powerpc/xics: Factor out cpu joining/unjoining the GIQ

This factors out processors joining and unjoining the Global Interrupt
Queue into a separate function.

There is a bit of math to calculate the arguments to rtas to join
or leave the global interrupt queue, and a warning on failure
afterwards.  Make a helper for the 3 callers.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 13 insertions, 20 deletions

diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c
index 27327fc86055..0bb553331f4f 100644
--- a/arch/powerpc/platforms/pseries/xics.c
+++ b/arch/powerpc/platforms/pseries/xics.c
@@ -727,20 +727,19 @@ static void xics_set_cpu_priority(unsigned char cppr)
         iosync();
 }
 
+/* Have the calling processor join or leave the specified global queue */
+static void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
+{
+        int status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE,
+                (1UL << interrupt_server_size) - 1 - gserver, join);
+        WARN_ON(status < 0);
+}
 
 void xics_setup_cpu(void)
 {
         xics_set_cpu_priority(0xff);
 
-        /*
-         * Put the calling processor into the GIQ.  This is really only
-         * necessary from a secondary thread as the OF start-cpu interface
-         * performs this function for us on primary threads.
-         *
-         * XXX: undo of teardown on kexec needs this too, as may hotplug
-         */
-        rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE,
-                (1UL << interrupt_server_size) - 1 - default_distrib_server, 1);
+        xics_set_cpu_giq(default_distrib_server, 1);
 }
 
 void xics_teardown_cpu(void)
@@ -749,9 +748,7 @@ void xics_teardown_cpu(void)
 
         xics_set_cpu_priority(0);
 
-        /*
-         * Clear IPI
-         */
+        /* Clear any pending IPI request */
         if (firmware_has_feature(FW_FEATURE_LPAR))
                 lpar_qirr_info(cpu, 0xff);
         else
@@ -785,9 +782,7 @@ void xics_kexec_teardown_cpu(int secondary)
          * so leave the master cpu in the group.
          */
         if (secondary)
-                rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE,
-                                   (1UL << interrupt_server_size) - 1 -
-                                   default_distrib_server, 0);
+                xics_set_cpu_giq(default_distrib_server, 0);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -795,7 +790,6 @@ void xics_kexec_teardown_cpu(int secondary)
 /* Interrupts are disabled. */
 void xics_migrate_irqs_away(void)
 {
-        int status;
         int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
         unsigned int irq, virq;
 
@@ -806,10 +800,8 @@ void xics_migrate_irqs_away(void)
         /* Reject any interrupt that was queued to us... */
         xics_set_cpu_priority(0);
 
-        /* remove ourselves from the global interrupt queue */
-        status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE,
-                (1UL << interrupt_server_size) - 1 - default_distrib_server, 0);
-        WARN_ON(status < 0);
+        /* Remove ourselves from the global interrupt queue */
+        xics_set_cpu_giq(default_distrib_server, 0);
 
         /* Allow IPIs again... */
         xics_set_cpu_priority(DEFAULT_PRIORITY);
@@ -817,6 +809,7 @@ void xics_migrate_irqs_away(void)
         for_each_irq(virq) {
                 struct irq_desc *desc;
                 int xics_status[2];
+                int status;
                 unsigned long flags;
 
                 /* We cant set affinity on ISA interrupts */