[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>
diff --git a/arch/ppc/platforms/pmac_smp.c b/arch/ppc/platforms/pmac_smp.c
index 8e049da..794a239 100644
--- a/arch/ppc/platforms/pmac_smp.c
+++ b/arch/ppc/platforms/pmac_smp.c
@@ -33,6 +33,7 @@
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
+#include <linux/cpu.h>
#include <asm/ptrace.h>
#include <asm/atomic.h>
@@ -55,9 +56,7 @@
* Powersurge (old powermac SMP) support.
*/
-extern void __secondary_start_psurge(void);
-extern void __secondary_start_psurge2(void); /* Temporary horrible hack */
-extern void __secondary_start_psurge3(void); /* Temporary horrible hack */
+extern void __secondary_start_pmac_0(void);
/* Addresses for powersurge registers */
#define HAMMERHEAD_BASE 0xf8000000
@@ -119,7 +118,7 @@
static unsigned int pri_tb_hi, pri_tb_lo;
static unsigned int pri_tb_stamp;
-static void __init core99_init_caches(int cpu)
+static void __devinit core99_init_caches(int cpu)
{
if (!cpu_has_feature(CPU_FTR_L2CR))
return;
@@ -346,7 +345,7 @@
static void __init smp_psurge_kick_cpu(int nr)
{
- void (*start)(void) = __secondary_start_psurge;
+ unsigned long start = __pa(__secondary_start_pmac_0) + nr * 8;
unsigned long a;
/* may need to flush here if secondary bats aren't setup */
@@ -356,17 +355,7 @@
if (ppc_md.progress) ppc_md.progress("smp_psurge_kick_cpu", 0x353);
- /* setup entry point of secondary processor */
- switch (nr) {
- case 2:
- start = __secondary_start_psurge2;
- break;
- case 3:
- start = __secondary_start_psurge3;
- break;
- }
-
- out_be32(psurge_start, __pa(start));
+ out_be32(psurge_start, start);
mb();
psurge_set_ipi(nr);
@@ -500,14 +489,14 @@
return ncpus;
}
-static void __init smp_core99_kick_cpu(int nr)
+static void __devinit smp_core99_kick_cpu(int nr)
{
unsigned long save_vector, new_vector;
unsigned long flags;
volatile unsigned long *vector
= ((volatile unsigned long *)(KERNELBASE+0x100));
- if (nr < 1 || nr > 3)
+ if (nr < 0 || nr > 3)
return;
if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu", 0x346);
@@ -518,19 +507,9 @@
save_vector = *vector;
/* Setup fake reset vector that does
- * b __secondary_start_psurge - KERNELBASE
+ * b __secondary_start_pmac_0 + nr*8 - KERNELBASE
*/
- switch(nr) {
- case 1:
- new_vector = (unsigned long)__secondary_start_psurge;
- break;
- case 2:
- new_vector = (unsigned long)__secondary_start_psurge2;
- break;
- case 3:
- new_vector = (unsigned long)__secondary_start_psurge3;
- break;
- }
+ new_vector = (unsigned long) __secondary_start_pmac_0 + nr * 8;
*vector = 0x48000002 + new_vector - KERNELBASE;
/* flush data cache and inval instruction cache */
@@ -554,7 +533,7 @@
if (ppc_md.progress) ppc_md.progress("smp_core99_kick_cpu done", 0x347);
}
-static void __init smp_core99_setup_cpu(int cpu_nr)
+static void __devinit smp_core99_setup_cpu(int cpu_nr)
{
/* Setup L2/L3 */
if (cpu_nr != 0)
@@ -668,3 +647,47 @@
.give_timebase = smp_core99_give_timebase,
.take_timebase = smp_core99_take_timebase,
};
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+int __cpu_disable(void)
+{
+ cpu_clear(smp_processor_id(), cpu_online_map);
+
+ /* XXX reset cpu affinity here */
+ openpic_set_priority(0xf);
+ asm volatile("mtdec %0" : : "r" (0x7fffffff));
+ mb();
+ udelay(20);
+ asm volatile("mtdec %0" : : "r" (0x7fffffff));
+ return 0;
+}
+
+extern void low_cpu_die(void) __attribute__((noreturn)); /* in pmac_sleep.S */
+static int cpu_dead[NR_CPUS];
+
+void cpu_die(void)
+{
+ local_irq_disable();
+ cpu_dead[smp_processor_id()] = 1;
+ mb();
+ low_cpu_die();
+}
+
+void __cpu_die(unsigned int cpu)
+{
+ int timeout;
+
+ timeout = 1000;
+ while (!cpu_dead[cpu]) {
+ if (--timeout == 0) {
+ printk("CPU %u refused to die!\n", cpu);
+ break;
+ }
+ msleep(1);
+ }
+ cpu_callin_map[cpu] = 0;
+ cpu_dead[cpu] = 0;
+}
+
+#endif