1/* exynos_drm_dmabuf.c
  2 *
  3 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
  4 * Author: Inki Dae <inki.dae@samsung.com>
  5 *
  6 * This program is free software; you can redistribute  it and/or modify it
  7 * under  the terms of  the GNU General  Public License as published by the
  8 * Free Software Foundation;  either version 2 of the  License, or (at your
  9 * option) any later version.
 10 */
 11
 12#include <drm/drmP.h>
 13#include <drm/exynos_drm.h>
 14#include "exynos_drm_dmabuf.h"
 15#include "exynos_drm_drv.h"
 16#include "exynos_drm_gem.h"
 17
 18#include <linux/dma-buf.h>
 19
 20struct exynos_drm_dmabuf_attachment {
 21	struct sg_table sgt;
 22	enum dma_data_direction dir;
 23	bool is_mapped;
 24};
 25
 26static struct exynos_drm_gem_obj *dma_buf_to_obj(struct dma_buf *buf)
 27{
 28	return to_exynos_gem_obj(buf->priv);
 29}
 30
 31static int exynos_gem_attach_dma_buf(struct dma_buf *dmabuf,
 32					struct device *dev,
 33					struct dma_buf_attachment *attach)
 34{
 35	struct exynos_drm_dmabuf_attachment *exynos_attach;
 36
 37	exynos_attach = kzalloc(sizeof(*exynos_attach), GFP_KERNEL);
 38	if (!exynos_attach)
 39		return -ENOMEM;
 40
 41	exynos_attach->dir = DMA_NONE;
 42	attach->priv = exynos_attach;
 43
 44	return 0;
 45}
 46
 47static void exynos_gem_detach_dma_buf(struct dma_buf *dmabuf,
 48					struct dma_buf_attachment *attach)
 49{
 50	struct exynos_drm_dmabuf_attachment *exynos_attach = attach->priv;
 51	struct sg_table *sgt;
 52
 53	if (!exynos_attach)
 54		return;
 55
 56	sgt = &exynos_attach->sgt;
 57
 58	if (exynos_attach->dir != DMA_NONE)
 59		dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
 60				exynos_attach->dir);
 61
 62	sg_free_table(sgt);
 63	kfree(exynos_attach);
 64	attach->priv = NULL;
 65}
 66
 67static struct sg_table *
 68		exynos_gem_map_dma_buf(struct dma_buf_attachment *attach,
 69					enum dma_data_direction dir)
 70{
 71	struct exynos_drm_dmabuf_attachment *exynos_attach = attach->priv;
 72	struct exynos_drm_gem_obj *gem_obj = dma_buf_to_obj(attach->dmabuf);
 73	struct drm_device *dev = gem_obj->base.dev;
 74	struct exynos_drm_gem_buf *buf;
 75	struct scatterlist *rd, *wr;
 76	struct sg_table *sgt = NULL;
 77	unsigned int i;
 78	int nents, ret;
 79
 80	/* just return current sgt if already requested. */
 81	if (exynos_attach->dir == dir && exynos_attach->is_mapped)
 82		return &exynos_attach->sgt;
 83
 84	buf = gem_obj->buffer;
 85	if (!buf) {
 86		DRM_ERROR("buffer is null.\n");
 87		return ERR_PTR(-ENOMEM);
 88	}
 89
 90	sgt = &exynos_attach->sgt;
 91
 92	ret = sg_alloc_table(sgt, buf->sgt->orig_nents, GFP_KERNEL);
 93	if (ret) {
 94		DRM_ERROR("failed to alloc sgt.\n");
 95		return ERR_PTR(-ENOMEM);
 96	}
 97
 98	mutex_lock(&dev->struct_mutex);
 99
100	rd = buf->sgt->sgl;
101	wr = sgt->sgl;
102	for (i = 0; i < sgt->orig_nents; ++i) {
103		sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
104		rd = sg_next(rd);
105		wr = sg_next(wr);
106	}
107
108	if (dir != DMA_NONE) {
109		nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);
110		if (!nents) {
111			DRM_ERROR("failed to map sgl with iommu.\n");
112			sg_free_table(sgt);
113			sgt = ERR_PTR(-EIO);
114			goto err_unlock;
115		}
116	}
117
118	exynos_attach->is_mapped = true;
119	exynos_attach->dir = dir;
120	attach->priv = exynos_attach;
121
122	DRM_DEBUG_PRIME("buffer size = 0x%lx\n", buf->size);
123
124err_unlock:
125	mutex_unlock(&dev->struct_mutex);
126	return sgt;
127}
128
129static void exynos_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
130						struct sg_table *sgt,
131						enum dma_data_direction dir)
132{
133	/* Nothing to do. */
134}
135
136static void *exynos_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
137						unsigned long page_num)
138{
139	/* TODO */
140
141	return NULL;
142}
143
144static void exynos_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
145						unsigned long page_num,
146						void *addr)
147{
148	/* TODO */
149}
150
151static void *exynos_gem_dmabuf_kmap(struct dma_buf *dma_buf,
152					unsigned long page_num)
153{
154	/* TODO */
155
156	return NULL;
157}
158
159static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
160					unsigned long page_num, void *addr)
161{
162	/* TODO */
163}
164
165static int exynos_gem_dmabuf_mmap(struct dma_buf *dma_buf,
166	struct vm_area_struct *vma)
167{
168	return -ENOTTY;
169}
170
171static struct dma_buf_ops exynos_dmabuf_ops = {
172	.attach			= exynos_gem_attach_dma_buf,
173	.detach			= exynos_gem_detach_dma_buf,
174	.map_dma_buf		= exynos_gem_map_dma_buf,
175	.unmap_dma_buf		= exynos_gem_unmap_dma_buf,
176	.kmap			= exynos_gem_dmabuf_kmap,
177	.kmap_atomic		= exynos_gem_dmabuf_kmap_atomic,
178	.kunmap			= exynos_gem_dmabuf_kunmap,
179	.kunmap_atomic		= exynos_gem_dmabuf_kunmap_atomic,
180	.mmap			= exynos_gem_dmabuf_mmap,
181	.release		= drm_gem_dmabuf_release,
182};
183
184struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
185				struct drm_gem_object *obj, int flags)
186{
187	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
188
189	return dma_buf_export(obj, &exynos_dmabuf_ops,
190				exynos_gem_obj->base.size, flags);
191}
192
193struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
194				struct dma_buf *dma_buf)
195{
196	struct dma_buf_attachment *attach;
197	struct sg_table *sgt;
198	struct scatterlist *sgl;
199	struct exynos_drm_gem_obj *exynos_gem_obj;
200	struct exynos_drm_gem_buf *buffer;
201	int ret;
202
203	/* is this one of own objects? */
204	if (dma_buf->ops == &exynos_dmabuf_ops) {
205		struct drm_gem_object *obj;
206
207		obj = dma_buf->priv;
208
209		/* is it from our device? */
210		if (obj->dev == drm_dev) {
211			/*
212			 * Importing dmabuf exported from out own gem increases
213			 * refcount on gem itself instead of f_count of dmabuf.
214			 */
215			drm_gem_object_reference(obj);
216			return obj;
217		}
218	}
219
220	attach = dma_buf_attach(dma_buf, drm_dev->dev);
221	if (IS_ERR(attach))
222		return ERR_PTR(-EINVAL);
223
224	get_dma_buf(dma_buf);
225
226	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
227	if (IS_ERR(sgt)) {
228		ret = PTR_ERR(sgt);
229		goto err_buf_detach;
230	}
231
232	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
233	if (!buffer) {
234		ret = -ENOMEM;
235		goto err_unmap_attach;
236	}
237
238	exynos_gem_obj = exynos_drm_gem_init(drm_dev, dma_buf->size);
239	if (!exynos_gem_obj) {
240		ret = -ENOMEM;
241		goto err_free_buffer;
242	}
243
244	sgl = sgt->sgl;
245
246	buffer->size = dma_buf->size;
247	buffer->dma_addr = sg_dma_address(sgl);
248
249	if (sgt->nents == 1) {
250		/* always physically continuous memory if sgt->nents is 1. */
251		exynos_gem_obj->flags |= EXYNOS_BO_CONTIG;
252	} else {
253		/*
254		 * this case could be CONTIG or NONCONTIG type but for now
255		 * sets NONCONTIG.
256		 * TODO. we have to find a way that exporter can notify
257		 * the type of its own buffer to importer.
258		 */
259		exynos_gem_obj->flags |= EXYNOS_BO_NONCONTIG;
260	}
261
262	exynos_gem_obj->buffer = buffer;
263	buffer->sgt = sgt;
264	exynos_gem_obj->base.import_attach = attach;
265
266	DRM_DEBUG_PRIME("dma_addr = %pad, size = 0x%lx\n", &buffer->dma_addr,
267								buffer->size);
268
269	return &exynos_gem_obj->base;
270
271err_free_buffer:
272	kfree(buffer);
273	buffer = NULL;
274err_unmap_attach:
275	dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
276err_buf_detach:
277	dma_buf_detach(dma_buf, attach);
278	dma_buf_put(dma_buf);
279
280	return ERR_PTR(ret);
281}
282
283MODULE_AUTHOR("Inki Dae <inki.dae@samsung.com>");
284MODULE_DESCRIPTION("Samsung SoC DRM DMABUF Module");
285MODULE_LICENSE("GPL");