Hi Jakko,
On Wed, Mar 18, 2020 at 10:19 PM Laine Jaakko EXT
<ext-jaakko.laine@xxxxxxxxxxx> wrote:
>
> Hello,
>
> >> @@ -521,19 +523,26 @@ static int xiic_bus_busy(struct xiic_i2c *i2c)
> >> static int xiic_busy(struct xiic_i2c *i2c)
> >> {
> >> int tries = 3;
> >> - int err;
> >> + int err = 0;
> >>
> >> if (i2c->tx_msg)
> >> return -EBUSY;
> >>
> >> - /* for instance if previous transfer was terminated due to TX error
> >> - * it might be that the bus is on it's way to become available
> >> - * give it at most 3 ms to wake
> >> + /* In single master mode bus can only be busy, when in use by this
> >> + * driver. If the register indicates bus being busy for some reason we
> >> + * should ignore it, since bus will never be released and i2c will be
> >> + * stuck forever.
> >> */
> >
> >the other thing i was thinking how will multithreading .
> >Should we have a lock here.
> >
> >> - err = xiic_bus_busy(i2c);
> >> - while (err && tries--) {
> >> - msleep(1);
> >> + if (i2c->multimaster) {
> >> + /* for instance if previous transfer was terminated due to TX
> >> + * error it might be that the bus is on it's way to become
> >> + * available give it at most 3 ms to wake
> >> + */
> >> err = xiic_bus_busy(i2c);
> >> + while (err && tries--) {
> >> + msleep(1);
> >> + err = xiic_bus_busy(i2c);
> >> + }
> >> }
> >>
> >> return err;
>
> Which resource specifically are you worried about needing locking here?
>
Earlier multiple threads on the same processor will wait for bus busy.
Now my concern was
thread1 -> makes a transaction
thread2 -> this will not wait for bus busy and access.
