On 02/19/2017 10:26 PM, YUAN Linyu wrote: > > >> -----Original Message----- >> From: Florian Fainelli [mailto:f.faine...@gmail.com] >> Sent: Monday, February 20, 2017 2:16 PM >> To: YUAN Linyu; David S . Miller; Andrew Lunn >> Cc: netdev@vger.kernel.org; cug...@163.com >> Subject: Re: create drivers/net/mdio and move mdio drivers into it >> >> >> >> On 02/19/2017 10:10 PM, YUAN Linyu wrote: >>> >>> >>>> -----Original Message----- >>>> From: Florian Fainelli [mailto:f.faine...@gmail.com] >>>> Sent: Monday, February 20, 2017 1:42 PM >>>> To: YUAN Linyu; David S . Miller; Andrew Lunn >>>> Cc: netdev@vger.kernel.org; cug...@163.com >>>> Subject: Re: create drivers/net/mdio and move mdio drivers into it >>>>> 3. another idea is bind mdio device to network device >>>> >>>> You would have to be more specific about what you want to do here. If >>>> the MDIO device is e.g: a switch, what we recommend doing is provide a >>>> fixed-link node that describes how the Ethernet MAC and the switch's >>>> CPU/management ports are connected (that way the MAC always "sees" >> the >>>> link as UP, running with a specific speed and duplex). >>>> >>> Yes, some system will configured the phy to fixed speed/duplex at boot time, >>> no phy driver used in kernel at all. >> >> There is always a PHY driver used, either is a dedicated one, or its the >> generic PHY driver in drivers/net/phy/phy_device.c, even when fixed >> PHYs/link are used. >> >>> If network device know mdio device it used, we can do phy dump through this >>> mdio device driver. >> >> We are not going to accept MDIO device drivers whose only purpose is to >> allow PHY devices register dumps. Implement a proper PHY driver for >> these devices, if nothing needs to be done, you just need to call into >> genphy_* functions, and just override how to do register dumps. >> > No, we discuss mdio driver here, not phy driver. > I mean if a network device know mdio device it used, we use mdio driver to > dump any register of phy device even it's driver is not build.
The network device is supposed to attach to a PHY, which in turns has a backing PHY driver, which is a superset of a MDIO device driver. If the thing you are after is to be able to do PHY device register dumps without a PHY driver to assist you with that, then we need to add whole lot of things: - have an ioctl() which allows stopping/freezing the PHY state machine so dumps don't interfere with the PHY state - have the ability to reliably perform PHY dumps that e.g: require page programming etc. etc. Then again, all of this could be done by a PHY driver reliably and in a way that is consistent and predictable. -- Florian
