Re: [PATCH 7/7] net: dsa: b53: Expose PTP timestamping ioctls to userspace

From: Kurt Kanzenbach
Date: Fri Nov 26 2021 - 03:48:27 EST


On Thu Nov 25 2021, Vladimir Oltean wrote:
> On Mon, Nov 08, 2021 at 06:48:24AM -0800, Richard Cochran wrote:
>> On Sun, Nov 07, 2021 at 04:27:03PM +0200, Vladimir Oltean wrote:
>> > On Sun, Nov 07, 2021 at 06:05:34AM -0800, Richard Cochran wrote:
>> > > switch (cfg.rx_filter) {
>> > > case HWTSTAMP_FILTER_NONE:
>> > > break;
>> > > case HWTSTAMP_FILTER_ALL:
>> > > case HWTSTAMP_FILTER_SOME:
>> > > case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
>> > > case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
>> > > case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
>> > > case HWTSTAMP_FILTER_NTP_ALL:
>> > > case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
>> > > case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
>> > > case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
>> > > case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
>> > > case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
>> > > case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
>> > > case HWTSTAMP_FILTER_PTP_V2_EVENT:
>> > > case HWTSTAMP_FILTER_PTP_V2_SYNC:
>> > > case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
>> > > cfg.rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
>> > > break;
>> > > default:
>> > > mutex_unlock(&ocelot->ptp_lock);
>> > > return -ERANGE;
>> > > }
>> > >
>> > > That is essentially an upgrade to HWTSTAMP_FILTER_PTP_V2_EVENT. The
>> > > change from ALL to HWTSTAMP_FILTER_PTP_V2_EVENT is probably a simple
>> > > oversight, and the driver can be easily fixed.
>> > >
>> > > Thanks,
>> > > Richard
>> >
>> > It's essentially the same pattern as what Martin is introducing for b53.
>>
>> Uh, no it isn't. The present patch has:
>>
>> + case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
>> + case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
>> + case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
>> + case HWTSTAMP_FILTER_PTP_V2_EVENT:
>> + case HWTSTAMP_FILTER_PTP_V2_SYNC:
>> + case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
>> + case HWTSTAMP_FILTER_ALL:
>> + config->rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
>>
>> There is an important difference between
>> HWTSTAMP_FILTER_PTP_V2_L2_EVENT and HWTSTAMP_FILTER_PTP_V2_EVENT
>>
>> Notice the "L2" in there.
>
> Richard, when the request is PTP_V2_EVENT and the response is
> PTP_V2_L2_EVENT, is that an upgrade or a downgrade?

It is a downgrade, isn't it?

> PTP_V2_EVENT also includes PTP_V2_L4_EVENT.

Yes, exactly.

Thanks,
Kurt

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