Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759542Ab2EPHb1 (ORCPT ); Wed, 16 May 2012 03:31:27 -0400 Received: from ch1ehsobe005.messaging.microsoft.com ([216.32.181.185]:35640 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759223Ab2EPHbZ (ORCPT ); Wed, 16 May 2012 03:31:25 -0400 X-SpamScore: 0 X-BigFish: VPS0(zzzz1202hzz8275bhz2dh2a8h668h839hd24he5bh) X-Forefront-Antispam-Report: CIP:137.71.25.57;KIP:(null);UIP:(null);IPV:NLI;H:nwd2mta2.analog.com;RD:nwd2mail11.analog.com;EFVD:NLI From: To: Ben Dooks , Wolfram Sang CC: , LKML , , Sonic Zhang Subject: [PATCH 3/8] i2c: i2c-bfin-twi: Break dead waiting loop if i2c device misbehaves. Date: Wed, 16 May 2012 15:20:21 +0800 Message-ID: <1337152826-9850-3-git-send-email-sonic.zhang@analog.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1337152826-9850-1-git-send-email-sonic.zhang@analog.com> References: <1337152826-9850-1-git-send-email-sonic.zhang@analog.com> MIME-Version: 1.0 Content-Type: text/plain X-OriginatorOrg: analog.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2039 Lines: 71 From: Sonic Zhang Some fault i2c device may hold the sda/scl line and cause i2c driver wait in the BUS busy loop. This patch breaks this potential dead loop. Signed-off-by: Sonic Zhang git-svn-id: svn://localhost/svn/linux-kernel/trunk@9291 526b6c2d-f592-4532-a319-5dd88ccb003d --- drivers/i2c/busses/i2c-bfin-twi.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 376e331..4abaf59 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -294,6 +294,8 @@ static irqreturn_t bfin_twi_interrupt_entry(int irq, void *dev_id) return IRQ_HANDLED; } +#define BFIN_TWI_BUSY_TIMEOUT 1000 + /* * One i2c master transfer */ @@ -303,12 +305,16 @@ static int bfin_twi_do_master_xfer(struct i2c_adapter *adap, struct bfin_twi_iface *iface = adap->algo_data; struct i2c_msg *pmsg; int rc = 0; + unsigned int busy_timeout = BFIN_TWI_BUSY_TIMEOUT; if (!(read_CONTROL(iface) & TWI_ENA)) return -ENXIO; - while (read_MASTER_STAT(iface) & BUSBUSY) + while (read_MASTER_STAT(iface) & BUSBUSY) { + if (--busy_timeout == 0) + return -EBUSY; yield(); + } iface->pmsg = msgs; iface->msg_num = num; @@ -403,12 +409,16 @@ int bfin_twi_do_smbus_xfer(struct i2c_adapter *adap, u16 addr, { struct bfin_twi_iface *iface = adap->algo_data; int rc = 0; + unsigned int busy_timeout = BFIN_TWI_BUSY_TIMEOUT; if (!(read_CONTROL(iface) & TWI_ENA)) return -ENXIO; - while (read_MASTER_STAT(iface) & BUSBUSY) + while (read_MASTER_STAT(iface) & BUSBUSY) { + if (--busy_timeout == 0) + return -EBUSY; yield(); + } iface->writeNum = 0; iface->readNum = 0; -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/