Re: [PATCH 4/4] drm: Renesas SH Mobile DRM driver

On Wed, May 30, 2012 at 02:32:59PM +0200, Laurent Pinchart wrote:

The SH Mobile LCD controller (LCDC) DRM driver supports the main graphics plane in RGB and YUV formats, as well as the overlay planes (in alpha-blending mode only).

Only flat panel outputs using the parallel interface are supported. Support for SYS panels, HDMI and DSI is currently not implemented.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

[...]

+int shmob_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) +{

• struct drm_file *priv = filp->private_data;
• struct drm_device *dev = priv->minor->dev;
• struct drm_gem_mm *mm = dev->mm_private;
• struct shmob_drm_gem_object *sobj;
• struct drm_local_map *map;
• struct drm_gem_object *obj;
• struct drm_hash_item *hash;
• pgprot_t prot;
• int ret;
• if (drm_device_is_unplugged(dev))

• return -ENODEV;
  

• mutex_lock(&dev->struct_mutex);
• if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {

• ret = -EINVAL;
  

• goto out_unlock;
  

• }
• map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
• if (!map ||

•    ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
  

• ret =  -EPERM;
  

• goto out_unlock;
  

• }
• /* Check for valid size. */
• if (map->size < vma->vm_end - vma->vm_start) {

• ret = -EINVAL;
  

• goto out_unlock;
  

• }
• obj = map->handle;
• if (!obj->dev->driver->gem_vm_ops) {

• ret = -EINVAL;
  

• goto out_unlock;
  

• }
• sobj = to_shmob_gem_object(obj);
• prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
• ret = remap_pfn_range(vma, vma->vm_start, sobj->dma >> PAGE_SHIFT,

• 	      vma->vm_end - vma->vm_start, prot);
  

• if (ret < 0)

• goto out_unlock;
  

• vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
• vma->vm_ops = obj->dev->driver->gem_vm_ops;
• vma->vm_private_data = obj;
• vma->vm_page_prot = prot;
• /* Take a ref for this mapping of the object, so that the fault

• * handler can dereference the mmap offset's pointer to the object.
  

• * This reference is cleaned up by the corresponding vm_close
  

• * (which should happen whether the vma was created by this call, or
  

• * by a vm_open due to mremap or partial unmap or whatever).
  

• */
  

• drm_gem_object_reference(obj);
• drm_vm_open_locked(dev, vma);

+out_unlock:

• mutex_unlock(&dev->struct_mutex);
• return ret;

+}

I just noticed this function is nearly a copy of drm_gem_mmap except for the the additional remap_pfn_range here. Would it make sense to turn drm_gem_mmap into a wrapper around a drm_gem_mmap_locked, call this one from here and add the remap_pfn_range?

If yes, I would do so in my cma gem helper patch.

Sascha