diff options
Diffstat (limited to 'c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c')
| -rw-r--r-- | c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c | 128 |
1 files changed, 88 insertions, 40 deletions
diff --git a/c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c b/c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c index 3139e62d6d..5a1ce5e2a6 100644 --- a/c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c +++ b/c/src/lib/libcpu/powerpc/mpc5xx/timer/timer.c @@ -1,70 +1,118 @@ /* 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. + * This file manages the interval timer on the PowerPC MPC5xx. + * 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. * - * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * + * MPC5xx port sponsored by Defence Research and Development Canada - Suffield + * Copyright (C) 2004, Real-Time Systems Inc. (querbach@realtime.bc.ca) + * + * Derived from c/src/lib/libcpu/powerpc/mpc8xx/timer/timer.c: + * + * 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). - * 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. + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. * - * timer.c,v 1.2 1995/05/31 16:56:39 joel Exp + * $Id$ */ #include <rtems.h> +#include <mpc5xx.h> + +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; -rtems_boolean Timer_driver_Find_average_overhead; + asm volatile ("mftb %0" : "=r" ((ret))); /* TBLO */ -static unsigned int volatile lastInitValue; + return ret; +} -void Timer_initialize( void ) +void Timer_initialize(void) { - asm volatile( " mftb %0": "=r" (lastInitValue) ); + /* set interrupt level and enable timebase. This should never */ + /* generate an interrupt however. */ + usiu.tbscrk = USIU_UNLOCK_KEY; + usiu.tbscr |= USIU_TBSCR_TBIRQ(4) /* interrupt priority level */ + | USIU_TBSCR_TBF /* freeze timebase during debug */ + | USIU_TBSCR_TBE; /* enable timebase */ + usiu.tbscrk = 0; + + Timer_starting = get_itimer(); } -/* - * 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. - */ +#ifndef rtems_cpu_configuration_get_timer_least_valid +#define rtems_cpu_configuration_get_timer_least_valid() 0 +#endif -#define AVG_OVERHEAD 0 /* It typically takes X.X microseconds */ - /* (Y countdowns) to start/stop the timer. */ - /* This value is in microseconds. */ -#define LEAST_VALID 1 /* Don't trust a clicks value lower than this */ +#ifndef rtems_cpu_configuration_get_timer_average_overhead +#define rtems_cpu_configuration_get_timer_average_overhead() 0 +#endif -int Read_timer( void ) +int Read_timer(void) { - uint32_t value; - asm volatile ( " mftb %0": "=r" (value) ); - return value - lastInitValue; -} + rtems_unsigned32 clicks; + rtems_unsigned32 total; -/* - * Empty function call used in loops to measure basic cost of looping - * in Timing Test Suite. - */ + clicks = get_itimer(); + + total = clicks - Timer_starting; + + if ( Timer_driver_Find_average_overhead == 1 ) + return total; /* in XXX microsecond units */ + + else { + if ( total < rtems_cpu_configuration_get_timer_least_valid() ) { + return 0; /* below timer resolution */ + } + return (total - rtems_cpu_configuration_get_timer_average_overhead()); + } +} -rtems_status_code Empty_function( void ) +rtems_status_code Empty_function(void) { return RTEMS_SUCCESSFUL; } -void Set_find_average_overhead( - rtems_boolean find_flag -) +void Set_find_average_overhead(rtems_boolean find_flag) { Timer_driver_Find_average_overhead = find_flag; } |