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drm_gem_vm.c revision 1.4 
      1 /*	$NetBSD: drm_gem_vm.c,v 1.4 2014/07/16 20:56:25 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: drm_gem_vm.c,v 1.4 2014/07/16 20:56:25 riastradh Exp $");
     34 
     35 #include <sys/types.h>
     36 
     37 #include <uvm/uvm_extern.h>
     38 
     39 #include <drm/drmP.h>
     40 #include <drm/drm_vma_manager.h>
     41 
     42 static int	drm_gem_mmap_object_locked(struct drm_device *, off_t, size_t,
     43 		    int, struct uvm_object **, voff_t *);
     44 
     45 void
     46 drm_gem_pager_reference(struct uvm_object *uobj)
     47 {
     48 	struct drm_gem_object *const obj = container_of(uobj,
     49 	    struct drm_gem_object, gemo_uvmobj);
     50 
     51 	drm_gem_object_reference(obj);
     52 }
     53 
     54 void
     55 drm_gem_pager_detach(struct uvm_object *uobj)
     56 {
     57 	struct drm_gem_object *const obj = container_of(uobj,
     58 	    struct drm_gem_object, gemo_uvmobj);
     59 
     60 	drm_gem_object_unreference_unlocked(obj);
     61 }
     62 
     63 int
     64 drm_gem_mmap_object(struct drm_device *dev, off_t byte_offset, size_t nbytes,
     65     int prot, struct uvm_object **uobjp, voff_t *uoffsetp)
     66 {
     67 	int ret;
     68 
     69 	mutex_lock(&dev->struct_mutex);
     70 	ret = drm_gem_mmap_object_locked(dev, byte_offset, nbytes, prot,
     71 	    uobjp, uoffsetp);
     72 	mutex_unlock(&dev->struct_mutex);
     73 
     74 	return ret;
     75 }
     76 
     77 static int
     78 drm_gem_mmap_object_locked(struct drm_device *dev, off_t byte_offset,
     79     size_t nbytes, int prot __unused, struct uvm_object **uobjp,
     80     voff_t *uoffsetp)
     81 {
     82 	const unsigned long startpage = (byte_offset >> PAGE_SHIFT);
     83 	const unsigned long npages = (nbytes >> PAGE_SHIFT);
     84 
     85 	KASSERT(mutex_is_locked(&dev->struct_mutex));
     86 	KASSERT(drm_core_check_feature(dev, DRIVER_GEM));
     87 	KASSERT(dev->driver->gem_uvm_ops != NULL);
     88 	KASSERT(prot == (prot & (PROT_READ | PROT_WRITE)));
     89 	KASSERT(0 <= byte_offset);
     90 	KASSERT(byte_offset == (byte_offset & ~(PAGE_SIZE-1)));
     91 	KASSERT(nbytes == (npages << PAGE_SHIFT));
     92 
     93 	struct drm_vma_offset_node *const node =
     94 	    drm_vma_offset_exact_lookup(dev->vma_offset_manager, startpage,
     95 		npages);
     96 	if (node == NULL) {
     97 		/* Fall back to vanilla device mappings.  */
     98 		*uobjp = NULL;
     99 		*uoffsetp = (voff_t)-1;
    100 		return 0;
    101 	}
    102 
    103 	struct drm_gem_object *const obj = container_of(node,
    104 	    struct drm_gem_object, vma_node);
    105 	KASSERT(obj->dev == dev);
    106 
    107 	/* Success!  */
    108 	drm_gem_object_reference(obj);
    109 	*uobjp = &obj->gemo_uvmobj;
    110 	*uoffsetp = 0;
    111 	return 0;
    112 }
    113