text: /*
   * Copyright 2014 Advanced Micro Devices, Inc.
   * All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sub license, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
   * USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   * The above copyright notice and this permission notice (including the
   * next paragraph) shall be included in all copies or substantial portions
   * of the Software.
   *
   */
  /*
   * Authors:
   *    Christian König <christian.koenig@amd.com>
   */
  
  #include <linux/firmware.h>
  #include <linux/module.h>
  #include <linux/mmu_notifier.h>
  #include <drm/drmP.h>
  #include <drm/drm.h>
  
  #include "radeon.h"
  
  struct radeon_mn {
  	/* constant after initialisation */
  	struct radeon_device	*rdev;
  	struct mm_struct	*mm;
  	struct mmu_notifier	mn;
  
  	/* only used on destruction */
  	struct work_struct	work;
  
  	/* protected by rdev->mn_lock */
  	struct hlist_node	node;
  
  	/* objects protected by lock */
  	struct mutex		lock;
  	struct rb_root		objects;
  };
  
  struct radeon_mn_node {
  	struct interval_tree_node	it;
  	struct list_head		bos;
  };
  
  /**
   * radeon_mn_destroy - destroy the rmn
   *
   * @work: previously sheduled work item
   *
   * Lazy destroys the notifier from a work item
   */
  static void radeon_mn_destroy(struct work_struct *work)
  {
  	struct radeon_mn *rmn = container_of(work, struct radeon_mn, work);
  	struct radeon_device *rdev = rmn->rdev;
  	struct radeon_mn_node *node, *next_node;
  	struct radeon_bo *bo, *next_bo;
  
  	mutex_lock(&rdev->mn_lock);
  	mutex_lock(&rmn->lock);
  	hash_del(&rmn->node);
  	rbtree_postorder_for_each_entry_safe(node, next_node, &rmn->objects,
  					     it.rb) {
  
  		interval_tree_remove(&node->it, &rmn->objects);
  		list_for_each_entry_safe(bo, next_bo, &node->bos, mn_list) {
  			bo->mn = NULL;
  			list_del_init(&bo->mn_list);
  		}
  		kfree(node);
  	}
  	mutex_unlock(&rmn->lock);
  	mutex_unlock(&rdev->mn_lock);
  	mmu_notifier_unregister(&rmn->mn, rmn->mm);
  	kfree(rmn);
  }
  
  /**
   * radeon_mn_release - callback to notify about mm destruction
   *
   * @mn: our notifier
   * @mn: the mm this callback is about
   *
   * Shedule a work item to lazy destroy our notifier.
   */
  static void radeon_mn_release(struct mmu_notifier *mn,
  			      struct mm_struct *mm)
  {
  	struct radeon_mn *rmn = container_of(mn, struct radeon_mn, mn);
  	INIT_WORK(&rmn->work, radeon_mn_destroy);
  	schedule_work(&rmn->work);
  }
  
  /**
   * radeon_mn_invalidate_range_start - callback to notify about mm change
   *
   * @mn: our notifier
   * @mn: the mm this callback is about
   * @start: start of updated range
   * @end: end of updated range
   *
   * We block for all BOs between start and end to be idle and
   * unmap them by move them into system domain again.
   */
  static void radeon_mn_invalidate_range_start(struct mmu_notifier *mn,
  					     struct mm_struct *mm,
  					     unsigned long start,
  					     unsigned long end)
  {
  	struct radeon_mn *rmn = container_of(mn, struct radeon_mn, mn);
  	struct interval_tree_node *it;
  
  	/* notification is exclusive, but interval is inclusive */
  	end -= 1;
  
  	mutex_lock(&rmn->lock);
  
  	it = interval_tree_iter_first(&rmn->objects, start, end);
  	while (it) {
  		struct radeon_mn_node *node;
  		struct radeon_bo *bo;
  		long r;
  
  		node = container_of(it, struct radeon_mn_node, it);
  		it = interval_tree_iter_next(it, start, end);
  
  		list_for_each_entry(bo, &node->bos, mn_list) {
  
  			if (!bo->tbo.ttm || bo->tbo.ttm->state != tt_bound)
  				continue;
  
  			r = radeon_bo_reserve(bo, true);
  			if (r) {
  				DRM_ERROR("(%ld) failed to reserve user bo\n", r);
  				continue;
  			}
  
  			r = reservation_object_wait_timeout_rcu(bo->tbo.resv,
  				true, false, MAX_SCHEDULE_TIMEOUT);
  			if (r <= 0)
  				DRM_ERROR("(%ld) failed to wait for user bo\n", r);
  
  			radeon_ttm_placement_from_domain(bo, RADEON_GEM_DOMAIN_CPU);
  			r = ttm_bo_validate(&bo->tbo, &bo->placement, false, false);
  			if (r)
  				DRM_ERROR("(%ld) failed to validate user bo\n", r);
  
  			radeon_bo_unreserve(bo);
  		}
  	}
  	
  	mutex_unlock(&rmn->lock);
  }
  
  static const struct mmu_notifier_ops radeon_mn_ops = {
  	.release = radeon_mn_release,
  	.invalidate_range_start = radeon_mn_invalidate_range_start,
  };
  
  /**
   * radeon_mn_get - create notifier context
   *
   * @rdev: radeon device pointer
   *
   * Creates a notifier context for current->mm.
   */
  static struct radeon_mn *radeon_mn_get(struct radeon_device *rdev)
  {
  	struct mm_struct *mm = current->mm;
  	struct radeon_mn *rmn;
  	int r;
  
  	if (down_write_killable(&mm->mmap_sem))
  		return ERR_PTR(-EINTR);
  
  	mutex_lock(&rdev->mn_lock);
  
  	hash_for_each_possible(rdev->mn_hash, rmn, node, (unsigned long)mm)
  		if (rmn->mm == mm)
  			goto release_locks;
  
  	rmn = kzalloc(sizeof(*rmn), GFP_KERNEL);
  	if (!rmn) {
  		rmn = ERR_PTR(-ENOMEM);
  		goto release_locks;
  	}
  
  	rmn->rdev = rdev;
  	rmn->mm = mm;
  	rmn->mn.ops = &radeon_mn_ops;
  	mutex_init(&rmn->lock);
  	rmn->objects = LINUX_RB_ROOT;
  	
  	r = __mmu_notifier_register(&rmn->mn, mm);
  	if (r)
  		goto free_rmn;
  
  	hash_add(rdev->mn_hash, &rmn->node, (unsigned long)mm);
  
  release_locks:
  	mutex_unlock(&rdev->mn_lock);
  	up_write(&mm->mmap_sem);
  
  	return rmn;
  
  free_rmn:
  	mutex_unlock(&rdev->mn_lock);
  	up_write(&mm->mmap_sem);
  	kfree(rmn);
  
  	return ERR_PTR(r);
  }
  
  /**
   * radeon_mn_register - register a BO for notifier updates
   *
   * @bo: radeon buffer object
   * @addr: userptr addr we should monitor
   *
   * Registers an MMU notifier for the given BO at the specified address.
   * Returns 0 on success, -ERRNO if anything goes wrong.
   */
  int radeon_mn_register(struct radeon_bo *bo, unsigned long addr)
  {
  	unsigned long end = addr + radeon_bo_size(bo) - 1;
  	struct radeon_device *rdev = bo->rdev;
  	struct radeon_mn *rmn;
  	struct radeon_mn_node *node = NULL;
  	struct list_head bos;
  	struct interval_tree_node *it;
  
  	rmn = radeon_mn_get(rdev);
  	if (IS_ERR(rmn))
  		return PTR_ERR(rmn);
  
  	INIT_LIST_HEAD(&bos);
  
  	mutex_lock(&rmn->lock);
  
  	while ((it = interval_tree_iter_first(&rmn->objects, addr, end))) {
  		kfree(node);
  		node = container_of(it, struct radeon_mn_node, it);
  		interval_tree_remove(&node->it, &rmn->objects);
  		addr = min(it->start, addr);
  		end = max(it->last, end);
  		list_splice(&node->bos, &bos);
  	}
  
  	if (!node) {
  		node = kmalloc(sizeof(struct radeon_mn_node), M_DRM,
  			       GFP_KERNEL);
  		if (!node) {
  			mutex_unlock(&rmn->lock);
  			return -ENOMEM;
  		}
  	}
  
  	bo->mn = rmn;
  
  	node->it.start = addr;
  	node->it.last = end;
  	INIT_LIST_HEAD(&node->bos);
  	list_splice(&bos, &node->bos);
  	list_add(&bo->mn_list, &node->bos);
  
  	interval_tree_insert(&node->it, &rmn->objects);
  
  	mutex_unlock(&rmn->lock);
  
  	return 0;
  }
  
  /**
   * radeon_mn_unregister - unregister a BO for notifier updates
   *
   * @bo: radeon buffer object
   *
   * Remove any registration of MMU notifier updates from the buffer object.
   */
  void radeon_mn_unregister(struct radeon_bo *bo)
  {
  	struct radeon_device *rdev = bo->rdev;
  	struct radeon_mn *rmn;
  	struct list_head *head;
  
  	mutex_lock(&rdev->mn_lock);
  	rmn = bo->mn;
  	if (rmn == NULL) {
  		mutex_unlock(&rdev->mn_lock);
  		return;
  	}
  
  	mutex_lock(&rmn->lock);
  	/* save the next list entry for later */
  	head = bo->mn_list.next;
  
  	bo->mn = NULL;
  	list_del(&bo->mn_list);
  
  	if (list_empty(head)) {
  		struct radeon_mn_node *node;
  		node = container_of(head, struct radeon_mn_node, bos);
  		interval_tree_remove(&node->it, &rmn->objects);
  		kfree(node);
  	}
  
  	mutex_unlock(&rmn->lock);
  	mutex_unlock(&rdev->mn_lock);
  }
  