/*
 * Copyright © 2016 Intel Corporation
 *
 * 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, sublicense,
 * 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 above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS 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.
 *
 */
 
#include "i915_vma.h"

#include "i915_drv.h"
#include "intel_ringbuffer.h"
#include "intel_frontbuffer.h"

#include <drm/drm_gem.h>

static void
i915_vma_retire(struct i915_gem_active *active,
		struct drm_i915_gem_request *rq)
{
	const unsigned int idx = rq->engine->id;
	struct i915_vma *vma =
		container_of(active, struct i915_vma, last_read[idx]);
	struct drm_i915_gem_object *obj = vma->obj;

	GEM_BUG_ON(!i915_vma_has_active_engine(vma, idx));

	i915_vma_clear_active(vma, idx);
	if (i915_vma_is_active(vma))
		return;

	list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
	if (unlikely(i915_vma_is_closed(vma) && !i915_vma_is_pinned(vma)))
		WARN_ON(i915_vma_unbind(vma));

	GEM_BUG_ON(!i915_gem_object_is_active(obj));
	if (--obj->active_count)
		return;

	/* Bump our place on the bound list to keep it roughly in LRU order
	 * so that we don't steal from recently used but inactive objects
	 * (unless we are forced to ofc!)
	 */
	if (obj->bind_count)
		list_move_tail(&obj->global_link, &rq->i915->mm.bound_list);

	obj->mm.dirty = true; /* be paranoid  */

	if (i915_gem_object_has_active_reference(obj)) {
		i915_gem_object_clear_active_reference(obj);
		i915_gem_object_put(obj);
	}
}

static struct i915_vma *
__i915_vma_create(struct drm_i915_gem_object *obj,
		  struct i915_address_space *vm,
		  const struct i915_ggtt_view *view)
{
	struct i915_vma *vma;
	struct rb_node *rb, **p;
	int i;

	GEM_BUG_ON(vm->closed);

	vma = kmem_cache_zalloc(to_i915(obj->base.dev)->vmas, GFP_KERNEL);
	if (vma == NULL)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&vma->exec_list);
	for (i = 0; i < ARRAY_SIZE(vma->last_read); i++)
		init_request_active(&vma->last_read[i], i915_vma_retire);
	init_request_active(&vma->last_fence, NULL);
	list_add(&vma->vm_link, &vm->unbound_list);
	vma->vm = vm;
	vma->obj = obj;
	vma->size = obj->base.size;

	if (view) {
		vma->ggtt_view = *view;
		if (view->type == I915_GGTT_VIEW_PARTIAL) {
			vma->size = view->params.partial.size;
			vma->size <<= PAGE_SHIFT;
		} else if (view->type == I915_GGTT_VIEW_ROTATED) {
			vma->size =
				intel_rotation_info_size(&view->params.rotated);
			vma->size <<= PAGE_SHIFT;
		}
	}

	if (i915_is_ggtt(vm)) {
		vma->flags |= I915_VMA_GGTT;
		list_add(&vma->obj_link, &obj->vma_list);
	} else {
		i915_ppgtt_get(i915_vm_to_ppgtt(vm));
		list_add_tail(&vma->obj_link, &obj->vma_list);
	}

	rb = NULL;
	p = &obj->vma_tree.rb_node;
	while (*p) {
		struct i915_vma *pos;

		rb = *p;
		pos = rb_entry(rb, struct i915_vma, obj_node);
		if (i915_vma_compare(pos, vm, view) < 0)
			p = &rb->rb_right;
		else
			p = &rb->rb_left;
	}
	rb_link_node(&vma->obj_node, rb, p);
	rb_insert_color(&vma->obj_node, &obj->vma_tree);

	return vma;
}

struct i915_vma *
i915_vma_create(struct drm_i915_gem_object *obj,
		struct i915_address_space *vm,
		const struct i915_ggtt_view *view)
{
	lockdep_assert_held(&obj->base.dev->struct_mutex);
	GEM_BUG_ON(view && !i915_is_ggtt(vm));
	GEM_BUG_ON(i915_gem_obj_to_vma(obj, vm, view));

	return __i915_vma_create(obj, vm, view);
}

/**
 * i915_vma_bind - Sets up PTEs for an VMA in it's corresponding address space.
 * @vma: VMA to map
 * @cache_level: mapping cache level
 * @flags: flags like global or local mapping
 *
 * DMA addresses are taken from the scatter-gather table of this object (or of
 * this VMA in case of non-default GGTT views) and PTE entries set up.
 * Note that DMA addresses are also the only part of the SG table we care about.
 */
int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
		  u32 flags)
{
	u32 bind_flags;
	u32 vma_flags;
	int ret;

	if (WARN_ON(flags == 0))
		return -EINVAL;

	bind_flags = 0;
	if (flags & PIN_GLOBAL)
		bind_flags |= I915_VMA_GLOBAL_BIND;
	if (flags & PIN_USER)
		bind_flags |= I915_VMA_LOCAL_BIND;

	vma_flags = vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);
	if (flags & PIN_UPDATE)
		bind_flags |= vma_flags;
	else
		bind_flags &= ~vma_flags;
	if (bind_flags == 0)
		return 0;

	if (vma_flags == 0 && vma->vm->allocate_va_range) {
		trace_i915_va_alloc(vma);
		ret = vma->vm->allocate_va_range(vma->vm,
						 vma->node.start,
						 vma->node.size);
		if (ret)
			return ret;
	}

	ret = vma->vm->bind_vma(vma, cache_level, bind_flags);
	if (ret)
		return ret;

	vma->flags |= bind_flags;
	return 0;
}

void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
{
	void __iomem *ptr;

	/* Access through the GTT requires the device to be awake. */
	assert_rpm_wakelock_held(to_i915(vma->vm->dev));

	lockdep_assert_held(&vma->vm->dev->struct_mutex);
	if (WARN_ON(!i915_vma_is_map_and_fenceable(vma)))
		return IO_ERR_PTR(-ENODEV);

	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
	GEM_BUG_ON((vma->flags & I915_VMA_GLOBAL_BIND) == 0);

	ptr = vma->iomap;
	if (ptr == NULL) {
		ptr = io_mapping_map_wc(&i915_vm_to_ggtt(vma->vm)->mappable,
					vma->node.start,
					vma->node.size);
		if (ptr == NULL)
			return IO_ERR_PTR(-ENOMEM);

		vma->iomap = ptr;
	}

	__i915_vma_pin(vma);
	return ptr;
}

void i915_vma_unpin_and_release(struct i915_vma **p_vma)
{
	struct i915_vma *vma;
	struct drm_i915_gem_object *obj;

	vma = fetch_and_zero(p_vma);
	if (!vma)
		return;

	obj = vma->obj;

	i915_vma_unpin(vma);
	i915_vma_close(vma);

	__i915_gem_object_release_unless_active(obj);
}

bool
i915_vma_misplaced(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
{
	if (!drm_mm_node_allocated(&vma->node))
		return false;

	if (vma->node.size < size)
		return true;

	if (alignment && vma->node.start & (alignment - 1))
		return true;

	if (flags & PIN_MAPPABLE && !i915_vma_is_map_and_fenceable(vma))
		return true;

	if (flags & PIN_OFFSET_BIAS &&
	    vma->node.start < (flags & PIN_OFFSET_MASK))
		return true;

	if (flags & PIN_OFFSET_FIXED &&
	    vma->node.start != (flags & PIN_OFFSET_MASK))
		return true;

	return false;
}

void __i915_vma_set_map_and_fenceable(struct i915_vma *vma)
{
	struct drm_i915_gem_object *obj = vma->obj;
	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
	bool mappable, fenceable;
	u32 fence_size, fence_alignment;

	fence_size = i915_gem_get_ggtt_size(dev_priv,
					    vma->size,
					    i915_gem_object_get_tiling(obj));
	fence_alignment = i915_gem_get_ggtt_alignment(dev_priv,
						      vma->size,
						      i915_gem_object_get_tiling(obj),
						      true);

	fenceable = (vma->node.size == fence_size &&
		     (vma->node.start & (fence_alignment - 1)) == 0);

	mappable = (vma->node.start + fence_size <=
		    dev_priv->ggtt.mappable_end);

	/*
	 * Explicitly disable for rotated VMA since the display does not
	 * need the fence and the VMA is not accessible to other users.
	 */
	if (mappable && fenceable &&
	    vma->ggtt_view.type != I915_GGTT_VIEW_ROTATED)
		vma->flags |= I915_VMA_CAN_FENCE;
	else
		vma->flags &= ~I915_VMA_CAN_FENCE;
}

bool i915_gem_valid_gtt_space(struct i915_vma *vma,
			      unsigned long cache_level)
{
	struct drm_mm_node *gtt_space = &vma->node;
	struct drm_mm_node *other;

	/*
	 * On some machines we have to be careful when putting differing types
	 * of snoopable memory together to avoid the prefetcher crossing memory
	 * domains and dying. During vm initialisation, we decide whether or not
	 * these constraints apply and set the drm_mm.color_adjust
	 * appropriately.
	 */
	if (vma->vm->mm.color_adjust == NULL)
		return true;

	if (!drm_mm_node_allocated(gtt_space))
		return true;

	if (list_empty(&gtt_space->node_list))
		return true;

	other = list_entry(gtt_space->node_list.prev, struct drm_mm_node, node_list);
	if (other->allocated && !other->hole_follows && other->color != cache_level)
		return false;

	other = list_entry(gtt_space->node_list.next, struct drm_mm_node, node_list);
	if (other->allocated && !gtt_space->hole_follows && other->color != cache_level)
		return false;

	return true;
}

/**
 * i915_vma_insert - finds a slot for the vma in its address space
 * @vma: the vma
 * @size: requested size in bytes (can be larger than the VMA)
 * @alignment: required alignment
 * @flags: mask of PIN_* flags to use
 *
 * First we try to allocate some free space that meets the requirements for
 * the VMA. Failiing that, if the flags permit, it will evict an old VMA,
 * preferrably the oldest idle entry to make room for the new VMA.
 *
 * Returns:
 * 0 on success, negative error code otherwise.
 */
static int
i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
{
	struct drm_i915_private *dev_priv = to_i915(vma->vm->dev);
	struct drm_i915_gem_object *obj = vma->obj;
	u64 start, end;
	int ret;

	GEM_BUG_ON(vma->flags & (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND));
	GEM_BUG_ON(drm_mm_node_allocated(&vma->node));

	size = max(size, vma->size);
	if (flags & PIN_MAPPABLE)
		size = i915_gem_get_ggtt_size(dev_priv, size,
					      i915_gem_object_get_tiling(obj));

	alignment = max(max(alignment, vma->display_alignment),
			i915_gem_get_ggtt_alignment(dev_priv, size,
						    i915_gem_object_get_tiling(obj),
						    flags & PIN_MAPPABLE));

	start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0;

	end = vma->vm->total;
	if (flags & PIN_MAPPABLE)
		end = min_t(u64, end, dev_priv->ggtt.mappable_end);
	if (flags & PIN_ZONE_4G)
		end = min_t(u64, end, (1ULL << 32) - PAGE_SIZE);

	/* If binding the object/GGTT view requires more space than the entire
	 * aperture has, reject it early before evicting everything in a vain
	 * attempt to find space.
	 */
	if (size > end) {
		DRM_DEBUG("Attempting to bind an object larger than the aperture: request=%llu [object=%zd] > %s aperture=%llu\n",
			  size, obj->base.size,
			  flags & PIN_MAPPABLE ? "mappable" : "total",
			  end);
		return -E2BIG;
	}

	ret = i915_gem_object_pin_pages(obj);
	if (ret)
		return ret;

	if (flags & PIN_OFFSET_FIXED) {
		u64 offset = flags & PIN_OFFSET_MASK;
		if (offset & (alignment - 1) || offset > end - size) {
			ret = -EINVAL;
			goto err_unpin;
		}

		vma->node.start = offset;
		vma->node.size = size;
		vma->node.color = obj->cache_level;
		ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
		if (ret) {
			ret = i915_gem_evict_for_vma(vma);
			if (ret == 0)
				ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
			if (ret)
				goto err_unpin;
		}
	} else {
		u32 search_flag, alloc_flag;

		if (flags & PIN_HIGH) {
			search_flag = DRM_MM_SEARCH_BELOW;
			alloc_flag = DRM_MM_CREATE_TOP;
		} else {
			search_flag = DRM_MM_SEARCH_DEFAULT;
			alloc_flag = DRM_MM_CREATE_DEFAULT;
		}

		/* We only allocate in PAGE_SIZE/GTT_PAGE_SIZE (4096) chunks,
		 * so we know that we always have a minimum alignment of 4096.
		 * The drm_mm range manager is optimised to return results
		 * with zero alignment, so where possible use the optimal
		 * path.
		 */
		if (alignment <= 4096)
			alignment = 0;

search_free:
		ret = drm_mm_insert_node_in_range_generic(&vma->vm->mm,
							  &vma->node,
							  size, alignment,
							  obj->cache_level,
							  start, end,
							  search_flag,
							  alloc_flag);
		if (ret) {
			ret = i915_gem_evict_something(vma->vm, size, alignment,
						       obj->cache_level,
						       start, end,
						       flags);
			if (ret == 0)
				goto search_free;

			goto err_unpin;
		}

		GEM_BUG_ON(vma->node.start < start);
		GEM_BUG_ON(vma->node.start + vma->node.size > end);
	}
	GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, obj->cache_level));

	list_move_tail(&obj->global_link, &dev_priv->mm.bound_list);
	list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
	obj->bind_count++;
	GEM_BUG_ON(atomic_read(&obj->mm.pages_pin_count) < obj->bind_count);

	return 0;

err_unpin:
	i915_gem_object_unpin_pages(obj);
	return ret;
}

int __i915_vma_do_pin(struct i915_vma *vma,
		      u64 size, u64 alignment, u64 flags)
{
	unsigned int bound = vma->flags;
	int ret;

	lockdep_assert_held(&vma->vm->dev->struct_mutex);
	GEM_BUG_ON((flags & (PIN_GLOBAL | PIN_USER)) == 0);
	GEM_BUG_ON((flags & PIN_GLOBAL) && !i915_vma_is_ggtt(vma));

	if (WARN_ON(bound & I915_VMA_PIN_OVERFLOW)) {
		ret = -EBUSY;
		goto err;
	}

	if ((bound & I915_VMA_BIND_MASK) == 0) {
		ret = i915_vma_insert(vma, size, alignment, flags);
		if (ret)
			goto err;
	}

	ret = i915_vma_bind(vma, vma->obj->cache_level, flags);
	if (ret)
		goto err;

	if ((bound ^ vma->flags) & I915_VMA_GLOBAL_BIND)
		__i915_vma_set_map_and_fenceable(vma);

	GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
	return 0;

err:
	__i915_vma_unpin(vma);
	return ret;
}

void i915_vma_destroy(struct i915_vma *vma)
{
	GEM_BUG_ON(vma->node.allocated);
	GEM_BUG_ON(i915_vma_is_active(vma));
	GEM_BUG_ON(!i915_vma_is_closed(vma));
	GEM_BUG_ON(vma->fence);

	list_del(&vma->vm_link);
	if (!i915_vma_is_ggtt(vma))
		i915_ppgtt_put(i915_vm_to_ppgtt(vma->vm));

	kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
}

void i915_vma_close(struct i915_vma *vma)
{
	GEM_BUG_ON(i915_vma_is_closed(vma));
	vma->flags |= I915_VMA_CLOSED;

	list_del(&vma->obj_link);
	rb_erase(&vma->obj_node, &vma->obj->vma_tree);

	if (!i915_vma_is_active(vma) && !i915_vma_is_pinned(vma))
		WARN_ON(i915_vma_unbind(vma));
}

static void __i915_vma_iounmap(struct i915_vma *vma)
{
	GEM_BUG_ON(i915_vma_is_pinned(vma));

	if (vma->iomap == NULL)
		return;

	io_mapping_unmap(vma->iomap);
	vma->iomap = NULL;
}

int i915_vma_unbind(struct i915_vma *vma)
{
	struct drm_i915_gem_object *obj = vma->obj;
	unsigned long active;
	int ret;

	lockdep_assert_held(&obj->base.dev->struct_mutex);

	/* First wait upon any activity as retiring the request may
	 * have side-effects such as unpinning or even unbinding this vma.
	 */
	active = i915_vma_get_active(vma);
	if (active) {
		int idx;

		/* When a closed VMA is retired, it is unbound - eek.
		 * In order to prevent it from being recursively closed,
		 * take a pin on the vma so that the second unbind is
		 * aborted.
		 *
		 * Even more scary is that the retire callback may free
		 * the object (last active vma). To prevent the explosion
		 * we defer the actual object free to a worker that can
		 * only proceed once it acquires the struct_mutex (which
		 * we currently hold, therefore it cannot free this object
		 * before we are finished).
		 */
		__i915_vma_pin(vma);

		for_each_active(active, idx) {
			ret = i915_gem_active_retire(&vma->last_read[idx],
						   &vma->vm->dev->struct_mutex);
			if (ret)
				break;
		}

		__i915_vma_unpin(vma);
		if (ret)
			return ret;

		GEM_BUG_ON(i915_vma_is_active(vma));
	}

	if (i915_vma_is_pinned(vma))
		return -EBUSY;

	if (!drm_mm_node_allocated(&vma->node))
		goto destroy;

	GEM_BUG_ON(obj->bind_count == 0);
	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));

	if (i915_vma_is_map_and_fenceable(vma)) {
		/* release the fence reg _after_ flushing */
		ret = i915_vma_put_fence(vma);
		if (ret)
			return ret;

		/* Force a pagefault for domain tracking on next user access */
		i915_gem_release_mmap(obj);

		__i915_vma_iounmap(vma);
		vma->flags &= ~I915_VMA_CAN_FENCE;
	}

	if (likely(!vma->vm->closed)) {
		trace_i915_vma_unbind(vma);
		vma->vm->unbind_vma(vma);
	}
	vma->flags &= ~(I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND);

	drm_mm_remove_node(&vma->node);
	list_move_tail(&vma->vm_link, &vma->vm->unbound_list);

	if (vma->pages != obj->mm.pages) {
		GEM_BUG_ON(!vma->pages);
		sg_free_table(vma->pages);
		kfree(vma->pages);
	}
	vma->pages = NULL;

	/* Since the unbound list is global, only move to that list if
	 * no more VMAs exist. */
	if (--obj->bind_count == 0)
		list_move_tail(&obj->global_link,
			       &to_i915(obj->base.dev)->mm.unbound_list);

	/* And finally now the object is completely decoupled from this vma,
	 * we can drop its hold on the backing storage and allow it to be
	 * reaped by the shrinker.
	 */
	i915_gem_object_unpin_pages(obj);

destroy:
	if (unlikely(i915_vma_is_closed(vma)))
		i915_vma_destroy(vma);

	return 0;
}