1 /*
2  * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
3  *
4  * SPDX-License-Identifier: Apache-2.0
5  */
6 #include "esp_timer_impl.h"
7 #include "esp_timer.h"
8 #include "esp_err.h"
9 #include "esp_task.h"
10 #include "esp_attr.h"
11 #include <zephyr/kernel.h>
12 
13 /* Spinlock used to protect access to the hardware registers. */
14 unsigned int s_time_update_lock;
15 
16 /* Alarm values to generate interrupt on match
17  * [0] - for ESP_TIMER_TASK alarms,
18  * [1] - for ESP_TIMER_ISR alarms.
19 */
20 uint64_t timestamp_id[2] = { UINT64_MAX, UINT64_MAX };
21 
esp_timer_impl_lock(void)22 void esp_timer_impl_lock(void)
23 {
24     s_time_update_lock = irq_lock();
25 }
26 
esp_timer_impl_unlock(void)27 void esp_timer_impl_unlock(void)
28 {
29     irq_unlock(s_time_update_lock);
30 }
31 
32 void esp_timer_private_lock(void) __attribute__((alias("esp_timer_impl_lock")));
33 void esp_timer_private_unlock(void) __attribute__((alias("esp_timer_impl_unlock")));
34 
esp_timer_impl_set_alarm(uint64_t timestamp)35 void IRAM_ATTR esp_timer_impl_set_alarm(uint64_t timestamp)
36 {
37     esp_timer_impl_set_alarm_id(timestamp, 0);
38 }
39 
40 #ifdef CONFIG_ESP_TIMER_SUPPORTS_ISR_DISPATCH_METHOD
esp_timer_impl_try_to_set_next_alarm(void)41 void IRAM_ATTR esp_timer_impl_try_to_set_next_alarm(void) {
42     s_time_update_lock = irq_lock();
43     unsigned now_alarm_idx;  // ISR is called due to this current alarm
44     unsigned next_alarm_idx; // The following alarm after now_alarm_idx
45     if (timestamp_id[0] < timestamp_id[1]) {
46         now_alarm_idx = 0;
47         next_alarm_idx = 1;
48     } else {
49         now_alarm_idx = 1;
50         next_alarm_idx = 0;
51     }
52 
53     if (timestamp_id[next_alarm_idx] != UINT64_MAX) {
54         // The following alarm is valid and can be used.
55         // Remove the current alarm from consideration.
56         esp_timer_impl_set_alarm_id(UINT64_MAX, now_alarm_idx);
57     } else {
58         // There is no the following alarm.
59         // Remove the current alarm from consideration as well.
60         timestamp_id[now_alarm_idx] = UINT64_MAX;
61     }
62     irq_unlock(s_time_update_lock);
63 }
64 #endif
65 
66 /* FIXME: This value is safe for 80MHz APB frequency, should be modified to depend on clock frequency. */
esp_timer_impl_get_min_period_us(void)67 uint64_t IRAM_ATTR esp_timer_impl_get_min_period_us(void)
68 {
69     return 50;
70 }
71