[Blackfin] arch: initial generic time and clock sources

This patch enables Hight-Res Timers and tickless kernel

Signed-off-by: Vitja Makarov <vitja.makarov@gmail.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 28 insertions, 15 deletions

diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c
index 6b8459c66163..6dedb2da8b67 100644
--- a/arch/blackfin/kernel/process.c
+++ b/arch/blackfin/kernel/process.c
@@ -32,6 +32,8 @@
 #include <linux/unistd.h>
 #include <linux/user.h>
 #include <linux/uaccess.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
 #include <linux/fs.h>
 #include <linux/err.h>
 
@@ -69,33 +71,44 @@ EXPORT_SYMBOL(pm_power_off);
  * The idle loop on BFIN
  */
 #ifdef CONFIG_IDLE_L1
-void default_idle(void)__attribute__((l1_text));
+static void default_idle(void)__attribute__((l1_text));
 void cpu_idle(void)__attribute__((l1_text));
 #endif
 
-void default_idle(void)
+/*
+ * This is our default idle handler.  We need to disable
+ * interrupts here to ensure we don't miss a wakeup call.
+ */
+static void default_idle(void)
 {
-        while (!need_resched()) {
-                local_irq_disable();
-                if (likely(!need_resched()))
-                        idle_with_irq_disabled();
-                local_irq_enable();
-        }
-}
+        local_irq_disable();
+        if (!need_resched())
+                idle_with_irq_disabled();
 
-void (*idle)(void) = default_idle;
+        local_irq_enable();
+}
 
 /*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
+ * The idle thread.  We try to conserve power, while trying to keep
+ * overall latency low.  The architecture specific idle is passed
+ * a value to indicate the level of "idleness" of the system.
  */
 void cpu_idle(void)
 {
         /* endless idle loop with no priority at all */
         while (1) {
-                idle();
+                void (*idle)(void) = pm_idle;
+
+#ifdef CONFIG_HOTPLUG_CPU
+                if (cpu_is_offline(smp_processor_id()))
+                        cpu_die();
+#endif
+                if (!idle)
+                        idle = default_idle;
+                tick_nohz_stop_sched_tick();
+                while (!need_resched())
+                        idle();
+                tick_nohz_restart_sched_tick();
                 preempt_enable_no_resched();
                 schedule();
                 preempt_disable();