/* * helper functions for SG DMA video4linux capture buffers * * The functions expect the hardware being able to scatter gatter * (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@infradead.org> * * Highly based on video-buf written originally by: * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org> * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org> * (c) 2006 Ted Walther and John Sokol * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 */ #include <linux/init.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/dma-mapping.h> #include <linux/vmalloc.h> #include <linux/pagemap.h> #include <linux/scatterlist.h> #include <asm/page.h> #include <asm/pgtable.h> #include <media/videobuf-dma-sg.h> #define MAGIC_DMABUF 0x19721112 #define MAGIC_SG_MEM 0x17890714 #define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \ { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); } static int debug; module_param(debug, int, 0644); MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers"); MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>"); MODULE_LICENSE("GPL"); #define dprintk(level, fmt, arg...) if (debug >= level) \ printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg) /* --------------------------------------------------------------------- */ struct scatterlist* videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages) { struct scatterlist *sglist; struct page *pg; int i; sglist = kcalloc(nr_pages, sizeof(struct scatterlist), GFP_KERNEL); if (NULL == sglist) return NULL; sg_init_table(sglist, nr_pages); for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) { pg = vmalloc_to_page(virt); if (NULL == pg) goto err; BUG_ON(PageHighMem(pg)); sg_set_page(&sglist[i], pg, PAGE_SIZE, 0); } return sglist; err: kfree(sglist); return NULL; } struct scatterlist* videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset) { struct scatterlist *sglist; int i = 0; if (NULL == pages[0]) return NULL; sglist = kcalloc(nr_pages, sizeof(*sglist), GFP_KERNEL); if (NULL == sglist) return NULL; sg_init_table(sglist, nr_pages); if (NULL == pages[0]) goto nopage; if (PageHighMem(pages[0])) /* DMA to highmem pages might not work */ goto highmem; sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset); for (i = 1; i < nr_pages; i++) { if (NULL == pages[i]) goto nopage; if (PageHighMem(pages[i])) goto highmem; sg_set_page(&sglist[i], pages[i], PAGE_SIZE, 0); } return sglist; nopage: dprintk(2,"sgl: oops - no page\n"); kfree(sglist); return NULL; highmem: dprintk(2,"sgl: oops - highmem page\n"); kfree(sglist); return NULL; } /* --------------------------------------------------------------------- */ struct videobuf_dmabuf *videobuf_to_dma (struct videobuf_buffer *buf) { struct videobuf_dma_sg_memory *mem = buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); return &mem->dma; } void videobuf_dma_init(struct videobuf_dmabuf *dma) { memset(dma,0,sizeof(*dma)); dma->magic = MAGIC_DMABUF; } static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, int direction, unsigned long data, unsigned long size) { unsigned long first,last; int err, rw = 0; dma->direction = direction; switch (dma->direction) { case DMA_FROM_DEVICE: rw = READ; break; case DMA_TO_DEVICE: rw = WRITE; break; default: BUG(); } first = (data & PAGE_MASK) >> PAGE_SHIFT; last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT; dma->offset = data & ~PAGE_MASK; dma->nr_pages = last-first+1; dma->pages = kmalloc(dma->nr_pages * sizeof(struct page*), GFP_KERNEL); if (NULL == dma->pages) return -ENOMEM; dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n", data,size,dma->nr_pages); dma->varea = (void *) data; err = get_user_pages(current,current->mm, data & PAGE_MASK, dma->nr_pages, rw == READ, 1, /* force */ dma->pages, NULL); if (err != dma->nr_pages) { dma->nr_pages = (err >= 0) ? err : 0; dprintk(1,"get_user_pages: err=%d [%d]\n",err,dma->nr_pages); return err < 0 ? err : -EINVAL; } return 0; } int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction, unsigned long data, unsigned long size) { int ret; down_read(¤t->mm->mmap_sem); ret = videobuf_dma_init_user_locked(dma, direction, data, size); up_read(¤t->mm->mmap_sem); return ret; } int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction, int nr_pages) { dprintk(1,"init kernel [%d pages]\n",nr_pages); dma->direction = direction; dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT); if (NULL == dma->vmalloc) { dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages); return -ENOMEM; } dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n", (unsigned long)dma->vmalloc, nr_pages << PAGE_SHIFT); memset(dma->vmalloc,0,nr_pages << PAGE_SHIFT); dma->nr_pages = nr_pages; return 0; } int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction, dma_addr_t addr, int nr_pages) { dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n", nr_pages,(unsigned long)addr); dma->direction = direction; if (0 == addr) return -EINVAL; dma->bus_addr = addr; dma->nr_pages = nr_pages; return 0; } int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma) { MAGIC_CHECK(dma->magic,MAGIC_DMABUF); BUG_ON(0 == dma->nr_pages); if (dma->pages) { dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages, dma->offset); } if (dma->vmalloc) { dma->sglist = videobuf_vmalloc_to_sg (dma->vmalloc,dma->nr_pages); } if (dma->bus_addr) { dma->sglist = kmalloc(sizeof(struct scatterlist), GFP_KERNEL); if (NULL != dma->sglist) { dma->sglen = 1; sg_dma_address(&dma->sglist[0]) = dma->bus_addr & PAGE_MASK; dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK; sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE; } } if (NULL == dma->sglist) { dprintk(1,"scatterlist is NULL\n"); return -ENOMEM; } if (!dma->bus_addr) { dma->sglen = dma_map_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction); if (0 == dma->sglen) { printk(KERN_WARNING "%s: videobuf_map_sg failed\n",__func__); kfree(dma->sglist); dma->sglist = NULL; dma->sglen = 0; return -EIO; } } return 0; } int videobuf_dma_sync(struct videobuf_queue *q, struct videobuf_dmabuf *dma) { MAGIC_CHECK(dma->magic, MAGIC_DMABUF); BUG_ON(!dma->sglen); dma_sync_sg_for_cpu(q->dev, dma->sglist, dma->nr_pages, dma->direction); return 0; } int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma) { MAGIC_CHECK(dma->magic, MAGIC_DMABUF); if (!dma->sglen) return 0; dma_unmap_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction); kfree(dma->sglist); dma->sglist = NULL; dma->sglen = 0; return 0; } int videobuf_dma_free(struct videobuf_dmabuf *dma) { MAGIC_CHECK(dma->magic,MAGIC_DMABUF); BUG_ON(dma->sglen); if (dma->pages) { int i; for (i=0; i < dma->nr_pages; i++) page_cache_release(dma->pages[i]); kfree(dma->pages); dma->pages = NULL; } vfree(dma->vmalloc); dma->vmalloc = NULL; dma->varea = NULL; if (dma->bus_addr) { dma->bus_addr = 0; } dma->direction = DMA_NONE; return 0; } /* --------------------------------------------------------------------- */ int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma) { struct videobuf_queue q; q.dev = dev; return videobuf_dma_map(&q, dma); } int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) { struct videobuf_queue q; q.dev = dev; return videobuf_dma_unmap(&q, dma); } /* --------------------------------------------------------------------- */ static void videobuf_vm_open(struct vm_area_struct *vma) { struct videobuf_mapping *map = vma->vm_private_data; dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map, map->count,vma->vm_start,vma->vm_end); map->count++; } static void videobuf_vm_close(struct vm_area_struct *vma) { struct videobuf_mapping *map = vma->vm_private_data; struct videobuf_queue *q = map->q; struct videobuf_dma_sg_memory *mem; int i; dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map, map->count,vma->vm_start,vma->vm_end); map->count--; if (0 == map->count) { dprintk(1,"munmap %p q=%p\n",map,q); mutex_lock(&q->vb_lock); for (i = 0; i < VIDEO_MAX_FRAME; i++) { if (NULL == q->bufs[i]) continue; mem=q->bufs[i]->priv; if (!mem) continue; MAGIC_CHECK(mem->magic,MAGIC_SG_MEM); if (q->bufs[i]->map != map) continue; q->bufs[i]->map = NULL; q->bufs[i]->baddr = 0; q->ops->buf_release(q,q->bufs[i]); } mutex_unlock(&q->vb_lock); kfree(map); } return; } /* * Get a anonymous page for the mapping. Make sure we can DMA to that * memory location with 32bit PCI devices (i.e. don't use highmem for * now ...). Bounce buffers don't work very well for the data rates * video capture has. */ static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct page *page; dprintk(3,"fault: fault @ %08lx [vma %08lx-%08lx]\n", (unsigned long)vmf->virtual_address,vma->vm_start,vma->vm_end); page = alloc_page(GFP_USER | __GFP_DMA32); if (!page) return VM_FAULT_OOM; clear_user_page(page_address(page), (unsigned long)vmf->virtual_address, page); vmf->page = page; return 0; } static struct vm_operations_struct videobuf_vm_ops = { .open = videobuf_vm_open, .close = videobuf_vm_close, .fault = videobuf_vm_fault, }; /* --------------------------------------------------------------------- * SG handlers for the generic methods */ /* Allocated area consists on 3 parts: struct video_buffer struct <driver>_buffer (cx88_buffer, saa7134_buf, ...) struct videobuf_dma_sg_memory */ static void *__videobuf_alloc(size_t size) { struct videobuf_dma_sg_memory *mem; struct videobuf_buffer *vb; vb = kzalloc(size+sizeof(*mem),GFP_KERNEL); mem = vb->priv = ((char *)vb)+size; mem->magic=MAGIC_SG_MEM; videobuf_dma_init(&mem->dma); dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n", __func__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb), mem,(long)sizeof(*mem)); return vb; } static int __videobuf_iolock (struct videobuf_queue* q, struct videobuf_buffer *vb, struct v4l2_framebuffer *fbuf) { int err,pages; dma_addr_t bus; struct videobuf_dma_sg_memory *mem = vb->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); switch (vb->memory) { case V4L2_MEMORY_MMAP: case V4L2_MEMORY_USERPTR: if (0 == vb->baddr) { /* no userspace addr -- kernel bounce buffer */ pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; err = videobuf_dma_init_kernel( &mem->dma, DMA_FROM_DEVICE, pages ); if (0 != err) return err; } else if (vb->memory == V4L2_MEMORY_USERPTR) { /* dma directly to userspace */ err = videobuf_dma_init_user( &mem->dma, DMA_FROM_DEVICE, vb->baddr,vb->bsize ); if (0 != err) return err; } else { /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP buffers can only be called from videobuf_qbuf we take current->mm->mmap_sem there, to prevent locking inversion, so don't take it here */ err = videobuf_dma_init_user_locked(&mem->dma, DMA_FROM_DEVICE, vb->baddr, vb->bsize); if (0 != err) return err; } break; case V4L2_MEMORY_OVERLAY: if (NULL == fbuf) return -EINVAL; /* FIXME: need sanity checks for vb->boff */ /* * Using a double cast to avoid compiler warnings when * building for PAE. Compiler doesn't like direct casting * of a 32 bit ptr to 64 bit integer. */ bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff; pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT; err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE, bus, pages); if (0 != err) return err; break; default: BUG(); } err = videobuf_dma_map(q, &mem->dma); if (0 != err) return err; return 0; } static int __videobuf_sync(struct videobuf_queue *q, struct videobuf_buffer *buf) { struct videobuf_dma_sg_memory *mem = buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic,MAGIC_SG_MEM); return videobuf_dma_sync(q,&mem->dma); } static int __videobuf_mmap_free(struct videobuf_queue *q) { int i; for (i = 0; i < VIDEO_MAX_FRAME; i++) { if (q->bufs[i]) { if (q->bufs[i]->map) return -EBUSY; } } return 0; } static int __videobuf_mmap_mapper(struct videobuf_queue *q, struct vm_area_struct *vma) { struct videobuf_dma_sg_memory *mem; struct videobuf_mapping *map; unsigned int first,last,size,i; int retval; retval = -EINVAL; if (!(vma->vm_flags & VM_WRITE)) { dprintk(1,"mmap app bug: PROT_WRITE please\n"); goto done; } if (!(vma->vm_flags & VM_SHARED)) { dprintk(1,"mmap app bug: MAP_SHARED please\n"); goto done; } /* This function maintains backwards compatibility with V4L1 and will * map more than one buffer if the vma length is equal to the combined * size of multiple buffers than it will map them together. See * VIDIOCGMBUF in the v4l spec * * TODO: Allow drivers to specify if they support this mode */ /* look for first buffer to map */ for (first = 0; first < VIDEO_MAX_FRAME; first++) { if (NULL == q->bufs[first]) continue; mem=q->bufs[first]->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic,MAGIC_SG_MEM); if (V4L2_MEMORY_MMAP != q->bufs[first]->memory) continue; if (q->bufs[first]->boff == (vma->vm_pgoff << PAGE_SHIFT)) break; } if (VIDEO_MAX_FRAME == first) { dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n", (vma->vm_pgoff << PAGE_SHIFT)); goto done; } /* look for last buffer to map */ for (size = 0, last = first; last < VIDEO_MAX_FRAME; last++) { if (NULL == q->bufs[last]) continue; if (V4L2_MEMORY_MMAP != q->bufs[last]->memory) continue; if (q->bufs[last]->map) { retval = -EBUSY; goto done; } size += q->bufs[last]->bsize; if (size == (vma->vm_end - vma->vm_start)) break; } if (VIDEO_MAX_FRAME == last) { dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n", (vma->vm_end - vma->vm_start)); goto done; } /* create mapping + update buffer list */ retval = -ENOMEM; map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL); if (NULL == map) goto done; size = 0; for (i = first; i <= last; i++) { if (NULL == q->bufs[i]) continue; q->bufs[i]->map = map; q->bufs[i]->baddr = vma->vm_start + size; size += q->bufs[i]->bsize; } map->count = 1; map->start = vma->vm_start; map->end = vma->vm_end; map->q = q; vma->vm_ops = &videobuf_vm_ops; vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED; vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */ vma->vm_private_data = map; dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n", map,q,vma->vm_start,vma->vm_end,vma->vm_pgoff,first,last); retval = 0; done: return retval; } static int __videobuf_copy_to_user ( struct videobuf_queue *q, char __user *data, size_t count, int nonblocking ) { struct videobuf_dma_sg_memory *mem = q->read_buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic,MAGIC_SG_MEM); /* copy to userspace */ if (count > q->read_buf->size - q->read_off) count = q->read_buf->size - q->read_off; if (copy_to_user(data, mem->dma.vmalloc+q->read_off, count)) return -EFAULT; return count; } static int __videobuf_copy_stream ( struct videobuf_queue *q, char __user *data, size_t count, size_t pos, int vbihack, int nonblocking ) { unsigned int *fc; struct videobuf_dma_sg_memory *mem = q->read_buf->priv; BUG_ON(!mem); MAGIC_CHECK(mem->magic,MAGIC_SG_MEM); if (vbihack) { /* dirty, undocumented hack -- pass the frame counter * within the last four bytes of each vbi data block. * We need that one to maintain backward compatibility * to all vbi decoding software out there ... */ fc = (unsigned int*)mem->dma.vmalloc; fc += (q->read_buf->size>>2) -1; *fc = q->read_buf->field_count >> 1; dprintk(1,"vbihack: %d\n",*fc); } /* copy stuff using the common method */ count = __videobuf_copy_to_user (q,data,count,nonblocking); if ( (count==-EFAULT) && (0 == pos) ) return -EFAULT; return count; } static struct videobuf_qtype_ops sg_ops = { .magic = MAGIC_QTYPE_OPS, .alloc = __videobuf_alloc, .iolock = __videobuf_iolock, .sync = __videobuf_sync, .mmap_free = __videobuf_mmap_free, .mmap_mapper = __videobuf_mmap_mapper, .video_copy_to_user = __videobuf_copy_to_user, .copy_stream = __videobuf_copy_stream, }; void *videobuf_sg_alloc(size_t size) { struct videobuf_queue q; /* Required to make generic handler to call __videobuf_alloc */ q.int_ops = &sg_ops; q.msize = size; return videobuf_alloc(&q); } void videobuf_queue_sg_init(struct videobuf_queue* q, 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) { videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, priv, &sg_ops); } /* --------------------------------------------------------------------- */ EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg); EXPORT_SYMBOL_GPL(videobuf_to_dma); EXPORT_SYMBOL_GPL(videobuf_dma_init); EXPORT_SYMBOL_GPL(videobuf_dma_init_user); EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel); EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay); EXPORT_SYMBOL_GPL(videobuf_dma_map); EXPORT_SYMBOL_GPL(videobuf_dma_sync); EXPORT_SYMBOL_GPL(videobuf_dma_unmap); EXPORT_SYMBOL_GPL(videobuf_dma_free); EXPORT_SYMBOL_GPL(videobuf_sg_dma_map); EXPORT_SYMBOL_GPL(videobuf_sg_dma_unmap); EXPORT_SYMBOL_GPL(videobuf_sg_alloc); EXPORT_SYMBOL_GPL(videobuf_queue_sg_init); /* * Local variables: * c-basic-offset: 8 * End: */