tcti-helper: Properly handle state transition from init to ready

If the TPM does not automatically transition from init -> idle -> ready, manually trigger the transition by writing 1 to commandReady. Signed-off-by: wenxin.leong <wenxin.leong@infineon.com>
tpm2-software · Sep 8, 2023 · 41f58ba · 41f58ba
1 parent b7bad34
commit 41f58ba
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Showing 2 changed files with 28 additions and 6 deletions.
diff --git a/src/tss2-tcti/tcti-i2c-helper.c b/src/tss2-tcti/tcti-i2c-helper.c
@@ -42,6 +42,8 @@
 #define LOGMODULE tcti
 #include "util/log.h"
 
+#define TIMEOUT_B 2000 /* The default timeout value as specified in the TCG spec. */
+
 /*
  * CRC-CCITT KERMIT with following parameters:
  *
@@ -560,7 +562,7 @@ TSS2_RC tcti_i2c_helper_transmit (TSS2_TCTI_CONTEXT *tcti_ctx, size_t size, cons
 
     /* Wait until ready bit is set by TPM device */
     uint32_t expected_status_bits = TCTI_I2C_HELPER_TPM_STS_COMMAND_READY;
-    rc = i2c_tpm_helper_wait_for_status (ctx, expected_status_bits, expected_status_bits, 200);
+    rc = i2c_tpm_helper_wait_for_status (ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
     if (rc != TSS2_RC_SUCCESS) {
         LOG_ERROR("Failed waiting for TPM to become ready");
         return rc;
@@ -817,14 +819,23 @@ TSS2_RC Tss2_Tcti_I2c_Helper_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size
         return TSS2_TCTI_RC_IO_ERROR;
     }
 
-    /* Wait up to 200ms for TPM to become ready */
+    /* Wait up to TIMEOUT_B for TPM to become ready */
     LOG_DEBUG ("Waiting for TPM to become ready...");
     uint32_t expected_status_bits = TCTI_I2C_HELPER_TPM_STS_COMMAND_READY;
-    rc = i2c_tpm_helper_wait_for_status (ctx, expected_status_bits, expected_status_bits, 200);
+    rc = i2c_tpm_helper_wait_for_status (ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
+    if (rc == TSS2_TCTI_RC_TRY_AGAIN) {
+        /*
+         * TPM did not auto transition into ready state,
+         * write 1 to commandReady to start the transition.
+         */
+        i2c_tpm_helper_write_sts_reg (ctx, TCTI_I2C_HELPER_TPM_STS_COMMAND_READY);
+        rc = i2c_tpm_helper_wait_for_status (ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
+    }
     if (rc != TSS2_RC_SUCCESS) {
         LOG_ERROR ("Failed waiting for TPM to become ready");
         return rc;
     }
+
     LOG_DEBUG ("TPM is ready");
 
     /* Get rid */

diff --git a/src/tss2-tcti/tcti-spi-helper.c b/src/tss2-tcti/tcti-spi-helper.c
@@ -22,6 +22,8 @@
 #define LOGMODULE tcti
 #include "util/log.h"
 
+#define TIMEOUT_B 2000 // The default timeout value as specified in the TCG spec
+
 static inline TSS2_RC spi_tpm_helper_delay_ms(TSS2_TCTI_SPI_HELPER_CONTEXT* ctx, int milliseconds)
 {
     // Sleep a specified amount of milliseconds
@@ -621,7 +623,7 @@ TSS2_RC tcti_spi_helper_transmit (TSS2_TCTI_CONTEXT *tcti_ctx, size_t size, cons
 
     // Wait until ready bit is set by TPM device
     uint32_t expected_status_bits = TCTI_SPI_HELPER_TPM_STS_COMMAND_READY;
-    rc = spi_tpm_helper_wait_for_status(ctx, expected_status_bits, expected_status_bits, 200);
+    rc = spi_tpm_helper_wait_for_status(ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
     if (rc != TSS2_RC_SUCCESS) {
         LOG_ERROR("Failed waiting for TPM to become ready");
         return rc;
@@ -736,14 +738,23 @@ TSS2_RC Tss2_Tcti_Spi_Helper_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size
         return TSS2_TCTI_RC_IO_ERROR;
     }
 
-    // Wait up to 200ms for TPM to become ready
+    // Wait up to TIMEOUT_B for TPM to become ready
     LOG_DEBUG("Waiting for TPM to become ready...");
     uint32_t expected_status_bits = TCTI_SPI_HELPER_TPM_STS_COMMAND_READY;
-    rc = spi_tpm_helper_wait_for_status(ctx, expected_status_bits, expected_status_bits, 200);
+    rc = spi_tpm_helper_wait_for_status(ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
+    if (rc == TSS2_TCTI_RC_TRY_AGAIN) {
+        /*
+         * TPM did not auto transition into ready state,
+         * write 1 to commandReady to start the transition.
+         */
+        spi_tpm_helper_write_sts_reg(ctx, TCTI_SPI_HELPER_TPM_STS_COMMAND_READY);
+        rc = spi_tpm_helper_wait_for_status(ctx, expected_status_bits, expected_status_bits, TIMEOUT_B);
+    }
     if (rc != TSS2_RC_SUCCESS) {
         LOG_ERROR("Failed waiting for TPM to become ready");
         return rc;
     }
+
     LOG_DEBUG("TPM is ready");
 
     // Get rid