Re: [PATCH net-next 5/6] net: dsa: mv88e6xxx: add helper for switch ready

[Vivien Didelot]

Hi Andrew,

Andrew Lunn  writes:

> As we have seen in the past, this sort of loop is broken if we end up
> sleeping for a long time. Please take the opportunity to replace it
> with one of our _wait() helpers, e.g. mv88e6xxx_g1_wait()

That won't work. the _wait() helpers are made to wait on self-clear (SC)
bits, i.e. looping until they are cleared to zero.

Here we want the opposite.

I will keep this existing wait loop for the moment and work soon on a
new patchset to rework the wait routines. We need a generic access to
test a given value against a given mask and wrappers for busy bits, etc.

>> +int mv88e6xxx_g1_init_ready(struct mv88e6xxx_chip *chip, bool *ready)
>> +{
>> +u16 val;
>> +int err;
>> +
>> +/* Check the value of the InitReady bit 11 */
>> +err = mv88e6xxx_g1_read(chip, GLOBAL_STATUS, );
>> +if (err)
>> +return err;
>> +
>> +*ready = !!(val & GLOBAL_STATUS_INIT_READY);
>
> I would actually do the wait here.

That is better indeed.

Thanks,

Vivien

Re: [PATCH net-next 5/6] net: dsa: mv88e6xxx: add helper for switch ready

[Andrew Lunn]

> +static int mv88e6xxx_wait_switch_ready(struct mv88e6xxx_chip *chip)
> +{
> + const unsigned long timeout = jiffies + 1 * HZ;
> + bool ready;
> + int err;
> +
> + /* Wait up to 1 second for switch to be ready.
> +  * The switch is ready when all units inside the device (ATU, VTU, etc.)
> +  * have finished their initialization and are ready to accept frames.
> +  */
> + while (time_before(jiffies, timeout)) {
> + err = mv88e6xxx_g1_init_ready(chip, );
> + if (err)
> + return err;
> +
> + if (ready)
> + break;
> +
> + usleep_range(1000, 2000);
> + }
> +
> + if (time_after(jiffies, timeout))
> + return -ETIMEDOUT;

As we have seen in the past, this sort of loop is broken if we end up
sleeping for a long time. Please take the opportunity to replace it
with one of our _wait() helpers, e.g. mv88e6xxx_g1_wait()

> +int mv88e6xxx_g1_init_ready(struct mv88e6xxx_chip *chip, bool *ready)
> +{
> + u16 val;
> + int err;
> +
> + /* Check the value of the InitReady bit 11 */
> + err = mv88e6xxx_g1_read(chip, GLOBAL_STATUS, );
> + if (err)
> + return err;
> +
> + *ready = !!(val & GLOBAL_STATUS_INIT_READY);

I would actually do the wait here.

> +
> + return 0;
> +}
> +

Thanks

  Andrew