Hi Richard,

-----Original Message-----
From: Richard Cochran <richardcochran@gmail.com>
Sent: Wednesday, March 25, 2020 9:42 PM
To: Y.b. Lu <yangbo.lu@nxp.com>
Cc: linux-kernel@vger.kernel.org; netdev@vger.kernel.org; David S . Miller
[off-list ref]; Vladimir Oltean [off-list ref];
Claudiu Manoil [off-list ref]; Andrew Lunn [off-list ref];
Vivien Didelot [off-list ref]; Florian Fainelli
[off-list ref]; Alexandre Belloni [off-list ref];
Microchip Linux Driver Support [off-list ref]
Subject: Re: [PATCH 6/6] ptp_ocelot: support 4 programmable pins

On Wed, Mar 25, 2020 at 03:08:46AM +0000, Y.b. Lu wrote:

quoted

The calling should be like this,
ptp_set_pinfunc (hold pincfg_mux)
---> ptp_disable_pinfunc
   ---> .enable
      ---> ptp_find_pin (hold pincfg_mux)

I see.  The call

    ptp_disable_pinfunc() --> .enable()

is really

    ptp_disable_pinfunc() --> .enable(on=0)

or disable.

All of the other drivers (except mv88e6xxx which has a bug) avoid the
deadlock by only calling ptp_find_pin() when invoked by .enable(on=1);

Of course, that is horrible, and I am going to find a way to fix it.

Thanks a lot.
Do you think it is ok to move protection into ptp_set_pinfunc() to protect just pin_config accessing?
ptp_disable_pinfunc() not touching pin_config could be out of protection.
But it seems indeed total ptp_set_pinfunc() should be under protection...

For now, maybe you can drop the "programmable pins" feature for your
driver?  After all, the pins are not programmable.

I still want to confirm, did you mean the deadlock issue? Or you thought the pin supports only PTP_PF_PEROUT in hardware?
I could modify commit messages to indicate the pin supports both PTP_PF_PEROUT and PTP_PF_EXTTS, and PTP_PF_EXTTS support will be added in the future.
Thanks a lot.

Thanks,
Richard