[rtems commit] score: _Per_CPU_State_wait_for_non_initial_state()

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    9a1bab2525679abc75eb321f61e4b130f8801490
Changeset: http://git.rtems.org/rtems/commit/?id=9a1bab2525679abc75eb321f61e4b130f8801490

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Thu Jun  5 11:19:32 2014 +0200

score: _Per_CPU_State_wait_for_non_initial_state()

Replace _Per_CPU_State_wait_for_ready_to_start_multitasking() with
_Per_CPU_State_wait_for_non_initial_state().  Implement this function.

---

 cpukit/score/Makefile.am                  |    1 +
 cpukit/score/include/rtems/score/percpu.h |   39 ++++++++------------
 cpukit/score/src/percpustatewait.c        |   56 +++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 24 deletions(-)

diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index feb757d..7b17569 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -130,6 +130,7 @@ libscore_a_SOURCES += src/mpci.c src/objectmp.c src/threadmp.c
 endif
 
 if HAS_SMP
+libscore_a_SOURCES += src/percpustatewait.c
 libscore_a_SOURCES += src/profilingsmplock.c
 libscore_a_SOURCES += src/schedulersmpvalidstatechanges.c
 libscore_a_SOURCES += src/schedulerpriorityaffinitysmp.c
diff --git a/cpukit/score/include/rtems/score/percpu.h b/cpukit/score/include/rtems/score/percpu.h
index e232674..30d61d5 100644
--- a/cpukit/score/include/rtems/score/percpu.h
+++ b/cpukit/score/include/rtems/score/percpu.h
@@ -547,42 +547,33 @@ void _Per_CPU_State_change(
 );
 
 /**
- * @brief Waits for all other processors to enter the ready to start
- * multitasking state with a timeout in microseconds.
+ * @brief Waits for a processor to change into a non-initial state.
  *
- * In case one processor enters the shutdown state, this function does not
- * return and terminates the system with the SMP_FATAL_SHUTDOWN_EARLY fatal SMP
- * error.
- *
- * This function should be called only in _CPU_SMP_Initialize() if required by
- * the CPU port or BSP.
+ * This function should be called only in _CPU_SMP_Start_processor() if
+ * required by the CPU port or BSP.
  *
  * @code
- * uint32_t _CPU_SMP_Initialize(uint32_t configured_cpu_count)
+ * bool _CPU_SMP_Start_processor(uint32_t cpu_index)
  * {
- *   uint32_t cnt = MIN(get_hardware_cpu_count(), configured_cpu_count);
  *   uint32_t timeout = 123456;
  *
- *   do_some_stuff();
+ *   start_the_processor(cpu_index);
  *
- *   return _Per_CPU_State_wait_for_ready_to_start_multitasking(cnt, timeout);
+ *   return _Per_CPU_State_wait_for_non_initial_state(cpu_index, timeout);
  * }
  * @endcode
  *
- * In case the timeout expires the count of processors is reduced to reflect
- * the set of processors which is actually available at this point in time.
- *
- * @param[in] processor_count The processor count is the minimum value of the
- * configured count of processors and the processor count offered by the actual
- * hardware.
- * @param[in] timeout_in_us The timeout in microseconds.
+ * @param[in] cpu_index The processor index.
+ * @param[in] timeout_in_ns The timeout in nanoseconds.  Use a value of zero to
+ * wait forever if necessary.
  *
- * @return The count of processors available for the application in the system.
- * This value is less than or equal to the processor count.
+ * @retval true The processor is in a non-initial state.
+ * @retval false The timeout expired before the processor reached a non-initial
+ * state.
  */
-uint32_t _Per_CPU_State_wait_for_ready_to_start_multitasking(
-  uint32_t processor_count,
-  uint32_t timeout_in_us
+bool _Per_CPU_State_wait_for_non_initial_state(
+  uint32_t cpu_index,
+  uint32_t timeout_in_ns
 );
 
 #endif /* defined( RTEMS_SMP ) */
diff --git a/cpukit/score/src/percpustatewait.c b/cpukit/score/src/percpustatewait.c
new file mode 100644
index 0000000..bde367b
--- /dev/null
+++ b/cpukit/score/src/percpustatewait.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems at 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
+
+#include <rtems/score/percpu.h>
+#include <rtems/counter.h>
+
+bool _Per_CPU_State_wait_for_non_initial_state(
+  uint32_t cpu_index,
+  uint32_t timeout_in_ns
+)
+{
+  const Per_CPU_Control *cpu = _Per_CPU_Get_by_index( cpu_index );
+  Per_CPU_State state = cpu->state;
+
+  if ( timeout_in_ns > 0 ) {
+    rtems_counter_ticks ticks =
+      rtems_counter_nanoseconds_to_ticks( timeout_in_ns );
+    rtems_counter_ticks a = rtems_counter_read();
+    rtems_counter_ticks delta = 0;
+
+    while ( ticks > delta && state == PER_CPU_STATE_INITIAL ) {
+      rtems_counter_ticks b;
+
+      _CPU_SMP_Processor_event_receive();
+      state = cpu->state;
+
+      ticks -= delta;
+
+      b = rtems_counter_read();
+      delta = rtems_counter_difference( b, a );
+      a = b;
+    }
+  } else {
+    while ( state == PER_CPU_STATE_INITIAL ) {
+      _CPU_SMP_Processor_event_receive();
+      state = cpu->state;
+    }
+  }
+
+  return state != PER_CPU_STATE_INITIAL;
+}