| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 1 | /* |
| 2 | * helper functions for SG DMA video4linux capture buffers |
| 3 | * |
| 4 | * The functions expect the hardware being able to scatter gather |
| 5 | * (i.e. the buffers are not linear in physical memory, but fragmented |
| 6 | * into PAGE_SIZE chunks). They also assume the driver does not need |
| 7 | * to touch the video data. |
| 8 | * |
| 9 | * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org> |
| 10 | * |
| 11 | * Highly based on video-buf written originally by: |
| 12 | * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> |
| 13 | * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org> |
| 14 | * (c) 2006 Ted Walther and John Sokol |
| 15 | * |
| 16 | * This program is free software; you can redistribute it and/or modify |
| 17 | * it under the terms of the GNU General Public License as published by |
| 18 | * the Free Software Foundation; either version 2 |
| 19 | */ |
| 20 | #ifndef _VIDEOBUF_DMA_SG_H |
| 21 | #define _VIDEOBUF_DMA_SG_H |
| 22 | |
| 23 | #include <media/videobuf-core.h> |
| 24 | |
| 25 | /* --------------------------------------------------------------------- */ |
| 26 | |
| 27 | /* |
| 28 | * A small set of helper functions to manage buffers (both userland |
| 29 | * and kernel) for DMA. |
| 30 | * |
| 31 | * videobuf_dma_init_*() |
| 32 | * creates a buffer. The userland version takes a userspace |
| 33 | * pointer + length. The kernel version just wants the size and |
| 34 | * does memory allocation too using vmalloc_32(). |
| 35 | * |
| 36 | * videobuf_dma_*() |
| 37 | * see Documentation/DMA-API-HOWTO.txt, these functions to |
| 38 | * basically the same. The map function does also build a |
| 39 | * scatterlist for the buffer (and unmap frees it ...) |
| 40 | * |
| 41 | * videobuf_dma_free() |
| 42 | * no comment ... |
| 43 | * |
| 44 | */ |
| 45 | |
| 46 | struct videobuf_dmabuf { |
| 47 | u32 magic; |
| 48 | |
| 49 | /* for userland buffer */ |
| 50 | int offset; |
| 51 | size_t size; |
| 52 | struct page **pages; |
| 53 | |
| 54 | /* for kernel buffers */ |
| 55 | void *vaddr; |
| 56 | struct page **vaddr_pages; |
| 57 | dma_addr_t *dma_addr; |
| 58 | struct device *dev; |
| 59 | |
| 60 | /* for overlay buffers (pci-pci dma) */ |
| 61 | dma_addr_t bus_addr; |
| 62 | |
| 63 | /* common */ |
| 64 | struct scatterlist *sglist; |
| 65 | int sglen; |
| 66 | int nr_pages; |
| 67 | int direction; |
| 68 | }; |
| 69 | |
| 70 | struct videobuf_dma_sg_memory { |
| 71 | u32 magic; |
| 72 | |
| 73 | /* for mmap'ed buffers */ |
| 74 | struct videobuf_dmabuf dma; |
| 75 | }; |
| 76 | |
| 77 | /* |
| 78 | * Scatter-gather DMA buffer API. |
| 79 | * |
| 80 | * These functions provide a simple way to create a page list and a |
| 81 | * scatter-gather list from a kernel, userspace of physical address and map the |
| 82 | * memory for DMA operation. |
| 83 | * |
| 84 | * Despite the name, this is totally unrelated to videobuf, except that |
| 85 | * videobuf-dma-sg uses the same API internally. |
| 86 | */ |
| 87 | int videobuf_dma_free(struct videobuf_dmabuf *dma); |
| 88 | |
| 89 | int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma); |
| 90 | struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf); |
| 91 | |
| 92 | void *videobuf_sg_alloc(size_t size); |
| 93 | |
| 94 | void videobuf_queue_sg_init(struct videobuf_queue *q, |
| 95 | const struct videobuf_queue_ops *ops, |
| 96 | struct device *dev, |
| 97 | spinlock_t *irqlock, |
| 98 | enum v4l2_buf_type type, |
| 99 | enum v4l2_field field, |
| 100 | unsigned int msize, |
| 101 | void *priv, |
| 102 | struct mutex *ext_lock); |
| 103 | |
| 104 | #endif /* _VIDEOBUF_DMA_SG_H */ |
| 105 | |