1 files changed, 408 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c
new file mode 100644
index 0000000..67f572c
--- /dev/null
+++ b/drivers/media/v4l2-core/videobuf-dma-contig.c
@@ -0,0 +1,408 @@
+/*
+ * helper functions for physically contiguous capture buffers
+ *
+ * The functions support hardware lacking scatter gather support
+ * (i.e. the buffers must be linear in physical memory)
+ *
+ * Copyright (c) 2008 Magnus Damm
+ *
+ * Based on videobuf-vmalloc.c,
+ * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
+ *
+ * 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/mm.h>
+#include <linux/pagemap.h>
+#include <linux/dma-mapping.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <media/videobuf-dma-contig.h>
+
+struct videobuf_dma_contig_memory {
+	u32 magic;
+	void *vaddr;
+	dma_addr_t dma_handle;
+	unsigned long size;
+};
+
+#define MAGIC_DC_MEM 0x0733ac61
+#define MAGIC_CHECK(is, should)						    \
+	if (unlikely((is) != (should)))	{				    \
+		pr_err("magic mismatch: %x expected %x\n", (is), (should)); \
+		BUG();							    \
+	}
+
+static int __videobuf_dc_alloc(struct device *dev,
+			       struct videobuf_dma_contig_memory *mem,
+			       unsigned long size, gfp_t flags)
+{
+	mem->size = size;
+	mem->vaddr = dma_alloc_coherent(dev, mem->size,
+					&mem->dma_handle, flags);
+
+	if (!mem->vaddr) {
+		dev_err(dev, "memory alloc size %ld failed\n", mem->size);
+		return -ENOMEM;
+	}
+
+	dev_dbg(dev, "dma mapped data is at %p (%ld)\n", mem->vaddr, mem->size);
+
+	return 0;
+}
+
+static void __videobuf_dc_free(struct device *dev,
+			       struct videobuf_dma_contig_memory *mem)
+{
+	dma_free_coherent(dev, mem->size, mem->vaddr, mem->dma_handle);
+
+	mem->vaddr = NULL;
+}
+
+static void videobuf_vm_open(struct vm_area_struct *vma)
+{
+	struct videobuf_mapping *map = vma->vm_private_data;
+
+	dev_dbg(map->q->dev, "vm_open %p [count=%u,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;
+	int i;
+
+	dev_dbg(q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",
+		map, map->count, vma->vm_start, vma->vm_end);
+
+	map->count--;
+	if (0 == map->count) {
+		struct videobuf_dma_contig_memory *mem;
+
+		dev_dbg(q->dev, "munmap %p q=%p\n", map, q);
+		videobuf_queue_lock(q);
+
+		/* We need first to cancel streams, before unmapping */
+		if (q->streaming)
+			videobuf_queue_cancel(q);
+
+		for (i = 0; i < VIDEO_MAX_FRAME; i++) {
+			if (NULL == q->bufs[i])
+				continue;
+
+			if (q->bufs[i]->map != map)
+				continue;
+
+			mem = q->bufs[i]->priv;
+			if (mem) {
+				/* This callback is called only if kernel has
+				   allocated memory and this memory is mmapped.
+				   In this case, memory should be freed,
+				   in order to do memory unmap.
+				 */
+
+				MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+				/* vfree is not atomic - can't be
+				   called with IRQ's disabled
+				 */
+				dev_dbg(q->dev, "buf[%d] freeing %p\n",
+					i, mem->vaddr);
+
+				__videobuf_dc_free(q->dev, mem);
+				mem->vaddr = NULL;
+			}
+
+			q->bufs[i]->map = NULL;
+			q->bufs[i]->baddr = 0;
+		}
+
+		kfree(map);
+
+		videobuf_queue_unlock(q);
+	}
+}
+
+static const struct vm_operations_struct videobuf_vm_ops = {
+	.open	= videobuf_vm_open,
+	.close	= videobuf_vm_close,
+};
+
+/**
+ * videobuf_dma_contig_user_put() - reset pointer to user space buffer
+ * @mem: per-buffer private videobuf-dma-contig data
+ *
+ * This function resets the user space pointer
+ */
+static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
+{
+	mem->dma_handle = 0;
+	mem->size = 0;
+}
+
+/**
+ * videobuf_dma_contig_user_get() - setup user space memory pointer
+ * @mem: per-buffer private videobuf-dma-contig data
+ * @vb: video buffer to map
+ *
+ * This function validates and sets up a pointer to user space memory.
+ * Only physically contiguous pfn-mapped memory is accepted.
+ *
+ * Returns 0 if successful.
+ */
+static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
+					struct videobuf_buffer *vb)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	unsigned long prev_pfn, this_pfn;
+	unsigned long pages_done, user_address;
+	unsigned int offset;
+	int ret;
+
+	offset = vb->baddr & ~PAGE_MASK;
+	mem->size = PAGE_ALIGN(vb->size + offset);
+	ret = -EINVAL;
+
+	down_read(&mm->mmap_sem);
+
+	vma = find_vma(mm, vb->baddr);
+	if (!vma)
+		goto out_up;
+
+	if ((vb->baddr + mem->size) > vma->vm_end)
+		goto out_up;
+
+	pages_done = 0;
+	prev_pfn = 0; /* kill warning */
+	user_address = vb->baddr;
+
+	while (pages_done < (mem->size >> PAGE_SHIFT)) {
+		ret = follow_pfn(vma, user_address, &this_pfn);
+		if (ret)
+			break;
+
+		if (pages_done == 0)
+			mem->dma_handle = (this_pfn << PAGE_SHIFT) + offset;
+		else if (this_pfn != (prev_pfn + 1))
+			ret = -EFAULT;
+
+		if (ret)
+			break;
+
+		prev_pfn = this_pfn;
+		user_address += PAGE_SIZE;
+		pages_done++;
+	}
+
+out_up:
+	up_read(&current->mm->mmap_sem);
+
+	return ret;
+}
+
+static struct videobuf_buffer *__videobuf_alloc(size_t size)
+{
+	struct videobuf_dma_contig_memory *mem;
+	struct videobuf_buffer *vb;
+
+	vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
+	if (vb) {
+		vb->priv = ((char *)vb) + size;
+		mem = vb->priv;
+		mem->magic = MAGIC_DC_MEM;
+	}
+
+	return vb;
+}
+
+static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
+{
+	struct videobuf_dma_contig_memory *mem = buf->priv;
+
+	BUG_ON(!mem);
+	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+	return mem->vaddr;
+}
+
+static int __videobuf_iolock(struct videobuf_queue *q,
+			     struct videobuf_buffer *vb,
+			     struct v4l2_framebuffer *fbuf)
+{
+	struct videobuf_dma_contig_memory *mem = vb->priv;
+
+	BUG_ON(!mem);
+	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+	switch (vb->memory) {
+	case V4L2_MEMORY_MMAP:
+		dev_dbg(q->dev, "%s memory method MMAP\n", __func__);
+
+		/* All handling should be done by __videobuf_mmap_mapper() */
+		if (!mem->vaddr) {
+			dev_err(q->dev, "memory is not alloced/mmapped.\n");
+			return -EINVAL;
+		}
+		break;
+	case V4L2_MEMORY_USERPTR:
+		dev_dbg(q->dev, "%s memory method USERPTR\n", __func__);
+
+		/* handle pointer from user space */
+		if (vb->baddr)
+			return videobuf_dma_contig_user_get(mem, vb);
+
+		/* allocate memory for the read() method */
+		if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
+					GFP_KERNEL))
+			return -ENOMEM;
+		break;
+	case V4L2_MEMORY_OVERLAY:
+	default:
+		dev_dbg(q->dev, "%s memory method OVERLAY/unknown\n", __func__);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __videobuf_mmap_mapper(struct videobuf_queue *q,
+				  struct videobuf_buffer *buf,
+				  struct vm_area_struct *vma)
+{
+	struct videobuf_dma_contig_memory *mem;
+	struct videobuf_mapping *map;
+	int retval;
+	unsigned long size;
+
+	dev_dbg(q->dev, "%s\n", __func__);
+
+	/* create mapping + update buffer list */
+	map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+
+	buf->map = map;
+	map->q = q;
+
+	buf->baddr = vma->vm_start;
+
+	mem = buf->priv;
+	BUG_ON(!mem);
+	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+	if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
+				GFP_KERNEL | __GFP_COMP))
+		goto error;
+
+	/* Try to remap memory */
+
+	size = vma->vm_end - vma->vm_start;
+	size = (size < mem->size) ? size : mem->size;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	retval = remap_pfn_range(vma, vma->vm_start,
+				 mem->dma_handle >> PAGE_SHIFT,
+				 size, vma->vm_page_prot);
+	if (retval) {
+		dev_err(q->dev, "mmap: remap failed with error %d. ",
+			retval);
+		dma_free_coherent(q->dev, mem->size,
+				  mem->vaddr, mem->dma_handle);
+		goto error;
+	}
+
+	vma->vm_ops = &videobuf_vm_ops;
+	vma->vm_flags |= VM_DONTEXPAND;
+	vma->vm_private_data = map;
+
+	dev_dbg(q->dev, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
+		map, q, vma->vm_start, vma->vm_end,
+		(long int)buf->bsize, vma->vm_pgoff, buf->i);
+
+	videobuf_vm_open(vma);
+
+	return 0;
+
+error:
+	kfree(map);
+	return -ENOMEM;
+}
+
+static struct videobuf_qtype_ops qops = {
+	.magic		= MAGIC_QTYPE_OPS,
+	.alloc_vb	= __videobuf_alloc,
+	.iolock		= __videobuf_iolock,
+	.mmap_mapper	= __videobuf_mmap_mapper,
+	.vaddr		= __videobuf_to_vaddr,
+};
+
+void videobuf_queue_dma_contig_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, &qops, ext_lock);
+}
+EXPORT_SYMBOL_GPL(videobuf_queue_dma_contig_init);
+
+dma_addr_t videobuf_to_dma_contig(struct videobuf_buffer *buf)
+{
+	struct videobuf_dma_contig_memory *mem = buf->priv;
+
+	BUG_ON(!mem);
+	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+	return mem->dma_handle;
+}
+EXPORT_SYMBOL_GPL(videobuf_to_dma_contig);
+
+void videobuf_dma_contig_free(struct videobuf_queue *q,
+			      struct videobuf_buffer *buf)
+{
+	struct videobuf_dma_contig_memory *mem = buf->priv;
+
+	/* mmapped memory can't be freed here, otherwise mmapped region
+	   would be released, while still needed. In this case, the memory
+	   release should happen inside videobuf_vm_close().
+	   So, it should free memory only if the memory were allocated for
+	   read() operation.
+	 */
+	if (buf->memory != V4L2_MEMORY_USERPTR)
+		return;
+
+	if (!mem)
+		return;
+
+	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
+
+	/* handle user space pointer case */
+	if (buf->baddr) {
+		videobuf_dma_contig_user_put(mem);
+		return;
+	}
+
+	/* read() method */
+	if (mem->vaddr) {
+		__videobuf_dc_free(q->dev, mem);
+		mem->vaddr = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(videobuf_dma_contig_free);
+
+MODULE_DESCRIPTION("helper module to manage video4linux dma contig buffers");
+MODULE_AUTHOR("Magnus Damm");
+MODULE_LICENSE("GPL");