1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
4  * Author: Rob Clark <rob.clark@linaro.org>
5  */
6 
7 #include <linux/dma-buf.h>
8 
9 #include "omap_drv.h"
10 
11 /* -----------------------------------------------------------------------------
12  * DMABUF Export
13  */
14 
15 static struct sg_table *omap_gem_map_dma_buf(
16 		struct dma_buf_attachment *attachment,
17 		enum dma_data_direction dir)
18 {
19 	struct drm_gem_object *obj = attachment->dmabuf->priv;
20 	struct sg_table *sg;
21 	dma_addr_t dma_addr;
22 	int ret;
23 
24 	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
25 	if (!sg)
26 		return ERR_PTR(-ENOMEM);
27 
28 	/* camera, etc, need physically contiguous.. but we need a
29 	 * better way to know this..
30 	 */
31 	ret = omap_gem_pin(obj, &dma_addr);
32 	if (ret)
33 		goto out;
34 
35 	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
36 	if (ret)
37 		goto out;
38 
39 	sg_init_table(sg->sgl, 1);
40 	sg_dma_len(sg->sgl) = obj->size;
41 	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
42 	sg_dma_address(sg->sgl) = dma_addr;
43 
44 	/* this must be after omap_gem_pin() to ensure we have pages attached */
45 	omap_gem_dma_sync_buffer(obj, dir);
46 
47 	return sg;
48 out:
49 	kfree(sg);
50 	return ERR_PTR(ret);
51 }
52 
53 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
54 		struct sg_table *sg, enum dma_data_direction dir)
55 {
56 	struct drm_gem_object *obj = attachment->dmabuf->priv;
57 	omap_gem_unpin(obj);
58 	sg_free_table(sg);
59 	kfree(sg);
60 }
61 
62 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
63 		enum dma_data_direction dir)
64 {
65 	struct drm_gem_object *obj = buffer->priv;
66 	struct page **pages;
67 	if (omap_gem_flags(obj) & OMAP_BO_TILED) {
68 		/* TODO we would need to pin at least part of the buffer to
69 		 * get de-tiled view.  For now just reject it.
70 		 */
71 		return -ENOMEM;
72 	}
73 	/* make sure we have the pages: */
74 	return omap_gem_get_pages(obj, &pages, true);
75 }
76 
77 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
78 					  enum dma_data_direction dir)
79 {
80 	struct drm_gem_object *obj = buffer->priv;
81 	omap_gem_put_pages(obj);
82 	return 0;
83 }
84 
85 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
86 		unsigned long page_num)
87 {
88 	struct drm_gem_object *obj = buffer->priv;
89 	struct page **pages;
90 	omap_gem_get_pages(obj, &pages, false);
91 	omap_gem_cpu_sync_page(obj, page_num);
92 	return kmap(pages[page_num]);
93 }
94 
95 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
96 		unsigned long page_num, void *addr)
97 {
98 	struct drm_gem_object *obj = buffer->priv;
99 	struct page **pages;
100 	omap_gem_get_pages(obj, &pages, false);
101 	kunmap(pages[page_num]);
102 }
103 
104 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
105 		struct vm_area_struct *vma)
106 {
107 	struct drm_gem_object *obj = buffer->priv;
108 	int ret = 0;
109 
110 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
111 	if (ret < 0)
112 		return ret;
113 
114 	return omap_gem_mmap_obj(obj, vma);
115 }
116 
117 static const struct dma_buf_ops omap_dmabuf_ops = {
118 	.map_dma_buf = omap_gem_map_dma_buf,
119 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
120 	.release = drm_gem_dmabuf_release,
121 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
122 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
123 	.map = omap_gem_dmabuf_kmap,
124 	.unmap = omap_gem_dmabuf_kunmap,
125 	.mmap = omap_gem_dmabuf_mmap,
126 };
127 
128 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
129 		struct drm_gem_object *obj, int flags)
130 {
131 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
132 
133 	exp_info.ops = &omap_dmabuf_ops;
134 	exp_info.size = obj->size;
135 	exp_info.flags = flags;
136 	exp_info.priv = obj;
137 
138 	return drm_gem_dmabuf_export(dev, &exp_info);
139 }
140 
141 /* -----------------------------------------------------------------------------
142  * DMABUF Import
143  */
144 
145 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
146 					     struct dma_buf *dma_buf)
147 {
148 	struct dma_buf_attachment *attach;
149 	struct drm_gem_object *obj;
150 	struct sg_table *sgt;
151 	int ret;
152 
153 	if (dma_buf->ops == &omap_dmabuf_ops) {
154 		obj = dma_buf->priv;
155 		if (obj->dev == dev) {
156 			/*
157 			 * Importing dmabuf exported from out own gem increases
158 			 * refcount on gem itself instead of f_count of dmabuf.
159 			 */
160 			drm_gem_object_get(obj);
161 			return obj;
162 		}
163 	}
164 
165 	attach = dma_buf_attach(dma_buf, dev->dev);
166 	if (IS_ERR(attach))
167 		return ERR_CAST(attach);
168 
169 	get_dma_buf(dma_buf);
170 
171 	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
172 	if (IS_ERR(sgt)) {
173 		ret = PTR_ERR(sgt);
174 		goto fail_detach;
175 	}
176 
177 	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
178 	if (IS_ERR(obj)) {
179 		ret = PTR_ERR(obj);
180 		goto fail_unmap;
181 	}
182 
183 	obj->import_attach = attach;
184 
185 	return obj;
186 
187 fail_unmap:
188 	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
189 fail_detach:
190 	dma_buf_detach(dma_buf, attach);
191 	dma_buf_put(dma_buf);
192 
193 	return ERR_PTR(ret);
194 }
195