netdev - Re: [PATCH net-next] drivers: net: davinci

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Message-ID: <a0ede4ae-a489-4eb6-83d3-0e22541de2b3@ti.com>
Date:   Wed, 9 May 2018 16:14:42 +0530
From:   Sekhar Nori <nsekhar@...com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     Grygorii Strashko <grygorii.strashko@...com>,
        "David S . Miller" <davem@...emloft.net>,
        <linux-omap@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] drivers: net: davinci_mdio: prevent sprious
 timeout

On Tuesday 08 May 2018 06:18 PM, Andrew Lunn wrote:
> On Tue, May 08, 2018 at 01:56:38PM +0530, Sekhar Nori wrote:
>> A well timed kernel preemption in the time_after() loop
>> in wait_for_idle() can result in a spurious timeout
>> error to be returned.
>>
>> Fix it by checking for status of hardware before returning
>> timeout error.
>>
>> Signed-off-by: Sekhar Nori <nsekhar@...com>
> 
> I've seen this with other drivers as well.
> 
> I suggest you make use of readx_poll_timeout(), or one of its
> cousins. They get this right.

Thanks for pointing me to these. I somehow thought these helpers are
only available with regmap.

Sending a version using readl_poll_timeout(). I know __raw_readl() is
used elsewhere in the driver, but I think that should be cleaned up
sometime to use readl_relaxed() at least. So not sure if there is
benefit in persisting with existing accessor.

Thanks,
Sekhar