cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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videobuf-dma-sg.h (2856B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * helper functions for SG DMA video4linux capture buffers
      4 *
      5 * The functions expect the hardware being able to scatter gather
      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 *
     10 * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
     11 *
     12 * Highly based on video-buf written originally by:
     13 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
     14 * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
     15 * (c) 2006 Ted Walther and John Sokol
     16 */
     17#ifndef _VIDEOBUF_DMA_SG_H
     18#define _VIDEOBUF_DMA_SG_H
     19
     20#include <media/videobuf-core.h>
     21
     22/* --------------------------------------------------------------------- */
     23
     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_*()
     34 *	see Documentation/core-api/dma-api-howto.rst, these functions to
     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
     43struct videobuf_dmabuf {
     44	u32                 magic;
     45
     46	/* for userland buffer */
     47	int                 offset;
     48	size_t		    size;
     49	struct page         **pages;
     50
     51	/* for kernel buffers */
     52	void                *vaddr;
     53	struct page         **vaddr_pages;
     54	dma_addr_t          *dma_addr;
     55	struct device       *dev;
     56
     57	/* for overlay buffers (pci-pci dma) */
     58	dma_addr_t          bus_addr;
     59
     60	/* common */
     61	struct scatterlist  *sglist;
     62	int                 sglen;
     63	unsigned long       nr_pages;
     64	int                 direction;
     65};
     66
     67struct videobuf_dma_sg_memory {
     68	u32                 magic;
     69
     70	/* for mmap'ed buffers */
     71	struct videobuf_dmabuf  dma;
     72};
     73
     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 */
     84int videobuf_dma_free(struct videobuf_dmabuf *dma);
     85
     86int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma);
     87struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf);
     88
     89void *videobuf_sg_alloc(size_t size);
     90
     91void videobuf_queue_sg_init(struct videobuf_queue *q,
     92			 const struct videobuf_queue_ops *ops,
     93			 struct device *dev,
     94			 spinlock_t *irqlock,
     95			 enum v4l2_buf_type type,
     96			 enum v4l2_field field,
     97			 unsigned int msize,
     98			 void *priv,
     99			 struct mutex *ext_lock);
    100
    101#endif /* _VIDEOBUF_DMA_SG_H */
    102