zephyr/drivers/timer/pulpino_timer.c

75 lines
1.6 KiB
C

/*
* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <arch/cpu.h>
#include <device.h>
#include <system_timer.h>
#include <board.h>
/* Timer Ctrl Bitfields */
#define TIMER_CTRL_EN (1 << 0) /* Timer Enable Bit */
#define TIMER_CTRL_PRE(x) (((x) & 0x07) << 3) /* Prescaler Value */
typedef struct {
uint32_t val;
uint32_t ctrl;
uint32_t cmp;
} pulpino_timer_t;
static volatile pulpino_timer_t *timer = (pulpino_timer_t *)PULP_TIMER_A_BASE;
static uint32_t accumulated_cycle_count;
static void pulpino_timer_irq_handler(void *unused)
{
ARG_UNUSED(unused);
/* Reset counter */
timer->val = 0;
accumulated_cycle_count += sys_clock_hw_cycles_per_tick;
_sys_clock_tick_announce();
}
#ifdef CONFIG_TICKLESS_IDLE
#error "Tickless idle not yet implemented for pulpino timer"
#endif
int _sys_clock_driver_init(struct device *device)
{
ARG_UNUSED(device);
IRQ_CONNECT(PULP_TIMER_A_CMP_IRQ, 0,
pulpino_timer_irq_handler, NULL, 0);
irq_enable(PULP_TIMER_A_CMP_IRQ);
/*
* Initialize timer.
* Reset counter and set timer to generate interrupt
* every sys_clock_hw_cycles_per_tick
*/
timer->val = 0;
timer->cmp = sys_clock_hw_cycles_per_tick;
timer->ctrl = TIMER_CTRL_EN;
return 0;
}
/**
*
* @brief Read the platform's timer hardware
*
* This routine returns the current time in terms of timer hardware clock
* cycles.
*
* @return up counter of elapsed clock cycles
*/
uint32_t _timer_cycle_get_32(void)
{
return accumulated_cycle_count + timer->val;
}