From patchwork Wed Aug 14 11:56:23 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: 267106 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 809342C0943 for ; Wed, 14 Aug 2013 22:01:48 +1000 (EST) Received: from e23smtp02.au.ibm.com (e23smtp02.au.ibm.com [202.81.31.144]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp02.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id E54BD2C01E2 for ; Wed, 14 Aug 2013 21:59:05 +1000 (EST) Received: from /spool/local by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 14 Aug 2013 21:48:00 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 36EC73578052 for ; Wed, 14 Aug 2013 21:59:01 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r7EBwokR8323456 for ; Wed, 14 Aug 2013 21:58:50 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r7EBwxiq007771 for ; Wed, 14 Aug 2013 21:59:01 +1000 Received: from preeti.in.ibm.com (preeti.in.ibm.com [9.124.35.218] (may be forged)) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r7EBwl6Z007610; Wed, 14 Aug 2013 21:58:55 +1000 Subject: [RFC V2 PATCH 4/6] cpuidle/ppc: Add longnap state to the idle states on powernv To: fweisbec@gmail.com, paul.gortmaker@windriver.com, paulus@samba.org, shangw@linux.vnet.ibm.com, galak@kernel.crashing.org, deepthi@linux.vnet.ibm.com, benh@kernel.crashing.org, paulmck@linux.vnet.ibm.com, 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, michael@ellerman.id.au, r58472@freescale.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: Wed, 14 Aug 2013 17:26:23 +0530 Message-ID: <20130814115623.5193.36974.stgit@preeti.in.ibm.com> In-Reply-To: <20130814115311.5193.32212.stgit@preeti.in.ibm.com> References: <20130814115311.5193.32212.stgit@preeti.in.ibm.com> User-Agent: StGit/0.16-38-g167d MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13081411-5490-0000-0000-000003FC5F8F 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 along with the support that this patchset introduces for ppc, and the cpuidle driver backend for powernv(posted out by Deepthi Dharwar:https://lkml.org/lkml/2013/7/23/128) 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,