From 01fd30da0474d5528d96a154cb50ce3b0352fd19 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 25 Sep 2020 13:55:58 +0200 Subject: dma-buf: Add struct dma-buf-map for storing struct dma_buf.vaddr_ptr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The new type struct dma_buf_map represents a mapping of dma-buf memory into kernel space. It contains a flag, is_iomem, that signals users to access the mapped memory with I/O operations instead of regular loads and stores. It was assumed that DMA buffer memory can be accessed with regular load and store operations. Some architectures, such as sparc64, require the use of I/O operations to access dma-map buffers that are located in I/O memory. Providing struct dma_buf_map allows drivers to implement this. This was specifically a problem when refreshing the graphics framebuffer on such systems. [1] As the first step, struct dma_buf stores an instance of struct dma_buf_map internally. Afterwards, dma-buf's vmap and vunmap interfaces are be converted. Finally, affected drivers can be fixed. v3: * moved documentation into separate patch * test for NULL pointers with ! [1] https://lore.kernel.org/dri-devel/20200725191012.GA434957@ravnborg.org/ Signed-off-by: Thomas Zimmermann Reviewed-by: Christian König Reviewed-by: Daniel Vetter Acked-by: Sumit Semwal Acked-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-2-tzimmermann@suse.de --- include/linux/dma-buf.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/dma-buf.h') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 957b398d30e5..fcc2ddfb6d18 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -13,6 +13,7 @@ #ifndef __DMA_BUF_H__ #define __DMA_BUF_H__ +#include #include #include #include @@ -309,7 +310,7 @@ struct dma_buf { const struct dma_buf_ops *ops; struct mutex lock; unsigned vmapping_counter; - void *vmap_ptr; + struct dma_buf_map vmap_ptr; const char *exp_name; const char *name; spinlock_t name_lock; -- cgit From 6619ccf1bb1d0ebb071f758111efa83918b216fc Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 25 Sep 2020 13:55:59 +0200 Subject: dma-buf: Use struct dma_buf_map in dma_buf_vmap() interfaces MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch updates dma_buf_vmap() and dma-buf's vmap callback to use struct dma_buf_map. The interfaces used to return a buffer address. This address now gets stored in an instance of the structure that is given as an additional argument. The functions return an errno code on errors. Users of the functions are updated accordingly. This is only an interface change. It is currently expected that dma-buf memory can be accessed with system memory load/store operations. v3: * update fastrpc driver (kernel test robot) v2: * always clear map parameter in dma_buf_vmap() (Daniel) * include dma-buf-heaps and i915 selftests (kernel test robot) Signed-off-by: Thomas Zimmermann Acked-by: Sumit Semwal Acked-by: Christian König Acked-by: Daniel Vetter Acked-by: Tomasz Figa Acked-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-3-tzimmermann@suse.de --- include/linux/dma-buf.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/dma-buf.h') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index fcc2ddfb6d18..7237997cfa38 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -266,7 +266,7 @@ struct dma_buf_ops { */ int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); - void *(*vmap)(struct dma_buf *); + int (*vmap)(struct dma_buf *dmabuf, struct dma_buf_map *map); void (*vunmap)(struct dma_buf *, void *vaddr); }; @@ -503,6 +503,6 @@ int dma_buf_end_cpu_access(struct dma_buf *dma_buf, 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); +int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map); +void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr); #endif /* __DMA_BUF_H__ */ -- cgit From 20e76f1a70596590dec32a5d1f598fba04859526 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 25 Sep 2020 13:56:00 +0200 Subject: dma-buf: Use struct dma_buf_map in dma_buf_vunmap() interfaces MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch updates dma_buf_vunmap() and dma-buf's vunmap callback to use struct dma_buf_map. The interfaces used to receive a buffer address. This address is now given in an instance of the structure. Users of the functions are updated accordingly. This is only an interface change. It is currently expected that dma-buf memory can be accessed with system memory load/store operations. v2: * include dma-buf-heaps and i915 selftests (kernel test robot) * initialize cma_obj before using it in drm_gem_cma_free_object() (kernel test robot) Signed-off-by: Thomas Zimmermann Acked-by: Sumit Semwal Acked-by: Christian König Acked-by: Daniel Vetter Acked-by: Tomasz Figa Acked-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20200925115601.23955-4-tzimmermann@suse.de --- include/linux/dma-buf.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/dma-buf.h') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 7237997cfa38..cf77cc15f4ba 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -267,7 +267,7 @@ struct dma_buf_ops { int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); int (*vmap)(struct dma_buf *dmabuf, struct dma_buf_map *map); - void (*vunmap)(struct dma_buf *, void *vaddr); + void (*vunmap)(struct dma_buf *dmabuf, struct dma_buf_map *map); }; /** @@ -504,5 +504,5 @@ int dma_buf_end_cpu_access(struct dma_buf *dma_buf, int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, unsigned long); int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map); -void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr); +void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map); #endif /* __DMA_BUF_H__ */ -- cgit From ac80cd17a615e472e3dcff0a5446a58540e64e6d Mon Sep 17 00:00:00 2001 From: Jianxin Xiong Date: Wed, 14 Oct 2020 09:16:01 -0700 Subject: dma-buf: Clarify that dma-buf sg lists are page aligned MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The dma-buf API have been used under the assumption that the sg lists returned from dma_buf_map_attachment() are fully page aligned. Lots of stuff can break otherwise all over the place. Clarify this in the documentation and add a check when DMA API debug is enabled. Signed-off-by: Jianxin Xiong Reviewed-by: Christian König Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/1602692161-107096-1-git-send-email-jianxin.xiong@intel.com --- include/linux/dma-buf.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/dma-buf.h') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index cf77cc15f4ba..03875eaed51a 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -146,7 +146,8 @@ struct dma_buf_ops { * * A &sg_table scatter list of or the backing storage of the DMA buffer, * already mapped into the device address space of the &device attached - * with the provided &dma_buf_attachment. + * with the provided &dma_buf_attachment. The addresses and lengths in + * the scatter list are PAGE_SIZE aligned. * * On failure, returns a negative error value wrapped into a pointer. * May also return -EINTR when a signal was received while being -- cgit From 476b485be03c37212fcf10d85510aae5d34316ef Mon Sep 17 00:00:00 2001 From: Jianxin Xiong Date: Tue, 10 Nov 2020 13:41:17 -0800 Subject: dma-buf: Document that dma-buf size is fixed The fact that the size of dma-buf is invariant over the lifetime of the buffer is mentioned in the comment of 'dma_buf_ops.mmap', but is not documented at where the info is defined. Add the missing documentation. Signed-off-by: Jianxin Xiong Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/1605044477-51833-7-git-send-email-jianxin.xiong@intel.com --- include/linux/dma-buf.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/dma-buf.h') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 03875eaed51a..cf72699cb2bc 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -273,7 +273,7 @@ struct dma_buf_ops { /** * struct dma_buf - shared buffer object - * @size: size of the buffer + * @size: size of the buffer; invariant over the lifetime of the buffer. * @file: file pointer used for sharing buffers across, and for refcounting. * @attachments: list of dma_buf_attachment that denotes all devices attached, * protected by dma_resv lock. @@ -405,7 +405,7 @@ struct dma_buf_attachment { * @exp_name: name of the exporter - useful for debugging. * @owner: pointer to exporter module - used for refcounting kernel module * @ops: Attach allocator-defined dma buf ops to the new buffer - * @size: Size of the buffer + * @size: Size of the buffer - invariant over the lifetime of the buffer * @flags: mode flags for the file * @resv: reservation-object, NULL to allocate default one * @priv: Attach private data of allocator to this buffer -- cgit