driver: timer: esp32c3: added tickless support
For esp32c3 system timer clock driver enabling tickless mode
kernel
Signed-off-by: Felipe Neves <felipe.neves@espressif.com>
diff --git a/drivers/timer/esp32c3_sys_timer.c b/drivers/timer/esp32c3_sys_timer.c
index 478e313..65755af 100644
--- a/drivers/timer/esp32c3_sys_timer.c
+++ b/drivers/timer/esp32c3_sys_timer.c
@@ -17,13 +17,55 @@
#include <sys_clock.h>
#include <soc.h>
-#define SYS_TIMER_CPU_IRQ 1
+#define SYS_TIMER_CPU_IRQ 16
+
+#define CYC_PER_TICK ((uint32_t)((uint64_t)sys_clock_hw_cycles_per_sec() \
+ / (uint64_t)CONFIG_SYS_CLOCK_TICKS_PER_SEC))
+#define MAX_CYC 0xffffffffu
+#define MAX_TICKS ((MAX_CYC - CYC_PER_TICK) / CYC_PER_TICK)
+#define MIN_DELAY 1000
+
+#define TICKLESS IS_ENABLED(CONFIG_TICKLESS_KERNEL)
+
+static struct k_spinlock lock;
+static uint64_t last_count;
+
+static void set_systimer_alarm(uint64_t time)
+{
+ systimer_hal_select_alarm_mode(SYSTIMER_ALARM_0, SYSTIMER_ALARM_MODE_ONESHOT);
+ systimer_hal_set_alarm_target(SYSTIMER_ALARM_0, time);
+ systimer_hal_enable_alarm_int(SYSTIMER_ALARM_0);
+}
+
+static uint64_t systimer_alarm(void)
+{
+ return systimer_hal_get_time(SYSTIMER_COUNTER_1);
+}
static void sys_timer_isr(const void *arg)
{
ARG_UNUSED(arg);
+
systimer_ll_clear_alarm_int(SYSTIMER_ALARM_0);
- sys_clock_announce(1);
+
+ k_spinlock_key_t key = k_spin_lock(&lock);
+ uint64_t now = systimer_alarm();
+
+ uint32_t dticks = (uint32_t)((now - last_count) / CYC_PER_TICK);
+
+ last_count += dticks * CYC_PER_TICK;
+
+ if (!TICKLESS) {
+ uint64_t next = last_count + CYC_PER_TICK;
+
+ if ((int64_t)(next - now) < MIN_DELAY) {
+ next += CYC_PER_TICK;
+ }
+ set_systimer_alarm(next);
+ }
+
+ k_spin_unlock(&lock, key);
+ sys_clock_announce(IS_ENABLED(CONFIG_TICKLESS_KERNEL) ? dticks : 1);
}
int sys_clock_driver_init(const struct device *dev)
@@ -34,16 +76,13 @@
ETS_SYSTIMER_TARGET0_EDGE_INTR_SOURCE,
SYS_TIMER_CPU_IRQ);
IRQ_CONNECT(SYS_TIMER_CPU_IRQ, 0, sys_timer_isr, NULL, 0);
- irq_enable(SYS_TIMER_CPU_IRQ);
-
systimer_hal_init();
systimer_hal_connect_alarm_counter(SYSTIMER_ALARM_0, SYSTIMER_COUNTER_1);
systimer_hal_enable_counter(SYSTIMER_COUNTER_1);
systimer_hal_counter_can_stall_by_cpu(SYSTIMER_COUNTER_1, 0, true);
- systimer_hal_set_alarm_period(SYSTIMER_ALARM_0,
- CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC / CONFIG_SYS_CLOCK_TICKS_PER_SEC);
- systimer_hal_select_alarm_mode(SYSTIMER_ALARM_0, SYSTIMER_ALARM_MODE_PERIOD);
- systimer_hal_enable_alarm_int(SYSTIMER_ALARM_0);
+ last_count = systimer_alarm();
+ set_systimer_alarm(last_count + CYC_PER_TICK);
+ irq_enable(SYS_TIMER_CPU_IRQ);
return 0;
}
@@ -51,13 +90,44 @@
void sys_clock_set_timeout(int32_t ticks, bool idle)
{
ARG_UNUSED(idle);
- ARG_UNUSED(ticks);
+
+#if defined(CONFIG_TICKLESS_KERNEL)
+ ticks = ticks == K_TICKS_FOREVER ? MAX_TICKS : ticks;
+ ticks = CLAMP(ticks - 1, 0, (int32_t)MAX_TICKS);
+
+ k_spinlock_key_t key = k_spin_lock(&lock);
+ uint64_t now = systimer_alarm();
+ uint32_t adj, cyc = ticks * CYC_PER_TICK;
+
+ /* Round up to next tick boundary. */
+ adj = (uint32_t)(now - last_count) + (CYC_PER_TICK - 1);
+ if (cyc <= MAX_CYC - adj) {
+ cyc += adj;
+ } else {
+ cyc = MAX_CYC;
+ }
+ cyc = (cyc / CYC_PER_TICK) * CYC_PER_TICK;
+
+ if ((int32_t)(cyc + last_count - now) < MIN_DELAY) {
+ cyc += CYC_PER_TICK;
+ }
+
+ set_systimer_alarm(cyc + last_count);
+ k_spin_unlock(&lock, key);
+#endif
}
uint32_t sys_clock_elapsed(void)
{
- /* Tickless is not supported yet */
- return 0;
+ if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
+ return 0;
+ }
+
+ k_spinlock_key_t key = k_spin_lock(&lock);
+ uint32_t ret = ((uint32_t)systimer_alarm() - (uint32_t)last_count) / CYC_PER_TICK;
+
+ k_spin_unlock(&lock, key);
+ return ret;
}
uint32_t sys_clock_cycle_get_32(void)
