Re: [PATCH v5 1/3] clocksource: timer-keystone: introduce clocksourcedriver for Keystone

[Ivan Khoronzhuk]

On 02/05/2014 10:27 PM, Thomas Gleixner wrote:
> On Wed, 5 Feb 2014, Ivan Khoronzhuk wrote:
> > +	/* here we have to be sure the timer has been disabled */
> Sigh. This is not a proper explanation for a barrier, really. You want
> to explain what it serializes against what. i.e. you want to explain
> why you are using the relaxed functions and avoid a separate non
> relaxed variant in favour of an explicit barrier.
>
> > +	__iowmb();
> The proper thing is to have an inline function key_stone_barrier() and
> a full explanation of the issue in exactly that place instead of
> handwaving comments here and there.
>
> Thanks,
>
> 	tglx

I can add new inline function like:

/**
 * keystone_timer_barrier: write memory barrier
 * use explicit barrier to avoid using readl/writel non relaxed function
 * variants, because in our case relaxed variants hide the true places
 * where barrier is needed.
 */
static inline void keystone_timer_barrier(void)
{
    __iowmb();
}

and use it where it is needed.
Are you OK with it?

And I propose to leave comments under the barriers in order to be
able to understand why they are used.

--
Regards,
Ivan Khoronzhuk

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