1/* 2 * 3 * generic helper functions for video4linux capture buffers, to handle 4 * memory management and PCI DMA. 5 * Right now, bttv, saa7134, saa7146 and cx88 use it. 6 * 7 * The functions expect the hardware being able to scatter gatter 8 * (i.e. the buffers are not linear in physical memory, but fragmented 9 * into PAGE_SIZE chunks). They also assume the driver does not need 10 * to touch the video data. 11 * 12 * device specific map/unmap/sync stuff now are mapped as file operations 13 * to allow its usage by USB and virtual devices. 14 * 15 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> 16 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org> 17 * (c) 2006 Ted Walther and John Sokol 18 * 19 * This program is free software; you can redistribute it and/or modify 20 * it under the terms of the GNU General Public License as published by 21 * the Free Software Foundation; either version 2 of the License, or 22 * (at your option) any later version. 23 */ 24 25#include <linux/videodev2.h> 26#include <linux/poll.h> 27 28#define UNSET (-1U) 29 30/* --------------------------------------------------------------------- */ 31 32/* 33 * Return a scatterlist for some page-aligned vmalloc()'ed memory 34 * block (NULL on errors). Memory for the scatterlist is allocated 35 * using kmalloc. The caller must free the memory. 36 */ 37struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages); 38 39/* 40 * Return a scatterlist for a an array of userpages (NULL on errors). 41 * Memory for the scatterlist is allocated using kmalloc. The caller 42 * must free the memory. 43 */ 44struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages, 45 int offset); 46 47struct videobuf_buffer; 48struct videobuf_queue; 49 50/* --------------------------------------------------------------------- */ 51 52/* 53 * A small set of helper functions to manage buffers (both userland 54 * and kernel) for DMA. 55 * 56 * videobuf_dma_init_*() 57 * creates a buffer. The userland version takes a userspace 58 * pointer + length. The kernel version just wants the size and 59 * does memory allocation too using vmalloc_32(). 60 * 61 * videobuf_dma_*() 62 * see Documentation/DMA-mapping.txt, these functions to 63 * basically the same. The map function does also build a 64 * scatterlist for the buffer (and unmap frees it ...) 65 * 66 * videobuf_dma_free() 67 * no comment ... 68 * 69 */ 70 71struct videobuf_dmabuf { 72 u32 magic; 73 74 /* for userland buffer */ 75 int offset; 76 struct page **pages; 77 78 /* for kernel buffers */ 79 void *vmalloc; 80 81 /* Stores the userspace pointer to vmalloc area */ 82 void *varea; 83 84 /* for overlay buffers (pci-pci dma) */ 85 dma_addr_t bus_addr; 86 87 /* common */ 88 struct scatterlist *sglist; 89 int sglen; 90 int nr_pages; 91 int direction; 92}; 93 94void videobuf_dma_init(struct videobuf_dmabuf *dma); 95int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, 96 unsigned long data, unsigned long size); 97int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, 98 int nr_pages); 99int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, 100 dma_addr_t addr, int nr_pages); 101int videobuf_dma_free(struct videobuf_dmabuf *dma); 102 103int videobuf_dma_map(struct videobuf_queue* q,struct videobuf_dmabuf *dma); 104int videobuf_dma_sync(struct videobuf_queue* q,struct videobuf_dmabuf *dma); 105int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma); 106 107int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma); 108int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma); 109 110/* --------------------------------------------------------------------- */ 111 112/* 113 * A small set of helper functions to manage video4linux buffers. 114 * 115 * struct videobuf_buffer holds the data structures used by the helper 116 * functions, additionally some commonly used fields for v4l buffers 117 * (width, height, lists, waitqueue) are in there. That struct should 118 * be used as first element in the drivers buffer struct. 119 * 120 * about the mmap helpers (videobuf_mmap_*): 121 * 122 * The mmaper function allows to map any subset of contingous buffers. 123 * This includes one mmap() call for all buffers (which the original 124 * video4linux API uses) as well as one mmap() for every single buffer 125 * (which v4l2 uses). 126 * 127 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds 128 * userspace address + size which can be feeded into the 129 * videobuf_dma_init_user function listed above. 130 * 131 */ 132 133struct videobuf_mapping { 134 unsigned int count; 135 unsigned long start; 136 unsigned long end; 137 struct videobuf_queue *q; 138}; 139 140enum videobuf_state { 141 STATE_NEEDS_INIT = 0, 142 STATE_PREPARED = 1, 143 STATE_QUEUED = 2, 144 STATE_ACTIVE = 3, 145 STATE_DONE = 4, 146 STATE_ERROR = 5, 147 STATE_IDLE = 6, 148}; 149 150struct videobuf_buffer { 151 unsigned int i; 152 u32 magic; 153 154 /* info about the buffer */ 155 unsigned int width; 156 unsigned int height; 157 unsigned int bytesperline; /* use only if != 0 */ 158 unsigned long size; 159 unsigned int input; 160 enum v4l2_field field; 161 enum videobuf_state state; 162 struct videobuf_dmabuf dma; 163 struct list_head stream; /* QBUF/DQBUF list */ 164 165 /* for mmap'ed buffers */ 166 enum v4l2_memory memory; 167 size_t boff; /* buffer offset (mmap + overlay) */ 168 size_t bsize; /* buffer size */ 169 unsigned long baddr; /* buffer addr (userland ptr!) */ 170 struct videobuf_mapping *map; 171 172 /* touched by irq handler */ 173 struct list_head queue; 174 wait_queue_head_t done; 175 unsigned int field_count; 176 struct timeval ts; 177}; 178 179typedef int (vb_map_sg_t)(void *dev,struct scatterlist *sglist,int nr_pages, 180 int direction); 181 182 183struct videobuf_queue_ops { 184 int (*buf_setup)(struct videobuf_queue *q, 185 unsigned int *count, unsigned int *size); 186 int (*buf_prepare)(struct videobuf_queue *q, 187 struct videobuf_buffer *vb, 188 enum v4l2_field field); 189 void (*buf_queue)(struct videobuf_queue *q, 190 struct videobuf_buffer *vb); 191 void (*buf_release)(struct videobuf_queue *q, 192 struct videobuf_buffer *vb); 193 194 /* Helper operations - device dependent. 195 * If null, videobuf_init defaults all to PCI handling 196 */ 197 198 vb_map_sg_t *vb_map_sg; 199 vb_map_sg_t *vb_dma_sync_sg; 200 vb_map_sg_t *vb_unmap_sg; 201}; 202 203struct videobuf_queue { 204 struct mutex lock; 205 spinlock_t *irqlock; 206 void *dev; /* on pci, points to struct pci_dev */ 207 208 enum v4l2_buf_type type; 209 unsigned int inputs; /* for V4L2_BUF_FLAG_INPUT */ 210 unsigned int msize; 211 enum v4l2_field field; 212 enum v4l2_field last; /* for field=V4L2_FIELD_ALTERNATE */ 213 struct videobuf_buffer *bufs[VIDEO_MAX_FRAME]; 214 struct videobuf_queue_ops *ops; 215 216 /* capture via mmap() + ioctl(QBUF/DQBUF) */ 217 unsigned int streaming; 218 struct list_head stream; 219 220 /* capture via read() */ 221 unsigned int reading; 222 unsigned int read_off; 223 struct videobuf_buffer *read_buf; 224 225 /* driver private data */ 226 void *priv_data; 227}; 228 229void* videobuf_alloc(unsigned int size); 230int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr); 231int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb, 232 struct v4l2_framebuffer *fbuf); 233 234/* Maps fops to PCI stuff */ 235void videobuf_queue_pci(struct videobuf_queue* q); 236 237void videobuf_queue_init(struct videobuf_queue *q, 238 struct videobuf_queue_ops *ops, 239 void *dev, 240 spinlock_t *irqlock, 241 enum v4l2_buf_type type, 242 enum v4l2_field field, 243 unsigned int msize, 244 void *priv); 245int videobuf_queue_is_busy(struct videobuf_queue *q); 246void videobuf_queue_cancel(struct videobuf_queue *q); 247 248enum v4l2_field videobuf_next_field(struct videobuf_queue *q); 249void videobuf_status(struct v4l2_buffer *b, struct videobuf_buffer *vb, 250 enum v4l2_buf_type type); 251int videobuf_reqbufs(struct videobuf_queue *q, 252 struct v4l2_requestbuffers *req); 253int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b); 254int videobuf_qbuf(struct videobuf_queue *q, 255 struct v4l2_buffer *b); 256int videobuf_dqbuf(struct videobuf_queue *q, 257 struct v4l2_buffer *b, int nonblocking); 258int videobuf_streamon(struct videobuf_queue *q); 259int videobuf_streamoff(struct videobuf_queue *q); 260 261int videobuf_read_start(struct videobuf_queue *q); 262void videobuf_read_stop(struct videobuf_queue *q); 263ssize_t videobuf_read_stream(struct videobuf_queue *q, 264 char __user *data, size_t count, loff_t *ppos, 265 int vbihack, int nonblocking); 266ssize_t videobuf_read_one(struct videobuf_queue *q, 267 char __user *data, size_t count, loff_t *ppos, 268 int nonblocking); 269unsigned int videobuf_poll_stream(struct file *file, 270 struct videobuf_queue *q, 271 poll_table *wait); 272 273int videobuf_mmap_setup(struct videobuf_queue *q, 274 unsigned int bcount, unsigned int bsize, 275 enum v4l2_memory memory); 276int videobuf_mmap_free(struct videobuf_queue *q); 277int videobuf_mmap_mapper(struct videobuf_queue *q, 278 struct vm_area_struct *vma); 279 280/* --------------------------------------------------------------------- */ 281 282/* 283 * Local variables: 284 * c-basic-offset: 8 285 * End: 286 */ 287