bsps: Move benchmark timer to bsps

This patch is a part of the BSP source reorganization.

Update #3285.

bsps/sparc/erc32/btimer/btimer.c

@@ -0,0 +1,81 @@
+/*  timer.c
+ *
+ *  This file implements a benchmark timer using the General Purpose Timer on
+ *  the MEC.
+ *
+ *  COPYRIGHT (c) 1989-1999.
+ *  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.org/license/LICENSE.
+ *
+ *  Ported to ERC32 implementation of the SPARC by On-Line Applications
+ *  Research Corporation (OAR) under contract to the European Space
+ *  Agency (ESA).
+ *
+ *  ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995.
+ *  European Space Agency.
+ */
+
+#include <bsp.h>
+#include <rtems/btimer.h>
+
+bool benchmark_timer_find_average_overhead;
+
+bool benchmark_timer_is_initialized = false;
+
+void benchmark_timer_initialize(void)
+{
+  /*
+   *  Timer runs long and accurate enough not to require an interrupt.
+   */
+
+  if ( benchmark_timer_is_initialized == false ) {
+
+    /* approximately 1 us per countdown */
+    ERC32_MEC.General_Purpose_Timer_Scalar  = CLOCK_SPEED - 1;
+    ERC32_MEC.General_Purpose_Timer_Counter = 0xffffffff;
+
+  } else {
+    benchmark_timer_is_initialized = true;
+  }
+
+  ERC32_MEC_Set_General_Purpose_Timer_Control(
+    ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING |
+      ERC32_MEC_TIMER_COUNTER_LOAD_COUNTER
+  );
+
+  ERC32_MEC_Set_General_Purpose_Timer_Control(
+    ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING
+  );
+
+}
+
+#define AVG_OVERHEAD     12  /* It typically takes 3.0 microseconds */
+                             /*     to start/stop the timer. */
+#define LEAST_VALID      13  /* Don't trust a value lower than this */
+
+benchmark_timer_t benchmark_timer_read(void)
+{
+  uint32_t          total;
+
+  total = ERC32_MEC.General_Purpose_Timer_Counter;
+
+  total = 0xffffffff - total;
+
+  if ( benchmark_timer_find_average_overhead == true )
+    return total;          /* in one microsecond units */
+
+  if ( total < LEAST_VALID )
+    return 0;            /* below timer resolution */
+
+  return total - AVG_OVERHEAD;
+}
+
+void benchmark_timer_disable_subtracting_average_overhead(
+  bool find_flag
+)
+{
+  benchmark_timer_find_average_overhead = find_flag;
+}