Hi Andrew, Harini, On 27.11.2018 07:36, Harini Katakam wrote: > Hi Claudiu, > On Mon, Nov 26, 2018 at 8:22 PM Andrew Lunn <and...@lunn.ch> wrote: >> >> On Mon, Nov 26, 2018 at 02:46:01PM +0000, claudiu.bez...@microchip.com wrote: >>> Hi Harini, >>> >>> On 26.11.2018 09:07, Harini Katakam wrote: >>>> From: Harini Katakam <hari...@xilinx.com> >>>> >>>> Replace the while loop in MDIO read/write functions with a timeout. >>>> In addition, add a check for MDIO bus busy before initiating a new >>>> operation as well to make sure there is no ongoing MDIO operation. >>> >>> Is this MDIO bus busy check necessary? The caller of >>> macb_mdio_read/macb_mdio_write locks the mdio bus mutex before calling it >>> (e.g. mdiobus_read). >> >> Hi Claudiu >> >> It depends on the implementation. A write operation you could just >> launch, but not wait for it to complete, allowing you to do other >> stuff while the hardware is busy. For the next operation you then do >> need to check the previous operation has completed. >> >> I've not checked it is actually implemented this way. > > Yes, as Andrew mentioned, a previous MDIO bus operation cannot > be assumed to be complete always - for ex., in case of a timeout. > There is a chance that the MDIO bus bit is busy when mdio_read/write > is called.
Thank you for your responses. I see it now. Then, do you think it would be better to have a new API part of struct mii_bus that drivers should register so that, the mii core to check if the bus is idle before lunching a new request? Thank you, Claudiu Beznea > > Regards, > Harini >
