/* -*- mode: C; c-file-style: "k&r"; tab-width 4; indent-tabs-mode: t; -*- */

/*

 * Copyright (C) 2016 Rob Clark <robclark@freedesktop.org>

 *

 * 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:

 *    Rob Clark <robclark@freedesktop.org>

 */

#include "freedreno_drmif.h"

#include "freedreno_priv.h"

drm_private void bo_del(struct fd_bo *bo);

drm_private extern pthread_mutex_t table_lock;

static void

add_bucket(struct fd_bo_cache *cache, int size)

{

	unsigned int 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++;

}

/**

 * @coarse: if true, only power-of-two bucket sizes, otherwise

 *    fill in for a bit smoother size curve..

 */

drm_private void

fd_bo_cache_init(struct fd_bo_cache *cache, int coarse)

{

	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);

	if (!coarse)

		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);

		if (!coarse) {

			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

fd_bo_cache_cleanup(struct fd_bo_cache *cache, time_t time)

{

	int i;

	if (cache->time == time)

		return;

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

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

		struct fd_bo *bo;

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

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

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

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

				break;

			VG_BO_OBTAIN(bo);

			list_del(&bo->list);

			bo_del(bo);

		}

	}

	cache->time = time;

}

static struct fd_bo_bucket * get_bucket(struct fd_bo_cache *cache, uint32_t size)

{

	int 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 fd_bo_bucket *bucket = &cache->cache_bucket[i];

		if (bucket->size >= size) {

			return bucket;

		}

	}

	return NULL;

}

static int is_idle(struct fd_bo *bo)

{

	return fd_bo_cpu_prep(bo, NULL,

			DRM_FREEDRENO_PREP_READ |

			DRM_FREEDRENO_PREP_WRITE |

			DRM_FREEDRENO_PREP_NOSYNC) == 0;

}

static struct fd_bo *find_in_bucket(struct fd_bo_bucket *bucket, uint32_t flags)

{

	struct fd_bo *bo = NULL;

	/* TODO .. if we had an ALLOC_FOR_RENDER flag like intel, we could

	 * skip the busy check.. if it is only going to be a render target

	 * then we probably don't need to stall..

	 *

	 * NOTE that intel takes ALLOC_FOR_RENDER bo's from the list tail

	 * (MRU, since likely to be in GPU cache), rather than head (LRU)..

	 */

	pthread_mutex_lock(&table_lock);

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

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

		/* TODO check for compatible flags? */

		if (is_idle(bo)) {

			list_del(&bo->list);

		} else {

			bo = NULL;

		}

	}

	pthread_mutex_unlock(&table_lock);

	return bo;

}

/* NOTE: size is potentially rounded up to bucket size: */

drm_private struct fd_bo *

fd_bo_cache_alloc(struct fd_bo_cache *cache, uint32_t *size, uint32_t flags)

{

	struct fd_bo *bo = NULL;

	struct fd_bo_bucket *bucket;

	*size = ALIGN(*size, 4096);

	bucket = get_bucket(cache, *size);

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

retry:

	if (bucket) {

		*size = bucket->size;

		bo = find_in_bucket(bucket, flags);

		if (bo) {

			VG_BO_OBTAIN(bo);

			if (bo->funcs->madvise(bo, TRUE) <= 0) {

				/* we've lost the backing pages, delete and try again: */

				pthread_mutex_lock(&table_lock);

				bo_del(bo);

				pthread_mutex_unlock(&table_lock);

				goto retry;

			}

			atomic_set(&bo->refcnt, 1);

			fd_device_ref(bo->dev);

			return bo;

		}

	}

	return NULL;

}

drm_private int

fd_bo_cache_free(struct fd_bo_cache *cache, struct fd_bo *bo)

{

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

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

	if (bucket) {

		struct timespec time;

		bo->funcs->madvise(bo, FALSE);

		clock_gettime(CLOCK_MONOTONIC, &time);

		bo->free_time = time.tv_sec;

		VG_BO_RELEASE(bo);

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

		fd_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:

		 */

		fd_device_del_locked(bo->dev);

		return 0;

	}

	return -1;

}