1 /* 2 * Idle daemon for PowerPC. Idle daemon will handle any action 3 * that needs to be taken when the system becomes idle. 4 * 5 * Originally written by Cort Dougan (cort@cs.nmt.edu). 6 * Subsequent 32-bit hacking by Tom Rini, Armin Kuster, 7 * Paul Mackerras and others. 8 * 9 * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com> 10 * 11 * Additional shared processor, SMT, and firmware support 12 * Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com> 13 * 14 * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org> 15 * 16 * This program is free software; you can redistribute it and/or 17 * modify it under the terms of the GNU General Public License 18 * as published by the Free Software Foundation; either version 19 * 2 of the License, or (at your option) any later version. 20 */ 21 22 #include <linux/sched.h> 23 #include <linux/kernel.h> 24 #include <linux/smp.h> 25 #include <linux/cpu.h> 26 #include <linux/sysctl.h> 27 #include <linux/tick.h> 28 29 #include <asm/processor.h> 30 #include <asm/cputable.h> 31 #include <asm/time.h> 32 #include <asm/machdep.h> 33 #include <asm/runlatch.h> 34 #include <asm/smp.h> 35 36 37 unsigned long cpuidle_disable = IDLE_NO_OVERRIDE; 38 EXPORT_SYMBOL(cpuidle_disable); 39 40 static int __init powersave_off(char *arg) 41 { 42 ppc_md.power_save = NULL; 43 cpuidle_disable = IDLE_POWERSAVE_OFF; 44 return 0; 45 } 46 __setup("powersave=off", powersave_off); 47 48 #ifdef CONFIG_HOTPLUG_CPU 49 void arch_cpu_idle_dead(void) 50 { 51 sched_preempt_enable_no_resched(); 52 cpu_die(); 53 } 54 #endif 55 56 void arch_cpu_idle(void) 57 { 58 ppc64_runlatch_off(); 59 60 if (ppc_md.power_save) { 61 ppc_md.power_save(); 62 /* 63 * Some power_save functions return with 64 * interrupts enabled, some don't. 65 */ 66 if (irqs_disabled()) 67 local_irq_enable(); 68 } else { 69 local_irq_enable(); 70 /* 71 * Go into low thread priority and possibly 72 * low power mode. 73 */ 74 HMT_low(); 75 HMT_very_low(); 76 } 77 78 HMT_medium(); 79 ppc64_runlatch_on(); 80 } 81 82 int powersave_nap; 83 84 #ifdef CONFIG_SYSCTL 85 /* 86 * Register the sysctl to set/clear powersave_nap. 87 */ 88 static struct ctl_table powersave_nap_ctl_table[] = { 89 { 90 .procname = "powersave-nap", 91 .data = &powersave_nap, 92 .maxlen = sizeof(int), 93 .mode = 0644, 94 .proc_handler = proc_dointvec, 95 }, 96 {} 97 }; 98 static struct ctl_table powersave_nap_sysctl_root[] = { 99 { 100 .procname = "kernel", 101 .mode = 0555, 102 .child = powersave_nap_ctl_table, 103 }, 104 {} 105 }; 106 107 static int __init 108 register_powersave_nap_sysctl(void) 109 { 110 register_sysctl_table(powersave_nap_sysctl_root); 111 112 return 0; 113 } 114 __initcall(register_powersave_nap_sysctl); 115 #endif 116