Move ContinueSelfTest to a later point to save time.

firmware/lib/tpm_lite/tlcl.c

Index: firmware/lib/tpm_lite/tlcl.c
diff --git a/firmware/lib/tpm_lite/tlcl.c b/firmware/lib/tpm_lite/tlcl.c
index 6252700d81dd092c781fe8912f86a82a16a1116c..249922e61c767979f49998114bba903a31278eb2 100644
--- a/firmware/lib/tpm_lite/tlcl.c
+++ b/firmware/lib/tpm_lite/tlcl.c
@@ -44,11 +44,11 @@ static INLINE int TpmReturnCode(const uint8_t* buffer) {
   return TpmCommandCode(buffer);
 }
 
-/* Sends a TPM command and gets a response.  Returns 0 if success or the TPM
- * error code if error. */
-static uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
-                                int max_length) {
-
+/* Like TlclSendReceive below, but do not retry if NEEDS_SELFTEST or
+ * DOING_SELFTEST errors are returned.
+ */
+static uint32_t TlclSendReceiveNoRetry(const uint8_t* request,
+                                       uint8_t* response, int max_length) {
   uint32_t result;
 
 #ifdef EXTRA_LOGGING
@@ -83,6 +83,31 @@ static uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
 }
 
 
+/* Sends a TPM command and gets a response.  Returns 0 if success or the TPM
+ * error code if error. Waits for self test to complete if needed. */
+static uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
+                                int max_length) {
+  uint32_t result = TlclSendReceiveNoRetry(request, response, max_length);
+  if (result == TPM_E_NEEDS_SELFTEST || result == TPM_E_DOING_SELFTEST) {
+    result = TlclContinueSelfTest();
+    if (result != TPM_SUCCESS) {
+      return result;
+    }
+#ifdef TPM_BLOCKING_CONTINUESELFTEST
+    result = TlclSendReceiveNoRetry(request, response, max_length);
+#else
+    /* This needs serious testing.  The TPM specification says: iii. The caller
+     * MUST wait for the actions of TPM_ContinueSelfTest to complete before
+     * reissuing the command C1.  But, how do we know that the actions have
+     * completed other than trying again? */
+    do {
+      result = TlclSendReceiveNoRetry(request, response, max_length);
+    } while (result == TPM_E_DOING_SELFTEST);

[Randall Spangler, 2011/03/16 19:23:06]

If the TPM gets in a wonky state, this could block forever and brick the system.
 I'd rather have the command fail and throw us into recovery mode than lock up.

One way to handle that would be to pass an allow_retries flag down through
everything (because sigh, no global variables), and then turn that off if the
recovery button is pressed.

[Luigi Semenzato, 2011/03/16 20:51:59]

Ah, now I remember, that's why we wanted the compilation-time flag.

+#endif
+  }
+  return result;
+}
+
 /* Sends a command and returns the error code. */
 static uint32_t Send(const uint8_t* command) {
   uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
@@ -116,8 +141,11 @@ uint32_t TlclSelfTestFull(void) {
 }
 
 uint32_t TlclContinueSelfTest(void) {
+  uint8_t response[TPM_LARGE_ENOUGH_COMMAND_SIZE];
   VBDEBUG(("TPM: Continue self test\n"));
-  return Send(tpm_continueselftest_cmd.buffer);
+  /* Call the No Retry version of SendReceive to avoid recursion. */
+  return TlclSendReceiveNoRetry(tpm_continueselftest_cmd.buffer,
+                                response, sizeof(response));
 }
 
 uint32_t TlclDefineSpace(uint32_t index, uint32_t perm, uint32_t size) {