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
   9 #include "omap_drv.h"
  10
  11 /* -----------------------------------------------------------------------------
  12  * DMABUF Export
  13  */
  14
  15 static struct sg_table *omap_gem_map_dma_buf(
  16                 struct dma_buf_attachment *attachment,
  17                 enum dma_data_direction dir)
  18 {
  19         struct drm_gem_object *obj = attachment->dmabuf->priv;
  20         struct sg_table *sg;
  21         dma_addr_t dma_addr;
  22         int ret;
  23
  24         sg = kzalloc(sizeof(*sg), GFP_KERNEL);
  25         if (!sg)
  26                 return ERR_PTR(-ENOMEM);
  27
  28         /* camera, etc, need physically contiguous.. but we need a
  29          * better way to know this..
  30          */
  31         ret = omap_gem_pin(obj, &dma_addr);
  32         if (ret)
  33                 goto out;
  34
  35         ret = sg_alloc_table(sg, 1, GFP_KERNEL);
  36         if (ret)
  37                 goto out;
  38
  39         sg_init_table(sg->sgl, 1);
  40         sg_dma_len(sg->sgl) = obj->size;
  41         sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
  42         sg_dma_address(sg->sgl) = dma_addr;
  43
  44         /* this must be after omap_gem_pin() to ensure we have pages attached */
  45         omap_gem_dma_sync_buffer(obj, dir);
  46
  47         return sg;
  48 out:
  49         kfree(sg);
  50         return ERR_PTR(ret);
  51 }
  52
  53 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  54                 struct sg_table *sg, enum dma_data_direction dir)
  55 {
  56         struct drm_gem_object *obj = attachment->dmabuf->priv;
  57         omap_gem_unpin(obj);
  58         sg_free_table(sg);
  59         kfree(sg);
  60 }
  61
  62 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
  63                 enum dma_data_direction dir)
  64 {
  65         struct drm_gem_object *obj = buffer->priv;
  66         struct page **pages;
  67         if (omap_gem_flags(obj) & OMAP_BO_TILED) {
  68                 /* TODO we would need to pin at least part of the buffer to
  69                  * get de-tiled view.  For now just reject it.
  70                  */
  71                 return -ENOMEM;
  72         }
  73         /* make sure we have the pages: */
  74         return omap_gem_get_pages(obj, &pages, true);
  75 }
  76
  77 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
  78                                           enum dma_data_direction dir)
  79 {
  80         struct drm_gem_object *obj = buffer->priv;
  81         omap_gem_put_pages(obj);
  82         return 0;
  83 }
  84
  85 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
  86                 unsigned long page_num)
  87 {
  88         struct drm_gem_object *obj = buffer->priv;
  89         struct page **pages;
  90         omap_gem_get_pages(obj, &pages, false);
  91         omap_gem_cpu_sync_page(obj, page_num);
  92         return kmap(pages[page_num]);
  93 }
  94
  95 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
  96                 unsigned long page_num, void *addr)
  97 {
  98         struct drm_gem_object *obj = buffer->priv;
  99         struct page **pages;
 100         omap_gem_get_pages(obj, &pages, false);
 101         kunmap(pages[page_num]);
 102 }
 103
 104 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 105                 struct vm_area_struct *vma)
 106 {
 107         struct drm_gem_object *obj = buffer->priv;
 108         int ret = 0;
 109
 110         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
 111         if (ret < 0)
 112                 return ret;
 113
 114         return omap_gem_mmap_obj(obj, vma);
 115 }
 116
 117 static const struct dma_buf_ops omap_dmabuf_ops = {
 118         .map_dma_buf = omap_gem_map_dma_buf,
 119         .unmap_dma_buf = omap_gem_unmap_dma_buf,
 120         .release = drm_gem_dmabuf_release,
 121         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 122         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
 123         .map = omap_gem_dmabuf_kmap,
 124         .unmap = omap_gem_dmabuf_kunmap,
 125         .mmap = omap_gem_dmabuf_mmap,
 126 };
 127
 128 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
 129                 struct drm_gem_object *obj, int flags)
 130 {
 131         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 132
 133         exp_info.ops = &omap_dmabuf_ops;
 134         exp_info.size = obj->size;
 135         exp_info.flags = flags;
 136         exp_info.priv = obj;
 137
 138         return drm_gem_dmabuf_export(dev, &exp_info);
 139 }
 140
 141 /* -----------------------------------------------------------------------------
 142  * DMABUF Import
 143  */
 144
 145 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 146                                              struct dma_buf *dma_buf)
 147 {
 148         struct dma_buf_attachment *attach;
 149         struct drm_gem_object *obj;
 150         struct sg_table *sgt;
 151         int ret;
 152
 153         if (dma_buf->ops == &omap_dmabuf_ops) {
 154                 obj = dma_buf->priv;
 155                 if (obj->dev == dev) {
 156                         /*
 157                          * Importing dmabuf exported from out own gem increases
 158                          * refcount on gem itself instead of f_count of dmabuf.
 159                          */
 160                         drm_gem_object_get(obj);
 161                         return obj;
 162                 }
 163         }
 164
 165         attach = dma_buf_attach(dma_buf, dev->dev);
 166         if (IS_ERR(attach))
 167                 return ERR_CAST(attach);
 168
 169         get_dma_buf(dma_buf);
 170
 171         sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
 172         if (IS_ERR(sgt)) {
 173                 ret = PTR_ERR(sgt);
 174                 goto fail_detach;
 175         }
 176
 177         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 178         if (IS_ERR(obj)) {
 179                 ret = PTR_ERR(obj);
 180                 goto fail_unmap;
 181         }
 182
 183         obj->import_attach = attach;
 184
 185         return obj;
 186
 187 fail_unmap:
 188         dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
 189 fail_detach:
 190         dma_buf_detach(dma_buf, attach);
 191         dma_buf_put(dma_buf);
 192
 193         return ERR_PTR(ret);
 194 }