[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>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/asm-ppc/smp.h b/include/asm-ppc/smp.h
index 17530c232c76..829481c0a9dc 100644
--- a/include/asm-ppc/smp.h
+++ b/include/asm-ppc/smp.h
@@ -41,6 +41,10 @@ extern void smp_send_xmon_break(int cpu);
 struct pt_regs;
 extern void smp_message_recv(int, struct pt_regs *);
 
+extern int __cpu_disable(void);
+extern void __cpu_die(unsigned int cpu);
+extern void cpu_die(void) __attribute__((noreturn));
+
 #define NO_PROC_ID              0xFF            /* No processor magic marker */
 #define PROC_CHANGE_PENALTY     20
 
@@ -64,6 +68,8 @@ extern struct klock_info_struct klock_info;
 
 #else /* !(CONFIG_SMP) */
 
+static inline void cpu_die(void) { }
+
 #endif /* !(CONFIG_SMP) */
 
 #endif /* !(_PPC_SMP_H) */