Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755861Ab3GWJC5 (ORCPT ); Tue, 23 Jul 2013 05:02:57 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:59920 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753556Ab3GWJCi (ORCPT ); Tue, 23 Jul 2013 05:02:38 -0400 Subject: [PATCH 1/3] cpuidle/powernv: cpuidle backend driver for powernv To: linuxppc-dev@lists.ozlabs.org From: Deepthi Dharwar Cc: benh@kernel.crashing.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Date: Tue, 23 Jul 2013 14:31:41 +0530 Message-ID: <20130723090137.7291.36657.stgit@deepthi.in.ibm.com> In-Reply-To: <20130723090111.7291.99479.stgit@deepthi.in.ibm.com> References: <20130723090111.7291.99479.stgit@deepthi.in.ibm.com> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13072308-8878-0000-0000-000008127149 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7333 Lines: 290 This patch implements a back-end cpuidle driver for powernv calling power7_nap and snooze idle states. This can be extended by adding more idle states in the future to the existing framework. Signed-off-by: Deepthi Dharwar --- arch/powerpc/platforms/powernv/Kconfig | 9 + arch/powerpc/platforms/powernv/Makefile | 1 arch/powerpc/platforms/powernv/processor_idle.c | 239 +++++++++++++++++++++++ 3 files changed, 249 insertions(+) create mode 100644 arch/powerpc/platforms/powernv/processor_idle.c diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig index c24684c..ace2d22 100644 --- a/arch/powerpc/platforms/powernv/Kconfig +++ b/arch/powerpc/platforms/powernv/Kconfig @@ -20,3 +20,12 @@ config PPC_POWERNV_RTAS default y select PPC_ICS_RTAS select PPC_RTAS + +config POWERNV_IDLE + bool "CPUIdle driver for powernv platform" + depends on CPU_IDLE + depends on PPC_POWERNV + default y + help + Select this option to enable processor idle state management + through cpuidle subsystem. diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile index 7fe5951..c0e44eb 100644 --- a/arch/powerpc/platforms/powernv/Makefile +++ b/arch/powerpc/platforms/powernv/Makefile @@ -4,3 +4,4 @@ obj-y += opal-rtc.o opal-nvram.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_PCI) += pci.o pci-p5ioc2.o pci-ioda.o obj-$(CONFIG_EEH) += eeh-ioda.o eeh-powernv.o +obj-$(CONFIG_POWERNV_IDLE) += processor_idle.o diff --git a/arch/powerpc/platforms/powernv/processor_idle.c b/arch/powerpc/platforms/powernv/processor_idle.c new file mode 100644 index 0000000..f43ad91a --- /dev/null +++ b/arch/powerpc/platforms/powernv/processor_idle.c @@ -0,0 +1,239 @@ +/* + * processor_idle - idle state cpuidle driver. + */ + +#include +#include +#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 + +static int max_idle_state = MAX_IDLE_STATE_COUNT - 1; +static struct cpuidle_device __percpu *powernv_cpuidle_devices; +static struct cpuidle_state *cpuidle_state_table; + +static int snooze_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + int cpu = dev->cpu; + + local_irq_enable(); + set_thread_flag(TIF_POLLING_NRFLAG); + + while ((!need_resched()) && cpu_online(cpu)) { + ppc64_runlatch_off(); + HMT_very_low(); + } + + HMT_medium(); + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb(); + return index; +} + + +static int nap_loop(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + ppc64_runlatch_off(); + power7_idle(); + return index; +} + +/* + * States for dedicated partition case. + */ +static struct cpuidle_state powernv_states[MAX_IDLE_STATE_COUNT] = { + { /* Snooze */ + .name = "snooze", + .desc = "snooze", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 0, + .target_residency = 0, + .enter = &snooze_loop }, + { /* Nap */ + .name = "Nap", + .desc = "Nap", + .flags = CPUIDLE_FLAG_TIME_VALID, + .exit_latency = 10, + .target_residency = 100, + .enter = &nap_loop }, +}; + +static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n, + unsigned long action, void *hcpu) +{ + int hotcpu = (unsigned long)hcpu; + struct cpuidle_device *dev = + per_cpu_ptr(powernv_cpuidle_devices, hotcpu); + + if (dev && cpuidle_get_driver()) { + switch (action) { + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + cpuidle_pause_and_lock(); + cpuidle_enable_device(dev); + cpuidle_resume_and_unlock(); + break; + + case CPU_DEAD: + case CPU_DEAD_FROZEN: + cpuidle_pause_and_lock(); + cpuidle_disable_device(dev); + cpuidle_resume_and_unlock(); + break; + + default: + return NOTIFY_DONE; + } + } + return NOTIFY_OK; +} + +static struct notifier_block setup_hotplug_notifier = { + .notifier_call = powernv_cpuidle_add_cpu_notifier, +}; + +/* + * powernv_cpuidle_driver_init() + */ +static int powernv_cpuidle_driver_init(void) +{ + int idle_state; + struct cpuidle_driver *drv = &powernv_idle_driver; + + drv->state_count = 0; + + for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) { + + if (idle_state > max_idle_state) + break; + + /* is the state not enabled? */ + if (cpuidle_state_table[idle_state].enter == NULL) + continue; + + drv->states[drv->state_count] = /* structure copy */ + cpuidle_state_table[idle_state]; + + drv->state_count += 1; + } + + return 0; +} + +/* powernv_idle_devices_uninit(void) + * unregister cpuidle devices and de-allocate memory + */ +static void powernv_idle_devices_uninit(void) +{ + int i; + struct cpuidle_device *dev; + + for_each_possible_cpu(i) { + dev = per_cpu_ptr(powernv_cpuidle_devices, i); + cpuidle_unregister_device(dev); + } + + free_percpu(powernv_cpuidle_devices); + return; +} + +/* powernv_idle_devices_init() + * allocate, initialize and register cpuidle device + */ +static int powernv_idle_devices_init(void) +{ + int i; + struct cpuidle_driver *drv = &powernv_idle_driver; + struct cpuidle_device *dev; + + powernv_cpuidle_devices = alloc_percpu(struct cpuidle_device); + if (powernv_cpuidle_devices == NULL) + return -ENOMEM; + + for_each_possible_cpu(i) { + dev = per_cpu_ptr(powernv_cpuidle_devices, i); + dev->state_count = drv->state_count; + dev->cpu = i; + if (cpuidle_register_device(dev)) { + printk(KERN_DEBUG \ + "cpuidle_register_device %d failed!\n", i); + return -EIO; + } + } + return 0; +} + +/* + * powernv_idle_probe() + * Choose state table for shared versus dedicated partition + */ +static int powernv_idle_probe(void) +{ + + if (cpuidle_disable != IDLE_NO_OVERRIDE) + return -ENODEV; + + cpuidle_state_table = powernv_states; + return 0; +} + +static int __init powernv_processor_idle_init(void) +{ + int retval; + + retval = powernv_idle_probe(); + if (retval) + return retval; + + powernv_cpuidle_driver_init(); + retval = cpuidle_register_driver(&powernv_idle_driver); + if (retval) { + printk(KERN_DEBUG "Registration of powernv driver failed.\n"); + return retval; + } + + retval = powernv_idle_devices_init(); + if (retval) { + powernv_idle_devices_uninit(); + cpuidle_unregister_driver(&powernv_idle_driver); + return retval; + } + + register_cpu_notifier(&setup_hotplug_notifier); + printk(KERN_DEBUG "powernv_idle_driver registered\n"); + + return 0; +} + +static void __exit powernv_processor_idle_exit(void) +{ + + unregister_cpu_notifier(&setup_hotplug_notifier); + powernv_idle_devices_uninit(); + cpuidle_unregister_driver(&powernv_idle_driver); + + return; +} + +module_init(powernv_processor_idle_init); +module_exit(powernv_processor_idle_exit); + +MODULE_AUTHOR("Deepthi Dharwar "); +MODULE_DESCRIPTION("Cpuidle driver for POWERNV"); +MODULE_LICENSE("GPL"); -- 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/