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>

1 files changed, 13 insertions, 26 deletions

diff --git a/src/drivers/spi/tpm/tis.c b/src/drivers/spi/tpm/tis.c
index 6fa6c828483c..90d7f59ba991 100644
--- a/src/drivers/spi/tpm/tis.c
+++ b/src/drivers/spi/tpm/tis.c
@@ -5,8 +5,6 @@
 
 #include "tpm.h"
 
-static unsigned int tpm_is_open;
-
 static const struct {
 	uint16_t vid;
 	uint16_t did;
@@ -29,31 +27,33 @@ static const char *tis_get_dev_name(struct tpm2_info *info)
 	return "Unknown";
 }
 
-tpm_result_t tis_open(void)
+static tpm_result_t tpm_sendrecv(const uint8_t *sendbuf, size_t sbuf_size,
+				 uint8_t *recvbuf, size_t *rbuf_len)
 {
-	if (tpm_is_open) {
-		printk(BIOS_ERR, "%s() called twice.\n", __func__);
+	int len = tpm2_process_command(sendbuf, sbuf_size, recvbuf, *rbuf_len);
+
+	if (len == 0)
 		return TPM_CB_FAIL;
-	}
+
+	*rbuf_len = len;
+
 	return TPM_SUCCESS;
 }
 
-tpm_result_t tis_init(void)
+tis_sendrecv_fn tis_probe(void)
 {
 	struct spi_slave spi;
 	struct tpm2_info info;
-	tpm_result_t rc = TPM_SUCCESS;
 
 	if (spi_setup_slave(CONFIG_DRIVER_TPM_SPI_BUS,
 			    CONFIG_DRIVER_TPM_SPI_CHIP, &spi)) {
 		printk(BIOS_ERR, "Failed to setup TPM SPI slave\n");
-		return TPM_CB_FAIL;
+		return NULL;
 	}
 
-	rc = tpm2_init(&spi);
-	if (rc) {
+	if (tpm2_init(&spi)) {
 		printk(BIOS_ERR, "Failed to initialize TPM SPI interface\n");
-		return rc;
+		return NULL;
 	}
 
 	tpm2_get_info(&info);
@@ -61,18 +61,5 @@ tpm_result_t tis_init(void)
 	printk(BIOS_INFO, "Initialized TPM device %s revision %d\n",
 	       tis_get_dev_name(&info), info.revision);
 
-	return TPM_SUCCESS;
-}
-
-tpm_result_t tis_sendrecv(const uint8_t *sendbuf, size_t sbuf_size,
-		 uint8_t *recvbuf, size_t *rbuf_len)
-{
-	int len = tpm2_process_command(sendbuf, sbuf_size, recvbuf, *rbuf_len);
-
-	if (len == 0)
-		return TPM_CB_FAIL;
-
-	*rbuf_len = len;
-
-	return TPM_SUCCESS;
+	return &tpm_sendrecv;
 }