net/mlx5e: Use dma_rmb rather than rmb in CQE fetch routine

[mirror_ubuntu-bionic-kernel.git] / drivers / net / ethernet / mellanox / mlx5 / core / en_txrx.c

/*
 * Copyright (c) 2015, Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * 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.
 */

#include "en.h"

struct mlx5_cqe64 *mlx5e_get_cqe(struct mlx5e_cq *cq)
{
	struct mlx5_cqwq *wq = &cq->wq;
	u32 ci = mlx5_cqwq_get_ci(wq);
	struct mlx5_cqe64 *cqe = mlx5_cqwq_get_wqe(wq, ci);
	int cqe_ownership_bit = cqe->op_own & MLX5_CQE_OWNER_MASK;
	int sw_ownership_val = mlx5_cqwq_get_wrap_cnt(wq) & 1;

	if (cqe_ownership_bit != sw_ownership_val)
		return NULL;

	/* ensure cqe content is read after cqe ownership bit */
	dma_rmb();

	return cqe;
}

static void mlx5e_poll_ico_cq(struct mlx5e_cq *cq)
{
	struct mlx5e_sq *sq = container_of(cq, struct mlx5e_sq, cq);
	struct mlx5_wq_cyc *wq;
	struct mlx5_cqe64 *cqe;
	u16 sqcc;

	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))
		return;

	cqe = mlx5e_get_cqe(cq);
	if (likely(!cqe))
		return;

	wq = &sq->wq;

	/* sq->cc must be updated only after mlx5_cqwq_update_db_record(),
	 * otherwise a cq overrun may occur
	 */
	sqcc = sq->cc;

	do {
		u16 ci = be16_to_cpu(cqe->wqe_counter) & wq->sz_m1;
		struct mlx5e_sq_wqe_info *icowi = &sq->db.ico_wqe[ci];

		mlx5_cqwq_pop(&cq->wq);
		sqcc += icowi->num_wqebbs;

		if (unlikely((cqe->op_own >> 4) != MLX5_CQE_REQ)) {
			WARN_ONCE(true, "mlx5e: Bad OP in ICOSQ CQE: 0x%x\n",
				  cqe->op_own);
			break;
		}

		switch (icowi->opcode) {
		case MLX5_OPCODE_NOP:
			break;
		case MLX5_OPCODE_UMR:
			mlx5e_post_rx_mpwqe(&sq->channel->rq);
			break;
		default:
			WARN_ONCE(true,
				  "mlx5e: Bad OPCODE in ICOSQ WQE info: 0x%x\n",
				  icowi->opcode);
		}

	} while ((cqe = mlx5e_get_cqe(cq)));

	mlx5_cqwq_update_db_record(&cq->wq);

	/* ensure cq space is freed before enabling more cqes */
	wmb();

	sq->cc = sqcc;
}

static inline bool mlx5e_poll_xdp_tx_cq(struct mlx5e_cq *cq)
{
	struct mlx5e_sq *sq;
	u16 sqcc;
	int i;

	sq = container_of(cq, struct mlx5e_sq, cq);

	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))
		return false;

	/* sq->cc must be updated only after mlx5_cqwq_update_db_record(),
	 * otherwise a cq overrun may occur
	 */
	sqcc = sq->cc;

	for (i = 0; i < MLX5E_TX_CQ_POLL_BUDGET; i++) {
		struct mlx5_cqe64 *cqe;
		u16 wqe_counter;
		bool last_wqe;

		cqe = mlx5e_get_cqe(cq);
		if (!cqe)
			break;

		mlx5_cqwq_pop(&cq->wq);

		wqe_counter = be16_to_cpu(cqe->wqe_counter);

		do {
			struct mlx5e_sq_wqe_info *wi;
			struct mlx5e_dma_info *di;
			u16 ci;

			last_wqe = (sqcc == wqe_counter);

			ci = sqcc & sq->wq.sz_m1;
			di = &sq->db.xdp.di[ci];
			wi = &sq->db.xdp.wqe_info[ci];

			if (unlikely(wi->opcode == MLX5_OPCODE_NOP)) {
				sqcc++;
				continue;
			}

			sqcc += wi->num_wqebbs;
			/* Recycle RX page */
			mlx5e_page_release(&sq->channel->rq, di, true);
		} while (!last_wqe);
	}

	mlx5_cqwq_update_db_record(&cq->wq);

	/* ensure cq space is freed before enabling more cqes */
	wmb();

	sq->cc = sqcc;
	return (i == MLX5E_TX_CQ_POLL_BUDGET);
}

int mlx5e_napi_poll(struct napi_struct *napi, int budget)
{
	struct mlx5e_channel *c = container_of(napi, struct mlx5e_channel,
					       napi);
	bool busy = false;
	int work_done;
	int i;

	clear_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags);

	for (i = 0; i < c->num_tc; i++)
		busy |= mlx5e_poll_tx_cq(&c->sq[i].cq, budget);

	work_done = mlx5e_poll_rx_cq(&c->rq.cq, budget);
	busy |= work_done == budget;

	if (c->xdp)
		busy |= mlx5e_poll_xdp_tx_cq(&c->xdp_sq.cq);

	mlx5e_poll_ico_cq(&c->icosq.cq);

	busy |= mlx5e_post_rx_wqes(&c->rq);

	if (busy)
		return budget;

	napi_complete_done(napi, work_done);

	/* avoid losing completion event during/after polling cqs */
	if (test_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags)) {
		napi_schedule(napi);
		return work_done;
	}

	for (i = 0; i < c->num_tc; i++)
		mlx5e_cq_arm(&c->sq[i].cq);

	if (test_bit(MLX5E_RQ_STATE_AM, &c->rq.state))
		mlx5e_rx_am(&c->rq);

	mlx5e_cq_arm(&c->rq.cq);
	mlx5e_cq_arm(&c->icosq.cq);

	return work_done;
}

void mlx5e_completion_event(struct mlx5_core_cq *mcq)
{
	struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq);

	cq->event_ctr++;
	set_bit(MLX5E_CHANNEL_NAPI_SCHED, &cq->channel->flags);
	napi_schedule(cq->napi);
}

void mlx5e_cq_error_event(struct mlx5_core_cq *mcq, enum mlx5_event event)
{
	struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq);
	struct mlx5e_channel *c = cq->channel;
	struct mlx5e_priv *priv = c->priv;
	struct net_device *netdev = priv->netdev;

	netdev_err(netdev, "%s: cqn=0x%.6x event=0x%.2x\n",
		   __func__, mcq->cqn, event);
}