tpm: let the caller of TPM reset decide if the EC needs to be reset too

TPM reset sequence when TPM wipeout is requested has a side effect of
rebooting the entire device. This is not always desirable, in some
cases other actions need to happen before the device is rebooted.

This patch makes resetting the EC the TPM reset caller's responsibility,

BRANCH=cr50
BUG=none
TEST=verified that RMA reset and WP disable properly wipe out the TPM
      and reboot the device.

Change-Id: I6e827ce923a2454ae5b2e2597d1a4c9390bbb8b6
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/733813
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>
(cherry picked from commit e3d15afa68d9e4c8866a0301b33ff6e6d78b1750)
Reviewed-on: https://chromium-review.googlesource.com/736814

1 files changed, 2 insertions, 2 deletions

diff --git a/include/tpm_registers.h b/include/tpm_registers.h
index 38cb68ef9e..cf7fbe5758 100644
--- a/include/tpm_registers.h
+++ b/include/tpm_registers.h
@@ -37,8 +37,8 @@ void tpm_register_interface(interface_restart_func interface_restart);
  * returns EC_SUCCESS after the reset has completed, or an error code on
  * failure.
  *
- * If wipe_nvmem_first is true, the EC and AP will be forced off and TPM memory
- * will be erased before the TPM task is reset.
+ * If wipe_nvmem_first is true, the caller is expected to keep the rest of the
+ * system in reset until TPM wipeout is completed.
  */
 int tpm_reset_request(int wait_until_done, int wipe_nvmem_first);