MN10300: And Panasonic AM34 subarch and implement SMP

Implement the Panasonic MN10300 AM34 CPU subarch and implement SMP support for
MN10300.  Also implement support for the MN2WS0060 processor and the ASB2364
evaluation board which are AM34 based.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 37 insertions, 4 deletions

diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index 243e33cd874b..b2e85ed73a54 100644
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -57,6 +57,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
+#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
 /*
  * we use this if we don't have any better idle routine
  */
@@ -69,6 +70,35 @@ static void default_idle(void)
                 local_irq_enable();
 }
 
+#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU  */
+/*
+ * On SMP it's slightly faster (but much more power-consuming!)
+ * to poll the ->work.need_resched flag instead of waiting for the
+ * cross-CPU IPI to arrive. Use this option with caution.
+ */
+static inline void poll_idle(void)
+{
+        int oldval;
+
+        local_irq_enable();
+
+        /*
+         * Deal with another CPU just having chosen a thread to
+         * run here:
+         */
+        oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+
+        if (!oldval) {
+                set_thread_flag(TIF_POLLING_NRFLAG);
+                while (!need_resched())
+                        cpu_relax();
+                clear_thread_flag(TIF_POLLING_NRFLAG);
+        } else {
+                set_need_resched();
+        }
+}
+#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
+
 /*
  * the idle thread
  * - there's no useful work to be done, so just try to conserve power and have
@@ -77,8 +107,6 @@ static void default_idle(void)
  */
 void cpu_idle(void)
 {
-        int cpu = smp_processor_id();
-
         /* endless idle loop with no priority at all */
         for (;;) {
                 while (!need_resched()) {
@@ -86,8 +114,13 @@ void cpu_idle(void)
 
                         smp_rmb();
                         idle = pm_idle;
-                        if (!idle)
+                        if (!idle) {
+#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
+                                idle = poll_idle;
+#else  /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
                                 idle = default_idle;
+#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
+                        }
                         idle();
                 }
 
@@ -233,7 +266,7 @@ int copy_thread(unsigned long clone_flags,
         }
 
         /* set up things up so the scheduler can start the new task */
-        p->thread.__frame = c_kregs;
+        p->thread.frame = c_kregs;
         p->thread.a3    = (unsigned long) c_kregs;
         p->thread.sp    = c_ksp;
         p->thread.pc    = (unsigned long) ret_from_fork;