WIP: Camera HAL module 2.1, device 2.1

- Support a simple callback from camera HAL module to framework, to
  indicate a change to module configuration or status.

- Add support for per-instance metadata to camera 2 device HAL.

Change-Id: I25699ff096c4f3578b9e54c7e6e60ce2449adc82

include/hardware/camera2.h

@@ -21,17 +21,17 @@
 #include "system/camera_metadata.h"
 
 /**
- * Camera device HAL 2.0 [ CAMERA_DEVICE_API_VERSION_2_0 ]
+ * Camera device HAL 2.1 [ CAMERA_DEVICE_API_VERSION_2_0, CAMERA_DEVICE_API_VERSION_2_1 ]
  *
  * EXPERIMENTAL.
  *
  * Supports the android.hardware.Camera APIs.
  *
  * Camera devices that support this version of the HAL must return
- * CAMERA_DEVICE_API_VERSION_2_0 in camera_device_t.common.version and in
+ * CAMERA_DEVICE_API_VERSION_2_1 in camera_device_t.common.version and in
  * camera_info_t.device_version (from camera_module_t.get_camera_info).
  *
- * Camera modules that may contain version 2.0 devices must implement at least
+ * Camera modules that may contain version 2.x devices must implement at least
  * version 2.0 of the camera module interface (as defined by
  * camera_module_t.common.module_api_version).
  *
@@ -39,11 +39,15 @@
  *
  * Version history:
  *
- * 2.0: Initial release (Android 4.2):
+ * 2.0: CAMERA_DEVICE_API_VERSION_2_0. Initial release (Android 4.2):
  *      - Sufficient for implementing existing android.hardware.Camera API.
  *      - Allows for ZSL queue in camera service layer
  *      - Not tested for any new features such manual capture control,
  *        Bayer RAW capture, reprocessing of RAW data.
+ *
+ * 2.1: CAMERA_DEVICE_API_VERSION_2_1. Support per-device static metadata:
+ *      - Add get_instance_metadata() method to retrieve metadata that is fixed
+ *        after device open, but may be variable between open() calls.
  */
 
 __BEGIN_DECLS
@@ -792,6 +796,26 @@ typedef struct camera2_device_ops {
      */
     int (*dump)(const struct camera2_device *, int fd);
 
+    /**
+     * Get device-instance-specific metadata. This metadata must be constant for
+     * a single instance of the camera device, but may be different between
+     * open() calls. The returned camera_metadata pointer must be valid until
+     * the device close() method is called.
+     *
+     * Version information:
+     *
+     * CAMERA_DEVICE_API_VERSION_2_0:
+     *
+     *   Not available. Framework may not access this function pointer.
+     *
+     * CAMERA_DEVICE_API_VERSION_2_1:
+     *
+     *   Valid. Can be called by the framework.
+     *
+     */
+    int (*get_instance_metadata)(const struct camera2_device *,
+            camera_metadata **instance_metadata);
+
 } camera2_device_ops_t;
 
 /**********************************************************************