Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751512AbcL0GiQ (ORCPT ); Tue, 27 Dec 2016 01:38:16 -0500 Received: from mga07.intel.com ([134.134.136.100]:10480 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747AbcL0GiI (ORCPT ); Tue, 27 Dec 2016 01:38:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,415,1477983600"; d="scan'208";a="802574436" From: "Kweh, Hock Leong" To: "David S. Miller" , Joao Pinto , Giuseppe CAVALLARO , seraphin.bonnaffe@st.com, f.fainelli@gmail.com Cc: Alexandre TORGUE , Joachim Eastwood , Niklas Cassel , Johan Hovold , pavel@ucw.cz, Ong Boon Leong , "Kweh, Hock Leong" , weifeng.voon@intel.com, lars.persson@axis.com, netdev@vger.kernel.org, LKML Subject: [PATCH v2] net: stmmac: bug fix to synchronize stmmac_open and stmmac_dvr_probe Date: Tue, 27 Dec 2016 22:42:36 +0800 Message-Id: <1482849756-21817-1-git-send-email-hock.leong.kweh@intel.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3281 Lines: 82 From: "Kweh, Hock Leong" If kernel module stmmac driver being loaded after OS booted, there is a race condition between stmmac_open() and stmmac_mdio_register(), which is invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as PHY not found and stmmac_open() failed: [ 473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): stmmac_dvr_probe: warning: cannot get CSR clock [ 473.919382] stmmaceth 0000:01:00.0: no reset control found [ 473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42 [ 473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported [ 473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported [ 473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported [ 473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): Enable RX Mitigation via HW Watchdog Timer [ 473.921395] libphy: PHY stmmac-1:00 not found [ 473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY [ 473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to PHY (error: -19) [ 473.959710] libphy: stmmac: probed [ 473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL (stmmac-1:00) active [ 473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL (stmmac-1:01) [ 473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL (stmmac-1:02) [ 473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL (stmmac-1:03) The resolution moved the register_netdev() function call to the end of stmmac_dvr_probe() after stmmac_mdio_register(). Suggested-by: Florian Fainelli Signed-off-by: Kweh, Hock Leong --- changelog v2: * Re-implemented the fix base on David & Florian suggestion and tested. drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index bb40382..263ac53 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -3339,13 +3339,6 @@ int stmmac_dvr_probe(struct device *device, spin_lock_init(&priv->lock); - ret = register_netdev(ndev); - if (ret) { - netdev_err(priv->dev, "%s: ERROR %i registering the device\n", - __func__, ret); - goto error_netdev_register; - } - /* If a specific clk_csr value is passed from the platform * this means that the CSR Clock Range selection cannot be * changed at run-time and it is fixed. Viceversa the driver'll try to @@ -3372,11 +3365,18 @@ int stmmac_dvr_probe(struct device *device, } } + ret = register_netdev(ndev); + if (ret) { + netdev_err(priv->dev, "%s: ERROR %i registering the device\n", + __func__, ret); + goto error_netdev_register; + } + return 0; -error_mdio_register: - unregister_netdev(ndev); error_netdev_register: + stmmac_mdio_unregister(ndev); +error_mdio_register: netif_napi_del(&priv->napi); error_hw_init: clk_disable_unprepare(priv->pclk); -- 1.7.9.5