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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-02-12 10:31:38 +0100 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2014-02-14 10:28:29 +0100 |
commit | 24bf11eca11947d961cc9bb5f7d92dabff169e93 (patch) | |
tree | b28f3aa8a21df91e8feaf324613aa76460559837 /c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c | |
parent | bsps/arm: Fix Cortex-A9 MPCore nanoseconds handler (diff) | |
download | rtems-24bf11eca11947d961cc9bb5f7d92dabff169e93.tar.bz2 |
score: Add CPU counter support
Add a CPU counter interface to allow access to a free-running counter.
It is useful to measure short time intervals. This can be used for
example to enable profiling of critical low-level functions.
Add two busy wait functions rtems_counter_delay_ticks() and
rtems_counter_delay_nanoseconds() implemented via the CPU counter.
Diffstat (limited to 'c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c')
-rw-r--r-- | c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c b/c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c new file mode 100644 index 0000000000..2863f359e7 --- /dev/null +++ b/c/src/lib/libbsp/sparc/leon3/startup/cpucounter.c @@ -0,0 +1,63 @@ +/* + * Copyright (c) 2014 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Dornierstr. 4 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * 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. + */ + +#include <bsp.h> +#include <leon.h> + +#include <rtems/counter.h> + +static volatile struct gptimer_regs *leon3_cpu_counter_gpt; + +void leon3_cpu_counter_initialize(void) +{ + struct ambapp_dev *adev; + int idx = 1; + volatile struct gptimer_regs *gpt; + unsigned new_prescaler = 8; + unsigned prescaler; + uint32_t frequency; + + adev = (void *) ambapp_for_each( + &ambapp_plb, + OPTIONS_ALL | OPTIONS_APB_SLVS, + VENDOR_GAISLER, + GAISLER_GPTIMER, + ambapp_find_by_idx, + &idx + ); + if (adev == NULL) { + rtems_fatal(RTEMS_FATAL_SOURCE_BSP_SPECIFIC, LEON3_FATAL_CPU_COUNTER_INIT); + } + + gpt = (volatile struct gptimer_regs *) DEV_TO_APB(adev)->start; + + prescaler = gpt->scaler_reload + 1; + gpt->scaler_reload = new_prescaler - 1; + gpt->timer[0].reload = 0xffffffff; + gpt->timer[0].ctrl = LEON3_GPTIMER_EN | LEON3_GPTIMER_RL + | LEON3_GPTIMER_LD; + + leon3_cpu_counter_gpt = gpt; + + /* Assume that GRMON initialized the timer to 1MHz */ + frequency = UINT32_C(1000000) * (prescaler / new_prescaler); + rtems_counter_initialize_converter(frequency); +} + +CPU_Counter_ticks _CPU_Counter_read(void) +{ + volatile struct gptimer_regs *gpt = leon3_cpu_counter_gpt; + + return 0U - gpt->timer[0].value; +} |