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/*
* 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 <leon.h>
#include <rtems/counter.h>
static volatile struct gptimer_regs *adev_to_gpt(struct ambapp_dev *adev)
{
return (volatile struct gptimer_regs *) DEV_TO_APB(adev)->start;
}
static CPU_Counter_ticks free_counter_difference(
CPU_Counter_ticks second,
CPU_Counter_ticks first
)
{
return first - second;
}
static CPU_Counter_ticks clock_counter_difference(
CPU_Counter_ticks second,
CPU_Counter_ticks first
)
{
CPU_Counter_ticks period = rtems_configuration_get_microseconds_per_tick();
return (first + period - second) % period;
}
static void gpt_counter_initialize(
volatile struct gptimer_regs *gpt,
size_t timer_index,
uint32_t frequency,
SPARC_Counter_difference counter_difference
)
{
_SPARC_Counter_initialize(
(volatile const uint32_t *) &gpt->timer[timer_index].value,
counter_difference
);
rtems_counter_initialize_converter(frequency);
}
void leon3_cpu_counter_initialize(void)
{
struct ambapp_dev *adev;
int idx = 1;
adev = (void *) ambapp_for_each(
&ambapp_plb,
OPTIONS_ALL | OPTIONS_APB_SLVS,
VENDOR_GAISLER,
GAISLER_GPTIMER,
ambapp_find_by_idx,
&idx
);
if (adev != NULL) {
/* Use the second GPTIMER if available */
volatile struct gptimer_regs *gpt = adev_to_gpt(adev);
uint32_t max_frequency = ambapp_freq_get(&ambapp_plb, adev);
unsigned min_prescaler = 8;
uint32_t frequency = max_frequency / min_prescaler;
gpt->scaler_reload = min_prescaler - 1;
gpt->timer[0].reload = 0xffffffff;
gpt->timer[0].ctrl = LEON3_GPTIMER_EN | LEON3_GPTIMER_RL
| LEON3_GPTIMER_LD;
gpt_counter_initialize(gpt, 0, frequency, free_counter_difference);
} else if (LEON3_Timer_Regs != NULL) {
/* Fall back to the first GPTIMER if available */
gpt_counter_initialize(
LEON3_Timer_Regs,
LEON3_CLOCK_INDEX,
LEON3_GPTIMER_0_FREQUENCY_SET_BY_BOOT_LOADER,
clock_counter_difference
);
}
}
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