drivers/staging/omapdrm/omap_gem_dmabuf.c

   1 /*
   2  * drivers/staging/omapdrm/omap_gem_dmabuf.c
   3  *
   4  * Copyright (C) 2011 Texas Instruments
   5  * Author: Rob Clark <rob.clark@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "omap_drv.h"
  21
  22 #include <linux/dma-buf.h>
  23
  24 static struct sg_table *omap_gem_map_dma_buf(
  25                 struct dma_buf_attachment *attachment,
  26                 enum dma_data_direction dir)
  27 {
  28         struct drm_gem_object *obj = attachment->dmabuf->priv;
  29         struct sg_table *sg;
  30         dma_addr_t paddr;
  31         int ret;
  32
  33         sg = kzalloc(sizeof(*sg), GFP_KERNEL);
  34         if (!sg)
  35                 return ERR_PTR(-ENOMEM);
  36
  37         /* camera, etc, need physically contiguous.. but we need a
  38          * better way to know this..
  39          */
  40         ret = omap_gem_get_paddr(obj, &paddr, true);
  41         if (ret)
  42                 goto out;
  43
  44         ret = sg_alloc_table(sg, 1, GFP_KERNEL);
  45         if (ret)
  46                 goto out;
  47
  48         sg_init_table(sg->sgl, 1);
  49         sg_dma_len(sg->sgl) = obj->size;
  50         sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(paddr)), obj->size, 0);
  51         sg_dma_address(sg->sgl) = paddr;
  52
  53         /* this should be after _get_paddr() to ensure we have pages attached */
  54         omap_gem_dma_sync(obj, dir);
  55
  56 out:
  57         if (ret)
  58                 return ERR_PTR(ret);
  59         return sg;
  60 }
  61
  62 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
  63                 struct sg_table *sg, enum dma_data_direction dir)
  64 {
  65         struct drm_gem_object *obj = attachment->dmabuf->priv;
  66         omap_gem_put_paddr(obj);
  67         sg_free_table(sg);
  68         kfree(sg);
  69 }
  70
  71 static void omap_gem_dmabuf_release(struct dma_buf *buffer)
  72 {
  73         struct drm_gem_object *obj = buffer->priv;
  74         /* release reference that was taken when dmabuf was exported
  75          * in omap_gem_prime_set()..
  76          */
  77         drm_gem_object_unreference_unlocked(obj);
  78 }
  79
  80
  81 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
  82                 size_t start, size_t len, enum dma_data_direction dir)
  83 {
  84         struct drm_gem_object *obj = buffer->priv;
  85         struct page **pages;
  86         if (omap_gem_flags(obj) & OMAP_BO_TILED) {
  87                 /* TODO we would need to pin at least part of the buffer to
  88                  * get de-tiled view.  For now just reject it.
  89                  */
  90                 return -ENOMEM;
  91         }
  92         /* make sure we have the pages: */
  93         return omap_gem_get_pages(obj, &pages, true);
  94 }
  95
  96 static void omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
  97                 size_t start, size_t len, enum dma_data_direction dir)
  98 {
  99         struct drm_gem_object *obj = buffer->priv;
 100         omap_gem_put_pages(obj);
 101 }
 102
 103
 104 static void *omap_gem_dmabuf_kmap_atomic(struct dma_buf *buffer,
 105                 unsigned long page_num)
 106 {
 107         struct drm_gem_object *obj = buffer->priv;
 108         struct page **pages;
 109         omap_gem_get_pages(obj, &pages, false);
 110         omap_gem_cpu_sync(obj, page_num);
 111         return kmap_atomic(pages[page_num]);
 112 }
 113
 114 static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer,
 115                 unsigned long page_num, void *addr)
 116 {
 117         kunmap_atomic(addr);
 118 }
 119
 120 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
 121                 unsigned long page_num)
 122 {
 123         struct drm_gem_object *obj = buffer->priv;
 124         struct page **pages;
 125         omap_gem_get_pages(obj, &pages, false);
 126         omap_gem_cpu_sync(obj, page_num);
 127         return kmap(pages[page_num]);
 128 }
 129
 130 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
 131                 unsigned long page_num, void *addr)
 132 {
 133         struct drm_gem_object *obj = buffer->priv;
 134         struct page **pages;
 135         omap_gem_get_pages(obj, &pages, false);
 136         kunmap(pages[page_num]);
 137 }
 138
 139 /*
 140  * TODO maybe we can split up drm_gem_mmap to avoid duplicating
 141  * some here.. or at least have a drm_dmabuf_mmap helper.
 142  */
 143 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 144                 struct vm_area_struct *vma)
 145 {
 146         struct drm_gem_object *obj = buffer->priv;
 147         int ret = 0;
 148
 149         if (WARN_ON(!obj->filp))
 150                 return -EINVAL;
 151
 152         /* Check for valid size. */
 153         if (omap_gem_mmap_size(obj) < vma->vm_end - vma->vm_start) {
 154                 ret = -EINVAL;
 155                 goto out_unlock;
 156         }
 157
 158         if (!obj->dev->driver->gem_vm_ops) {
 159                 ret = -EINVAL;
 160                 goto out_unlock;
 161         }
 162
 163         vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
 164         vma->vm_ops = obj->dev->driver->gem_vm_ops;
 165         vma->vm_private_data = obj;
 166         vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 167
 168         /* Take a ref for this mapping of the object, so that the fault
 169          * handler can dereference the mmap offset's pointer to the object.
 170          * This reference is cleaned up by the corresponding vm_close
 171          * (which should happen whether the vma was created by this call, or
 172          * by a vm_open due to mremap or partial unmap or whatever).
 173          */
 174         vma->vm_ops->open(vma);
 175
 176 out_unlock:
 177
 178         return omap_gem_mmap_obj(obj, vma);
 179 }
 180
 181 struct dma_buf_ops omap_dmabuf_ops = {
 182                 .map_dma_buf = omap_gem_map_dma_buf,
 183                 .unmap_dma_buf = omap_gem_unmap_dma_buf,
 184                 .release = omap_gem_dmabuf_release,
 185                 .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 186                 .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
 187                 .kmap_atomic = omap_gem_dmabuf_kmap_atomic,
 188                 .kunmap_atomic = omap_gem_dmabuf_kunmap_atomic,
 189                 .kmap = omap_gem_dmabuf_kmap,
 190                 .kunmap = omap_gem_dmabuf_kunmap,
 191                 .mmap = omap_gem_dmabuf_mmap,
 192 };
 193
 194 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
 195                 struct drm_gem_object *obj, int flags)
 196 {
 197         return dma_buf_export(obj, &omap_dmabuf_ops, obj->size, flags);
 198 }
 199
 200 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
 201                 struct dma_buf *buffer)
 202 {
 203         struct drm_gem_object *obj;
 204
 205         /* is this one of own objects? */
 206         if (buffer->ops == &omap_dmabuf_ops) {
 207                 obj = buffer->priv;
 208                 /* is it from our device? */
 209                 if (obj->dev == dev) {
 210                         /*
 211                          * Importing dmabuf exported from out own gem increases
 212                          * refcount on gem itself instead of f_count of dmabuf.
 213                          */
 214                         drm_gem_object_reference(obj);
 215                         dma_buf_put(buffer);
 216                         return obj;
 217                 }
 218         }
 219
 220         /*
 221          * TODO add support for importing buffers from other devices..
 222          * for now we don't need this but would be nice to add eventually
 223          */
 224         return ERR_PTR(-EINVAL);
 225 }