zephyr/drivers/timer/nrf_rtc_timer.c

158 lines
3.6 KiB
C

/*
* Copyright (c) 2016-2017 Nordic Semiconductor ASA
* Copyright (c) 2018 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <soc.h>
#include <clock_control.h>
#include <drivers/clock_control/nrf_clock_control.h>
#include <system_timer.h>
#include <sys_clock.h>
#include <nrf_rtc.h>
#include <spinlock.h>
#define RTC NRF_RTC1
#define COUNTER_MAX 0x00ffffff
#define CYC_PER_TICK (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC \
/ CONFIG_SYS_CLOCK_TICKS_PER_SEC)
#define MAX_TICKS ((COUNTER_MAX - CYC_PER_TICK) / CYC_PER_TICK)
#define MIN_DELAY 32
static struct k_spinlock lock;
static u32_t last_count;
static u32_t counter_sub(u32_t a, u32_t b)
{
return (a - b) & COUNTER_MAX;
}
static void set_comparator(u32_t cyc)
{
nrf_rtc_cc_set(RTC, 0, cyc & COUNTER_MAX);
}
static u32_t counter(void)
{
return nrf_rtc_counter_get(RTC);
}
/* Note: this function has public linkage, and MUST have this
* particular name. The platform architecture itself doesn't care,
* but there is a test (tests/kernel/arm_irq_vector_table) that needs
* to find it to it can set it in a custom vector table. Should
* probably better abstract that at some point (e.g. query and reset
* it by pointer at runtime, maybe?) so we don't have this leaky
* symbol.
*/
void rtc1_nrf_isr(void *arg)
{
ARG_UNUSED(arg);
RTC->EVENTS_COMPARE[0] = 0;
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t t = counter();
u32_t dticks = counter_sub(t, last_count) / CYC_PER_TICK;
last_count += dticks * CYC_PER_TICK;
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
u32_t next = last_count + CYC_PER_TICK;
if (counter_sub(next, t) < MIN_DELAY) {
next += CYC_PER_TICK;
}
set_comparator(next);
}
k_spin_unlock(&lock, key);
z_clock_announce(IS_ENABLED(CONFIG_TICKLESS_KERNEL) ? dticks : 1);
}
int z_clock_driver_init(struct device *device)
{
struct device *clock;
ARG_UNUSED(device);
clock = device_get_binding(DT_NORDIC_NRF_CLOCK_0_LABEL "_32K");
if (!clock) {
return -1;
}
clock_control_on(clock, (void *)CLOCK_CONTROL_NRF_K32SRC);
/* TODO: replace with counter driver to access RTC */
nrf_rtc_prescaler_set(RTC, 0);
nrf_rtc_cc_set(RTC, 0, CYC_PER_TICK);
nrf_rtc_int_enable(RTC, RTC_INTENSET_COMPARE0_Msk);
/* Clear the event flag and possible pending interrupt */
nrf_rtc_event_clear(RTC, NRF_RTC_EVENT_COMPARE_0);
NVIC_ClearPendingIRQ(RTC1_IRQn);
IRQ_CONNECT(RTC1_IRQn, 1, rtc1_nrf_isr, 0, 0);
irq_enable(RTC1_IRQn);
nrf_rtc_task_trigger(RTC, NRF_RTC_TASK_CLEAR);
nrf_rtc_task_trigger(RTC, NRF_RTC_TASK_START);
if (!IS_ENABLED(TICKLESS_KERNEL)) {
set_comparator(counter() + CYC_PER_TICK);
}
return 0;
}
void z_clock_set_timeout(s32_t ticks, bool idle)
{
ARG_UNUSED(idle);
#ifdef CONFIG_TICKLESS_KERNEL
ticks = (ticks == K_FOREVER) ? MAX_TICKS : ticks;
ticks = MAX(MIN(ticks - 1, (s32_t)MAX_TICKS), 0);
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t cyc, t = counter();
/* Round up to next tick boundary */
cyc = ticks * CYC_PER_TICK + counter_sub(t, last_count);
cyc += (CYC_PER_TICK - 1);
cyc = (cyc / CYC_PER_TICK) * CYC_PER_TICK;
cyc += last_count;
if (counter_sub(cyc, t) < MIN_DELAY) {
cyc += CYC_PER_TICK;
}
set_comparator(cyc);
k_spin_unlock(&lock, key);
#endif
}
u32_t z_clock_elapsed(void)
{
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t ret = counter_sub(counter(), last_count) / CYC_PER_TICK;
k_spin_unlock(&lock, key);
return ret;
}
u32_t z_timer_cycle_get_32(void)
{
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t ret = counter_sub(counter(), last_count) + last_count;
k_spin_unlock(&lock, key);
return ret;
}