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/*
* Copyright (c) 2017 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/kernel.h>
#include <zephyr/arch/cpu.h>
#include <zephyr/device.h>
#include <zephyr/drivers/timer/system_timer.h>
#include <altera_common.h>
#include "altera_avalon_timer_regs.h"
#include "altera_avalon_timer.h"
/* The old driver "now" API would return a full uptime value. The new
* one only requires the driver to track ticks since the last announce
* call. Implement the new call in terms of the old one on legacy
* drivers by keeping (yet another) uptime value locally.
*/
static uint32_t driver_uptime;
static uint32_t accumulated_cycle_count;
static int32_t _sys_idle_elapsed_ticks = 1;
static void wrapped_announce(int32_t ticks)
{
driver_uptime += ticks;
sys_clock_announce(ticks);
}
static void timer_irq_handler(const void *unused)
{
ARG_UNUSED(unused);
accumulated_cycle_count += k_ticks_to_cyc_floor32(1);
/* Clear the interrupt */
alt_handle_irq((void *)TIMER_0_BASE, TIMER_0_IRQ);
wrapped_announce(_sys_idle_elapsed_ticks);
}
uint32_t sys_clock_cycle_get_32(void)
{
/* Per the Altera Embedded IP Peripherals guide, you cannot
* use a timer instance for both the system clock and timestamps
* at the same time.
*
* Having this function return accumulated_cycle_count + get_snapshot()
* does not work reliably. It's possible for the current countdown
* to reset to the next interval before the timer interrupt is
* delivered (and accumulated cycle count gets updated). The result
* is an unlucky call to this function will appear to jump backward
* in time.
*
* To properly obtain timestamps, the CPU must be configured with
* a second timer peripheral instance that is configured to
* count down from some large initial 64-bit value. This
* is currently unimplemented.
*/
return accumulated_cycle_count;
}
uint32_t sys_clock_elapsed(void)
{
return 0;
}
static int sys_clock_driver_init(const struct device *dev)
{
ARG_UNUSED(dev);
IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_0_BASE,
k_ticks_to_cyc_floor32(1) & 0xFFFF);
IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_0_BASE,
(k_ticks_to_cyc_floor32(1) >> 16) & 0xFFFF);
IRQ_CONNECT(TIMER_0_IRQ, 0, timer_irq_handler, NULL, 0);
irq_enable(TIMER_0_IRQ);
alt_avalon_timer_sc_init((void *)TIMER_0_BASE, 0,
TIMER_0_IRQ, k_ticks_to_cyc_floor32(1));
return 0;
}
SYS_INIT(sys_clock_driver_init, PRE_KERNEL_2,
CONFIG_SYSTEM_CLOCK_INIT_PRIORITY);
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