bsps/lm32: Move shared drivers to bsps

This patch is a part of the BSP source reorganization.

Update #3285.

bsps/lm32/shared/milkymist_timer/timer.c

@@ -0,0 +1,78 @@
+/*  timer.c
+ *
+ *  This file manages the benchmark timer used by the RTEMS Timing
+ *  Test Suite.  Each measured time period is demarcated by calls to
+ *  benchmark_timer_initialize() and benchmark_timer_read().
+ *  benchmark_timer_read() usually returns the number of microseconds
+ *  since benchmark_timer_initialize() exitted.
+ *
+ *  NOTE: It is important that the timer start/stop overhead be
+ *        determined when porting or modifying this code.
+ *
+ *  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.
+ *
+ *  COPYRIGHT (c) Yann Sionneau <yann.sionneau@telecom-sudparis.eu> (GSoC 2010)
+ *  Telecom SudParis
+ */
+
+#include <rtems.h>
+#include <bsp.h>
+#include <rtems/btimer.h>
+#include <rtems/bspIo.h>
+#include "../include/system_conf.h"
+#include "../../shared/clock/clock.h"
+
+bool benchmark_timer_find_average_overhead;
+
+void benchmark_timer_initialize(void)
+{
+  MM_WRITE(MM_TIMER1_COMPARE, 0xffffffff);
+  MM_WRITE(MM_TIMER1_COUNTER, 0);
+  MM_WRITE(MM_TIMER1_CONTROL, TIMER_ENABLE);
+}
+
+/*
+ *  The following controls the behavior of benchmark_timer_read().
+ *
+ *  AVG_OVEREHAD is the overhead for starting and stopping the timer.  It
+ *  is usually deducted from the number returned.
+ *
+ *  LEAST_VALID is the lowest number this routine should trust.  Numbers
+ *  below this are "noise" and zero is returned.
+ */
+
+#define AVG_OVERHEAD      4  /* It typically takes X.X microseconds */
+                             /* (Y countdowns) to start/stop the timer. */
+                             /* This value is in microseconds. */
+#define LEAST_VALID       4  /* Don't trust a clicks value lower than this */
+
+benchmark_timer_t benchmark_timer_read(void)
+{
+  uint32_t ticks;
+  uint32_t total;
+
+  ticks = MM_READ(MM_TIMER1_COUNTER);
+  if (ticks == 0xffffffff)
+    printk("Timer overflow!\n");
+
+  total = ticks / (MM_READ(MM_FREQUENCY) / 1000000);
+
+  if (benchmark_timer_find_average_overhead)
+    return total;
+  else
+  {
+    if (total < LEAST_VALID)
+      return 0;
+
+    return (total - AVG_OVERHEAD);
+  }
+}
+
+void benchmark_timer_disable_subtracting_average_overhead(
+  bool find_flag
+)
+{
+  benchmark_timer_find_average_overhead = find_flag;
+}