Messages in this thread | | | From | Andy Duan <> | Subject | RE: [EXT] Re: [PATCH net-next 0/1] net: fec: add C45 MDIO read/write support | Date | Wed, 21 Aug 2019 05:55:56 +0000 |
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From: Andrew Lunn <andrew@lunn.ch> Sent: Tuesday, August 20, 2019 9:04 PM > On Tue, Aug 20, 2019 at 02:32:26AM +0000, Andy Duan wrote: > > From: Andrew Lunn <andrew@lunn.ch> > > > On Mon, Aug 19, 2019 at 05:11:14PM +0000, Marco Hartmann wrote: > > > > As of yet, the Fast Ethernet Controller (FEC) driver only supports > > > > Clause 22 conform MDIO transactions. IEEE 802.3ae Clause 45 > > > > defines a modified MDIO protocol that uses a two staged access > > > > model in order to increase the address space. > > > > > > > > This patch adds support for Clause 45 conform MDIO read and write > > > > operations to the FEC driver. > > > > > > Hi Marco > > > > > > Do all versions of the FEC hardware support C45? Or do we need to > > > make use of the quirk support in this driver to just enable it for some > revisions of FEC? > > > > > > Thanks > > > Andrew > > > > i.MX legacy platforms like i.MX6/7 series, they doesn't support Write & Read > Increment. > > But for i.MX8MQ/MM series, it support C45 full features like Write & Read > Increment. > > > > For the patch itself, it doesn't support Write & Read Increment, so I > > think the patch doesn't need to add quirk support. > > Hi Andy > > So what happens with something older than a i.MX8MQ/MM when a C45 > transfer is attempted? This patch adds a new write. Does that write > immediately trigger a completion interrupt? Does it never trigger an interrupt, > and we have to wait FEC_MII_TIMEOUT? > > Ideally, if the hardware does not support C45, we want it to return > EOPNOTSUPP. > > Thanks > Andrew
It still trigger an interrupt to wakeup the completion, we have to wait FEC_MII_TIMEOUT. Older chips just support part of C45 feature just like the patch implementation.
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