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, 70 insertions, 22 deletions

diff --git a/cpukit/score/include/rtems/score/percpu.h b/cpukit/score/include/rtems/score/percpu.h
index 9224ad0d2e..1ba5b3d6d2 100644
--- a/cpukit/score/include/rtems/score/percpu.h
+++ b/cpukit/score/include/rtems/score/percpu.h
@@ -92,18 +92,17 @@ typedef enum {
 typedef struct {
   #if defined(RTEMS_SMP)
     /** This element is used to lock this structure */
-    SMP_lock_Control  lock; 
+    SMP_lock_spinlock_simple_Control  lock; 
 
     /** This indicates that the CPU is online. */
-    uint32_t          state; 
+    uint32_t                          state; 
 
     /**
      *  This is the request for the interrupt.
      *  
      *  @note This may become a chain protected by atomic instructions.
      */
-    uint32_t          message; 
-
+    uint32_t                          message; 
   #endif
 
 #if (CPU_ALLOCATE_INTERRUPT_STACK == TRUE) || \
diff --git a/cpukit/score/include/rtems/score/smplock.h b/cpukit/score/include/rtems/score/smplock.h
index a20d9260a4..279df6ecd8 100644
--- a/cpukit/score/include/rtems/score/smplock.h
+++ b/cpukit/score/include/rtems/score/smplock.h
@@ -34,10 +34,23 @@ extern "C" {
 
 /**
  *  This type is used to lock elements for atomic access.
- *
- *  @note This type may move to RTEMS.
+ *  This spinlock is a simple non-nesting spinlock, and
+ *  may be used for short non-nesting accesses.  
+ */
+typedef uint32_t SMP_lock_spinlock_simple_Control;
+
+/**
+ *  This type is used to lock elements for atomic access.
+ *  This spinlock supports nesting, but is slightly more
+ *  complicated to use.  Please see the descriptions of
+ *  obtain and release prior to using in order to understand
+ *  the callers responsibilty of managing short interupt disable
+ *  times.
  */
-typedef volatile uint32_t SMP_lock_Control;
+typedef struct {
+  uint32_t  count;
+  int       cpu_id;
+} SMP_lock_spinlock_nested_Control;
 
 /**
  *  @brief Initialize a Lock
@@ -45,12 +58,9 @@ typedef volatile uint32_t SMP_lock_Control;
  *  This method is used to initialize the lock at @a lock.
  *
  *  @param [in] lock is the address of the lock to obtain.
- *
- *  @note This lock may be "too low" here.  It may need to move
- *         out of the BSP area.
  */
-void _SMP_lock_Spinlock_Initialize(
-  SMP_lock_Control *lock
+void _SMP_lock_spinlock_simple_Initialize(
+  SMP_lock_spinlock_simple_Control *lock
 );
 
 /**
@@ -62,12 +72,9 @@ void _SMP_lock_Spinlock_Initialize(
  *
  *  @return This method returns with processor interrupts disabled.
  *          The previous level is returned.
- *
- *  @note This lock may be "too low" here.  It may need to move
- *         out of the BSP area.
  */
-ISR_Level _SMP_lock_Spinlock_Obtain(
-  SMP_lock_Control *lock
+ISR_Level _SMP_lock_spinlock_simple_Obtain(
+  SMP_lock_spinlock_simple_Control *lock
 );
 
 /**
@@ -76,13 +83,55 @@ ISR_Level _SMP_lock_Spinlock_Obtain(
  *  This method is used to release the lock at @a lock.
  *
  *  @param [in] lock is the address of the lock to obtain.
+ */
+void _SMP_lock_spinlock_simple_Release(
+  SMP_lock_spinlock_simple_Control  *lock,
+  ISR_Level                         level
+);
+
+/**
+ *  @brief Initialize a Lock
+ *
+ *  This method is used to initialize the lock at @a lock.
+ *
+ *  @param [in] lock is the address of the lock to obtain.
+ */
+void _SMP_lock_spinlock_nested_Initialize(
+  SMP_lock_spinlock_nested_Control *lock
+);
+
+/**
+ *  @brief Obtain a Lock
+ *
+ *  This method is used to obtain the lock at @a lock.  ISR's are
+ *  disabled when this routine returns and it is the callers responsibility
+ *  to either:
+ *   1) Do something very short and then call 
+ *      _SMP_lock_spinlock_nested_Release  or
+ *   2) Do something very sort, call isr enable, then when ready 
+ *      call isr_disable and _SMP_lock_spinlock_nested_Release
+ *
+ *  @param [in] lock is the address of the lock to obtain.
  *
- *  @note This lock may be "too low" here.  It may need to move
- *         out of the BSP area.
+ *  @return This method returns with processor interrupts disabled.
+ *          The previous level is returned.
+ */
+ISR_Level _SMP_lock_spinlock_nested_Obtain(
+  SMP_lock_spinlock_nested_Control *lock
+);
+
+/**
+ *  @brief Release a Lock
+ *
+ *  This method is used to release the lock at @a lock.  Note:
+ *  ISR's are reenabled by this method and are expected to be
+ *  disabled upon entry to the method.
+ *
+ *  @param [in] lock is the address of the lock to obtain.
  */
-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
 );
 
 #ifdef __cplusplus