From patchwork Mon Jul 11 06:17:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 963392 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p6B6HgX4027474 for ; Mon, 11 Jul 2011 06:17:42 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757093Ab1GKGRl (ORCPT ); Mon, 11 Jul 2011 02:17:41 -0400 Received: from mho-03-ewr.mailhop.org ([204.13.248.66]:30700 "EHLO mho-01-ewr.mailhop.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756726Ab1GKGRl (ORCPT ); Mon, 11 Jul 2011 02:17:41 -0400 Received: from c-98-234-237-12.hsd1.ca.comcast.net ([98.234.237.12] helo=localhost.localdomain) by mho-01-ewr.mailhop.org with esmtpa (Exim 4.72) (envelope-from ) id 1Qg9oE-000D9W-HV; Mon, 11 Jul 2011 06:17:34 +0000 Received: from Mutt by mutt-smtp-wrapper.pl 1.2 (www.zdo.com/articles/mutt-smtp-wrapper.shtml) X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 98.234.237.12 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX18RHat9BxiLByQI/vqaJn7x Date: Sun, 10 Jul 2011 23:17:31 -0700 From: Tony Lindgren To: Russell King - ARM Linux Cc: Kevin Hilman , Thomas Gleixner , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] Use MMIO clocksource for 32kHz counter Message-ID: <20110711061731.GM5783@atomide.com> References: <20110627123315.GB1777@n2100.arm.linux.org.uk> <20110627123754.GQ23145@atomide.com> <20110627191102.GV23145@atomide.com> <20110710141537.GB4957@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110710141537.GB4957@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 11 Jul 2011 06:17:43 +0000 (UTC) * Russell King - ARM Linux [110710 07:10]: > On Mon, Jun 27, 2011 at 12:11:02PM -0700, Tony Lindgren wrote: > > * Tony Lindgren [110627 05:33]: > > > * Russell King - ARM Linux [110627 05:28]: > > > > --- a/arch/arm/plat-omap/counter_32k.c > > > > +++ b/arch/arm/plat-omap/counter_32k.c > > > > +#ifdef CONFIG_ARCH_OMAP16XX > > > > + else if (cpu_is_omap16xx()) > > > > + base = OMAP2_L4_IO_ADDRESS(OMAP16XX_TIMER_32K_SYNCHRONIZED); > > > > BTW, the above should have been OMAP1_IO_ADDRESS instead.. > > > > > You should be able to replace the above with just ioremap as we now > > > have the static mappings. > > > > ..here's a patch to use ioremap with comment added about the static > > mapping requirements. > > > > Thanks for getting rid of hopefully the last remaining omap_readl > > for omap2+ BTW :) > > What're we doing with this patch and your follow-up patch? I can queue it, it does not seem to conflict with other patches. Below is the combined version. Regards, Tony From: Russell King - ARM Linux Date: Sun, 10 Jul 2011 23:05:34 -0700 Subject: [PATCH] Convert OMAPs 32kHz clocksource implementation to use the generic MMIO clocksource support. This achieves several things: 1. It means we get rid of all these helper functions which frankly should never have been necessary. 2. It means omap_readl() inside these helper functions does not appear in ftrace output. Another plus is that we avoid the overhead of calculating the address to read each time, but a minus is that we use readl() which has a barrier. Signed-off-by: Russell King [tony@atomide.com: updated to use ioremap] Signed-off-by: Tony Lindgren --- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 9adc278..c1795c9 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -852,6 +852,7 @@ config ARCH_OMAP select HAVE_CLK select ARCH_REQUIRE_GPIOLIB select ARCH_HAS_CPUFREQ + select CLKSRC_MMIO select GENERIC_CLOCKEVENTS select HAVE_SCHED_CLOCK select ARCH_HAS_HOLES_MEMORYMODEL diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c index c13bc3d..a6cbb71 100644 --- a/arch/arm/plat-omap/counter_32k.c +++ b/arch/arm/plat-omap/counter_32k.c @@ -18,6 +18,7 @@ #include #include #include +#include #include @@ -26,87 +27,16 @@ #include - /* * 32KHz clocksource ... always available, on pretty most chips except * OMAP 730 and 1510. Other timers could be used as clocksources, with * higher resolution in free-running counter modes (e.g. 12 MHz xtal), * but systems won't necessarily want to spend resources that way. */ +static void __iomem *timer_32k_base; #define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410 -#include - -/* - * offset_32k holds the init time counter value. It is then subtracted - * from every counter read to achieve a counter that counts time from the - * kernel boot (needed for sched_clock()). - */ -static u32 offset_32k __read_mostly; - -#ifdef CONFIG_ARCH_OMAP16XX -static cycle_t notrace omap16xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED) - offset_32k; -} -#else -#define omap16xx_32k_read NULL -#endif - -#ifdef CONFIG_SOC_OMAP2420 -static cycle_t notrace omap2420_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap2420_32k_read NULL -#endif - -#ifdef CONFIG_SOC_OMAP2430 -static cycle_t notrace omap2430_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap2430_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP3 -static cycle_t notrace omap34xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap34xx_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP4 -static cycle_t notrace omap44xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap44xx_32k_read NULL -#endif - -/* - * Kernel assumes that sched_clock can be called early but may not have - * things ready yet. - */ -static cycle_t notrace omap_32k_read_dummy(struct clocksource *cs) -{ - return 0; -} - -static struct clocksource clocksource_32k = { - .name = "32k_counter", - .rating = 250, - .read = omap_32k_read_dummy, - .mask = CLOCKSOURCE_MASK(32), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - /* * Returns current time from boot in nsecs. It's OK for this to wrap * around for now, as it's just a relative time stamp. @@ -122,7 +52,7 @@ static DEFINE_CLOCK_DATA(cd); static inline unsigned long long notrace _omap_32k_sched_clock(void) { - u32 cyc = clocksource_32k.read(&clocksource_32k); + u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0; return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT); } @@ -140,7 +70,7 @@ unsigned long long notrace omap_32k_sched_clock(void) static void notrace omap_update_sched_clock(void) { - u32 cyc = clocksource_32k.read(&clocksource_32k); + u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0; update_sched_clock(&cd, cyc, (u32)~0); } @@ -153,6 +83,7 @@ static void notrace omap_update_sched_clock(void) */ static struct timespec persistent_ts; static cycles_t cycles, last_cycles; +static unsigned int persistent_mult, persistent_shift; void read_persistent_clock(struct timespec *ts) { unsigned long long nsecs; @@ -160,11 +91,10 @@ void read_persistent_clock(struct timespec *ts) struct timespec *tsp = &persistent_ts; last_cycles = cycles; - cycles = clocksource_32k.read(&clocksource_32k); + cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0; delta = cycles - last_cycles; - nsecs = clocksource_cyc2ns(delta, - clocksource_32k.mult, clocksource_32k.shift); + nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift); timespec_add_ns(tsp, nsecs); *ts = *tsp; @@ -176,29 +106,46 @@ int __init omap_init_clocksource_32k(void) "%s: can't register clocksource!\n"; if (cpu_is_omap16xx() || cpu_class_is_omap2()) { + u32 pbase; + unsigned long size = SZ_4K; + void __iomem *base; struct clk *sync_32k_ick; - if (cpu_is_omap16xx()) - clocksource_32k.read = omap16xx_32k_read; - else if (cpu_is_omap2420()) - clocksource_32k.read = omap2420_32k_read; + if (cpu_is_omap16xx()) { + pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED; + size = SZ_1K; + } else if (cpu_is_omap2420()) + pbase = OMAP2420_32KSYNCT_BASE + 0x10; else if (cpu_is_omap2430()) - clocksource_32k.read = omap2430_32k_read; + pbase = OMAP2430_32KSYNCT_BASE + 0x10; else if (cpu_is_omap34xx()) - clocksource_32k.read = omap34xx_32k_read; + pbase = OMAP3430_32KSYNCT_BASE + 0x10; else if (cpu_is_omap44xx()) - clocksource_32k.read = omap44xx_32k_read; + pbase = OMAP4430_32KSYNCT_BASE + 0x10; else return -ENODEV; + /* For this to work we must have a static mapping in io.c for this area */ + base = ioremap(pbase, size); + if (!base) + return -ENODEV; + sync_32k_ick = clk_get(NULL, "omap_32ksync_ick"); if (!IS_ERR(sync_32k_ick)) clk_enable(sync_32k_ick); - offset_32k = clocksource_32k.read(&clocksource_32k); + timer_32k_base = base; + + /* + * 120000 rough estimate from the calculations in + * __clocksource_updatefreq_scale. + */ + clocks_calc_mult_shift(&persistent_mult, &persistent_shift, + 32768, NSEC_PER_SEC, 120000); - if (clocksource_register_hz(&clocksource_32k, 32768)) - printk(err, clocksource_32k.name); + if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32, + clocksource_mmio_readl_up)) + printk(err, "32k_counter"); init_fixed_sched_clock(&cd, omap_update_sched_clock, 32, 32768, SC_MULT, SC_SHIFT);