> >> DW EQoS v5.xx controllers added capability for interrupt generation > >> when MDIO interface is done (GMII Busy bit is cleared). > >> This patch adds support for this interrupt on supported HW to avoid > >> polling on GMII Busy bit. > >> > >> stmmac_mdio_read() & stmmac_mdio_write() will sleep until wake_up() > >> is called by the interrupt handler. > > > > Hi Voon > > > > I _think_ there are some order of operation issues here. The mdiobus > > is registered in the probe function. As soon as of_mdiobus_register() > > is called, the MDIO bus must work. At that point MDIO read/writes can > > start to happen. > > > > As far as i can see, the interrupt handler is only requested in > > stmmac_open(). So it seems like any MDIO operations after probe, but > > before open are going to fail? > > AFAIR, wait_event_timeout() will continue to busy loop and wait until > the timeout, but not return an error because the polled condition was > true, at least that is my recollection from having the same issue with > the bcmgenet driver before it was moved to connecting to the PHY in the > ndo_open() function. > -- > Florian
Florian is right as the poll condition is still true after the timeout. Hence, any mdio operation after probe and before ndo_open will still work. The only cons here is that attaching the PHY will takes a full length of timeout time for each mdio_read and mdio_write. So we should attach the phy only after the interrupt handler is requested?
