Initial Android Auto External View Systems drivers

Add support for EVS system camera and display drivers.
These build and run but still contain significant placeholder code and
TODO items.

Bug: 32095143
Test:  run against evs_test (submitted in future change set)
Change-Id: I9187e888f03248e5cd43293253dc76a71184c02d
diff --git a/evs/1.0/default/EvsDisplay.cpp b/evs/1.0/default/EvsDisplay.cpp
new file mode 100644
index 0000000..9dba6fc
--- /dev/null
+++ b/evs/1.0/default/EvsDisplay.cpp
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#define LOG_TAG "android.hardware.evs@1.0-service"
+
+#include "EvsDisplay.h"
+
+#include <ui/GraphicBufferAllocator.h>
+#include <ui/GraphicBufferMapper.h>
+
+
+namespace android {
+namespace hardware {
+namespace evs {
+namespace V1_0 {
+namespace implementation {
+
+
+// TODO(b/31632518):  Need to get notification when our client dies so we can close the camera.
+// As it stands, if the client dies suddently, the buffer may be stranded.
+// As possible work around would be to give the client a HIDL object to exclusively hold
+// and use it's destructor to perform some work in the server side.
+
+
+EvsDisplay::EvsDisplay() {
+    ALOGD("EvsDisplay instantiated");
+
+    // Set up our self description
+    mInfo.displayId             = "Mock Display";
+    mInfo.vendorFlags           = 3870;
+    mInfo.defaultHorResolution  = 320;
+    mInfo.defaultVerResolution  = 240;
+}
+
+
+EvsDisplay::~EvsDisplay() {
+    ALOGD("EvsDisplay being destroyed");
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // Report if we're going away while a buffer is outstanding.  This could be bad.
+    if (mFrameBusy) {
+        ALOGE("EvsDisplay going down while client is holding a buffer\n");
+    }
+
+    // Make sure we release our frame buffer
+    if (mBuffer) {
+        // Drop the graphics buffer we've been using
+        GraphicBufferAllocator& alloc(GraphicBufferAllocator::get());
+        alloc.free(mBuffer);
+    }
+    ALOGD("EvsDisplay destroyed");
+}
+
+
+/**
+ * Returns basic information about the EVS display provided by the system.
+ * See the description of the DisplayDesc structure below for details.
+ */
+Return<void> EvsDisplay::getDisplayInfo(getDisplayInfo_cb _hidl_cb)  {
+    ALOGD("getDisplayInfo");
+
+    // Send back our self description
+    _hidl_cb(mInfo);
+    return Void();
+}
+
+
+/**
+ * Clients may set the display state to express their desired state.
+ * The HAL implementation must gracefully accept a request for any state
+ * while in any other state, although the response may be to ignore the request.
+ * The display is defined to start in the NOT_VISIBLE state upon initialization.
+ * The client is then expected to request the VISIBLE_ON_NEXT_FRAME state, and
+ * then begin providing video.  When the display is no longer required, the client
+ * is expected to request the NOT_VISIBLE state after passing the last video frame.
+ */
+Return<EvsResult> EvsDisplay::setDisplayState(DisplayState state) {
+    ALOGD("setDisplayState");
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // Ensure we recognize the requested state so we don't go off the rails
+    if (state < DisplayState::NUM_STATES) {
+        // Record the requested state
+        mRequestedState = state;
+        return EvsResult::OK;
+    }
+    else {
+        // Turn off the display if asked for an unrecognized state
+        mRequestedState = DisplayState::NOT_VISIBLE;
+        return EvsResult::INVALID_ARG;
+    }
+}
+
+
+/**
+ * The HAL implementation should report the actual current state, which might
+ * transiently differ from the most recently requested state.  Note, however, that
+ * the logic responsible for changing display states should generally live above
+ * the device layer, making it undesirable for the HAL implementation to
+ * spontaneously change display states.
+ */
+Return<DisplayState> EvsDisplay::getDisplayState()  {
+    ALOGD("getDisplayState");
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // At the moment, we treat the requested state as immediately active
+    DisplayState currentState = mRequestedState;
+
+    return currentState;
+}
+
+
+/**
+ * This call returns a handle to a frame buffer associated with the display.
+ * This buffer may be locked and written to by software and/or GL.  This buffer
+ * must be returned via a call to returnTargetBufferForDisplay() even if the
+ * display is no longer visible.
+ */
+// TODO: We need to know if/when our client dies so we can get the buffer back! (blocked b/31632518)
+Return<void> EvsDisplay::getTargetBuffer(getTargetBuffer_cb _hidl_cb)  {
+    ALOGD("getTargetBuffer");
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // If we don't already have a buffer, allocate one now
+    if (!mBuffer) {
+        GraphicBufferAllocator& alloc(GraphicBufferAllocator::get());
+        status_t result = alloc.allocate(mInfo.defaultHorResolution, mInfo.defaultVerResolution,
+                                         HAL_PIXEL_FORMAT_RGBA_8888, 1,
+                                         GRALLOC_USAGE_HW_FB | GRALLOC_USAGE_HW_COMPOSER,
+                                         &mBuffer, &mStride, 0, "EvsDisplay");
+        mFrameBusy = false;
+        ALOGD("Allocated new buffer %p with stride %u", mBuffer, mStride);
+    }
+
+    // Do we have a frame available?
+    if (mFrameBusy) {
+        // This means either we have a 2nd client trying to compete for buffers
+        // (an unsupported mode of operation) or else the client hasn't returned
+        // a previously issues buffer yet (they're behaving badly).
+        // NOTE:  We have to make callback even if we have nothing to provide
+        ALOGE("getTargetBuffer called while no buffers available.");
+        _hidl_cb(nullptr);
+    }
+    else {
+        // Mark our buffer as busy
+        mFrameBusy = true;
+
+        // Send the buffer to the client
+        ALOGD("Providing display buffer %p", mBuffer);
+        _hidl_cb(mBuffer);
+    }
+
+    // All done
+    return Void();
+}
+
+
+/**
+ * This call tells the display that the buffer is ready for display.
+ * The buffer is no longer valid for use by the client after this call.
+ */
+Return<EvsResult> EvsDisplay::returnTargetBufferForDisplay(const hidl_handle& bufferHandle)  {
+    ALOGD("returnTargetBufferForDisplay %p", bufferHandle.getNativeHandle());
+    std::lock_guard<std::mutex> lock(mAccessLock);
+
+    // This shouldn't happen if we haven't issued the buffer!
+    if (!bufferHandle) {
+        ALOGE ("returnTargetBufferForDisplay called without a valid buffer handle.\n");
+        return EvsResult::INVALID_ARG;
+    }
+    /* TODO(b/33492405): It would be nice to validate we got back the buffer we expect,
+     * but HIDL doesn't support that (yet?)
+    if (bufferHandle != mBuffer) {
+        ALOGE ("Got an unrecognized frame returned.\n");
+        return EvsResult::INVALID_ARG;
+    }
+    */
+    if (!mFrameBusy) {
+        ALOGE ("A frame was returned with no outstanding frames.\n");
+        return EvsResult::BUFFER_NOT_AVAILABLE;
+    }
+
+    mFrameBusy = false;
+
+    // If we were waiting for a new frame, this is it!
+    if (mRequestedState == DisplayState::VISIBLE_ON_NEXT_FRAME) {
+        mRequestedState = DisplayState::VISIBLE;
+    }
+
+    // Validate we're in an expected state
+    if (mRequestedState != DisplayState::VISIBLE) {
+        // We shouldn't get frames back when we're not visible.
+        ALOGE ("Got an unexpected frame returned while not visible - ignoring.\n");
+    }
+    else {
+        // Make this buffer visible
+        // TODO:  Add code to put this image on the screen (or validate it somehow?)
+    }
+
+    return EvsResult::OK;
+}
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace evs
+} // namespace hardware
+} // namespace android