Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755204Ab3H1Kot (ORCPT ); Wed, 28 Aug 2013 06:44:49 -0400 Received: from service87.mimecast.com ([91.220.42.44]:48402 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755146Ab3H1Kol (ORCPT ); Wed, 28 Aug 2013 06:44:41 -0400 From: Sudeep KarkadaNagesha To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Sudeep.KarkadaNagesha@arm.com, Lorenzo Pieralisi , Will Deacon , Catalin Marinas , Thomas Gleixner , Daniel Lezcano , Sudeep KarkadaNagesha Subject: [PATCH v5 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer Date: Wed, 28 Aug 2013 11:44:49 +0100 Message-Id: <1377686689-30828-6-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1377686689-30828-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1377686689-30828-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-OriginalArrivalTime: 28 Aug 2013 10:44:39.0204 (UTC) FILETIME=[98806640:01CEA3DB] X-MC-Unique: 113082811444005701 Content-Type: text/plain; charset=WINDOWS-1252 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id r7SAjips005379 Content-Length: 2792 Lines: 91 From: Sudeep KarkadaNagesha Few control settings done in architected timer as part of initialisation can be lost when CPU enters deeper power states. They need to be re-initialised when the CPU is (warm)reset again. This patch adds CPU PM notifiers to do the timer initialisation on warm resets. It also save the event stream divider value calculated during cold reset and uses the same in warm reset path. Cc: Catalin Marinas Reviewed-by: Lorenzo Pieralisi Reviewed-by: Will Deacon Signed-off-by: Sudeep KarkadaNagesha --- drivers/clocksource/arm_arch_timer.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index f42bef4..ffb0bfb 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -281,6 +282,33 @@ static struct notifier_block arch_timer_cpu_nb = { .notifier_call = arch_timer_cpu_notify, }; +#ifdef CONFIG_CPU_PM +static unsigned int saved_cntkctl; +static int arch_timer_cpu_pm_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + if (action == CPU_PM_ENTER) + saved_cntkctl = arch_timer_get_cntkctl(); + else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT) + arch_timer_set_cntkctl(saved_cntkctl); + return NOTIFY_OK; +} + +static struct notifier_block arch_timer_cpu_pm_notifier = { + .notifier_call = arch_timer_cpu_pm_notify, +}; + +static int __init arch_timer_cpu_pm_init(void) +{ + return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier); +} +#else +static int __init arch_timer_cpu_pm_init(void) +{ + return 0; +} +#endif + static int __init arch_timer_register(void) { int err; @@ -330,11 +358,17 @@ static int __init arch_timer_register(void) if (err) goto out_free_irq; + err = arch_timer_cpu_pm_init(); + if (err) + goto out_unreg_notify; + /* Immediately configure the timer on the boot CPU */ arch_timer_setup(this_cpu_ptr(arch_timer_evt)); return 0; +out_unreg_notify: + unregister_cpu_notifier(&arch_timer_cpu_nb); out_free_irq: if (arch_timer_use_virtual) free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt); -- 1.8.1.2 -- 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/