drivers/gpu/drm/exynos/exynos_drm_dmabuf.c

   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
  20 struct exynos_drm_dmabuf_attachment {
  21         struct sg_table sgt;
  22         enum dma_data_direction dir;
  23         bool is_mapped;
  24 };
  25
  26 static struct exynos_drm_gem_obj *dma_buf_to_obj(struct dma_buf *buf)
  27 {
  28         return to_exynos_gem_obj(buf->priv);
  29 }
  30
  31 static 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
  47 static 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
  67 static 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
 124 err_unlock:
 125         mutex_unlock(&dev->struct_mutex);
 126         return sgt;
 127 }
 128
 129 static 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
 136 static 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
 144 static void exynos_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
 145                                                 unsigned long page_num,
 146                                                 void *addr)
 147 {
 148         /* TODO */
 149 }
 150
 151 static void *exynos_gem_dmabuf_kmap(struct dma_buf *dma_buf,
 152                                         unsigned long page_num)
 153 {
 154         /* TODO */
 155
 156         return NULL;
 157 }
 158
 159 static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
 160                                         unsigned long page_num, void *addr)
 161 {
 162         /* TODO */
 163 }
 164
 165 static int exynos_gem_dmabuf_mmap(struct dma_buf *dma_buf,
 166         struct vm_area_struct *vma)
 167 {
 168         return -ENOTTY;
 169 }
 170
 171 static 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
 184 struct 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
 193 struct 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
 271 err_free_buffer:
 272         kfree(buffer);
 273         buffer = NULL;
 274 err_unmap_attach:
 275         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 276 err_buf_detach:
 277         dma_buf_detach(dma_buf, attach);
 278         dma_buf_put(dma_buf);
 279
 280         return ERR_PTR(ret);
 281 }
 282
 283 MODULE_AUTHOR("Inki Dae <inki.dae@samsung.com>");
 284 MODULE_DESCRIPTION("Samsung SoC DRM DMABUF Module");
 285 MODULE_LICENSE("GPL");