From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: [PATCH v2] can: sja1000 fix isr hang when hw is unplugged under load Date: Wed, 15 Feb 2012 17:51:56 +0100 Message-ID: <4F3BE2AC.9020108@hartkopp.net> References: <1318506157-10329-1-git-send-email-mkl@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mo-p00-ob.rzone.de ([81.169.146.160]:61389 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862Ab2BOQwR (ORCPT ); Wed, 15 Feb 2012 11:52:17 -0500 Received: from [109.40.207.183] (ip-109-40-207-183.web.vodafone.de [109.40.207.183]) by smtp.strato.de (jimi mo43) (RZmta 27.6 DYNA|AUTH) with ESMTPA id Q0128do1FFEwD3 for ; Wed, 15 Feb 2012 17:52:00 +0100 (MET) In-Reply-To: <1318506157-10329-1-git-send-email-mkl@pengutronix.de> Sender: linux-can-owner@vger.kernel.org List-ID: To: linux-can@vger.kernel.org In the case of hotplug enabled devices (PCMCIA/PCIeC) the removal of the hardware can cause an infinite loop in the common sja1000 isr. Use the already retrieved status register to indicate a possible hardware removal and double check by reading the mode register in sja1000_is_absent. v2: Create a new function to not print information in irq context. Signed-off-by: Oliver Hartkopp --- diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c index 04a3f1b..192b0d1 100644 --- a/drivers/net/can/sja1000/sja1000.c +++ b/drivers/net/can/sja1000/sja1000.c @@ -95,11 +95,16 @@ static void sja1000_write_cmdreg(struct sja1000_priv *priv, u8 val) spin_unlock_irqrestore(&priv->cmdreg_lock, flags); } +static int sja1000_is_absent(struct sja1000_priv *priv) +{ + return (priv->read_reg(priv, REG_MOD) == 0xFF); +} + static int sja1000_probe_chip(struct net_device *dev) { struct sja1000_priv *priv = netdev_priv(dev); - if (priv->reg_base && (priv->read_reg(priv, 0) == 0xFF)) { + if (priv->reg_base && sja1000_is_absent(priv)) { printk(KERN_INFO "%s: probing @0x%lX failed\n", DRV_NAME, dev->base_addr); return 0; @@ -493,6 +498,9 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id) while ((isrc = priv->read_reg(priv, REG_IR)) && (n < SJA1000_MAX_IRQ)) { n++; status = priv->read_reg(priv, REG_SR); + /* check for absent controller due to hw unplug */ + if (status == 0xFF && sja1000_is_absent(priv)) + return IRQ_NONE; if (isrc & IRQ_WUI) dev_warn(dev->dev.parent, "wakeup interrupt\n"); @@ -509,6 +517,9 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id) while (status & SR_RBS) { sja1000_rx(dev); status = priv->read_reg(priv, REG_SR); + /* check for absent controller */ + if (status == 0xFF && sja1000_is_absent(priv)) + return IRQ_NONE; } } if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {