linux/arch/ppc/kernel/idle.c
Paul Mackerras 31139971b3 [PATCH] ppc32: support hotplug cpu on powermacs
This allows cpus to be off-lined on 32-bit SMP powermacs.  When a cpu
is off-lined, it is put into sleep mode with interrupts disabled.  It
can be on-lined again by asserting its soft-reset pin, which is
connected to a GPIO pin.

With this I can off-line the second cpu in my dual G4 powermac, which
means that I can then suspend the machine (the suspend/resume code
refuses to suspend if more than one cpu is online, and making it cope
with multiple cpus is surprisingly messy).

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 10:15:11 -07:00

105 lines
2.3 KiB
C

/*
* Idle daemon for PowerPC. Idle daemon will handle any action
* that needs to be taken when the system becomes idle.
*
* Written by Cort Dougan (cort@cs.nmt.edu). Subsequently hacked
* on by Tom Rini, Armin Kuster, Paul Mackerras and others.
*
* 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/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/mmu.h>
#include <asm/cache.h>
#include <asm/cputable.h>
#include <asm/machdep.h>
void default_idle(void)
{
void (*powersave)(void);
int cpu = smp_processor_id();
powersave = ppc_md.power_save;
if (!need_resched()) {
if (powersave != NULL)
powersave();
#ifdef CONFIG_SMP
else {
set_thread_flag(TIF_POLLING_NRFLAG);
while (!need_resched() && !cpu_is_offline(cpu))
barrier();
clear_thread_flag(TIF_POLLING_NRFLAG);
}
#endif
}
if (need_resched())
schedule();
if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
cpu_die();
}
/*
* The body of the idle task.
*/
void cpu_idle(void)
{
for (;;)
if (ppc_md.idle != NULL)
ppc_md.idle();
else
default_idle();
}
#if defined(CONFIG_SYSCTL) && defined(CONFIG_6xx)
/*
* Register the sysctl to set/clear powersave_nap.
*/
extern unsigned long 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