security/tpm/: turn tis_{init,open} into tis_probe

init() was always followed by open() and after successful initialization
we only need send-receive function which is now returned by tis_probe()
on success, thus further reducing number of functions to export from
drivers.

This also removes check for opening TIS twice that seems to have no
value.

Change-Id: I52ad8d69d50d449f031c36b15bf70ef07986946c
Ticket: https://ticket.coreboot.org/issues/433
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76954
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 47 insertions, 55 deletions

diff --git a/src/security/tpm/tis.h b/src/security/tpm/tis.h
index 34dc8e8bd7..ac07bfb5c6 100644
--- a/src/security/tpm/tis.h
+++ b/src/security/tpm/tis.h
@@ -33,23 +33,6 @@ enum tis_status {
 };
 
 /*
- * tis_init()
- *
- * Initialize the TPM device.
- * Returns TSS Return Code from TCG TPM Structures.  See tss_errors.h
- */
-tpm_result_t tis_init(void);
-
-/*
- * tis_open()
- *
- * Requests access to locality 0 for the caller.
- *
- * Returns TSS Return Code from TCG TPM Structures.  See tss_errors.h
- */
-tpm_result_t tis_open(void);
-
-/*
  * tis_sendrecv()
  *
  * Send the requested data to the TPM and then try to get its response
@@ -61,8 +44,19 @@ tpm_result_t tis_open(void);
  *
  * Returns TSS Return Code from TCG TPM Structures.  See tss_errors.h
  */
-tpm_result_t tis_sendrecv(const u8 *sendbuf, size_t send_size, u8 *recvbuf,
-			size_t *recv_len);
+typedef tpm_result_t (*tis_sendrecv_fn)(const u8 *sendbuf, size_t send_size, u8 *recvbuf,
+					size_t *recv_len);
+
+/*
+ * tis_probe()
+ *
+ * Probe for the TPM device and set it up for use within locality 0. Returns
+ * pointer to send-receive function on success or NULL on failure.
+ *
+ * Do not call this explicitly, it's meant to be used exclusively by TSS
+ * implementation (tlcl_lib_init() function to be specific).
+ */
+tis_sendrecv_fn tis_probe(void);
 
 /*
  * tis_vendor_write()
diff --git a/src/security/tpm/tss/tcg-1.2/tss.c b/src/security/tpm/tss/tcg-1.2/tss.c
index e73db388e8..f0d28dfe3f 100644
--- a/src/security/tpm/tss/tcg-1.2/tss.c
+++ b/src/security/tpm/tss/tcg-1.2/tss.c
@@ -24,13 +24,22 @@
 #include <console/console.h>
 #define VBDEBUG(format, args...) printk(BIOS_DEBUG, format, ## args)
 
+static tis_sendrecv_fn tis_sendrecv;
+
 static tpm_result_t tpm_send_receive(const uint8_t *request,
-				uint32_t request_length,
-				uint8_t *response,
-				uint32_t *response_length)
+				     uint32_t request_length,
+				     uint8_t *response,
+				     uint32_t *response_length)
 {
 	size_t len = *response_length;
-	tpm_result_t rc = tis_sendrecv(request, request_length, response, &len);
+	tpm_result_t rc;
+
+	if (tis_sendrecv == NULL) {
+		printk(BIOS_ERR, "Attempted use of uninitialized TSS 1.2 stack\n");
+		return TPM_FAIL;
+	}
+
+	rc = tis_sendrecv(request, request_length, response, &len);
 	if (rc)
 		return rc;
 	/* check 64->32bit overflow and (re)check response buffer overflow */
@@ -142,23 +151,16 @@ static tpm_result_t send(const uint8_t *command)
 
 /* Exported functions. */
 
-static uint8_t tlcl_init_done;
-
 tpm_result_t tlcl_lib_init(void)
 {
-	tpm_result_t rc = TPM_SUCCESS;
-	if (tlcl_init_done)
-		return rc;
-	rc = tis_init();
-	if (rc)
-		return rc;
-	rc = tis_open();
-	if (rc)
-		return rc;
+	if (tis_sendrecv != NULL)
+		return TPM_SUCCESS;
 
-	tlcl_init_done = 1;
+	tis_sendrecv = tis_probe();
+	if (tis_sendrecv == NULL)
+		return TPM_CB_NO_DEVICE;
 
-	return rc;
+	return TPM_SUCCESS;
 }
 
 tpm_result_t tlcl_startup(void)
diff --git a/src/security/tpm/tss/tcg-2.0/tss.c b/src/security/tpm/tss/tcg-2.0/tss.c
index e23a0d280d..135d2964e6 100644
--- a/src/security/tpm/tss/tcg-2.0/tss.c
+++ b/src/security/tpm/tss/tcg-2.0/tss.c
@@ -16,6 +16,8 @@
  * TPM2 specification.
  */
 
+static tis_sendrecv_fn tis_sendrecv;
+
 void *tpm_process_command(TPM_CC command, void *command_body)
 {
 	struct obuf ob;
@@ -26,6 +28,11 @@ void *tpm_process_command(TPM_CC command, void *command_body)
 	/* Command/response buffer. */
 	static uint8_t cr_buffer[TPM_BUFFER_SIZE];
 
+	if (tis_sendrecv == NULL) {
+		printk(BIOS_ERR, "Attempted use of uninitialized TSS 2.0 stack\n");
+		return NULL;
+	}
+
 	obuf_init(&ob, cr_buffer, sizeof(cr_buffer));
 
 	if (tpm_marshal_command(command, command_body, &ob) < 0) {
@@ -201,30 +208,19 @@ tpm_result_t tlcl_clear_control(bool disable)
 	return TPM_SUCCESS;
 }
 
-static uint8_t tlcl_init_done;
-
 /* This function is called directly by vboot, uses vboot return types. */
 tpm_result_t tlcl_lib_init(void)
 {
-	tpm_result_t rc = TPM_SUCCESS;
-	if (tlcl_init_done)
-		return rc;
-
-	rc = tis_init();
-	if (rc) {
-		printk(BIOS_ERR, "%s: tis_init returned error %d\n", __func__, rc);
-		return rc;
-	}
-	rc = tis_open();
-	if (rc) {
-		printk(BIOS_ERR, "%s: tis_open returned error %d\n"
-			, __func__, rc);
-		return rc;
-	}
+	if (tis_sendrecv != NULL)
+		return TPM_SUCCESS;
 
-	tlcl_init_done = 1;
+	tis_sendrecv = tis_probe();
+	if (tis_sendrecv == NULL) {
+		printk(BIOS_ERR, "%s: tis_probe returned error\n", __func__);
+		return TPM_CB_NO_DEVICE;
+	}
 
-	return rc;
+	return TPM_SUCCESS;
 }
 
 tpm_result_t tlcl_physical_presence_cmd_enable(void)