Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752157Ab3IRLFm (ORCPT ); Wed, 18 Sep 2013 07:05:42 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:60739 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751556Ab3IRLF1 (ORCPT ); Wed, 18 Sep 2013 07:05:27 -0400 From: Sudeep KarkadaNagesha To: arm@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Sudeep.KarkadaNagesha@arm.com, Daniel Lezcano , Sudeep KarkadaNagesha Subject: [PATCH v6 RESEND 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer Date: Wed, 18 Sep 2013 12:05:06 +0100 Message-Id: <1379502306-12911-6-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1379502306-12911-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1379502306-12911-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2744 Lines: 89 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. Reviewed-by: 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 105f8ff..9338f1a 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 @@ -475,6 +476,33 @@ 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; @@ -514,11 +542,17 @@ 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/