cr50: pass essential ccd commands through tpm task context

Using and extending the existing framework, move ccd commands
'password, lock, open, and unlock to the same processing path.

The first three commands accept a single parameter, password. It is
required for the password command and optional for unlock and open.
The lock command does not require any parameters.

Wiping the TPM, if necessary, now happens on the same context where
CCD command is executed, i.e. the TPM task context. This is why the
same context TPM reset function needs to be exported and used here.

ccd_open() and ccd_unlock() could be further refactored, this would
require a bit more effort to find appropriate balance between
commonalities and differences.

BRANCH=cr50
BUG=b:62537474
TEST=verified that ccd commands to open, unlock, lock and set and
      clear password all work.

Change-Id: I2b9f2b550347b590a55bfaef262a4f050d3f4c1c
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/854709
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/tpm_registers.h b/include/tpm_registers.h
index 5da9ab6c2f..b82a355170 100644
--- a/include/tpm_registers.h
+++ b/include/tpm_registers.h
@@ -55,6 +55,12 @@ int tpm_reset_request(int wait_until_done, int wipe_nvmem_first);
 void tpm_reinstate_nvmem_commits(void);
 
 /*
+ * To be called by functions running on the TPM task context. Returns
+ * EC_SUCCESS on successful reset.
+ */
+int tpm_sync_reset(int wipe_first);
+
+/*
  * This structure describes the header of all commands and responses sent and
  * received over TPM FIFO.
  *