Add gralloc usage conversion functions

Converting gralloc1 / ..graphics.allocator@2.0 usage to gralloc0 usage
requires more than just ORing bits and truncating: the CPU_READ_OFTEN
bits don't match up correctly. Add utility functions for converting
back and forth which handle this properly.

Test: boot bullhead-eng
Change-Id: I1cee972feaea486d5607c60acead2e870c2c9549
diff --git a/libgrallocusage/GrallocUsageConversion.cpp b/libgrallocusage/GrallocUsageConversion.cpp
new file mode 100644
index 0000000..8164beb
--- /dev/null
+++ b/libgrallocusage/GrallocUsageConversion.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2017 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 <grallocusage/GrallocUsageConversion.h>
+
+#include <android/hardware/graphics/allocator/2.0/types.h>
+#include <hardware/gralloc.h>
+
+using android::hardware::graphics::allocator::V2_0::ProducerUsage;
+using android::hardware::graphics::allocator::V2_0::ConsumerUsage;
+
+void android_convertGralloc0To1Usage(int32_t usage, uint64_t* producerUsage,
+                                     uint64_t* consumerUsage) {
+    constexpr uint64_t PRODUCER_MASK = ProducerUsage::CPU_READ |
+                                       /* ProducerUsage::CPU_READ_OFTEN | */
+                                       ProducerUsage::CPU_WRITE |
+                                       /* ProducerUsage::CPU_WRITE_OFTEN | */
+                                       ProducerUsage::GPU_RENDER_TARGET | ProducerUsage::PROTECTED |
+                                       ProducerUsage::CAMERA | ProducerUsage::VIDEO_DECODER |
+                                       ProducerUsage::SENSOR_DIRECT_DATA;
+    constexpr uint64_t CONSUMER_MASK = ConsumerUsage::CPU_READ |
+                                       /* ConsumerUsage::CPU_READ_OFTEN | */
+                                       ConsumerUsage::GPU_TEXTURE | ConsumerUsage::HWCOMPOSER |
+                                       ConsumerUsage::CLIENT_TARGET | ConsumerUsage::CURSOR |
+                                       ConsumerUsage::VIDEO_ENCODER | ConsumerUsage::CAMERA |
+                                       ConsumerUsage::RENDERSCRIPT | ConsumerUsage::GPU_DATA_BUFFER;
+    *producerUsage = static_cast<uint64_t>(usage) & PRODUCER_MASK;
+    *consumerUsage = static_cast<uint64_t>(usage) & CONSUMER_MASK;
+    if ((static_cast<uint32_t>(usage) & GRALLOC_USAGE_SW_READ_OFTEN) == GRALLOC_USAGE_SW_READ_OFTEN) {
+        *producerUsage |= ProducerUsage::CPU_READ_OFTEN;
+        *consumerUsage |= ConsumerUsage::CPU_READ_OFTEN;
+    }
+    if ((static_cast<uint32_t>(usage) & GRALLOC_USAGE_SW_WRITE_OFTEN) ==
+        GRALLOC_USAGE_SW_WRITE_OFTEN) {
+        *producerUsage |= ProducerUsage::CPU_WRITE_OFTEN;
+    }
+}
+
+int32_t android_convertGralloc1To0Usage(uint64_t producerUsage, uint64_t consumerUsage) {
+    static_assert(uint64_t(ConsumerUsage::CPU_READ_OFTEN) == uint64_t(ProducerUsage::CPU_READ_OFTEN),
+                  "expected ConsumerUsage and ProducerUsage CPU_READ_OFTEN bits to match");
+    uint64_t merged = producerUsage | consumerUsage;
+    if ((merged & (ConsumerUsage::CPU_READ_OFTEN)) != 0) {
+        merged &= ~uint64_t(ConsumerUsage::CPU_READ_OFTEN);
+        merged |= GRALLOC_USAGE_SW_READ_OFTEN;
+    }
+    if ((merged & (ProducerUsage::CPU_WRITE_OFTEN)) != 0) {
+        merged &= ~uint64_t(ProducerUsage::CPU_WRITE_OFTEN);
+        merged |= GRALLOC_USAGE_SW_WRITE_OFTEN;
+    }
+    return static_cast<int32_t>(merged);
+}