On 05/24/2017 04:36 PM, Florian Fainelli wrote:
OK, and there is no way you can run into the following race condition:
CPU HW
MDIO read intent
polling starts
disable HW autopoll
polling continues
Disabling of the HW autopoll waits for the poll to actually stop before
continuing. You can see the code here:
http://elixir.free-electrons.com/linux/latest/source/drivers/net/ethernet/qualcomm/emac/emac-phy.c#L102
MDIO read is done
MDIO read done
polling stops
MDIO read value returned
if you disable autopolling in HW this is guaranteed to immediately stop
by the time the register value is seen in HW and your I/O read/write
returns?
It doesn't immediately stop, but the emac_phy_mdio_autopoll_disable()
function waits for the MDIO bus to not be busy. But low-level details
of this feature are not documented, so who knows what it does exactly?
The original code that used this feature only supported one PHY and
never expected there to be any asynchronous MDIO transactios.
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