bsps: Move benchmark timer to bsps

This patch is a part of the BSP source reorganization.

Update #3285.

bsps/mips/csb350/btimer/btimer.c

@@ -0,0 +1,57 @@
+/*
+ *  This file implements a benchmark timer using the count/compare
+ *  CP0 registers.
+ *
+ *  Copyright (c) 2005 by Cogent Computer Systems
+ *  Written by Jay Monkman <jtm@lopingdog.com>
+ *
+ *  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.
+ */
+
+#include <assert.h>
+
+#include <bsp.h>
+#include <rtems/btimer.h>
+
+bool benchmark_timer_find_average_overhead;
+uint32_t tstart;
+
+void benchmark_timer_initialize(void)
+{
+    __asm__ volatile ("mfc0 %0, $9\n" : "=r" (tstart));
+    /* tick time in picooseconds */
+}
+
+#define AVG_OVERHEAD      0  /* It typically takes N instructions */
+                             /*     to start/stop the timer. */
+#define LEAST_VALID       1  /* Don't trust a value lower than this */
+                             /* tx39 simulator can count instructions. :) */
+
+benchmark_timer_t benchmark_timer_read(void)
+{
+  uint32_t  total;
+  uint32_t  cnt;
+
+  __asm__ volatile ("mfc0 %0, $9\n" : "=r" (cnt));
+
+  total = cnt - tstart;
+  total = (total * 1000) / 396; /* convert to nanoseconds */
+
+
+  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;
+}