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         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
  70         if (ret < 0)
  71                 return ret;
  72
  73         return omap_gem_mmap_obj(obj, vma);
  74 }
  75
  76 static const struct dma_buf_ops omap_dmabuf_ops = {
  77         .map_dma_buf = omap_gem_map_dma_buf,
  78         .unmap_dma_buf = omap_gem_unmap_dma_buf,
  79         .release = drm_gem_dmabuf_release,
  80         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
  81         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
  82         .mmap = omap_gem_dmabuf_mmap,
  83 };
  84
  85 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
  86 {
  87         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  88
  89         exp_info.ops = &omap_dmabuf_ops;
  90         exp_info.size = omap_gem_mmap_size(obj);
  91         exp_info.flags = flags;
  92         exp_info.priv = obj;
  93         exp_info.resv = obj->resv;
  94
  95         return drm_gem_dmabuf_export(obj->dev, &exp_info);
  96 }
  97
  98 /* -----------------------------------------------------------------------------
  99  * DMABUF Import
 100  */
 101
 102 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 103                                              struct dma_buf *dma_buf)
 104 {
 105         struct dma_buf_attachment *attach;
 106         struct drm_gem_object *obj;
 107         struct sg_table *sgt;
 108         int ret;
 109
 110         if (dma_buf->ops == &omap_dmabuf_ops) {
 111                 obj = dma_buf->priv;
 112                 if (obj->dev == dev) {
 113                         /*
 114                          * Importing dmabuf exported from out own gem increases
 115                          * refcount on gem itself instead of f_count of dmabuf.
 116                          */
 117                         drm_gem_object_get(obj);
 118                         return obj;
 119                 }
 120         }
 121
 122         attach = dma_buf_attach(dma_buf, dev->dev);
 123         if (IS_ERR(attach))
 124                 return ERR_CAST(attach);
 125
 126         get_dma_buf(dma_buf);
 127
 128         sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
 129         if (IS_ERR(sgt)) {
 130                 ret = PTR_ERR(sgt);
 131                 goto fail_detach;
 132         }
 133
 134         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 135         if (IS_ERR(obj)) {
 136                 ret = PTR_ERR(obj);
 137                 goto fail_unmap;
 138         }
 139
 140         obj->import_attach = attach;
 141
 142         return obj;
 143
 144 fail_unmap:
 145         dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
 146 fail_detach:
 147         dma_buf_detach(dma_buf, attach);
 148         dma_buf_put(dma_buf);
 149
 150         return ERR_PTR(ret);
 151 }