drivers/media/video/videobuf-dma-sg.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * helper functions for PCI 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/pci.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.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 = 0;
 module_param(debug, int, 0644);

 MODULE_DESCRIPTION("helper module to manage video4linux pci 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;
 	for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
 		pg = vmalloc_to_page(virt);
 		if (NULL == pg)
 			goto err;
 		BUG_ON(PageHighMem(pg));
 		sglist[i].page   = pg;
 		sglist[i].length = PAGE_SIZE;
 	}
 	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;

 	if (NULL == pages[0])
 		goto nopage;
 	if (PageHighMem(pages[0]))
 		/* DMA to highmem pages might not work */
 		goto highmem;
 	sglist[0].page   = pages[0];
 	sglist[0].offset = offset;
 	sglist[0].length = PAGE_SIZE - offset;
 	for (i = 1; i < nr_pages; i++) {
 		if (NULL == pages[i])
 			goto nopage;
 		if (PageHighMem(pages[i]))
 			goto highmem;
 		sglist[i].page   = pages[i];
 		sglist[i].length = PAGE_SIZE;
 	}
 	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 videbuf_pci_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 PCI_DMA_FROMDEVICE: rw = READ;  break;
 	case PCI_DMA_TODEVICE:   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(&current->mm->mmap_sem);
 	ret = videobuf_dma_init_user_locked(dma, direction, data, size);
 	up_read(&current->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)
 {
 	void                   *dev=q->dev;

 	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 = pci_map_sg(dev,dma->sglist,
 					dma->nr_pages, dma->direction);
 		if (0 == dma->sglen) {
 			printk(KERN_WARNING
 			       "%s: videobuf_map_sg failed\n",__FUNCTION__);
 			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)
 {
 	void                   *dev=q->dev;

 	MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
 	BUG_ON(!dma->sglen);

 	pci_dma_sync_sg_for_cpu (dev,dma->sglist,dma->nr_pages,dma->direction);
 	return 0;
 }

 int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
 {
 	void                   *dev=q->dev;

 	MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
 	if (!dma->sglen)
 		return 0;

 	pci_unmap_sg (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 = PCI_DMA_NONE;
 	return 0;
 }

 /* --------------------------------------------------------------------- */

 int videobuf_pci_dma_map(struct pci_dev *pci,struct videobuf_dmabuf *dma)
 {
 	struct videobuf_queue q;

 	q.dev=pci;

 	return (videobuf_dma_map(&q,dma));
 }

 int videobuf_pci_dma_unmap(struct pci_dev *pci,struct videobuf_dmabuf *dma)
 {
 	struct videobuf_queue q;

 	q.dev=pci;

 	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 videbuf_pci_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->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->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 struct page*
 videobuf_vm_nopage(struct vm_area_struct *vma, unsigned long vaddr,
 		   int *type)
 {
 	struct page *page;

 	dprintk(3,"nopage: fault @ %08lx [vma %08lx-%08lx]\n",
 		vaddr,vma->vm_start,vma->vm_end);
 	if (vaddr > vma->vm_end)
 		return NOPAGE_SIGBUS;
 	page = alloc_page(GFP_USER | __GFP_DMA32);
 	if (!page)
 		return NOPAGE_OOM;
 	clear_user_page(page_address(page), vaddr, page);
 	if (type)
 		*type = VM_FAULT_MINOR;
 	return page;
 }

 static struct vm_operations_struct videobuf_vm_ops =
 {
 	.open     = videobuf_vm_open,
 	.close    = videobuf_vm_close,
 	.nopage   = videobuf_vm_nopage,
 };

 /* ---------------------------------------------------------------------
  * PCI handlers for the generic methods
  */

 /* Allocated area consists on 3 parts:
 	struct video_buffer
 	struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 	struct videobuf_pci_sg_memory
  */

 static void *__videobuf_alloc(size_t size)
 {
 	struct videbuf_pci_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",
 		__FUNCTION__,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 videbuf_pci_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,
 							PCI_DMA_FROMDEVICE,
 							pages );
 			if (0 != err)
 				return err;
 		} else if (vb->memory == V4L2_MEMORY_USERPTR) {
 			/* dma directly to userspace */
 			err = videobuf_dma_init_user( &mem->dma,
 						      PCI_DMA_FROMDEVICE,
 						      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,
 						      PCI_DMA_FROMDEVICE,
 						      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,PCI_DMA_FROMDEVICE,
 						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 videbuf_pci_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 videbuf_pci_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;
 	}

 	/* 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;
 	for (size = 0, i = first; i <= last; size += q->bufs[i++]->bsize) {
 		q->bufs[i]->map   = map;
 		q->bufs[i]->baddr = vma->vm_start + size;
 	}
 	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 videbuf_pci_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 videbuf_pci_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 pci_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_pci_alloc (size_t size)
 {
 	struct videobuf_queue q;

 	/* Required to make generic handler to call __videobuf_alloc */
 	q.int_ops=&pci_ops;

 	q.msize=size;

 	return videobuf_alloc (&q);
 }

 void videobuf_queue_pci_init(struct videobuf_queue* q,
 			 struct videobuf_queue_ops *ops,
 			 void *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, &pci_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_pci_dma_map);
 EXPORT_SYMBOL_GPL(videobuf_pci_dma_unmap);
 EXPORT_SYMBOL_GPL(videobuf_pci_alloc);

 EXPORT_SYMBOL_GPL(videobuf_queue_pci_init);

 /*
  * Local variables:
  * c-basic-offset: 8
  * End:
  */
	/*
	* helper functions for PCI 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/pci.h>
	#include <linux/vmalloc.h>
	#include <linux/pagemap.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 = 0;
	module_param(debug, int, 0644);

	MODULE_DESCRIPTION("helper module to manage video4linux pci 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;
	for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
	pg = vmalloc_to_page(virt);
	if (NULL == pg)
	goto err;
	BUG_ON(PageHighMem(pg));
	sglist[i].page = pg;
	sglist[i].length = PAGE_SIZE;
	}
	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;

	if (NULL == pages[0])
	goto nopage;
	if (PageHighMem(pages[0]))
	/* DMA to highmem pages might not work */
	goto highmem;
	sglist[0].page = pages[0];
	sglist[0].offset = offset;
	sglist[0].length = PAGE_SIZE - offset;
	for (i = 1; i < nr_pages; i++) {
	if (NULL == pages[i])
	goto nopage;
	if (PageHighMem(pages[i]))
	goto highmem;
	sglist[i].page = pages[i];
	sglist[i].length = PAGE_SIZE;
	}
	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 videbuf_pci_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 PCI_DMA_FROMDEVICE: rw = READ; break;
	case PCI_DMA_TODEVICE: 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(&current->mm->mmap_sem);
	ret = videobuf_dma_init_user_locked(dma, direction, data, size);
	up_read(&current->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)
	{
	void *dev=q->dev;

	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 = pci_map_sg(dev,dma->sglist,
	dma->nr_pages, dma->direction);
	if (0 == dma->sglen) {
	printk(KERN_WARNING
	"%s: videobuf_map_sg failed\n",__FUNCTION__);
	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)
	{
	void *dev=q->dev;

	MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
	BUG_ON(!dma->sglen);

	pci_dma_sync_sg_for_cpu (dev,dma->sglist,dma->nr_pages,dma->direction);
	return 0;
	}

	int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
	{
	void *dev=q->dev;

	MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
	if (!dma->sglen)
	return 0;

	pci_unmap_sg (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 = PCI_DMA_NONE;
	return 0;
	}

	/* --------------------------------------------------------------------- */

	int videobuf_pci_dma_map(struct pci_dev pci,struct videobuf_dmabuf dma)
	{
	struct videobuf_queue q;

	q.dev=pci;

	return (videobuf_dma_map(&q,dma));
	}

	int videobuf_pci_dma_unmap(struct pci_dev pci,struct videobuf_dmabuf dma)
	{
	struct videobuf_queue q;

	q.dev=pci;

	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 videbuf_pci_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->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->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 struct page*
	videobuf_vm_nopage(struct vm_area_struct *vma, unsigned long vaddr,
	int *type)
	{
	struct page *page;

	dprintk(3,"nopage: fault @ %08lx [vma %08lx-%08lx]\n",
	vaddr,vma->vm_start,vma->vm_end);
	if (vaddr > vma->vm_end)
	return NOPAGE_SIGBUS;
	page = alloc_page(GFP_USER \| __GFP_DMA32);
	if (!page)
	return NOPAGE_OOM;
	clear_user_page(page_address(page), vaddr, page);
	if (type)
	*type = VM_FAULT_MINOR;
	return page;
	}

	static struct vm_operations_struct videobuf_vm_ops =
	{
	.open = videobuf_vm_open,
	.close = videobuf_vm_close,
	.nopage = videobuf_vm_nopage,
	};

	/* ---------------------------------------------------------------------
	* PCI handlers for the generic methods
	*/

	/* Allocated area consists on 3 parts:
	struct video_buffer
	struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
	struct videobuf_pci_sg_memory
	*/

	static void *__videobuf_alloc(size_t size)
	{
	struct videbuf_pci_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",
	__FUNCTION__,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 videbuf_pci_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,
	PCI_DMA_FROMDEVICE,
	pages );
	if (0 != err)
	return err;
	} else if (vb->memory == V4L2_MEMORY_USERPTR) {
	/* dma directly to userspace */
	err = videobuf_dma_init_user( &mem->dma,
	PCI_DMA_FROMDEVICE,
	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,
	PCI_DMA_FROMDEVICE,
	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,PCI_DMA_FROMDEVICE,
	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 videbuf_pci_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 videbuf_pci_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;
	}

	/* 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;
	for (size = 0, i = first; i <= last; size += q->bufs[i++]->bsize) {
	q->bufs[i]->map = map;
	q->bufs[i]->baddr = vma->vm_start + size;
	}
	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 videbuf_pci_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 videbuf_pci_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 pci_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_pci_alloc (size_t size)
	{
	struct videobuf_queue q;

	/* Required to make generic handler to call __videobuf_alloc */
	q.int_ops=&pci_ops;

	q.msize=size;

	return videobuf_alloc (&q);
	}

	void videobuf_queue_pci_init(struct videobuf_queue* q,
	struct videobuf_queue_ops *ops,
	void *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, &pci_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_pci_dma_map);
	EXPORT_SYMBOL_GPL(videobuf_pci_dma_unmap);
	EXPORT_SYMBOL_GPL(videobuf_pci_alloc);

	EXPORT_SYMBOL_GPL(videobuf_queue_pci_init);

	/*
	* Local variables:
	* c-basic-offset: 8
	* End:
	*/