/*

 * Copyright (C) 2016 Etnaviv Project

 *

 * 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.

 *

 * Authors:

 *    Christian Gmeiner <christian.gmeiner@gmail.com>

 */

#include "etnaviv_priv.h"

#include "etnaviv_drmif.h"

drm_private void bo_del(struct etna_bo *bo);

drm_private extern pthread_mutex_t table_lock;

static void add_bucket(struct etna_bo_cache *cache, int size)

{

	unsigned i = cache->num_buckets;

	assert(i < ARRAY_SIZE(cache->cache_bucket));

	list_inithead(&cache->cache_bucket[i].list);

	cache->cache_bucket[i].size = size;

	cache->num_buckets++;

}

drm_private void etna_bo_cache_init(struct etna_bo_cache *cache)

{

	unsigned long size, cache_max_size = 64 * 1024 * 1024;

	/* OK, so power of two buckets was too wasteful of memory.

	 * Give 3 other sizes between each power of two, to hopefully

	 * cover things accurately enough.  (The alternative is

	 * probably to just go for exact matching of sizes, and assume

	 * that for things like composited window resize the tiled

	 * width/height alignment and rounding of sizes to pages will

	 * get us useful cache hit rates anyway)

	 */

	add_bucket(cache, 4096);

	add_bucket(cache, 4096 * 2);

	add_bucket(cache, 4096 * 3);

	/* Initialize the linked lists for BO reuse cache. */

	for (size = 4 * 4096; size <= cache_max_size; size *= 2) {

		add_bucket(cache, size);

		add_bucket(cache, size + size * 1 / 4);

		add_bucket(cache, size + size * 2 / 4);

		add_bucket(cache, size + size * 3 / 4);

	}

}

/* Frees older cached buffers.  Called under table_lock */

drm_private void etna_bo_cache_cleanup(struct etna_bo_cache *cache, time_t time)

{

	unsigned i;

	if (cache->time == time)

		return;

	for (i = 0; i < cache->num_buckets; i++) {

		struct etna_bo_bucket *bucket = &cache->cache_bucket[i];

		struct etna_bo *bo;

		while (!LIST_IS_EMPTY(&bucket->list)) {

			bo = LIST_ENTRY(struct etna_bo, bucket->list.next, list);

			/* keep things in cache for at least 1 second: */

			if (time && ((time - bo->free_time) <= 1))

				break;

			list_del(&bo->list);

			bo_del(bo);

		}

	}

	cache->time = time;

}

static struct etna_bo_bucket *get_bucket(struct etna_bo_cache *cache, uint32_t size)

{

	unsigned i;

	/* hmm, this is what intel does, but I suppose we could calculate our

	 * way to the correct bucket size rather than looping..

	 */

	for (i = 0; i < cache->num_buckets; i++) {

		struct etna_bo_bucket *bucket = &cache->cache_bucket[i];

		if (bucket->size >= size) {

			return bucket;

		}

	}

	return NULL;

}

static int is_idle(struct etna_bo *bo)

{

	return etna_bo_cpu_prep(bo,

			DRM_ETNA_PREP_READ |

			DRM_ETNA_PREP_WRITE |

			DRM_ETNA_PREP_NOSYNC) == 0;

}

static struct etna_bo *find_in_bucket(struct etna_bo_bucket *bucket, uint32_t flags)

{

	struct etna_bo *bo = NULL, *tmp;

	pthread_mutex_lock(&table_lock);

	if (LIST_IS_EMPTY(&bucket->list))

		goto out_unlock;

	LIST_FOR_EACH_ENTRY_SAFE(bo, tmp, &bucket->list, list) {

		/* skip BOs with different flags */

		if (bo->flags != flags)

			continue;

		/* check if the first BO with matching flags is idle */

		if (is_idle(bo)) {

			list_delinit(&bo->list);

			goto out_unlock;

		}

		/* If the oldest BO is still busy, don't try younger ones */

		break;

	}

	/* There was no matching buffer found */

	bo = NULL;

out_unlock:

	pthread_mutex_unlock(&table_lock);

	return bo;

}

/* allocate a new (un-tiled) buffer object

 *

 * NOTE: size is potentially rounded up to bucket size

 */

drm_private struct etna_bo *etna_bo_cache_alloc(struct etna_bo_cache *cache, uint32_t *size,

    uint32_t flags)

{

	struct etna_bo *bo;

	struct etna_bo_bucket *bucket;

	*size = ALIGN(*size, 4096);

	bucket = get_bucket(cache, *size);

	/* see if we can be green and recycle: */

	if (bucket) {

		*size = bucket->size;

		bo = find_in_bucket(bucket, flags);

		if (bo) {

			atomic_set(&bo->refcnt, 1);

			etna_device_ref(bo->dev);

			return bo;

		}

	}

	return NULL;

}

drm_private int etna_bo_cache_free(struct etna_bo_cache *cache, struct etna_bo *bo)

{

	struct etna_bo_bucket *bucket = get_bucket(cache, bo->size);

	/* see if we can be green and recycle: */

	if (bucket) {

		struct timespec time;

		clock_gettime(CLOCK_MONOTONIC, &time);

		bo->free_time = time.tv_sec;

		list_addtail(&bo->list, &bucket->list);

		etna_bo_cache_cleanup(cache, time.tv_sec);

		/* bo's in the bucket cache don't have a ref and

		 * don't hold a ref to the dev:

		 */

		etna_device_del_locked(bo->dev);

		return 0;

	}

	return -1;

}