Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH net] net: enetc: preserve TX ring priority across reconfiguration
Date:   Tue, 22 Nov 2022 15:09:36 +0200
Message-Id: <20221122130936.1704151-1-vladimir.oltean@nxp.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?WXMy0CtI07Uk+rW4BCuvXf23FdTDQVZByrd8mKgCq1XGyvLg5rZt9s9VVPGj?=
 =?us-ascii?Q?A0EWD23UheNzEkfeXFIVwsvUEFk0ndbm3d+KK6qkr3bzju9Zt3dqb6pjb/NZ?=
 =?us-ascii?Q?x8zPhlyDehEuiwqaxQPo+jv06ZyiqYfDZtko7RoK4wGa5LHIn34FVN/rGTDB?=
 =?us-ascii?Q?IdVx5P0vUI6RcoO4GqiW7UDhZn7qMg+wYZDarU6qmX4XNlqLiv6FH6l0L7mg?=
 =?us-ascii?Q?0GugrcvpwN9obmoEe5/Vj6d6OnxVBmNYCy02IjgcDrxllgWhtCeP/HAoaQPT?=
 =?us-ascii?Q?buGXk/ofkKVcu0fGi4IbExUwnbcruk1fMBgxVzKpPzTIwzCsGnleHeaqiiFK?=
 =?us-ascii?Q?440dtQe0DahP37byjyX5VkyuMUtM8oQRiz1Yz0Z3Sz5Gzz7eP63uf1I+hbPt?=
 =?us-ascii?Q?xqKVH4fGpS/DVI1VMaZ6Pr0+QTYvnjwROGkz3jOdjSll4BNhRV+ZzKsIRsU6?=
 =?us-ascii?Q?L2NWRGiR259oGigUpM0dRtqQ+ahKYqhHrjPq+8dte8q2vfECklSrM2XLQZjC?=
 =?us-ascii?Q?ynfRHzwCklwbe1ixQNyW0VYTuDEdCbeIS7DzD95RQtS1mvOIbLDhgT3u1A0K?=
 =?us-ascii?Q?x/UBhEJRGpZybapnC5qCWckeexptY3V5vQwooGoXhMymLJWFnbslRwFRJWeg?=
 =?us-ascii?Q?zQKuOs9Kqt1O7cinZfKlxotzE4wlF1iXs7i/e2gekBuarox6lG8uWmq39mpy?=
 =?us-ascii?Q?ISnukoQ9kldNHe7mc7ql9YGbeYey+p47YSCfF19piY4NXLlwnlZDLYcPzR+w?=
 =?us-ascii?Q?Bk6PNCEtVJS85sJKu9udUmBB3j/3Yteg0UkYHvPhT5znGGAO0aShfW4TqjpN?=
 =?us-ascii?Q?RmbxWoISQG/NbInAeFpfIRZRBB5ZiLB0d4LGuICXJooCTz4NzBWBOhubjqla?=
 =?us-ascii?Q?3peSy8ScM1YRnY6R2rBBbKSedRY9QQmkZAnzWJNuf4c2ny1tj4xi4QgMk53i?=
 =?us-ascii?Q?GH//zH3CJa+PP8QZqWDnp3jmCcbRbcYWTuZG+oKn60EOGeNsJI1ByIKtXukQ?=
 =?us-ascii?Q?fN7ite6NEcsxU8kWkBfdctJcKduj+RnxtcoMBxSqEmWWl9hD6TiCR8c/yx9o?=
 =?us-ascii?Q?1F7je63YyQMdTKRM1Yz70sb1s8RBDJe8lOB3E087p8oZ3fd451hbbAxp1BvG?=
 =?us-ascii?Q?70QG653Wp4F02EfdyGzUrfGRnhvbqlNQ/hQ9Sh6+Yw/jhHoZHC81VxA8tug4?=
 =?us-ascii?Q?mmuffp/MkShq5YSJs7M05RgGqKJSctK3+XTESz7GP+VOl+AhVzTQ9KY27nbu?=
 =?us-ascii?Q?iZm+wbefgzh/yoaOlGzpwi5013eva5fSOxticBqNvFfp2pEO0jlw/ENqiJTB?=
 =?us-ascii?Q?Nt9NVQxkXn3wIui8/qWTQxdCv2xuYMSmcYXxL99zO13UGkGKeJoRyzOAAkr+?=
 =?us-ascii?Q?Px77gXHV6kxBj6TX/zQndqnK/rpkqPjE4nixGLLjVRtjbx9LyNBJ9xnwzXNP?=
 =?us-ascii?Q?Z6Fr2AMM2pvJmbnTsyiy16OzvQjQQ6iSBIQ4w6e0nnTbMNkW/pQhi2IV0pvJ?=
 =?us-ascii?Q?twoNfS5RQKHCnc9B/vUxDPFRORgj7jQ5Efp59Tm2cbeHT86NslAztV9bQYH+?=
 =?us-ascii?Q?cisZUyrah6u17mg1qEzS8V9nzKVe3WWYHn6kFDaKqYtrQwVHL6MuqKBjboqB?=
 =?us-ascii?Q?2w=3D=3D?=
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 0e4ad879-334a-40cf-4bcf-08dacc8af6e9
X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5136.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Nov 2022 13:10:44.8571
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 2ZoZcwcseY6aTCI6kRNtKGbJdClidHw+z3f1LeTI0tQeT/kzkW2gcozO+M8GovgCxNkpoW6maiRyUio0ch9CqA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR04MB8030
X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,SPF_HELO_PASS,
        T_SPF_PERMERROR autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

In the blamed commit, a rudimentary reallocation procedure for RX buffer
descriptors was implemented, for the situation when their format changes
between normal (no PTP) and extended (PTP).

enetc_hwtstamp_set() calls enetc_close() and enetc_open() in a sequence,
and this sequence loses information which was previously configured in
the TX BDR Mode Register, specifically via the enetc_set_bdr_prio() call.
The TX ring priority is configured by tc-mqprio and tc-taprio, and
affects important things for TSN such as the TX time of packets. The
issue manifests itself most visibly by the fact that isochron --txtime
reports premature packet transmissions when PTP is first enabled on an
enetc interface.

Save the TX ring priority in a new field in struct enetc_bdr (occupies a
2 byte hole on arm64) in order to make this survive a ring reconfiguration.

Fixes: 434cebabd3a2 ("enetc: Add dynamic allocation of extended Rx BD rings")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/ethernet/freescale/enetc/enetc.c  |  8 ++++---
 drivers/net/ethernet/freescale/enetc/enetc.h  |  1 +
 .../net/ethernet/freescale/enetc/enetc_qos.c  | 21 ++++++++++++-------
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index b4988fe6bb93..9c0ab983b6e9 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -2061,7 +2061,7 @@ static void enetc_setup_txbdr(struct enetc_hw *hw, struct enetc_bdr *tx_ring)
 	/* enable Tx ints by setting pkt thr to 1 */
 	enetc_txbdr_wr(hw, idx, ENETC_TBICR0, ENETC_TBICR0_ICEN | 0x1);
 
-	tbmr = ENETC_TBMR_EN;
+	tbmr = ENETC_TBMR_EN | ENETC_TBMR_SET_PRIO(tx_ring->prio);
 	if (tx_ring->ndev->features & NETIF_F_HW_VLAN_CTAG_TX)
 		tbmr |= ENETC_TBMR_VIH;
 
@@ -2464,7 +2464,8 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 		/* Reset all ring priorities to 0 */
 		for (i = 0; i < priv->num_tx_rings; i++) {
 			tx_ring = priv->tx_ring[i];
-			enetc_set_bdr_prio(hw, tx_ring->index, 0);
+			tx_ring->prio = 0;
+			enetc_set_bdr_prio(hw, tx_ring->index, tx_ring->prio);
 		}
 
 		return 0;
@@ -2483,7 +2484,8 @@ int enetc_setup_tc_mqprio(struct net_device *ndev, void *type_data)
 	 */
 	for (i = 0; i < num_tc; i++) {
 		tx_ring = priv->tx_ring[i];
-		enetc_set_bdr_prio(hw, tx_ring->index, i);
+		tx_ring->prio = i;
+		enetc_set_bdr_prio(hw, tx_ring->index, tx_ring->prio);
 	}
 
 	/* Reset the number of netdev queues based on the TC count */
diff --git a/drivers/net/ethernet/freescale/enetc/enetc.h b/drivers/net/ethernet/freescale/enetc/enetc.h
index ea3ceed5bfa9..40bcd68c0c49 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc.h
@@ -95,6 +95,7 @@ struct enetc_bdr {
 		void __iomem *rcir;
 	};
 	u16 index;
+	u16 prio;
 	int bd_count; /* # of BDs */
 	int next_to_use;
 	int next_to_clean;
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_qos.c b/drivers/net/ethernet/freescale/enetc/enetc_qos.c
index a842e1999122..fcebb54224c0 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_qos.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_qos.c
@@ -137,6 +137,7 @@ int enetc_setup_tc_taprio(struct net_device *ndev, void *type_data)
 	struct tc_taprio_qopt_offload *taprio = type_data;
 	struct enetc_ndev_priv *priv = netdev_priv(ndev);
 	struct enetc_hw *hw = &priv->si->hw;
+	struct enetc_bdr *tx_ring;
 	int err;
 	int i;
 
@@ -145,16 +146,20 @@ int enetc_setup_tc_taprio(struct net_device *ndev, void *type_data)
 		if (priv->tx_ring[i]->tsd_enable)
 			return -EBUSY;
 
-	for (i = 0; i < priv->num_tx_rings; i++)
-		enetc_set_bdr_prio(hw, priv->tx_ring[i]->index,
-				   taprio->enable ? i : 0);
+	for (i = 0; i < priv->num_tx_rings; i++) {
+		tx_ring = priv->tx_ring[i];
+		tx_ring->prio = taprio->enable ? i : 0;
+		enetc_set_bdr_prio(hw, tx_ring->index, tx_ring->prio);
+	}
 
 	err = enetc_setup_taprio(ndev, taprio);
-
-	if (err)
-		for (i = 0; i < priv->num_tx_rings; i++)
-			enetc_set_bdr_prio(hw, priv->tx_ring[i]->index,
-					   taprio->enable ? 0 : i);
+	if (err) {
+		for (i = 0; i < priv->num_tx_rings; i++) {
+			tx_ring = priv->tx_ring[i];
+			tx_ring->prio = taprio->enable ? 0 : i;
+			enetc_set_bdr_prio(hw, tx_ring->index, tx_ring->prio);
+		}
+	}
 
 	return err;
 }
-- 
2.34.1