From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Thu, 25 Oct 2012 15:41:25 +0100
Subject: [PATCH v5 3/5] ARM: EXYNOS: Enable PMUs for exynos4
In-Reply-To: <005801cdb251$e52f7480$af8e5d80$@samsung.com>
References: <1351056894-5790-1-git-send-email-chanho61.park@samsung.com>
 <1351056894-5790-4-git-send-email-chanho61.park@samsung.com>
 <CAOesGMg5Nn5i=J8o3Rt8es3Tq_LZgVttuYSBbvYfmw1QTGwx0A@mail.gmail.com>
 <005801cdb251$e52f7480$af8e5d80$@samsung.com>
Message-ID: <20121025144125.GH11267@mudshark.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Oct 25, 2012 at 02:41:46AM +0100, Chanho Park wrote:
> > On Tue, Oct 23, 2012 at 10:34 PM, Chanho Park
> > <chanho61.park@samsung.com> wrote:
> > > This patch defines irq numbers of ARM performance monitoring unit for
> > exynos4.
> > > Firs of all, we need to fix IRQ_PMU correctly and to split pmu
> > > initialization of exynos from plat-samsung for easily defining it.
> > >
> > > The number of CPU cores and PMU irq numbers are vary according to soc
> > types.
> > > So, we need to identify each soc type using soc_is_xxx function and to
> > > define the pmu irqs dynamically. For example, the exynos4412 has 4 cpu
> > cores and pmus.
> > 
> > I wonder if it's worth doing this complexity on the non-DT case for exynos4?
> > 
> > I wish there was more focus on the Samsung platforms for getting the DT
> > support up to par with non-DT so you can avoid having to add new platform
> > devices like these in the first place.
> 
> The DT support of exynos4 is under development.

It seems to have been under development for a while now and changes like
this don't exactly encourage people to chip-in with that effort. Would it
not be better to spend time helping to complete the DT support instead of
retro-fitting static platform devices into the code?

> And many of exynos4 developers still use non-dt boot-up method.

That's not surprising if the DT code is still under development -- it's a
chicken-and-egg problem.

> By this time arm-pmu of exynos did not work. IMO we should fix and support it
> for non-dt users.

I agree that we definitely want to support the PMU on Exynos4, but I'm
tempted to postpone adding that code until DT support is available.

Will