netdev - Re: [PATCH v3 net-next 5/8] net: dsa: felix: support psfp filter on vsc9959

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Message-ID: <20210831085510.7hjweoagnmwde6aq@skbuf>
Date:   Tue, 31 Aug 2021 08:55:11 +0000
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     Xiaoliang Yang <xiaoliang.yang_1@....com>
CC:     "davem@...emloft.net" <davem@...emloft.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "allan.nielsen@...rochip.com" <allan.nielsen@...rochip.com>,
        "joergen.andreasen@...rochip.com" <joergen.andreasen@...rochip.com>,
        "UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
        "vinicius.gomes@...el.com" <vinicius.gomes@...el.com>,
        "michael.chan@...adcom.com" <michael.chan@...adcom.com>,
        "saeedm@...lanox.com" <saeedm@...lanox.com>,
        "jiri@...lanox.com" <jiri@...lanox.com>,
        "idosch@...lanox.com" <idosch@...lanox.com>,
        "alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
        "kuba@...nel.org" <kuba@...nel.org>, Po Liu <po.liu@....com>,
        Leo Li <leoyang.li@....com>
Subject: Re: [PATCH v3 net-next 5/8] net: dsa: felix: support psfp filter on
 vsc9959

On Tue, Aug 31, 2021 at 11:46:10AM +0300, Vladimir Oltean wrote:
> On Tue, Aug 31, 2021 at 08:41:36AM +0000, Xiaoliang Yang wrote:
> > Hi Vladimir,
> >
> > On Tue, Aug 31, 2021 at 15:55:26AM +0800, Vladimir Oltean wrote:
> > > > +static int vsc9959_mact_stream_set(struct ocelot *ocelot,
> > > > +				   struct felix_stream *stream,
> > > > +				   struct netlink_ext_ack *extack) {
> > > > +	struct ocelot_mact_entry entry;
> > > > +	u32 row, col, reg, dst_idx;
> > > > +	int ret;
> > > > +
> > > > +	/* Stream identification desn't support to add a stream with non
> > > > +	 * existent MAC (The MAC entry has not been learned in MAC table).
> > > > +	 */
> > >
> > > Who will add the MAC entry to the MAC table in this design? The user?
> >
> > Yes, The MAC entry is always learned by hardware, user also can add it
> > by using "bridge fdb add".
> >
> > > So if the STREAMDATA entry for this SFID was valid, you mark the MAC table
> > > entry as static, otherwise you mark it as ageable? Why?
> >
> > If the MAC entry is learned by hardware, it's marked as ageable. When
> > setting the PSFP filter on this stream, it needs to be set to static.
> > For example, if the MAC table entry is not set to static, when link is
> > down for a period of time, the MAC entry will be forgotten, and SFID
> > information will be lost.
> > After disable PSFP filter on the stream, there is no need to keep the
> > MAC entry static, setting the type back to ageable can cope with
> > network topology changes.
> >
> 
> So if the MAC table entry is ageable, will the TSN stream disappear from
> hardware even though it is still present in tc?

Ah, ok, I was missing the context of the larger change.
vsc9959_psfp_filter_del sets stream->sfid_valid = 0, then calls
vsc9959_stream_table_del which calls the common vsc9959_mact_stream_set.

> I think in previous versions you were automatically installing a static
> MAC table entry when one was not present (either it was absent, or the
> entry was dynamically learned). Why did that change?

This question remains though.