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) {
  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 void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
  89                 unsigned long page_num)
  90 {
  91         struct drm_gem_object *obj = buffer->priv;
  92         struct page **pages;
  93         omap_gem_get_pages(obj, &pages, false);
  94         omap_gem_cpu_sync_page(obj, page_num);
  95         return kmap(pages[page_num]);
  96 }
  97
  98 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
  99                 unsigned long page_num, void *addr)
 100 {
 101         struct drm_gem_object *obj = buffer->priv;
 102         struct page **pages;
 103         omap_gem_get_pages(obj, &pages, false);
 104         kunmap(pages[page_num]);
 105 }
 106
 107 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 108                 struct vm_area_struct *vma)
 109 {
 110         struct drm_gem_object *obj = buffer->priv;
 111         int ret = 0;
 112
 113         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
 114         if (ret < 0)
 115                 return ret;
 116
 117         return omap_gem_mmap_obj(obj, vma);
 118 }
 119
 120 static const struct dma_buf_ops omap_dmabuf_ops = {
 121         .map_dma_buf = omap_gem_map_dma_buf,
 122         .unmap_dma_buf = omap_gem_unmap_dma_buf,
 123         .release = drm_gem_dmabuf_release,
 124         .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 125         .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
 126         .map = omap_gem_dmabuf_kmap,
 127         .unmap = omap_gem_dmabuf_kunmap,
 128         .mmap = omap_gem_dmabuf_mmap,
 129 };
 130
 131 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
 132 {
 133         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 134
 135         exp_info.ops = &omap_dmabuf_ops;
 136         exp_info.size = obj->size;
 137         exp_info.flags = flags;
 138         exp_info.priv = obj;
 139
 140         return drm_gem_dmabuf_export(obj->dev, &exp_info);
 141 }
 142
 143 /* -----------------------------------------------------------------------------
 144  * DMABUF Import
 145  */
 146
 147 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 148                                              struct dma_buf *dma_buf)
 149 {
 150         struct dma_buf_attachment *attach;
 151         struct drm_gem_object *obj;
 152         struct sg_table *sgt;
 153         int ret;
 154
 155         if (dma_buf->ops == &omap_dmabuf_ops) {
 156                 obj = dma_buf->priv;
 157                 if (obj->dev == dev) {
 158                         /*
 159                          * Importing dmabuf exported from out own gem increases
 160                          * refcount on gem itself instead of f_count of dmabuf.
 161                          */
 162                         drm_gem_object_get(obj);
 163                         return obj;
 164                 }
 165         }
 166
 167         attach = dma_buf_attach(dma_buf, dev->dev);
 168         if (IS_ERR(attach))
 169                 return ERR_CAST(attach);
 170
 171         get_dma_buf(dma_buf);
 172
 173         sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
 174         if (IS_ERR(sgt)) {
 175                 ret = PTR_ERR(sgt);
 176                 goto fail_detach;
 177         }
 178
 179         obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
 180         if (IS_ERR(obj)) {
 181                 ret = PTR_ERR(obj);
 182                 goto fail_unmap;
 183         }
 184
 185         obj->import_attach = attach;
 186
 187         return obj;
 188
 189 fail_unmap:
 190         dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
 191 fail_detach:
 192         dma_buf_detach(dma_buf, attach);
 193         dma_buf_put(dma_buf);
 194
 195         return ERR_PTR(ret);
 196 }