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);
  27         if (IS_ERR(sg))
  28                 return sg;
  29
  30         /* this must be after omap_gem_pin() to ensure we have pages attached */
  31         omap_gem_dma_sync_buffer(obj, dir);
  32
  33         return sg;
  34 }
  35
  36 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  37                 struct sg_table *sg, enum dma_data_direction dir)
  38 {
  39         struct drm_gem_object *obj = attachment->dmabuf->priv;
  40         omap_gem_put_sg(obj, sg);
  41 }
  42
  43 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
  44                 enum dma_data_direction dir)
  45 {
  46         struct drm_gem_object *obj = buffer->priv;
  47         struct page **pages;
  48         if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
  49                 /* TODO we would need to pin at least part of the buffer to
  50                  * get de-tiled view.  For now just reject it.
  51                  */
  52                 return -ENOMEM;
  53         }
  54         /* make sure we have the pages: */
  55         return omap_gem_get_pages(obj, &pages, true);
  56 }
  57
  58 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
  59                                           enum dma_data_direction dir)
  60 {
  61         struct drm_gem_object *obj = buffer->priv;
  62         omap_gem_put_pages(obj);
  63         return 0;
  64 }
  65
  66 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
  67                 struct vm_area_struct *vma)
  68 {
  69         struct drm_gem_object *obj = buffer->priv;
  70         int ret = 0;
  71
  72         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
  73         if (ret < 0)
  74                 return ret;
  75
  76         return omap_gem_mmap_obj(obj, vma);
  77 }
  78
  79 static const struct dma_buf_ops omap_dmabuf_ops = {
  80         .map_dma_buf = omap_gem_map_dma_buf,
  81         .unmap_dma_buf = omap_gem_unmap_dma_buf,
  82         .release = drm_gem_dmabuf_release,
  83         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
  84         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
  85         .mmap = omap_gem_dmabuf_mmap,
  86 };
  87
  88 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
  89 {
  90         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  91
  92         exp_info.ops = &omap_dmabuf_ops;
  93         exp_info.size = omap_gem_mmap_size(obj);
  94         exp_info.flags = flags;
  95         exp_info.priv = obj;
  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(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(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 }