1/*
2 * videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.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/io.h>
14#include <linux/module.h>
15#include <linux/mm.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-vmalloc.h>
22#include <media/videobuf2-memops.h>
23
24struct vb2_vmalloc_buf {
25	void				*vaddr;
26	struct page			**pages;
27	struct vm_area_struct		*vma;
28	enum dma_data_direction		dma_dir;
29	unsigned long			size;
30	unsigned int			n_pages;
31	atomic_t			refcount;
32	struct vb2_vmarea_handler	handler;
33	struct dma_buf			*dbuf;
34};
35
36static void vb2_vmalloc_put(void *buf_priv);
37
38static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size,
39			       enum dma_data_direction dma_dir, gfp_t gfp_flags)
40{
41	struct vb2_vmalloc_buf *buf;
42
43	buf = kzalloc(sizeof(*buf), GFP_KERNEL | gfp_flags);
44	if (!buf)
45		return NULL;
46
47	buf->size = size;
48	buf->vaddr = vmalloc_user(buf->size);
49	buf->dma_dir = dma_dir;
50	buf->handler.refcount = &buf->refcount;
51	buf->handler.put = vb2_vmalloc_put;
52	buf->handler.arg = buf;
53
54	if (!buf->vaddr) {
55		pr_debug("vmalloc of size %ld failed\n", buf->size);
56		kfree(buf);
57		return NULL;
58	}
59
60	atomic_inc(&buf->refcount);
61	return buf;
62}
63
64static void vb2_vmalloc_put(void *buf_priv)
65{
66	struct vb2_vmalloc_buf *buf = buf_priv;
67
68	if (atomic_dec_and_test(&buf->refcount)) {
69		vfree(buf->vaddr);
70		kfree(buf);
71	}
72}
73
74static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
75				     unsigned long size,
76				     enum dma_data_direction dma_dir)
77{
78	struct vb2_vmalloc_buf *buf;
79	unsigned long first, last;
80	int n_pages, offset;
81	struct vm_area_struct *vma;
82	dma_addr_t physp;
83
84	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
85	if (!buf)
86		return NULL;
87
88	buf->dma_dir = dma_dir;
89	offset = vaddr & ~PAGE_MASK;
90	buf->size = size;
91
92
93	vma = find_vma(current->mm, vaddr);
94	if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
95		if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
96			goto fail_pages_array_alloc;
97		buf->vma = vma;
98		buf->vaddr = (__force void *)ioremap_nocache(physp, size);
99		if (!buf->vaddr)
100			goto fail_pages_array_alloc;
101	} else {
102		first = vaddr >> PAGE_SHIFT;
103		last  = (vaddr + size - 1) >> PAGE_SHIFT;
104		buf->n_pages = last - first + 1;
105		buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
106				     GFP_KERNEL);
107		if (!buf->pages)
108			goto fail_pages_array_alloc;
109
110		/* current->mm->mmap_sem is taken by videobuf2 core */
111		n_pages = get_user_pages(current, current->mm,
112					 vaddr & PAGE_MASK, buf->n_pages,
113					 dma_dir == DMA_FROM_DEVICE,
114					 1, /* force */
115					 buf->pages, NULL);
116		if (n_pages != buf->n_pages)
117			goto fail_get_user_pages;
118
119		buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
120					PAGE_KERNEL);
121		if (!buf->vaddr)
122			goto fail_get_user_pages;
123	}
124
125	buf->vaddr += offset;
126	return buf;
127
128fail_get_user_pages:
129	pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
130		 buf->n_pages);
131	while (--n_pages >= 0)
132		put_page(buf->pages[n_pages]);
133	kfree(buf->pages);
134
135fail_pages_array_alloc:
136	kfree(buf);
137
138	return NULL;
139}
140
141static void vb2_vmalloc_put_userptr(void *buf_priv)
142{
143	struct vb2_vmalloc_buf *buf = buf_priv;
144	unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
145	unsigned int i;
146
147	if (buf->pages) {
148		if (vaddr)
149			vm_unmap_ram((void *)vaddr, buf->n_pages);
150		for (i = 0; i < buf->n_pages; ++i) {
151			if (buf->dma_dir == DMA_FROM_DEVICE)
152				set_page_dirty_lock(buf->pages[i]);
153			put_page(buf->pages[i]);
154		}
155		kfree(buf->pages);
156	} else {
157		vb2_put_vma(buf->vma);
158		iounmap((__force void __iomem *)buf->vaddr);
159	}
160	kfree(buf);
161}
162
163static void *vb2_vmalloc_vaddr(void *buf_priv)
164{
165	struct vb2_vmalloc_buf *buf = buf_priv;
166
167	if (!buf->vaddr) {
168		pr_err("Address of an unallocated plane requested "
169		       "or cannot map user pointer\n");
170		return NULL;
171	}
172
173	return buf->vaddr;
174}
175
176static unsigned int vb2_vmalloc_num_users(void *buf_priv)
177{
178	struct vb2_vmalloc_buf *buf = buf_priv;
179	return atomic_read(&buf->refcount);
180}
181
182static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
183{
184	struct vb2_vmalloc_buf *buf = buf_priv;
185	int ret;
186
187	if (!buf) {
188		pr_err("No memory to map\n");
189		return -EINVAL;
190	}
191
192	ret = remap_vmalloc_range(vma, buf->vaddr, 0);
193	if (ret) {
194		pr_err("Remapping vmalloc memory, error: %d\n", ret);
195		return ret;
196	}
197
198	/*
199	 * Make sure that vm_areas for 2 buffers won't be merged together
200	 */
201	vma->vm_flags		|= VM_DONTEXPAND;
202
203	/*
204	 * Use common vm_area operations to track buffer refcount.
205	 */
206	vma->vm_private_data	= &buf->handler;
207	vma->vm_ops		= &vb2_common_vm_ops;
208
209	vma->vm_ops->open(vma);
210
211	return 0;
212}
213
214#ifdef CONFIG_HAS_DMA
215/*********************************************/
216/*         DMABUF ops for exporters          */
217/*********************************************/
218
219struct vb2_vmalloc_attachment {
220	struct sg_table sgt;
221	enum dma_data_direction dma_dir;
222};
223
224static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
225	struct dma_buf_attachment *dbuf_attach)
226{
227	struct vb2_vmalloc_attachment *attach;
228	struct vb2_vmalloc_buf *buf = dbuf->priv;
229	int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;
230	struct sg_table *sgt;
231	struct scatterlist *sg;
232	void *vaddr = buf->vaddr;
233	int ret;
234	int i;
235
236	attach = kzalloc(sizeof(*attach), GFP_KERNEL);
237	if (!attach)
238		return -ENOMEM;
239
240	sgt = &attach->sgt;
241	ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);
242	if (ret) {
243		kfree(attach);
244		return ret;
245	}
246	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
247		struct page *page = vmalloc_to_page(vaddr);
248
249		if (!page) {
250			sg_free_table(sgt);
251			kfree(attach);
252			return -ENOMEM;
253		}
254		sg_set_page(sg, page, PAGE_SIZE, 0);
255		vaddr += PAGE_SIZE;
256	}
257
258	attach->dma_dir = DMA_NONE;
259	dbuf_attach->priv = attach;
260	return 0;
261}
262
263static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,
264	struct dma_buf_attachment *db_attach)
265{
266	struct vb2_vmalloc_attachment *attach = db_attach->priv;
267	struct sg_table *sgt;
268
269	if (!attach)
270		return;
271
272	sgt = &attach->sgt;
273
274	/* release the scatterlist cache */
275	if (attach->dma_dir != DMA_NONE)
276		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
277			attach->dma_dir);
278	sg_free_table(sgt);
279	kfree(attach);
280	db_attach->priv = NULL;
281}
282
283static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
284	struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
285{
286	struct vb2_vmalloc_attachment *attach = db_attach->priv;
287	/* stealing dmabuf mutex to serialize map/unmap operations */
288	struct mutex *lock = &db_attach->dmabuf->lock;
289	struct sg_table *sgt;
290	int ret;
291
292	mutex_lock(lock);
293
294	sgt = &attach->sgt;
295	/* return previously mapped sg table */
296	if (attach->dma_dir == dma_dir) {
297		mutex_unlock(lock);
298		return sgt;
299	}
300
301	/* release any previous cache */
302	if (attach->dma_dir != DMA_NONE) {
303		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
304			attach->dma_dir);
305		attach->dma_dir = DMA_NONE;
306	}
307
308	/* mapping to the client with new direction */
309	ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);
310	if (ret <= 0) {
311		pr_err("failed to map scatterlist\n");
312		mutex_unlock(lock);
313		return ERR_PTR(-EIO);
314	}
315
316	attach->dma_dir = dma_dir;
317
318	mutex_unlock(lock);
319
320	return sgt;
321}
322
323static void vb2_vmalloc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
324	struct sg_table *sgt, enum dma_data_direction dma_dir)
325{
326	/* nothing to be done here */
327}
328
329static void vb2_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)
330{
331	/* drop reference obtained in vb2_vmalloc_get_dmabuf */
332	vb2_vmalloc_put(dbuf->priv);
333}
334
335static void *vb2_vmalloc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
336{
337	struct vb2_vmalloc_buf *buf = dbuf->priv;
338
339	return buf->vaddr + pgnum * PAGE_SIZE;
340}
341
342static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)
343{
344	struct vb2_vmalloc_buf *buf = dbuf->priv;
345
346	return buf->vaddr;
347}
348
349static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
350	struct vm_area_struct *vma)
351{
352	return vb2_vmalloc_mmap(dbuf->priv, vma);
353}
354
355static struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
356	.attach = vb2_vmalloc_dmabuf_ops_attach,
357	.detach = vb2_vmalloc_dmabuf_ops_detach,
358	.map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
359	.unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
360	.kmap = vb2_vmalloc_dmabuf_ops_kmap,
361	.kmap_atomic = vb2_vmalloc_dmabuf_ops_kmap,
362	.vmap = vb2_vmalloc_dmabuf_ops_vmap,
363	.mmap = vb2_vmalloc_dmabuf_ops_mmap,
364	.release = vb2_vmalloc_dmabuf_ops_release,
365};
366
367static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)
368{
369	struct vb2_vmalloc_buf *buf = buf_priv;
370	struct dma_buf *dbuf;
371	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
372
373	exp_info.ops = &vb2_vmalloc_dmabuf_ops;
374	exp_info.size = buf->size;
375	exp_info.flags = flags;
376	exp_info.priv = buf;
377
378	if (WARN_ON(!buf->vaddr))
379		return NULL;
380
381	dbuf = dma_buf_export(&exp_info);
382	if (IS_ERR(dbuf))
383		return NULL;
384
385	/* dmabuf keeps reference to vb2 buffer */
386	atomic_inc(&buf->refcount);
387
388	return dbuf;
389}
390#endif /* CONFIG_HAS_DMA */
391
392
393/*********************************************/
394/*       callbacks for DMABUF buffers        */
395/*********************************************/
396
397static int vb2_vmalloc_map_dmabuf(void *mem_priv)
398{
399	struct vb2_vmalloc_buf *buf = mem_priv;
400
401	buf->vaddr = dma_buf_vmap(buf->dbuf);
402
403	return buf->vaddr ? 0 : -EFAULT;
404}
405
406static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
407{
408	struct vb2_vmalloc_buf *buf = mem_priv;
409
410	dma_buf_vunmap(buf->dbuf, buf->vaddr);
411	buf->vaddr = NULL;
412}
413
414static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
415{
416	struct vb2_vmalloc_buf *buf = mem_priv;
417
418	if (buf->vaddr)
419		dma_buf_vunmap(buf->dbuf, buf->vaddr);
420
421	kfree(buf);
422}
423
424static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
425	unsigned long size, enum dma_data_direction dma_dir)
426{
427	struct vb2_vmalloc_buf *buf;
428
429	if (dbuf->size < size)
430		return ERR_PTR(-EFAULT);
431
432	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
433	if (!buf)
434		return ERR_PTR(-ENOMEM);
435
436	buf->dbuf = dbuf;
437	buf->dma_dir = dma_dir;
438	buf->size = size;
439
440	return buf;
441}
442
443
444const struct vb2_mem_ops vb2_vmalloc_memops = {
445	.alloc		= vb2_vmalloc_alloc,
446	.put		= vb2_vmalloc_put,
447	.get_userptr	= vb2_vmalloc_get_userptr,
448	.put_userptr	= vb2_vmalloc_put_userptr,
449#ifdef CONFIG_HAS_DMA
450	.get_dmabuf	= vb2_vmalloc_get_dmabuf,
451#endif
452	.map_dmabuf	= vb2_vmalloc_map_dmabuf,
453	.unmap_dmabuf	= vb2_vmalloc_unmap_dmabuf,
454	.attach_dmabuf	= vb2_vmalloc_attach_dmabuf,
455	.detach_dmabuf	= vb2_vmalloc_detach_dmabuf,
456	.vaddr		= vb2_vmalloc_vaddr,
457	.mmap		= vb2_vmalloc_mmap,
458	.num_users	= vb2_vmalloc_num_users,
459};
460EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
461
462MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
463MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
464MODULE_LICENSE("GPL");
465