[mirror_ubuntu-artful-kernel.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 = vmalloc(buf->sg_desc.num_pages *
				      sizeof(*buf->sg_desc.sglist));
	if (!buf->sg_desc.sglist)
		goto fail_sglist_alloc;
	memset(buf->sg_desc.sglist, 0, buf->sg_desc.num_pages *
	       sizeof(*buf->sg_desc.sglist));
	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);
		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);

	if (!buf->vaddr)
		buf->vaddr = vm_map_ram(buf->pages,
					buf->sg_desc.num_pages,
					-1,
					PAGE_KERNEL);
	return buf;

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

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

	memset(buf->sg_desc.sglist, 0,
		buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
	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]);

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
	51	buf->sg_desc.sglist = vmalloc(buf->sg_desc.num_pages *
	52	sizeof(*buf->sg_desc.sglist));
	53	if (!buf->sg_desc.sglist)
	54	goto fail_sglist_alloc;
	55	memset(buf->sg_desc.sglist, 0, buf->sg_desc.num_pages *
	56	sizeof(*buf->sg_desc.sglist));
	57	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
	58
	59	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
	60	GFP_KERNEL);
	61	if (!buf->pages)
	62	goto fail_pages_array_alloc;
	63
	64	for (i = 0; i < buf->sg_desc.num_pages; ++i) {
65	buf->pages[i] = alloc_page(GFP_KERNEL);
66	if (NULL == buf->pages[i])
67	goto fail_pages_alloc;
68	sg_set_page(&buf->sg_desc.sglist[i],
69	buf->pages[i], PAGE_SIZE, 0);
70	}
71
72	buf->handler.refcount = &buf->refcount;
73	buf->handler.put = vb2_dma_sg_put;
74	buf->handler.arg = buf;
75
76	atomic_inc(&buf->refcount);
77
78	printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
79	__func__, buf->sg_desc.num_pages);
80
81	if (!buf->vaddr)
82	buf->vaddr = vm_map_ram(buf->pages,
83	buf->sg_desc.num_pages,
84	-1,
85	PAGE_KERNEL);
86	return buf;
87
88	fail_pages_alloc:
89	while (--i >= 0)
90	__free_page(buf->pages[i]);
91
92	fail_pages_array_alloc:
93	vfree(buf->sg_desc.sglist);
94
95	fail_sglist_alloc:
96	kfree(buf);
97	return NULL;
98	}
99
100	static void vb2_dma_sg_put(void *buf_priv)
101	{
102	struct vb2_dma_sg_buf *buf = buf_priv;
103	int i = buf->sg_desc.num_pages;
104
105	if (atomic_dec_and_test(&buf->refcount)) {
106	printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__,
107	buf->sg_desc.num_pages);
108	if (buf->vaddr)
109	vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
110	vfree(buf->sg_desc.sglist);
111	while (--i >= 0)
112	__free_page(buf->pages[i]);
113	kfree(buf->pages);
114	kfree(buf);
115	}
116	}
117
118	static void vb2_dma_sg_get_userptr(void alloc_ctx, unsigned long vaddr,
119	unsigned long size, int write)
120	{
121	struct vb2_dma_sg_buf *buf;
122	unsigned long first, last;
123	int num_pages_from_user, i;
124
125	buf = kzalloc(sizeof *buf, GFP_KERNEL);
126	if (!buf)
127	return NULL;
128
129	buf->vaddr = NULL;
130	buf->write = write;
131	buf->offset = vaddr & ~PAGE_MASK;
132	buf->sg_desc.size = size;
133
134	first = (vaddr & PAGE_MASK) >> PAGE_SHIFT;
135	last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
136	buf->sg_desc.num_pages = last - first + 1;
137
138	buf->sg_desc.sglist = vmalloc(
139	buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
140	if (!buf->sg_desc.sglist)
141	goto userptr_fail_sglist_alloc;
142
143	memset(buf->sg_desc.sglist, 0,
144	buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
145	sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
146
147	buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
148	GFP_KERNEL);
149	if (!buf->pages)
150	goto userptr_fail_pages_array_alloc;
151
152	down_read(&current->mm->mmap_sem);
153	num_pages_from_user = get_user_pages(current, current->mm,
154	vaddr & PAGE_MASK,
155	buf->sg_desc.num_pages,
156	write,
157	1, /* force */
158	buf->pages,
159	NULL);
160	up_read(&current->mm->mmap_sem);
161	if (num_pages_from_user != buf->sg_desc.num_pages)
162	goto userptr_fail_get_user_pages;
163
164	sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
165	PAGE_SIZE - buf->offset, buf->offset);
166	size -= PAGE_SIZE - buf->offset;
167	for (i = 1; i < buf->sg_desc.num_pages; ++i) {
168	sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
169	min_t(size_t, PAGE_SIZE, size), 0);
170	size -= min_t(size_t, PAGE_SIZE, size);
171	}
172	return buf;
173
174	userptr_fail_get_user_pages:
175	printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n",
176	num_pages_from_user, buf->sg_desc.num_pages);
177	while (--num_pages_from_user >= 0)
178	put_page(buf->pages[num_pages_from_user]);
179
180	userptr_fail_pages_array_alloc:
181	vfree(buf->sg_desc.sglist);
182
183	userptr_fail_sglist_alloc:
184	kfree(buf);
185	return NULL;
186	}
187
188	/*
189	* @put_userptr: inform the allocator that a USERPTR buffer will no longer
190	* be used
191	*/
192	static void vb2_dma_sg_put_userptr(void *buf_priv)
193	{
194	struct vb2_dma_sg_buf *buf = buf_priv;
195	int i = buf->sg_desc.num_pages;
196
197	printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
198	__func__, buf->sg_desc.num_pages);
199	if (buf->vaddr)
200	vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
201	while (--i >= 0) {
202	if (buf->write)
203	set_page_dirty_lock(buf->pages[i]);
204	put_page(buf->pages[i]);
205	}
206	vfree(buf->sg_desc.sglist);
207	kfree(buf->pages);
208	kfree(buf);
209	}
210
211	static void vb2_dma_sg_vaddr(void buf_priv)
212	{
213	struct vb2_dma_sg_buf *buf = buf_priv;
214
215	BUG_ON(!buf);
216
217	if (!buf->vaddr)
218	buf->vaddr = vm_map_ram(buf->pages,
219	buf->sg_desc.num_pages,
220	-1,
221	PAGE_KERNEL);
222
223	/* add offset in case userptr is not page-aligned */
224	return buf->vaddr + buf->offset;
225	}
226
227	static unsigned int vb2_dma_sg_num_users(void *buf_priv)
228	{
229	struct vb2_dma_sg_buf *buf = buf_priv;
230
231	return atomic_read(&buf->refcount);
232	}
233
234	static int vb2_dma_sg_mmap(void buf_priv, struct vm_area_struct vma)
235	{
236	struct vb2_dma_sg_buf *buf = buf_priv;
237	unsigned long uaddr = vma->vm_start;
238	unsigned long usize = vma->vm_end - vma->vm_start;
239	int i = 0;
240
241	if (!buf) {
242	printk(KERN_ERR "No memory to map\n");
243	return -EINVAL;
244	}
245
246	do {
247	int ret;
248
249	ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
250	if (ret) {
251	printk(KERN_ERR "Remapping memory, error: %d\n", ret);
252	return ret;
253	}
254
255	uaddr += PAGE_SIZE;
256	usize -= PAGE_SIZE;
257	} while (usize > 0);
258
259
260	/*
261	* Use common vm_area operations to track buffer refcount.
262	*/
263	vma->vm_private_data = &buf->handler;
264	vma->vm_ops = &vb2_common_vm_ops;
265
266	vma->vm_ops->open(vma);
267
268	return 0;
269	}
270
271	static void vb2_dma_sg_cookie(void buf_priv)
272	{
273	struct vb2_dma_sg_buf *buf = buf_priv;
274
275	return &buf->sg_desc;
276	}
277
278	const struct vb2_mem_ops vb2_dma_sg_memops = {
279	.alloc = vb2_dma_sg_alloc,
280	.put = vb2_dma_sg_put,
281	.get_userptr = vb2_dma_sg_get_userptr,
282	.put_userptr = vb2_dma_sg_put_userptr,
283	.vaddr = vb2_dma_sg_vaddr,
284	.mmap = vb2_dma_sg_mmap,
285	.num_users = vb2_dma_sg_num_users,
286	.cookie = vb2_dma_sg_cookie,
287	};
288	EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
289
290	MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
291	MODULE_AUTHOR("Andrzej Pietrasiewicz");
292	MODULE_LICENSE("GPL");