android: ion: add ION_FLAG_MAY_HWRENDER

Clients of ION in userland can specify if the allocated buffer is
written by H/W like GPU before S/W initializes it. If the cache
maintenance is fully supported by all H/Ws that touch the buffer or
all H/Ws touching the buffer are in the same cache coherency domain,
everything goes right. But the problem occurs due to the drivers that
does not perform cache maintenance due to the performance reason.
For the the different H/Ws that touch the same buffer in the different
cache coherency domain, the drivers should care when creating IO
memory mapping. ION_FLAG_MAY_HWRENDER and ion_hwrender_dmabuf() helper
give information to such drivers if the buffer is initialized by H/W.
ION_FLAG_MAY_HWRENDER effects nonthing in ION. Just documentation
purpose.

Change-Id: Iab6293f2c5d6017cf67378356721de4256f049b9
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>

diff --git a/drivers/staging/android/ion/ion_exynos.c b/drivers/staging/android/ion/ion_exynos.c
index 72350f8bce3ef2c42b5f39aa367f044558c35041..11f18675fade63cf0c3729f77fe1e22f540ca96e 100644 (file)
--- a/drivers/staging/android/ion/ion_exynos.c
+++ b/drivers/staging/android/ion/ion_exynos.c
@@ -39,6 +39,13 @@ bool ion_cached_dmabuf(struct dma_buf *dmabuf)
        return ion_buffer_cached(dmabuf->priv);
 }
 
+bool ion_hwrender_dmabuf(struct dma_buf *dmabuf)
+{
+       struct ion_buffer *buffer = dmabuf->priv;
+
+       return !!(buffer->flags & ION_FLAG_MAY_HWRENDER);
+}
+
 struct ion_iovm_map {
        struct list_head list;
        struct device *dev;

diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
index d480b4f754b9e629ccdd212a2cfa11d35403ac33..7c111bbf54ab6e87741b9a9d4924609a0cacc837 100644 (file)
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -76,6 +76,11 @@ enum ion_heap_type {
  * overhead by explicit cache maintenance.
  */
 #define ION_FLAG_SYNC_FORCE 32
+/*
+ * the allocated buffer is possibly written by H/W(GPU) before initializing by
+ * S/W except buffer initialization by ION on allocation.
+ */
+#define ION_FLAG_MAY_HWRENDER 64
 
 /**
  * DOC: Ion Userspace API

diff --git a/include/linux/ion_exynos.h b/include/linux/ion_exynos.h
index 8a40bc38549017874fd1f031746df8c2fcd1d3c1..bde99e7b6e727ea7acb76454c34790c4c915c658 100644 (file)
--- a/include/linux/ion_exynos.h
+++ b/include/linux/ion_exynos.h
@@ -27,16 +27,23 @@ struct dma_buf_attachment;
 struct dma_buf *ion_alloc_dmabuf(const char *heap_name,
                                 size_t len, unsigned int flags);
 bool ion_cached_dmabuf(struct dma_buf *dmabuf);
+bool ion_hwrender_dmabuf(struct dma_buf *dmabuf);
 #else
 static inline struct dma_buf *ion_alloc_dmabuf(const char *heap_name,
                                               size_t len, unsigned int flags)
 {
        return ERR_PTR(-ENODEV);
 }
+
 static inline bool ion_cached_dmabuf(struct dma_buf *dmabuf)
 {
        return false;
 }
+
+static inline bool ion_cached_hwrender(struct dma_buf *dmabuf)
+{
+       return false;
+}
 #endif
 
 #if defined(CONFIG_EXYNOS_IOVMM) && defined(CONFIG_ION_EXYNOS)