dma-buf: add vmap interface

The main requirement I have for this interface is for scanning out
using the USB gpu devices. Since these devices have to read the
framebuffer on updates and linearly compress it, using kmaps
is a major overhead for every update.

v2: fix warn issues pointed out by Sylwester Nawrocki.

v3: fix compile !CONFIG_DMA_SHARED_BUFFER and add _GPL for now

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 1f78d1594cc7..a02b1ff6488e 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -98,6 +98,9 @@ struct dma_buf_ops {
         void (*kunmap)(struct dma_buf *, unsigned long, void *);
 
         int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
+
+        void *(*vmap)(struct dma_buf *);
+        void (*vunmap)(struct dma_buf *, void *vaddr);
 };
 
 /**
@@ -176,6 +179,8 @@ void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
 
 int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
                  unsigned long);
+void *dma_buf_vmap(struct dma_buf *);
+void dma_buf_vunmap(struct dma_buf *, void *vaddr);
 #else
 
 static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
@@ -264,6 +269,15 @@ static inline int dma_buf_mmap(struct dma_buf *dmabuf,
 {
         return -ENODEV;
 }
+
+static inline void *dma_buf_vmap(struct dma_buf *dmabuf)
+{
+        return NULL;
+}
+
+static inline void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
+{
+}
 #endif /* CONFIG_DMA_SHARED_BUFFER */
 
 #endif /* __DMA_BUF_H__ */