![John Stultz](/assets/img/avatar_default.png)
Now that all arches have been converted over to use generic time via clocksources or arch_gettimeoffset(), we can remove the GENERIC_TIME config option and simplify the generic code. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1279068988-21864-4-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
532 lines
14 KiB
C
532 lines
14 KiB
C
/*
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* acpi_pad.c ACPI Processor Aggregator Driver
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*
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* Copyright (c) 2009, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/cpumask.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/kthread.h>
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#include <linux/freezer.h>
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#include <linux/cpu.h>
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#include <linux/clockchips.h>
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#include <linux/slab.h>
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#include <acpi/acpi_bus.h>
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#include <acpi/acpi_drivers.h>
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#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
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#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
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#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
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static DEFINE_MUTEX(isolated_cpus_lock);
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#define MWAIT_SUBSTATE_MASK (0xf)
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#define MWAIT_CSTATE_MASK (0xf)
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#define MWAIT_SUBSTATE_SIZE (4)
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#define CPUID_MWAIT_LEAF (5)
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#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
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#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
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static unsigned long power_saving_mwait_eax;
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static unsigned char tsc_detected_unstable;
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static unsigned char tsc_marked_unstable;
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static unsigned char lapic_detected_unstable;
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static unsigned char lapic_marked_unstable;
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static void power_saving_mwait_init(void)
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{
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unsigned int eax, ebx, ecx, edx;
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unsigned int highest_cstate = 0;
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unsigned int highest_subcstate = 0;
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int i;
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if (!boot_cpu_has(X86_FEATURE_MWAIT))
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return;
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if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
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return;
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cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
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if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
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!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
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return;
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edx >>= MWAIT_SUBSTATE_SIZE;
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for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
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if (edx & MWAIT_SUBSTATE_MASK) {
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highest_cstate = i;
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highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
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}
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}
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power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
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(highest_subcstate - 1);
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#if defined(CONFIG_X86)
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switch (boot_cpu_data.x86_vendor) {
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case X86_VENDOR_AMD:
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case X86_VENDOR_INTEL:
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/*
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* AMD Fam10h TSC will tick in all
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* C/P/S0/S1 states when this bit is set.
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*/
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if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
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tsc_detected_unstable = 1;
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if (!boot_cpu_has(X86_FEATURE_ARAT))
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lapic_detected_unstable = 1;
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break;
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default:
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/* TSC & LAPIC could halt in idle */
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tsc_detected_unstable = 1;
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lapic_detected_unstable = 1;
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}
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#endif
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}
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static unsigned long cpu_weight[NR_CPUS];
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static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
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static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
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static void round_robin_cpu(unsigned int tsk_index)
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{
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struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
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cpumask_var_t tmp;
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int cpu;
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unsigned long min_weight = -1;
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unsigned long uninitialized_var(preferred_cpu);
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if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
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return;
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mutex_lock(&isolated_cpus_lock);
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cpumask_clear(tmp);
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for_each_cpu(cpu, pad_busy_cpus)
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cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
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cpumask_andnot(tmp, cpu_online_mask, tmp);
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/* avoid HT sibilings if possible */
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if (cpumask_empty(tmp))
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cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
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if (cpumask_empty(tmp)) {
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mutex_unlock(&isolated_cpus_lock);
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return;
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}
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for_each_cpu(cpu, tmp) {
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if (cpu_weight[cpu] < min_weight) {
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min_weight = cpu_weight[cpu];
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preferred_cpu = cpu;
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}
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}
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if (tsk_in_cpu[tsk_index] != -1)
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cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
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tsk_in_cpu[tsk_index] = preferred_cpu;
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cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
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cpu_weight[preferred_cpu]++;
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mutex_unlock(&isolated_cpus_lock);
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set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
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}
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static void exit_round_robin(unsigned int tsk_index)
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{
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struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
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cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
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tsk_in_cpu[tsk_index] = -1;
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}
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static unsigned int idle_pct = 5; /* percentage */
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static unsigned int round_robin_time = 10; /* second */
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static int power_saving_thread(void *data)
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{
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struct sched_param param = {.sched_priority = 1};
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int do_sleep;
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unsigned int tsk_index = (unsigned long)data;
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u64 last_jiffies = 0;
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sched_setscheduler(current, SCHED_RR, ¶m);
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while (!kthread_should_stop()) {
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int cpu;
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u64 expire_time;
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try_to_freeze();
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/* round robin to cpus */
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if (last_jiffies + round_robin_time * HZ < jiffies) {
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last_jiffies = jiffies;
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round_robin_cpu(tsk_index);
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}
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do_sleep = 0;
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expire_time = jiffies + HZ * (100 - idle_pct) / 100;
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while (!need_resched()) {
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if (tsc_detected_unstable && !tsc_marked_unstable) {
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/* TSC could halt in idle, so notify users */
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mark_tsc_unstable("TSC halts in idle");
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tsc_marked_unstable = 1;
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}
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if (lapic_detected_unstable && !lapic_marked_unstable) {
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int i;
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/* LAPIC could halt in idle, so notify users */
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for_each_online_cpu(i)
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clockevents_notify(
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CLOCK_EVT_NOTIFY_BROADCAST_ON,
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&i);
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lapic_marked_unstable = 1;
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}
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local_irq_disable();
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cpu = smp_processor_id();
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if (lapic_marked_unstable)
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clockevents_notify(
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CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
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stop_critical_timings();
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__monitor((void *)¤t_thread_info()->flags, 0, 0);
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smp_mb();
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if (!need_resched())
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__mwait(power_saving_mwait_eax, 1);
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start_critical_timings();
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if (lapic_marked_unstable)
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clockevents_notify(
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CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
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local_irq_enable();
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if (jiffies > expire_time) {
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do_sleep = 1;
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break;
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}
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}
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/*
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* current sched_rt has threshold for rt task running time.
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* When a rt task uses 95% CPU time, the rt thread will be
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* scheduled out for 5% CPU time to not starve other tasks. But
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* the mechanism only works when all CPUs have RT task running,
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* as if one CPU hasn't RT task, RT task from other CPUs will
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* borrow CPU time from this CPU and cause RT task use > 95%
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* CPU time. To make 'avoid starvation' work, takes a nap here.
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*/
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if (do_sleep)
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schedule_timeout_killable(HZ * idle_pct / 100);
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}
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exit_round_robin(tsk_index);
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return 0;
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}
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static struct task_struct *ps_tsks[NR_CPUS];
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static unsigned int ps_tsk_num;
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static int create_power_saving_task(void)
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{
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int rc = -ENOMEM;
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ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
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(void *)(unsigned long)ps_tsk_num,
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"power_saving/%d", ps_tsk_num);
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rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
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if (!rc)
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ps_tsk_num++;
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else
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ps_tsks[ps_tsk_num] = NULL;
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return rc;
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}
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static void destroy_power_saving_task(void)
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{
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if (ps_tsk_num > 0) {
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ps_tsk_num--;
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kthread_stop(ps_tsks[ps_tsk_num]);
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ps_tsks[ps_tsk_num] = NULL;
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}
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}
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static void set_power_saving_task_num(unsigned int num)
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{
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if (num > ps_tsk_num) {
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while (ps_tsk_num < num) {
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if (create_power_saving_task())
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return;
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}
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} else if (num < ps_tsk_num) {
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while (ps_tsk_num > num)
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destroy_power_saving_task();
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}
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}
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static void acpi_pad_idle_cpus(unsigned int num_cpus)
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{
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get_online_cpus();
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num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
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set_power_saving_task_num(num_cpus);
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put_online_cpus();
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}
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static uint32_t acpi_pad_idle_cpus_num(void)
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{
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return ps_tsk_num;
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}
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static ssize_t acpi_pad_rrtime_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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unsigned long num;
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if (strict_strtoul(buf, 0, &num))
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return -EINVAL;
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if (num < 1 || num >= 100)
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return -EINVAL;
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mutex_lock(&isolated_cpus_lock);
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round_robin_time = num;
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mutex_unlock(&isolated_cpus_lock);
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return count;
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}
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static ssize_t acpi_pad_rrtime_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
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}
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static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
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acpi_pad_rrtime_show,
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acpi_pad_rrtime_store);
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static ssize_t acpi_pad_idlepct_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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unsigned long num;
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if (strict_strtoul(buf, 0, &num))
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return -EINVAL;
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if (num < 1 || num >= 100)
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return -EINVAL;
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mutex_lock(&isolated_cpus_lock);
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idle_pct = num;
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mutex_unlock(&isolated_cpus_lock);
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return count;
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}
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static ssize_t acpi_pad_idlepct_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
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}
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static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
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acpi_pad_idlepct_show,
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acpi_pad_idlepct_store);
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static ssize_t acpi_pad_idlecpus_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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unsigned long num;
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if (strict_strtoul(buf, 0, &num))
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return -EINVAL;
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mutex_lock(&isolated_cpus_lock);
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acpi_pad_idle_cpus(num);
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mutex_unlock(&isolated_cpus_lock);
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return count;
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}
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static ssize_t acpi_pad_idlecpus_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return cpumask_scnprintf(buf, PAGE_SIZE,
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to_cpumask(pad_busy_cpus_bits));
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}
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static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
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acpi_pad_idlecpus_show,
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acpi_pad_idlecpus_store);
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static int acpi_pad_add_sysfs(struct acpi_device *device)
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{
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int result;
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result = device_create_file(&device->dev, &dev_attr_idlecpus);
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if (result)
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return -ENODEV;
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result = device_create_file(&device->dev, &dev_attr_idlepct);
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if (result) {
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device_remove_file(&device->dev, &dev_attr_idlecpus);
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return -ENODEV;
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}
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result = device_create_file(&device->dev, &dev_attr_rrtime);
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if (result) {
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device_remove_file(&device->dev, &dev_attr_idlecpus);
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device_remove_file(&device->dev, &dev_attr_idlepct);
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return -ENODEV;
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}
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return 0;
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}
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static void acpi_pad_remove_sysfs(struct acpi_device *device)
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{
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device_remove_file(&device->dev, &dev_attr_idlecpus);
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device_remove_file(&device->dev, &dev_attr_idlepct);
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device_remove_file(&device->dev, &dev_attr_rrtime);
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}
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/* Query firmware how many CPUs should be idle */
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static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
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{
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struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
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union acpi_object *package;
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int rev, num, ret = -EINVAL;
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if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
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return -EINVAL;
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if (!buffer.length || !buffer.pointer)
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return -EINVAL;
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package = buffer.pointer;
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if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
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goto out;
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rev = package->package.elements[0].integer.value;
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num = package->package.elements[1].integer.value;
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if (rev != 1 || num < 0)
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goto out;
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*num_cpus = num;
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ret = 0;
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out:
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kfree(buffer.pointer);
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return ret;
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}
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/* Notify firmware how many CPUs are idle */
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static void acpi_pad_ost(acpi_handle handle, int stat,
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uint32_t idle_cpus)
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{
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union acpi_object params[3] = {
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{.type = ACPI_TYPE_INTEGER,},
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{.type = ACPI_TYPE_INTEGER,},
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{.type = ACPI_TYPE_BUFFER,},
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};
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struct acpi_object_list arg_list = {3, params};
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params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
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params[1].integer.value = stat;
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params[2].buffer.length = 4;
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params[2].buffer.pointer = (void *)&idle_cpus;
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acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
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}
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static void acpi_pad_handle_notify(acpi_handle handle)
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{
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int num_cpus;
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uint32_t idle_cpus;
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mutex_lock(&isolated_cpus_lock);
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if (acpi_pad_pur(handle, &num_cpus)) {
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mutex_unlock(&isolated_cpus_lock);
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return;
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}
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acpi_pad_idle_cpus(num_cpus);
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idle_cpus = acpi_pad_idle_cpus_num();
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acpi_pad_ost(handle, 0, idle_cpus);
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mutex_unlock(&isolated_cpus_lock);
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}
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static void acpi_pad_notify(acpi_handle handle, u32 event,
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void *data)
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{
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struct acpi_device *device = data;
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switch (event) {
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case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
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acpi_pad_handle_notify(handle);
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acpi_bus_generate_proc_event(device, event, 0);
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acpi_bus_generate_netlink_event(device->pnp.device_class,
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dev_name(&device->dev), event, 0);
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break;
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default:
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printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
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break;
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}
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}
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static int acpi_pad_add(struct acpi_device *device)
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{
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acpi_status status;
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strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
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strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
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if (acpi_pad_add_sysfs(device))
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return -ENODEV;
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status = acpi_install_notify_handler(device->handle,
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ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
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if (ACPI_FAILURE(status)) {
|
|
acpi_pad_remove_sysfs(device);
|
|
return -ENODEV;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int acpi_pad_remove(struct acpi_device *device,
|
|
int type)
|
|
{
|
|
mutex_lock(&isolated_cpus_lock);
|
|
acpi_pad_idle_cpus(0);
|
|
mutex_unlock(&isolated_cpus_lock);
|
|
|
|
acpi_remove_notify_handler(device->handle,
|
|
ACPI_DEVICE_NOTIFY, acpi_pad_notify);
|
|
acpi_pad_remove_sysfs(device);
|
|
return 0;
|
|
}
|
|
|
|
static const struct acpi_device_id pad_device_ids[] = {
|
|
{"ACPI000C", 0},
|
|
{"", 0},
|
|
};
|
|
MODULE_DEVICE_TABLE(acpi, pad_device_ids);
|
|
|
|
static struct acpi_driver acpi_pad_driver = {
|
|
.name = "processor_aggregator",
|
|
.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
|
|
.ids = pad_device_ids,
|
|
.ops = {
|
|
.add = acpi_pad_add,
|
|
.remove = acpi_pad_remove,
|
|
},
|
|
};
|
|
|
|
static int __init acpi_pad_init(void)
|
|
{
|
|
power_saving_mwait_init();
|
|
if (power_saving_mwait_eax == 0)
|
|
return -EINVAL;
|
|
|
|
return acpi_bus_register_driver(&acpi_pad_driver);
|
|
}
|
|
|
|
static void __exit acpi_pad_exit(void)
|
|
{
|
|
acpi_bus_unregister_driver(&acpi_pad_driver);
|
|
}
|
|
|
|
module_init(acpi_pad_init);
|
|
module_exit(acpi_pad_exit);
|
|
MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
|
|
MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
|
|
MODULE_LICENSE("GPL");
|