diff options
Diffstat (limited to 'drivers/acpi/processor_aggregator.c')
| -rw-r--r-- | drivers/acpi/processor_aggregator.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/drivers/acpi/processor_aggregator.c b/drivers/acpi/processor_aggregator.c new file mode 100644 index 000000000000..d73ae57f7a6d --- /dev/null +++ b/drivers/acpi/processor_aggregator.c @@ -0,0 +1,389 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ +#include <linux/kernel.h> +#include <linux/cpumask.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/kthread.h> +#include <linux/freezer.h> +#include <linux/cpu.h> +#include <linux/clockchips.h> +#include <acpi/acpi_bus.h> +#include <acpi/acpi_drivers.h> + +#define ACPI_PROCESSOR_AGGREGATOR_CLASS "processor_aggregator" +#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" +#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 +static DEFINE_MUTEX(isolated_cpus_lock); + +#define MWAIT_SUBSTATE_MASK (0xf) +#define MWAIT_CSTATE_MASK (0xf) +#define MWAIT_SUBSTATE_SIZE (4) +#define CPUID_MWAIT_LEAF (5) +#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1) +#define CPUID5_ECX_INTERRUPT_BREAK (0x2) +static unsigned long power_saving_mwait_eax; +static void power_saving_mwait_init(void) +{ + unsigned int eax, ebx, ecx, edx; + unsigned int highest_cstate = 0; + unsigned int highest_subcstate = 0; + int i; + + if (!boot_cpu_has(X86_FEATURE_MWAIT)) + return; + if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF) + return; + + cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx); + + if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) || + !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) + return; + + edx >>= MWAIT_SUBSTATE_SIZE; + for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { + if (edx & MWAIT_SUBSTATE_MASK) { + highest_cstate = i; + highest_subcstate = edx & MWAIT_SUBSTATE_MASK; + } + } + power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) | + (highest_subcstate - 1); + + for_each_online_cpu(i) + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &i); + +#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86) + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + case X86_VENDOR_INTEL: + /* + * AMD Fam10h TSC will tick in all + * C/P/S0/S1 states when this bit is set. + */ + if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) + return; + + /*FALL THROUGH*/ + default: + /* TSC could halt in idle, so notify users */ + mark_tsc_unstable("TSC halts in idle"); + } +#endif +} + +static int power_saving_thread(void *data) +{ + struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1}; + int do_sleep; + + /* + * we just create a RT task to do power saving. Scheduler will migrate + * the task to any CPU. + */ + sched_setscheduler(current, SCHED_RR, ¶m); + + while (!kthread_should_stop()) { + int cpu; + u64 expire_time; + + try_to_freeze(); + + do_sleep = 0; + + current_thread_info()->status &= ~TS_POLLING; + /* + * TS_POLLING-cleared state must be visible before we test + * NEED_RESCHED: + */ + smp_mb(); + + expire_time = jiffies + HZ * 95 /100; + + while (!need_resched()) { + local_irq_disable(); + cpu = smp_processor_id(); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); + stop_critical_timings(); + + __monitor((void *)¤t_thread_info()->flags, 0, 0); + smp_mb(); + if (!need_resched()) + __mwait(power_saving_mwait_eax, 1); + + start_critical_timings(); + clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu); + local_irq_enable(); + + if (jiffies > expire_time) { + do_sleep = 1; + break; + } + } + + current_thread_info()->status |= TS_POLLING; + + /* + * current sched_rt has threshold for rt task running time. + * When a rt task uses 95% CPU time, the rt thread will be + * scheduled out for 5% CPU time to not starve other tasks. But + * the mechanism only works when all CPUs have RT task running, + * as if one CPU hasn't RT task, RT task from other CPUs will + * borrow CPU time from this CPU and cause RT task use > 95% + * CPU time. To make 'avoid staration' work, takes a nap here. + */ + if (do_sleep) + schedule_timeout_killable(HZ * 5 /100); + } + return 0; +} + +static struct task_struct *ps_tsks[NR_CPUS]; +static unsigned int ps_tsk_num; +static int create_power_saving_task(void) +{ + ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread, NULL, + "power_saving/%d", ps_tsk_num); + if (ps_tsks[ps_tsk_num]) { + ps_tsk_num++; + return 0; + } + return -EINVAL; +} + +static void destroy_power_saving_task(void) +{ + if (ps_tsk_num > 0) { + ps_tsk_num--; + kthread_stop(ps_tsks[ps_tsk_num]); + } +} + +static void set_power_saving_task_num(unsigned int num) +{ + if (num > ps_tsk_num) { + while (ps_tsk_num < num) { + if (create_power_saving_task()) + return; + } + } else if (num < ps_tsk_num) { + while (ps_tsk_num > num) + destroy_power_saving_task(); + } +} + +static int acpi_processor_aggregator_idle_cpus(unsigned int num_cpus) +{ + get_online_cpus(); + + num_cpus = min_t(unsigned int, num_cpus, num_online_cpus()); + set_power_saving_task_num(num_cpus); + + put_online_cpus(); + return 0; +} + +static uint32_t acpi_processor_aggregator_idle_cpus_num(void) +{ + return ps_tsk_num; +} + +static ssize_t acpi_processor_aggregator_idlecpus_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + unsigned long num; + if (strict_strtoul(buf, 0, &num)) + return -EINVAL; + mutex_lock(&isolated_cpus_lock); + acpi_processor_aggregator_idle_cpus(num); + mutex_unlock(&isolated_cpus_lock); + return count; +} + +static ssize_t acpi_processor_aggregator_idlecpus_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return scnprintf(buf, PAGE_SIZE, "%d", + acpi_processor_aggregator_idle_cpus_num()); +} +static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR, + acpi_processor_aggregator_idlecpus_show, + acpi_processor_aggregator_idlecpus_store); + +static int acpi_processor_aggregator_add_sysfs(struct acpi_device *device) +{ + int result; + + result = device_create_file(&device->dev, &dev_attr_idlecpus); + if (result) + return -ENODEV; + return 0; +} + +static void acpi_processor_aggregator_remove_sysfs(struct acpi_device *device) +{ + device_remove_file(&device->dev, &dev_attr_idlecpus); +} + +/* Query firmware how many CPUs should be idle */ +static int acpi_processor_aggregator_pur(acpi_handle handle, int *num_cpus) +{ + struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; + acpi_status status; + union acpi_object *package; + int rev, num, ret = -EINVAL; + + status = acpi_evaluate_object(handle, "_PUR", NULL, &buffer); + if (ACPI_FAILURE(status)) + return -EINVAL; + package = buffer.pointer; + if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2) + goto out; + rev = package->package.elements[0].integer.value; + num = package->package.elements[1].integer.value; + if (rev != 1) + goto out; + *num_cpus = num; + ret = 0; +out: + kfree(buffer.pointer); + return ret; +} + +/* Notify firmware how many CPUs are idle */ +static void acpi_processor_aggregator_ost(acpi_handle handle, int stat, + uint32_t idle_cpus) +{ + union acpi_object params[3] = { + {.type = ACPI_TYPE_INTEGER,}, + {.type = ACPI_TYPE_INTEGER,}, + {.type = ACPI_TYPE_BUFFER,}, + }; + struct acpi_object_list arg_list = {3, params}; + + params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY; + params[1].integer.value = stat; + params[2].buffer.length = 4; + params[2].buffer.pointer = (void *)&idle_cpus; + acpi_evaluate_object(handle, "_OST", &arg_list, NULL); +} + +static void acpi_processor_aggregator_handle_notify(acpi_handle handle) +{ + int num_cpus, ret; + uint32_t idle_cpus; + + mutex_lock(&isolated_cpus_lock); + if (acpi_processor_aggregator_pur(handle, &num_cpus)) { + mutex_unlock(&isolated_cpus_lock); + return; + } + ret = acpi_processor_aggregator_idle_cpus(num_cpus); + idle_cpus = acpi_processor_aggregator_idle_cpus_num(); + if (!ret) + acpi_processor_aggregator_ost(handle, 0, idle_cpus); + else + acpi_processor_aggregator_ost(handle, 1, 0); + mutex_unlock(&isolated_cpus_lock); +} + +static void acpi_processor_aggregator_notify(acpi_handle handle, u32 event, + void *data) +{ + struct acpi_device *device = data; + + switch (event) { + case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: + acpi_processor_aggregator_handle_notify(handle); + acpi_bus_generate_proc_event(device, event, 0); + acpi_bus_generate_netlink_event(device->pnp.device_class, + dev_name(&device->dev), event, 0); + break; + default: + printk(KERN_WARNING"Unsupported event [0x%x]\n", event); + break; + } +} + +static int acpi_processor_aggregator_add(struct acpi_device *device) +{ + acpi_status status; + + strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); + strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); + + if (acpi_processor_aggregator_add_sysfs(device)) + return -ENODEV; + + status = acpi_install_notify_handler(device->handle, + ACPI_DEVICE_NOTIFY, acpi_processor_aggregator_notify, device); + if (ACPI_FAILURE(status)) { + acpi_processor_aggregator_remove_sysfs(device); + return -ENODEV; + } + + return 0; +} + +static int acpi_processor_aggregator_remove(struct acpi_device *device, int type) +{ + mutex_lock(&isolated_cpus_lock); + acpi_processor_aggregator_idle_cpus(0); + mutex_unlock(&isolated_cpus_lock); + + acpi_remove_notify_handler(device->handle, + ACPI_DEVICE_NOTIFY, acpi_processor_aggregator_notify); + acpi_processor_aggregator_remove_sysfs(device); + return 0; +} + +static const struct acpi_device_id processor_aggregator_device_ids[] = { + {"ACPI000C", 0}, + {"", 0}, +}; +MODULE_DEVICE_TABLE(acpi, processor_aggregator_device_ids); + +static struct acpi_driver acpi_processor_aggregator_driver = { + .name = "processor_aggregator", + .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, + .ids = processor_aggregator_device_ids, + .ops = { + .add = acpi_processor_aggregator_add, + .remove = acpi_processor_aggregator_remove, + }, +}; + +static int __init acpi_processor_aggregator_init(void) +{ + power_saving_mwait_init(); + if (power_saving_mwait_eax == 0) + return -EINVAL; + + return acpi_bus_register_driver(&acpi_processor_aggregator_driver); +} + +static void __exit acpi_processor_aggregator_exit(void) +{ + acpi_bus_unregister_driver(&acpi_processor_aggregator_driver); +} + +module_init(acpi_processor_aggregator_init); +module_exit(acpi_processor_aggregator_exit); +MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>"); +MODULE_DESCRIPTION("ACPI Processor Aggregator Driver"); +MODULE_LICENSE("GPL"); |