/*
 * Copyright (c) 2016  Intel Corporation.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <rte_malloc.h>
#include <rte_errno.h>

#include "tcp_stream.h"
#include "tcp_rxq.h"

#define	OFO_FRACTION	4

#define OFO_DB_MAX	0x20U

#define OFODB_OBJ_MIN	8U
#define OFODB_OBJ_MAX	0x20U

#define OFO_OBJ_MAX	(OFODB_OBJ_MAX * OFO_DB_MAX)

void
tcp_ofo_free(struct ofo *ofo)
{
	rte_free(ofo);
}

static void
calc_ofo_elems(uint32_t nbufs, uint32_t *nobj, uint32_t *ndb)
{
	uint32_t n, nd, no;

	n = nbufs / OFO_FRACTION;
	n = RTE_MAX(n, OFODB_OBJ_MIN);
	n = RTE_MIN(n, OFO_OBJ_MAX);

	no = OFODB_OBJ_MIN / 2;
	do {
		no *= 2;
		nd = n / no;
	} while (nd > OFO_DB_MAX);

	*nobj = no;
	*ndb = nd;
}

struct ofo *
tcp_ofo_alloc(uint32_t nbufs, int32_t socket)
{
	uint32_t i, ndb, nobj;
	size_t dsz, osz, sz;
	struct ofo *ofo;
	struct rte_mbuf **obj;

	calc_ofo_elems(nbufs, &nobj, &ndb);
	osz = sizeof(*ofo) + sizeof(ofo->db[0]) * ndb;
	dsz = sizeof(ofo->db[0].obj[0]) * nobj * ndb;
	sz = osz + dsz;

	ofo = rte_zmalloc_socket(NULL, sz, RTE_CACHE_LINE_SIZE, socket);
	if (ofo == NULL) {
		TCP_LOG(ERR, "%s: allocation of %zu bytes on socket %d "
			"failed with error code: %d\n",
			__func__, sz, socket, rte_errno);
		return NULL;
	}

	obj = (struct rte_mbuf **)&ofo->db[ndb];
	for (i = 0; i != ndb; i++) {
		ofo->db[i].nb_max = nobj;
		ofo->db[i].obj = obj + i * nobj;
	}

	ofo->nb_max = ndb;
	return ofo;
}