drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright © 2016 Intel Corporation
   5  */
   6
   7 #include "mock_dmabuf.h"
   8
   9 static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment,
  10                                          enum dma_data_direction dir)
  11 {
  12         struct mock_dmabuf *mock = to_mock(attachment->dmabuf);
  13         struct sg_table *st;
  14         struct scatterlist *sg;
  15         int i, err;
  16
  17         st = kmalloc(sizeof(*st), GFP_KERNEL);
  18         if (!st)
  19                 return ERR_PTR(-ENOMEM);
  20
  21         err = sg_alloc_table(st, mock->npages, GFP_KERNEL);
  22         if (err)
  23                 goto err_free;
  24
  25         sg = st->sgl;
  26         for (i = 0; i < mock->npages; i++) {
  27                 sg_set_page(sg, mock->pages[i], PAGE_SIZE, 0);
  28                 sg = sg_next(sg);
  29         }
  30
  31         err = dma_map_sgtable(attachment->dev, st, dir, 0);
  32         if (err)
  33                 goto err_st;
  34
  35         return st;
  36
  37 err_st:
  38         sg_free_table(st);
  39 err_free:
  40         kfree(st);
  41         return ERR_PTR(err);
  42 }
  43
  44 static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment,
  45                                struct sg_table *st,
  46                                enum dma_data_direction dir)
  47 {
  48         dma_unmap_sgtable(attachment->dev, st, dir, 0);
  49         sg_free_table(st);
  50         kfree(st);
  51 }
  52
  53 static void mock_dmabuf_release(struct dma_buf *dma_buf)
  54 {
  55         struct mock_dmabuf *mock = to_mock(dma_buf);
  56         int i;
  57
  58         for (i = 0; i < mock->npages; i++)
  59                 put_page(mock->pages[i]);
  60
  61         kfree(mock);
  62 }
  63
  64 static void *mock_dmabuf_vmap(struct dma_buf *dma_buf)
  65 {
  66         struct mock_dmabuf *mock = to_mock(dma_buf);
  67
  68         return vm_map_ram(mock->pages, mock->npages, 0);
  69 }
  70
  71 static void mock_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
  72 {
  73         struct mock_dmabuf *mock = to_mock(dma_buf);
  74
  75         vm_unmap_ram(vaddr, mock->npages);
  76 }
  77
  78 static int mock_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
  79 {
  80         return -ENODEV;
  81 }
  82
  83 static const struct dma_buf_ops mock_dmabuf_ops =  {
  84         .map_dma_buf = mock_map_dma_buf,
  85         .unmap_dma_buf = mock_unmap_dma_buf,
  86         .release = mock_dmabuf_release,
  87         .mmap = mock_dmabuf_mmap,
  88         .vmap = mock_dmabuf_vmap,
  89         .vunmap = mock_dmabuf_vunmap,
  90 };
  91
  92 static struct dma_buf *mock_dmabuf(int npages)
  93 {
  94         struct mock_dmabuf *mock;
  95         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  96         struct dma_buf *dmabuf;
  97         int i;
  98
  99         mock = kmalloc(sizeof(*mock) + npages * sizeof(struct page *),
 100                        GFP_KERNEL);
 101         if (!mock)
 102                 return ERR_PTR(-ENOMEM);
 103
 104         mock->npages = npages;
 105         for (i = 0; i < npages; i++) {
 106                 mock->pages[i] = alloc_page(GFP_KERNEL);
 107                 if (!mock->pages[i])
 108                         goto err;
 109         }
 110
 111         exp_info.ops = &mock_dmabuf_ops;
 112         exp_info.size = npages * PAGE_SIZE;
 113         exp_info.flags = O_CLOEXEC;
 114         exp_info.priv = mock;
 115
 116         dmabuf = dma_buf_export(&exp_info);
 117         if (IS_ERR(dmabuf))
 118                 goto err;
 119
 120         return dmabuf;
 121
 122 err:
 123         while (i--)
 124                 put_page(mock->pages[i]);
 125         kfree(mock);
 126         return ERR_PTR(-ENOMEM);
 127 }