From patchwork Tue Nov 23 15:44:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 12634519 X-Patchwork-Delegate: kuba@kernel.org 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 75280C433EF for ; Tue, 23 Nov 2021 15:44:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236345AbhKWPrU (ORCPT ); Tue, 23 Nov 2021 10:47:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:34892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236330AbhKWPrT (ORCPT ); Tue, 23 Nov 2021 10:47:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 56A9460F9D; Tue, 23 Nov 2021 15:44:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637682251; bh=OLhgtLiZ098SPvaox7Xvh4plbAgGDAJ9PdtCzmjKwEY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8pD31JblxsYNDLVUpVWoXlFMGsRTaDOf82cCtnuAN3ktoAN82lWGeLE7ftbJ3kOo 2XEGShyIfvzWnlwNKVOY9vJl6C5sf5RVFQ1YJkPtN9Lc3HmHhCldHOneM6+5uxcPIh 2cy7c8/2CSqfmJFOFt8lq1YyBCmp29/ktIrn2GeNY84vNgoglqcpvydNGLwwG+bXnH SBdYzVovv6lnQI/+GjI40OwD67/YW8PZSmTkMCi4lnljUV8f7gWBR+zeiy5gC4IJEI 5+nXFesvWJKsxkfeA/djxxWtdUYTCBhWMxZh1JOwQblzBYHWhPxerp9CIWWF/EFsik 1N+KN3O5NkmEw== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: netdev@vger.kernel.org Cc: Russell King , Jakub Kicinski , Andrew Lunn , davem@davemloft.net, =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH net v2 2/2] net: phylink: Force retrigger in case of latched link-fail indicator Date: Tue, 23 Nov 2021 16:44:03 +0100 Message-Id: <20211123154403.32051-3-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211123154403.32051-1-kabel@kernel.org> References: <20211123154403.32051-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: "Russell King (Oracle)" 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 --- 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 5b8b61daeb98..eacbb0e6a24b 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -994,6 +994,19 @@ 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 */