1 files changed, 633 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
new file mode 100644
index 0000000..828e7c1
--- /dev/null
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -0,0 +1,633 @@
+/*
+ * 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(&current->mm->mmap_sem);
+	ret = videobuf_dma_init_user_locked(dma, direction, data, size);
+	up_read(&current->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_DONTDUMP;
+	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);
+