Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753681AbZKIEPU (ORCPT ); Sun, 8 Nov 2009 23:15:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752562AbZKIEPT (ORCPT ); Sun, 8 Nov 2009 23:15:19 -0500 Received: from mail-px0-f204.google.com ([209.85.216.204]:59044 "EHLO mail-px0-f204.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751092AbZKIEPR (ORCPT ); Sun, 8 Nov 2009 23:15:17 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:reply-to:to:cc:in-reply-to:references:content-type :organization:date:message-id:mime-version:x-mailer :content-transfer-encoding; b=F4vAqXDDleGbCUAN57l53NWJojEAosNwNkxPcN6BtiwW+CfGmwplpLS7Z79+SoZcHD +nHE9SBFvWnPaC9stNi/Wm+lb7xzK8DEIxiJV+rc1ZtogIOFDxuCD6kbsKwmrZ+Dc9FZ JCUCZF6zE9Dnd1n3dc/W13XdTlgExYD2x+7vY= Subject: Re: [PATCH -v6 02/13] tracing: add mips_timecounter_read() for MIPS From: Wu Zhangjin Reply-To: wuzhangjin@gmail.com To: linux-mips@linux-mips.org, Ralf Baechle Cc: linux-kernel@vger.kernel.org, Frederic Weisbecker , rostedt@goodmis.org, Thomas Gleixner , Ralf Baechle , Richard Sandiford , Nicholas Mc Guire , David Daney , Adam Nemet , Patrik Kluba In-Reply-To: <3f47087b70a965fd679b17a59521671296457df1.1256569489.git.wuzhangjin@gmail.com> References: <747deea2f18d5ccffe842df95a9dd1c86251a958.1256569489.git.wuzhangjin@gmail.com> <3f47087b70a965fd679b17a59521671296457df1.1256569489.git.wuzhangjin@gmail.com> Content-Type: text/plain; charset="UTF-8" Organization: DSLab, Lanzhou University, China Date: Mon, 09 Nov 2009 12:15:16 +0800 Message-ID: <1257740116.3451.14.camel@falcon.domain.org> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3644 Lines: 137 Hi Ralf, Could you please give some feedback on this patch? Really looking forward to your feedback and then resend this patchset out ;) Thanks & Regards, Wu Zhangjin On Mon, 2009-10-26 at 23:13 +0800, Wu Zhangjin wrote: > This patch add a new function: mips_timecounter_read() to get high > precision timestamp without extra lock. > > It is based on the clock counter register and the > timecounter/cyclecounter abstraction layer of kernel. > > Signed-off-by: Wu Zhangjin > --- > arch/mips/include/asm/time.h | 19 +++++++++++++++++++ > arch/mips/kernel/csrc-r4k.c | 41 +++++++++++++++++++++++++++++++++++++++++ > arch/mips/kernel/time.c | 2 ++ > 3 files changed, 62 insertions(+), 0 deletions(-) > > diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h > index df6a430..b8af7fa 100644 > --- a/arch/mips/include/asm/time.h > +++ b/arch/mips/include/asm/time.h > @@ -73,8 +73,18 @@ static inline int mips_clockevent_init(void) > */ > #ifdef CONFIG_CSRC_R4K_LIB > extern int init_r4k_clocksource(void); > +extern int init_r4k_timecounter(void); > +extern u64 r4k_timecounter_read(void); > #endif > > +static inline u64 mips_timecounter_read(void) > +{ > +#ifdef CONFIG_CSRC_R4K > + return r4k_timecounter_read(); > +#else > + return sched_clock(); > +#endif > +} > static inline int init_mips_clocksource(void) > { > #ifdef CONFIG_CSRC_R4K > @@ -84,6 +94,15 @@ static inline int init_mips_clocksource(void) > #endif > } > > +static inline int init_mips_timecounter(void) > +{ > +#ifdef CONFIG_CSRC_R4K > + return init_r4k_timecounter(); > +#else > + return 0; > +#endif > +} > + > extern void clocksource_set_clock(struct clocksource *cs, unsigned int clock); > extern void clockevent_set_clock(struct clock_event_device *cd, > unsigned int clock); > diff --git a/arch/mips/kernel/csrc-r4k.c b/arch/mips/kernel/csrc-r4k.c > index e95a3cd..4e7705f 100644 > --- a/arch/mips/kernel/csrc-r4k.c > +++ b/arch/mips/kernel/csrc-r4k.c > @@ -7,6 +7,7 @@ > */ > #include > #include > +#include > > #include > > @@ -36,3 +37,43 @@ int __init init_r4k_clocksource(void) > > return 0; > } > + > +static struct timecounter r4k_tc = { > + .cc = NULL, > +}; > + > +static cycle_t r4k_cc_read(const struct cyclecounter *cc) > +{ > + return read_c0_count(); > +} > + > +static struct cyclecounter r4k_cc = { > + .read = r4k_cc_read, > + .mask = CLOCKSOURCE_MASK(32), > + .shift = 32, > +}; > + > +int __init init_r4k_timecounter(void) > +{ > + if (!cpu_has_counter || !mips_hpt_frequency) > + return -ENXIO; > + > + r4k_cc.mult = div_sc((unsigned long)mips_hpt_frequency, NSEC_PER_SEC, > + 32); > + > + timecounter_init(&r4k_tc, &r4k_cc, sched_clock()); > + > + return 0; > +} > + > +u64 r4k_timecounter_read(void) > +{ > + u64 clock; > + > + if (r4k_tc.cc != NULL) > + clock = timecounter_read(&r4k_tc); > + else > + clock = sched_clock(); > + > + return clock; > +} > diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c > index 1f467d5..e38cca1 100644 > --- a/arch/mips/kernel/time.c > +++ b/arch/mips/kernel/time.c > @@ -156,4 +156,6 @@ void __init time_init(void) > > if (!mips_clockevent_init() || !cpu_has_mfc0_count_bug()) > init_mips_clocksource(); > + if (!cpu_has_mfc0_count_bug()) > + init_mips_timecounter(); > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/