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

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

Change-Id: Ib4ce35ada24e3959ea1a518c29d431b4ae123809
Ticket: https://ticket.coreboot.org/issues/433
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68991
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 31 insertions, 41 deletions

diff --git a/src/security/tpm/tis.h b/src/security/tpm/tis.h
index 04a137f12e..b6a258f491 100644
--- a/src/security/tpm/tis.h
+++ b/src/security/tpm/tis.h
@@ -34,25 +34,6 @@ enum tis_status {
 };
 
 /*
- * tis_init()
- *
- * Initialize the TPM device. Returns 0 on success or -1 on
- * failure (in case device probing did not succeed).
- */
-int tis_init(void);
-
-/*
- * tis_open()
- *
- * Requests access to locality 0 for the caller.
- *
- * Returns 0 on success, -1 on failure.
- */
-int tis_open(void);
-
-/*
- * tis_sendrecv()
- *
  * Send the requested data to the TPM and then try to get its response
  *
  * @sendbuf - buffer of the data to send
@@ -63,8 +44,19 @@ int tis_open(void);
  * Returns 0 on success (and places the number of response bytes at recv_len)
  * or -1 on failure.
  */
-int tis_sendrecv(const u8 *sendbuf, size_t send_size, u8 *recvbuf,
-			size_t *recv_len);
+typedef int (*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);
 
 /* TODO: This is supposed to be used only for Google TPM.
    Consider moving this to drivers/tpm/cr50.h. */
diff --git a/src/security/tpm/tss/tcg-1.2/tss.c b/src/security/tpm/tss/tcg-1.2/tss.c
index 39c44eca9f..7f0607ba82 100644
--- a/src/security/tpm/tss/tcg-1.2/tss.c
+++ b/src/security/tpm/tss/tcg-1.2/tss.c
@@ -24,12 +24,18 @@
 #include <console/console.h>
 #define VBDEBUG(format, args...) printk(BIOS_DEBUG, format, ## args)
 
+static tis_sendrecv_fn tis_sendrecv;
+
 static int tpm_send_receive(const uint8_t *request,
 				uint32_t request_length,
 				uint8_t *response,
 				uint32_t *response_length)
 {
 	size_t len = *response_length;
+
+	if (tis_sendrecv == NULL)
+		die("TSS 1.2 wasn't initialized\n");
+
 	if (tis_sendrecv(request, request_length, response, &len))
 		return VB2_ERROR_UNKNOWN;
 	/* check 64->32bit overflow and (re)check response buffer overflow */
@@ -140,20 +146,15 @@ static uint32_t send(const uint8_t *command)
 
 /* Exported functions. */
 
-static uint8_t tlcl_init_done;
-
 uint32_t tlcl_lib_init(void)
 {
-	if (tlcl_init_done)
+	if (tis_sendrecv != NULL)
 		return VB2_SUCCESS;
 
-	if (tis_init())
-		return VB2_ERROR_UNKNOWN;
-	if (tis_open())
+	tis_sendrecv = tis_probe();
+	if (tis_sendrecv == NULL)
 		return VB2_ERROR_UNKNOWN;
 
-	tlcl_init_done = 1;
-
 	return VB2_SUCCESS;
 }
 
diff --git a/src/security/tpm/tss/tcg-2.0/tss.c b/src/security/tpm/tss/tcg-2.0/tss.c
index d228c7f6a8..a787b13fa1 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 +28,9 @@ 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)
+		die("TSS 2.0 wasn't initialized\n");
+
 	obuf_init(&ob, cr_buffer, sizeof(cr_buffer));
 
 	if (tpm_marshal_command(command, command_body, &ob) < 0) {
@@ -201,26 +206,18 @@ uint32_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. */
 uint32_t tlcl_lib_init(void)
 {
-	if (tlcl_init_done)
+	if (tis_sendrecv != NULL)
 		return VB2_SUCCESS;
 
-	if (tis_init()) {
-		printk(BIOS_ERR, "%s: tis_init returned error\n", __func__);
+	tis_sendrecv = tis_probe();
+	if (tis_sendrecv == NULL) {
+		printk(BIOS_ERR, "%s: tis_probe returned error\n", __func__);
 		return VB2_ERROR_UNKNOWN;
 	}
 
-	if (tis_open()) {
-		printk(BIOS_ERR, "%s: tis_open returned error\n", __func__);
-		return VB2_ERROR_UNKNOWN;
-	}
-
-	tlcl_init_done = 1;
-
 	return VB2_SUCCESS;
 }