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 
25 struct 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 
35 static void vb2_vmalloc_put(void *buf_priv);
36 
37 static 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 
64 static 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 
74 static 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_nocache(__pfn_to_phys(nums[0]), size + offset);
109 	} else {
110 		buf->vaddr = vm_map_ram(frame_vector_pages(vec), n_pages, -1,
111 					PAGE_KERNEL);
112 	}
113 
114 	if (!buf->vaddr)
115 		goto fail_map;
116 	buf->vaddr += offset;
117 	return buf;
118 
119 fail_map:
120 	vb2_destroy_framevec(vec);
121 fail_pfnvec_create:
122 	kfree(buf);
123 
124 	return ERR_PTR(ret);
125 }
126 
127 static void vb2_vmalloc_put_userptr(void *buf_priv)
128 {
129 	struct vb2_vmalloc_buf *buf = buf_priv;
130 	unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
131 	unsigned int i;
132 	struct page **pages;
133 	unsigned int n_pages;
134 
135 	if (!buf->vec->is_pfns) {
136 		n_pages = frame_vector_count(buf->vec);
137 		pages = frame_vector_pages(buf->vec);
138 		if (vaddr)
139 			vm_unmap_ram((void *)vaddr, n_pages);
140 		if (buf->dma_dir == DMA_FROM_DEVICE ||
141 		    buf->dma_dir == DMA_BIDIRECTIONAL)
142 			for (i = 0; i < n_pages; i++)
143 				set_page_dirty_lock(pages[i]);
144 	} else {
145 		iounmap((__force void __iomem *)buf->vaddr);
146 	}
147 	vb2_destroy_framevec(buf->vec);
148 	kfree(buf);
149 }
150 
151 static void *vb2_vmalloc_vaddr(void *buf_priv)
152 {
153 	struct vb2_vmalloc_buf *buf = buf_priv;
154 
155 	if (!buf->vaddr) {
156 		pr_err("Address of an unallocated plane requested or cannot map user pointer\n");
157 		return NULL;
158 	}
159 
160 	return buf->vaddr;
161 }
162 
163 static unsigned int vb2_vmalloc_num_users(void *buf_priv)
164 {
165 	struct vb2_vmalloc_buf *buf = buf_priv;
166 	return refcount_read(&buf->refcount);
167 }
168 
169 static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
170 {
171 	struct vb2_vmalloc_buf *buf = buf_priv;
172 	int ret;
173 
174 	if (!buf) {
175 		pr_err("No memory to map\n");
176 		return -EINVAL;
177 	}
178 
179 	ret = remap_vmalloc_range(vma, buf->vaddr, 0);
180 	if (ret) {
181 		pr_err("Remapping vmalloc memory, error: %d\n", ret);
182 		return ret;
183 	}
184 
185 	/*
186 	 * Make sure that vm_areas for 2 buffers won't be merged together
187 	 */
188 	vma->vm_flags		|= VM_DONTEXPAND;
189 
190 	/*
191 	 * Use common vm_area operations to track buffer refcount.
192 	 */
193 	vma->vm_private_data	= &buf->handler;
194 	vma->vm_ops		= &vb2_common_vm_ops;
195 
196 	vma->vm_ops->open(vma);
197 
198 	return 0;
199 }
200 
201 #ifdef CONFIG_HAS_DMA
202 /*********************************************/
203 /*         DMABUF ops for exporters          */
204 /*********************************************/
205 
206 struct vb2_vmalloc_attachment {
207 	struct sg_table sgt;
208 	enum dma_data_direction dma_dir;
209 };
210 
211 static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf,
212 	struct dma_buf_attachment *dbuf_attach)
213 {
214 	struct vb2_vmalloc_attachment *attach;
215 	struct vb2_vmalloc_buf *buf = dbuf->priv;
216 	int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;
217 	struct sg_table *sgt;
218 	struct scatterlist *sg;
219 	void *vaddr = buf->vaddr;
220 	int ret;
221 	int i;
222 
223 	attach = kzalloc(sizeof(*attach), GFP_KERNEL);
224 	if (!attach)
225 		return -ENOMEM;
226 
227 	sgt = &attach->sgt;
228 	ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);
229 	if (ret) {
230 		kfree(attach);
231 		return ret;
232 	}
233 	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
234 		struct page *page = vmalloc_to_page(vaddr);
235 
236 		if (!page) {
237 			sg_free_table(sgt);
238 			kfree(attach);
239 			return -ENOMEM;
240 		}
241 		sg_set_page(sg, page, PAGE_SIZE, 0);
242 		vaddr += PAGE_SIZE;
243 	}
244 
245 	attach->dma_dir = DMA_NONE;
246 	dbuf_attach->priv = attach;
247 	return 0;
248 }
249 
250 static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,
251 	struct dma_buf_attachment *db_attach)
252 {
253 	struct vb2_vmalloc_attachment *attach = db_attach->priv;
254 	struct sg_table *sgt;
255 
256 	if (!attach)
257 		return;
258 
259 	sgt = &attach->sgt;
260 
261 	/* release the scatterlist cache */
262 	if (attach->dma_dir != DMA_NONE)
263 		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
264 			attach->dma_dir);
265 	sg_free_table(sgt);
266 	kfree(attach);
267 	db_attach->priv = NULL;
268 }
269 
270 static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
271 	struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
272 {
273 	struct vb2_vmalloc_attachment *attach = db_attach->priv;
274 	/* stealing dmabuf mutex to serialize map/unmap operations */
275 	struct mutex *lock = &db_attach->dmabuf->lock;
276 	struct sg_table *sgt;
277 
278 	mutex_lock(lock);
279 
280 	sgt = &attach->sgt;
281 	/* return previously mapped sg table */
282 	if (attach->dma_dir == dma_dir) {
283 		mutex_unlock(lock);
284 		return sgt;
285 	}
286 
287 	/* release any previous cache */
288 	if (attach->dma_dir != DMA_NONE) {
289 		dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
290 			attach->dma_dir);
291 		attach->dma_dir = DMA_NONE;
292 	}
293 
294 	/* mapping to the client with new direction */
295 	sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
296 				dma_dir);
297 	if (!sgt->nents) {
298 		pr_err("failed to map scatterlist\n");
299 		mutex_unlock(lock);
300 		return ERR_PTR(-EIO);
301 	}
302 
303 	attach->dma_dir = dma_dir;
304 
305 	mutex_unlock(lock);
306 
307 	return sgt;
308 }
309 
310 static void vb2_vmalloc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
311 	struct sg_table *sgt, enum dma_data_direction dma_dir)
312 {
313 	/* nothing to be done here */
314 }
315 
316 static void vb2_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)
317 {
318 	/* drop reference obtained in vb2_vmalloc_get_dmabuf */
319 	vb2_vmalloc_put(dbuf->priv);
320 }
321 
322 static void *vb2_vmalloc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
323 {
324 	struct vb2_vmalloc_buf *buf = dbuf->priv;
325 
326 	return buf->vaddr + pgnum * PAGE_SIZE;
327 }
328 
329 static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)
330 {
331 	struct vb2_vmalloc_buf *buf = dbuf->priv;
332 
333 	return buf->vaddr;
334 }
335 
336 static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
337 	struct vm_area_struct *vma)
338 {
339 	return vb2_vmalloc_mmap(dbuf->priv, vma);
340 }
341 
342 static const struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
343 	.attach = vb2_vmalloc_dmabuf_ops_attach,
344 	.detach = vb2_vmalloc_dmabuf_ops_detach,
345 	.map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
346 	.unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
347 	.map = vb2_vmalloc_dmabuf_ops_kmap,
348 	.vmap = vb2_vmalloc_dmabuf_ops_vmap,
349 	.mmap = vb2_vmalloc_dmabuf_ops_mmap,
350 	.release = vb2_vmalloc_dmabuf_ops_release,
351 };
352 
353 static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)
354 {
355 	struct vb2_vmalloc_buf *buf = buf_priv;
356 	struct dma_buf *dbuf;
357 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
358 
359 	exp_info.ops = &vb2_vmalloc_dmabuf_ops;
360 	exp_info.size = buf->size;
361 	exp_info.flags = flags;
362 	exp_info.priv = buf;
363 
364 	if (WARN_ON(!buf->vaddr))
365 		return NULL;
366 
367 	dbuf = dma_buf_export(&exp_info);
368 	if (IS_ERR(dbuf))
369 		return NULL;
370 
371 	/* dmabuf keeps reference to vb2 buffer */
372 	refcount_inc(&buf->refcount);
373 
374 	return dbuf;
375 }
376 #endif /* CONFIG_HAS_DMA */
377 
378 
379 /*********************************************/
380 /*       callbacks for DMABUF buffers        */
381 /*********************************************/
382 
383 static int vb2_vmalloc_map_dmabuf(void *mem_priv)
384 {
385 	struct vb2_vmalloc_buf *buf = mem_priv;
386 
387 	buf->vaddr = dma_buf_vmap(buf->dbuf);
388 
389 	return buf->vaddr ? 0 : -EFAULT;
390 }
391 
392 static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
393 {
394 	struct vb2_vmalloc_buf *buf = mem_priv;
395 
396 	dma_buf_vunmap(buf->dbuf, buf->vaddr);
397 	buf->vaddr = NULL;
398 }
399 
400 static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
401 {
402 	struct vb2_vmalloc_buf *buf = mem_priv;
403 
404 	if (buf->vaddr)
405 		dma_buf_vunmap(buf->dbuf, buf->vaddr);
406 
407 	kfree(buf);
408 }
409 
410 static void *vb2_vmalloc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
411 	unsigned long size, enum dma_data_direction dma_dir)
412 {
413 	struct vb2_vmalloc_buf *buf;
414 
415 	if (dbuf->size < size)
416 		return ERR_PTR(-EFAULT);
417 
418 	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
419 	if (!buf)
420 		return ERR_PTR(-ENOMEM);
421 
422 	buf->dbuf = dbuf;
423 	buf->dma_dir = dma_dir;
424 	buf->size = size;
425 
426 	return buf;
427 }
428 
429 
430 const struct vb2_mem_ops vb2_vmalloc_memops = {
431 	.alloc		= vb2_vmalloc_alloc,
432 	.put		= vb2_vmalloc_put,
433 	.get_userptr	= vb2_vmalloc_get_userptr,
434 	.put_userptr	= vb2_vmalloc_put_userptr,
435 #ifdef CONFIG_HAS_DMA
436 	.get_dmabuf	= vb2_vmalloc_get_dmabuf,
437 #endif
438 	.map_dmabuf	= vb2_vmalloc_map_dmabuf,
439 	.unmap_dmabuf	= vb2_vmalloc_unmap_dmabuf,
440 	.attach_dmabuf	= vb2_vmalloc_attach_dmabuf,
441 	.detach_dmabuf	= vb2_vmalloc_detach_dmabuf,
442 	.vaddr		= vb2_vmalloc_vaddr,
443 	.mmap		= vb2_vmalloc_mmap,
444 	.num_users	= vb2_vmalloc_num_users,
445 };
446 EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
447 
448 MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
449 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
450 MODULE_LICENSE("GPL");
451