From patchwork Thu Jul 25 09:03:09 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Preeti U Murthy X-Patchwork-Id: 261639 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 894382C02F9 for ; Thu, 25 Jul 2013 19:09:07 +1000 (EST) Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp05.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 280572C00E6 for ; Thu, 25 Jul 2013 19:06:08 +1000 (EST) Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 25 Jul 2013 18:59:01 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id D64FB2BB0052 for ; Thu, 25 Jul 2013 19:05:35 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r6P8oA9k60096732 for ; Thu, 25 Jul 2013 18:50:10 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r6P95VOk015759 for ; Thu, 25 Jul 2013 19:05:34 +1000 Received: from preeti.in.ibm.com (preeti.in.ibm.com [9.124.35.49]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r6P95QfV015617; Thu, 25 Jul 2013 19:05:27 +1000 Subject: [RFC PATCH 5/5] cpuidle/ppc: Add longnap state to the idle states on powernv To: benh@kernel.crashing.org, paul.gortmaker@windriver.com, paulus@samba.org, shangw@linux.vnet.ibm.com, galak@kernel.crashing.org, fweisbec@gmail.com, paulmck@linux.vnet.ibm.com, michael@ellerman.id.au, arnd@arndb.de, linux-pm@vger.kernel.org, rostedt@goodmis.org, rjw@sisk.pl, john.stultz@linaro.org, tglx@linutronix.de, chenhui.zhao@freescale.com, deepthi@linux.vnet.ibm.com, geoff@infradead.org, linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com, schwidefsky@de.ibm.com, svaidy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org From: Preeti U Murthy Date: Thu, 25 Jul 2013 14:33:09 +0530 Message-ID: <20130725090309.12500.20286.stgit@preeti.in.ibm.com> In-Reply-To: <20130725090016.12500.28888.stgit@preeti.in.ibm.com> References: <20130725090016.12500.28888.stgit@preeti.in.ibm.com> User-Agent: StGit/0.16-38-g167d MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13072508-1396-0000-0000-000003507B2B X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" This patch hooks into the existing broadcast framework with the support that this patchset introduces for ppc, and the cpuidle driver backend for powernv(posted out recently by Deepthi Dharwar) to add sleep state as one of the deep idle states, in which the decrementer is switched off. However in this patch, we only emulate sleep by going into a state which does a nap with the decrementer interrupts disabled, termed as longnap. This enables focus on the timer broadcast framework for ppc in this series of patches , which is required as a first step to enable sleep on ppc. Signed-off-by: Preeti U Murthy --- arch/powerpc/platforms/powernv/processor_idle.c | 48 +++++++++++++++++++++++ 1 file changed, 47 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/powernv/processor_idle.c b/arch/powerpc/platforms/powernv/processor_idle.c index f43ad91a..9aca502 100644 --- a/arch/powerpc/platforms/powernv/processor_idle.c +++ b/arch/powerpc/platforms/powernv/processor_idle.c @@ -9,16 +9,18 @@ #include #include #include +#include #include #include +#include struct cpuidle_driver powernv_idle_driver = { .name = "powernv_idle", .owner = THIS_MODULE, }; -#define MAX_IDLE_STATE_COUNT 2 +#define MAX_IDLE_STATE_COUNT 3 static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; static struct cpuidle_device __percpu *powernv_cpuidle_devices; @@ -54,6 +56,43 @@ static int nap_loop(struct cpuidle_device *dev, return index; } +/* Emulate sleep, with long nap. + * During sleep, the core does not receive decrementer interrupts. + * Emulate sleep using long nap with decrementers interrupts disabled. + * This is an initial prototype to test the timer offload framework for ppc. + * We will eventually introduce the sleep state once the timer offload framework + * for ppc is stable. + */ +static int longnap_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + int cpu = dev->cpu; + + unsigned long lpcr = mfspr(SPRN_LPCR); + + lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */ + + /* exit powersave upon external interrupt, but not decrementer + * interrupt, Emulate sleep. + */ + lpcr |= LPCR_PECE0; + + if (cpu != bc_cpu) { + mtspr(SPRN_LPCR, lpcr); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); + power7_nap(); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); + } else { + /* Wakeup on a decrementer interrupt, Do a nap */ + lpcr |= LPCR_PECE1; + mtspr(SPRN_LPCR, lpcr); + power7_nap(); + } + + return index; +} + /* * States for dedicated partition case. */ @@ -72,6 +111,13 @@ static struct cpuidle_state powernv_states[MAX_IDLE_STATE_COUNT] = { .exit_latency = 10, .target_residency = 100, .enter = &nap_loop }, + { /* LongNap */ + .name = "LongNap", + .desc = "LongNap", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 10, + .target_residency = 100, + .enter = &longnap_loop }, }; static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,