score: Add self-contained condition implementation

1 files changed, 309 insertions, 0 deletions

diff --git a/cpukit/score/src/condition.c b/cpukit/score/src/condition.c
new file mode 100644
index 0000000000..22c2a9b97c
--- /dev/null
+++ b/cpukit/score/src/condition.c
@@ -0,0 +1,309 @@
+/*
+ * Copyright (c) 2015 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#if HAVE_STRUCT__THREAD_QUEUE_QUEUE
+
+#include <sys/lock.h>
+#include <errno.h>
+
+#include <rtems/score/atomic.h>
+#include <rtems/score/chainimpl.h>
+#include <rtems/score/threadimpl.h>
+#include <rtems/score/threadqimpl.h>
+#include <rtems/score/todimpl.h>
+#include <rtems/score/watchdogimpl.h>
+
+#define CONDITION_TQ_OPERATIONS &_Thread_queue_Operations_FIFO
+
+typedef struct {
+  Thread_queue_Syslock_queue Queue;
+} Condition_Control;
+
+RTEMS_STATIC_ASSERT(
+  offsetof( Condition_Control, Queue )
+    == offsetof( struct _Condition_Control, _Queue ),
+  CONDITION_CONTROL_QUEUE
+);
+
+RTEMS_STATIC_ASSERT(
+  sizeof( Condition_Control ) == sizeof( struct _Condition_Control ),
+  CONDITION_CONTROL_SIZE
+);
+
+static Condition_Control *_Condition_Get(
+  struct _Condition_Control *_condition
+)
+{
+  return (Condition_Control *) _condition;
+}
+
+static Thread_Control *_Condition_Queue_acquire_critical(
+  Condition_Control *condition,
+  ISR_lock_Context  *lock_context
+)
+{
+  Thread_Control *executing;
+
+  executing = _Thread_Executing;
+  _Thread_queue_Queue_acquire_critical(
+    &condition->Queue.Queue,
+    &executing->Potpourri_stats,
+    lock_context
+  );
+
+  return executing;
+}
+
+static void _Condition_Queue_release(
+  Condition_Control *condition,
+  ISR_lock_Context  *lock_context
+)
+{
+  _Thread_queue_Queue_release( &condition->Queue.Queue, lock_context );
+}
+
+static Per_CPU_Control *_Condition_Do_wait(
+  struct _Condition_Control *_condition,
+  Watchdog_Interval          timeout,
+  ISR_lock_Context          *lock_context
+)
+{
+  Condition_Control *condition;
+  Thread_Control    *executing;
+  Per_CPU_Control   *cpu_self;
+
+  condition = _Condition_Get( _condition );
+  executing = _Condition_Queue_acquire_critical( condition, lock_context );
+  cpu_self = _Thread_Dispatch_disable_critical( lock_context );
+
+  executing->Wait.return_code = 0;
+  _Thread_queue_Enqueue_critical(
+    &condition->Queue.Queue,
+    CONDITION_TQ_OPERATIONS,
+    executing,
+    STATES_WAITING_FOR_SYS_LOCK_CONDITION,
+    timeout,
+    ETIMEDOUT,
+    lock_context
+  );
+
+  return cpu_self;
+}
+
+void _Condition_Wait(
+  struct _Condition_Control *_condition,
+  struct _Mutex_Control     *_mutex
+)
+{
+  ISR_lock_Context  lock_context;
+  Per_CPU_Control  *cpu_self;
+
+  _ISR_lock_ISR_disable( &lock_context );
+  cpu_self = _Condition_Do_wait( _condition, 0, &lock_context );
+
+  _Mutex_Release( _mutex );
+  _Thread_Dispatch_enable( cpu_self );
+  _Mutex_Acquire( _mutex );
+}
+
+int _Condition_Wait_timed(
+  struct _Condition_Control *_condition,
+  struct _Mutex_Control     *_mutex,
+  const struct timespec     *abstime
+)
+{
+  ISR_lock_Context   lock_context;
+  Per_CPU_Control   *cpu_self;
+  Thread_Control    *executing;
+  int                eno;
+  Watchdog_Interval  ticks;
+
+  _ISR_lock_ISR_disable( &lock_context );
+
+  switch ( _TOD_Absolute_timeout_to_ticks( abstime, &ticks ) ) {
+    case TOD_ABSOLUTE_TIMEOUT_INVALID:
+      _ISR_lock_ISR_enable( &lock_context );
+      return EINVAL;
+    case TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST:
+    case TOD_ABSOLUTE_TIMEOUT_IS_NOW:
+      _ISR_lock_ISR_enable( &lock_context );
+      return ETIMEDOUT;
+    default:
+      break;
+  }
+
+  cpu_self = _Condition_Do_wait( _condition, ticks, &lock_context );
+
+  _Mutex_Release( _mutex );
+  executing = cpu_self->executing;
+  _Thread_Dispatch_enable( cpu_self );
+  eno = (int) executing->Wait.return_code;
+  _Mutex_Acquire( _mutex );
+
+  return eno;
+}
+
+void _Condition_Wait_recursive(
+  struct _Condition_Control       *_condition,
+  struct _Mutex_recursive_Control *_mutex
+)
+{
+  ISR_lock_Context  lock_context;
+  Per_CPU_Control  *cpu_self;
+  unsigned int      nest_level;
+
+  _ISR_lock_ISR_disable( &lock_context );
+  cpu_self = _Condition_Do_wait( _condition, 0, &lock_context );
+
+  nest_level = _mutex->_nest_level;
+  _mutex->_nest_level = 0;
+  _Mutex_recursive_Release( _mutex );
+  _Thread_Dispatch_enable( cpu_self );
+  _Mutex_recursive_Acquire( _mutex );
+  _mutex->_nest_level = nest_level;
+}
+
+int _Condition_Wait_recursive_timed(
+  struct _Condition_Control       *_condition,
+  struct _Mutex_recursive_Control *_mutex,
+  const struct timespec           *abstime
+)
+{
+  ISR_lock_Context   lock_context;
+  Per_CPU_Control   *cpu_self;
+  Thread_Control    *executing;
+  int                eno;
+  unsigned int       nest_level;
+  Watchdog_Interval  ticks;
+
+  _ISR_lock_ISR_disable( &lock_context );
+
+  switch ( _TOD_Absolute_timeout_to_ticks( abstime, &ticks ) ) {
+    case TOD_ABSOLUTE_TIMEOUT_INVALID:
+      _ISR_lock_ISR_enable( &lock_context );
+      return EINVAL;
+    case TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST:
+    case TOD_ABSOLUTE_TIMEOUT_IS_NOW:
+      _ISR_lock_ISR_enable( &lock_context );
+      return ETIMEDOUT;
+    default:
+      break;
+  }
+
+  cpu_self = _Condition_Do_wait( _condition, ticks, &lock_context );
+
+  nest_level = _mutex->_nest_level;
+  _mutex->_nest_level = 0;
+  _Mutex_recursive_Release( _mutex );
+  executing = cpu_self->executing;
+  _Thread_Dispatch_enable( cpu_self );
+  eno = (int) executing->Wait.return_code;
+  _Mutex_recursive_Acquire( _mutex );
+  _mutex->_nest_level = nest_level;
+
+  return eno;
+}
+
+static int _Condition_Wake( struct _Condition_Control *_condition, int count )
+{
+  Condition_Control  *condition;
+  ISR_lock_Context    lock_context;
+  Thread_queue_Heads *heads;
+  Chain_Control       unblock;
+  Chain_Node         *node;
+  Chain_Node         *tail;
+  int                 woken;
+
+  condition = _Condition_Get( _condition );
+  _ISR_lock_ISR_disable( &lock_context );
+  _Condition_Queue_acquire_critical( condition, &lock_context );
+
+  /*
+   * In common uses cases of condition variables there are normally no threads
+   * on the queue, so check this condition early.
+   */
+  heads = condition->Queue.Queue.heads;
+  if ( __predict_true( heads == NULL ) ) {
+    _Condition_Queue_release( condition, &lock_context );
+
+    return 0;
+  }
+
+  woken = 0;
+  _Chain_Initialize_empty( &unblock );
+  while ( count > 0 && heads != NULL ) {
+    const Thread_queue_Operations *operations;
+    Thread_Control                *first;
+    bool                           do_unblock;
+
+    operations = CONDITION_TQ_OPERATIONS;
+    first = ( *operations->first )( heads );
+
+    do_unblock = _Thread_queue_Extract_locked(
+      &condition->Queue.Queue,
+      operations,
+      first
+    );
+    if (do_unblock) {
+      _Chain_Append_unprotected( &unblock, &first->Wait.Node.Chain );
+    }
+
+    ++woken;
+    --count;
+    heads = condition->Queue.Queue.heads;
+  }
+
+  node = _Chain_First( &unblock );
+  tail = _Chain_Tail( &unblock );
+  if ( node != tail ) {
+    Per_CPU_Control *cpu_self;
+
+    cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
+    _Condition_Queue_release( condition, &lock_context );
+
+    do {
+      Thread_Control *thread;
+      Chain_Node     *next;
+
+      next = _Chain_Next( node );
+      thread = THREAD_CHAIN_NODE_TO_THREAD( node );
+      _Watchdog_Remove_ticks( &thread->Timer );
+      _Thread_Unblock( thread );
+
+      node = next;
+    } while ( node != tail );
+
+    _Thread_Dispatch_enable( cpu_self );
+  } else {
+    _Condition_Queue_release( condition, &lock_context );
+  }
+
+  return woken;
+}
+
+void _Condition_Signal( struct _Condition_Control *_condition )
+{
+  _Condition_Wake( _condition, 1 );
+}
+
+void _Condition_Broadcast( struct _Condition_Control *_condition )
+{
+  _Condition_Wake( _condition, INT_MAX );
+}
+
+#endif /* HAVE_STRUCT__THREAD_QUEUE_QUEUE */