parisc: Enhance detection of synchronous cr16 clocksources

[sfrench/cifs-2.6.git] / arch / parisc / kernel / time.c

diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index 89421df70160833a84614c1336fee443ee9b5351..2d956aa0a38abbc3829757bab4749dd6a0037490 100644 (file)
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -243,14 +243,30 @@ void __init time_init(void)
 static int __init init_cr16_clocksource(void)
 {
        /*
-        * The cr16 interval timers are not syncronized across CPUs, so mark
-        * them unstable and lower rating on SMP systems.
+        * The cr16 interval timers are not syncronized across CPUs on
+        * different sockets, so mark them unstable and lower rating on
+        * multi-socket SMP systems.
         */
        if (num_online_cpus() > 1) {
-               clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
-               clocksource_cr16.rating = 0;
+               int cpu;
+               unsigned long cpu0_loc;
+               cpu0_loc = per_cpu(cpu_data, 0).cpu_loc;
+
+               for_each_online_cpu(cpu) {
+                       if (cpu0_loc == per_cpu(cpu_data, cpu).cpu_loc)
+                               continue;
+
+                       clocksource_cr16.name = "cr16_unstable";
+                       clocksource_cr16.flags = CLOCK_SOURCE_UNSTABLE;
+                       clocksource_cr16.rating = 0;
+                       break;
+               }
        }
 
+       /* XXX: We may want to mark sched_clock stable here if cr16 clocks are
+        *      in sync:
+        *      (clocksource_cr16.flags == CLOCK_SOURCE_IS_CONTINUOUS) */
+
        /* register at clocksource framework */
        clocksource_register_hz(&clocksource_cr16,
                100 * PAGE0->mem_10msec);