From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751408Ab3FXUbM (ORCPT ); Mon, 24 Jun 2013 16:31:12 -0400 Received: from terminus.zytor.com ([198.137.202.10]:32937 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750745Ab3FXUbH (ORCPT ); Mon, 24 Jun 2013 16:31:07 -0400 Date: Mon, 24 Jun 2013 13:30:51 -0700 From: tip-bot for Mark Rutland Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, mark.rutland@arm.com, sboyd@codeaurora.org, john.stultz@linaro.org, tglx@linutronix.de, daniel.lezcano@linaro.org Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mark.rutland@arm.com, sboyd@codeaurora.org, john.stultz@linaro.org, tglx@linutronix.de, daniel.lezcano@linaro.org In-Reply-To: <1370291642-13259-3-git-send-email-sboyd@codeaurora.org> References: <1370291642-13259-3-git-send-email-sboyd@codeaurora.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] clocksource: Add generic dummy timer driver Git-Commit-ID: 064706514ec3fea740c2656e03c4f01f6a551ac4 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Mon, 24 Jun 2013 13:30:57 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 064706514ec3fea740c2656e03c4f01f6a551ac4 Gitweb: http://git.kernel.org/tip/064706514ec3fea740c2656e03c4f01f6a551ac4 Author: Mark Rutland AuthorDate: Mon, 3 Jun 2013 13:33:53 -0700 Committer: Thomas Gleixner CommitDate: Mon, 24 Jun 2013 22:27:37 +0200 clocksource: Add generic dummy timer driver Several architectures have a dummy timer driver tightly coupled with their broadcast code to support machines without cpu-local timers (or where there is a lack of driver support). Since 12ad100046: "clockevents: Add generic timer broadcast function" it's been possible to write broadcast-capable timer drivers decoupled from the broadcast mechanism. We can use this functionality to implement a generic dummy timer driver that can be shared by all architectures with generic tick broadcast (ARCH_HAS_TICK_BROADCAST). This patch implements a generic dummy timer using this facility. [sboyd: Make percpu data static, use __this_cpu_ptr(), move to early_initcall to properly register on each CPU, only register if more than one CPU possible] Signed-off-by: Mark Rutland Signed-off-by: Stephen Boyd Acked-by: Marc Zyngier , Cc: John Stultz Cc: Daniel Lezcano Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1370291642-13259-3-git-send-email-sboyd@codeaurora.org Signed-off-by: Thomas Gleixner --- drivers/clocksource/Makefile | 1 + drivers/clocksource/dummy_timer.c | 69 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 70 insertions(+) diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 4853ea0..9ba8b4d 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -31,3 +31,4 @@ obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o +obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o diff --git a/drivers/clocksource/dummy_timer.c b/drivers/clocksource/dummy_timer.c new file mode 100644 index 0000000..1f55f96 --- /dev/null +++ b/drivers/clocksource/dummy_timer.c @@ -0,0 +1,69 @@ +/* + * linux/drivers/clocksource/dummy_timer.c + * + * Copyright (C) 2013 ARM Ltd. + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include +#include +#include +#include + +static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt); + +static void dummy_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + /* + * Core clockevents code will call this when exchanging timer devices. + * We don't need to do anything here. + */ +} + +static void __cpuinit dummy_timer_setup(void) +{ + int cpu = smp_processor_id(); + struct clock_event_device *evt = __this_cpu_ptr(&dummy_timer_evt); + + evt->name = "dummy_timer"; + evt->features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_DUMMY; + evt->rating = 100; + evt->set_mode = dummy_timer_set_mode; + evt->cpumask = cpumask_of(cpu); + + clockevents_register_device(evt); +} + +static int __cpuinit dummy_timer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING) + dummy_timer_setup(); + + return NOTIFY_OK; +} + +static struct notifier_block dummy_timer_cpu_nb __cpuinitdata = { + .notifier_call = dummy_timer_cpu_notify, +}; + +static int __init dummy_timer_register(void) +{ + int err = register_cpu_notifier(&dummy_timer_cpu_nb); + if (err) + return err; + + /* We won't get a call on the boot CPU, so register immediately */ + if (num_possible_cpus() > 1) + dummy_timer_setup(); + + return 0; +} +early_initcall(dummy_timer_register);