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>

1 files changed, 13 insertions, 21 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. */