tpm: add a function that performs selftest + startup
As described in [0] if a command requires use of an untested algorithm
or functional module, the TPM performs the test and then completes the
command actions.
Since we don't check for TPM_RC_NEEDS_TEST (which is the return code of
the TPM in that case) and even if we would, it would complicate our TPM
code for no apparent reason, add a wrapper function that performs both
the selftest and the startup sequence of the TPM.
It's worth noting that this is implemented on TPMv2.0. The code for
1.2 would look similar, but I don't have a device available to test.
[0]
https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-1-Architecture-01.07-2014-03-13.pdf
ยง12.3 Self-test modes
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index 2df3dad..2b6980e 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -690,4 +690,20 @@
u32 tpm2_enable_nvcommits(struct udevice *dev, uint vendor_cmd,
uint vendor_subcmd);
+/**
+ * tpm2_auto_start() - start up the TPM and perform selftests.
+ * If a testable function has not been tested and is
+ * requested the TPM2 will return TPM_RC_NEEDS_TEST.
+ *
+ * @param dev TPM device
+ * Return: TPM2_RC_TESTING, if TPM2 self-test is in progress.
+ * TPM2_RC_SUCCESS, if testing of all functions is complete without
+ * functional failures.
+ * TPM2_RC_FAILURE, if any test failed.
+ * TPM2_RC_INITIALIZE, if the TPM has not gone through the Startup
+ * sequence
+
+ */
+u32 tpm2_auto_start(struct udevice *dev);
+
#endif /* __TPM_V2_H */
diff --git a/include/tpm_api.h b/include/tpm_api.h
index 8979d9d..022a8bb 100644
--- a/include/tpm_api.h
+++ b/include/tpm_api.h
@@ -331,4 +331,12 @@
return IS_ENABLED(CONFIG_TPM_V2) && tpm_get_version(dev) == TPM_V2;
}
+/**
+ * tpm_auto_start() - start up the TPM and perform selftests
+ *
+ * @param dev TPM device
+ * Return: return code of the operation (0 = success)
+ */
+u32 tpm_auto_start(struct udevice *dev);
+
#endif /* __TPM_API_H */
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 697b982..895b093 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -44,6 +44,31 @@
return tpm_sendrecv_command(dev, command_v2, NULL, NULL);
}
+u32 tpm2_auto_start(struct udevice *dev)
+{
+ u32 rc;
+
+ /*
+ * the tpm_init() will return -EBUSY if the init has already happened
+ * The selftest and startup code can run multiple times with no side
+ * effects
+ */
+ rc = tpm_init(dev);
+ if (rc && rc != -EBUSY)
+ return rc;
+ rc = tpm2_self_test(dev, TPMI_YES);
+
+ if (rc == TPM2_RC_INITIALIZE) {
+ rc = tpm2_startup(dev, TPM2_SU_CLEAR);
+ if (rc)
+ return rc;
+
+ rc = tpm2_self_test(dev, TPMI_YES);
+ }
+
+ return rc;
+}
+
u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,
const ssize_t pw_sz)
{
diff --git a/lib/tpm_api.c b/lib/tpm_api.c
index 7e8df87..5b2c11a 100644
--- a/lib/tpm_api.c
+++ b/lib/tpm_api.c
@@ -35,6 +35,14 @@
}
}
+u32 tpm_auto_start(struct udevice *dev)
+{
+ if (tpm_is_v2(dev))
+ return tpm2_auto_start(dev);
+
+ return -ENOSYS;
+}
+
u32 tpm_resume(struct udevice *dev)
{
if (tpm_is_v1(dev))