dm: tpm: Add a uclass for Trusted Platform Modules

Add a new uclass for TPMs which uses almost the same TIS (TPM Interface
Specification) as is currently implemented. Since init() is handled by the
normal driver model probe() method, we don't need to implement that. Also
rename the transfer method to xfer() which is a less clumbsy name.

Once all drivers and users are converted to driver model we can remove the
old code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Christophe Ricard<christophe-h.ricard@st.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

1 files changed, 192 insertions, 0 deletions

diff --git a/include/tpm.h b/include/tpm.h
index 88aeba28e3..e4472d3ed4 100644
--- a/include/tpm.h
+++ b/include/tpm.h
@@ -15,6 +15,17 @@
  * Specification for definitions of TPM commands.
  */
 
+#define TPM_HEADER_SIZE		10
+
+enum tpm_duration {
+	TPM_SHORT = 0,
+	TPM_MEDIUM = 1,
+	TPM_LONG = 2,
+	TPM_UNDEFINED,
+
+	TPM_DURATION_COUNT,
+};
+
 enum tpm_startup_type {
 	TPM_ST_CLEAR		= 0x0001,
 	TPM_ST_STATE		= 0x0002,
@@ -152,6 +163,187 @@ enum tpm_return_code {
 	TPM_DEFEND_LOCK_RUNNING	= TPM_BASE + TPM_NON_FATAL + 3,
 };
 
+#ifdef CONFIG_DM_TPM
+
+/* Max buffer size supported by our tpm */
+#define TPM_DEV_BUFSIZE		1260
+
+/**
+ * struct tpm_chip_priv - Information about a TPM, stored by the uclass
+ *
+ * These values must be set up by the device's probe() method before
+ * communcation is attempted. If the device has an xfer() method, this is
+ * not needed. There is no need to set up @buf.
+ *
+ * @duration_ms:	Length of each duration type in milliseconds
+ * @retry_time_ms:	Time to wait before retrying receive
+ */
+struct tpm_chip_priv {
+	uint duration_ms[TPM_DURATION_COUNT];
+	uint retry_time_ms;
+	u8 buf[TPM_DEV_BUFSIZE + sizeof(u8)];  /* Max buffer size + addr */
+};
+
+/**
+ * struct tpm_ops - low-level TPM operations
+ *
+ * These are designed to avoid loops and delays in the driver itself. These
+ * should be handled in the uclass.
+ *
+ * In gneral you should implement everything except xfer(). Where you need
+ * complete control of the transfer, then xfer() can be provided and will
+ * override the other methods.
+ *
+ * This interface is for low-level TPM access. It does not understand the
+ * concept of localities or the various TPM messages. That interface is
+ * defined in the functions later on in this file, but they all translate
+ * to bytes which are sent and received.
+ */
+struct tpm_ops {
+	/**
+	 * open() - Request access to locality 0 for the caller
+	 *
+	 * After all commands have been completed the caller should call
+	 * close().
+	 *
+	 * @dev:	Device to close
+	 * @return 0 ok OK, -ve on error
+	 */
+	int (*open)(struct udevice *dev);
+
+	/**
+	 * close() - Close the current session
+	 *
+	 * Releasing the locked locality. Returns 0 on success, -ve 1 on
+	 * failure (in case lock removal did not succeed).
+	 *
+	 * @dev:	Device to close
+	 * @return 0 ok OK, -ve on error
+	 */
+	int (*close)(struct udevice *dev);
+
+	/**
+	 * get_desc() - Get a text description of the TPM
+	 *
+	 * @dev:	Device to check
+	 * @buf:	Buffer to put the string
+	 * @size:	Maximum size of buffer
+	 * @return length of string, or -ENOSPC it no space
+	 */
+	int (*get_desc)(struct udevice *dev, char *buf, int size);
+
+	/**
+	 * send() - send data to the TPM
+	 *
+	 * @dev:	Device to talk to
+	 * @sendbuf:	Buffer of the data to send
+	 * @send_size:	Size of the data to send
+	 *
+	 * Returns 0 on success or -ve on failure.
+	 */
+	int (*send)(struct udevice *dev, const uint8_t *sendbuf,
+		    size_t send_size);
+
+	/**
+	 * recv() - receive a response from the TPM
+	 *
+	 * @dev:	Device to talk to
+	 * @recvbuf:	Buffer to save the response to
+	 * @max_size:	Maximum number of bytes to receive
+	 *
+	 * Returns number of bytes received on success, -EAGAIN if the TPM
+	 * response is not ready, -EINTR if cancelled, or other -ve value on
+	 * failure.
+	 */
+	int (*recv)(struct udevice *dev, uint8_t *recvbuf, size_t max_size);
+
+	/**
+	 * cleanup() - clean up after an operation in progress
+	 *
+	 * This is called if receiving times out. The TPM may need to abort
+	 * the current transaction if it did not complete, and make itself
+	 * ready for another.
+	 *
+	 * @dev:	Device to talk to
+	 */
+	int (*cleanup)(struct udevice *dev);
+
+	/**
+	 * xfer() - send data to the TPM and get response
+	 *
+	 * This method is optional. If it exists it is used in preference
+	 * to send(), recv() and cleanup(). It should handle all aspects of
+	 * TPM communication for a single transfer.
+	 *
+	 * @dev:	Device to talk to
+	 * @sendbuf:	Buffer of the data to send
+	 * @send_size:	Size of the data to send
+	 * @recvbuf:	Buffer to save the response to
+	 * @recv_size:	Pointer to the size of the response buffer
+	 *
+	 * Returns 0 on success (and places the number of response bytes at
+	 * recv_size) or -ve on failure.
+	 */
+	int (*xfer)(struct udevice *dev, const uint8_t *sendbuf,
+		    size_t send_size, uint8_t *recvbuf, size_t *recv_size);
+};
+
+#define tpm_get_ops(dev)        ((struct tpm_ops *)device_get_ops(dev))
+
+/**
+ * tpm_open() - Request access to locality 0 for the caller
+ *
+ * After all commands have been completed the caller is supposed to
+ * call tpm_close().
+ *
+ * Returns 0 on success, -ve on failure.
+ */
+int tpm_open(struct udevice *dev);
+
+/**
+ * tpm_close() - Close the current session
+ *
+ * Releasing the locked locality. Returns 0 on success, -ve 1 on
+ * failure (in case lock removal did not succeed).
+ */
+int tpm_close(struct udevice *dev);
+
+/**
+ * tpm_get_desc() - Get a text description of the TPM
+ *
+ * @dev:	Device to check
+ * @buf:	Buffer to put the string
+ * @size:	Maximum size of buffer
+ * @return length of string, or -ENOSPC it no space
+ */
+int tpm_get_desc(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
+ * recv() to get the reply. If recv() returns -EAGAIN then it will delay a
+ * short time and then call recv() again.
+ *
+ * Regardless of whether recv() completes successfully, it will then call
+ * cleanup() to finish the transaction.
+ *
+ * Note that the outgoing data is inspected to determine command type
+ * (ordinal) and a timeout is used for that command type.
+ *
+ * @sendbuf - buffer of the data to send
+ * @send_size size of the data to send
+ * @recvbuf - memory to save the response to
+ * @recv_len - pointer to the size of the response buffer
+ *
+ * Returns 0 on success (and places the number of response bytes at
+ * recv_len) or -ve on failure.
+ */
+int tpm_xfer(struct udevice *dev, const uint8_t *sendbuf, size_t send_size,
+	     uint8_t *recvbuf, size_t *recv_size);
+
+#endif /* CONFIG_DM_TPM */
+
 /**
  * Initialize TPM device.  It must be called before any TPM commands.
  *