1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
  4 * Author: Rob Clark <rob.clark@linaro.org>
  5 */
  6
  7#include <linux/dma-buf.h>
  8#include <linux/highmem.h>
  9
 10#include <drm/drm_prime.h>
 11
 12#include "omap_drv.h"
 13
 14/* -----------------------------------------------------------------------------
 15 * DMABUF Export
 16 */
 17
 18static struct sg_table *omap_gem_map_dma_buf(
 19		struct dma_buf_attachment *attachment,
 20		enum dma_data_direction dir)
 21{
 22	struct drm_gem_object *obj = attachment->dmabuf->priv;
 23	struct sg_table *sg;
 24	dma_addr_t dma_addr;
 25	int ret;
 26
 27	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
 28	if (!sg)
 29		return ERR_PTR(-ENOMEM);
 30
 31	/* camera, etc, need physically contiguous.. but we need a
 32	 * better way to know this..
 33	 */
 34	ret = omap_gem_pin(obj, &dma_addr);
 35	if (ret)
 36		goto out;
 37
 38	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
 39	if (ret)
 40		goto out;
 41
 42	sg_init_table(sg->sgl, 1);
 43	sg_dma_len(sg->sgl) = obj->size;
 44	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
 45	sg_dma_address(sg->sgl) = dma_addr;
 46
 47	/* this must be after omap_gem_pin() to ensure we have pages attached */
 48	omap_gem_dma_sync_buffer(obj, dir);
 49
 50	return sg;
 51out:
 52	kfree(sg);
 53	return ERR_PTR(ret);
 54}
 55
 56static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 57		struct sg_table *sg, enum dma_data_direction dir)
 58{
 59	struct drm_gem_object *obj = attachment->dmabuf->priv;
 60	omap_gem_unpin(obj);
 61	sg_free_table(sg);
 62	kfree(sg);
 63}
 64
 65static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
 66		enum dma_data_direction dir)
 67{
 68	struct drm_gem_object *obj = buffer->priv;
 69	struct page **pages;
 70	if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
 71		/* TODO we would need to pin at least part of the buffer to
 72		 * get de-tiled view.  For now just reject it.
 73		 */
 74		return -ENOMEM;
 75	}
 76	/* make sure we have the pages: */
 77	return omap_gem_get_pages(obj, &pages, true);
 78}
 79
 80static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
 81					  enum dma_data_direction dir)
 82{
 83	struct drm_gem_object *obj = buffer->priv;
 84	omap_gem_put_pages(obj);
 85	return 0;
 86}
 87
 88static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 89		struct vm_area_struct *vma)
 90{
 91	struct drm_gem_object *obj = buffer->priv;
 92	int ret = 0;
 93
 94	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
 95	if (ret < 0)
 96		return ret;
 97
 98	return omap_gem_mmap_obj(obj, vma);
 99}
100
101static const struct dma_buf_ops omap_dmabuf_ops = {
102	.map_dma_buf = omap_gem_map_dma_buf,
103	.unmap_dma_buf = omap_gem_unmap_dma_buf,
104	.release = drm_gem_dmabuf_release,
105	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
106	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
107	.mmap = omap_gem_dmabuf_mmap,
108};
109
110struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
111{
112	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
113
114	exp_info.ops = &omap_dmabuf_ops;
115	exp_info.size = obj->size;
116	exp_info.flags = flags;
117	exp_info.priv = obj;
118
119	return drm_gem_dmabuf_export(obj->dev, &exp_info);
120}
121
122/* -----------------------------------------------------------------------------
123 * DMABUF Import
124 */
125
126struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
127					     struct dma_buf *dma_buf)
128{
129	struct dma_buf_attachment *attach;
130	struct drm_gem_object *obj;
131	struct sg_table *sgt;
132	int ret;
133
134	if (dma_buf->ops == &omap_dmabuf_ops) {
135		obj = dma_buf->priv;
136		if (obj->dev == dev) {
137			/*
138			 * Importing dmabuf exported from out own gem increases
139			 * refcount on gem itself instead of f_count of dmabuf.
140			 */
141			drm_gem_object_get(obj);
142			return obj;
143		}
144	}
145
146	attach = dma_buf_attach(dma_buf, dev->dev);
147	if (IS_ERR(attach))
148		return ERR_CAST(attach);
149
150	get_dma_buf(dma_buf);
151
152	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
153	if (IS_ERR(sgt)) {
154		ret = PTR_ERR(sgt);
155		goto fail_detach;
156	}
157
158	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
159	if (IS_ERR(obj)) {
160		ret = PTR_ERR(obj);
161		goto fail_unmap;
162	}
163
164	obj->import_attach = attach;
165
166	return obj;
167
168fail_unmap:
169	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
170fail_detach:
171	dma_buf_detach(dma_buf, attach);
172	dma_buf_put(dma_buf);
173
174	return ERR_PTR(ret);
175}