2011-09-15 Petr Benes <benesp16@fel.cvut.cz>

	PR 1906/cpukit
	* sapi/Makefile.am, sapi/preinstall.am, sapi/include/confdefs.h,
	score/Makefile.am, score/preinstall.am: Add the CBS (Constant
	Bandwidth Server) scheduler. This is a complex scheduling policy
	built atop of the EDF scheduler. Unlike other schedulers, this one
	provides a user API and handles not only deadlines of tasks but also
	claimed budget per period. The main aim of the scheduler is isolation
	of tasks so that each task is guaranteed to meet all deadlines
	regardless of how other tasks behave.
	* sapi/include/rtems/cbs.h, sapi/inline/rtems/cbs.inl,
	score/include/rtems/score/schedulercbs.h, score/src/schedulercbs.c,
	score/src/schedulercbsattachthread.c,
	score/src/schedulercbscleanup.c,
	score/src/schedulercbscreateserver.c,
	score/src/schedulercbsdestroyserver.c,
	score/src/schedulercbsdetachthread.c,
	score/src/schedulercbsgetapprovedbudget.c,
	score/src/schedulercbsgetexecutiontime.c,
	score/src/schedulercbsgetparameters.c,
	score/src/schedulercbsgetremainingbudget.c,
	score/src/schedulercbsgetserverid.c,
	score/src/schedulercbsreleasejob.c,
	score/src/schedulercbssetparameters.c,
	score/src/schedulercbsunblock.c: New files.

23 files changed, 1361 insertions, 1 deletions

diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog
index 4e5423fb65..3db300ffb2 100644
--- a/cpukit/ChangeLog
+++ b/cpukit/ChangeLog
@@ -1,3 +1,30 @@
+2011-09-15	Petr Benes <benesp16@fel.cvut.cz>
+
+	PR 1906/cpukit
+	* sapi/Makefile.am, sapi/preinstall.am, sapi/include/confdefs.h,
+	score/Makefile.am, score/preinstall.am: Add the CBS (Constant
+	Bandwidth Server) scheduler. This is a complex scheduling policy
+	built atop of the EDF scheduler. Unlike other schedulers, this one
+	provides a user API and handles not only deadlines of tasks but also
+	claimed budget per period. The main aim of the scheduler is isolation
+	of tasks so that each task is guaranteed to meet all deadlines
+	regardless of how other tasks behave.
+	* sapi/include/rtems/cbs.h, sapi/inline/rtems/cbs.inl,
+	score/include/rtems/score/schedulercbs.h, score/src/schedulercbs.c,
+	score/src/schedulercbsattachthread.c,
+	score/src/schedulercbscleanup.c,
+	score/src/schedulercbscreateserver.c,
+	score/src/schedulercbsdestroyserver.c,
+	score/src/schedulercbsdetachthread.c,
+	score/src/schedulercbsgetapprovedbudget.c,
+	score/src/schedulercbsgetexecutiontime.c,
+	score/src/schedulercbsgetparameters.c,
+	score/src/schedulercbsgetremainingbudget.c,
+	score/src/schedulercbsgetserverid.c,
+	score/src/schedulercbsreleasejob.c,
+	score/src/schedulercbssetparameters.c,
+	score/src/schedulercbsunblock.c: New files.
+
 2011-09-15	Sebastian Huber <sebastian.huber@embedded-brains.de>
 
 	* cpukit/libmisc/cpuuse/cpuuse.h,
diff --git a/cpukit/sapi/Makefile.am b/cpukit/sapi/Makefile.am
index aadccf4b76..9b7ad53201 100644
--- a/cpukit/sapi/Makefile.am
+++ b/cpukit/sapi/Makefile.am
@@ -15,6 +15,7 @@ include_rtems_HEADERS += include/rtems/fatal.h
 include_rtems_HEADERS += include/rtems/init.h
 include_rtems_HEADERS += include/rtems/io.h
 include_rtems_HEADERS += include/rtems/mptables.h
+include_rtems_HEADERS += include/rtems/cbs.h
 include_rtems_HEADERS += include/rtems/rbtree.h
 include_rtems_HEADERS += include/rtems/sptables.h
 
@@ -22,6 +23,7 @@ EXTRA_DIST = include/rtems/README
 
 include_rtems_HEADERS += inline/rtems/chain.inl
 include_rtems_HEADERS += inline/rtems/extension.inl
+include_rtems_HEADERS += inline/rtems/cbs.inl
 include_rtems_HEADERS += inline/rtems/rbtree.inl
 
 ## src
diff --git a/cpukit/sapi/include/confdefs.h b/cpukit/sapi/include/confdefs.h
index 2a9d75ac2c..a82dd00a87 100644
--- a/cpukit/sapi/include/confdefs.h
+++ b/cpukit/sapi/include/confdefs.h
@@ -574,6 +574,7 @@ rtems_fs_init_functions_t    rtems_fs_init_helper =
  *  CONFIGURE_SCHEDULER_SIMPLE     - Light-weight Priority Scheduler
  *  CONFIGURE_SCHEDULER_SIMPLE_SMP - Simple SMP Priority Scheduler
  *  CONFIGURE_SCHEDULER_EDF        - EDF Scheduler
+ *  CONFIGURE_SCHEDULER_CBS        - CBS Scheduler
  * 
  * If no configuration is specified by the application, then 
  * CONFIGURE_SCHEDULER_PRIORITY is assumed to be the default.
@@ -600,7 +601,8 @@ rtems_fs_init_functions_t    rtems_fs_init_helper =
     !defined(CONFIGURE_SCHEDULER_PRIORITY) && \
     !defined(CONFIGURE_SCHEDULER_SIMPLE) && \
     !defined(CONFIGURE_SCHEDULER_SIMPLE_SMP) && \
-    !defined(CONFIGURE_SCHEDULER_EDF)
+    !defined(CONFIGURE_SCHEDULER_EDF) && \
+    !defined(CONFIGURE_SCHEDULER_CBS)
   #if defined(RTEMS_SMP) && defined(CONFIGURE_SMP_APPLICATION)
     #define CONFIGURE_SCHEDULER_SIMPLE_SMP
   #else
@@ -676,6 +678,31 @@ rtems_fs_init_functions_t    rtems_fs_init_helper =
     _Configure_From_workspace(sizeof(Scheduler_EDF_Per_thread)))
 #endif
 
+/*
+ * If the CBS Scheduler is selected, then configure for it.
+ */
+#if defined(CONFIGURE_SCHEDULER_CBS)
+  #include <rtems/score/schedulercbs.h>
+  #define CONFIGURE_SCHEDULER_ENTRY_POINTS SCHEDULER_CBS_ENTRY_POINTS
+
+  #ifndef CONFIGURE_CBS_MAXIMUM_SERVERS
+    #define CONFIGURE_CBS_MAXIMUM_SERVERS CONFIGURE_MAXIMUM_TASKS
+  #endif
+
+  #ifdef CONFIGURE_INIT
+    uint32_t _Scheduler_CBS_Maximum_servers = CONFIGURE_CBS_MAXIMUM_SERVERS;
+  #endif
+
+  /**
+   * define the memory used by the CBS scheduler
+   */
+  #define CONFIGURE_MEMORY_FOR_SCHEDULER ( \
+    _Configure_From_workspace((sizeof(Scheduler_CBS_Server) + \
+        sizeof(Scheduler_CBS_Server*)) * CONFIGURE_CBS_MAXIMUM_SERVERS))
+  #define CONFIGURE_MEMORY_PER_TASK_FOR_SCHEDULER ( \
+    _Configure_From_workspace(sizeof(Scheduler_CBS_Per_thread)))
+#endif
+
 #if defined(CONFIGURE_SCHEDULER_USER)
   #define CONFIGURE_SCHEDULER_ENTRY_POINTS \
           CONFIGURE_SCHEDULER_USER_ENTRY_POINTS
diff --git a/cpukit/sapi/include/rtems/cbs.h b/cpukit/sapi/include/rtems/cbs.h
new file mode 100644
index 0000000000..d016e5cdec
--- /dev/null
+++ b/cpukit/sapi/include/rtems/cbs.h
@@ -0,0 +1,65 @@
+/**
+ * @file rtems/cbs.h
+ *
+ *  This include file contains all the constants and structures associated
+ *  with the CBS library in RTEMS.
+ */
+
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#ifndef CONFIGURE_SCHEDULER_CBS
+  #error "cbs.h available only with CONFIGURE_SCHEDULER_CBS"
+#endif
+
+#ifndef _RTEMS_CBS_H
+#define _RTEMS_CBS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <rtems/score/schedulercbs.h>
+
+/* Return codes. */
+#define RTEMS_CBS_OK                       SCHEDULER_CBS_OK
+#define RTEMS_CBS_ERROR_GENERIC            SCHEDULER_CBS_ERROR_GENERIC
+#define RTEMS_CBS_ERROR_NO_MEMORY          SCHEDULER_CBS_ERROR_NO_MEMORY
+#define RTEMS_CBS_ERROR_INVALID_PARAMETER  SCHEDULER_CBS_ERROR_INVALID_PARAM
+#define RTEMS_CBS_ERROR_UNAUTHORIZED       SCHEDULER_CBS_ERROR_UNAUTHORIZED
+#define RTEMS_CBS_ERROR_UNIMPLEMENTED      SCHEDULER_CBS_ERROR_UNIMPLEMENTED
+#define RTEMS_CBS_ERROR_MISSING_COMPONENT  SCHEDULER_CBS_ERROR_MISSING_COMPONENT
+#define RTEMS_CBS_ERROR_INCONSISTENT_STATE SCHEDULER_CBS_ERROR_INCONSISTENT_STATE
+#define RTEMS_CBS_ERROR_SYSTEM_OVERLOAD    SCHEDULER_CBS_ERROR_SYSTEM_OVERLOAD
+#define RTEMS_CBS_ERROR_INTERNAL_ERROR     SCHEDULER_CBS_ERROR_INTERNAL_ERROR
+#define RTEMS_CBS_ERROR_NOT_FOUND          SCHEDULER_CBS_ERROR_NOT_FOUND
+#define RTEMS_CBS_ERROR_FULL               SCHEDULER_CBS_ERROR_FULL
+#define RTEMS_CBS_ERROR_EMPTY              SCHEDULER_CBS_ERROR_EMPTY
+#define RTEMS_CBS_ERROR_NOSERVER           SCHEDULER_CBS_ERROR_NOSERVER
+
+/** Callback function invoked when a budget overrun of a task occurs. */
+typedef Scheduler_CBS_Budget_overrun rtems_cbs_budget_overrun;
+
+/** Server id. */
+typedef Scheduler_CBS_Server_id rtems_cbs_server_id;
+
+/** Server parameters. */
+typedef Scheduler_CBS_Parameters rtems_cbs_parameters;
+
+#include <rtems/cbs.inl>
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/* end of include file */
diff --git a/cpukit/sapi/inline/rtems/cbs.inl b/cpukit/sapi/inline/rtems/cbs.inl
new file mode 100644
index 0000000000..451d8cbc04
--- /dev/null
+++ b/cpukit/sapi/inline/rtems/cbs.inl
@@ -0,0 +1,205 @@
+/**
+ * @file cbs.inl
+ *
+ *  This include file contains all the constants and structures associated
+ *  with the CBS library.
+ *
+ */
+
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#ifndef _RTEMS_CBS_H
+# error "Never use <rtems/cbs.inl> directly; include <rtems/cbs.h> instead."
+#endif
+
+#include <rtems/score/schedulercbs.h>
+
+/**
+ *  @brief rtems cbs init
+ *
+ *  Initializes the CBS library.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_initialize ( void )
+{
+  return _Scheduler_CBS_Initialize();
+}
+
+/**
+ *  @brief rtems cbs cleanup
+ *
+ *  Cleanup resources associated to the CBS Library.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_cleanup ( void )
+{
+  return _Scheduler_CBS_Cleanup();
+}
+
+/**
+ *  @brief rtems cbs create server
+ *
+ *  Create a new server with specified parameters.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_create_server (
+  rtems_cbs_parameters     *params,
+  rtems_cbs_budget_overrun  budget_overrun_callback,
+  rtems_cbs_server_id      *server_id
+)
+{
+  return _Scheduler_CBS_Create_server(
+             params,
+             budget_overrun_callback,
+             server_id
+         );
+}
+
+/**
+ *  @brief rtems cbs attach thread
+ *
+ *  Attach a task to an already existing server.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_attach_thread (
+  rtems_cbs_server_id server_id,
+  rtems_id            task_id
+)
+{
+  return _Scheduler_CBS_Attach_thread( server_id, task_id );
+}
+
+/**
+ *  @brief rtems cbs detach thread
+ *
+ *  Detach from the CBS Server.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_detach_thread (
+  rtems_cbs_server_id server_id,
+  rtems_id            task_id
+)
+{
+  return _Scheduler_CBS_Detach_thread( server_id, task_id );
+}
+
+/**
+ *  @brief rtems cbs destroy server
+ *
+ *  Detach all tasks from a server and destroy it.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_destroy_server (
+  rtems_cbs_server_id server_id
+)
+{
+  return _Scheduler_CBS_Destroy_server( server_id );
+}
+
+/**
+ *  @brief rtems cbs get server id
+ *
+ *  Get a thread server id, or RTEMS_CBS_E_NOT_FOUND if it is not
+ *  attached to any server.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_get_server_id (
+  rtems_id             task_id,
+  rtems_cbs_server_id *server_id
+)
+{
+  return _Scheduler_CBS_Get_server_id( task_id, server_id );
+}
+
+/**
+ *  @brief rtems cbs get parameters
+ *
+ *  Retrieve CBS scheduling parameters.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_get_parameters (
+  rtems_cbs_server_id   server_id,
+  rtems_cbs_parameters *params
+)
+{
+  return _Scheduler_CBS_Get_parameters( server_id, params );
+}
+
+/**
+ *  @brief rtems cbs set parameters
+ *
+ *  Change CBS scheduling parameters.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_set_parameters (
+  rtems_cbs_server_id   server_id,
+  rtems_cbs_parameters *params
+)
+{
+  return _Scheduler_CBS_Set_parameters( server_id, params );
+}
+
+/**
+ *  @brief rtems cbs get execution time
+ *
+ *  Retrieve time info relative to the current server.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_get_execution_time (
+  rtems_cbs_server_id    server_id,
+  time_t                *exec_time,
+  time_t                *abs_time
+)
+{
+  return _Scheduler_CBS_Get_execution_time( server_id, exec_time, abs_time );
+}
+
+/**
+ *  @brief rtems cbs get remaining budget
+ *
+ *  Retrieve remaining budget for the current server instance.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_get_remaining_budget (
+  rtems_cbs_server_id  server_id,
+  time_t              *remaining_budget
+)
+{
+  return _Scheduler_CBS_Get_remaining_budget( server_id, remaining_budget );
+}
+
+/**
+ *  @brief rtems cbs get approved budget
+ *
+ *  Retrieve the budget that has been approved for the subsequent
+ *  server instances.
+ *
+ *  @return status code.
+ */
+RTEMS_INLINE_ROUTINE int rtems_cbs_get_approved_budget (
+  rtems_cbs_server_id  server_id,
+  time_t              *appr_budget
+)
+{
+  return _Scheduler_CBS_Get_approved_budget( server_id, appr_budget );
+}
diff --git a/cpukit/sapi/preinstall.am b/cpukit/sapi/preinstall.am
index f49f81427c..5ce9966786 100644
--- a/cpukit/sapi/preinstall.am
+++ b/cpukit/sapi/preinstall.am
@@ -60,6 +60,10 @@ $(PROJECT_INCLUDE)/rtems/mptables.h: include/rtems/mptables.h $(PROJECT_INCLUDE)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/mptables.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/mptables.h
 
+$(PROJECT_INCLUDE)/rtems/cbs.h: include/rtems/cbs.h $(PROJECT_INCLUDE)/rtems/$(dirstamp)
+	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/cbs.h
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/cbs.h
+
 $(PROJECT_INCLUDE)/rtems/rbtree.h: include/rtems/rbtree.h $(PROJECT_INCLUDE)/rtems/$(dirstamp)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/rbtree.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/rbtree.h
@@ -76,6 +80,10 @@ $(PROJECT_INCLUDE)/rtems/extension.inl: inline/rtems/extension.inl $(PROJECT_INC
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/extension.inl
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/extension.inl
 
+$(PROJECT_INCLUDE)/rtems/cbs.inl: inline/rtems/cbs.inl $(PROJECT_INCLUDE)/rtems/$(dirstamp)
+	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/cbs.inl
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/cbs.inl
+
 $(PROJECT_INCLUDE)/rtems/rbtree.inl: inline/rtems/rbtree.inl $(PROJECT_INCLUDE)/rtems/$(dirstamp)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/rbtree.inl
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/rbtree.inl
diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index d05ccfdb81..44a0df4c4f 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -40,6 +40,7 @@ include_rtems_score_HEADERS += include/rtems/score/priority.h
 include_rtems_score_HEADERS += include/rtems/score/prioritybitmap.h
 include_rtems_score_HEADERS += include/rtems/score/rbtree.h
 include_rtems_score_HEADERS += include/rtems/score/scheduler.h
+include_rtems_score_HEADERS += include/rtems/score/schedulercbs.h
 include_rtems_score_HEADERS += include/rtems/score/scheduleredf.h
 include_rtems_score_HEADERS += include/rtems/score/schedulerpriority.h
 include_rtems_score_HEADERS += include/rtems/score/schedulersimple.h
@@ -238,6 +239,22 @@ libscore_a_SOURCES += src/scheduleredf.c \
     src/scheduleredfupdate.c \
     src/scheduleredfyield.c
 
+## SCHEDULERCBS_C_FILES
+libscore_a_SOURCES += src/schedulercbs.c \
+    src/schedulercbsattachthread.c \
+    src/schedulercbscleanup.c \
+    src/schedulercbscreateserver.c \
+    src/schedulercbsdestroyserver.c \
+    src/schedulercbsdetachthread.c \
+    src/schedulercbsgetapprovedbudget.c \
+    src/schedulercbsgetexecutiontime.c \
+    src/schedulercbsgetparameters.c \
+    src/schedulercbsgetremainingbudget.c \
+    src/schedulercbsgetserverid.c \
+    src/schedulercbssetparameters.c \
+    src/schedulercbsreleasejob.c \
+    src/schedulercbsunblock.c
+
 ## PROTECTED_HEAP_C_FILES
 libscore_a_SOURCES += src/pheapallocate.c \
     src/pheapextend.c src/pheapfree.c src/pheapgetsize.c \
diff --git a/cpukit/score/include/rtems/score/schedulercbs.h b/cpukit/score/include/rtems/score/schedulercbs.h
new file mode 100644
index 0000000000..4cc00a65de
--- /dev/null
+++ b/cpukit/score/include/rtems/score/schedulercbs.h
@@ -0,0 +1,327 @@
+/**
+ *  @file  rtems/score/schedulercbs.h
+ *
+ *  This include file contains all the constants and structures associated
+ *  with the manipulation of threads for the CBS scheduler.
+ */
+
+/*
+ *  Copryight (c) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#ifndef _RTEMS_SCORE_SCHEDULERCBS_H
+#define _RTEMS_SCORE_SCHEDULERCBS_H
+
+#include <rtems/score/chain.h>
+#include <rtems/score/priority.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/rbtree.h>
+#include <rtems/score/scheduleredf.h>
+#include <rtems/rtems/signal.h>
+#include <rtems/rtems/timer.h>
+#include <rtems/score/thread.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ *  @addtogroup ScoreScheduler
+ *
+ */
+/**@{*/
+
+/**
+ *  Entry points for the Constant Bandwidth Server Scheduler.
+ *
+ *  @note: The CBS scheduler is an enhancement of EDF scheduler,
+ *         therefor some routines are similar.
+ */
+#define SCHEDULER_CBS_ENTRY_POINTS \
+  { \
+    _Scheduler_EDF_Initialize,       /* initialize entry point */ \
+    _Scheduler_EDF_Schedule,         /* schedule entry point */ \
+    _Scheduler_EDF_Yield,            /* yield entry point */ \
+    _Scheduler_EDF_Block,            /* block entry point */ \
+    _Scheduler_CBS_Unblock,          /* unblock entry point */ \
+    _Scheduler_EDF_Allocate,         /* allocate entry point */ \
+    _Scheduler_EDF_Free,             /* free entry point */ \
+    _Scheduler_EDF_Update,           /* update entry point */ \
+    _Scheduler_EDF_Enqueue,          /* enqueue entry point */ \
+    _Scheduler_EDF_Enqueue_first,    /* enqueue_first entry point */ \
+    _Scheduler_EDF_Extract,          /* extract entry point */ \
+    _Scheduler_EDF_Priority_compare, /* compares two priorities */ \
+    _Scheduler_CBS_Release_job,      /* new period of task */ \
+    _Scheduler_priority_Tick         /* tick entry point */ \
+  }
+
+/* Return values for CBS server. */
+#define SCHEDULER_CBS_OK                        0
+#define SCHEDULER_CBS_ERROR_GENERIC            -16
+#define SCHEDULER_CBS_ERROR_NO_MEMORY          -17
+#define SCHEDULER_CBS_ERROR_INVALID_PARAMETER  -18
+#define SCHEDULER_CBS_ERROR_UNAUTHORIZED       -19
+#define SCHEDULER_CBS_ERROR_UNIMPLEMENTED      -20
+#define SCHEDULER_CBS_ERROR_MISSING_COMPONENT  -21
+#define SCHEDULER_CBS_ERROR_INCONSISTENT_STATE -22
+#define SCHEDULER_CBS_ERROR_SYSTEM_OVERLOAD    -23
+#define SCHEDULER_CBS_ERROR_INTERNAL_ERROR     -24
+#define SCHEDULER_CBS_ERROR_NOT_FOUND          -25
+#define SCHEDULER_CBS_ERROR_FULL               -26
+#define SCHEDULER_CBS_ERROR_EMPTY              -27
+#define SCHEDULER_CBS_ERROR_NOSERVER           SCHEDULER_CBS_ERROR_NOT_FOUND
+
+/** Maximum number of simultaneous servers. */
+extern uint32_t _Scheduler_CBS_Maximum_servers;
+
+/** Server id. */
+typedef uint32_t Scheduler_CBS_Server_id;
+
+/** Callback function invoked when a budget overrun of a task occurs. */
+typedef void (*Scheduler_CBS_Budget_overrun)(
+    Scheduler_CBS_Server_id server_id
+);
+
+/**
+ * This structure handles server parameters.
+ */
+typedef struct {
+  /** Relative deadline of the server. */
+  time_t deadline;
+  /** Budget (computation time) of the server. */
+  time_t budget;
+} Scheduler_CBS_Parameters;
+
+/**
+ * This structure represents a time server.
+ */
+typedef struct {
+  /**
+   * Task id.
+   *
+   * @note: The current implementation of CBS handles only one task per server.
+   */
+  rtems_id                 task_id;
+  /** Server paramenters. */
+  Scheduler_CBS_Parameters parameters;
+  /** Callback function invoked when a budget overrun occurs. */
+  Scheduler_CBS_Budget_overrun  cbs_budget_overrun;
+} Scheduler_CBS_Server;
+
+/**
+ * This structure handles CBS specific data of a thread.
+ */
+typedef struct {
+  /** EDF scheduler specific data of a task. */
+  Scheduler_EDF_Per_thread      edf_per_thread;
+  /** CBS server specific data of a task. */
+  Scheduler_CBS_Server         *cbs_server;
+} Scheduler_CBS_Per_thread;
+
+
+/**
+ * List of servers. The @a Scheduler_CBS_Server is the index to the array
+ * of pointers to @a _Scheduler_CBS_Server_list.
+ */
+Scheduler_CBS_Server **_Scheduler_CBS_Server_list;
+
+/**
+ *  @brief Scheduler CBS Unblock
+ *
+ *  This routine adds @a the_thread to the scheduling decision, that is,
+ *  adds it to the ready queue and updates any appropriate scheduling
+ *  variables, for example the heir thread.
+ *
+ *  It is checked whether the remaining budget is sufficient. If not, the
+ *  thread continues as a new job in order to protect concurrent threads.
+ *
+ *  @note This has to be asessed as missed deadline of the current job.
+ *
+ *  @param[in] the_thread will be unblocked.
+ */
+void _Scheduler_CBS_Unblock(
+  Thread_Control    *the_thread
+);
+
+/**
+ *  @brief Scheduler CBS Release job
+ *
+ *  This routine is called when a new job of task is released.
+ *  It is called only from Rate Monotonic manager in the beginning
+ *  of new period. Deadline has to be shifted and budget replenished.
+ *
+ *  @param[in] the_thread is the owner of the job.
+ *  @param[in] length of the new job from now. If equal to 0,
+ *             the job was cancelled or deleted.
+ */
+
+void _Scheduler_CBS_Release_job (
+  Thread_Control  *the_thread,
+  uint32_t         length
+);
+
+/**
+ *  @brief _Scheduler_CBS_Initialize
+ *
+ *  Initializes the CBS library.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Initialize(void);
+
+/**
+ *  @brief _Scheduler_CBS_Attach_thread
+ *
+ *  Attach a task to an already existing server.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Attach_thread (
+  Scheduler_CBS_Server_id server_id,
+  rtems_id                task_id
+);
+
+/**
+ *  @brief _Scheduler_CBS_Detach_thread
+ *
+ *  Detach from the CBS Server.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Detach_thread (
+  Scheduler_CBS_Server_id server_id,
+  rtems_id                task_id
+);
+
+/**
+ *  @brief _Scheduler_CBS_Cleanup
+ *
+ *  Cleanup resources associated to the CBS Library.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Cleanup (void);
+
+/**
+ *  @brief _Scheduler_CBS_Create_server
+ *
+ *  Create a new server with specified parameters.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Create_server (
+  Scheduler_CBS_Parameters     *params,
+  Scheduler_CBS_Budget_overrun  budget_overrun_callback,
+  rtems_id                     *server_id
+);
+
+/**
+ *  @brief _Scheduler_CBS_Destroy_server
+ *
+ *  Detach all tasks from a server and destroy it.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Destroy_server (
+  Scheduler_CBS_Server_id server_id
+);
+
+/**
+ *  @brief _Scheduler_CBS_Get_approved_budget
+ *
+ *  Retrieve the budget that has been approved for the subsequent
+ *  server instances.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Get_approved_budget (
+  Scheduler_CBS_Server_id  server_id,
+  time_t                  *approved_budget
+);
+
+/**
+ *  @brief _Scheduler_CBS_Get_remaining_budget
+ *
+ *  Retrieve remaining budget for the current server instance.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Get_remaining_budget (
+  Scheduler_CBS_Server_id  server_id,
+  time_t                  *remaining_budget
+);
+
+/**
+ *  @brief _Scheduler_CBS_Get_execution_time
+ *
+ *  Retrieve time info relative to the current server.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Get_execution_time (
+  Scheduler_CBS_Server_id   server_id,
+  time_t                   *exec_time,
+  time_t                   *abs_time
+);
+
+/**
+ *  @brief _Scheduler_CBS_Get_parameters
+ *
+ *  Retrieve CBS scheduling parameters.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Get_parameters (
+  Scheduler_CBS_Server_id   server_id,
+  Scheduler_CBS_Parameters *params
+);
+
+/**
+ *  @brief _Scheduler_CBS_Get_server_id
+ *
+ *  Get a thread server id, or SCHEDULER_CBS_ERROR_NOT_FOUND if it is not
+ *  attached to any server.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Get_server_id (
+  rtems_id                 task_id,
+  Scheduler_CBS_Server_id *server_id
+);
+
+/**
+ *  @brief _Scheduler_CBS_Set_parameters
+ *
+ *  Change CBS scheduling parameters.
+ *
+ *  @return status code.
+ */
+int _Scheduler_CBS_Set_parameters (
+  Scheduler_CBS_Server_id   server_id,
+  Scheduler_CBS_Parameters *parameters
+);
+
+/**
+ *  @brief Scheduler CBS Budget overrun
+ *
+ *  This routine is invoked when a limited time quantum is exceeded.
+ */
+void _Scheduler_CBS_Budget_callout(
+  Thread_Control *the_thread
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+/**@}*/
+
+#endif
+/* end of include file */
diff --git a/cpukit/score/preinstall.am b/cpukit/score/preinstall.am
index 0461648517..09c6fa93ac 100644
--- a/cpukit/score/preinstall.am
+++ b/cpukit/score/preinstall.am
@@ -127,6 +127,10 @@ $(PROJECT_INCLUDE)/rtems/score/scheduler.h: include/rtems/score/scheduler.h $(PR
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/score/scheduler.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/score/scheduler.h
 
+$(PROJECT_INCLUDE)/rtems/score/schedulercbs.h: include/rtems/score/schedulercbs.h $(PROJECT_INCLUDE)/rtems/score/$(dirstamp)
+	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/score/schedulercbs.h
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/score/schedulercbs.h
+
 $(PROJECT_INCLUDE)/rtems/score/scheduleredf.h: include/rtems/score/scheduleredf.h $(PROJECT_INCLUDE)/rtems/score/$(dirstamp)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/rtems/score/scheduleredf.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/rtems/score/scheduleredf.h
diff --git a/cpukit/score/src/schedulercbs.c b/cpukit/score/src/schedulercbs.c
new file mode 100644
index 0000000000..dba4925b8d
--- /dev/null
+++ b/cpukit/score/src/schedulercbs.c
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+#include <rtems/rtems/signal.h>
+
+void _Scheduler_CBS_Budget_callout(
+  Thread_Control *the_thread
+)
+{
+  Priority_Control          new_priority;
+  Scheduler_CBS_Per_thread *sched_info;
+  Scheduler_CBS_Server_id   server_id;
+
+  /* Put violating task to background until the end of period. */
+  new_priority = the_thread->Start.initial_priority;
+  if ( the_thread->real_priority != new_priority )
+    the_thread->real_priority = new_priority;
+  if ( the_thread->current_priority != new_priority )
+    _Thread_Change_priority(the_thread, new_priority, true);
+
+  /* Invoke callback function if any. */
+  sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+  if ( sched_info->cbs_server->cbs_budget_overrun ) {
+    _Scheduler_CBS_Get_server_id(
+        sched_info->cbs_server->task_id,
+        &server_id
+    );
+    sched_info->cbs_server->cbs_budget_overrun( server_id );
+  }
+}
+
+int _Scheduler_CBS_Initialize(void)
+{
+  unsigned int i;
+  _Scheduler_CBS_Server_list = (Scheduler_CBS_Server **) _Workspace_Allocate(
+      _Scheduler_CBS_Maximum_servers * sizeof(Scheduler_CBS_Server*) );
+  if ( !_Scheduler_CBS_Server_list )
+    return SCHEDULER_CBS_ERROR_NO_MEMORY;
+  for (i = 0; i<_Scheduler_CBS_Maximum_servers; i++) {
+    _Scheduler_CBS_Server_list[i] = NULL;
+  }
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsattachthread.c b/cpukit/score/src/schedulercbsattachthread.c
new file mode 100644
index 0000000000..7796f12a6b
--- /dev/null
+++ b/cpukit/score/src/schedulercbsattachthread.c
@@ -0,0 +1,63 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+#include <rtems/rtems/object.h>
+
+int _Scheduler_CBS_Attach_thread (
+  Scheduler_CBS_Server_id server_id,
+  rtems_id                task_id
+)
+{
+  Objects_Locations location;
+  Thread_Control *the_thread;
+  Scheduler_CBS_Per_thread *sched_info;
+
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  the_thread = _Thread_Get(task_id, &location);
+  /* The routine _Thread_Get may disable dispatch and not enable again. */
+  if ( the_thread )
+    _Thread_Enable_dispatch();
+  if ( !the_thread )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+
+  /* Thread is already attached to a server. */
+  if ( sched_info->cbs_server )
+    return SCHEDULER_CBS_ERROR_FULL;
+
+  /* Server is not valid. */
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+
+  /* Server is already attached to a thread. */
+  if ( _Scheduler_CBS_Server_list[server_id]->task_id != -1 )
+    return SCHEDULER_CBS_ERROR_FULL;
+
+  _Scheduler_CBS_Server_list[server_id]->task_id = task_id;
+  sched_info->cbs_server = (void *) _Scheduler_CBS_Server_list[server_id];
+
+  the_thread->budget_callout   = _Scheduler_CBS_Budget_callout;
+  the_thread->budget_algorithm = THREAD_CPU_BUDGET_ALGORITHM_CALLOUT;
+  the_thread->is_preemptible   = true;
+
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbscleanup.c b/cpukit/score/src/schedulercbscleanup.c
new file mode 100644
index 0000000000..c6c0b94129
--- /dev/null
+++ b/cpukit/score/src/schedulercbscleanup.c
@@ -0,0 +1,31 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Cleanup (void)
+{
+  unsigned int i;
+
+  for ( i = 0; i<_Scheduler_CBS_Maximum_servers; i++ ) {
+    if ( _Scheduler_CBS_Server_list[ i ] )
+      _Scheduler_CBS_Destroy_server( i );
+  }
+  _Workspace_Free( _Scheduler_CBS_Server_list );
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbscreateserver.c b/cpukit/score/src/schedulercbscreateserver.c
new file mode 100644
index 0000000000..c604423d50
--- /dev/null
+++ b/cpukit/score/src/schedulercbscreateserver.c
@@ -0,0 +1,55 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Create_server (
+  Scheduler_CBS_Parameters     *params,
+  Scheduler_CBS_Budget_overrun  budget_overrun_callback,
+  rtems_id                     *server_id
+)
+{
+  unsigned int i;
+  Scheduler_CBS_Server *the_server;
+
+  if ( params->budget <= 0 ||
+       params->deadline <= 0 ||
+       params->budget >= SCHEDULER_EDF_PRIO_MSB ||
+       params->deadline >= SCHEDULER_EDF_PRIO_MSB )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  for ( i = 0; i<_Scheduler_CBS_Maximum_servers; i++ ) {
+    if ( !_Scheduler_CBS_Server_list[i] )
+      break;
+  }
+
+  if ( i == _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_FULL;
+
+  *server_id = i;
+  _Scheduler_CBS_Server_list[*server_id] = (Scheduler_CBS_Server *)
+    _Workspace_Allocate( sizeof(Scheduler_CBS_Server) );
+  the_server = _Scheduler_CBS_Server_list[*server_id];
+  if ( !the_server )
+    return SCHEDULER_CBS_ERROR_NO_MEMORY;
+
+  the_server->parameters = *params;
+  the_server->task_id = -1;
+  the_server->cbs_budget_overrun = budget_overrun_callback;
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsdestroyserver.c b/cpukit/score/src/schedulercbsdestroyserver.c
new file mode 100644
index 0000000000..85867cf7dc
--- /dev/null
+++ b/cpukit/score/src/schedulercbsdestroyserver.c
@@ -0,0 +1,40 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Destroy_server (
+  Scheduler_CBS_Server_id server_id
+)
+{
+  int ret = SCHEDULER_CBS_OK;
+  rtems_id tid;
+
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+
+  if ( (tid = _Scheduler_CBS_Server_list[server_id]->task_id) != -1 )
+    ret = _Scheduler_CBS_Detach_thread ( server_id, tid );
+
+  _Workspace_Free( _Scheduler_CBS_Server_list[server_id] );
+  _Scheduler_CBS_Server_list[server_id] = NULL;
+  return ret;
+}
diff --git a/cpukit/score/src/schedulercbsdetachthread.c b/cpukit/score/src/schedulercbsdetachthread.c
new file mode 100644
index 0000000000..65aa88dd8f
--- /dev/null
+++ b/cpukit/score/src/schedulercbsdetachthread.c
@@ -0,0 +1,56 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Detach_thread (
+  Scheduler_CBS_Server_id server_id,
+  rtems_id                task_id
+)
+{
+  Objects_Locations location;
+  Thread_Control *the_thread;
+  Scheduler_CBS_Per_thread *sched_info;
+
+  the_thread = _Thread_Get(task_id, &location);
+  /* The routine _Thread_Get may disable dispatch and not enable again. */
+  if ( the_thread ) {
+    _Thread_Enable_dispatch();
+    sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+  }
+
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  if ( !the_thread )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  /* Server is not valid. */
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+  /* Thread and server are not attached. */
+  if ( _Scheduler_CBS_Server_list[server_id]->task_id != task_id )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  _Scheduler_CBS_Server_list[server_id]->task_id = -1;
+  sched_info->cbs_server = NULL;
+
+  the_thread->budget_algorithm = the_thread->Start.budget_algorithm;
+  the_thread->budget_callout   = the_thread->Start.budget_callout;
+  the_thread->is_preemptible   = the_thread->Start.is_preemptible;
+
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsgetapprovedbudget.c b/cpukit/score/src/schedulercbsgetapprovedbudget.c
new file mode 100644
index 0000000000..14db13031f
--- /dev/null
+++ b/cpukit/score/src/schedulercbsgetapprovedbudget.c
@@ -0,0 +1,33 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Get_approved_budget (
+  Scheduler_CBS_Server_id  server_id,
+  time_t                  *approved_budget
+)
+{
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+
+  *approved_budget = _Scheduler_CBS_Server_list[server_id]->parameters.budget;
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsgetexecutiontime.c b/cpukit/score/src/schedulercbsgetexecutiontime.c
new file mode 100644
index 0000000000..b8d92ada30
--- /dev/null
+++ b/cpukit/score/src/schedulercbsgetexecutiontime.c
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Get_execution_time (
+  Scheduler_CBS_Server_id   server_id,
+  time_t                   *exec_time,
+  time_t                   *abs_time
+)
+{
+  Objects_Locations location;
+  Thread_Control *the_thread;
+
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+  if ( !_Scheduler_CBS_Server_list[server_id]->task_id ) {
+    *exec_time = 0;
+    return SCHEDULER_CBS_OK;
+  }
+
+  the_thread = _Thread_Get(
+                 _Scheduler_CBS_Server_list[server_id]->task_id,
+                 &location
+               );
+  /* The routine _Thread_Get may disable dispatch and not enable again. */
+  if ( the_thread ) {
+    _Thread_Enable_dispatch();
+    *exec_time = _Scheduler_CBS_Server_list[server_id]->parameters.budget -
+      the_thread->cpu_time_budget;
+  }
+  else {
+    *exec_time = _Scheduler_CBS_Server_list[server_id]->parameters.budget;
+  }
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsgetparameters.c b/cpukit/score/src/schedulercbsgetparameters.c
new file mode 100644
index 0000000000..450afd0d68
--- /dev/null
+++ b/cpukit/score/src/schedulercbsgetparameters.c
@@ -0,0 +1,33 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Get_parameters (
+  Scheduler_CBS_Server_id   server_id,
+  Scheduler_CBS_Parameters *params
+)
+{
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+
+  *params = _Scheduler_CBS_Server_list[server_id]->parameters;
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsgetremainingbudget.c b/cpukit/score/src/schedulercbsgetremainingbudget.c
new file mode 100644
index 0000000000..664c7e1bc4
--- /dev/null
+++ b/cpukit/score/src/schedulercbsgetremainingbudget.c
@@ -0,0 +1,52 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Get_remaining_budget (
+  Scheduler_CBS_Server_id  server_id,
+  time_t                  *remaining_budget
+)
+{
+  Objects_Locations location;
+  Thread_Control *the_thread;
+
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+  if ( _Scheduler_CBS_Server_list[server_id]->task_id == -1 ) {
+    *remaining_budget = _Scheduler_CBS_Server_list[server_id]->parameters.budget;
+    return SCHEDULER_CBS_OK;
+  }
+
+  the_thread = _Thread_Get(
+                 _Scheduler_CBS_Server_list[server_id]->task_id,
+                 &location
+               );
+  /* The routine _Thread_Get may disable dispatch and not enable again. */
+  if ( the_thread ) {
+    _Thread_Enable_dispatch();
+    *remaining_budget = the_thread->cpu_time_budget;
+  }
+  else {
+    *remaining_budget = 0;
+  }
+
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsgetserverid.c b/cpukit/score/src/schedulercbsgetserverid.c
new file mode 100644
index 0000000000..1460b0c058
--- /dev/null
+++ b/cpukit/score/src/schedulercbsgetserverid.c
@@ -0,0 +1,35 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Get_server_id (
+  rtems_id                 task_id,
+  Scheduler_CBS_Server_id *server_id
+)
+{
+  unsigned int i;
+  for ( i = 0; i<_Scheduler_CBS_Maximum_servers; i++ ) {
+    if ( _Scheduler_CBS_Server_list[i] &&
+         _Scheduler_CBS_Server_list[i]->task_id == task_id ) {
+      *server_id = i;
+      return SCHEDULER_CBS_OK;
+    }
+  }
+  return SCHEDULER_CBS_ERROR_NOSERVER;
+}
diff --git a/cpukit/score/src/schedulercbsreleasejob.c b/cpukit/score/src/schedulercbsreleasejob.c
new file mode 100644
index 0000000000..c64b60ffb1
--- /dev/null
+++ b/cpukit/score/src/schedulercbsreleasejob.c
@@ -0,0 +1,52 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+void _Scheduler_CBS_Release_job(
+  Thread_Control    *the_thread,
+  uint32_t           deadline
+)
+{
+  Priority_Control new_priority;
+  Scheduler_CBS_Per_thread *sched_info =
+    (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+  Scheduler_CBS_Server *serv_info =
+    (Scheduler_CBS_Server *) sched_info->cbs_server;
+
+  if (deadline) {
+    /* Initializing or shifting deadline. */
+    if (serv_info && serv_info->parameters.budget)
+      new_priority = (_Watchdog_Ticks_since_boot + serv_info->parameters.deadline)
+        & ~SCHEDULER_EDF_PRIO_MSB;
+    else
+      new_priority = (_Watchdog_Ticks_since_boot + deadline)
+        & ~SCHEDULER_EDF_PRIO_MSB;
+  }
+  else {
+    /* Switch back to background priority. */
+    new_priority = the_thread->Start.initial_priority;
+  }
+
+  /* Budget replenishment for the next job. */
+  if (serv_info && serv_info->parameters.budget)
+    the_thread->cpu_time_budget = serv_info->parameters.budget;
+
+  the_thread->real_priority = new_priority;
+  _Thread_Change_priority(the_thread, new_priority, true);
+}
diff --git a/cpukit/score/src/schedulercbssetparameters.c b/cpukit/score/src/schedulercbssetparameters.c
new file mode 100644
index 0000000000..4268110364
--- /dev/null
+++ b/cpukit/score/src/schedulercbssetparameters.c
@@ -0,0 +1,40 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/config.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+int _Scheduler_CBS_Set_parameters (
+  Scheduler_CBS_Server_id   server_id,
+  Scheduler_CBS_Parameters *params
+)
+{
+  if ( server_id < 0 || server_id >= _Scheduler_CBS_Maximum_servers )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  if ( params->budget <= 0 ||
+       params->deadline <= 0 ||
+       params->budget >= SCHEDULER_EDF_PRIO_MSB ||
+       params->deadline >= SCHEDULER_EDF_PRIO_MSB )
+    return SCHEDULER_CBS_ERROR_INVALID_PARAMETER;
+
+  if ( !_Scheduler_CBS_Server_list[server_id] )
+    return SCHEDULER_CBS_ERROR_NOSERVER;
+
+  _Scheduler_CBS_Server_list[server_id]->parameters = *params;
+  return SCHEDULER_CBS_OK;
+}
diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
new file mode 100644
index 0000000000..0f417d8c9e
--- /dev/null
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (C) 2011 Petr Benes.
+ *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ *  $Id$
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulercbs.h>
+
+void _Scheduler_CBS_Unblock(
+  Thread_Control    *the_thread
+)
+{
+  Scheduler_CBS_Per_thread *sched_info;
+  Scheduler_CBS_Server *serv_info;
+  Priority_Control new_priority;
+
+  _Scheduler_EDF_Enqueue(the_thread);
+  /* TODO: flash critical section? */
+
+  sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
+  serv_info = (Scheduler_CBS_Server *) sched_info->cbs_server;
+
+  /*
+   * Late unblock rule for deadline-driven tasks. The remaining time to
+   * deadline must be sufficient to serve the remaining computation time
+   * without increased utilization of this task. It might cause a deadline
+   * miss of another task.
+   */
+  if (serv_info) {
+    time_t deadline = serv_info->parameters.deadline;
+    time_t budget = serv_info->parameters.budget;
+    time_t deadline_left = the_thread->cpu_time_budget;
+    time_t budget_left = the_thread->real_priority -
+                           _Watchdog_Ticks_since_boot;
+
+    if ( deadline*budget_left > budget*deadline_left ) {
+      /* Put late unblocked task to background until the end of period. */
+      new_priority = the_thread->Start.initial_priority;
+      if ( the_thread->real_priority != new_priority )
+        the_thread->real_priority = new_priority;
+      if ( the_thread->current_priority != new_priority )
+        _Thread_Change_priority(the_thread, new_priority, true);
+    }
+  }
+
+  /*
+   *  If the thread that was unblocked is more important than the heir,
+   *  then we have a new heir.  This may or may not result in a
+   *  context switch.
+   *
+   *  Normal case:
+   *    If the current thread is preemptible, then we need to do
+   *    a context switch.
+   *  Pseudo-ISR case:
+   *    Even if the thread isn't preemptible, if the new heir is
+   *    a pseudo-ISR system task, we need to do a context switch.
+   */
+  if ( _Scheduler_Is_priority_higher_than( the_thread->current_priority,
+       _Thread_Heir->current_priority)) {
+    _Thread_Heir = the_thread;
+    if ( _Thread_Executing->is_preemptible ||
+         the_thread->current_priority == 0 )
+      _Thread_Dispatch_necessary = true;
+  }
+}