[linux-block.git] / include / media / videobuf-dma-sg.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * helper functions for SG DMA video4linux capture buffers
 *
 * The functions expect the hardware being able to scatter gather
 * (i.e. the buffers are not linear in physical memory, but fragmented
 * into PAGE_SIZE chunks).  They also assume the driver does not need
 * to touch the video data.
 *
 * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
 *
 * Highly based on video-buf written originally by:
 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
 * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
 * (c) 2006 Ted Walther and John Sokol
 */
#ifndef _VIDEOBUF_DMA_SG_H
#define _VIDEOBUF_DMA_SG_H

#include <media/videobuf-core.h>

/* --------------------------------------------------------------------- */

/*
 * A small set of helper functions to manage buffers (both userland
 * and kernel) for DMA.
 *
 * videobuf_dma_init_*()
 *	creates a buffer.  The userland version takes a userspace
 *	pointer + length.  The kernel version just wants the size and
 *	does memory allocation too using vmalloc_32().
 *
 * videobuf_dma_*()
 *	see Documentation/core-api/dma-api-howto.rst, these functions to
 *	basically the same.  The map function does also build a
 *	scatterlist for the buffer (and unmap frees it ...)
 *
 * videobuf_dma_free()
 *	no comment ...
 *
 */

struct videobuf_dmabuf {
	u32                 magic;

	/* for userland buffer */
	int                 offset;
	size_t		    size;
	struct page         **pages;

	/* for kernel buffers */
	void                *vaddr;
	struct page         **vaddr_pages;
	dma_addr_t          *dma_addr;
	struct device       *dev;

	/* for overlay buffers (pci-pci dma) */
	dma_addr_t          bus_addr;

	/* common */
	struct scatterlist  *sglist;
	int                 sglen;
	unsigned long       nr_pages;
	int                 direction;
};

struct videobuf_dma_sg_memory {
	u32                 magic;

	/* for mmap'ed buffers */
	struct videobuf_dmabuf  dma;
};

/*
 * Scatter-gather DMA buffer API.
 *
 * These functions provide a simple way to create a page list and a
 * scatter-gather list from a kernel, userspace of physical address and map the
 * memory for DMA operation.
 *
 * Despite the name, this is totally unrelated to videobuf, except that
 * videobuf-dma-sg uses the same API internally.
 */
int videobuf_dma_free(struct videobuf_dmabuf *dma);

int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);
struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf);

void *videobuf_sg_alloc(size_t size);

void videobuf_queue_sg_init(struct videobuf_queue *q,
			 const struct videobuf_queue_ops *ops,
			 struct device *dev,
			 spinlock_t *irqlock,
			 enum v4l2_buf_type type,
			 enum v4l2_field field,
			 unsigned int msize,
			 void *priv,
			 struct mutex *ext_lock);

#endif /* _VIDEOBUF_DMA_SG_H */
Commit	Line	Data
77512baa	1	/* SPDX-License-Identifier: GPL-2.0-only */
7a7d9a89	2	/*
0705135e	3	* helper functions for SG DMA video4linux capture buffers
7a7d9a89	4	*
5d6aaf50	5	* The functions expect the hardware being able to scatter gather
7a7d9a89 MCC	6	* (i.e. the buffers are not linear in physical memory, but fragmented
	7	* into PAGE_SIZE chunks). They also assume the driver does not need
	8	* to touch the video data.
	9	*
32590819	10	* (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
7a7d9a89 MCC	11	*
	12	* Highly based on video-buf written originally by:
	13	* (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
32590819	14	* (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
7a7d9a89	15	* (c) 2006 Ted Walther and John Sokol
7a7d9a89	16	*/
7a02264c PO	17	#ifndef _VIDEOBUF_DMA_SG_H
7a02264c PO	18	#define _VIDEOBUF_DMA_SG_H
7a7d9a89 MCC	19
	20	#include <media/videobuf-core.h>
	21
	22	/* --------------------------------------------------------------------- */
	23
7a7d9a89 MCC	24	/*
	25	* A small set of helper functions to manage buffers (both userland
	26	* and kernel) for DMA.
	27	*
	28	* videobuf_dma_init_*()
	29	* creates a buffer. The userland version takes a userspace
	30	* pointer + length. The kernel version just wants the size and
	31	* does memory allocation too using vmalloc_32().
	32	*
	33	* videobuf_dma_*()
985098a0	34	* see Documentation/core-api/dma-api-howto.rst, these functions to
7a7d9a89 MCC	35	* basically the same. The map function does also build a
	36	* scatterlist for the buffer (and unmap frees it ...)
	37	*
	38	* videobuf_dma_free()
	39	* no comment ...
	40	*
	41	*/
	42
	43	struct videobuf_dmabuf {
	44	u32 magic;
	45
	46	/* for userland buffer */
	47	int offset;
2fc11536	48	size_t size;
7a7d9a89 MCC	49	struct page **pages;
	50
	51	/* for kernel buffers */
bb6dbe74	52	void *vaddr;
7b4eeed1 JH	53	struct page **vaddr_pages;
	54	dma_addr_t *dma_addr;
	55	struct device *dev;
7a7d9a89	56
7a7d9a89 MCC	57	/* for overlay buffers (pci-pci dma) */
	58	dma_addr_t bus_addr;
	59
	60	/* common */
	61	struct scatterlist *sglist;
	62	int sglen;
1faa39e0	63	unsigned long nr_pages;
7a7d9a89 MCC	64	int direction;
	65	};
	66
7a02264c	67	struct videobuf_dma_sg_memory {
7a7d9a89 MCC	68	u32 magic;
	69
	70	/* for mmap'ed buffers */
7a7d9a89 MCC	71	struct videobuf_dmabuf dma;
	72	};
	73
95268403 LP	74	/*
	75	* Scatter-gather DMA buffer API.
	76	*
	77	* These functions provide a simple way to create a page list and a
	78	* scatter-gather list from a kernel, userspace of physical address and map the
	79	* memory for DMA operation.
	80	*
	81	* Despite the name, this is totally unrelated to videobuf, except that
	82	* videobuf-dma-sg uses the same API internally.
	83	*/
7a7d9a89 MCC	84	int videobuf_dma_free(struct videobuf_dmabuf *dma);
7a7d9a89 MCC	85
95268403	86	int videobuf_dma_unmap(struct device dev, struct videobuf_dmabuf dma);
7a02264c	87	struct videobuf_dmabuf videobuf_to_dma(struct videobuf_buffer buf);
7a7d9a89	88
0705135e	89	void *videobuf_sg_alloc(size_t size);
7a7d9a89	90
7a02264c	91	void videobuf_queue_sg_init(struct videobuf_queue *q,
38a54f35	92	const struct videobuf_queue_ops *ops,
0705135e	93	struct device *dev,
7a7d9a89 MCC	94	spinlock_t *irqlock,
	95	enum v4l2_buf_type type,
	96	enum v4l2_field field,
	97	unsigned int msize,
08bff03e HV	98	void *priv,
08bff03e HV	99	struct mutex *ext_lock);
7a7d9a89	100
7a02264c PO	101	#endif /* _VIDEOBUF_DMA_SG_H */
7a02264c PO	102