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authorPaul Mackerras <paulus@samba.org>2005-09-10 21:13:13 +1000
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-10 10:15:11 -0700
commit31139971b3dc9fbb2e8a8572fb81e6e8470f363a (patch)
tree644fc6833fe6e18d00dbc8b6b281f77e7b923d35 /arch/ppc/kernel/idle.c
parentbb0bb3b6596cdb08adb0b72453cc67d48e139c2c (diff)
[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>
Diffstat (limited to 'arch/ppc/kernel/idle.c')
-rw-r--r--arch/ppc/kernel/idle.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/ppc/kernel/idle.c b/arch/ppc/kernel/idle.c
index 53547b6de45b..fba29c876b62 100644
--- a/arch/ppc/kernel/idle.c
+++ b/arch/ppc/kernel/idle.c
@@ -22,6 +22,7 @@
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
+#include <linux/cpu.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
@@ -35,6 +36,7 @@
void default_idle(void)
{
void (*powersave)(void);
+ int cpu = smp_processor_id();
powersave = ppc_md.power_save;
@@ -44,7 +46,7 @@ void default_idle(void)
#ifdef CONFIG_SMP
else {
set_thread_flag(TIF_POLLING_NRFLAG);
- while (!need_resched())
+ while (!need_resched() && !cpu_is_offline(cpu))
barrier();
clear_thread_flag(TIF_POLLING_NRFLAG);
}
@@ -52,6 +54,8 @@ void default_idle(void)
}
if (need_resched())
schedule();
+ if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
+ cpu_die();
}
/*