From: Sonic Zhang <[email protected]> Some faulty i2c slave devices might hold the sda/scl line and cause the i2c bus driver to wait indefinitely in the busbusy loop. Add a timeout to the loop so the bus master can recover without locking up everything.
Signed-off-by: Sonic Zhang <[email protected]> Signed-off-by: Mike Frysinger <[email protected]> --- 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 64d4b64..f2628a7 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -288,6 +288,8 @@ 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 */ @@ -297,12 +299,16 @@ 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; @@ -397,12 +403,16 @@ 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; -- 1.7.5.rc3 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
