drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
   4  * Author: Rob Clark <[email protected]>
   5  */
   6
   7 #include <linux/dma-buf.h>
   8 #include <linux/highmem.h>
   9
  10 #include <drm/drm_prime.h>
  11
  12 #include "omap_drv.h"
  13
  14 MODULE_IMPORT_NS(DMA_BUF);
  15
  16 /* -----------------------------------------------------------------------------
  17  * DMABUF Export
  18  */
  19
  20 static struct sg_table *omap_gem_map_dma_buf(
  21                 struct dma_buf_attachment *attachment,
  22                 enum dma_data_direction dir)
  23 {
  24         struct drm_gem_object *obj = attachment->dmabuf->priv;
  25         struct sg_table *sg;
  26         sg = omap_gem_get_sg(obj, dir);
  27         if (IS_ERR(sg))
  28                 return sg;
  29
  30         return sg;
  31 }
  32
  33 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  34                 struct sg_table *sg, enum dma_data_direction dir)
  35 {
  36         struct drm_gem_object *obj = attachment->dmabuf->priv;
  37         omap_gem_put_sg(obj, sg);
  38 }
  39
  40 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
  41                 enum dma_data_direction dir)
  42 {
  43         struct drm_gem_object *obj = buffer->priv;
  44         struct page **pages;
  45         if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
  46                 /* TODO we would need to pin at least part of the buffer to
  47                  * get de-tiled view.  For now just reject it.
  48                  */
  49                 return -ENOMEM;
  50         }
  51         /* make sure we have the pages: */
  52         return omap_gem_get_pages(obj, &pages, true);
  53 }
  54
  55 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
  56                                           enum dma_data_direction dir)
  57 {
  58         struct drm_gem_object *obj = buffer->priv;
  59         omap_gem_put_pages(obj);
  60         return 0;
  61 }
  62
  63 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
  64                 struct vm_area_struct *vma)
  65 {
  66         struct drm_gem_object *obj = buffer->priv;
  67         int ret = 0;
  68
  69         dma_resv_assert_held(buffer->resv);
  70
  71         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
  72         if (ret < 0)
  73                 return ret;
  74
  75         return omap_gem_mmap_obj(obj, vma);
  76 }
  77
  78 static const struct dma_buf_ops omap_dmabuf_ops = {
  79         .map_dma_buf = omap_gem_map_dma_buf,
  80         .unmap_dma_buf = omap_gem_unmap_dma_buf,
  81         .release = drm_gem_dmabuf_release,
  82         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
  83         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
  84         .mmap = omap_gem_dmabuf_mmap,
  85 };
  86
  87 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
  88 {
  89         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  90
  91         exp_info.ops = &omap_dmabuf_ops;
  92         exp_info.size = omap_gem_mmap_size(obj);
  93         exp_info.flags = flags;
  94         exp_info.priv = obj;
  95         exp_info.resv = obj->resv;
  96
  97         return drm_gem_dmabuf_export(obj->dev, &exp_info);
  98 }
  99
 100 /* -----------------------------------------------------------------------------
 101  * DMABUF Import
 102  */
 103
 104 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 105                                              struct dma_buf *dma_buf)
 106 {
 107         struct dma_buf_attachment *attach;
 108         struct drm_gem_object *obj;
 109         struct sg_table *sgt;
 110         int ret;
 111
 112         if (dma_buf->ops == &omap_dmabuf_ops) {
 113                 obj = dma_buf->priv;
 114                 if (obj->dev == dev) {
 115                         /*
 116                          * Importing dmabuf exported from out own gem increases
 117                          * refcount on gem itself instead of f_count of dmabuf.
 118                          */
 119                         drm_gem_object_get(obj);
 120                         return obj;
 121                 }
 122         }
 123
 124         attach = dma_buf_attach(dma_buf, dev->dev);
 125         if (IS_ERR(attach))
 126                 return ERR_CAST(attach);
 127
 128         get_dma_buf(dma_buf);
 129
 130         sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
 131         if (IS_ERR(sgt)) {
 132                 ret = PTR_ERR(sgt);
 133                 goto fail_detach;
 134         }
 135
 136         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 137         if (IS_ERR(obj)) {
 138                 ret = PTR_ERR(obj);
 139                 goto fail_unmap;
 140         }
 141
 142         obj->import_attach = attach;
 143
 144         return obj;
 145
 146 fail_unmap:
 147         dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
 148 fail_detach:
 149         dma_buf_detach(dma_buf, attach);
 150         dma_buf_put(dma_buf);
 151
 152         return ERR_PTR(ret);
 153 }