tpm: reset communications channels when resetting TPM

TPM resets happen asynchronously, conceivably there is some interface
(i2cs or sps) activity under way when TPM is reset.

Sps driver provides a means of disconnecting the client of the driver,
while the i2cs driver does not. Come to think of it, there is no real
need to provide a special function to disconnect a client, this makes
API simpler and allows to add driver initialization to the client
registration function.

To make tpm_registers.c more flexible - allow to register a callback
for interface initialization, this way when TPM is reset, the
interface can be also re-initialized and is guaranteed to start from
scratch after reset.

BRANCH=none
BUG=chrome-os-partner:52366
TEST=both firmware_TPMExtend and firmware_TPMKernelVersion autotests
     pass

Change-Id: I212166a23f9cd512d8f75315377d1f5620aea070
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/388886
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/common/i2cs_tpm.c b/common/i2cs_tpm.c
index 7700fd8373..5aa3a07e01 100644
--- a/common/i2cs_tpm.c
+++ b/common/i2cs_tpm.c
@@ -223,8 +223,16 @@ static void wr_complete_handler(void *i2cs_data, size_t i2cs_data_size)
 	gpio_set_level(GPIO_INT_AP_L, 1);
 }
 
-static void i2cs_tpm_init(void)
+static void i2cs_tpm_enable(void)
 {
 	i2cs_register_write_complete_handler(wr_complete_handler);
 }
-DECLARE_HOOK(HOOK_INIT, i2cs_tpm_init, HOOK_PRIO_LAST);
+
+static void i2cs_if_register(void)
+{
+	if (!(system_get_board_properties() & BOARD_SLAVE_CONFIG_I2C))
+		return;
+
+	tpm_register_interface(i2cs_tpm_enable);
+}
+DECLARE_HOOK(HOOK_INIT, i2cs_if_register, HOOK_PRIO_LAST);