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#include "drmP.h"
 27#include "i915_drv.h"
 28#include <linux/dma-buf.h>
 29
 30static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
 31				      enum dma_data_direction dir)
 32{
 33	struct drm_i915_gem_object *obj = attachment->dmabuf->priv;
 34	struct drm_device *dev = obj->base.dev;
 35	int npages = obj->base.size / PAGE_SIZE;
 36	struct sg_table *sg = NULL;
 37	int ret;
 38	int nents;
 39
 40	ret = i915_mutex_lock_interruptible(dev);
 41	if (ret)
 42		return ERR_PTR(ret);
 43
 44	if (!obj->pages) {
 45		ret = i915_gem_object_get_pages_gtt(obj, __GFP_NORETRY | __GFP_NOWARN);
 46		if (ret)
 47			goto out;
 48	}
 49
 50	/* link the pages into an SG then map the sg */
 51	sg = drm_prime_pages_to_sg(obj->pages, npages);
 52	nents = dma_map_sg(attachment->dev, sg->sgl, sg->nents, dir);
 53out:
 54	mutex_unlock(&dev->struct_mutex);
 55	return sg;
 56}
 57
 58static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 59			    struct sg_table *sg, enum dma_data_direction dir)
 60{
 61	dma_unmap_sg(attachment->dev, sg->sgl, sg->nents, dir);
 62	sg_free_table(sg);
 63	kfree(sg);
 64}
 65
 66static void i915_gem_dmabuf_release(struct dma_buf *dma_buf)
 67{
 68	struct drm_i915_gem_object *obj = dma_buf->priv;
 69
 70	if (obj->base.export_dma_buf == dma_buf) {
 71		/* drop the reference on the export fd holds */
 72		obj->base.export_dma_buf = NULL;
 73		drm_gem_object_unreference_unlocked(&obj->base);
 74	}
 75}
 76
 77static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 78{
 79	struct drm_i915_gem_object *obj = dma_buf->priv;
 80	struct drm_device *dev = obj->base.dev;
 81	int ret;
 82
 83	ret = i915_mutex_lock_interruptible(dev);
 84	if (ret)
 85		return ERR_PTR(ret);
 86
 87	if (obj->dma_buf_vmapping) {
 88		obj->vmapping_count++;
 89		goto out_unlock;
 90	}
 91
 92	if (!obj->pages) {
 93		ret = i915_gem_object_get_pages_gtt(obj, __GFP_NORETRY | __GFP_NOWARN);
 94		if (ret) {
 95			mutex_unlock(&dev->struct_mutex);
 96			return ERR_PTR(ret);
 97		}
 98	}
 99
100	obj->dma_buf_vmapping = vmap(obj->pages, obj->base.size / PAGE_SIZE, 0, PAGE_KERNEL);
101	if (!obj->dma_buf_vmapping) {
102		DRM_ERROR("failed to vmap object\n");
103		goto out_unlock;
104	}
105
106	obj->vmapping_count = 1;
107out_unlock:
108	mutex_unlock(&dev->struct_mutex);
109	return obj->dma_buf_vmapping;
110}
111
112static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
113{
114	struct drm_i915_gem_object *obj = dma_buf->priv;
115	struct drm_device *dev = obj->base.dev;
116	int ret;
117
118	ret = i915_mutex_lock_interruptible(dev);
119	if (ret)
120		return;
121
122	--obj->vmapping_count;
123	if (obj->vmapping_count == 0) {
124		vunmap(obj->dma_buf_vmapping);
125		obj->dma_buf_vmapping = NULL;
126	}
127	mutex_unlock(&dev->struct_mutex);
128}
129
130static void *i915_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf, unsigned long page_num)
131{
132	return NULL;
133}
134
135static void i915_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
136{
137
138}
139static void *i915_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
140{
141	return NULL;
142}
143
144static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
145{
146
147}
148
149static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
150{
151	return -EINVAL;
152}
153
154static const struct dma_buf_ops i915_dmabuf_ops =  {
155	.map_dma_buf = i915_gem_map_dma_buf,
156	.unmap_dma_buf = i915_gem_unmap_dma_buf,
157	.release = i915_gem_dmabuf_release,
158	.kmap = i915_gem_dmabuf_kmap,
159	.kmap_atomic = i915_gem_dmabuf_kmap_atomic,
160	.kunmap = i915_gem_dmabuf_kunmap,
161	.kunmap_atomic = i915_gem_dmabuf_kunmap_atomic,
162	.mmap = i915_gem_dmabuf_mmap,
163	.vmap = i915_gem_dmabuf_vmap,
164	.vunmap = i915_gem_dmabuf_vunmap,
165};
166
167struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
168				struct drm_gem_object *gem_obj, int flags)
169{
170	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
171
172	return dma_buf_export(obj, &i915_dmabuf_ops,
173						  obj->base.size, 0600);
174}
175
176struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
177				struct dma_buf *dma_buf)
178{
179	struct dma_buf_attachment *attach;
180	struct sg_table *sg;
181	struct drm_i915_gem_object *obj;
182	int npages;
183	int size;
184	int ret;
185
186	/* is this one of own objects? */
187	if (dma_buf->ops == &i915_dmabuf_ops) {
188		obj = dma_buf->priv;
189		/* is it from our device? */
190		if (obj->base.dev == dev) {
191			drm_gem_object_reference(&obj->base);
192			return &obj->base;
193		}
194	}
195
196	/* need to attach */
197	attach = dma_buf_attach(dma_buf, dev->dev);
198	if (IS_ERR(attach))
199		return ERR_CAST(attach);
200
201	sg = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
202	if (IS_ERR(sg)) {
203		ret = PTR_ERR(sg);
204		goto fail_detach;
205	}
206
207	size = dma_buf->size;
208	npages = size / PAGE_SIZE;
209
210	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
211	if (obj == NULL) {
212		ret = -ENOMEM;
213		goto fail_unmap;
214	}
215
216	ret = drm_gem_private_object_init(dev, &obj->base, size);
217	if (ret) {
218		kfree(obj);
219		goto fail_unmap;
220	}
221
222	obj->sg_table = sg;
223	obj->base.import_attach = attach;
224
225	return &obj->base;
226
227fail_unmap:
228	dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
229fail_detach:
230	dma_buf_detach(dma_buf, attach);
231	return ERR_PTR(ret);
232}