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author | Paul Mackerras <paulus@samba.org> | 2006-03-27 15:03:03 +1100 |
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committer | Paul Mackerras <paulus@samba.org> | 2006-03-27 15:03:03 +1100 |
commit | a0652fc9a28c3ef8cd59264bfcb089c44d1b0e06 (patch) | |
tree | a28527b65237b3067553a993f5ad06dfb24df044 /arch/powerpc/kernel/idle.c | |
parent | 55aab8cd3a498201b769a19de861c77516bdfd45 (diff) | |
download | kernel_samsung_crespo-a0652fc9a28c3ef8cd59264bfcb089c44d1b0e06.zip kernel_samsung_crespo-a0652fc9a28c3ef8cd59264bfcb089c44d1b0e06.tar.gz kernel_samsung_crespo-a0652fc9a28c3ef8cd59264bfcb089c44d1b0e06.tar.bz2 |
powerpc: Unify the 32 and 64 bit idle loops
This unifies the 32-bit (ARCH=ppc and ARCH=powerpc) and 64-bit idle
loops. It brings over the concept of having a ppc_md.power_save
function from 32-bit to ARCH=powerpc, which lets us get rid of
native_idle(). With this we will also be able to simplify the idle
handling for pSeries and cell.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/idle.c')
-rw-r--r-- | arch/powerpc/kernel/idle.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c new file mode 100644 index 0000000..e9f321d --- /dev/null +++ b/arch/powerpc/kernel/idle.c @@ -0,0 +1,122 @@ +/* + * Idle daemon for PowerPC. Idle daemon will handle any action + * that needs to be taken when the system becomes idle. + * + * Originally written by Cort Dougan (cort@cs.nmt.edu). + * Subsequent 32-bit hacking by Tom Rini, Armin Kuster, + * Paul Mackerras and others. + * + * iSeries supported added by Mike Corrigan <mikejc@us.ibm.com> + * + * Additional shared processor, SMT, and firmware support + * Copyright (c) 2003 Dave Engebretsen <engebret@us.ibm.com> + * + * 32-bit and 64-bit versions merged by Paul Mackerras <paulus@samba.org> + * + * 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. + */ + +#include <linux/config.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/smp.h> +#include <linux/cpu.h> +#include <linux/sysctl.h> + +#include <asm/system.h> +#include <asm/processor.h> +#include <asm/cputable.h> +#include <asm/time.h> +#include <asm/machdep.h> +#include <asm/smp.h> + +#ifdef CONFIG_HOTPLUG_CPU +#define cpu_should_die() (cpu_is_offline(smp_processor_id()) && \ + system_state == SYSTEM_RUNNING) +#else +#define cpu_should_die() 0 +#endif + +/* + * The body of the idle task. + */ +void cpu_idle(void) +{ + if (ppc_md.idle_loop) + ppc_md.idle_loop(); /* doesn't return */ + + set_thread_flag(TIF_POLLING_NRFLAG); + while (1) { + ppc64_runlatch_off(); + + while (!need_resched() && !cpu_should_die()) { + if (ppc_md.power_save) { + clear_thread_flag(TIF_POLLING_NRFLAG); + /* + * smp_mb is so clearing of TIF_POLLING_NRFLAG + * is ordered w.r.t. need_resched() test. + */ + smp_mb(); + local_irq_disable(); + + /* check again after disabling irqs */ + if (!need_resched() && !cpu_should_die()) + ppc_md.power_save(); + + local_irq_enable(); + set_thread_flag(TIF_POLLING_NRFLAG); + + } else { + /* + * Go into low thread priority and possibly + * low power mode. + */ + HMT_low(); + HMT_very_low(); + } + } + + HMT_medium(); + ppc64_runlatch_on(); + if (cpu_should_die()) + cpu_die(); + preempt_enable_no_resched(); + schedule(); + preempt_disable(); + } +} + +int powersave_nap; + +#ifdef CONFIG_SYSCTL +/* + * Register the sysctl to set/clear powersave_nap. + */ +static ctl_table powersave_nap_ctl_table[]={ + { + .ctl_name = KERN_PPC_POWERSAVE_NAP, + .procname = "powersave-nap", + .data = &powersave_nap, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, + { 0, }, +}; +static ctl_table powersave_nap_sysctl_root[] = { + { 1, "kernel", NULL, 0, 0755, powersave_nap_ctl_table, }, + { 0,}, +}; + +static int __init +register_powersave_nap_sysctl(void) +{ + register_sysctl_table(powersave_nap_sysctl_root, 0); + + return 0; +} +__initcall(register_powersave_nap_sysctl); +#endif |