From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: [PATCH] can: sja1000: fix isr hang when hw is unplugged under load Date: Mon, 20 Feb 2012 11:58:32 +0100 Message-ID: <1329735512-29402-2-git-send-email-mkl@pengutronix.de> References: <1329735512-29402-1-git-send-email-mkl@pengutronix.de> Cc: netdev@vger.kernel.org, Oliver Hartkopp , Marc Kleine-Budde To: davem@davemloft.net Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:56443 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752255Ab2BTK6k (ORCPT ); Mon, 20 Feb 2012 05:58:40 -0500 In-Reply-To: <1329735512-29402-1-git-send-email-mkl@pengutronix.de> Sender: netdev-owner@vger.kernel.org List-ID: From: Oliver Hartkopp 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. Cc: stable@kernel.org [3.2+] Signed-off-by: Oliver Hartkopp Acked-by: Wolfgang Grandegger Signed-off-by: Marc Kleine-Budde --- drivers/net/can/sja1000/sja1000.c | 13 ++++++++++++- 1 files changed, 12 insertions(+), 1 deletions(-) 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)) { -- 1.7.4.1