2011-05-20 Jennifer Averett <Jennifer.Averett@OARcorp.com>

	PR 1787/cpukit
	* score/include/rtems/score/percpu.h,
	score/include/rtems/score/smplock.h, score/src/smp.c,
	score/src/smplock.c: Add nesting support to smp spinlock.

2 files changed, 78 insertions, 20 deletions

diff --git a/cpukit/score/src/smp.c b/cpukit/score/src/smp.c
index 068285c114..9714add5ea 100644
--- a/cpukit/score/src/smp.c
+++ b/cpukit/score/src/smp.c
@@ -80,10 +80,10 @@ void rtems_smp_process_interrupt(void)
 
   cpu = bsp_smp_processor_id();
 
-  level = _SMP_lock_Spinlock_Obtain( &_Per_CPU_Information[cpu].lock );
+  level = _SMP_lock_spinlock_simple_Obtain( &_Per_CPU_Information[cpu].lock );
     message = _Per_CPU_Information[cpu].message;
     _Per_CPU_Information[cpu].message &= ~message;
-  _SMP_lock_Spinlock_Release( &_Per_CPU_Information[cpu].lock, level );
+  _SMP_lock_spinlock_simple_Release( &_Per_CPU_Information[cpu].lock, level );
 
   #if defined(SMP_DEBUG)
     {
@@ -126,9 +126,9 @@ void rtems_smp_send_message(
 {
   ISR_Level level;
 
-  level = _SMP_lock_Spinlock_Obtain( &_Per_CPU_Information[cpu].lock );
+  level = _SMP_lock_spinlock_simple_Obtain( &_Per_CPU_Information[cpu].lock );
     _Per_CPU_Information[cpu].message |= message;
-  _SMP_lock_Spinlock_Release( &_Per_CPU_Information[cpu].lock, level );
+  _SMP_lock_spinlock_simple_Release( &_Per_CPU_Information[cpu].lock, level );
   bsp_smp_interrupt_cpu( cpu );
 }
 
@@ -145,9 +145,9 @@ void rtems_smp_broadcast_message(
   for ( dest_cpu=0 ; dest_cpu <  _SMP_Processor_count; dest_cpu++ ) {
     if ( cpu == dest_cpu )
       continue;
-    level = _SMP_lock_Spinlock_Obtain( &_Per_CPU_Information[cpu].lock );
+    level = _SMP_lock_spinlock_simple_Obtain( &_Per_CPU_Information[cpu].lock );
       _Per_CPU_Information[dest_cpu].message |= message;
-    _SMP_lock_Spinlock_Release( &_Per_CPU_Information[cpu].lock, level );
+    _SMP_lock_spinlock_simple_Release( &_Per_CPU_Information[cpu].lock, level );
   }
   bsp_smp_broadcast_interrupt();
 }
diff --git a/cpukit/score/src/smplock.c b/cpukit/score/src/smplock.c
index 1dd691835b..91589b5c54 100644
--- a/cpukit/score/src/smplock.c
+++ b/cpukit/score/src/smplock.c
@@ -15,35 +15,93 @@
 
 #include <rtems/system.h>
 #include <rtems/score/smplock.h>
+#include <rtems/score/smp.h>
 
-void _SMP_lock_Spinlock_Initialize(
-  SMP_lock_Control *lock
+#if defined (RTEMS_DEBUG)
+  #include <rtems/bspIo.h>
+#endif
+
+void _SMP_lock_spinlock_simple_Initialize(
+  SMP_lock_spinlock_simple_Control *lock
 )
 {
   *lock = 0;
 }
 
-ISR_Level _SMP_lock_Spinlock_Obtain(
-  SMP_lock_Control *lock
+ISR_Level _SMP_lock_spinlock_simple_Obtain(
+  SMP_lock_spinlock_simple_Control *lock
+)
+{
+   ISR_Level  level;
+   uint32_t   value = 1;
+   uint32_t   previous;
+ 
+   /* Note: Disable provides an implicit memory barrier. */
+  _ISR_Disable( level );
+   do {
+     SMP_CPU_SWAP( lock, value, previous );
+   } while (previous == 1);
+
+  return level;
+}
+
+void _SMP_lock_spinlock_simple_Release(
+  SMP_lock_spinlock_simple_Control *lock,
+  ISR_Level                        level
+)
+{
+   *lock = 0;
+   _ISR_Enable( level );
+}
+
+void _SMP_lock_spinlock_nested_Initialize(
+  SMP_lock_spinlock_nested_Control *lock
+)
+{
+  lock->count = 0;
+  lock->cpu_id = 0;
+}
+
+ISR_Level _SMP_lock_spinlock_nested_Obtain(
+  SMP_lock_spinlock_nested_Control *lock
 )
 {
-  ISR_Level  level;
+  ISR_Level  level = 0;
   uint32_t   value = 1;
   uint32_t   previous;
+  int        cpu_id;
 
   /* Note: Disable provides an implicit memory barrier. */
-  _ISR_Disable( level );
-    do {
-      SMP_CPU_SWAP( lock, value, previous );
-    } while (previous == 1);
+  _ISR_Disable( level ); 
+
+  cpu_id = bsp_smp_processor_id();
+
+  /* Deal with nested calls from one cpu */
+  if ( (lock->count > 0) && (cpu_id == lock->cpu_id) ) {
+    lock->count++;
+    return level;
+  }
+    
+  do {
+    SMP_CPU_SWAP( lock, value, previous );
+  } while (previous == 1);
+
+  lock->count++;
+  lock->cpu_id = cpu_id;
+
   return level;
 }
 
-void _SMP_lock_Spinlock_Release(
-  SMP_lock_Control *lock,
-  ISR_Level        level
+void _SMP_lock_spinlock_nested_Release(
+  SMP_lock_spinlock_nested_Control *lock,
+  ISR_Level                        level
 )
 {
-  *lock = 0;
-  _ISR_Enable( level );
+#if defined(RTEMS_DEBUG)
+  if ( lock->count == 0 )
+    printk ("Releasing spinlock when count is already zero?!?!\n");
+#endif
+  lock->count--;
+  
+  _ISR_Enable( level ); 
 }