forked from Imagelibrary/rtems
bb22a3f3af
Use only one timer driver variant based on the standard PowerPC time base. This patch is a part of the BSP source reorganization. Update #3285.
89 lines
1.9 KiB
C
89 lines
1.9 KiB
C
/**
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* @file
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* @brief
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*
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* This file implements a benchmark timer using the PPC Timebase Register.
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*/
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/*
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* COPYRIGHT (c) 1989-2014.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may in
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* the file LICENSE in this distribution or at
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* http://www.rtems.org/license/LICENSE.
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*/
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#include <bsp.h>
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#include <rtems.h>
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#include <rtems/system.h>
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#include <rtems/btimer.h>
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#include <assert.h>
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#include <libcpu/powerpc-utility.h>
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#ifndef BSP_Convert_decrementer
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#define BSP_Convert_decrementer(value) (value)
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#endif
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uint64_t Timer_driver_Start_time;
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bool benchmark_timer_find_average_overhead = false;
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unsigned clicks_overhead = 0;
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/*
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* Timer Get overhead
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*/
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static int Timer_get_clicks_overhead(void)
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{
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uint64_t clicks;
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PPC_Set_timebase_register((uint64_t) 0);
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clicks = PPC_Get_timebase_register();
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assert(clicks <= 0xffffffff);
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clicks_overhead = (unsigned) clicks;
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return clicks_overhead;
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}
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/*
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* benchmark_timer_initialize
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*/
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void benchmark_timer_initialize(void)
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{
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/*
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* Timer runs long and accurate enough not to require an interrupt.
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*/
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if (clicks_overhead == 0) clicks_overhead = Timer_get_clicks_overhead();
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PPC_Set_timebase_register((uint64_t) 0);
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}
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/*
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* benchmark_timer_read
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*/
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benchmark_timer_t benchmark_timer_read(void)
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{
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uint64_t total64;
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uint32_t total;
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/* approximately CLOCK_SPEED clicks per microsecond */
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total64 = PPC_Get_timebase_register();
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assert( total64 <= 0xffffffff ); /* fits into a uint32_t */
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total = (uint32_t) total64;
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if ( benchmark_timer_find_average_overhead == true )
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return total; /* in "clicks" of the decrementer units */
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return (int) BSP_Convert_decrementer(total - clicks_overhead);
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}
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void benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
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{
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benchmark_timer_find_average_overhead = find_flag;
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}
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