drivers/i2c/tpm: use iobuf library for marshaling commands

Use the iobuf API instead of relying on own buffer management. It
also provides consistency between marshaling and unmarshaling code
paths for propagating return values instead of overloading the values
of existing variables.

BUG=b:36598499

Change-Id: Iec0bbff1312e8e6ec616d1528db8667f32e682c9
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/19063
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/src/lib/tpm2_marshaling.h b/src/lib/tpm2_marshaling.h
index e177d0609a..5802044378 100644
--- a/src/lib/tpm2_marshaling.h
+++ b/src/lib/tpm2_marshaling.h
@@ -6,6 +6,7 @@
 #ifndef __SRC_LIB_TPM2_MARSHALING_H
 #define __SRC_LIB_TPM2_MARSHALING_H
 
+#include <commonlib/iobuf.h>
 #include "tpm2_tlcl_structures.h"
 
 /* The below functions are used to serialize/deserialize TPM2 commands. */
@@ -18,14 +19,13 @@
  *
  * @command: code of the TPM2 command to marshal
  * @tpm_command_body: a pointer to the command specific structure
- * @buffer: buffer where command is marshaled to
- * @buffer_size: size of the buffer
+ * @ob: output buffer where command is marshaled to
  *
- * Returns number of bytes placed in the buffer, or -1 on error.
+ * Returns 0 on success or -1 on error.
  *
  */
 int tpm_marshal_command(TPM_CC command, void *tpm_command_body,
-			void *buffer, size_t buffer_size);
+			struct obuf *ob);
 
 /**
  * tpm_unmarshal_response
@@ -36,14 +36,11 @@ int tpm_marshal_command(TPM_CC command, void *tpm_command_body,
  * struct tpm2_response is a union of all possible responses.
  *
  * @command: code of the TPM2 command for which a response is unmarshaled
- * @response_body: buffer containing the serialized response.
- * @response_size: number of bytes in the buffer containing response
+ * @ib: input buffer containing the serialized response.
  *
  * Returns a pointer to the deserialized response or NULL in case of
  * unmarshaling problems.
  */
-struct tpm2_response *tpm_unmarshal_response(TPM_CC command,
-					     void *response_body,
-					     size_t response_size);
+struct tpm2_response *tpm_unmarshal_response(TPM_CC command, struct ibuf *ib);
 
 #endif // __SRC_LIB_TPM2_MARSHALING_H