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-rw-r--r--c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c b/c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c
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index 0000000000..50c2a3e00a
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+++ b/c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c
@@ -0,0 +1,104 @@
+/* timer.c
+ *
+ * This file manages the interval timer on the PowerPC MPC8xx.
+ * NOTE: This is not the PIT, but rather the RTEMS interval
+ * timer
+ * We shall use the bottom 32 bits of the timebase register,
+ *
+ * The following was in the 403 version of this file. I don't
+ * know what it means. JTM 5/19/98
+ * NOTE: It is important that the timer start/stop overhead be
+ * determined when porting or modifying this code.
+ *
+ * Author: Jay Monkman (jmonkman@frasca.com)
+ * Copywright (C) 1998 by Frasca International, Inc.
+ *
+ * Derived from c/src/lib/libcpu/ppc/ppc403/timer/timer.c:
+ *
+ * Author: Andrew Bray <andy@i-cubed.co.uk>
+ *
+ * COPYRIGHT (c) 1995 by i-cubed ltd.
+ *
+ * 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 i-cubed limited not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * i-cubed limited makes no representations about the suitability
+ * of this software for any purpose.
+ *
+ * Derived from c/src/lib/libcpu/hppa1_1/timer/timer.c:
+ *
+ * COPYRIGHT (c) 1989-1998.
+ * On-Line Applications Research Corporation (OAR).
+ * Copyright assigned to U.S. Government, 1994.
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.OARcorp.com/rtems/license.html.
+ *
+ * $Id$
+ */
+
+#include <bsp.h>
+#include <rtems.h>
+#include <mpc8xx.h>
+
+extern rtems_cpu_table Cpu_table; /* owned by BSP */
+
+static volatile rtems_unsigned32 Timer_starting;
+static rtems_boolean Timer_driver_Find_average_overhead;
+
+/*
+ * This is so small that this code will be reproduced where needed.
+ */
+static inline rtems_unsigned32 get_itimer(void)
+{
+ rtems_unsigned32 ret;
+
+ asm volatile ("mftb %0" : "=r" ((ret))); /* TBLO */
+
+ return ret;
+}
+
+void Timer_initialize(void)
+{
+ /* set interrupt level and enable timebase. This should never */
+ /* generate an interrupt however. */
+ m8xx.tbscr |= M8xx_TBSCR_TBIRQ(4) | M8xx_TBSCR_TBE;
+
+ Timer_starting = get_itimer();
+}
+
+int Read_timer(void)
+{
+ rtems_unsigned32 clicks;
+ rtems_unsigned32 total;
+
+ clicks = get_itimer();
+
+ total = clicks - Timer_starting;
+
+ if ( Timer_driver_Find_average_overhead == 1 )
+ return total; /* in XXX microsecond units */
+
+ else {
+ if ( total < Cpu_table.timer_least_valid ) {
+ return 0; /* below timer resolution */
+ }
+ return (total - Cpu_table.timer_average_overhead);
+ }
+}
+
+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;
+}