From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756922AbZCCQRy (ORCPT ); Tue, 3 Mar 2009 11:17:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756866AbZCCQRX (ORCPT ); Tue, 3 Mar 2009 11:17:23 -0500 Received: from mx1.emlix.com ([193.175.82.87]:35430 "EHLO mx1.emlix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756666AbZCCQRV (ORCPT ); Tue, 3 Mar 2009 11:17:21 -0500 References: User-Agent: quilt/0.46-1 Date: Tue, 03 Mar 2009 16:30:46 +0100 From: Johannes Weiner To: Chris Zankel Cc: linux-kernel@vger.kernel.org, Johannes Weiner Subject: [patch 3/3] xtensa: ccount clocksource Content-Disposition: inline; filename=xtensa-ccount-clocksource.patch Message-Id: Organization: emlix gmbh, Goettingen, Germany Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Weiner Switch to GENERIC_TIME by using the ccount register as a clock source. Signed-off-by: Johannes Weiner --- arch/xtensa/Kconfig | 3 + arch/xtensa/kernel/time.c | 92 ++++++++++------------------------------------ 2 files changed, 23 insertions(+), 72 deletions(-) --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -45,6 +45,9 @@ config HZ int default 100 +config GENERIC_TIME + def_bool y + source "init/Kconfig" source "kernel/Kconfig.freezer" --- a/arch/xtensa/kernel/time.c +++ b/arch/xtensa/kernel/time.c @@ -14,6 +14,7 @@ #include #include +#include #include #include #include @@ -29,6 +30,19 @@ unsigned long ccount_per_jiffy; /* per unsigned long nsec_per_ccount; /* nsec per ccount increment */ #endif +static cycle_t ccount_read(void) +{ + return (cycle_t)get_ccount(); +} + +static struct clocksource ccount_clocksource = { + .name = "ccount", + .rating = 200, + .read = ccount_read, + .mask = CLOCKSOURCE_MASK(32), + .mult = NSEC_PER_CCOUNT, +}; + static irqreturn_t timer_interrupt(int irq, void *dev_id); static struct irqaction timer_irqaction = { .handler = timer_interrupt, @@ -38,9 +52,11 @@ static struct irqaction timer_irqaction void __init time_init(void) { - /* The platform must provide a function to calibrate the processor - * speed for the CALIBRATE. - */ + xtime.tv_nsec = 0; + xtime.tv_sec = read_persistent_clock(); + + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT printk("Calibrating CPU frequency "); @@ -48,12 +64,7 @@ void __init time_init(void) printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ), (int)(ccount_per_jiffy/(10000/HZ))%100); #endif - - xtime.tv_nsec = 0; - xtime.tv_sec = read_persistent_clock(); - - set_normalized_timespec(&wall_to_monotonic, - -xtime.tv_sec, -xtime.tv_nsec); + clocksource_register(&ccount_clocksource); /* Initialize the linux timer interrupt. */ @@ -61,69 +72,6 @@ void __init time_init(void) set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY); } - -int do_settimeofday(struct timespec *tv) -{ - time_t wtm_sec, sec = tv->tv_sec; - long wtm_nsec, nsec = tv->tv_nsec; - unsigned long delta; - - if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; - - write_seqlock_irq(&xtime_lock); - - /* This is revolting. We need to set "xtime" correctly. However, the - * value in this location is the value at the most recent update of - * wall time. Discover what correction gettimeofday() would have - * made, and then undo it! - */ - - delta = CCOUNT_PER_JIFFY; - delta += get_ccount() - get_linux_timer(); - nsec -= delta * NSEC_PER_CCOUNT; - - wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); - wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); - - set_normalized_timespec(&xtime, sec, nsec); - set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); - - ntp_clear(); - write_sequnlock_irq(&xtime_lock); - return 0; -} - -EXPORT_SYMBOL(do_settimeofday); - - -void do_gettimeofday(struct timeval *tv) -{ - unsigned long flags; - unsigned long volatile sec, usec, delta, seq; - - do { - seq = read_seqbegin_irqsave(&xtime_lock, flags); - - sec = xtime.tv_sec; - usec = (xtime.tv_nsec / NSEC_PER_USEC); - - delta = get_linux_timer() - get_ccount(); - - } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); - - usec += (((unsigned long) CCOUNT_PER_JIFFY - delta) - * (unsigned long) NSEC_PER_CCOUNT) / NSEC_PER_USEC; - - for (; usec >= 1000000; sec++, usec -= 1000000) - ; - - tv->tv_sec = sec; - tv->tv_usec = usec; -} - -EXPORT_SYMBOL(do_gettimeofday); - /* * The timer interrupt is called HZ times per second. */ --