drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2011 Texas Instruments Incorporated - http://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 /* -----------------------------------------------------------------------------
  15  * DMABUF Export
  16  */
  17
  18 static struct sg_table *omap_gem_map_dma_buf(
  19                 struct dma_buf_attachment *attachment,
  20                 enum dma_data_direction dir)
  21 {
  22         struct drm_gem_object *obj = attachment->dmabuf->priv;
  23         struct sg_table *sg;
  24         dma_addr_t dma_addr;
  25         int ret;
  26
  27         sg = kzalloc(sizeof(*sg), GFP_KERNEL);
  28         if (!sg)
  29                 return ERR_PTR(-ENOMEM);
  30
  31         /* camera, etc, need physically contiguous.. but we need a
  32          * better way to know this..
  33          */
  34         ret = omap_gem_pin(obj, &dma_addr);
  35         if (ret)
  36                 goto out;
  37
  38         ret = sg_alloc_table(sg, 1, GFP_KERNEL);
  39         if (ret)
  40                 goto out;
  41
  42         sg_init_table(sg->sgl, 1);
  43         sg_dma_len(sg->sgl) = obj->size;
  44         sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
  45         sg_dma_address(sg->sgl) = dma_addr;
  46
  47         /* this must be after omap_gem_pin() to ensure we have pages attached */
  48         omap_gem_dma_sync_buffer(obj, dir);
  49
  50         return sg;
  51 out:
  52         kfree(sg);
  53         return ERR_PTR(ret);
  54 }
  55
  56 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  57                 struct sg_table *sg, enum dma_data_direction dir)
  58 {
  59         struct drm_gem_object *obj = attachment->dmabuf->priv;
  60         omap_gem_unpin(obj);
  61         sg_free_table(sg);
  62         kfree(sg);
  63 }
  64
  65 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
  66                 enum dma_data_direction dir)
  67 {
  68         struct drm_gem_object *obj = buffer->priv;
  69         struct page **pages;
  70         if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
  71                 /* TODO we would need to pin at least part of the buffer to
  72                  * get de-tiled view.  For now just reject it.
  73                  */
  74                 return -ENOMEM;
  75         }
  76         /* make sure we have the pages: */
  77         return omap_gem_get_pages(obj, &pages, true);
  78 }
  79
  80 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
  81                                           enum dma_data_direction dir)
  82 {
  83         struct drm_gem_object *obj = buffer->priv;
  84         omap_gem_put_pages(obj);
  85         return 0;
  86 }
  87
  88 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
  89                 struct vm_area_struct *vma)
  90 {
  91         struct drm_gem_object *obj = buffer->priv;
  92         int ret = 0;
  93
  94         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
  95         if (ret < 0)
  96                 return ret;
  97
  98         return omap_gem_mmap_obj(obj, vma);
  99 }
 100
 101 static const struct dma_buf_ops omap_dmabuf_ops = {
 102         .map_dma_buf = omap_gem_map_dma_buf,
 103         .unmap_dma_buf = omap_gem_unmap_dma_buf,
 104         .release = drm_gem_dmabuf_release,
 105         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 106         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
 107         .mmap = omap_gem_dmabuf_mmap,
 108 };
 109
 110 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
 111 {
 112         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 113
 114         exp_info.ops = &omap_dmabuf_ops;
 115         exp_info.size = obj->size;
 116         exp_info.flags = flags;
 117         exp_info.priv = obj;
 118
 119         return drm_gem_dmabuf_export(obj->dev, &exp_info);
 120 }
 121
 122 /* -----------------------------------------------------------------------------
 123  * DMABUF Import
 124  */
 125
 126 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 127                                              struct dma_buf *dma_buf)
 128 {
 129         struct dma_buf_attachment *attach;
 130         struct drm_gem_object *obj;
 131         struct sg_table *sgt;
 132         int ret;
 133
 134         if (dma_buf->ops == &omap_dmabuf_ops) {
 135                 obj = dma_buf->priv;
 136                 if (obj->dev == dev) {
 137                         /*
 138                          * Importing dmabuf exported from out own gem increases
 139                          * refcount on gem itself instead of f_count of dmabuf.
 140                          */
 141                         drm_gem_object_get(obj);
 142                         return obj;
 143                 }
 144         }
 145
 146         attach = dma_buf_attach(dma_buf, dev->dev);
 147         if (IS_ERR(attach))
 148                 return ERR_CAST(attach);
 149
 150         get_dma_buf(dma_buf);
 151
 152         sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
 153         if (IS_ERR(sgt)) {
 154                 ret = PTR_ERR(sgt);
 155                 goto fail_detach;
 156         }
 157
 158         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 159         if (IS_ERR(obj)) {
 160                 ret = PTR_ERR(obj);
 161                 goto fail_unmap;
 162         }
 163
 164         obj->import_attach = attach;
 165
 166         return obj;
 167
 168 fail_unmap:
 169         dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
 170 fail_detach:
 171         dma_buf_detach(dma_buf, attach);
 172         dma_buf_put(dma_buf);
 173
 174         return ERR_PTR(ret);
 175 }