commit 9eda9bf8124bc254d51afb95c7eaa61cceeb5d81
author John Stultz <john.stultz@linaro.org> Fri Jan 08 00:41:13 2021 +0000
committer John Stultz <john.stultz@linaro.org> Fri Jan 08 05:11:55 2021 +0000
tree 6458074b542f421297bd1cf47808bd92a388c46a
parent 980553b0b6bd41a0086ba436c3b0159495559ec7

Codec2: Integrate support for the system-uncached DMA BUF Heap

While not yet upstream, the system-uncached heap has been added
to android12-5.10, so lets enable support for selecting it on
buffers who's usage flags are not set to C2MemoryUsage::CPU_READ
or C2MemoryUsage::CPU_WRITE.

Because it isn't guarenteed to exist, this adds a helper
function to check if system-uncached is supported as well, so
devices without it can fall back to the system heap.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I525525cae85b6759e460598c454f1e5f150391f9

media/codec2/vndk/C2DmaBufAllocator.cpp

diff --git a/media/codec2/vndk/C2DmaBufAllocator.cpp b/media/codec2/vndk/C2DmaBufAllocator.cpp
index 59e82e2..750aa31 100644
--- a/media/codec2/vndk/C2DmaBufAllocator.cpp
+++ b/media/codec2/vndk/C2DmaBufAllocator.cpp
@@ -315,8 +315,8 @@
         if (mUsageMapper) {
             res = mUsageMapper(usage, capacity, heap_name, flags);
         } else {
-            // No system-uncached yet, so disabled for now
-            if (0 && !(usage.expected & (C2MemoryUsage::CPU_READ | C2MemoryUsage::CPU_WRITE)))
+            if (C2DmaBufAllocator::system_uncached_supported() &&
+                !(usage.expected & (C2MemoryUsage::CPU_READ | C2MemoryUsage::CPU_WRITE)))
                 *heap_name = "system-uncached";
             else
                 *heap_name = "system";

media/codec2/vndk/C2Store.cpp

diff --git a/media/codec2/vndk/C2Store.cpp b/media/codec2/vndk/C2Store.cpp
index 1e907c1..6c82d15 100644
--- a/media/codec2/vndk/C2Store.cpp
+++ b/media/codec2/vndk/C2Store.cpp
@@ -780,7 +780,13 @@
                 };
 
                 static C2R setDmaBufUsage(bool /* mayBlock */, C2P<C2StoreDmaBufUsageInfo> &me) {
-                    strncpy(me.set().m.heapName, "system", me.v.flexCount());
+                    long long usage = (long long)me.get().m.usage;
+                    if (C2DmaBufAllocator::system_uncached_supported() &&
+                        !(usage & (C2MemoryUsage::CPU_READ | C2MemoryUsage::CPU_WRITE))) {
+                        strncpy(me.set().m.heapName, "system-uncached", me.v.flexCount());
+                    } else {
+                        strncpy(me.set().m.heapName, "system", me.v.flexCount());
+                    }
                     me.set().m.allocFlags = 0;
                     return C2R::Ok();
                 };

media/codec2/vndk/include/C2DmaBufAllocator.h

diff --git a/media/codec2/vndk/include/C2DmaBufAllocator.h b/media/codec2/vndk/include/C2DmaBufAllocator.h
index abb8307..d84c8c6 100644
--- a/media/codec2/vndk/include/C2DmaBufAllocator.h
+++ b/media/codec2/vndk/include/C2DmaBufAllocator.h
@@ -84,6 +84,16 @@
     void setUsageMapper(const UsageMapperFn& mapper, uint64_t minUsage, uint64_t maxUsage,
                         uint64_t blockSize);
 
+    static bool system_uncached_supported(void) {
+        static int cached_result = -1;
+
+        if (cached_result == -1) {
+            struct stat buffer;
+            cached_result = (stat("/dev/dma_heap/system-uncached", &buffer) == 0);
+        }
+        return (cached_result == 1);
+    };
+
    private:
     c2_status_t mInit;
     BufferAllocator mBufferAllocator;