Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932555Ab3GVLV6 (ORCPT ); Mon, 22 Jul 2013 07:21:58 -0400 Received: from service87.mimecast.com ([91.220.42.44]:42548 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932435Ab3GVLVc (ORCPT ); Mon, 22 Jul 2013 07:21:32 -0400 From: Sudeep KarkadaNagesha To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Sudeep.KarkadaNagesha@arm.com, Mark Rutland , Lorenzo Pieralisi , Russell King , Catalin Marinas , Will Deacon , Sudeep KarkadaNagesha Subject: [PATCH v2 3/3] drivers: clocksource: add CPU PM notifier for ARM architected timer Date: Mon, 22 Jul 2013 12:21:22 +0100 Message-Id: <1374492082-13686-4-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1374492082-13686-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1371575223-21702-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1374492082-13686-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-OriginalArrivalTime: 22 Jul 2013 11:21:29.0496 (UTC) FILETIME=[9CA77180:01CE86CD] X-MC-Unique: 113072212213101001 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 r6MBMJgl009578 Content-Length: 3237 Lines: 108 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. Reviewed-by: Lorenzo Pieralisi Reviewed-by: Will Deacon Signed-off-by: Sudeep KarkadaNagesha --- drivers/clocksource/arm_arch_timer.c | 38 +++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 6301ee5..7057552 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 @@ -39,6 +40,8 @@ static struct clock_event_device __percpu *arch_timer_evt; static bool arch_timer_use_virtual = true; +static int arch_timer_evtstream_div; + /* * Architected system timer support. */ @@ -160,7 +163,9 @@ static int arch_timer_setup(struct clock_event_device *clk) pos = fls(evt_stream_div); if (pos > 1 && !(evt_stream_div & (1 << (pos - 2)))) pos--; - arch_counter_set_user_access(min(pos, 15)); + /* save divider value for use in CPU PM notifier */ + arch_timer_evtstream_div = min(pos, 15); + arch_counter_set_user_access(arch_timer_evtstream_div); return 0; } @@ -267,6 +272,31 @@ static struct notifier_block arch_timer_cpu_nb = { .notifier_call = arch_timer_cpu_notify, }; +#ifdef CONFIG_CPU_PM +static int arch_timer_cpu_pm_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + if (action == CPU_PM_EXIT) + arch_counter_set_user_access(arch_timer_evtstream_div); + + 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; @@ -316,11 +346,17 @@ 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/