From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755529Ab3H2Oze (ORCPT ); Thu, 29 Aug 2013 10:55:34 -0400 Received: from service87.mimecast.com ([91.220.42.44]:41356 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754885Ab3H2Oza (ORCPT ); Thu, 29 Aug 2013 10:55:30 -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 v6 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer Date: Thu, 29 Aug 2013 15:55:42 +0100 Message-Id: <1377788142-21388-6-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1377788142-21388-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1377788142-21388-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-OriginalArrivalTime: 29 Aug 2013 14:55:28.0103 (UTC) FILETIME=[CCC1E770:01CEA4C7] X-MC-Unique: 113082915552901401 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 r7TEtlUm015631 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 restored when the CPU is (warm)reset again. This patch adds CPU PM notifiers to save the counter control register when entering low power modes and restore it when CPU exits low power. 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 9777b36..611f9cb 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 @@ -275,6 +276,33 @@ 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; @@ -324,11 +352,17 @@ 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep.KarkadaNagesha@arm.com (Sudeep KarkadaNagesha) Date: Thu, 29 Aug 2013 15:55:42 +0100 Subject: [PATCH v6 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer In-Reply-To: <1377788142-21388-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1377788142-21388-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> Message-ID: <1377788142-21388-6-git-send-email-Sudeep.KarkadaNagesha@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 restored when the CPU is (warm)reset again. This patch adds CPU PM notifiers to save the counter control register when entering low power modes and restore it when CPU exits low power. 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 9777b36..611f9cb 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 @@ -275,6 +276,33 @@ 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; @@ -324,11 +352,17 @@ 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