1/*
  2 * drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
  3 *
  4 * Copyright (C) 2011 Texas Instruments
  5 * Author: Rob Clark <rob.clark@linaro.org>
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms of the GNU General Public License version 2 as published by
  9 * the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope that it will be useful, but WITHOUT
 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 14 * more details.
 15 *
 16 * You should have received a copy of the GNU General Public License along with
 17 * this program.  If not, see <http://www.gnu.org/licenses/>.
 18 */
 19
 20#include "omap_drv.h"
 21
 22#include <linux/dma-buf.h>
 23
 24static struct sg_table *omap_gem_map_dma_buf(
 25		struct dma_buf_attachment *attachment,
 26		enum dma_data_direction dir)
 27{
 28	struct drm_gem_object *obj = attachment->dmabuf->priv;
 29	struct sg_table *sg;
 30	dma_addr_t paddr;
 31	int ret;
 32
 33	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
 34	if (!sg)
 35		return ERR_PTR(-ENOMEM);
 36
 37	/* camera, etc, need physically contiguous.. but we need a
 38	 * better way to know this..
 39	 */
 40	ret = omap_gem_get_paddr(obj, &paddr, true);
 41	if (ret)
 42		goto out;
 43
 44	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
 45	if (ret)
 46		goto out;
 47
 48	sg_init_table(sg->sgl, 1);
 49	sg_dma_len(sg->sgl) = obj->size;
 50	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(paddr)), obj->size, 0);
 51	sg_dma_address(sg->sgl) = paddr;
 52
 53	/* this should be after _get_paddr() to ensure we have pages attached */
 54	omap_gem_dma_sync(obj, dir);
 55
 56	return sg;
 57out:
 58	kfree(sg);
 59	return ERR_PTR(ret);
 60}
 61
 62static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 63		struct sg_table *sg, enum dma_data_direction dir)
 64{
 65	struct drm_gem_object *obj = attachment->dmabuf->priv;
 66	omap_gem_put_paddr(obj);
 67	sg_free_table(sg);
 68	kfree(sg);
 69}
 70
 71static void omap_gem_dmabuf_release(struct dma_buf *buffer)
 72{
 73	struct drm_gem_object *obj = buffer->priv;
 74	/* release reference that was taken when dmabuf was exported
 75	 * in omap_gem_prime_set()..
 76	 */
 77	drm_gem_object_unreference_unlocked(obj);
 78}
 79
 80
 81static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
 82		size_t start, size_t len, enum dma_data_direction dir)
 83{
 84	struct drm_gem_object *obj = buffer->priv;
 85	struct page **pages;
 86	if (omap_gem_flags(obj) & OMAP_BO_TILED) {
 87		/* TODO we would need to pin at least part of the buffer to
 88		 * get de-tiled view.  For now just reject it.
 89		 */
 90		return -ENOMEM;
 91	}
 92	/* make sure we have the pages: */
 93	return omap_gem_get_pages(obj, &pages, true);
 94}
 95
 96static void omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
 97		size_t start, size_t len, enum dma_data_direction dir)
 98{
 99	struct drm_gem_object *obj = buffer->priv;
100	omap_gem_put_pages(obj);
101}
102
103
104static void *omap_gem_dmabuf_kmap_atomic(struct dma_buf *buffer,
105		unsigned long page_num)
106{
107	struct drm_gem_object *obj = buffer->priv;
108	struct page **pages;
109	omap_gem_get_pages(obj, &pages, false);
110	omap_gem_cpu_sync(obj, page_num);
111	return kmap_atomic(pages[page_num]);
112}
113
114static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer,
115		unsigned long page_num, void *addr)
116{
117	kunmap_atomic(addr);
118}
119
120static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
121		unsigned long page_num)
122{
123	struct drm_gem_object *obj = buffer->priv;
124	struct page **pages;
125	omap_gem_get_pages(obj, &pages, false);
126	omap_gem_cpu_sync(obj, page_num);
127	return kmap(pages[page_num]);
128}
129
130static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
131		unsigned long page_num, void *addr)
132{
133	struct drm_gem_object *obj = buffer->priv;
134	struct page **pages;
135	omap_gem_get_pages(obj, &pages, false);
136	kunmap(pages[page_num]);
137}
138
139static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
140		struct vm_area_struct *vma)
141{
142	struct drm_gem_object *obj = buffer->priv;
143	struct drm_device *dev = obj->dev;
144	int ret = 0;
145
146	if (WARN_ON(!obj->filp))
147		return -EINVAL;
148
149	mutex_lock(&dev->struct_mutex);
150	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
151	mutex_unlock(&dev->struct_mutex);
152	if (ret < 0)
153		return ret;
154
155	return omap_gem_mmap_obj(obj, vma);
156}
157
158static struct dma_buf_ops omap_dmabuf_ops = {
159		.map_dma_buf = omap_gem_map_dma_buf,
160		.unmap_dma_buf = omap_gem_unmap_dma_buf,
161		.release = omap_gem_dmabuf_release,
162		.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
163		.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
164		.kmap_atomic = omap_gem_dmabuf_kmap_atomic,
165		.kunmap_atomic = omap_gem_dmabuf_kunmap_atomic,
166		.kmap = omap_gem_dmabuf_kmap,
167		.kunmap = omap_gem_dmabuf_kunmap,
168		.mmap = omap_gem_dmabuf_mmap,
169};
170
171struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
172		struct drm_gem_object *obj, int flags)
173{
174	return dma_buf_export(obj, &omap_dmabuf_ops, obj->size, flags);
175}
176
177struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
178		struct dma_buf *buffer)
179{
180	struct drm_gem_object *obj;
181
182	/* is this one of own objects? */
183	if (buffer->ops == &omap_dmabuf_ops) {
184		obj = buffer->priv;
185		/* is it from our device? */
186		if (obj->dev == dev) {
187			/*
188			 * Importing dmabuf exported from out own gem increases
189			 * refcount on gem itself instead of f_count of dmabuf.
190			 */
191			drm_gem_object_reference(obj);
192			return obj;
193		}
194	}
195
196	/*
197	 * TODO add support for importing buffers from other devices..
198	 * for now we don't need this but would be nice to add eventually
199	 */
200	return ERR_PTR(-EINVAL);
201}