From: Boris Brezillon <boris.brezillon@collabora.com> To: Vitor Soares <Vitor.Soares@synopsys.com> Cc: Przemyslaw Gaj <pgaj@cadence.com>, "linux-i3c@lists.infradead.org" <linux-i3c@lists.infradead.org>, "bbrezillon@kernel.org" <bbrezillon@kernel.org> Subject: Re: I3C Mastership RFC Date: Mon, 25 Nov 2019 14:09:36 +0100 Message-ID: <20191125140936.47f3d479@collabora.com> (raw) In-Reply-To: <CH2PR12MB421644B0CAB1DEF50675995EAE4A0@CH2PR12MB4216.namprd12.prod.outlook.com> On Mon, 25 Nov 2019 13:00:17 +0000 Vitor Soares <Vitor.Soares@synopsys.com> wrote: > > > > > > I'm pretty sure we solved that already (that's what > > > > > > i3c_master_acquire_bus_ownership() calls are supposed to take care of). > > > > > > Can you be a bit more specific? What makes you think the master might > > > > > > not be in control of the bus when i3c_dev_do_priv_xfers_locked() is > > > > > > called? > > > > > > > > > > You are assuming that after i3c_master_acquire_bus_ownership() return, > > > > > secondary master already owns the bus. Main master can ack the MR request > > > > > and not send the CETACCMST immediately. > > > > > > > > > > > > > In Cadence HC driver, I'm waiting for GETACCMST longer, polling the > > > > status and after I exit from ->request_mastership(), I'm the bus owner. > > > > If not, error exit code is returned and we can't make the transfers. > > > > Are you able to implement the same behavior? > > > > > > You can assume everyone will do in that way. What happen if you receive a > > > request or an information from current master? > > > > We have this ->request_mastership() method so controllers that have > > this logic (MR+wait(GETACCMST) automated can still interface with the > > subsystem. > > I can also poll the GETACCMST but we are assuming nothing will happen > between MR and GETACCMST. Nothing coming from the master that tries to acquire the bus, yes. Nothing coming from the current master, no, and that shouldn't be a problem as long as those operations don't involve acquiring bus->lock. And if some of those operation involve acquiring the lock (I'd still need to understand which operation that would be) they'll just be delayed/rejected. > > > If your controller handles the MR/GETACCMST separately, it > > shouldn't be hard to implement, and we can even provide an helper if > > people end up duplicating the code. > > I already implement a callback in my code so each controller be able to > do their stuff in that in request/deliver mastership. Can you share some details here? What would those callbacks supposed to do and when would they be called? _______________________________________________ linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c
next prev parent reply index Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-06 9:33 Przemyslaw Gaj 2019-11-10 10:30 ` Boris Brezillon 2019-11-11 12:30 ` Vitor Soares 2019-11-12 7:41 ` Boris Brezillon 2019-11-14 6:10 ` Przemyslaw Gaj 2019-11-14 11:56 ` Vitor Soares 2019-11-14 12:32 ` Boris Brezillon 2019-11-14 12:59 ` Przemyslaw Gaj 2019-11-14 14:17 ` Vitor Soares 2019-11-14 14:50 ` Boris Brezillon 2019-11-14 20:15 ` Przemyslaw Gaj 2019-11-25 8:02 ` Przemyslaw Gaj 2019-11-25 11:19 ` Vitor Soares 2019-11-25 11:34 ` Boris Brezillon 2019-11-25 11:42 ` Vitor Soares 2019-11-25 11:55 ` Przemyslaw Gaj 2019-11-25 12:03 ` Vitor Soares 2019-11-25 12:22 ` Boris Brezillon 2019-11-25 13:00 ` Vitor Soares 2019-11-25 13:09 ` Boris Brezillon [this message] 2019-11-25 14:27 ` Vitor Soares 2019-11-25 14:50 ` Boris Brezillon 2019-11-25 14:59 ` Przemyslaw Gaj 2019-11-25 15:22 ` Vitor Soares 2019-11-25 12:25 ` Przemyslaw Gaj 2019-11-25 12:56 ` Vitor Soares 2019-11-25 11:50 ` Przemyslaw Gaj
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