From patchwork Mon Jun 27 12:33:15 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King - ARM Linux X-Patchwork-Id: 920582 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p5RCa4Kf022016 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 27 Jun 2011 12:36:26 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QbB2j-0004pX-V4; Mon, 27 Jun 2011 12:35:58 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QbB2j-00060a-J8; Mon, 27 Jun 2011 12:35:57 +0000 Received: from [2002:4e20:1eda::1] (helo=caramon.arm.linux.org.uk) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QbB2g-00060I-Az for linux-arm-kernel@lists.infradead.org; Mon, 27 Jun 2011 12:35:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=caramon; h=Sender:Content-Type:MIME-Version:Message-ID:Subject:Cc:To:From:Date; bh=dICQ8icpD6Ntk17IxBjVfDiVuDo/giEln9Lc60ODjTA=; b=eJdzlYV4d0+Lyi0UDdP9YWJXya+xsIOcFEk8SU6ptqB+IiyPXnbStj5eu4YY1pAppVWZI3d4JioyXDHQC18MVgN7Sb0HDq9ny3ryX76A8ozwytezpKXUoe7C9xeBphQTRHiBCFqiN2AHqnV1qY9Y0eOKwJ7UmyfIe0PTIBu5y8Q=; Received: from n2100.arm.linux.org.uk ([2002:4e20:1eda:1:214:fdff:fe10:4f86]) by caramon.arm.linux.org.uk with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.72) (envelope-from ) id 1QbB09-0001jd-8m; Mon, 27 Jun 2011 13:33:17 +0100 Received: from linux by n2100.arm.linux.org.uk with local (Exim 4.72) (envelope-from ) id 1QbB08-0001bD-0L; Mon, 27 Jun 2011 13:33:16 +0100 Date: Mon, 27 Jun 2011 13:33:15 +0100 From: Russell King - ARM Linux To: Tony Lindgren , Kevin Hilman , Thomas Gleixner Subject: [PATCH] Use MMIO clocksource for 32kHz counter Message-ID: <20110627123315.GB1777@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.19 (2009-01-05) X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110627_083555_263236_AF4FB164 X-CRM114-Status: GOOD ( 21.29 ) X-Spam-Score: 1.2 (+) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (1.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 1.3 RDNS_NONE Delivered to internal network by a host with no rDNS Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Mon, 27 Jun 2011 12:36:26 +0000 (UTC) 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 --- While we're on the subject of OMAP timers... I guess we could convert the MMIO clocksource to use readl_relaxed() et.al. because reading the current timer register shouldn't require any barriers. Thomas? arch/arm/Kconfig | 1 + arch/arm/plat-omap/counter_32k.c | 123 +++++++++++-------------------------- 2 files changed, 38 insertions(+), 86 deletions(-) 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 f7fed60..1034bd5 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; @@ -176,18 +106,31 @@ int __init omap_init_clocksource_32k(void) "%s: can't register clocksource!\n"; if (cpu_is_omap16xx() || cpu_class_is_omap2()) { + void __iomem *base; struct clk *sync_32k_ick; - if (cpu_is_omap16xx()) - clocksource_32k.read = omap16xx_32k_read; + if (0) + base = NULL; +#ifdef CONFIG_ARCH_OMAP16XX + else if (cpu_is_omap16xx()) + base = OMAP2_L4_IO_ADDRESS(OMAP16XX_TIMER_32K_SYNCHRONIZED); +#endif +#ifdef CONFIG_SOC_OMAP2420 else if (cpu_is_omap2420()) - clocksource_32k.read = omap2420_32k_read; + base = OMAP2_L4_IO_ADDRESS(OMAP2420_32KSYNCT_BASE + 0x10); +#endif +#ifdef CONFIG_SOC_OMAP2430 else if (cpu_is_omap2430()) - clocksource_32k.read = omap2430_32k_read; + base = OMAP2_L4_IO_ADDRESS(OMAP2430_32KSYNCT_BASE + 0x10); +#endif +#ifdef CONFIG_ARCH_OMAP3 else if (cpu_is_omap34xx()) - clocksource_32k.read = omap34xx_32k_read; + base = OMAP2_L4_IO_ADDRESS(OMAP3430_32KSYNCT_BASE + 0x10); +#endif +#ifdef CONFIG_ARCH_OMAP4 else if (cpu_is_omap44xx()) - clocksource_32k.read = omap44xx_32k_read; + base = OMAP2_L4_IO_ADDRESS(OMAP4430_32KSYNCT_BASE + 0x10); +#endif else return -ENODEV; @@ -195,10 +138,18 @@ int __init omap_init_clocksource_32k(void) 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);