linux-mips
[Top] [All Lists]

Re: [PATCH -v6 02/13] tracing: add mips_timecounter_read() for MIPS

To: linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH -v6 02/13] tracing: add mips_timecounter_read() for MIPS
From: Wu Zhangjin <wuzhangjin@gmail.com>
Date: Mon, 09 Nov 2009 12:15:16 +0800
Cc: linux-kernel@vger.kernel.org, Frederic Weisbecker <fweisbec@gmail.com>, rostedt@goodmis.org, Thomas Gleixner <tglx@linutronix.de>, Ralf Baechle <ralf@linux-mips.org>, Richard Sandiford <rdsandiford@googlemail.com>, Nicholas Mc Guire <der.herr@hofr.at>, David Daney <ddaney@caviumnetworks.com>, Adam Nemet <anemet@caviumnetworks.com>, Patrik Kluba <kpajko79@gmail.com>
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:subject:from:reply-to:to:cc :in-reply-to:references:content-type:organization:date:message-id :mime-version:x-mailer:content-transfer-encoding; bh=ei7clv15wKKuydOKUSU0J2boP4ac4j8VxgvzOlfLMAY=; b=FWW3mhPRbgu0Vz0oE7MNOtC9ON7NiQCm+RNisBp93LXvEVw1XFjn351S36iiBYFYfk VlSF0xKi+D9O7yVuxzcSr/6J0v6SRVcYMmjZKdn9zLds8GBC9bwSk+FfTEcdOhvKveai 6sqw6IA0+DdgmvMywk9+CG0EGEyo4xnRV+18U=
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=
In-reply-to: <3f47087b70a965fd679b17a59521671296457df1.1256569489.git.wuzhangjin@gmail.com>
Organization: DSLab, Lanzhou University, China
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <cover.1256569489.git.wuzhangjin@gmail.com> <747deea2f18d5ccffe842df95a9dd1c86251a958.1256569489.git.wuzhangjin@gmail.com> <3f47087b70a965fd679b17a59521671296457df1.1256569489.git.wuzhangjin@gmail.com>
Reply-to: wuzhangjin@gmail.com
Sender: linux-mips-bounce@linux-mips.org
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 <wuzhangjin@gmail.com>
> ---
>  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 <linux/clocksource.h>
>  #include <linux/init.h>
> +#include <linux/sched.h>
>  
>  #include <asm/time.h>
>  
> @@ -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();
>  }



<Prev in Thread] Current Thread [Next in Thread>
  • Re: [PATCH -v6 02/13] tracing: add mips_timecounter_read() for MIPS, Wu Zhangjin <=