new file for MIPS port by Craig Lebakken (lebakken@minn.net) and

Derrick Ostertag (ostertag@transition.com).
1996-09-06 18:11:41 +00:00
parent f29032c587
commit f198c63d6a
71 changed files with 16850 additions and 0 deletions
--- a/c/src/lib/libcpu/mips/timer/timer.c
+++ b/c/src/lib/libcpu/mips/timer/timer.c
@@ -0,0 +1,136 @@
+/*  timer.c
+ *
+ *  This file contains the initialization code for the IDT 4650 timer driver.
+ *
+ *  Author:     Craig Lebakken <craigl@transition.com>
+ *
+ *  COPYRIGHT (c) 1996 by Transition Networks Inc.
+ *
+ *  To anyone who acknowledges that this file is provided "AS IS"
+ *  without any express or implied warranty:
+ *      permission to use, copy, modify, and distribute this file
+ *      for any purpose is hereby granted without fee, provided that
+ *      the above copyright notice and this notice appears in all
+ *      copies, and that the name of Transition Networks not be used in
+ *      advertising or publicity pertaining to distribution of the
+ *      software without specific, written prior permission.
+ *      Transition Networks makes no representations about the suitability
+ *      of this software for any purpose.
+ *
+ *  derived from src/lib/libbsp/no_cpu/no_bsp/timer/timer.c
+ *
+ *  This file manages the benchmark timer used by the RTEMS Timing Test
+ *  Suite.  Each measured time period is demarcated by calls to
+ *  Timer_initialize() and Read_timer().  Read_timer() usually returns
+ *  the number of microseconds since Timer_initialize() exitted.
+ *
+ *  NOTE: It is important that the timer start/stop overhead be
+ *        determined when porting or modifying this code.
+ *
+ *  COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
+ *  On-Line Applications Research Corporation (OAR).
+ *  All rights assigned to U.S. Government, 1994.
+ *
+ *  This material may be reproduced by or for the U.S. Government pursuant
+ *  to the copyright license under the clause at DFARS 252.227-7013.  This
+ *  notice must appear in all copies of this file and its derivatives.
+ *
+ *  timer.c,v 1.2 1995/05/31 16:56:39 joel Exp
+ */
+
+#ifndef lint
+static char _sccsid[] = "@(#)timer.c 08/20/96     1.5\n";
+#endif
+
+#include <rtems.h>
+#include <bsp.h>
+
+#define CLOCKS_PER_MICROSECOND ( CPU_CLOCK_RATE_MHZ )
+#define TIMER_MAX_VALUE 0xffffffff
+
+extern unsigned32 mips_read_timer( void );
+
+static rtems_boolean Timer_driver_Find_average_overhead;
+static unsigned32 Timer_initial_value = 0;
+
+void Timer_initialize( void )
+{
+   Timer_initial_value = mips_read_timer();
+  /*
+   *  Somehow start the timer
+   */
+
+  /* Timer on 4650 is always running */
+}
+
+/*
+ *  The following controls the behavior of Read_timer().
+ *
+ *  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      8  /* It typically takes X.X microseconds */
+                             /* (Y countdowns) to start/stop the timer. */
+                             /* This value is in cycles. */
+#define LEAST_VALID       1  /* Don't trust a clicks value lower than this */
+
+int Read_timer( void )
+{
+  unsigned64 clicks;
+  unsigned32 total;
+
+  /*
+   *  Read the timer and see how many clicks it has been since we started.
+   */
+
+  clicks = mips_read_timer();   /* XXX: read some HW here */
+  if (clicks < Timer_initial_value)
+  {
+      clicks += TIMER_MAX_VALUE;
+  }
+  clicks -= Timer_initial_value;
+
+  /*
+   *  Total is calculated by taking into account the number of timer overflow
+   *  interrupts since the timer was initialized and clicks since the last
+   *  interrupts.
+   */
+#if 0 /* leave total in number of cycles */
+   total = clicks / CLOCKS_PER_MICROSECOND;
+#else
+   total = clicks;
+#endif
+
+  if ( Timer_driver_Find_average_overhead == 1 )
+    return total;          /* in # cycles units */
+  else {
+    if ( total < LEAST_VALID )
+      return 0;            /* below timer resolution */
+  /*
+   *  leave total in cycles
+   */
+      return (total - AVG_OVERHEAD);
+    }
+}
+
+/*
+ *  Empty function call used in loops to measure basic cost of looping
+ *  in Timing Test Suite.
+ */
+
+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;
+}
+