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/refcount.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <linux/vmalloc.h>
20
21#include <media/videobuf2-v4l2.h>
22#include <media/videobuf2-vmalloc.h>
23#include <media/videobuf2-memops.h>
24
25struct vb2_vmalloc_buf {
26	void				*vaddr;
27	struct frame_vector		*vec;
28	enum dma_data_direction		dma_dir;
29	unsigned long			size;
30	refcount_t			refcount;
31	struct vb2_vmarea_handler	handler;
32	struct dma_buf			*dbuf;
33};
34
35static void vb2_vmalloc_put(void *buf_priv);
36
37static void *vb2_vmalloc_alloc(struct device *dev, unsigned long attrs,
38			       unsigned long size, enum dma_data_direction dma_dir,
39			       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 ERR_PTR(-ENOMEM);
46
47	buf->size = size;
48	buf->vaddr = vmalloc_user(buf->size);
49	if (!buf->vaddr) {
50		pr_debug("vmalloc of size %ld failed\n", buf->size);
51		kfree(buf);
52		return ERR_PTR(-ENOMEM);
53	}
54
55	buf->dma_dir = dma_dir;
56	buf->handler.refcount = &buf->refcount;
57	buf->handler.put = vb2_vmalloc_put;
58	buf->handler.arg = buf;
59
60	refcount_set(&buf->refcount, 1);
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 (refcount_dec_and_test(&buf->refcount)) {
69		vfree(buf->vaddr);
70		kfree(buf);
71	}
72}
73
74static void *vb2_vmalloc_get_userptr(struct device *dev, unsigned long vaddr,
75				     unsigned long size,
76				     enum dma_data_direction dma_dir)
77{
78	struct vb2_vmalloc_buf *buf;
79	struct frame_vector *vec;
80	int n_pages, offset, i;
81	int ret = -ENOMEM;
82
83	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
84	if (!buf)
85		return ERR_PTR(-ENOMEM);
86
87	buf->dma_dir = dma_dir;
88	offset = vaddr & ~PAGE_MASK;
89	buf->size = size;
90	vec = vb2_create_framevec(vaddr, size);
91	if (IS_ERR(vec)) {
92		ret = PTR_ERR(vec);
93		goto fail_pfnvec_create;
94	}
95	buf->vec = vec;
96	n_pages = frame_vector_count(vec);
97	if (frame_vector_to_pages(vec) < 0) {
98		unsigned long *nums = frame_vector_pfns(vec);
99
100		/*
101		 * We cannot get page pointers for these pfns. Check memory is
102		 * physically contiguous and use direct mapping.
103		 */
104		for (i = 1; i < n_pages; i++)
105			if (nums[i-1] + 1 != nums[i])
106				goto fail_map;
107		buf->vaddr = (__force void *)
108			ioremap(__pfn_to_phys(nums[0]), size + offset);
109	} else {
110		buf->vaddr = vm_map_ram(frame_vector_pages(vec), n_pages, -1);
111	}
112
113	if (!buf->vaddr)
114		goto fail_map;
115	buf->vaddr += offset;
116	return buf;
117
118fail_map:
119	vb2_destroy_framevec(vec);
120fail_pfnvec_create:
121	kfree(buf);
122
123	return ERR_PTR(ret);
124}
125
126static void vb2_vmalloc_put_userptr(void *buf_priv)
127{
128	struct vb2_vmalloc_buf *buf = buf_priv;
129	unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
130	unsigned int i;
131	struct page **pages;
132	unsigned int n_pages;
133
134	if (!buf->vec->is_pfns) {
135		n_pages = frame_vector_count(buf->vec);
136		pages = frame_vector_pages(buf->vec);
137		if (vaddr)
138			vm_unmap_ram((void *)vaddr, n_pages);
139		if (buf->dma_dir == DMA_FROM_DEVICE ||
140		    buf->dma_dir == DMA_BIDIRECTIONAL)
141			for (i = 0; i < n_pages; i++)
142				set_page_dirty_lock(pages[i]);
143	} else {
144		iounmap((__force void __iomem *)buf->vaddr);
145	}
146	vb2_destroy_framevec(buf->vec);
147	kfree(buf);
148}
149
150static void *vb2_vmalloc_vaddr(void *buf_priv)
151{
152	struct vb2_vmalloc_buf *buf = buf_priv;
153
154	if (!buf->vaddr) {
155		pr_err("Address of an unallocated plane requested or cannot map user pointer\n");
156		return NULL;
157	}
158
159	return buf->vaddr;
160}
161
162static unsigned int vb2_vmalloc_num_users(void *buf_priv)
163{
164	struct vb2_vmalloc_buf *buf = buf_priv;
165	return refcount_read(&buf->refcount);
166}
167
168static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
169{
170	struct vb2_vmalloc_buf *buf = buf_priv;
171	int ret;
172
173	if (!buf) {
174		pr_err("No memory to map\n");
175		return -EINVAL;
176	}
177
178	ret = remap_vmalloc_range(vma, buf->vaddr, 0);
179	if (ret) {
180		pr_err("Remapping vmalloc memory, error: %d\n", ret);
181		return ret;
182	}
183
184	/*
185	 * Make sure that vm_areas for 2 buffers won't be merged together
186	 */
187	vma->vm_flags		|= VM_DONTEXPAND;
188
189	/*
190	 * Use common vm_area operations to track buffer refcount.
191	 */
192	vma->vm_private_data	= &buf->handler;
193	vma->vm_ops		= &vb2_common_vm_ops;
194
195	vma->vm_ops->open(vma);
196
197	return 0;
198}
199
200#ifdef CONFIG_HAS_DMA
201/*********************************************/
202/*         DMABUF ops for exporters          */
203/*********************************************/
204
205struct vb2_vmalloc_attachment {
206	struct sg_table sgt;
207	enum dma_data_direction dma_dir;
208};
209
210static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf,
211	struct dma_buf_attachment *dbuf_attach)
212{
213	struct vb2_vmalloc_attachment *attach;
214	struct vb2_vmalloc_buf *buf = dbuf->priv;
215	int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;
216	struct sg_table *sgt;
217	struct scatterlist *sg;
218	void *vaddr = buf->vaddr;
219	int ret;
220	int i;
221
222	attach = kzalloc(sizeof(*attach), GFP_KERNEL);
223	if (!attach)
224		return -ENOMEM;
225
226	sgt = &attach->sgt;
227	ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);
228	if (ret) {
229		kfree(attach);
230		return ret;
231	}
232	for_each_sgtable_sg(sgt, sg, i) {
233		struct page *page = vmalloc_to_page(vaddr);
234
235		if (!page) {
236			sg_free_table(sgt);
237			kfree(attach);
238			return -ENOMEM;
239		}
240		sg_set_page(sg, page, PAGE_SIZE, 0);
241		vaddr += PAGE_SIZE;
242	}
243
244	attach->dma_dir = DMA_NONE;
245	dbuf_attach->priv = attach;
246	return 0;
247}
248
249static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,
250	struct dma_buf_attachment *db_attach)
251{
252	struct vb2_vmalloc_attachment *attach = db_attach->priv;
253	struct sg_table *sgt;
254
255	if (!attach)
256		return;
257
258	sgt = &attach->sgt;
259
260	/* release the scatterlist cache */
261	if (attach->dma_dir != DMA_NONE)
262		dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
263	sg_free_table(sgt);
264	kfree(attach);
265	db_attach->priv = NULL;
266}
267
268static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
269	struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
270{
271	struct vb2_vmalloc_attachment *attach = db_attach->priv;
272	/* stealing dmabuf mutex to serialize map/unmap operations */
273	struct mutex *lock = &db_attach->dmabuf->lock;
274	struct sg_table *sgt;
275
276	mutex_lock(lock);
277
278	sgt = &attach->sgt;
279	/* return previously mapped sg table */
280	if (attach->dma_dir == dma_dir) {
281		mutex_unlock(lock);
282		return sgt;
283	}
284
285	/* release any previous cache */
286	if (attach->dma_dir != DMA_NONE) {
287		dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
288		attach->dma_dir = DMA_NONE;
289	}
290
291	/* mapping to the client with new direction */
292	if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
293		pr_err("failed to map scatterlist\n");
294		mutex_unlock(lock);
295		return ERR_PTR(-EIO);
296	}
297
298	attach->dma_dir = dma_dir;
299
300	mutex_unlock(lock);
301
302	return sgt;
303}
304
305static void vb2_vmalloc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
306	struct sg_table *sgt, enum dma_data_direction dma_dir)
307{
308	/* nothing to be done here */
309}
310
311static void vb2_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)
312{
313	/* drop reference obtained in vb2_vmalloc_get_dmabuf */
314	vb2_vmalloc_put(dbuf->priv);
315}
316
317static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)
318{
319	struct vb2_vmalloc_buf *buf = dbuf->priv;
320
321	return buf->vaddr;
322}
323
324static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
325	struct vm_area_struct *vma)
326{
327	return vb2_vmalloc_mmap(dbuf->priv, vma);
328}
329
330static const struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
331	.attach = vb2_vmalloc_dmabuf_ops_attach,
332	.detach = vb2_vmalloc_dmabuf_ops_detach,
333	.map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
334	.unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
335	.vmap = vb2_vmalloc_dmabuf_ops_vmap,
336	.mmap = vb2_vmalloc_dmabuf_ops_mmap,
337	.release = vb2_vmalloc_dmabuf_ops_release,
338};
339
340static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)
341{
342	struct vb2_vmalloc_buf *buf = buf_priv;
343	struct dma_buf *dbuf;
344	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
345
346	exp_info.ops = &vb2_vmalloc_dmabuf_ops;
347	exp_info.size = buf->size;
348	exp_info.flags = flags;
349	exp_info.priv = buf;
350
351	if (WARN_ON(!buf->vaddr))
352		return NULL;
353
354	dbuf = dma_buf_export(&exp_info);
355	if (IS_ERR(dbuf))
356		return NULL;
357
358	/* dmabuf keeps reference to vb2 buffer */
359	refcount_inc(&buf->refcount);
360
361	return dbuf;
362}
363#endif /* CONFIG_HAS_DMA */
364
365
366/*********************************************/
367/*       callbacks for DMABUF buffers        */
368/*********************************************/
369
370static int vb2_vmalloc_map_dmabuf(void *mem_priv)
371{
372	struct vb2_vmalloc_buf *buf = mem_priv;
373
374	buf->vaddr = dma_buf_vmap(buf->dbuf);
375
376	return buf->vaddr ? 0 : -EFAULT;
377}
378
379static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
380{
381	struct vb2_vmalloc_buf *buf = mem_priv;
382
383	dma_buf_vunmap(buf->dbuf, buf->vaddr);
384	buf->vaddr = NULL;
385}
386
387static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
388{
389	struct vb2_vmalloc_buf *buf = mem_priv;
390
391	if (buf->vaddr)
392		dma_buf_vunmap(buf->dbuf, buf->vaddr);
393
394	kfree(buf);
395}
396
397static void *vb2_vmalloc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
398	unsigned long size, enum dma_data_direction dma_dir)
399{
400	struct vb2_vmalloc_buf *buf;
401
402	if (dbuf->size < size)
403		return ERR_PTR(-EFAULT);
404
405	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
406	if (!buf)
407		return ERR_PTR(-ENOMEM);
408
409	buf->dbuf = dbuf;
410	buf->dma_dir = dma_dir;
411	buf->size = size;
412
413	return buf;
414}
415
416
417const struct vb2_mem_ops vb2_vmalloc_memops = {
418	.alloc		= vb2_vmalloc_alloc,
419	.put		= vb2_vmalloc_put,
420	.get_userptr	= vb2_vmalloc_get_userptr,
421	.put_userptr	= vb2_vmalloc_put_userptr,
422#ifdef CONFIG_HAS_DMA
423	.get_dmabuf	= vb2_vmalloc_get_dmabuf,
424#endif
425	.map_dmabuf	= vb2_vmalloc_map_dmabuf,
426	.unmap_dmabuf	= vb2_vmalloc_unmap_dmabuf,
427	.attach_dmabuf	= vb2_vmalloc_attach_dmabuf,
428	.detach_dmabuf	= vb2_vmalloc_detach_dmabuf,
429	.vaddr		= vb2_vmalloc_vaddr,
430	.mmap		= vb2_vmalloc_mmap,
431	.num_users	= vb2_vmalloc_num_users,
432};
433EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
434
435MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
436MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
437MODULE_LICENSE("GPL");
438