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380 lines
8.2 KiB
380 lines
8.2 KiB
/*
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* Idle daemon for PowerPC. Idle daemon will handle any action
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* that needs to be taken when the system becomes idle.
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*
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* Originally Written by Cort Dougan (cort@cs.nmt.edu)
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*
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* iSeries supported added by Mike Corrigan <mikejc@us.ibm.com>
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*
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* Additional shared processor, SMT, and firmware support
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* Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/sysctl.h>
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#include <linux/smp.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <asm/mmu.h>
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#include <asm/cputable.h>
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#include <asm/time.h>
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#include <asm/iSeries/HvCall.h>
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#include <asm/iSeries/ItLpQueue.h>
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#include <asm/plpar_wrappers.h>
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#include <asm/systemcfg.h>
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extern void power4_idle(void);
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static int (*idle_loop)(void);
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#ifdef CONFIG_PPC_ISERIES
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static unsigned long maxYieldTime = 0;
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static unsigned long minYieldTime = 0xffffffffffffffffUL;
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static void yield_shared_processor(void)
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{
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unsigned long tb;
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unsigned long yieldTime;
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HvCall_setEnabledInterrupts(HvCall_MaskIPI |
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HvCall_MaskLpEvent |
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HvCall_MaskLpProd |
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HvCall_MaskTimeout);
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tb = get_tb();
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/* Compute future tb value when yield should expire */
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HvCall_yieldProcessor(HvCall_YieldTimed, tb+tb_ticks_per_jiffy);
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yieldTime = get_tb() - tb;
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if (yieldTime > maxYieldTime)
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maxYieldTime = yieldTime;
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if (yieldTime < minYieldTime)
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minYieldTime = yieldTime;
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/*
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* The decrementer stops during the yield. Force a fake decrementer
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* here and let the timer_interrupt code sort out the actual time.
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*/
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get_paca()->lppaca.int_dword.fields.decr_int = 1;
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process_iSeries_events();
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}
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static int iSeries_idle(void)
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{
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struct paca_struct *lpaca;
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long oldval;
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unsigned long CTRL;
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/* ensure iSeries run light will be out when idle */
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clear_thread_flag(TIF_RUN_LIGHT);
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CTRL = mfspr(CTRLF);
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CTRL &= ~RUNLATCH;
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mtspr(CTRLT, CTRL);
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lpaca = get_paca();
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while (1) {
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if (lpaca->lppaca.shared_proc) {
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if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
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process_iSeries_events();
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if (!need_resched())
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yield_shared_processor();
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} else {
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oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
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if (!oldval) {
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set_thread_flag(TIF_POLLING_NRFLAG);
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while (!need_resched()) {
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HMT_medium();
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if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
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process_iSeries_events();
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HMT_low();
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}
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HMT_medium();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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} else {
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set_need_resched();
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}
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}
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schedule();
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}
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return 0;
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}
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#else
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static int default_idle(void)
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{
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long oldval;
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unsigned int cpu = smp_processor_id();
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while (1) {
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oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
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if (!oldval) {
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set_thread_flag(TIF_POLLING_NRFLAG);
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while (!need_resched() && !cpu_is_offline(cpu)) {
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barrier();
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/*
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* Go into low thread priority and possibly
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* low power mode.
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*/
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HMT_low();
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HMT_very_low();
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}
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HMT_medium();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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} else {
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set_need_resched();
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}
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schedule();
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if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
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cpu_die();
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}
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return 0;
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}
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#ifdef CONFIG_PPC_PSERIES
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DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
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int dedicated_idle(void)
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{
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long oldval;
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struct paca_struct *lpaca = get_paca(), *ppaca;
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unsigned long start_snooze;
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unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
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unsigned int cpu = smp_processor_id();
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ppaca = &paca[cpu ^ 1];
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while (1) {
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/*
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* Indicate to the HV that we are idle. Now would be
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* a good time to find other work to dispatch.
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*/
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lpaca->lppaca.idle = 1;
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oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
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if (!oldval) {
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set_thread_flag(TIF_POLLING_NRFLAG);
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start_snooze = __get_tb() +
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*smt_snooze_delay * tb_ticks_per_usec;
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while (!need_resched() && !cpu_is_offline(cpu)) {
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/*
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* Go into low thread priority and possibly
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* low power mode.
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*/
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HMT_low();
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HMT_very_low();
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if (*smt_snooze_delay == 0 ||
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__get_tb() < start_snooze)
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continue;
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HMT_medium();
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if (!(ppaca->lppaca.idle)) {
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local_irq_disable();
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/*
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* We are about to sleep the thread
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* and so wont be polling any
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* more.
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*/
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clear_thread_flag(TIF_POLLING_NRFLAG);
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/*
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* SMT dynamic mode. Cede will result
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* in this thread going dormant, if the
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* partner thread is still doing work.
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* Thread wakes up if partner goes idle,
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* an interrupt is presented, or a prod
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* occurs. Returning from the cede
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* enables external interrupts.
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*/
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if (!need_resched())
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cede_processor();
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else
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local_irq_enable();
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} else {
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/*
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* Give the HV an opportunity at the
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* processor, since we are not doing
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* any work.
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*/
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poll_pending();
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}
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}
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clear_thread_flag(TIF_POLLING_NRFLAG);
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} else {
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set_need_resched();
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}
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HMT_medium();
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lpaca->lppaca.idle = 0;
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schedule();
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if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
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cpu_die();
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}
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return 0;
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}
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static int shared_idle(void)
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{
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struct paca_struct *lpaca = get_paca();
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unsigned int cpu = smp_processor_id();
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while (1) {
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/*
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* Indicate to the HV that we are idle. Now would be
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* a good time to find other work to dispatch.
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*/
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lpaca->lppaca.idle = 1;
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while (!need_resched() && !cpu_is_offline(cpu)) {
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local_irq_disable();
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/*
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* Yield the processor to the hypervisor. We return if
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* an external interrupt occurs (which are driven prior
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* to returning here) or if a prod occurs from another
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* processor. When returning here, external interrupts
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* are enabled.
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*
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* Check need_resched() again with interrupts disabled
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* to avoid a race.
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*/
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if (!need_resched())
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cede_processor();
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else
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local_irq_enable();
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}
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HMT_medium();
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lpaca->lppaca.idle = 0;
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schedule();
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if (cpu_is_offline(smp_processor_id()) &&
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system_state == SYSTEM_RUNNING)
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cpu_die();
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}
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return 0;
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}
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#endif /* CONFIG_PPC_PSERIES */
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static int native_idle(void)
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{
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while(1) {
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/* check CPU type here */
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if (!need_resched())
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power4_idle();
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if (need_resched())
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schedule();
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if (cpu_is_offline(_smp_processor_id()) &&
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system_state == SYSTEM_RUNNING)
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cpu_die();
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}
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return 0;
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}
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#endif /* CONFIG_PPC_ISERIES */
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void cpu_idle(void)
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{
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idle_loop();
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}
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int powersave_nap;
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#ifdef CONFIG_SYSCTL
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/*
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* Register the sysctl to set/clear powersave_nap.
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*/
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static ctl_table powersave_nap_ctl_table[]={
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{
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.ctl_name = KERN_PPC_POWERSAVE_NAP,
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.procname = "powersave-nap",
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.data = &powersave_nap,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{ 0, },
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};
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static ctl_table powersave_nap_sysctl_root[] = {
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{ 1, "kernel", NULL, 0, 0755, powersave_nap_ctl_table, },
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{ 0,},
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};
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static int __init
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register_powersave_nap_sysctl(void)
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{
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register_sysctl_table(powersave_nap_sysctl_root, 0);
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return 0;
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}
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__initcall(register_powersave_nap_sysctl);
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#endif
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int idle_setup(void)
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{
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/*
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* Move that junk to each platform specific file, eventually define
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* a pSeries_idle for shared processor stuff
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*/
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#ifdef CONFIG_PPC_ISERIES
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idle_loop = iSeries_idle;
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return 1;
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#else
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idle_loop = default_idle;
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#endif
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#ifdef CONFIG_PPC_PSERIES
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if (systemcfg->platform & PLATFORM_PSERIES) {
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if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
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if (get_paca()->lppaca.shared_proc) {
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printk(KERN_INFO "Using shared processor idle loop\n");
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idle_loop = shared_idle;
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} else {
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printk(KERN_INFO "Using dedicated idle loop\n");
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idle_loop = dedicated_idle;
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}
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} else {
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printk(KERN_INFO "Using default idle loop\n");
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idle_loop = default_idle;
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}
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}
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#endif /* CONFIG_PPC_PSERIES */
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#ifndef CONFIG_PPC_ISERIES
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if (systemcfg->platform == PLATFORM_POWERMAC ||
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systemcfg->platform == PLATFORM_MAPLE) {
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printk(KERN_INFO "Using native/NAP idle loop\n");
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idle_loop = native_idle;
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}
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#endif /* CONFIG_PPC_ISERIES */
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return 1;
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}
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