Reference Camera v2 HAL Implementation

This is meant to be an example and a reference for device manufacturers
on how to build a new Camera v2 HAL.  This first patch has basic
configuration and entry/exit.

Change-Id: Ib4166e2eadb813228af38ec31a1215940c070bbf

4 files changed, 328 insertions, 0 deletions

diff --git a/modules/camera/Android.mk b/modules/camera/Android.mk
new file mode 100644
index 0000000..aa457f4
--- /dev/null
+++ b/modules/camera/Android.mk
@@ -0,0 +1,37 @@
+# Copyright (C) 2012 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := camera.default
+LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
+
+LOCAL_C_INCLUDES += \
+	system/media/camera/include \
+
+LOCAL_SRC_FILES := \
+	CameraHAL.cpp \
+	Camera.cpp \
+
+LOCAL_SHARED_LIBRARIES := \
+	libcamera_metadata \
+	liblog \
+
+LOCAL_CFLAGS += -Wall -Wextra
+
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/modules/camera/Camera.cpp b/modules/camera/Camera.cpp
new file mode 100644
index 0000000..24cfe4f
--- /dev/null
+++ b/modules/camera/Camera.cpp
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstdlib>
+#include <pthread.h>
+
+#define LOG_NDEBUG 0
+#define LOG_TAG "Camera"
+#include <cutils/log.h>
+
+#include "Camera.h"
+
+namespace default_camera_hal {
+
+extern "C" {
+// Shim passed to the framework to close an opened device.
+static int close_device(hw_device_t* dev)
+{
+    camera2_device_t* cam_dev = reinterpret_cast<camera2_device_t*>(dev);
+    Camera* cam = static_cast<Camera*>(cam_dev->priv);
+    return cam->close();
+}
+} // extern "C"
+
+Camera::Camera(int id, const hw_module_t* module)
+    : mId(id),
+      mBusy(false),
+      mMetadata(NULL)
+{
+    pthread_mutex_init(&mMutex,
+                       NULL); // No pthread mutex attributes.
+
+    // TODO: fill in device operations function pointers
+    mDevice.common.tag    = HARDWARE_DEVICE_TAG;
+    mDevice.common.module = const_cast<hw_module_t*>(module);
+    mDevice.common.close  = close_device;
+    mDevice.priv          = this;
+}
+
+Camera::~Camera()
+{
+}
+
+int Camera::open()
+{
+    ALOGV("%s: camera id %d", __func__, mId);
+    pthread_mutex_lock(&mMutex);
+    if (mBusy) {
+        pthread_mutex_unlock(&mMutex);
+        ALOGE("%s:id%d: Error, device already in use.", __func__, mId);
+        return -EBUSY;
+    }
+
+    // TODO: open camera dev nodes, etc
+    mBusy = true;
+
+    pthread_mutex_unlock(&mMutex);
+    return 0;
+}
+
+int Camera::close()
+{
+    ALOGV("%s: camera id %d", __func__, mId);
+    pthread_mutex_lock(&mMutex);
+    if (!mBusy) {
+        pthread_mutex_unlock(&mMutex);
+        ALOGE("%s:id%d: Error, close() on not open device.", __func__, mId);
+        return -EINVAL;
+    }
+
+    // TODO: close camera dev nodes, etc
+    mBusy = false;
+
+    pthread_mutex_unlock(&mMutex);
+    return 0;
+}
+
+int Camera::getCameraInfo(struct camera_info* info)
+{
+    ALOGV("%s: camera id %d: info=%p", __func__, mId, info);
+    init();
+    if (mMetadata == NULL) {
+        ALOGE("%s:id%d: unable to initialize metadata.", __func__, mId);
+        return -ENOENT;
+    }
+
+    // TODO: fill remainder of info struct
+    info->static_camera_characteristics = mMetadata;
+
+    return 0;
+}
+
+void Camera::init()
+{
+    pthread_mutex_lock(&mMutex);
+    if (mMetadata != NULL) {
+        pthread_mutex_unlock(&mMutex);
+        return;
+    }
+
+    // TODO: init metadata, dummy value for now
+    mMetadata = allocate_camera_metadata(1,1);
+
+    pthread_mutex_unlock(&mMutex);
+}
+
+} // namespace default_camera_hal
diff --git a/modules/camera/Camera.h b/modules/camera/Camera.h
new file mode 100644
index 0000000..72cbde2
--- /dev/null
+++ b/modules/camera/Camera.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CAMERA_H_
+#define CAMERA_H_
+
+#include <pthread.h>
+#include <hardware/camera2.h>
+
+namespace default_camera_hal {
+// Camera represents a physical camera on a device.
+// This is constructed when the HAL module is loaded, one per physical camera.
+// It is opened by the framework, and must be closed before it can be opened
+// again.
+// Also, the framework can query for camera metadata with getCameraInfo.
+// For the first query, the metadata must first be allocated and initialized,
+// but once done it is used for all future calls.
+// It is protected by @mMutex, and functions that modify the Camera object hold
+// this lock when performing modifications.  Currently these functions are:
+// @open, @close, and @init.
+class Camera {
+    public:
+        // id is used to distinguish cameras. 0 <= id < NUM_CAMERAS.
+        // module is a handle to the HAL module, used when the device is opened.
+        Camera(int id, const hw_module_t* module);
+        ~Camera();
+        // Open this camera, preparing it for use. Returns nonzero on failure.
+        int open();
+        // Close this camera. Returns nonzero on failure.
+        int close();
+        // Query for camera metadata, filling info struct. Returns nonzero if
+        // allocation or initialization failed.
+        int getCameraInfo(struct camera_info* info);
+        // Handle to this device passed to framework in response to open().
+        camera2_device_t mDevice;
+    private:
+        // One-time initialization of camera metadata.
+        void init();
+        // Identifier used by framework to distinguish cameras
+        int mId;
+        // True indicates camera is already open.
+        bool mBusy;
+        // Camera characteristics. NULL means it has not been allocated yet.
+        camera_metadata_t* mMetadata;
+        // Lock protecting the Camera object for modifications
+        pthread_mutex_t mMutex;
+};
+} // namespace default_camera_hal
+
+#endif // CAMERA_H_
diff --git a/modules/camera/CameraHAL.cpp b/modules/camera/CameraHAL.cpp
new file mode 100644
index 0000000..22c7aef
--- /dev/null
+++ b/modules/camera/CameraHAL.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstdlib>
+#include <hardware/camera2.h>
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "CameraHAL"
+#include <cutils/log.h>
+
+#include "Camera.h"
+
+/*
+ * This file serves as the entry point to the HAL.  It contains the module
+ * structure and functions used by the framework to load and interface to this
+ * HAL, as well as the handles to the individual camera devices.
+ */
+
+namespace default_camera_hal {
+
+enum camera_id_t {
+    CAMERA_A,
+    CAMERA_B,
+    NUM_CAMERAS
+};
+
+// Symbol used by the framework when loading the HAL, defined below.
+extern "C" camera_module_t HAL_MODULE_INFO_SYM;
+
+// Camera devices created when the module is loaded. See Camera.h
+static Camera gCameras[NUM_CAMERAS] = {
+    Camera(CAMERA_A, &HAL_MODULE_INFO_SYM.common),
+    Camera(CAMERA_B, &HAL_MODULE_INFO_SYM.common)
+};
+
+extern "C" {
+
+static int get_number_of_cameras()
+{
+    ALOGV("%s", __func__);
+    return NUM_CAMERAS;
+}
+
+static int get_camera_info(int id, struct camera_info* info)
+{
+    ALOGV("%s: camera id %d: info=%p", __func__, id, info);
+    if (id < 0 || id >= NUM_CAMERAS) {
+        ALOGE("%s: Invalid camera id %d", __func__, id);
+        return -ENODEV;
+    }
+    return gCameras[id].getCameraInfo(info);
+}
+
+static int open_device(const hw_module_t* module,
+                       const char* name,
+                       hw_device_t** device)
+{
+    ALOGV("%s: module=%p, name=%s, device=%p", __func__, module, name, device);
+    char *nameEnd;
+    int id;
+
+    id = strtol(name, &nameEnd, 10);
+    if (nameEnd != NULL) {
+        ALOGE("%s: Invalid camera id name %s", __func__, name);
+        return -EINVAL;
+    } else if (id < 0 || id >= NUM_CAMERAS) {
+        ALOGE("%s: Invalid camera id %d", __func__, id);
+        return -ENODEV;
+    }
+    *device = &gCameras[id].mDevice.common;
+    return gCameras[id].open();
+}
+
+static hw_module_methods_t gCameraModuleMethods = {
+    open : open_device
+};
+
+camera_module_t HAL_MODULE_INFO_SYM = {
+    common : {
+        tag                : HARDWARE_MODULE_TAG,
+        module_api_version : CAMERA_MODULE_API_VERSION_2_0,
+        hal_api_version    : HARDWARE_HAL_API_VERSION,
+        id                 : CAMERA_HARDWARE_MODULE_ID,
+        name               : "Reference Camera v2 HAL",
+        author             : "The Android Open Source Project",
+        methods            : &gCameraModuleMethods,
+        dso                : NULL,
+        reserved           : {0},
+    },
+    get_number_of_cameras : get_number_of_cameras,
+    get_camera_info       : get_camera_info
+};
+
+} // extern "C"
+} // namespace default_camera_hal