From: Dave Airlie airlied@redhat.com
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.
Signed-off-by: Dave Airlie airlied@redhat.com --- 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..750f92c 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(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(dma_buf_vunmap); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 3efbfc2..b92b6de 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 *) +{ +} + +static inline void dma_buf_vunmap(struct dma_buf *, void *vaddr); +{ +} #endif /* CONFIG_DMA_SHARED_BUFFER */
#endif /* __DMA_BUF_H__ */