security/tpm: replace CONFIG(TPMx) checks with runtime check

This prepares the code for enabling both CONFIG_TPM1 and CONFIG_TPM2
during compilation, in which case actual TPM family in use can be
determined at runtime.

In some places both compile-time and runtime checks are necessary.
Yet in places like probe functions runtime state checks don't make sense
as runtime state is defined by results of probing.

Change-Id: Id9cc25aad8d1d7bfad12b7a92059b1b3641bbfa9
Ticket: https://ticket.coreboot.org/issues/433
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69161
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

13 files changed, 153 insertions, 70 deletions

diff --git a/src/acpi/acpi.c b/src/acpi/acpi.c
index 98c8ecdc13..30a07bfda0 100644
--- a/src/acpi/acpi.c
+++ b/src/acpi/acpi.c
@@ -25,7 +25,9 @@
 #include <device/device.h>
 #include <device/mmio.h>
 #include <device/pci.h>
+#include <drivers/crb/tpm.h>
 #include <drivers/uart/pl011.h>
+#include <security/tpm/tss.h>
 #include <string.h>
 #include <types.h>
 #include <version.h>
@@ -205,7 +207,7 @@ static void *get_tcpa_log(u32 *size)
 
 static void acpi_create_tcpa(acpi_header_t *header, void *unused)
 {
-	if (!CONFIG(TPM1))
+	if (tlcl_get_family() != TPM_1)
 		return;
 
 	acpi_tcpa_t *tcpa = (acpi_tcpa_t *)header;
@@ -251,7 +253,7 @@ static void *get_tpm2_log(u32 *size)
 
 static void acpi_create_tpm2(acpi_header_t *header, void *unused)
 {
-	if (!CONFIG(TPM2))
+	if (tlcl_get_family() != TPM_2)
 		return;
 
 	acpi_tpm2_t *tpm2 = (acpi_tpm2_t *)header;
@@ -271,7 +273,7 @@ static void acpi_create_tpm2(acpi_header_t *header, void *unused)
 
 	/* Hard to detect for coreboot. Just set it to 0 */
 	tpm2->platform_class = 0;
-	if (CONFIG(CRB_TPM)) {
+	if (CONFIG(CRB_TPM) && tpm2_has_crb_active()) {
 		/* Must be set to 7 for CRB Support */
 		tpm2->control_area = CONFIG_CRB_TPM_BASE_ADDRESS + 0x40;
 		tpm2->start_method = 7;
diff --git a/src/drivers/crb/tis.c b/src/drivers/crb/tis.c
index 21a7647108..04e255aa7f 100644
--- a/src/drivers/crb/tis.c
+++ b/src/drivers/crb/tis.c
@@ -142,6 +142,9 @@ static int smbios_write_type43_tpm(struct device *dev, int *handle, unsigned lon
 	uint32_t fw_ver1, fw_ver2;
 	uint8_t major_spec_ver, minor_spec_ver;
 
+	if (tlcl_get_family() == TPM_1)
+		return 0;
+
 	tpm2_get_info(&info);
 
 	/* If any of these have invalid values, assume TPM not present or disabled */
diff --git a/src/drivers/crb/tpm.c b/src/drivers/crb/tpm.c
index 4e9f6f2d2b..b568dcc7f4 100644
--- a/src/drivers/crb/tpm.c
+++ b/src/drivers/crb/tpm.c
@@ -320,3 +320,29 @@ void tpm2_get_info(struct tpm2_info *tpm2_info)
 	tpm2_info->device_id = (interfaceReg >> 32) & 0xFFFF;
 	tpm2_info->revision = (interfaceReg >> 24) & 0xFF;
 }
+
+/*
+ * tpm2_has_crb_active
+ *
+ * Checks that CRB interface is available and active.
+ *
+ * The body was derived from crb_probe() which unlike this function can also
+ * write to registers.
+ */
+bool tpm2_has_crb_active(void)
+{
+	uint64_t tpmStatus = read64(CRB_REG(0, CRB_REG_INTF_ID));
+	printk(BIOS_SPEW, "Interface ID Reg. %llx\n", tpmStatus);
+
+	if ((tpmStatus & CRB_INTF_REG_CAP_CRB) == 0) {
+		printk(BIOS_DEBUG, "TPM: CRB Interface is not supported.\n");
+		return false;
+	}
+
+	if ((tpmStatus & (0xf)) != 1) {
+		printk(BIOS_DEBUG, "TPM: CRB Interface is not active.\n");
+		return false;
+	}
+
+	return true;
+}
diff --git a/src/drivers/crb/tpm.h b/src/drivers/crb/tpm.h
index 7b25e78b3b..60020c3ff9 100644
--- a/src/drivers/crb/tpm.h
+++ b/src/drivers/crb/tpm.h
@@ -64,3 +64,4 @@ tpm_result_t tpm2_init(void);
 void tpm2_get_info(struct tpm2_info *tpm2_info);
 size_t tpm2_process_command(const void *tpm2_command, size_t command_size,
 			    void *tpm2_response, size_t max_response);
+bool tpm2_has_crb_active(void);
diff --git a/src/drivers/pc80/tpm/tis.c b/src/drivers/pc80/tpm/tis.c
index da443d3a09..568065c654 100644
--- a/src/drivers/pc80/tpm/tis.c
+++ b/src/drivers/pc80/tpm/tis.c
@@ -809,7 +809,7 @@ static void lpc_tpm_fill_ssdt(const struct device *dev)
 	acpigen_write_scope(path);
 	acpigen_write_device(acpi_device_name(dev));
 
-	if (CONFIG(TPM2)) {
+	if (tlcl_get_family() == TPM_2) {
 		acpigen_write_name_string("_HID", "MSFT0101");
 		acpigen_write_name_string("_CID", "MSFT0101");
 	} else {
diff --git a/src/drivers/tpm/ppi.c b/src/drivers/tpm/ppi.c
index 6f12b411ba..d63b8f811b 100644
--- a/src/drivers/tpm/ppi.c
+++ b/src/drivers/tpm/ppi.c
@@ -5,6 +5,7 @@
 #include <acpi/acpi_device.h>
 #include <cbmem.h>
 #include <console/console.h>
+#include <security/tpm/tss.h>
 
 #include "tpm_ppi.h"
 
@@ -35,6 +36,8 @@ static void set_package_element_name(const char *package_name, unsigned int elem
 /* PPI function is passed in src_op. Converted to Local2. Clobbers Local1 and Local2 */
 static void verify_supported_ppi(uint8_t src_op)
 {
+	enum tpm_family family = tlcl_get_family();
+
 	/*
 	 * Old OSes incorrectly pass a Buffer instead of a Package.
 	 * See TCG Physical Presence Interface Specification Chapter 8.1.2 for details.
@@ -62,7 +65,7 @@ static void verify_supported_ppi(uint8_t src_op)
 	acpigen_write_store();
 	acpigen_emit_namestring("^FSUP");
 	acpigen_emit_byte(LOCAL2_OP);
-	acpigen_emit_byte(CONFIG(TPM1) ? ONE_OP : ZERO_OP);
+	acpigen_emit_byte(family == TPM_1 ? ONE_OP : ZERO_OP);
 	acpigen_emit_byte(LOCAL1_OP);
 	acpigen_write_if_lequal_op_int(LOCAL1_OP, 0);
 
@@ -84,7 +87,7 @@ static void verify_supported_ppi(uint8_t src_op)
 	acpigen_write_store();
 	acpigen_emit_namestring("^FSUP");
 	acpigen_emit_byte(LOCAL2_OP);
-	acpigen_emit_byte(CONFIG(TPM1) ? ZERO_OP : ONE_OP);
+	acpigen_emit_byte(family == TPM_1 ? ZERO_OP : ONE_OP);
 	acpigen_emit_byte(LOCAL1_OP);
 
 	acpigen_write_if_lequal_op_int(LOCAL1_OP, 1);
@@ -114,7 +117,7 @@ static void tpm_ppi_func0_cb(void *arg)
  */
 static void tpm_ppi_func1_cb(void *arg)
 {
-	if (CONFIG(TPM2))
+	if (tlcl_get_family() == TPM_2)
 		/* Interface version: 1.3 */
 		acpigen_write_return_string("1.3");
 	else
@@ -400,6 +403,8 @@ static void tpm_ppi_func7_cb(void *arg)
  */
 static void tpm_ppi_func8_cb(void *arg)
 {
+	enum tpm_family family = tlcl_get_family();
+
 	acpigen_write_to_integer(ARG1_OP, LOCAL0_OP);
 
 	/* Revision 1 */
@@ -410,7 +415,7 @@ static void tpm_ppi_func8_cb(void *arg)
 	acpigen_write_store();
 	acpigen_emit_namestring("^FSUP");
 	acpigen_emit_byte(LOCAL2_OP);
-	acpigen_emit_byte(CONFIG(TPM1) ? ONE_OP : ZERO_OP);
+	acpigen_emit_byte(family == TPM_1 ? ONE_OP : ZERO_OP);
 	acpigen_emit_byte(LOCAL1_OP);
 	acpigen_write_if_lequal_op_int(LOCAL1_OP, 0);
 	acpigen_write_return_byte(0);	/* Not implemented */
@@ -418,7 +423,7 @@ static void tpm_ppi_func8_cb(void *arg)
 
 	// FIXME: Only advertise supported functions
 
-	if (CONFIG(TPM1)) {
+	if (family == TPM_1) {
 		/*
 		 * Some functions do not require PP depending on configuration.
 		 * Those aren't listed here, so the 'required PP' is always set for those.
@@ -434,7 +439,7 @@ static void tpm_ppi_func8_cb(void *arg)
 			acpigen_write_return_integer(PPI8_RET_ALLOWED);
 			acpigen_pop_len();	/* Pop : If */
 		}
-	} else if (CONFIG(TPM2)) {
+	} else if (family == TPM_2) {
 		/*
 		 * Some functions do not require PP depending on configuration.
 		 * Those aren't listed here, so the 'required PP' is always set for those.
@@ -564,6 +569,12 @@ void tpm_ppi_acpi_fill_ssdt(const struct device *dev)
 	printk(BIOS_DEBUG, "PPI: Pending OS request: 0x%x (0x%x)\n", ppib->pprq, ppib->pprm);
 	printk(BIOS_DEBUG, "PPI: OS response: CMD 0x%x = 0x%x\n", ppib->lppr, ppib->pprp);
 
+	enum tpm_family family = tlcl_get_family();
+	if (family == TPM_UNKNOWN) {
+		printk(BIOS_WARN, "PPI: %s: aborting, because no TPM detected\n", __func__);
+		return;
+	}
+
 	/* Clear unsupported fields */
 	ppib->next_step = 0;
 	ppib->ppin = 1; // Not used by ACPI. Read by EDK-2, must be 1.
@@ -574,7 +585,7 @@ void tpm_ppi_acpi_fill_ssdt(const struct device *dev)
 	bool found = false;
 	/* Fill in defaults, the TPM command executor may overwrite this list */
 	memset(ppib->func, 0, sizeof(ppib->func));
-	if (CONFIG(TPM1)) {
+	if (family == TPM_1) {
 		for (size_t i = 0; i < ARRAY_SIZE(tpm1_funcs); i++) {
 			ppib->func[tpm1_funcs[i]] = 1;
 			if (ppib->pprq == tpm1_funcs[i])
@@ -706,17 +717,24 @@ void tpm_ppi_acpi_fill_ssdt(const struct device *dev)
 void lb_tpm_ppi(struct lb_header *header)
 {
 	struct lb_tpm_physical_presence *tpm_ppi;
+	enum tpm_family family;
 	void *ppib;
 
 	ppib = cbmem_find(CBMEM_ID_TPM_PPI);
 	if (!ppib)
 		return;
 
+	family = tlcl_get_family();
+	if (family == TPM_UNKNOWN) {
+		printk(BIOS_WARN, "PPI: %s: aborting, because no TPM detected\n", __func__);
+		return;
+	}
+
 	tpm_ppi = (struct lb_tpm_physical_presence *)lb_new_record(header);
 	tpm_ppi->tag = LB_TAG_TPM_PPI_HANDOFF;
 	tpm_ppi->size = sizeof(*tpm_ppi);
 	tpm_ppi->ppi_address = (uintptr_t)ppib;
-	tpm_ppi->tpm_version = CONFIG(TPM1) ? LB_TPM_VERSION_TPM_VERSION_1_2 :
+	tpm_ppi->tpm_version = family == TPM_1 ? LB_TPM_VERSION_TPM_VERSION_1_2 :
 		LB_TPM_VERSION_TPM_VERSION_2;
 
 	tpm_ppi->ppi_version = BCD(1, 3);
diff --git a/src/security/tpm/tspi/crtm.h b/src/security/tpm/tspi/crtm.h
index 6f5eb2e716..69043e233a 100644
--- a/src/security/tpm/tspi/crtm.h
+++ b/src/security/tpm/tspi/crtm.h
@@ -9,10 +9,8 @@
 #include <types.h>
 #include <vb2_sha.h>
 
-#if CONFIG(TPM_LOG_CB) && CONFIG(TPM1)
-#  define TPM_MEASURE_ALGO VB2_HASH_SHA1
-#elif CONFIG(TPM_LOG_CB) && CONFIG(TPM2)
-#  define TPM_MEASURE_ALGO VB2_HASH_SHA256
+#if CONFIG(TPM_LOG_CB)
+#  define TPM_MEASURE_ALGO (tlcl_get_family() == TPM_1 ? VB2_HASH_SHA1 : VB2_HASH_SHA256)
 #elif CONFIG(TPM_LOG_TPM1)
 #  define TPM_MEASURE_ALGO VB2_HASH_SHA1
 #elif CONFIG(TPM_LOG_TPM2)
diff --git a/src/security/tpm/tspi/tspi.c b/src/security/tpm/tspi/tspi.c
index 1a0f1d5c88..56b8fa8ede 100644
--- a/src/security/tpm/tspi/tspi.c
+++ b/src/security/tpm/tspi/tspi.c
@@ -17,6 +17,9 @@ static tpm_result_t tpm1_invoke_state_machine(void)
 	uint8_t deactivated;
 	tpm_result_t rc = TPM_SUCCESS;
 
+	if (tlcl_get_family() != TPM_1)
+		return rc;
+
 	/* Check that the TPM is enabled and activated. */
 	rc = tlcl1_get_flags(&disabled, &deactivated, NULL);
 	if (rc != TPM_SUCCESS) {
@@ -199,19 +202,19 @@ tpm_result_t tpm_clear_and_reenable(void)
 		return rc;
 	}
 
-#if CONFIG(TPM1)
-	rc = tlcl1_set_enable();
-	if (rc != TPM_SUCCESS) {
-		printk(BIOS_ERR, "TPM Error (%#x): Can't set enabled state.\n", rc);
-		return rc;
-	}
+	if (tlcl_get_family() == TPM_1) {
+		rc = tlcl1_set_enable();
+		if (rc != TPM_SUCCESS) {
+			printk(BIOS_ERR, "TPM Error (%#x): Can't set enabled state.\n", rc);
+			return rc;
+		}
 
-	rc = tlcl1_set_deactivated(0);
-	if (rc != TPM_SUCCESS) {
-		printk(BIOS_ERR, "TPM Error (%#x): Can't set deactivated state.\n", rc);
-		return rc;
+		rc = tlcl1_set_deactivated(0);
+		if (rc != TPM_SUCCESS) {
+			printk(BIOS_ERR, "TPM Error (%#x): Can't set deactivated state.\n", rc);
+			return rc;
+		}
 	}
-#endif
 
 	return TPM_SUCCESS;
 }
diff --git a/src/security/tpm/tss.h b/src/security/tpm/tss.h
index 3a019ead32..c9aec08262 100644
--- a/src/security/tpm/tss.h
+++ b/src/security/tpm/tss.h
@@ -33,16 +33,31 @@
  */
 tpm_result_t tlcl_lib_init(void);
 
-/* Commands */
+/**
+ * Query active TPM family.  Returns TPM_UNKNOWN if uninitialized and TPM_1 or TPM_2 otherwise.
+ */
+static inline enum tpm_family tlcl_get_family(void)
+{
+	/* Defined in tss/tss.c */
+	extern enum tpm_family tlcl_tpm_family;
+
+	if (CONFIG(TPM1) && CONFIG(TPM2))
+		return tlcl_tpm_family;
+	if (CONFIG(TPM1))
+		return TPM_1;
+	if (CONFIG(TPM2))
+		return TPM_2;
+	return TPM_UNKNOWN;
+}
 
-extern enum tpm_family tlcl_tpm_family;
+/* Commands */
 
-#define TLCL_CALL(name, ...) do {                                                \
-		if (CONFIG(TPM1) && (!CONFIG(TPM2) || tlcl_tpm_family == TPM_1)) \
-			return tlcl1_##name(__VA_ARGS__);                        \
-		if (CONFIG(TPM2) && (!CONFIG(TPM1) || tlcl_tpm_family == TPM_2)) \
-			return tlcl2_##name(__VA_ARGS__);                        \
-		return TPM_CB_INTERNAL_INCONSISTENCY;                            \
+#define TLCL_CALL(name, ...) do {                         \
+		if (tlcl_get_family() == TPM_1)           \
+			return tlcl1_##name(__VA_ARGS__); \
+		if (tlcl_get_family() == TPM_2)           \
+			return tlcl2_##name(__VA_ARGS__); \
+		return TPM_CB_INTERNAL_INCONSISTENCY;     \
 	} while (0)
 
 /**
diff --git a/src/security/vboot/secdata_tpm.c b/src/security/vboot/secdata_tpm.c
index 21901bb310..f60a5e2ee0 100644
--- a/src/security/vboot/secdata_tpm.c
+++ b/src/security/vboot/secdata_tpm.c
@@ -30,7 +30,7 @@ static tpm_result_t safe_write(uint32_t index, const void *data, uint32_t length
 
 tpm_result_t antirollback_read_space_kernel(struct vb2_context *ctx)
 {
-	if (!CONFIG(TPM2)) {
+	if (tlcl_get_family() == TPM_1) {
 		/*
 		 * Before reading the kernel space, verify its permissions. If
 		 * the kernel space has the wrong permission, we give up. This
@@ -224,12 +224,6 @@ static uint32_t define_space(const char *name, uint32_t index, uint32_t length,
 	return rc;
 }
 
-/* Nothing special in the TPM2 path yet. */
-static tpm_result_t safe_write(uint32_t index, const void *data, uint32_t length)
-{
-	return tlcl_write(index, data, length);
-}
-
 static tpm_result_t setup_space(const char *name, uint32_t index, const void *data,
 				uint32_t length, const TPMA_NV nv_attributes,
 				const uint8_t *nv_policy, size_t nv_policy_size)
@@ -376,7 +370,7 @@ static tpm_result_t setup_widevine_counter_spaces(void)
 	return rc;
 }
 
-static tpm_result_t _factory_initialize_tpm(struct vb2_context *ctx)
+static tpm_result_t _factory_initialize_tpm2(struct vb2_context *ctx)
 {
 	RETURN_ON_FAILURE(tlcl_force_clear());
 
@@ -426,11 +420,6 @@ static tpm_result_t _factory_initialize_tpm(struct vb2_context *ctx)
 	return TPM_SUCCESS;
 }
 
-tpm_result_t antirollback_lock_space_firmware(void)
-{
-	return tlcl2_lock_nv_write(FIRMWARE_NV_INDEX);
-}
-
 tpm_result_t antirollback_read_space_mrc_hash(uint32_t index, uint8_t *data, uint32_t size)
 {
 	if (size != HASH_NV_SIZE) {
@@ -521,25 +510,9 @@ tpm_result_t antirollback_write_space_vbios_hash(const uint8_t *data, uint32_t s
 	return safe_write(VBIOS_CACHE_NV_INDEX, data, size);
 }
 
-#else
+#endif /* CONFIG(TPM2) */
 
-/**
- * Like tlcl_write(), but checks for write errors due to hitting the 64-write
- * limit and clears the TPM when that happens.  This can only happen when the
- * TPM is unowned, so it is OK to clear it (and we really have no choice).
- * This is not expected to happen frequently, but it could happen.
- */
-
-static tpm_result_t safe_write(uint32_t index, const void *data, uint32_t length)
-{
-	tpm_result_t rc = tlcl_write(index, data, length);
-	if (rc == TPM_MAXNVWRITES) {
-		RETURN_ON_FAILURE(tpm_clear_and_reenable());
-		return tlcl_write(index, data, length);
-	} else {
-		return rc;
-	}
-}
+#if CONFIG(TPM1)
 
 /**
  * Similarly to safe_write(), this ensures we don't fail a DefineSpace because
@@ -558,7 +531,7 @@ static tpm_result_t safe_define_space(uint32_t index, uint32_t perm, uint32_t si
 	}
 }
 
-static tpm_result_t _factory_initialize_tpm(struct vb2_context *ctx)
+static tpm_result_t _factory_initialize_tpm1(struct vb2_context *ctx)
 {
 	TPM_PERMANENT_FLAGS pflags;
 	tpm_result_t rc;
@@ -616,12 +589,45 @@ static tpm_result_t _factory_initialize_tpm(struct vb2_context *ctx)
 	return TPM_SUCCESS;
 }
 
-tpm_result_t antirollback_lock_space_firmware(void)
+#endif /* CONFIG(TPM1) */
+
+static tpm_result_t safe_write(uint32_t index, const void *data, uint32_t length)
 {
-	return tlcl1_set_global_lock();
+	tpm_result_t rc = tlcl_write(index, data, length);
+	if (tlcl_get_family() == TPM_1 && rc == TPM_MAXNVWRITES) {
+		/**
+		 * Clear the TPM on write error due to hitting the 64-write
+		 * limit.  This can only happen when the TPM is unowned, so it
+		 * is OK to clear it (and we really have no choice).  This is
+		 * not expected to happen frequently, but it could happen.
+		 */
+		RETURN_ON_FAILURE(tpm_clear_and_reenable());
+		rc = tlcl_write(index, data, length);
+	}
+	return rc;
 }
 
+static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
+{
+#if CONFIG(TPM1)
+	if (tlcl_get_family() == TPM_1)
+		return _factory_initialize_tpm1(ctx);
+#endif
+#if CONFIG(TPM2)
+	if (tlcl_get_family() == TPM_2)
+		return _factory_initialize_tpm2(ctx);
 #endif
+	return TPM_CB_CORRUPTED_STATE;
+}
+
+uint32_t antirollback_lock_space_firmware(void)
+{
+	if (tlcl_get_family() == TPM_1)
+		return tlcl1_set_global_lock();
+	if (tlcl_get_family() == TPM_2)
+		return tlcl2_lock_nv_write(FIRMWARE_NV_INDEX);
+	return TPM_CB_CORRUPTED_STATE;
+}
 
 /**
  * Perform one-time initializations.
diff --git a/src/security/vboot/tpm_common.c b/src/security/vboot/tpm_common.c
index 997c4e9cd9..dedf8dfebc 100644
--- a/src/security/vboot/tpm_common.c
+++ b/src/security/vboot/tpm_common.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <security/tpm/tspi.h>
+#include <security/tpm/tss.h>
 #include <security/vboot/tpm_common.h>
 #include <security/tpm/tss_errors.h>
 #include <vb2_api.h>
@@ -43,7 +44,8 @@ tpm_result_t vboot_extend_pcr(struct vb2_context *ctx, int pcr,
 	 */
 	_Static_assert(sizeof(buffer) >= VB2_SHA256_DIGEST_SIZE,
 		       "Buffer needs to be able to fit at least a SHA256");
-	enum vb2_hash_algorithm algo = CONFIG(TPM1) ? VB2_HASH_SHA1 : VB2_HASH_SHA256;
+	enum vb2_hash_algorithm algo = tlcl_get_family() == TPM_1 ?
+		VB2_HASH_SHA1 : VB2_HASH_SHA256;
 
 	switch (which_digest) {
 	/* SHA1 of (devmode|recmode|keyblock) bits */
diff --git a/src/vendorcode/google/chromeos/cse_board_reset.c b/src/vendorcode/google/chromeos/cse_board_reset.c
index e7cb878b68..f3369483e3 100644
--- a/src/vendorcode/google/chromeos/cse_board_reset.c
+++ b/src/vendorcode/google/chromeos/cse_board_reset.c
@@ -19,6 +19,11 @@ void cse_board_reset(void)
 	if (CONFIG(CSE_RESET_CLEAR_EC_AP_IDLE_FLAG))
 		google_chromeec_clear_ec_ap_idle();
 
+	/*
+	 * Assuming that if particular TPM implementation is enabled at compile
+	 * time, it's the one being used.  This isn't generic code, so can
+	 * probably get away with it.
+	 */
 	if (CONFIG(TPM2) && CONFIG(TPM_GOOGLE_CR50)) {
 		/* Initialize TPM and get the cr50 firmware version. */
 		rc = tlcl_lib_init();
diff --git a/src/vendorcode/google/chromeos/tpm2.c b/src/vendorcode/google/chromeos/tpm2.c
index 31c28c9d2a..8823978de4 100644
--- a/src/vendorcode/google/chromeos/tpm2.c
+++ b/src/vendorcode/google/chromeos/tpm2.c
@@ -22,6 +22,10 @@ static void disable_platform_hierarchy(void *unused)
 		return;
 	}
 
+	/* In case both families are enabled, but TPM1 is in use. */
+	if (tlcl_get_family() != TPM_2)
+		return;
+
 	rc = tlcl2_disable_platform_hierarchy();
 	if (rc != TPM_SUCCESS)
 		printk(BIOS_ERR, "Platform hierarchy disablement failed: %#x\n",