On Fri, May 18, 2012 at 12:44 PM, Dave Airlie <airlied@xxxxxxxxx> wrote:
> From: Dave Airlie <airlied@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
Reviewed-by: Rob Clark <rob.clark@xxxxxxxxxx>
> ---
> drivers/base/dma-buf.c | 34 ++++++++++++++++++++++++++++++++++
> include/linux/dma-buf.h | 14 ++++++++++++++
> 2 files changed, 48 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
> index 07cbbc6..0d8197e 100644
> --- a/drivers/base/dma-buf.c
> +++ b/drivers/base/dma-buf.c
> @@ -406,3 +406,37 @@ void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
> dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
> }
> EXPORT_SYMBOL_GPL(dma_buf_kunmap);
> +
> +/**
> + * dma_buf_vmap - Create virtual mapping for the buffer object into kernel address space. The same restrictions as for vmap and friends apply.
> + * @dma_buf: [in] buffer to vmap
> + *
> + * This call may fail due to lack of virtual mapping address space.
> + * These calls are optional in drivers. The intended use for them
> + * is for mapping objects linear in kernel space for high use objects.
> + * Please attempt to use kmap/kunmap before thinking about these interfaces.
> + */
> +void *dma_buf_vmap(struct dma_buf *dmabuf)
> +{
> + if (WARN_ON(!dmabuf))
> + return NULL;
> +
> + if (dmabuf->ops->vmap)
> + return dmabuf->ops->vmap(dmabuf);
> + return NULL;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_vmap);
> +
> +/**
> + * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
> + * @dma_buf: [in] buffer to vmap
> + */
> +void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> +{
> + if (WARN_ON(!dmabuf))
> + return;
> +
> + if (dmabuf->ops->vunmap)
> + dmabuf->ops->vunmap(dmabuf, vaddr);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_vunmap);
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 3efbfc2..d8c2865 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -92,6 +92,9 @@ struct dma_buf_ops {
> void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *);
> void *(*kmap)(struct dma_buf *, unsigned long);
> void (*kunmap)(struct dma_buf *, unsigned long, void *);
> +
> + void *(*vmap)(struct dma_buf *);
> + void (*vunmap)(struct dma_buf *, void *vaddr);
> };
>
> /**
> @@ -167,6 +170,9 @@ void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
> void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
> void *dma_buf_kmap(struct dma_buf *, unsigned long);
> void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
> +
> +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,
> @@ -248,6 +254,14 @@ static inline void dma_buf_kunmap(struct dma_buf *dmabuf,
> unsigned long pnum, void *vaddr)
> {
> }
> +
> +static inline void *dma_buf_vmap(struct dma_buf *dmabuf)
> +{
> +}
> +
> +static inline void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> +{
> +}
> #endif /* CONFIG_DMA_SHARED_BUFFER */
>
> #endif /* __DMA_BUF_H__ */
> --
> 1.7.6
>
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