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Date: Thu, 20 Jun 2013 16:44:33 +0200 From: Pavel Machek <pavel@...x.de> To: Baruch Siach <baruch@...s.co.il> Cc: John Stultz <john.stultz@...aro.org>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, Jamie Iles <jamie@...ieiles.com>, Dinh Nguyen <dinguyen@...era.com> Subject: Re: [RFC PATCH 2/2] clocksource: dw_apb: allow build for architectures other than arm Hi! > > >@@ -73,6 +77,9 @@ static void add_clocksource(struct device_node > > > *source_timer) > > > } > > > static void __iomem *sched_io_base; > > >+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK > > >+static u64 sched_clock_mult __read_mostly; > > >+#endif > > > static u32 read_sched_clock(void) > > > { > > >@@ -97,7 +104,11 @@ static void init_sched_clock(void) > > > timer_get_base_and_rate(sched_timer, &sched_io_base, &rate); > > > of_node_put(sched_timer); > > >+#ifdef CONFIG_HAVE_SETUP_SCHED_CLOCK > > > setup_sched_clock(read_sched_clock, 32, rate); > > >+#else > > >+ sched_clock_mult = NSEC_PER_SEC / rate; > > >+#endif > > > } > > > > Can you rework this to not use #ifdefs within the function? They > > make it annoying to read the code. > > > > Instead maybe have a local setup_sched_clock() function that sets > > the mult value for the !CONFIG_HAVE_SETUP_SCHED_CLOCK case? > > > > > static const struct of_device_id osctimer_ids[] __initconst = { > > >@@ -124,3 +135,10 @@ void __init dw_apb_timer_init(void) > > > init_sched_clock(); > > > } > > >+ > > >+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK > > >+unsigned long long notrace sched_clock() > > >+{ > > >+ return read_sched_clock() * sched_clock_mult; > > >+} > > >+#endif > > > > Also, can you try to condense the number of #ifndef > > CONFIG_HAVE_SETUP_SCHED_CLOCK checks to one, and consolidate the > > needed functions all in that one conditional? > > Thanks for your comments. I'll rework the patch and resubmit. > > I've just noticed that I have a bigger problem. read_sched_clock() returns > u32, not u64. This means that in a rate of, say, 100MHz it will wrap around > after a little more than 40 seconds. Would it make sense to put ARM's 32 bin > sched_clock extension code (arch/arm/kernel/sched_clock.c) is a common place > (maybe drivers/clocksource), and use that? There seems to be nothing ARM > specific in this code, after all. Also note that there are two conflicting changes to this area pending. It seems one in soc-next arm tree will prevail. Please take a look... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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