cr50: tpm: ignore sys_rst_l/plt_rst_l when TPM reset is in progress

There is no point in invoking TPM reset while the current invocation
is in progress. One of the cases when this is happening is early start
up on Kevin/Gru: the device starts booting, the EC comes around to
pulsing sys_rst_l when TPM is already busy installing endorsement
certificates.

There is no point in issuing another reset at that point, just let the
process continue.

BRANCH=none
BUG=chrome-os-partner:52366
TEST=firmware_TPMKernelVersion firmware_TPMExtend autotests still pass
     on kevin. Certificate installation during startup does not get
     interrupted any more.

Change-Id: Ibdface9f7a76186e210ef0f4111cd5fe9905bba9
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/389811
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/tpm_registers.h b/include/tpm_registers.h
index 9c9390ffb7..dfdfefdc34 100644
--- a/include/tpm_registers.h
+++ b/include/tpm_registers.h
@@ -42,6 +42,13 @@ void tpm_register_interface(interface_restart_func interface_restart);
 int tpm_reset(void);
 
 /*
+ * Return true if tpm is being reset. Usually this helps to avoid unnecessary
+ * extra reset early at startup time, when TPM could be busy installing
+ * endorsement certificates.
+ */
+int tpm_is_resetting(void);
+
+/*
  * This structure describes the header of all commands and responses sent and
  * received over TPM FIFO.
  *