tpm: Allow reporting the internal state

It is useful to read information about the current TPM state, where
supported, e.g. for debugging purposes when verified boot fails.

Add support for this to the TPM interface as well as Cr50. Add a simple
sandbox test.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/include/tpm-common.h b/include/tpm-common.h
index a28629e..b2c5404 100644
--- a/include/tpm-common.h
+++ b/include/tpm-common.h
@@ -120,6 +120,16 @@
 	int (*get_desc)(struct udevice *dev, char *buf, int size);
 
 	/**
+	 * report_state() - Collect information about the current TPM state
+	 *
+	 * @dev:	Device to check
+	 * @buf:	Buffer to put the string
+	 * @size:	Maximum size of buffer
+	 * Return: return code of the operation (0 = success)
+	 */
+	int (*report_state)(struct udevice *dev, char *buf, int size);
+
+	/**
 	 * send() - send data to the TPM
 	 *
 	 * @dev:	Device to talk to
@@ -235,6 +245,16 @@
 int tpm_get_desc(struct udevice *dev, char *buf, int size);
 
 /**
+ * tpm_report_state() - Collect information about the current TPM state
+ *
+ * @dev:	Device to check
+ * @buf:	Buffer to put the string
+ * @size:	Maximum size of buffer
+ * Return: return code of the operation (0 = success)
+ */
+int tpm_report_state(struct udevice *dev, char *buf, int size);
+
+/**
  * tpm_xfer() - send data to the TPM and get response
  *
  * This first uses the device's send() method to send the bytes. Then it calls