From patchwork Thu Aug 29 14:55:42 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep KarkadaNagesha X-Patchwork-Id: 2851474 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id B4E9F9F2F4 for ; Thu, 29 Aug 2013 14:57:39 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 839C22045A for ; Thu, 29 Aug 2013 14:57:38 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1E41C20113 for ; Thu, 29 Aug 2013 14:57:37 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF3eY-0004BA-6g; Thu, 29 Aug 2013 14:56:54 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF3eE-0006wV-3z; Thu, 29 Aug 2013 14:56:34 +0000 Received: from service87.mimecast.com ([91.220.42.44]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VF3dY-0006pT-Ai for linux-arm-kernel@lists.infradead.org; Thu, 29 Aug 2013 14:56:02 +0000 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Thu, 29 Aug 2013 15:55:29 +0100 Received: from e103737-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Thu, 29 Aug 2013 15:55:28 +0100 From: Sudeep KarkadaNagesha To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130829_105552_667279_4BCB8D41 X-CRM114-Status: GOOD ( 13.31 ) X-Spam-Score: -2.6 (--) Cc: Lorenzo Pieralisi , Sudeep KarkadaNagesha , Catalin Marinas , Daniel Lezcano , Will Deacon , Thomas Gleixner X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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);