diff options
Diffstat (limited to 'bsps/powerpc/shared/btimer/btimer-ppc-dec.c')
-rw-r--r-- | bsps/powerpc/shared/btimer/btimer-ppc-dec.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/bsps/powerpc/shared/btimer/btimer-ppc-dec.c b/bsps/powerpc/shared/btimer/btimer-ppc-dec.c new file mode 100644 index 0000000000..d161710732 --- /dev/null +++ b/bsps/powerpc/shared/btimer/btimer-ppc-dec.c @@ -0,0 +1,88 @@ +/** + * @file + * @brief + * + * This file implements a benchmark timer using the PPC Timebase Register. + */ + +/* + * COPYRIGHT (c) 1989-2014. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may in + * the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#include <bsp.h> +#include <rtems.h> +#include <rtems/system.h> +#include <rtems/btimer.h> +#include <assert.h> +#include <libcpu/powerpc-utility.h> + +#ifndef BSP_Convert_decrementer +#define BSP_Convert_decrementer(value) (value) +#endif + +uint64_t Timer_driver_Start_time; + +bool benchmark_timer_find_average_overhead = false; +unsigned clicks_overhead = 0; + +/* + * Timer Get overhead + */ +static int Timer_get_clicks_overhead(void) +{ + uint64_t clicks; + + PPC_Set_timebase_register((uint64_t) 0); + clicks = PPC_Get_timebase_register(); + assert(clicks <= 0xffffffff); + clicks_overhead = (unsigned) clicks; + return clicks_overhead; +} + +/* + * benchmark_timer_initialize + */ +void benchmark_timer_initialize(void) +{ + + /* + * Timer runs long and accurate enough not to require an interrupt. + */ + + if (clicks_overhead == 0) clicks_overhead = Timer_get_clicks_overhead(); + PPC_Set_timebase_register((uint64_t) 0); +} + + +/* + * benchmark_timer_read + */ + +benchmark_timer_t benchmark_timer_read(void) +{ + uint64_t total64; + uint32_t total; + + /* approximately CLOCK_SPEED clicks per microsecond */ + + total64 = PPC_Get_timebase_register(); + + assert( total64 <= 0xffffffff ); /* fits into a uint32_t */ + + total = (uint32_t) total64; + + if ( benchmark_timer_find_average_overhead == true ) + return total; /* in "clicks" of the decrementer units */ + + return (int) BSP_Convert_decrementer(total - clicks_overhead); +} + +void benchmark_timer_disable_subtracting_average_overhead(bool find_flag) +{ + benchmark_timer_find_average_overhead = find_flag; +} |