On Wed, May 16, 2012 at 03:20:21PM +0800, sonic.zhang@xxxxxxxxxx wrote:
> From: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
>
> 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 <sonic.zhang@xxxxxxxxxx>
>
> 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
> +
Please use a unit like microseconds for the timeout.
> /*
> * 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
>
>
> --
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