Backport from rtems-4-6-branch.

c/src/lib/libbsp/sparc/leon3/timer/timer.c

@@ -0,0 +1,82 @@
+/*  timer.c
+ *
+ *  This file implements a benchmark timer using timer 2.
+ *
+ *  COPYRIGHT (c) 1989-1998.
+ *  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.
+ *
+ *  Ported to LEON implementation of the SPARC by On-Line Applications
+ *  Research Corporation (OAR) under contract to the European Space 
+ *  Agency (ESA).
+ *
+ *  LEON modifications of respective RTEMS file: COPYRIGHT (c) 1995. 
+ *  European Space Agency.
+ *
+ *  $Id$
+ */
+
+
+#include <bsp.h>
+
+rtems_boolean Timer_driver_Find_average_overhead;
+
+rtems_boolean Timer_driver_Is_initialized = FALSE;
+
+extern volatile LEON3_Timer_Regs_Map *LEON3_Timer_Regs;
+
+void Timer_initialize()
+{
+  /*
+   *  Timer runs long and accurate enough not to require an interrupt.
+   */
+  if (LEON3_Timer_Regs) {
+    if ( Timer_driver_Is_initialized == FALSE ) {
+      /* approximately 1 us per countdown */
+      LEON3_Timer_Regs->reload_t1 = 0xffffff;
+      LEON3_Timer_Regs->value_t1 = 0xffffff;
+    } else {
+      Timer_driver_Is_initialized = TRUE;
+    }
+    LEON3_Timer_Regs->conf_t1 = LEON3_GPTIMER_EN | LEON3_GPTIMER_LD;
+  }
+}
+
+#define AVG_OVERHEAD      3  /* It typically takes 3.0 microseconds */
+                             /*     to start/stop the timer. */
+#define LEAST_VALID       2  /* Don't trust a value lower than this */
+
+int Read_timer()
+{
+  uint32_t  total;
+
+  if (LEON3_Timer_Regs) {
+    total = LEON3_Timer_Regs->value_t1;
+    
+    total = 0xffffff - total;
+    
+    if ( Timer_driver_Find_average_overhead == 1 )
+      return total;          /* in one microsecond units */
+    
+    if ( total < LEAST_VALID )
+      return 0;            /* below timer resolution */
+    
+    return total - AVG_OVERHEAD;
+  }
+  return 0;
+}
+
+rtems_status_code Empty_function( void )
+{
+  return RTEMS_SUCCESSFUL;
+}
+
+void Set_find_average_overhead(
+  rtems_boolean find_flag
+)
+{
+  Timer_driver_Find_average_overhead = find_flag;
+}