Files
lk/platform/nrf51xxx/timer.c
Travis Geiselbrecht f7d8e2300c [warnings] add -Wshadow which helps detect local variables that override globals
Nothing particularly bad showed up but cleaned up a bit of code.
2020-07-25 16:49:25 -07:00

85 lines
1.9 KiB
C

/*
* Copyright (c) 2015 Eric Holland
*
* Use of this source code is governed by a MIT-style
* license that can be found in the LICENSE file or at
* https://opensource.org/licenses/MIT
*/
#include <lk/err.h>
#include <lk/debug.h>
#include <lk/trace.h>
#include <arch/arm/cm.h>
#include <platform.h>
#include <platform/nrf51.h>
#include <platform/system_nrf51.h>
#include <platform/timer.h>
#include <sys/types.h>
static volatile uint64_t current_ticks;
static uint32_t tick_rate = 0;
static uint32_t tick_rate_mhz = 0;
static lk_time_t tick_interval_ms;
static platform_timer_callback cb;
static void *cb_args;
typedef enum handler_return (*platform_timer_callback)(void *arg, lk_time_t now);
status_t platform_set_periodic_timer(platform_timer_callback callback, void *arg, lk_time_t interval) {
cb = callback;
cb_args = arg;
tick_interval_ms = interval;
uint32_t ticks = tick_rate / ( 1000 / interval );
NRF_CLOCK->LFCLKSRC = CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos;
NRF_CLOCK->TASKS_LFCLKSTART = 1;
NRF_RTC1->PRESCALER = ticks;
NRF_RTC1->INTENSET = RTC_INTENSET_TICK_Enabled << RTC_INTENSET_TICK_Pos;
NRF_RTC1->EVENTS_TICK = 0;
NRF_RTC1->TASKS_START = 1;
NVIC_EnableIRQ(RTC1_IRQn);
return NO_ERROR;
}
lk_time_t current_time(void) {
uint64_t t;
do {
t = current_ticks;
} while (current_ticks != t);
return t * tick_interval_ms;
}
lk_bigtime_t current_time_hires(void) {
return current_time() * 1000;
}
void nrf51_RTC1_IRQ(void) {
current_ticks++;
arm_cm_irq_entry();
NRF_RTC1->EVENTS_TICK = 0;
bool resched = false;
if (cb) {
lk_time_t now = current_time();
if (cb(cb_args, now) == INT_RESCHEDULE)
resched = true;
}
arm_cm_irq_exit(resched);
}
void arm_cm_systick_init(uint32_t mhz) {
tick_rate = mhz;
tick_rate_mhz = mhz / 1000000;
}