1/*
  2 * Copyright 2012 Red Hat Inc
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice (including the next
 12 * paragraph) shall be included in all copies or substantial portions of the
 13 * Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 21 * DEALINGS IN THE SOFTWARE.
 22 *
 23 * Authors:
 24 *	Dave Airlie <airlied@redhat.com>
 25 */
 26
 27#include <linux/dma-buf.h>
 28#include <linux/reservation.h>
 29
 30#include <drm/drmP.h>
 31
 32#include "i915_drv.h"
 33
 34static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf)
 35{
 36	return to_intel_bo(buf->priv);
 37}
 38
 39static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
 40					     enum dma_data_direction dir)
 41{
 42	struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
 43	struct sg_table *st;
 44	struct scatterlist *src, *dst;
 45	int ret, i;
 46
 47	ret = i915_gem_object_pin_pages(obj);
 48	if (ret)
 49		goto err;
 50
 51	/* Copy sg so that we make an independent mapping */
 52	st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 53	if (st == NULL) {
 54		ret = -ENOMEM;
 55		goto err_unpin_pages;
 56	}
 57
 58	ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL);
 59	if (ret)
 60		goto err_free;
 61
 62	src = obj->mm.pages->sgl;
 63	dst = st->sgl;
 64	for (i = 0; i < obj->mm.pages->nents; i++) {
 65		sg_set_page(dst, sg_page(src), src->length, 0);
 66		dst = sg_next(dst);
 67		src = sg_next(src);
 68	}
 69
 70	if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) {
 71		ret = -ENOMEM;
 72		goto err_free_sg;
 73	}
 74
 75	return st;
 76
 77err_free_sg:
 78	sg_free_table(st);
 79err_free:
 80	kfree(st);
 81err_unpin_pages:
 82	i915_gem_object_unpin_pages(obj);
 83err:
 84	return ERR_PTR(ret);
 85}
 86
 87static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 88				   struct sg_table *sg,
 89				   enum dma_data_direction dir)
 90{
 91	struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
 92
 93	dma_unmap_sg(attachment->dev, sg->sgl, sg->nents, dir);
 94	sg_free_table(sg);
 95	kfree(sg);
 96
 97	i915_gem_object_unpin_pages(obj);
 98}
 99
100static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
101{
102	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
103
104	return i915_gem_object_pin_map(obj, I915_MAP_WB);
105}
106
107static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
108{
109	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
110
111	i915_gem_object_unpin_map(obj);
112}
113
114static void *i915_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf, unsigned long page_num)
115{
116	return NULL;
117}
118
119static void i915_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
120{
121
122}
123static void *i915_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
124{
125	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
126	struct page *page;
127
128	if (page_num >= obj->base.size >> PAGE_SHIFT)
129		return NULL;
130
131	if (!i915_gem_object_has_struct_page(obj))
132		return NULL;
133
134	if (i915_gem_object_pin_pages(obj))
135		return NULL;
136
137	/* Synchronisation is left to the caller (via .begin_cpu_access()) */
138	page = i915_gem_object_get_page(obj, page_num);
139	if (IS_ERR(page))
140		goto err_unpin;
141
142	return kmap(page);
143
144err_unpin:
145	i915_gem_object_unpin_pages(obj);
146	return NULL;
147}
148
149static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
150{
151	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
152
153	kunmap(virt_to_page(addr));
154	i915_gem_object_unpin_pages(obj);
155}
156
157static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
158{
159	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
160	int ret;
161
162	if (obj->base.size < vma->vm_end - vma->vm_start)
163		return -EINVAL;
164
165	if (!obj->base.filp)
166		return -ENODEV;
167
168	ret = call_mmap(obj->base.filp, vma);
169	if (ret)
170		return ret;
171
172	fput(vma->vm_file);
173	vma->vm_file = get_file(obj->base.filp);
174
175	return 0;
176}
177
178static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
179{
180	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
181	struct drm_device *dev = obj->base.dev;
182	bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
183	int err;
184
185	err = i915_gem_object_pin_pages(obj);
186	if (err)
187		return err;
188
189	err = i915_mutex_lock_interruptible(dev);
190	if (err)
191		goto out;
192
193	err = i915_gem_object_set_to_cpu_domain(obj, write);
194	mutex_unlock(&dev->struct_mutex);
195
196out:
197	i915_gem_object_unpin_pages(obj);
198	return err;
199}
200
201static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
202{
203	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
204	struct drm_device *dev = obj->base.dev;
205	int err;
206
207	err = i915_gem_object_pin_pages(obj);
208	if (err)
209		return err;
210
211	err = i915_mutex_lock_interruptible(dev);
212	if (err)
213		goto out;
214
215	err = i915_gem_object_set_to_gtt_domain(obj, false);
216	mutex_unlock(&dev->struct_mutex);
217
218out:
219	i915_gem_object_unpin_pages(obj);
220	return err;
221}
222
223static const struct dma_buf_ops i915_dmabuf_ops =  {
224	.map_dma_buf = i915_gem_map_dma_buf,
225	.unmap_dma_buf = i915_gem_unmap_dma_buf,
226	.release = drm_gem_dmabuf_release,
227	.map = i915_gem_dmabuf_kmap,
228	.map_atomic = i915_gem_dmabuf_kmap_atomic,
229	.unmap = i915_gem_dmabuf_kunmap,
230	.unmap_atomic = i915_gem_dmabuf_kunmap_atomic,
231	.mmap = i915_gem_dmabuf_mmap,
232	.vmap = i915_gem_dmabuf_vmap,
233	.vunmap = i915_gem_dmabuf_vunmap,
234	.begin_cpu_access = i915_gem_begin_cpu_access,
235	.end_cpu_access = i915_gem_end_cpu_access,
236};
237
238struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
239				      struct drm_gem_object *gem_obj, int flags)
240{
241	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
242	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
243
244	exp_info.ops = &i915_dmabuf_ops;
245	exp_info.size = gem_obj->size;
246	exp_info.flags = flags;
247	exp_info.priv = gem_obj;
248	exp_info.resv = obj->resv;
249
250	if (obj->ops->dmabuf_export) {
251		int ret = obj->ops->dmabuf_export(obj);
252		if (ret)
253			return ERR_PTR(ret);
254	}
255
256	return drm_gem_dmabuf_export(dev, &exp_info);
257}
258
259static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
260{
261	struct sg_table *pages;
262	unsigned int sg_page_sizes;
263
264	pages = dma_buf_map_attachment(obj->base.import_attach,
265				       DMA_BIDIRECTIONAL);
266	if (IS_ERR(pages))
267		return PTR_ERR(pages);
268
269	sg_page_sizes = i915_sg_page_sizes(pages->sgl);
270
271	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
272
273	return 0;
274}
275
276static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,
277					     struct sg_table *pages)
278{
279	dma_buf_unmap_attachment(obj->base.import_attach, pages,
280				 DMA_BIDIRECTIONAL);
281}
282
283static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
284	.get_pages = i915_gem_object_get_pages_dmabuf,
285	.put_pages = i915_gem_object_put_pages_dmabuf,
286};
287
288struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
289					     struct dma_buf *dma_buf)
290{
291	struct dma_buf_attachment *attach;
292	struct drm_i915_gem_object *obj;
293	int ret;
294
295	/* is this one of own objects? */
296	if (dma_buf->ops == &i915_dmabuf_ops) {
297		obj = dma_buf_to_obj(dma_buf);
298		/* is it from our device? */
299		if (obj->base.dev == dev) {
300			/*
301			 * Importing dmabuf exported from out own gem increases
302			 * refcount on gem itself instead of f_count of dmabuf.
303			 */
304			return &i915_gem_object_get(obj)->base;
305		}
306	}
307
308	/* need to attach */
309	attach = dma_buf_attach(dma_buf, dev->dev);
310	if (IS_ERR(attach))
311		return ERR_CAST(attach);
312
313	get_dma_buf(dma_buf);
314
315	obj = i915_gem_object_alloc(to_i915(dev));
316	if (obj == NULL) {
317		ret = -ENOMEM;
318		goto fail_detach;
319	}
320
321	drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
322	i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops);
323	obj->base.import_attach = attach;
324	obj->resv = dma_buf->resv;
325
326	/* We use GTT as shorthand for a coherent domain, one that is
327	 * neither in the GPU cache nor in the CPU cache, where all
328	 * writes are immediately visible in memory. (That's not strictly
329	 * true, but it's close! There are internal buffers such as the
330	 * write-combined buffer or a delay through the chipset for GTT
331	 * writes that do require us to treat GTT as a separate cache domain.)
332	 */
333	obj->read_domains = I915_GEM_DOMAIN_GTT;
334	obj->write_domain = 0;
335
336	return &obj->base;
337
338fail_detach:
339	dma_buf_detach(dma_buf, attach);
340	dma_buf_put(dma_buf);
341
342	return ERR_PTR(ret);
343}
344
345#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
346#include "selftests/mock_dmabuf.c"
347#include "selftests/i915_gem_dmabuf.c"
348#endif