1 files changed, 359 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
new file mode 100644
index 00000000000..adefc31bb85
--- /dev/null
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -0,0 +1,359 @@
+/*
+ * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
+ *
+ * Copyright (C) 2010 Samsung Electronics
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <media/videobuf2-core.h>
+#include <media/videobuf2-memops.h>
+#include <media/videobuf2-dma-sg.h>
+
+static int debug;
+module_param(debug, int, 0644);
+
+#define dprintk(level, fmt, arg...)					\
+	do {								\
+		if (debug >= level)					\
+			printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);	\
+	} while (0)
+
+struct vb2_dma_sg_buf {
+	void				*vaddr;
+	struct page			**pages;
+	int				write;
+	int				offset;
+	struct sg_table			sg_table;
+	size_t				size;
+	unsigned int			num_pages;
+	atomic_t			refcount;
+	struct vb2_vmarea_handler	handler;
+	struct vm_area_struct		*vma;
+};
+
+static void vb2_dma_sg_put(void *buf_priv);
+
+static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
+		gfp_t gfp_flags)
+{
+	unsigned int last_page = 0;
+	int size = buf->size;
+
+	while (size > 0) {
+		struct page *pages;
+		int order;
+		int i;
+
+		order = get_order(size);
+		/* Dont over allocate*/
+		if ((PAGE_SIZE << order) > size)
+			order--;
+
+		pages = NULL;
+		while (!pages) {
+			pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
+					__GFP_NOWARN | gfp_flags, order);
+			if (pages)
+				break;
+
+			if (order == 0) {
+				while (last_page--)
+					__free_page(buf->pages[last_page]);
+				return -ENOMEM;
+			}
+			order--;
+		}
+
+		split_page(pages, order);
+		for (i = 0; i < (1 << order); i++)
+			buf->pages[last_page++] = &pages[i];
+
+		size -= PAGE_SIZE << order;
+	}
+
+	return 0;
+}
+
+static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
+{
+	struct vb2_dma_sg_buf *buf;
+	int ret;
+	int num_pages;
+
+	buf = kzalloc(sizeof *buf, GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	buf->vaddr = NULL;
+	buf->write = 0;
+	buf->offset = 0;
+	buf->size = size;
+	/* size is already page aligned */
+	buf->num_pages = size >> PAGE_SHIFT;
+
+	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
+			     GFP_KERNEL);
+	if (!buf->pages)
+		goto fail_pages_array_alloc;
+
+	ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
+	if (ret)
+		goto fail_pages_alloc;
+
+	ret = sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
+			buf->num_pages, 0, size, gfp_flags);
+	if (ret)
+		goto fail_table_alloc;
+
+	buf->handler.refcount = &buf->refcount;
+	buf->handler.put = vb2_dma_sg_put;
+	buf->handler.arg = buf;
+
+	atomic_inc(&buf->refcount);
+
+	dprintk(1, "%s: Allocated buffer of %d pages\n",
+		__func__, buf->num_pages);
+	return buf;
+
+fail_table_alloc:
+	num_pages = buf->num_pages;
+	while (num_pages--)
+		__free_page(buf->pages[num_pages]);
+fail_pages_alloc:
+	kfree(buf->pages);
+fail_pages_array_alloc:
+	kfree(buf);
+	return NULL;
+}
+
+static void vb2_dma_sg_put(void *buf_priv)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+	int i = buf->num_pages;
+
+	if (atomic_dec_and_test(&buf->refcount)) {
+		dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
+			buf->num_pages);
+		if (buf->vaddr)
+			vm_unmap_ram(buf->vaddr, buf->num_pages);
+		sg_free_table(&buf->sg_table);
+		while (--i >= 0)
+			__free_page(buf->pages[i]);
+		kfree(buf->pages);
+		kfree(buf);
+	}
+}
+
+static inline int vma_is_io(struct vm_area_struct *vma)
+{
+	return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
+}
+
+static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
+				    unsigned long size, int write)
+{
+	struct vb2_dma_sg_buf *buf;
+	unsigned long first, last;
+	int num_pages_from_user;
+	struct vm_area_struct *vma;
+
+	buf = kzalloc(sizeof *buf, GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	buf->vaddr = NULL;
+	buf->write = write;
+	buf->offset = vaddr & ~PAGE_MASK;
+	buf->size = size;
+
+	first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
+	last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
+	buf->num_pages = last - first + 1;
+
+	buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
+			     GFP_KERNEL);
+	if (!buf->pages)
+		goto userptr_fail_alloc_pages;
+
+	vma = find_vma(current->mm, vaddr);
+	if (!vma) {
+		dprintk(1, "no vma for address %lu\n", vaddr);
+		goto userptr_fail_find_vma;
+	}
+
+	if (vma->vm_end < vaddr + size) {
+		dprintk(1, "vma at %lu is too small for %lu bytes\n",
+			vaddr, size);
+		goto userptr_fail_find_vma;
+	}
+
+	buf->vma = vb2_get_vma(vma);
+	if (!buf->vma) {
+		dprintk(1, "failed to copy vma\n");
+		goto userptr_fail_find_vma;
+	}
+
+	if (vma_is_io(buf->vma)) {
+		for (num_pages_from_user = 0;
+		     num_pages_from_user < buf->num_pages;
+		     ++num_pages_from_user, vaddr += PAGE_SIZE) {
+			unsigned long pfn;
+
+			if (follow_pfn(vma, vaddr, &pfn)) {
+				dprintk(1, "no page for address %lu\n", vaddr);
+				break;
+			}
+			buf->pages[num_pages_from_user] = pfn_to_page(pfn);
+		}
+	} else
+		num_pages_from_user = get_user_pages(current, current->mm,
+					     vaddr & PAGE_MASK,
+					     buf->num_pages,
+					     write,
+					     1, /* force */
+					     buf->pages,
+					     NULL);
+
+	if (num_pages_from_user != buf->num_pages)
+		goto userptr_fail_get_user_pages;
+
+	if (sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
+			buf->num_pages, buf->offset, size, 0))
+		goto userptr_fail_alloc_table_from_pages;
+
+	return buf;
+
+userptr_fail_alloc_table_from_pages:
+userptr_fail_get_user_pages:
+	dprintk(1, "get_user_pages requested/got: %d/%d]\n",
+		buf->num_pages, num_pages_from_user);
+	if (!vma_is_io(buf->vma))
+		while (--num_pages_from_user >= 0)
+			put_page(buf->pages[num_pages_from_user]);
+	vb2_put_vma(buf->vma);
+userptr_fail_find_vma:
+	kfree(buf->pages);
+userptr_fail_alloc_pages:
+	kfree(buf);
+	return NULL;
+}
+
+/*
+ * @put_userptr: inform the allocator that a USERPTR buffer will no longer
+ *		 be used
+ */
+static void vb2_dma_sg_put_userptr(void *buf_priv)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+	int i = buf->num_pages;
+
+	dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
+	       __func__, buf->num_pages);
+	if (buf->vaddr)
+		vm_unmap_ram(buf->vaddr, buf->num_pages);
+	sg_free_table(&buf->sg_table);
+	while (--i >= 0) {
+		if (buf->write)
+			set_page_dirty_lock(buf->pages[i]);
+		if (!vma_is_io(buf->vma))
+			put_page(buf->pages[i]);
+	}
+	kfree(buf->pages);
+	vb2_put_vma(buf->vma);
+	kfree(buf);
+}
+
+static void *vb2_dma_sg_vaddr(void *buf_priv)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+
+	BUG_ON(!buf);
+
+	if (!buf->vaddr)
+		buf->vaddr = vm_map_ram(buf->pages,
+					buf->num_pages,
+					-1,
+					PAGE_KERNEL);
+
+	/* add offset in case userptr is not page-aligned */
+	return buf->vaddr + buf->offset;
+}
+
+static unsigned int vb2_dma_sg_num_users(void *buf_priv)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+
+	return atomic_read(&buf->refcount);
+}
+
+static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+	unsigned long uaddr = vma->vm_start;
+	unsigned long usize = vma->vm_end - vma->vm_start;
+	int i = 0;
+
+	if (!buf) {
+		printk(KERN_ERR "No memory to map\n");
+		return -EINVAL;
+	}
+
+	do {
+		int ret;
+
+		ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
+		if (ret) {
+			printk(KERN_ERR "Remapping memory, error: %d\n", ret);
+			return ret;
+		}
+
+		uaddr += PAGE_SIZE;
+		usize -= PAGE_SIZE;
+	} while (usize > 0);
+
+
+	/*
+	 * Use common vm_area operations to track buffer refcount.
+	 */
+	vma->vm_private_data	= &buf->handler;
+	vma->vm_ops		= &vb2_common_vm_ops;
+
+	vma->vm_ops->open(vma);
+
+	return 0;
+}
+
+static void *vb2_dma_sg_cookie(void *buf_priv)
+{
+	struct vb2_dma_sg_buf *buf = buf_priv;
+
+	return &buf->sg_table;
+}
+
+const struct vb2_mem_ops vb2_dma_sg_memops = {
+	.alloc		= vb2_dma_sg_alloc,
+	.put		= vb2_dma_sg_put,
+	.get_userptr	= vb2_dma_sg_get_userptr,
+	.put_userptr	= vb2_dma_sg_put_userptr,
+	.vaddr		= vb2_dma_sg_vaddr,
+	.mmap		= vb2_dma_sg_mmap,
+	.num_users	= vb2_dma_sg_num_users,
+	.cookie		= vb2_dma_sg_cookie,
+};
+EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
+
+MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
+MODULE_AUTHOR("Andrzej Pietrasiewicz");
+MODULE_LICENSE("GPL");