From patchwork Thu Nov 3 00:59:23 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 123378 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 560DEB7218 for ; Thu, 3 Nov 2011 12:03:50 +1100 (EST) Received: from localhost (ppp121-44-79-234.lns20.syd6.internode.on.net [121.44.79.234]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPSA id 130E6B6F8F; Thu, 3 Nov 2011 12:03:35 +1100 (EST) X-Mailbox-Line: From anton@samba.org Thu Nov 3 12:01:11 2011 Message-Id: <20111103010111.868598561@samba.org> User-Agent: quilt/0.48-1 Date: Thu, 03 Nov 2011 11:59:23 +1100 From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org, johnstul@us.ibm.com Subject: [PATCH 1/4] powerpc/time: Use clockevents_calc_mult_shift References: <20111103005922.854058953@samba.org> Content-Disposition: inline; filename=clock2 Cc: linuxppc-dev@lists.ozlabs.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org We can use clockevents_calc_mult_shift instead of doing all the work ourselves. Signed-off-by: Anton Blanchard Index: linux-build/arch/powerpc/kernel/time.c =================================================================== --- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:55.225606490 +1100 +++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100 @@ -112,8 +112,6 @@ static void decrementer_set_mode(enum cl static struct clock_event_device decrementer_clockevent = { .name = "decrementer", .rating = 200, - .shift = 0, /* To be filled in */ - .mult = 0, /* To be filled in */ .irq = 0, .set_next_event = decrementer_set_next_event, .set_mode = decrementer_set_mode, @@ -904,31 +902,6 @@ static void decrementer_set_mode(enum cl decrementer_set_next_event(DECREMENTER_MAX, dev); } -static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, - int shift) -{ - uint64_t tmp = ((uint64_t)ticks) << shift; - - do_div(tmp, nsec); - return tmp; -} - -static void __init setup_clockevent_multiplier(unsigned long hz) -{ - u64 mult, shift = 32; - - while (1) { - mult = div_sc64(hz, NSEC_PER_SEC, shift); - if (mult && (mult >> 32UL) == 0UL) - break; - - shift--; - } - - decrementer_clockevent.shift = shift; - decrementer_clockevent.mult = mult; -} - static void register_decrementer_clockevent(int cpu) { struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; @@ -946,7 +919,8 @@ static void __init init_decrementer_cloc { int cpu = smp_processor_id(); - setup_clockevent_multiplier(ppc_tb_freq); + clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); + decrementer_clockevent.max_delta_ns = clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); decrementer_clockevent.min_delta_ns =