From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4B2BC6377E for ; Thu, 15 Jul 2021 19:28:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8F5F6141A for ; Thu, 15 Jul 2021 19:28:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343629AbhGOT3c (ORCPT ); Thu, 15 Jul 2021 15:29:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:46402 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243231AbhGOTJi (ORCPT ); Thu, 15 Jul 2021 15:09:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9E0D5613D7; Thu, 15 Jul 2021 19:05:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626375921; bh=6NQfrjTCwGu0yI8QS3j8OxGNtiY/MRKl+J+5wzAbrTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2FieDg1vXIex628MO3W7n0BceyjFLU/oi/r9n/SBKYliX+gplXpYiPIpo1F96zIRg lxTHhQB0BkKxP8TI7sQyugcGrEwBbGmOF91bv3yuBd4s5BGlCXekJq/Fd/jDFNqPl1 EJUrc+SyjapsRxZ3MiiMJje5/CJPzIOJ+l33lWpY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vladimir Oltean , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.13 050/266] net: stmmac: the XPCS obscures a potential "PHY not found" error Date: Thu, 15 Jul 2021 20:36:45 +0200 Message-Id: <20210715182623.009946906@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210715182613.933608881@linuxfoundation.org> References: <20210715182613.933608881@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vladimir Oltean [ Upstream commit 4751d2aa321f2828d8c5d2f7ce4ed18a01e47f46 ] stmmac_mdio_register() has logic to search for PHYs on the MDIO bus and assign them IRQ lines, as well as to set priv->plat->phy_addr. If no PHY is found, the "found" variable remains set to 0 and the function errors out. After the introduction of commit f213bbe8a9d6 ("net: stmmac: Integrate it with DesignWare XPCS"), the "found" variable was immediately reused for searching for a PCS on the same MDIO bus. This can result in 2 types of potential problems (none of them seems to be seen on the only Intel system that sets has_xpcs = true, otherwise it would have been reported): 1. If a PCS is found but a PHY is not, then the code happily exits with no error. One might say "yes, but this is not possible, because of_mdiobus_register will probe a PHY for all MDIO addresses, including for the XPCS, so if an XPCS exists, then a PHY certainly exists too". Well, that is not true, see intel_mgbe_common_data(): /* Ensure mdio bus scan skips intel serdes and pcs-xpcs */ plat->mdio_bus_data->phy_mask = 1 << INTEL_MGBE_ADHOC_ADDR; plat->mdio_bus_data->phy_mask |= 1 << INTEL_MGBE_XPCS_ADDR; 2. A PHY is found but an MDIO device with the XPCS PHY ID isn't, and in that case, the error message will be "No PHY found". Confusing. Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20210527155959.3270478-1-olteanv@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- .../net/ethernet/stmicro/stmmac/stmmac_mdio.c | 21 +++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c index b750074f8f9c..e293bf1ce9f3 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c @@ -503,6 +503,12 @@ int stmmac_mdio_register(struct net_device *ndev) found = 1; } + if (!found && !mdio_node) { + dev_warn(dev, "No PHY found\n"); + err = -ENODEV; + goto no_phy_found; + } + /* Try to probe the XPCS by scanning all addresses. */ if (priv->hw->xpcs) { struct mdio_xpcs_args *xpcs = &priv->hw->xpcs_args; @@ -511,6 +517,7 @@ int stmmac_mdio_register(struct net_device *ndev) xpcs->bus = new_bus; + found = 0; for (addr = 0; addr < max_addr; addr++) { xpcs->addr = addr; @@ -520,13 +527,12 @@ int stmmac_mdio_register(struct net_device *ndev) break; } } - } - if (!found && !mdio_node) { - dev_warn(dev, "No PHY found\n"); - mdiobus_unregister(new_bus); - mdiobus_free(new_bus); - return -ENODEV; + if (!found && !mdio_node) { + dev_warn(dev, "No XPCS found\n"); + err = -ENODEV; + goto no_xpcs_found; + } } bus_register_done: @@ -534,6 +540,9 @@ bus_register_done: return 0; +no_xpcs_found: +no_phy_found: + mdiobus_unregister(new_bus); bus_register_fail: mdiobus_free(new_bus); return err; -- 2.30.2