[POWERPC] Only enable cpu hotplug via RTAS if the required firmware support is found

To support cpu hotplug on pseries we require two RTAS tokens.  The cpu
hotplug machinery should only be wired up if these tokens are found in
the device tree.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 11 insertions, 6 deletions

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 12864d75126d..e78e8ac95550 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -64,6 +64,8 @@ static void pSeries_mach_cpu_die(void)
         for(;;);
 }
 
+static int qcss_tok;    /* query-cpu-stopped-state token */
+
 /* Get state of physical CPU.
  * Return codes:
  *      0       - The processor is in the RTAS stopped state
@@ -74,12 +76,8 @@ static void pSeries_mach_cpu_die(void)
  */
 static int query_cpu_stopped(unsigned int pcpu)
 {
-        int cpu_status;
-        int status, qcss_tok;
+        int cpu_status, status;
 
-        qcss_tok = rtas_token("query-cpu-stopped-state");
-        if (qcss_tok == RTAS_UNKNOWN_SERVICE)
-                return -1;
         status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
         if (status != 0) {
                 printk(KERN_ERR
@@ -254,9 +252,16 @@ static struct notifier_block pSeries_smp_nb = {
 static int __init pseries_cpu_hotplug_init(void)
 {
         rtas_stop_self_args.token = rtas_token("stop-self");
+        qcss_tok = rtas_token("query-cpu-stopped-state");
 
-        ppc_md.cpu_die = pSeries_mach_cpu_die;
+        if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE ||
+                        qcss_tok == RTAS_UNKNOWN_SERVICE) {
+                printk(KERN_INFO "CPU Hotplug not supported by firmware "
+                                "- disabling.\n");
+                return 0;
+        }
 
+        ppc_md.cpu_die = pSeries_mach_cpu_die;
         smp_ops->cpu_disable = pSeries_cpu_disable;
         smp_ops->cpu_die = pSeries_cpu_die;