/* * 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@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/sched.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) /* --------------------------------------------------------------------- */ /* * Return a scatterlist for some page-aligned vmalloc()'ed memory * block (NULL on errors). Memory for the scatterlist is allocated * using kmalloc. The caller must free the memory. */ static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages) { struct scatterlist *sglist; struct page *pg; int i; sglist = vzalloc(nr_pages * sizeof(*sglist)); 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: vfree(sglist); return NULL; } /* * Return a scatterlist for a an array of userpages (NULL on errors). * Memory for the scatterlist is allocated using kmalloc. The caller * must free the memory. */ static struct scatterlist *videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset, size_t size) { struct scatterlist *sglist; int i; if (NULL == pages[0]) return NULL; sglist = vmalloc(nr_pages * sizeof(*sglist)); if (NULL == sglist) return NULL; sg_init_table(sglist, nr_pages); if (PageHighMem(pages[0])) /* DMA to highmem pages might not work */ goto highmem; sg_set_page(&sglist[0], pages[0], min_t(size_t, PAGE_SIZE - offset, size), offset); size -= min_t(size_t, PAGE_SIZE - offset, size); 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], min_t(size_t, PAGE_SIZE, size), 0); size -= min_t(size_t, PAGE_SIZE, size); } return sglist; nopage: dprintk(2, "sgl: oops - no page\n"); vfree(sglist); return NULL; highmem: dprintk(2, "sgl: oops - highmem page\n"); vfree(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; } EXPORT_SYMBOL_GPL(videobuf_to_dma); void videobuf_dma_init(struct videobuf_dmabuf *dma) { memset(dma, 0, sizeof(*dma)); dma->magic = MAGIC_DMABUF; } EXPORT_SYMBOL_GPL(videobuf_dma_init); 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->size = size; 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); 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; } EXPORT_SYMBOL_GPL(videobuf_dma_init_user); 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->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT); if (NULL == dma->vaddr) { 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->vaddr, nr_pages << PAGE_SHIFT); memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT); dma->nr_pages = nr_pages; return 0; } EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel); 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; } EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay); int videobuf_dma_map(struct device *dev, 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, dma->size); } if (dma->vaddr) { dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr, dma->nr_pages); } if (dma->bus_addr) { dma->sglist = vmalloc(sizeof(*dma->sglist)); 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(dev, dma->sglist, dma->nr_pages, dma->direction); if (0 == dma->sglen) { printk(KERN_WARNING "%s: videobuf_map_sg failed\n", __func__); vfree(dma->sglist); dma->sglist = NULL; dma->sglen = 0; return -ENOMEM; } } return 0; } EXPORT_SYMBOL_GPL(videobuf_dma_map); int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma) { MAGIC_CHECK(dma->magic, MAGIC_DMABUF); if (!dma->sglen) return 0; dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction); vfree(dma->sglist); dma->sglist = NULL; dma->sglen = 0; return 0; } EXPORT_SYMBOL_GPL(videobuf_dma_unmap); int videobuf_dma_free(struct videobuf_dmabuf *dma) { int i; MAGIC_CHECK(dma->magic, MAGIC_DMABUF); BUG_ON(dma->sglen); if (dma->pages) { for (i = 0; i < dma->nr_pages; i++) page_cache_release(dma->pages[i]); kfree(dma->pages); dma->pages = NULL; } vfree(dma->vaddr); dma->vaddr = NULL; if (dma->bus_addr) dma->bus_addr = 0; dma->direction = DMA_NONE; return 0; } EXPORT_SYMBOL_GPL(videobuf_dma_free); /* --------------------------------------------------------------------- */ 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); videobuf_queue_lock(q); 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]); } videobuf_queue_unlock(q); 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_highpage(page, (unsigned long)vmf->virtual_address); vmf->page = page; return 0; } static const 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 struct videobuf_buffer *__videobuf_alloc_vb(size_t size) { struct videobuf_dma_sg_memory *mem; struct videobuf_buffer *vb; vb = kzalloc(size + sizeof(*mem), GFP_KERNEL); if (!vb) return vb; 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 void *__videobuf_to_vaddr(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.vaddr; } 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->dev, &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 || !mem->dma.sglen); MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF); dma_sync_sg_for_cpu(q->dev, mem->dma.sglist, mem->dma.sglen, mem->dma.direction); return 0; } static int __videobuf_mmap_mapper(struct videobuf_queue *q, struct videobuf_buffer *buf, struct vm_area_struct *vma) { struct videobuf_dma_sg_memory *mem = buf->priv; struct videobuf_mapping *map; unsigned int first, last, size = 0, i; int retval; retval = -EINVAL; BUG_ON(!mem); MAGIC_CHECK(mem->magic, MAGIC_SG_MEM); /* look for first buffer to map */ for (first = 0; first < VIDEO_MAX_FRAME; first++) { if (buf == q->bufs[first]) { size = PAGE_ALIGN(q->bufs[first]->bsize); break; } } /* paranoia, should never happen since buf is always valid. */ if (!size) { dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n", (vma->vm_pgoff << PAGE_SHIFT)); goto done; } last = first; /* 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 += PAGE_ALIGN(q->bufs[i]->bsize); } map->count = 1; 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 struct videobuf_qtype_ops sg_ops = { .magic = MAGIC_QTYPE_OPS, .alloc_vb = __videobuf_alloc_vb, .iolock = __videobuf_iolock, .sync = __videobuf_sync, .mmap_mapper = __videobuf_mmap_mapper, .vaddr = __videobuf_to_vaddr, }; 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_vb(&q); } EXPORT_SYMBOL_GPL(videobuf_sg_alloc); 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) { videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize, priv, &sg_ops, ext_lock); } EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);