1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Idle daemon for PowerPC. Idle daemon will handle any action 4 * that needs to be taken when the system becomes idle. 5 * 6 * Originally written by Cort Dougan (cort@cs.nmt.edu). 7 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster, 8 * Paul Mackerras and others. 9 * 10 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com> 11 * 12 * Additional shared processor, SMT, and firmware support 13 * Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com> 14 * 15 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org> 16 */ 17 18#include <linux/sched.h> 19#include <linux/kernel.h> 20#include <linux/smp.h> 21#include <linux/cpu.h> 22#include <linux/sysctl.h> 23#include <linux/tick.h> 24 25#include <asm/processor.h> 26#include <asm/cputable.h> 27#include <asm/time.h> 28#include <asm/machdep.h> 29#include <asm/runlatch.h> 30#include <asm/smp.h> 31 32 33unsigned long cpuidle_disable = IDLE_NO_OVERRIDE; 34EXPORT_SYMBOL(cpuidle_disable); 35 36static int __init powersave_off(char *arg) 37{ 38 ppc_md.power_save = NULL; 39 cpuidle_disable = IDLE_POWERSAVE_OFF; 40 return 1; 41} 42__setup("powersave=off", powersave_off); 43 44void arch_cpu_idle(void) 45{ 46 ppc64_runlatch_off(); 47 48 if (ppc_md.power_save) { 49 ppc_md.power_save(); 50 /* 51 * Some power_save functions return with 52 * interrupts enabled, some don't. 53 */ 54 if (!irqs_disabled()) 55 raw_local_irq_disable(); 56 } else { 57 /* 58 * Go into low thread priority and possibly 59 * low power mode. 60 */ 61 HMT_low(); 62 HMT_very_low(); 63 } 64 65 HMT_medium(); 66 ppc64_runlatch_on(); 67} 68 69int powersave_nap; 70 71#ifdef CONFIG_PPC_970_NAP 72void power4_idle(void) 73{ 74 if (!cpu_has_feature(CPU_FTR_CAN_NAP)) 75 return; 76 77 if (!powersave_nap) 78 return; 79 80 if (!prep_irq_for_idle()) 81 return; 82 83 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 84 asm volatile(PPC_DSSALL " ; sync" ::: "memory"); 85 86 power4_idle_nap(); 87 88 /* 89 * power4_idle_nap returns with interrupts enabled (soft and hard). 90 * to our caller with interrupts enabled (soft and hard). Our caller 91 * can cope with either interrupts disabled or enabled upon return. 92 */ 93} 94#endif 95 96#ifdef CONFIG_SYSCTL 97/* 98 * Register the sysctl to set/clear powersave_nap. 99 */ 100static struct ctl_table powersave_nap_ctl_table[] = { 101 { 102 .procname = "powersave-nap", 103 .data = &powersave_nap, 104 .maxlen = sizeof(int), 105 .mode = 0644, 106 .proc_handler = proc_dointvec, 107 }, 108}; 109 110static int __init 111register_powersave_nap_sysctl(void) 112{ 113 register_sysctl("kernel", powersave_nap_ctl_table); 114 115 return 0; 116} 117__initcall(register_powersave_nap_sysctl); 118#endif 119