On Thu, Mar 25, 2010 at 04:38:09 +0200, Aaro Koskinen wrote:
> Hi,
>
> Alexander Shishkin wrote:
> > The errata 1.153 workaround is busy waiting on XUDF bit in interrupt
> > context, which may lead to kernel hangs. The problem can be reproduced
> > by running the bus with wrong (too high) speed.
> >
> > Signed-off-by: Alexander Shishkin <virtuoso@xxxxxxxxx>
> > Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>
> > CC: linux-i2c@xxxxxxxxxxxxxxx
> > CC: linux-omap@xxxxxxxxxxxxxxx
> > CC: nm@xxxxxx
> > ---
> > drivers/i2c/busses/i2c-omap.c | 8 ++++++++
> > 1 files changed, 8 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> > index 2d146ac..7d56a25 100644
> > --- a/drivers/i2c/busses/i2c-omap.c
> > +++ b/drivers/i2c/busses/i2c-omap.c
> > @@ -678,6 +678,8 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
> > */
> > static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
> > {
> > + unsigned long timeout = jiffies + msecs_to_jiffies(1);
> > +
> > while (!(*stat & OMAP_I2C_STAT_XUDF)) {
> > if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
> > omap_i2c_ack_stat(dev, *stat & (OMAP_I2C_STAT_XRDY |
> > @@ -685,6 +687,12 @@ static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
> > *err |= OMAP_I2C_STAT_XUDF;
> > return -ETIMEDOUT;
> > }
> > +
> > + if (time_after(jiffies, timeout)) {
>
> This is called from hard interrupt context, so we cannot use jiffies.
Ahh, stupid me. Then we are left with the iteration counting, I guess.
Regards,
--
Alex
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