Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755672Ab3HWQUj (ORCPT ); Fri, 23 Aug 2013 12:20:39 -0400 Received: from service87.mimecast.com ([91.220.42.44]:56152 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754155Ab3HWQU2 (ORCPT ); Fri, 23 Aug 2013 12:20:28 -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 v4 5/5] drivers: clocksource: add CPU PM notifier for ARM architected timer Date: Fri, 23 Aug 2013 17:19:09 +0100 Message-Id: <1377274749-6196-6-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1377274749-6196-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1377274749-6196-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> X-OriginalArrivalTime: 23 Aug 2013 16:20:24.0204 (UTC) FILETIME=[ABCAB4C0:01CEA01C] X-MC-Unique: 113082317202608101 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 r7NGKm6A007985 Content-Length: 3817 Lines: 125 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 | 47 +++++++++++++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index e331818..1d5b75d 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 @@ -124,6 +125,12 @@ static int arch_timer_set_next_event_phys(unsigned long evt, } #ifdef CONFIG_ARM_ARCH_TIMER_EVTSTREAM +static int arch_timer_evtstream_div; +static void arch_timer_evtstream_reset(void) +{ + /* enable event stream */ + arch_timer_evtstrm_config(true, arch_timer_evtstream_div); +} static void arch_timer_setup_evtstream(void) { int evt_stream_div, pos; @@ -133,16 +140,19 @@ static void arch_timer_setup_evtstream(void) pos = fls(evt_stream_div); if (pos > 1 && !(evt_stream_div & (1 << (pos - 2)))) pos--; - /* enable event stream */ - arch_timer_evtstrm_config(true, min(pos, 15)); + /* save divider value for use in CPU PM notifier */ + arch_timer_evtstream_div = min(pos, 15); + arch_timer_evtstream_reset(); /* enable hwcap definition to the users for event stream feature */ arch_timer_set_hwcap_evtstrm(); } #else -static void arch_timer_setup_evtstream(void) +static void arch_timer_evtstream_reset(void) { + /* disable event stream */ arch_timer_evtstrm_config(false, 0); } +#define arch_timer_setup_evtstream arch_timer_evtstream_reset #endif static int arch_timer_setup(struct clock_event_device *clk) @@ -283,6 +293,31 @@ 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_timer_evtstream_reset(); + + 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; @@ -332,11 +367,17 @@ 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/