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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 E8204C11F77 for ; Tue, 6 Jul 2021 11:54:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3EB261179 for ; Tue, 6 Jul 2021 11:54:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241113AbhGFL40 (ORCPT ); Tue, 6 Jul 2021 07:56:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:42496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234566AbhGFLdf (ORCPT ); Tue, 6 Jul 2021 07:33:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3341461D25; Tue, 6 Jul 2021 11:22:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625570577; bh=VOd0m6jZONjoND+jTrjgd4uo7g4q1WQ+8SkWRsDct7Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oERb9Cb16oUySdmlv7LJbK49ZAO38la9al8RCHl7VtAyoxYY3EwNeR4uY+PaHL9Vu tTIs09EqviFa4gWH/2K9UNbm4aY6KAkR9GYP3UX+/4l2ZofaY0tqvFIHHOEtcgIyTL XK4+sAgvik0O8Rdww7LRpBTDBTauFtMjOecZf3joNAYHQpeI8PhoJFlR0tAxKRUBKu GF8cO3WS1RNL4If/tnNZ3yUj1qe6RDIhNYpObBrm1LysIQCKFhTDRk+R/ZivMZBEWV MVGDuNe7MUrJ4BhY8y61xw/DFtIi4zutXMkuQtzaj1ywTN3glYE0O/4V56zk5RS/2R FGWBVtobHQD5A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vladimir Oltean , Jakub Kicinski , Sasha Levin , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 041/137] net: stmmac: the XPCS obscures a potential "PHY not found" error Date: Tue, 6 Jul 2021 07:20:27 -0400 Message-Id: <20210706112203.2062605-41-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210706112203.2062605-1-sashal@kernel.org> References: <20210706112203.2062605-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 b2a707e2ef43..678726c62a8a 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c @@ -441,6 +441,12 @@ 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; @@ -449,6 +455,7 @@ int stmmac_mdio_register(struct net_device *ndev) xpcs->bus = new_bus; + found = 0; for (addr = 0; addr < max_addr; addr++) { xpcs->addr = addr; @@ -458,13 +465,12 @@ 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: @@ -472,6 +478,9 @@ int stmmac_mdio_register(struct net_device *ndev) return 0; +no_xpcs_found: +no_phy_found: + mdiobus_unregister(new_bus); bus_register_fail: mdiobus_free(new_bus); return err; -- 2.30.2