From patchwork Mon Nov 29 18:18:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 519041 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDFD4C433EF for ; Mon, 29 Nov 2021 18:33:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379774AbhK2ShC (ORCPT ); Mon, 29 Nov 2021 13:37:02 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:52660 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378749AbhK2SfB (ORCPT ); Mon, 29 Nov 2021 13:35:01 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 60118CE13AA; Mon, 29 Nov 2021 18:31:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E0EBC53FC7; Mon, 29 Nov 2021 18:31:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638210700; bh=hJtRomHVfhrSx2NalxNrW4QcfScJCGqMg3uyVbIElrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DBGKgFF1M5qisO/O7mS7Hk1QYZFgigr84LE9dfXvhmPNKsDzlWwrmnpe7h1Z1OOsk KslEBBllhGSARYwBkG99boV+PvCvZ3iaFi/3MpBEr0WWUrcHlL42+uWRdHv6aKxw3B KwHdP1+iKLphZNHKHR+2aWp+qb8vNgojGTcHcTww= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Russell King (Oracle)" , =?utf-8?q?Marek_Beh?= =?utf-8?q?=C3=BAn?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 086/121] net: phylink: Force retrigger in case of latched link-fail indicator Date: Mon, 29 Nov 2021 19:18:37 +0100 Message-Id: <20211129181714.555135358@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211129181711.642046348@linuxfoundation.org> References: <20211129181711.642046348@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Russell King (Oracle) [ Upstream commit dbae3388ea9ca33bd1d5eabc3b0ef17e69c74677 ] On mv88e6xxx 1G/2.5G PCS, the SerDes register 4.2001.2 has the following description: This register bit indicates when link was lost since the last read. For the current link status, read this register back-to-back. Thus to get current link state, we need to read the register twice. But doing that in the link change interrupt handler would lead to potentially ignoring link down events, which we really want to avoid. Thus this needs to be solved in phylink's resolve, by retriggering another resolve in the event when PCS reports link down and previous link was up, and by re-reading PCS state if the previous link was down. The wrong value is read when phylink requests change from sgmii to 2500base-x mode, and link won't come up. This fixes the bug. Fixes: 9525ae83959b ("phylink: add phylink infrastructure") Signed-off-by: Russell King (Oracle) Signed-off-by: Marek Behún Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/phy/phylink.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c index 8279e08dad9db..57b1b138522e0 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -675,6 +675,19 @@ static void phylink_resolve(struct work_struct *w) case MLO_AN_INBAND: phylink_mac_pcs_get_state(pl, &link_state); + /* The PCS may have a latching link-fail indicator. + * If the link was up, bring the link down and + * re-trigger the resolve. Otherwise, re-read the + * PCS state to get the current status of the link. + */ + if (!link_state.link) { + if (cur_link_state) + retrigger = true; + else + phylink_mac_pcs_get_state(pl, + &link_state); + } + /* If we have a phy, the "up" state is the union of * both the PHY and the MAC */ if (pl->phydev)