_OWNER               0x40000001
+#define TPM2_RS_PW                  0x40000009
+#define TPM2_RH_ENDORSEMENT         0x4000000b
+#define TPM2_RH_PLATFORM            0x4000000c
+
+#define TPM2_ALG_SHA1               0x0004
+#define TPM2_ALG_SHA256             0x000b
+#define TPM2_ALG_SHA384             0x000c
+#define TPM2_ALG_SHA512             0x000d
+#define TPM2_ALG_SM3_256            0x0012
+
+/* TPM 2 command tags */
+#define TPM2_ST_NO_SESSIONS         0x8001
+#define TPM2_ST_SESSIONS            0x8002
+
+/* TPM 2 commands */
+#define TPM2_CC_HierarchyControl    0x121
+#define TPM2_CC_Clear               0x126
+#define TPM2_CC_ClearControl        0x127
+#define TPM2_CC_HierarchyChangeAuth 0x129
+#define TPM2_CC_PCR_Allocate        0x12b
+#define TPM2_CC_SelfTest            0x143
+#define TPM2_CC_Startup             0x144
+#define TPM2_CC_Shutdown            0x145
+#define TPM2_CC_StirRandom          0x146
+#define TPM2_CC_GetCapability       0x17a
+#define TPM2_CC_GetRandom           0x17b
+#define TPM2_CC_PCR_Extend          0x182
+
+/* TPM 2 Capabilities */
+#define TPM2_CAP_PCRS               0x00000005
+
+/* TPM 2 data structures */
+
+struct TPMT_HA {
+	uint16_t hashAlg;
+	uint8_t hash[0]; /* size depends on hashAlg */
+} __attribute__((packed));
+
+struct TPML_DIGEST_VALUES {
+	uint32_t count;
+	struct TPMT_HA digest[0]; /* variable number of entries */
+} __attribute__((packed));
+
+struct tpm2_req_stirrandom {
+	struct tpm_req_header hdr;
+	uint16_t size;
+	uint64_t stir;
+} __attribute__((packed));
+
+struct tpm2_req_getrandom {
+	struct tpm_req_header hdr;
+	uint16_t bytesRequested;
+} __attribute__((packed));
+
+struct tpm2b_20 {
+	uint16_t size;
+	uint8_t buffer[20];
+} __attribute__((packed));
+
+struct tpm2_res_getrandom {
+	struct tpm_rsp_header hdr;
+	struct tpm2b_20 rnd;
+} __attribute__((packed));
+
+/*
+ * tpm2_authblock is used in TPM 2 commands using 'Auth. Handle'
+ */
+struct tpm2_authblock {
+	uint32_t handle;
+	uint16_t noncesize;  /* always 0 */
+	uint8_t contsession; /* always TPM2_YES */
+	uint16_t pwdsize;    /* always 0 */
+} __attribute__((packed));
+
+struct tpm2_req_hierarchychangeauth {
+	struct tpm_req_header hdr;
+	uint32_t authhandle;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+	struct tpm2b_20 newAuth;
+} __attribute__((packed));
+
+struct tpm2_req_extend {
+	struct tpm_req_header hdr;
+	uint32_t pcrindex;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+	uint8_t digest[0];
+} __attribute__((packed));
+
+struct tpm2_req_clearcontrol {
+	struct tpm_req_header hdr;
+	uint32_t authhandle;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+	uint8_t disable;
+} __attribute__((packed));
+
+struct tpm2_req_clear {
+	struct tpm_req_header hdr;
+	uint32_t authhandle;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+} __attribute__((packed));
+
+struct tpm2_req_hierarchycontrol {
+	struct tpm_req_header hdr;
+	uint32_t authhandle;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+	uint32_t enable;
+	uint8_t state;
+} __attribute__((packed));
+
+struct tpm2_req_getcapability {
+	struct tpm_req_header hdr;
+	uint32_t capability;
+	uint32_t property;
+	uint32_t propertycount;
+} __attribute__((packed));
+
+struct tpm2_res_getcapability {
+	struct tpm_rsp_header hdr;
+	uint8_t moreData;
+	uint32_t capability;
+	uint8_t data[0]; /* capability dependent data */
+} __attribute__((packed));
+
+struct tpm2_req_pcr_allocate {
+	struct tpm_req_header hdr;
+	uint32_t authhandle;
+	uint32_t authblocksize;
+	struct tpm2_authblock authblock;
+	uint32_t count;
+	uint8_t tpms_pcr_selections[4];
+} __attribute__((packed));
+
+struct tpms_pcr_selection {
+	uint16_t hashAlg;
+	uint8_t sizeOfSelect;
+	uint8_t pcrSelect[0];
+} __attribute__((packed));
+
+struct tpml_pcr_selection {
+	uint32_t count;
+	struct tpms_pcr_selection selections[0];
+} __attribute__((packed));
+
 #endif /* TCGBIOS_INT_H */
diff --git a/lib/libtpm/tpm.code b/lib/libtpm/tpm.code
new file mode 100644
index 0000000..05f4547
--- /dev/null
+++ b/lib/libtpm/tpm.code
@@ -0,0 +1,130 @@
+/******************************************************************************
+ * Copyright (c) 2015-2020 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+/*
+ * libtpm bindings for SLOF - implementation
+ */
+
+#include <tcgbios.h>
+#include <stdbool.h>
+
+/************************************************/
+/* Startup TPM code                             */
+/* SLOF:   tpm-start  ( -- errcode )            */
+/* LIBTPM: tpm_start(void)                      */
+/************************************************/
+PRIM(tpm_X2d_start)
+	PUSH;
+	TOS.n = tpm_start();
+MIRP
+
+/************************************************/
+/* Shutdown TPM layer before OS takes over      */
+/* SLOF:   tpm-finalize  ( -- )                 */
+/* LIBTPM: tpm_finalize(void)                   */
+/************************************************/
+PRIM(tpm_X2d_finalize)
+	tpm_finalize();
+MIRP
+
+/***************************************************************/
+/* Prepare TPM state for bootloader                            */
+/* SLOF:   tpm-leave-firwmare  ( -- errcode )                  */
+/* LIBTPM: tpm_leave_firmware(void)                            */
+/***************************************************************/
+PRIM(tpm_X2d_leave_X2d_firmware)
+	PUSH;
+	TOS.n = tpm_leave_firmware();
+MIRP
+
+/*************************************************************/
+/* Convey log address and size                               */
+/* SLOF:   tpm-set-log-parameters  ( addr size -- )          */
+/* LIBTPM: tpm_set_log_parameters(void *addr, uint64_t size) */
+/*************************************************************/
+PRIM(tpm_X2d_set_X2d_log_X2d_parameters)
+	int size = TOS.u; POP;
+	void *addr = TOS.a; POP;
+	tpm_set_log_parameters(addr, size);
+MIRP
+
+/*********************************************************/
+/* Firmware API                                          */
+/* SLOF:   tpm-driver-get_failure-reason ( -- errcode)   */
+/* LIBTPM: errcode = tpm_driver_get_failure_reason(void) */
+/*********************************************************/
+PRIM(tpm_X2d_driver_X2d_get_X2d_failure_X2d_reason)
+	PUSH;
+	TOS.n = tpm_driver_get_failure_reason();
+MIRP
+
+/********************************************************/
+/* Firmware API                                         */
+/* SLOF:   tpm-driver-set-failure_reason ( errcode -- ) */
+/* LIBTPM: tpm_driver_set_failure_reason(errcode)       */
+/********************************************************/
+PRIM(tpm_X2d_driver_X2d_set_X2d_failure_X2d_reason)
+	int errcode = TOS.u; POP;
+	tpm_driver_set_failure_reason(errcode);
+MIRP
+
+/************************************************/
+/* Get the size of the log                      */
+/* SLOF:   tpm-get-logsize         ( -- size )  */
+/* LIBTPM: logsize = tpm_get_logsize(void)      */
+/************************************************/
+PRIM(tpm_X2d_get_X2d_logsize)
+	PUSH;
+	TOS.n = tpm_get_logsize();
+MIRP
+
+/**********************************************************************/
+/* Measure and log event separators                                   */
+/* SLOF:   tpm-add-event-separators  ( start-pcr end-pcr -- errcode)  */
+/* LIBTPM: errcode = tpm_add_event_separators(start_pcr, end_pcr)     */
+/**********************************************************************/
+PRIM(tpm_X2d_add_X2d_event_X2d_separators)
+	int end_pcr = TOS.u; POP;
+	int start_pcr = TOS.u;
+	TOS.n = tpm_add_event_separators(start_pcr, end_pcr);
+MIRP
+
+/*************************************************************************/
+/* Measure and log boot connect vector (bcv) device's master boot record */
+/* SLOF:   tpm-measure-bcv-mbr  ( bootdrv addr length -- errcode )       */
+/* LIBTPM: errcode = tpm_measure_bcv_mbr(bbotdrv, addr, length)          */
+/*************************************************************************/
+PRIM(tpm_X2d_measure_X2d_bcv_X2d_mbr)
+	int length = TOS.u; POP;
+	void *addr = TOS.a; POP;
+	int bootdrv = TOS.u;
+	TOS.n = tpm_measure_bcv_mbr(bootdrv, addr, length);
+MIRP
+
+/************************************************/
+/* Check whether the TPM is working             */
+/* SLOF:   tpm-is-working  ( -- true | false )  */
+/* LIBTPM: bool = tpm_is_working()              */
+/************************************************/
+PRIM(tpm_X2d_is_X2d_working)
+	PUSH;
+	TOS.n = tpm_is_working();
+MIRP
+
+/************************************************/
+/* Have the S-CRTM measured                     */
+/* SLOF:   tpm-measure-scrtm  ( -- errcode )    */
+/* LIBTPM: errcode = tpm_measure_scrtm          */
+/************************************************/
+PRIM(tpm_X2d_measure_X2d_scrtm)
+	PUSH;
+	TOS.n = tpm_measure_scrtm();
+MIRP
diff --git a/lib/libtpm/tpm.in b/lib/libtpm/tpm.in
new file mode 100644
index 0000000..22713e4
--- /dev/null
+++ b/lib/libtpm/tpm.in
@@ -0,0 +1,26 @@
+/******************************************************************************
+ * Copyright (c) 2015-2020 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+/*
+ * libtpm bindings for SLOF - definitions
+ */
+
+cod(tpm-start)
+cod(tpm-finalize)
+cod(tpm-leave-firmware)
+cod(tpm-set-log-parameters)
+cod(tpm-get-logsize)
+cod(tpm-add-event-separators)
+cod(tpm-measure-bcv-mbr)
+cod(tpm-is-working)
+cod(tpm-measure-scrtm)
+cod(tpm-driver-get-failure-reason)
+cod(tpm-driver-set-failure-reason)
diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs
index 8859fb0..252a44e 100644
--- a/slof/fs/packages/disk-label.fs
+++ b/slof/fs/packages/disk-label.fs
@@ -338,6 +338,14 @@ CONSTANT /gpt-part-entry
    dup c@ eb = swap 2+ c@ 90 = and
 ;
 
+: measure-mbr ( addr length -- )
+   s" /ibm,vtpm" find-node ?dup IF
+      s" measure-hdd-mbr" rot $call-static
+   ELSE
+      2drop
+   THEN
+;
+
 \ NOTE: block-size is always 512 bytes for DOS partition tables.
 
 : load-from-dos-boot-partition ( addr -- size )
@@ -361,6 +369,7 @@ CONSTANT /gpt-part-entry
             block-size * to part-offset
             0 0 seek drop            ( addr offset )
             block-size * read        ( size )
+            block block-size measure-mbr
             UNLOOP EXIT
          ELSE
             2drop                    ( addr )
diff --git a/slof/fs/start-up.fs b/slof/fs/start-up.fs
index 7020f5c..c1f931a 100644
--- a/slof/fs/start-up.fs
+++ b/slof/fs/start-up.fs
@@ -56,6 +56,11 @@
 ;
 
 : (boot?) ( -- )
+   \ last step before we boot we give up physical presence on the TPM
+   s" /ibm,vtpm" find-node ?dup IF
+      s" leave-firmware" rot $call-static
+   THEN
+
    of-prompt? not auto-boot? and IF
       (boot)
    THEN
