[deliverable/linux.git] / drivers / media / video / videobuf2-dma-sg.c

/*
 * 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>

struct vb2_dma_sg_buf {
	void				*vaddr;
	struct page			**pages;
	int				write;
	int				offset;
	struct vb2_dma_sg_desc		sg_desc;
	atomic_t			refcount;
	struct vb2_vmarea_handler	handler;
};

static void vb2_dma_sg_put(void *buf_priv);

static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
{
	struct vb2_dma_sg_buf *buf;
	int i;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->vaddr = NULL;
	buf->write = 0;
	buf->offset = 0;
	buf->sg_desc.size = size;
	buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;

	buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages *
				      sizeof(*buf->sg_desc.sglist));
	if (!buf->sg_desc.sglist)
		goto fail_sglist_alloc;
	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);

	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
			     GFP_KERNEL);
	if (!buf->pages)
		goto fail_pages_array_alloc;

	for (i = 0; i < buf->sg_desc.num_pages; ++i) {
		buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
		if (NULL == buf->pages[i])
			goto fail_pages_alloc;
		sg_set_page(&buf->sg_desc.sglist[i],
			    buf->pages[i], PAGE_SIZE, 0);
	}

	buf->handler.refcount = &buf->refcount;
	buf->handler.put = vb2_dma_sg_put;
	buf->handler.arg = buf;

	atomic_inc(&buf->refcount);

	printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
		__func__, buf->sg_desc.num_pages);
	return buf;

fail_pages_alloc:
	while (--i >= 0)
		__free_page(buf->pages[i]);
	kfree(buf->pages);

fail_pages_array_alloc:
	vfree(buf->sg_desc.sglist);

fail_sglist_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->sg_desc.num_pages;

	if (atomic_dec_and_test(&buf->refcount)) {
		printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__,
			buf->sg_desc.num_pages);
		if (buf->vaddr)
			vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
		vfree(buf->sg_desc.sglist);
		while (--i >= 0)
			__free_page(buf->pages[i]);
		kfree(buf->pages);
		kfree(buf);
	}
}

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, i;

	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->vaddr = NULL;
	buf->write = write;
	buf->offset = vaddr & ~PAGE_MASK;
	buf->sg_desc.size = size;

	first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
	last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
	buf->sg_desc.num_pages = last - first + 1;

	buf->sg_desc.sglist = vzalloc(
		buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
	if (!buf->sg_desc.sglist)
		goto userptr_fail_sglist_alloc;

	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);

	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
			     GFP_KERNEL);
	if (!buf->pages)
		goto userptr_fail_pages_array_alloc;

	down_read(&current->mm->mmap_sem);
	num_pages_from_user = get_user_pages(current, current->mm,
					     vaddr & PAGE_MASK,
					     buf->sg_desc.num_pages,
					     write,
					     1, /* force */
					     buf->pages,
					     NULL);
	up_read(&current->mm->mmap_sem);
	if (num_pages_from_user != buf->sg_desc.num_pages)
		goto userptr_fail_get_user_pages;

	sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
		    PAGE_SIZE - buf->offset, buf->offset);
	size -= PAGE_SIZE - buf->offset;
	for (i = 1; i < buf->sg_desc.num_pages; ++i) {
		sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
			    min_t(size_t, PAGE_SIZE, size), 0);
		size -= min_t(size_t, PAGE_SIZE, size);
	}
	return buf;

userptr_fail_get_user_pages:
	printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n",
	       num_pages_from_user, buf->sg_desc.num_pages);
	while (--num_pages_from_user >= 0)
		put_page(buf->pages[num_pages_from_user]);
	kfree(buf->pages);

userptr_fail_pages_array_alloc:
	vfree(buf->sg_desc.sglist);

userptr_fail_sglist_alloc:
	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->sg_desc.num_pages;

	printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
	       __func__, buf->sg_desc.num_pages);
	if (buf->vaddr)
		vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
	while (--i >= 0) {
		if (buf->write)
			set_page_dirty_lock(buf->pages[i]);
		put_page(buf->pages[i]);
	}
	vfree(buf->sg_desc.sglist);
	kfree(buf->pages);
	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->sg_desc.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_desc;
}

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");
Commit	Line	Data
5ba3f757 AP	1	/*
	2	* videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
	3	*
	4	* Copyright (C) 2010 Samsung Electronics
	5	*
	6	* Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/mm.h>
	15	#include <linux/scatterlist.h>
	16	#include <linux/sched.h>
	17	#include <linux/slab.h>
	18	#include <linux/vmalloc.h>
	19
	20	#include <media/videobuf2-core.h>
	21	#include <media/videobuf2-memops.h>
	22	#include <media/videobuf2-dma-sg.h>
	23
	24	struct vb2_dma_sg_buf {
	25	void *vaddr;
	26	struct page **pages;
	27	int write;
	28	int offset;
	29	struct vb2_dma_sg_desc sg_desc;
	30	atomic_t refcount;
	31	struct vb2_vmarea_handler handler;
	32	};
	33
	34	static void vb2_dma_sg_put(void *buf_priv);
	35
	36	static void vb2_dma_sg_alloc(void alloc_ctx, unsigned long size)
	37	{
	38	struct vb2_dma_sg_buf *buf;
	39	int i;
	40
	41	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	42	if (!buf)
	43	return NULL;
	44
	45	buf->vaddr = NULL;
	46	buf->write = 0;
	47	buf->offset = 0;
	48	buf->sg_desc.size = size;
	49	buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
	50
fabc6b85	51	buf->sg_desc.sglist = vzalloc(buf->sg_desc.num_pages *
5ba3f757 AP	52	sizeof(*buf->sg_desc.sglist));
	53	if (!buf->sg_desc.sglist)
	54	goto fail_sglist_alloc;
5ba3f757 AP	55	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
	56
	57	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
	58	GFP_KERNEL);
	59	if (!buf->pages)
	60	goto fail_pages_array_alloc;
	61
	62	for (i = 0; i < buf->sg_desc.num_pages; ++i) {
a52a82fc	63	buf->pages[i] = alloc_page(GFP_KERNEL \| __GFP_ZERO \| __GFP_NOWARN);
5ba3f757 AP	64	if (NULL == buf->pages[i])
	65	goto fail_pages_alloc;
	66	sg_set_page(&buf->sg_desc.sglist[i],
	67	buf->pages[i], PAGE_SIZE, 0);
	68	}
	69
	70	buf->handler.refcount = &buf->refcount;
	71	buf->handler.put = vb2_dma_sg_put;
	72	buf->handler.arg = buf;
	73
	74	atomic_inc(&buf->refcount);
	75
	76	printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
	77	__func__, buf->sg_desc.num_pages);
5ba3f757 AP	78	return buf;
	79
	80	fail_pages_alloc:
	81	while (--i >= 0)
	82	__free_page(buf->pages[i]);
a9bb36aa	83	kfree(buf->pages);
5ba3f757 AP	84
	85	fail_pages_array_alloc:
	86	vfree(buf->sg_desc.sglist);
	87
	88	fail_sglist_alloc:
	89	kfree(buf);
	90	return NULL;
	91	}
	92
	93	static void vb2_dma_sg_put(void *buf_priv)
	94	{
	95	struct vb2_dma_sg_buf *buf = buf_priv;
	96	int i = buf->sg_desc.num_pages;
	97
	98	if (atomic_dec_and_test(&buf->refcount)) {
	99	printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__,
	100	buf->sg_desc.num_pages);
	101	if (buf->vaddr)
	102	vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
	103	vfree(buf->sg_desc.sglist);
	104	while (--i >= 0)
	105	__free_page(buf->pages[i]);
	106	kfree(buf->pages);
	107	kfree(buf);
	108	}
	109	}
	110
	111	static void vb2_dma_sg_get_userptr(void alloc_ctx, unsigned long vaddr,
	112	unsigned long size, int write)
	113	{
	114	struct vb2_dma_sg_buf *buf;
	115	unsigned long first, last;
	116	int num_pages_from_user, i;
	117
	118	buf = kzalloc(sizeof *buf, GFP_KERNEL);
	119	if (!buf)
	120	return NULL;
	121
	122	buf->vaddr = NULL;
	123	buf->write = write;
	124	buf->offset = vaddr & ~PAGE_MASK;
	125	buf->sg_desc.size = size;
	126
	127	first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
	128	last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
	129	buf->sg_desc.num_pages = last - first + 1;
	130
fabc6b85	131	buf->sg_desc.sglist = vzalloc(
5ba3f757 AP	132	buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
	133	if (!buf->sg_desc.sglist)
	134	goto userptr_fail_sglist_alloc;
	135
5ba3f757 AP	136	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
	137
	138	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
	139	GFP_KERNEL);
	140	if (!buf->pages)
	141	goto userptr_fail_pages_array_alloc;
	142
	143	down_read(&current->mm->mmap_sem);
	144	num_pages_from_user = get_user_pages(current, current->mm,
	145	vaddr & PAGE_MASK,
	146	buf->sg_desc.num_pages,
	147	write,
	148	1, /* force */
	149	buf->pages,
	150	NULL);
	151	up_read(&current->mm->mmap_sem);
	152	if (num_pages_from_user != buf->sg_desc.num_pages)
	153	goto userptr_fail_get_user_pages;
	154
	155	sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
	156	PAGE_SIZE - buf->offset, buf->offset);
	157	size -= PAGE_SIZE - buf->offset;
	158	for (i = 1; i < buf->sg_desc.num_pages; ++i) {
	159	sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
	160	min_t(size_t, PAGE_SIZE, size), 0);
	161	size -= min_t(size_t, PAGE_SIZE, size);
	162	}
	163	return buf;
	164
	165	userptr_fail_get_user_pages:
	166	printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n",
	167	num_pages_from_user, buf->sg_desc.num_pages);
	168	while (--num_pages_from_user >= 0)
	169	put_page(buf->pages[num_pages_from_user]);
a9bb36aa	170	kfree(buf->pages);
5ba3f757 AP	171
	172	userptr_fail_pages_array_alloc:
	173	vfree(buf->sg_desc.sglist);
	174
	175	userptr_fail_sglist_alloc:
	176	kfree(buf);
	177	return NULL;
	178	}
	179
	180	/*
	181	* @put_userptr: inform the allocator that a USERPTR buffer will no longer
	182	* be used
	183	*/
	184	static void vb2_dma_sg_put_userptr(void *buf_priv)
	185	{
	186	struct vb2_dma_sg_buf *buf = buf_priv;
	187	int i = buf->sg_desc.num_pages;
	188
	189	printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
	190	__func__, buf->sg_desc.num_pages);
	191	if (buf->vaddr)
	192	vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
	193	while (--i >= 0) {
	194	if (buf->write)
	195	set_page_dirty_lock(buf->pages[i]);
	196	put_page(buf->pages[i]);
	197	}
	198	vfree(buf->sg_desc.sglist);
	199	kfree(buf->pages);
	200	kfree(buf);
	201	}
	202
	203	static void vb2_dma_sg_vaddr(void buf_priv)
	204	{
	205	struct vb2_dma_sg_buf *buf = buf_priv;
	206
	207	BUG_ON(!buf);
	208
	209	if (!buf->vaddr)
	210	buf->vaddr = vm_map_ram(buf->pages,
	211	buf->sg_desc.num_pages,
	212	-1,
	213	PAGE_KERNEL);
	214
	215	/* add offset in case userptr is not page-aligned */
	216	return buf->vaddr + buf->offset;
	217	}
	218
	219	static unsigned int vb2_dma_sg_num_users(void *buf_priv)
	220	{
	221	struct vb2_dma_sg_buf *buf = buf_priv;
	222
	223	return atomic_read(&buf->refcount);
	224	}
	225
	226	static int vb2_dma_sg_mmap(void buf_priv, struct vm_area_struct vma)
	227	{
	228	struct vb2_dma_sg_buf *buf = buf_priv;
	229	unsigned long uaddr = vma->vm_start;
	230	unsigned long usize = vma->vm_end - vma->vm_start;
	231	int i = 0;
	232
	233	if (!buf) {
	234	printk(KERN_ERR "No memory to map\n");
235	return -EINVAL;
236	}
237
238	do {
239	int ret;
240
241	ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
242	if (ret) {
243	printk(KERN_ERR "Remapping memory, error: %d\n", ret);
244	return ret;
245	}
246
247	uaddr += PAGE_SIZE;
248	usize -= PAGE_SIZE;
249	} while (usize > 0);
250
251
252	/*
253	* Use common vm_area operations to track buffer refcount.
254	*/
255	vma->vm_private_data = &buf->handler;
256	vma->vm_ops = &vb2_common_vm_ops;
257
258	vma->vm_ops->open(vma);
259
260	return 0;
261	}
262
263	static void vb2_dma_sg_cookie(void buf_priv)
264	{
265	struct vb2_dma_sg_buf *buf = buf_priv;
266
267	return &buf->sg_desc;
268	}
269
270	const struct vb2_mem_ops vb2_dma_sg_memops = {
271	.alloc = vb2_dma_sg_alloc,
272	.put = vb2_dma_sg_put,
273	.get_userptr = vb2_dma_sg_get_userptr,
274	.put_userptr = vb2_dma_sg_put_userptr,
275	.vaddr = vb2_dma_sg_vaddr,
276	.mmap = vb2_dma_sg_mmap,
277	.num_users = vb2_dma_sg_num_users,
278	.cookie = vb2_dma_sg_cookie,
279	};
280	EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
281
282	MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
283	MODULE_AUTHOR("Andrzej Pietrasiewicz");
284	MODULE_LICENSE("GPL");