// SPDX-License-Identifier: MIT
/*
 * Copyright © 2019 Intel Corporation
 */

#include "intel_memory_region.h"
#include "i915_gem_region.h"
#include "i915_drv.h"
#include "i915_trace.h"

void
i915_gem_object_put_pages_buddy(struct drm_i915_gem_object *obj,
				struct sg_table *pages)
{
	__intel_memory_region_put_pages_buddy(obj->mm.region, &obj->mm.blocks);

	obj->mm.dirty = false;
	sg_free_table(pages);
	kfree(pages);
}

int
i915_gem_object_get_pages_buddy(struct drm_i915_gem_object *obj)
{
	const u64 max_segment = i915_sg_segment_size();
	struct intel_memory_region *mem = obj->mm.region;
	struct list_head *blocks = &obj->mm.blocks;
	resource_size_t size = obj->base.size;
	resource_size_t prev_end;
	struct i915_buddy_block *block;
	unsigned int flags;
	struct sg_table *st;
	struct scatterlist *sg;
	unsigned int sg_page_sizes;
	int ret;

	st = kmalloc(sizeof(*st), GFP_KERNEL);
	if (!st)
		return -ENOMEM;

	if (sg_alloc_table(st, size >> PAGE_SHIFT, GFP_KERNEL)) {
		kfree(st);
		return -ENOMEM;
	}

	flags = I915_ALLOC_MIN_PAGE_SIZE;
	if (obj->flags & I915_BO_ALLOC_CONTIGUOUS)
		flags |= I915_ALLOC_CONTIGUOUS;

	ret = __intel_memory_region_get_pages_buddy(mem, size, flags, blocks);
	if (ret)
		goto err_free_sg;

	GEM_BUG_ON(list_empty(blocks));

	sg = st->sgl;
	st->nents = 0;
	sg_page_sizes = 0;
	prev_end = (resource_size_t)-1;

	list_for_each_entry(block, blocks, link) {
		u64 block_size, offset;

		block_size = min_t(u64, size,
				   i915_buddy_block_size(&mem->mm, block));
		offset = i915_buddy_block_offset(block);

		while (block_size) {
			u64 len;

			if (offset != prev_end || sg->length >= max_segment) {
				if (st->nents) {
					sg_page_sizes |= sg->length;
					sg = __sg_next(sg);
				}

				sg_dma_address(sg) = mem->region.start + offset;
				sg_dma_len(sg) = 0;
				sg->length = 0;
				st->nents++;
			}

			len = min(block_size, max_segment - sg->length);
			sg->length += len;
			sg_dma_len(sg) += len;

			offset += len;
			block_size -= len;

			prev_end = offset;
		}
	}

	sg_page_sizes |= sg->length;
	sg_mark_end(sg);
	i915_sg_trim(st);

	__i915_gem_object_set_pages(obj, st, sg_page_sizes);

	return 0;

err_free_sg:
	sg_free_table(st);
	kfree(st);
	return ret;
}

void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
					struct intel_memory_region *mem,
					unsigned long flags)
{
	INIT_LIST_HEAD(&obj->mm.blocks);
	obj->mm.region = intel_memory_region_get(mem);

	obj->flags |= flags;
	if (obj->base.size <= mem->min_page_size)
		obj->flags |= I915_BO_ALLOC_CONTIGUOUS;

	mutex_lock(&mem->objects.lock);

	if (obj->flags & I915_BO_ALLOC_VOLATILE)
		list_add(&obj->mm.region_link, &mem->objects.purgeable);
	else
		list_add(&obj->mm.region_link, &mem->objects.list);

	mutex_unlock(&mem->objects.lock);
}

void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj)
{
	struct intel_memory_region *mem = obj->mm.region;

	mutex_lock(&mem->objects.lock);
	list_del(&obj->mm.region_link);
	mutex_unlock(&mem->objects.lock);

	intel_memory_region_put(mem);
}

struct drm_i915_gem_object *
i915_gem_object_create_region(struct intel_memory_region *mem,
			      resource_size_t size,
			      unsigned int flags)
{
	struct drm_i915_gem_object *obj;
	int err;

	/*
	 * NB: Our use of resource_size_t for the size stems from using struct
	 * resource for the mem->region. We might need to revisit this in the
	 * future.
	 */

	GEM_BUG_ON(flags & ~I915_BO_ALLOC_FLAGS);

	if (!mem)
		return ERR_PTR(-ENODEV);

	size = round_up(size, mem->min_page_size);

	GEM_BUG_ON(!size);
	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_MIN_ALIGNMENT));

	/*
	 * XXX: There is a prevalence of the assumption that we fit the
	 * object's page count inside a 32bit _signed_ variable. Let's document
	 * this and catch if we ever need to fix it. In the meantime, if you do
	 * spot such a local variable, please consider fixing!
	 */

	if (size >> PAGE_SHIFT > INT_MAX)
		return ERR_PTR(-E2BIG);

	if (overflows_type(size, obj->base.size))
		return ERR_PTR(-E2BIG);

	obj = i915_gem_object_alloc();
	if (!obj)
		return ERR_PTR(-ENOMEM);

	err = mem->ops->init_object(mem, obj, size, flags);
	if (err)
		goto err_object_free;

	trace_i915_gem_object_create(obj);
	return obj;

err_object_free:
	i915_gem_object_free(obj);
	return ERR_PTR(err);
}