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 <rob.clark@linaro.org>
   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
  68         return drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
  69 }
  70
  71 static const struct dma_buf_ops omap_dmabuf_ops = {
  72         .map_dma_buf = omap_gem_map_dma_buf,
  73         .unmap_dma_buf = omap_gem_unmap_dma_buf,
  74         .release = drm_gem_dmabuf_release,
  75         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
  76         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
  77         .mmap = omap_gem_dmabuf_mmap,
  78 };
  79
  80 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
  81 {
  82         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  83
  84         exp_info.ops = &omap_dmabuf_ops;
  85         exp_info.size = omap_gem_mmap_size(obj);
  86         exp_info.flags = flags;
  87         exp_info.priv = obj;
  88         exp_info.resv = obj->resv;
  89
  90         return drm_gem_dmabuf_export(obj->dev, &exp_info);
  91 }
  92
  93 /* -----------------------------------------------------------------------------
  94  * DMABUF Import
  95  */
  96
  97 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
  98                                              struct dma_buf *dma_buf)
  99 {
 100         struct dma_buf_attachment *attach;
 101         struct drm_gem_object *obj;
 102         struct sg_table *sgt;
 103         int ret;
 104
 105         if (dma_buf->ops == &omap_dmabuf_ops) {
 106                 obj = dma_buf->priv;
 107                 if (obj->dev == dev) {
 108                         /*
 109                          * Importing dmabuf exported from out own gem increases
 110                          * refcount on gem itself instead of f_count of dmabuf.
 111                          */
 112                         drm_gem_object_get(obj);
 113                         return obj;
 114                 }
 115         }
 116
 117         attach = dma_buf_attach(dma_buf, dev->dev);
 118         if (IS_ERR(attach))
 119                 return ERR_CAST(attach);
 120
 121         get_dma_buf(dma_buf);
 122
 123         sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
 124         if (IS_ERR(sgt)) {
 125                 ret = PTR_ERR(sgt);
 126                 goto fail_detach;
 127         }
 128
 129         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 130         if (IS_ERR(obj)) {
 131                 ret = PTR_ERR(obj);
 132                 goto fail_unmap;
 133         }
 134
 135         obj->import_attach = attach;
 136
 137         return obj;
 138
 139 fail_unmap:
 140         dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
 141 fail_detach:
 142         dma_buf_detach(dma_buf, attach);
 143         dma_buf_put(dma_buf);
 144
 145         return ERR_PTR(ret);
 146 }