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>,
        Michal Kubecek <mkubecek@suse.cz>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Xiaoliang Yang <xiaoliang.yang_1@nxp.com>,
        Petr Machata <petrm@nvidia.com>,
        Danielle Ratson <danieller@nvidia.com>,
        Pranavi Somisetty <pranavi.somisetty@amd.com>,
        Harini Katakam <harini.katakam@amd.com>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        Kurt Kanzenbach <kurt@linutronix.de>,
        Gerhard Engleder <gerhard@engleder-embedded.com>,
        Ferenc Fejes <ferenc.fejes@ericsson.com>,
        Aaron Conole <aconole@redhat.com>,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 net-next 1/9] net: enetc: fix MAC Merge layer remaining enabled until a link down event
Date:   Tue, 18 Apr 2023 14:14:51 +0300
Message-Id: <20230418111459.811553-2-vladimir.oltean@nxp.com>
In-Reply-To: <20230418111459.811553-1-vladimir.oltean@nxp.com>
References: <20230418111459.811553-1-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?9zDqS0Nw8ZHMb91/0h5FCNsvWNwqslNnp6xbGXxcSgoqmpOerxxsskqXh9HW?=
 =?us-ascii?Q?vI+eZIzaZNYtQhPAQxAeKjmjZuFsFte/Uo+74FFWPu/JT6kT5sxNaOHjOAIG?=
 =?us-ascii?Q?LfOs48/57U60+a58hhKuM/l+tcbOM8zitWUcoilsXpTU3k+hbFsoK3Ye5QUP?=
 =?us-ascii?Q?4Rr3mmTzmCTF7uD5a9KyPCmEcK5MHRboqYgncARsaQGm9So5H6O5PIXPdvFp?=
 =?us-ascii?Q?nCPKW2BXCmXrZV2QfURuk9z4pSYQQCtVBtzIB31fK2AQoPivt+Jtk67Lo1pW?=
 =?us-ascii?Q?xC3WCNEtZj0VpuKvWjW6i6doE0rGSOPOmP/CaC4F1V6w6PiP2S9sYZ5K0KVs?=
 =?us-ascii?Q?hL71FKBBkipbbtCuq+YiOKWriME4wk7w/wEfM5CO2UcIdXfBz8BSeO7Fwt/m?=
 =?us-ascii?Q?Igu97vTNYVxXFWB/BvKGXNq5/hKf+6CyhAyMznnXO4ysgflqwexA8kIpwT2U?=
 =?us-ascii?Q?t679WpTvh26l1af6urNii1EXkBkr09GAXcWn8wG/vMFfDe1wBV2UlHzbzoTR?=
 =?us-ascii?Q?WhxE4h7O2AVhyPu2UYs+TH1D90wqb3Bc0z1hDv/u/sasM2EeW+zZHMyCtlkz?=
 =?us-ascii?Q?zlQSNWeVlj9JTSKTcDuIrZzUhcuxk7RkFg8KRQ4XFc1nwezNUQuGf9lna9IC?=
 =?us-ascii?Q?xozmsokgk9dbGkOOck+FjgJEX1r2AMW9g2rRB2y697uswKwXe1fBW/TO5kr3?=
 =?us-ascii?Q?5c5sxj/Zzyw7YSCdUOZdCTHSXLXZSUslC2mswyOkaaKWmZayiuwS+mBZqVAX?=
 =?us-ascii?Q?WqpfMlqg56UucG0QBorcUu3fb4sc3PdJEoHdsInYrtOdHdcgt4exViE9Lj8U?=
 =?us-ascii?Q?9uEUn0sGrp14+jSXYQ2DIeb6Vx+dTgT+u5wzC6QnhXvtljJpl5iQ38Iceqdk?=
 =?us-ascii?Q?XJMTLgovUk5sKioAB1lYCYcN4F1ZiWrbSu4cWc1+FI5QdFF1n8izdcASK5PH?=
 =?us-ascii?Q?ltSp6D9GkogMuHhgtMylzSGv5Hwr6dohi/Vdu/DdbM1e7IU/xcOZz3KiZCYd?=
 =?us-ascii?Q?gdBAouJj4l37w4VRhD6eWqXUJQufwoDkpfg/Z6xM7IjBHjGwHgnFT36CvEjd?=
 =?us-ascii?Q?93QR5jeIaH5BPd1rsWBkT5Uh89LfbTm8DYzp3lYYw2Wif/DPvZ8jQOmcEvEj?=
 =?us-ascii?Q?CPQYiILNh0AmZ0dw+lh6UrSbgm8JcgJvt2mJtuZ3ds3mKX7Pw/9iLiKOWAbQ?=
 =?us-ascii?Q?EpnFu6RYzWfd6w9xYms9/0MBhbhrZp/c7K6hdk+ZFUhW4rVZFTDUTW0HC0vA?=
 =?us-ascii?Q?r0odPK0t2gQvw9ID8a+kdBP+CDqYppWf6Ly7MGQvtdrVvCXmqvmOo4XvbSBT?=
 =?us-ascii?Q?taTccZJHRNSIzTsCojtT04lZmin4mjm6xDQOA5bitm0XFgtahEvS0IEW+BMo?=
 =?us-ascii?Q?/1m9bq3lnIKg4w4k1E00bP3o3teIpnPyhO59df/Zc1H7jhd2wiigZgxMAMmL?=
 =?us-ascii?Q?tJkdUbVsEoUWKhUx3KRJHAAZftn0Ab5PiTg68NKBqlTRDSScpGAJavh2SQgg?=
 =?us-ascii?Q?1USskxCViX7pYnXH9p6Y7AjGq/TfHk3Wq8Ohl/vhM0yFxJtGufCuEra3JsNa?=
 =?us-ascii?Q?Ng4zAIhiI8rFARmWM3CW3l5/bdpiLSo8FXxAPibgwF8G0VU6pQ5IZy8DwYAj?=
 =?us-ascii?Q?4Q=3D=3D?=
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 33d3fdc7-0760-40fb-2923-08db3ffe304e
X-MS-Exchange-CrossTenant-AuthSource: AM0PR04MB6452.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Apr 2023 11:15:16.9531
 (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: FdRcqIHMuCeUrQPPAoocNdIBSIVNXhgGT+NJgETVXNwYHkt8Lb1j6REcQfWbcZc7IpUnHJ5qEhGCLsFw9jYpTA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR04MB7863
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE,
        URIBL_BLOCKED autolearn=ham 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

Current enetc_set_mm() is designed to set the priv->active_offloads bit
ENETC_F_QBU for enetc_mm_link_state_update() to act on, but if the link
is already up, it modifies the ENETC_MMCSR_ME ("Merge Enable") bit
directly.

The problem is that it only *sets* ENETC_MMCSR_ME if the link is up, it
doesn't *clear* it if needed. So subsequent enetc_get_mm() calls still
see tx-enabled as true, up until a link down event, which is when
enetc_mm_link_state_update() will get called.

This is not a functional issue as far as I can assess. It has only come
up because I'd like to uphold a simple API rule in core ethtool code:
the pMAC cannot be disabled if TX is going to be enabled. Currently,
the fact that TX remains enabled for longer than expected (after the
enetc_set_mm() call that disables it) is going to violate that rule,
which is how it was caught.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: none

 drivers/net/ethernet/freescale/enetc/enetc_ethtool.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
index 838750a03cf6..ee1ea71fe79e 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
@@ -1041,10 +1041,13 @@ static int enetc_set_mm(struct net_device *ndev, struct ethtool_mm_cfg *cfg,
 	else
 		priv->active_offloads &= ~ENETC_F_QBU;
 
-	/* If link is up, enable MAC Merge right away */
-	if (!!(priv->active_offloads & ENETC_F_QBU) &&
-	    !(val & ENETC_MMCSR_LINK_FAIL))
-		val |= ENETC_MMCSR_ME;
+	/* If link is up, enable/disable MAC Merge right away */
+	if (!(val & ENETC_MMCSR_LINK_FAIL)) {
+		if (!!(priv->active_offloads & ENETC_F_QBU))
+			val |= ENETC_MMCSR_ME;
+		else
+			val &= ~ENETC_MMCSR_ME;
+	}
 
 	val &= ~ENETC_MMCSR_VT_MASK;
 	val |= ENETC_MMCSR_VT(cfg->verify_time);
-- 
2.34.1