Function i40e_dev_tx_queue_setup

dpdk/drivers/net/i40e/i40e_rxtx.c:2282–2492

}

int
i40e_dev_tx_queue_setup(struct rte_eth_dev *dev,
			uint16_t queue_idx,
			uint16_t nb_desc,
			unsigned int socket_id,
			const struct rte_eth_txconf *tx_conf)
{
	struct i40e_vsi *vsi;
	struct i40e_pf *pf = NULL;
	struct i40e_tx_queue *txq;
	const struct rte_memzone *tz;
	uint32_t ring_size;
	uint16_t tx_rs_thresh, tx_free_thresh;
	uint16_t reg_idx, i, base, bsf, tc_mapping;
	int q_offset;
	uint64_t offloads;

	offloads = tx_conf->offloads | dev->data->dev_conf.txmode.offloads;

	pf = I40E_DEV_PRIVATE_TO_PF(dev->data->dev_private);
	vsi = i40e_pf_get_vsi_by_qindex(pf, queue_idx);
	if (!vsi)
		return -EINVAL;
	q_offset = i40e_get_queue_offset_by_qindex(pf, queue_idx);
	if (q_offset < 0)
		return -EINVAL;
	reg_idx = vsi->base_queue + q_offset;

	if (nb_desc % I40E_ALIGN_RING_DESC != 0 ||
	    (nb_desc > I40E_MAX_RING_DESC) ||
	    (nb_desc < I40E_MIN_RING_DESC)) {
		PMD_DRV_LOG(ERR, "Number (%u) of transmit descriptors is "
			    "invalid", nb_desc);
		return -EINVAL;
	}

	/**
	 * The following two parameters control the setting of the RS bit on
	 * transmit descriptors. TX descriptors will have their RS bit set
	 * after txq->tx_rs_thresh descriptors have been used. The TX
	 * descriptor ring will be cleaned after txq->tx_free_thresh
	 * descriptors are used or if the number of descriptors required to
	 * transmit a packet is greater than the number of free TX descriptors.
	 *
	 * The following constraints must be satisfied:
	 *  - tx_rs_thresh must be greater than 0.
	 *  - tx_rs_thresh must be less than the size of the ring minus 2.
	 *  - tx_rs_thresh must be less than or equal to tx_free_thresh.
	 *  - tx_rs_thresh must be a divisor of the ring size.
	 *  - tx_free_thresh must be greater than 0.
	 *  - tx_free_thresh must be less than the size of the ring minus 3.
	 *  - tx_free_thresh + tx_rs_thresh must not exceed nb_desc.
	 *
	 * One descriptor in the TX ring is used as a sentinel to avoid a H/W
	 * race condition, hence the maximum threshold constraints. When set
	 * to zero use default values.
	 */
	tx_free_thresh = (uint16_t)((tx_conf->tx_free_thresh) ?