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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2015 Intel Corporation
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <rte_cycles.h>
#include <rte_memory.h>
#include <rte_branch_prediction.h>
#include <rte_mempool.h>
#include <rte_malloc.h>
#include <rte_mbuf.h>
#include <rte_ether.h>
#include <rte_ethdev_driver.h>
#include <rte_prefetch.h>
#include <rte_string_fns.h>
#include <rte_errno.h>
#include <rte_byteorder.h>

#include "virtio_rxtx_simple.h"

#ifndef __INTEL_COMPILER
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif

uint16_t
virtio_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts,
	uint16_t nb_pkts)
{
	struct virtnet_tx *txvq = tx_queue;
	struct virtqueue *vq = txvq->vq;
	struct virtio_hw *hw = vq->hw;
	uint16_t nb_used;
	uint16_t desc_idx;
	struct vring_desc *start_dp;
	uint16_t nb_tail, nb_commit;
	int i;
	uint16_t desc_idx_max = (vq->vq_nentries >> 1) - 1;
	uint16_t nb_tx = 0;

	if (unlikely(hw->started == 0 && tx_pkts != hw->inject_pkts))
		return nb_tx;

	nb_used = VIRTQUEUE_NUSED(vq);
	rte_compiler_barrier();

	if (nb_used >= VIRTIO_TX_FREE_THRESH)
		virtio_xmit_cleanup_simple(vq);

	nb_commit = nb_pkts = RTE_MIN((vq->vq_free_cnt >> 1), nb_pkts);
	desc_idx = (uint16_t)(vq->vq_avail_idx & desc_idx_max);
	start_dp = vq->vq_ring.desc;
	nb_tail = (uint16_t) (desc_idx_max + 1 - desc_idx);

	if (nb_commit >= nb_tail) {
		for (i = 0; i < nb_tail; i++)
			vq->vq_descx[desc_idx + i].cookie = tx_pkts[i];
		for (i = 0; i < nb_tail; i++) {
			start_dp[desc_idx].addr =
				VIRTIO_MBUF_DATA_DMA_ADDR(*tx_pkts, vq);
			start_dp[desc_idx].len = (*tx_pkts)->pkt_len;
			tx_pkts++;
			desc_idx++;
		}
		nb_commit -= nb_tail;
		desc_idx = 0;
	}
	for (i = 0; i < nb_commit; i++)
		vq->vq_descx[desc_idx + i].cookie = tx_pkts[i];
	for (i = 0; i < nb_commit; i++) {
		start_dp[desc_idx].addr =
			VIRTIO_MBUF_DATA_DMA_ADDR(*tx_pkts, vq);
		start_dp[desc_idx].len = (*tx_pkts)->pkt_len;
		tx_pkts++;
		desc_idx++;
	}

	rte_compiler_barrier();

	vq->vq_free_cnt -= (uint16_t)(nb_pkts << 1);
	vq->vq_avail_idx += nb_pkts;
	vq->vq_ring.avail->idx = vq->vq_avail_idx;
	txvq->stats.packets += nb_pkts;

	if (likely(nb_pkts)) {
		if (unlikely(virtqueue_kick_prepare(vq)))
			virtqueue_notify(vq);
	}

	return nb_pkts;
}

int __attribute__((cold))
virtio_rxq_vec_setup(struct virtnet_rx *rxq)
{
	uintptr_t p;
	struct rte_mbuf mb_def = { .buf_addr = 0 }; /* zeroed mbuf */

	mb_def.nb_segs = 1;
	mb_def.data_off = RTE_PKTMBUF_HEADROOM;
	mb_def.port = rxq->port_id;
	rte_mbuf_refcnt_set(&mb_def, 1);

	/* prevent compiler reordering: rearm_data covers previous fields */
	rte_compiler_barrier();
	p = (uintptr_t)&mb_def.rearm_data;
	rxq->mbuf_initializer = *(uint64_t *)p;

	return 0;
}

/* Stub for linkage when arch specific implementation is not available */
uint16_t __attribute__((weak))
virtio_recv_pkts_vec(void *rx_queue __rte_unused,
		     struct rte_mbuf **rx_pkts __rte_unused,
		     uint16_t nb_pkts __rte_unused)
{
	rte_panic("Wrong weak function linked by linker\n");
	return 0;
}