openwrt/target/linux/layerscape/patches-5.4/701-net-0071-sdk_dpaa-ceetm-drain-the-ceetm-CQs-on-destroy.patch

From fe7ed61721646077de5eb06a105e60634374a00c Mon Sep 17 00:00:00 2001
From: Camelia Groza <camelia.groza@nxp.com>
Date: Thu, 31 May 2018 10:45:50 +0300
Subject: [PATCH] sdk_dpaa: ceetm: drain the ceetm CQs on destroy

The CEETM CQs must be empty when configured. To guarantee this, stop all
transmissions and wait for them to drain before releasing them. On the
next configuration, we are certain they will be empty.

Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
---
 .../ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c   | 62 ++++++++++++++++++++++
 1 file changed, 62 insertions(+)

--- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
+++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
@@ -90,6 +90,51 @@ static void dpaa_drain_fqs(struct net_de
 	}
 }
 
+/* Wait for the DPAA CEETM TX CQs to empty */
+static void ceetm_drain_class(struct ceetm_class *cl)
+{
+	struct qm_mcr_ceetm_cq_query cq_query;
+	struct qm_ceetm_cq *cq;
+	unsigned int idx;
+	int ret;
+
+	if (!cl)
+		return;
+
+	switch (cl->type) {
+	case CEETM_ROOT:
+		/* The ROOT classes aren't directly linked to CEETM CQs */
+		return;
+	case CEETM_PRIO:
+		cq = (struct qm_ceetm_cq*)cl->prio.cq;
+		break;
+	case CEETM_WBFS:
+		cq = (struct qm_ceetm_cq*)cl->wbfs.cq;
+		break;
+	}
+
+	if (!cq || !cl->ch)
+		return;
+
+	/* Build the query CQID by merging the channel and the CQ IDs */
+	idx = (cq->parent->idx << 4) | cq->idx;
+
+	while (true) {
+		ret = qman_ceetm_query_cq(idx,
+					  cl->ch->dcp_idx,
+					  &cq_query);
+		if (unlikely(ret)) {
+			pr_err(KBUILD_BASENAME
+			       " : %s : unable to query CQ %x: %d\n",
+			       __func__, idx, ret);
+			break;
+		}
+
+		if (cq_query.frm_cnt == 0)
+			break;
+	}
+}
+
 /* Enqueue Rejection Notification callback */
 static void ceetm_ern(struct qman_portal *portal, struct qman_fq *fq,
 		      const struct qm_mr_entry *msg)
@@ -376,6 +421,8 @@ static void ceetm_link_class(struct Qdis
 /* Destroy a ceetm class */
 static void ceetm_cls_destroy(struct Qdisc *sch, struct ceetm_class *cl)
 {
+	struct net_device *dev = qdisc_dev(sch);
+
 	if (!cl)
 		return;
 
@@ -402,6 +449,12 @@ static void ceetm_cls_destroy(struct Qdi
 			cl->prio.child = NULL;
 		}
 
+		/* We must make sure the CQ is empty before releasing it.
+		 * Pause all transmissions while we wait for it to drain.
+		 */
+		netif_tx_stop_all_queues(dev);
+		ceetm_drain_class(cl);
+
 		if (cl->prio.lfq && qman_ceetm_lfq_release(cl->prio.lfq))
 			pr_err(KBUILD_BASENAME
 			       " : %s : error releasing the LFQ %d\n",
@@ -422,9 +475,16 @@ static void ceetm_cls_destroy(struct Qdi
 		if (cl->prio.cstats)
 			free_percpu(cl->prio.cstats);
 
+		netif_tx_wake_all_queues(dev);
 		break;
 
 	case CEETM_WBFS:
+		/* We must make sure the CQ is empty before releasing it.
+		 * Pause all transmissions while we wait for it to drain.
+		 */
+		netif_tx_stop_all_queues(dev);
+		ceetm_drain_class(cl);
+
 		if (cl->wbfs.lfq && qman_ceetm_lfq_release(cl->wbfs.lfq))
 			pr_err(KBUILD_BASENAME
 			       " : %s : error releasing the LFQ %d\n",
@@ -444,6 +504,8 @@ static void ceetm_cls_destroy(struct Qdi
 
 		if (cl->wbfs.cstats)
 			free_percpu(cl->wbfs.cstats);
+
+		netif_tx_wake_all_queues(dev);
 	}
 
 	tcf_block_put(cl->block);