Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754539Ab3FEXzm (ORCPT ); Wed, 5 Jun 2013 19:55:42 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:60380 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753582Ab3FEXyt (ORCPT ); Wed, 5 Jun 2013 19:54:49 -0400 From: Stephen Boyd To: John Stultz Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Russell King , arm@kernel.org, Catalin Marinas , Will Deacon , Thomas Gleixner , Christopher Covington Subject: [PATCHv3 2/3] ARM: arch_timer: Move to generic sched_clock framework Date: Wed, 5 Jun 2013 16:54:44 -0700 Message-Id: <1370476485-468-3-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 1.8.3.rc3.8.g5e49f30.dirty In-Reply-To: <1370476485-468-1-git-send-email-sboyd@codeaurora.org> References: <1370476485-468-1-git-send-email-sboyd@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3522 Lines: 98 Register with the generic sched_clock framework now that it supports 64 bits. This fixes two problems with the current sched_clock support for machines using the architected timers. First off, we don't subtract the start value from subsequent sched_clock calls so we can potentially start off with sched_clock returning gigantic numbers. Second, there is no support for suspend/resume handling so problems such as discussed in 6a4dae5 (ARM: 7565/1: sched: stop sched_clock() during suspend, 2012-10-23) can happen without this patch. Signed-off-by: Stephen Boyd --- arch/arm/kernel/arch_timer.c | 14 ++------------ include/linux/sched_clock.h | 2 -- kernel/time/sched_clock.c | 13 ++++--------- 3 files changed, 6 insertions(+), 23 deletions(-) diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index 221f07b..2966288 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c @@ -22,13 +22,6 @@ static unsigned long arch_timer_read_counter_long(void) return arch_timer_read_counter(); } -static u32 sched_clock_mult __read_mostly; - -static unsigned long long notrace arch_timer_sched_clock(void) -{ - return arch_timer_read_counter() * sched_clock_mult; -} - static struct delay_timer arch_delay_timer; static void __init arch_timer_delay_timer_register(void) @@ -48,11 +41,8 @@ int __init arch_timer_arch_init(void) arch_timer_delay_timer_register(); - /* Cache the sched_clock multiplier to save a divide in the hot path. */ - sched_clock_mult = NSEC_PER_SEC / arch_timer_rate; - sched_clock_func = arch_timer_sched_clock; - pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %uns\n", - arch_timer_rate / 1000, sched_clock_mult); + /* 56 bits minimum, so we assume worst case rollover */ + sched_clock_setup(arch_timer_read_counter, 56, arch_timer_rate); return 0; } diff --git a/include/linux/sched_clock.h b/include/linux/sched_clock.h index 81baaef..04cee83 100644 --- a/include/linux/sched_clock.h +++ b/include/linux/sched_clock.h @@ -17,6 +17,4 @@ static inline void sched_clock_postinit(void) { } extern void setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate); extern void sched_clock_setup(u64 (*read)(void), int bits, unsigned long rate); -extern unsigned long long (*sched_clock_func)(void); - #endif diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 3478b6d..f69addf 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -173,20 +173,15 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate) sched_clock_setup(read_sched_clock_32_wrapper, bits, rate); } -static unsigned long long notrace sched_clock_32(void) -{ - u64 cyc = read_sched_clock(); - return cyc_to_sched_clock(cyc, sched_clock_mask); -} - -unsigned long long __read_mostly (*sched_clock_func)(void) = sched_clock_32; - unsigned long long notrace sched_clock(void) { + u64 cyc; + if (cd.suspended) return cd.epoch_ns; - return sched_clock_func(); + cyc = read_sched_clock(); + return cyc_to_sched_clock(cyc, sched_clock_mask); } void __init sched_clock_postinit(void) -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- 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/