zephyr/drivers/timer/xtensa_sys_timer.c
Piotr Zięcik 0c0c0d93ea drivers: timer: Do not use CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC
On some SoCs the frequency of the system clock is obtained at run time
as the exact configuration of the hardware is not known at compile time.
On such platforms using CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC define
directly introduces timing errors.

This commit replaces CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC by the call
to inline function sys_clock_hw_cycles_per_sec() which always returns
correct frequency of the system clock.

Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>
2019-07-24 15:10:02 +02:00

129 lines
2.7 KiB
C

/*
* Copyright (c) 2018 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <drivers/timer/system_timer.h>
#include <sys_clock.h>
#include <spinlock.h>
#include <xtensa_rtos.h>
#define TIMER_IRQ UTIL_CAT(XCHAL_TIMER, \
UTIL_CAT(CONFIG_XTENSA_TIMER_ID, _INTERRUPT))
#define CYC_PER_TICK (sys_clock_hw_cycles_per_sec() \
/ CONFIG_SYS_CLOCK_TICKS_PER_SEC)
#define MAX_TICKS ((0xffffffffu - CYC_PER_TICK) / CYC_PER_TICK)
#define MIN_DELAY 1000
static struct k_spinlock lock;
static unsigned int last_count;
static void set_ccompare(u32_t val)
{
__asm__ volatile ("wsr.CCOMPARE" STRINGIFY(CONFIG_XTENSA_TIMER_ID) " %0"
:: "r"(val));
}
static u32_t ccount(void)
{
u32_t val;
__asm__ volatile ("rsr.CCOUNT %0" : "=r"(val));
return val;
}
static void ccompare_isr(void *arg)
{
ARG_UNUSED(arg);
k_spinlock_key_t key = k_spin_lock(&lock);
u32_t curr = ccount();
u32_t dticks = (curr - last_count) / CYC_PER_TICK;
last_count += dticks * CYC_PER_TICK;
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL) ||
IS_ENABLED(CONFIG_QEMU_TICKLESS_WORKAROUND)) {
u32_t next = last_count + CYC_PER_TICK;
if ((s32_t)(next - curr) < MIN_DELAY) {
next += CYC_PER_TICK;
}
set_ccompare(next);
}
k_spin_unlock(&lock, key);
z_clock_announce(IS_ENABLED(CONFIG_TICKLESS_KERNEL) ? dticks : 1);
}
/* The legacy Xtensa platform code handles the timer interrupt via a
* special path and must find it via this name. Remove once ASM2 is
* pervasive.
*/
#ifndef CONFIG_XTENSA_ASM2
void timer_int_handler(void *arg)
{
return ccompare_isr(arg);
}
#endif
int z_clock_driver_init(struct device *device)
{
IRQ_CONNECT(TIMER_IRQ, 0, ccompare_isr, 0, 0);
set_ccompare(ccount() + CYC_PER_TICK);
irq_enable(TIMER_IRQ);
return 0;
}
void z_clock_set_timeout(s32_t ticks, bool idle)
{
ARG_UNUSED(idle);
#if defined(CONFIG_TICKLESS_KERNEL) && !defined(CONFIG_QEMU_TICKLESS_WORKAROUND)
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 curr = ccount(), cyc;
/* Round up to next tick boundary */
cyc = ticks * CYC_PER_TICK + (curr - last_count) + (CYC_PER_TICK - 1);
cyc = (cyc / CYC_PER_TICK) * CYC_PER_TICK;
cyc += last_count;
if ((cyc - curr) < MIN_DELAY) {
cyc += CYC_PER_TICK;
}
set_ccompare(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 = (ccount() - last_count) / CYC_PER_TICK;
k_spin_unlock(&lock, key);
return ret;
}
u32_t z_timer_cycle_get_32(void)
{
return ccount();
}
#ifdef CONFIG_SMP
void smp_timer_init(void)
{
set_ccompare(ccount() + CYC_PER_TICK);
irq_enable(TIMER_IRQ);
}
#endif