drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2012 Red Hat Inc
   5  */
   6
   7 #include <linux/dma-buf.h>
   8 #include <linux/highmem.h>
   9 #include <linux/dma-resv.h>
  10
  11 #include "i915_drv.h"
  12 #include "i915_gem_object.h"
  13 #include "i915_scatterlist.h"
  14
  15 static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf)
  16 {
  17         return to_intel_bo(buf->priv);
  18 }
  19
  20 static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
  21                                              enum dma_data_direction dir)
  22 {
  23         struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
  24         struct sg_table *st;
  25         struct scatterlist *src, *dst;
  26         int ret, i;
  27
  28         ret = i915_gem_object_pin_pages_unlocked(obj);
  29         if (ret)
  30                 goto err;
  31
  32         /* Copy sg so that we make an independent mapping */
  33         st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
  34         if (st == NULL) {
  35                 ret = -ENOMEM;
  36                 goto err_unpin_pages;
  37         }
  38
  39         ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL);
  40         if (ret)
  41                 goto err_free;
  42
  43         src = obj->mm.pages->sgl;
  44         dst = st->sgl;
  45         for (i = 0; i < obj->mm.pages->nents; i++) {
  46                 sg_set_page(dst, sg_page(src), src->length, 0);
  47                 dst = sg_next(dst);
  48                 src = sg_next(src);
  49         }
  50
  51         ret = dma_map_sgtable(attachment->dev, st, dir, DMA_ATTR_SKIP_CPU_SYNC);
  52         if (ret)
  53                 goto err_free_sg;
  54
  55         return st;
  56
  57 err_free_sg:
  58         sg_free_table(st);
  59 err_free:
  60         kfree(st);
  61 err_unpin_pages:
  62         i915_gem_object_unpin_pages(obj);
  63 err:
  64         return ERR_PTR(ret);
  65 }
  66
  67 static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  68                                    struct sg_table *sg,
  69                                    enum dma_data_direction dir)
  70 {
  71         struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
  72
  73         dma_unmap_sgtable(attachment->dev, sg, dir, DMA_ATTR_SKIP_CPU_SYNC);
  74         sg_free_table(sg);
  75         kfree(sg);
  76
  77         i915_gem_object_unpin_pages(obj);
  78 }
  79
  80 static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
  81 {
  82         struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
  83         void *vaddr;
  84
  85         vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
  86         if (IS_ERR(vaddr))
  87                 return PTR_ERR(vaddr);
  88
  89         dma_buf_map_set_vaddr(map, vaddr);
  90
  91         return 0;
  92 }
  93
  94 static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
  95 {
  96         struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
  97
  98         i915_gem_object_flush_map(obj);
  99         i915_gem_object_unpin_map(obj);
 100 }
 101
 102 static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
 103 {
 104         struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
 105         int ret;
 106
 107         if (obj->base.size < vma->vm_end - vma->vm_start)
 108                 return -EINVAL;
 109
 110         if (!obj->base.filp)
 111                 return -ENODEV;
 112
 113         ret = call_mmap(obj->base.filp, vma);
 114         if (ret)
 115                 return ret;
 116
 117         vma_set_file(vma, obj->base.filp);
 118
 119         return 0;
 120 }
 121
 122 static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
 123 {
 124         struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
 125         bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
 126         struct i915_gem_ww_ctx ww;
 127         int err;
 128
 129         i915_gem_ww_ctx_init(&ww, true);
 130 retry:
 131         err = i915_gem_object_lock(obj, &ww);
 132         if (!err)
 133                 err = i915_gem_object_pin_pages(obj);
 134         if (!err) {
 135                 err = i915_gem_object_set_to_cpu_domain(obj, write);
 136                 i915_gem_object_unpin_pages(obj);
 137         }
 138         if (err == -EDEADLK) {
 139                 err = i915_gem_ww_ctx_backoff(&ww);
 140                 if (!err)
 141                         goto retry;
 142         }
 143         i915_gem_ww_ctx_fini(&ww);
 144         return err;
 145 }
 146
 147 static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
 148 {
 149         struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
 150         struct i915_gem_ww_ctx ww;
 151         int err;
 152
 153         i915_gem_ww_ctx_init(&ww, true);
 154 retry:
 155         err = i915_gem_object_lock(obj, &ww);
 156         if (!err)
 157                 err = i915_gem_object_pin_pages(obj);
 158         if (!err) {
 159                 err = i915_gem_object_set_to_gtt_domain(obj, false);
 160                 i915_gem_object_unpin_pages(obj);
 161         }
 162         if (err == -EDEADLK) {
 163                 err = i915_gem_ww_ctx_backoff(&ww);
 164                 if (!err)
 165                         goto retry;
 166         }
 167         i915_gem_ww_ctx_fini(&ww);
 168         return err;
 169 }
 170
 171 static const struct dma_buf_ops i915_dmabuf_ops =  {
 172         .map_dma_buf = i915_gem_map_dma_buf,
 173         .unmap_dma_buf = i915_gem_unmap_dma_buf,
 174         .release = drm_gem_dmabuf_release,
 175         .mmap = i915_gem_dmabuf_mmap,
 176         .vmap = i915_gem_dmabuf_vmap,
 177         .vunmap = i915_gem_dmabuf_vunmap,
 178         .begin_cpu_access = i915_gem_begin_cpu_access,
 179         .end_cpu_access = i915_gem_end_cpu_access,
 180 };
 181
 182 struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
 183 {
 184         struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
 185         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 186
 187         exp_info.ops = &i915_dmabuf_ops;
 188         exp_info.size = gem_obj->size;
 189         exp_info.flags = flags;
 190         exp_info.priv = gem_obj;
 191         exp_info.resv = obj->base.resv;
 192
 193         if (obj->ops->dmabuf_export) {
 194                 int ret = obj->ops->dmabuf_export(obj);
 195                 if (ret)
 196                         return ERR_PTR(ret);
 197         }
 198
 199         return drm_gem_dmabuf_export(gem_obj->dev, &exp_info);
 200 }
 201
 202 static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
 203 {
 204         struct sg_table *pages;
 205         unsigned int sg_page_sizes;
 206
 207         pages = dma_buf_map_attachment(obj->base.import_attach,
 208                                        DMA_BIDIRECTIONAL);
 209         if (IS_ERR(pages))
 210                 return PTR_ERR(pages);
 211
 212         sg_page_sizes = i915_sg_page_sizes(pages->sgl);
 213
 214         __i915_gem_object_set_pages(obj, pages, sg_page_sizes);
 215
 216         return 0;
 217 }
 218
 219 static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,
 220                                              struct sg_table *pages)
 221 {
 222         dma_buf_unmap_attachment(obj->base.import_attach, pages,
 223                                  DMA_BIDIRECTIONAL);
 224 }
 225
 226 static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
 227         .name = "i915_gem_object_dmabuf",
 228         .get_pages = i915_gem_object_get_pages_dmabuf,
 229         .put_pages = i915_gem_object_put_pages_dmabuf,
 230 };
 231
 232 struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
 233                                              struct dma_buf *dma_buf)
 234 {
 235         static struct lock_class_key lock_class;
 236         struct dma_buf_attachment *attach;
 237         struct drm_i915_gem_object *obj;
 238         int ret;
 239
 240         /* is this one of own objects? */
 241         if (dma_buf->ops == &i915_dmabuf_ops) {
 242                 obj = dma_buf_to_obj(dma_buf);
 243                 /* is it from our device? */
 244                 if (obj->base.dev == dev) {
 245                         /*
 246                          * Importing dmabuf exported from out own gem increases
 247                          * refcount on gem itself instead of f_count of dmabuf.
 248                          */
 249                         return &i915_gem_object_get(obj)->base;
 250                 }
 251         }
 252
 253         if (i915_gem_object_size_2big(dma_buf->size))
 254                 return ERR_PTR(-E2BIG);
 255
 256         /* need to attach */
 257         attach = dma_buf_attach(dma_buf, dev->dev);
 258         if (IS_ERR(attach))
 259                 return ERR_CAST(attach);
 260
 261         get_dma_buf(dma_buf);
 262
 263         obj = i915_gem_object_alloc();
 264         if (obj == NULL) {
 265                 ret = -ENOMEM;
 266                 goto fail_detach;
 267         }
 268
 269         drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
 270         i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops, &lock_class, 0);
 271         obj->base.import_attach = attach;
 272         obj->base.resv = dma_buf->resv;
 273
 274         /* We use GTT as shorthand for a coherent domain, one that is
 275          * neither in the GPU cache nor in the CPU cache, where all
 276          * writes are immediately visible in memory. (That's not strictly
 277          * true, but it's close! There are internal buffers such as the
 278          * write-combined buffer or a delay through the chipset for GTT
 279          * writes that do require us to treat GTT as a separate cache domain.)
 280          */
 281         obj->read_domains = I915_GEM_DOMAIN_GTT;
 282         obj->write_domain = 0;
 283
 284         return &obj->base;
 285
 286 fail_detach:
 287         dma_buf_detach(dma_buf, attach);
 288         dma_buf_put(dma_buf);
 289
 290         return ERR_PTR(ret);
 291 }
 292
 293 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 294 #include "selftests/mock_dmabuf.c"
 295 #include "selftests/i915_gem_dmabuf.c"
 296 #endif