1 /*
2 * Copyright (c) 2018 Intel Corporation.
3 * Copyright (c) 2022 Nordic Semiconductor ASA
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #include <stdint.h>
9
10 #include <zephyr/pm/policy.h>
11 #include <zephyr/spinlock.h>
12 #include <zephyr/sys/time_units.h>
13
14 /** Lock to synchronize access to the latency request list. */
15 static struct k_spinlock latency_lock;
16 /** List of maximum latency requests. */
17 static sys_slist_t latency_reqs;
18 /** Maximum CPU latency in us */
19 static int32_t max_latency_us = SYS_FOREVER_US;
20 /** Maximum CPU latency in cycles */
21 int32_t max_latency_cyc = -1;
22 /** List of latency change subscribers. */
23 static sys_slist_t latency_subs;
24
25 /** @brief Update maximum allowed latency. */
update_max_latency(void)26 static void update_max_latency(void)
27 {
28 int32_t new_max_latency_us = SYS_FOREVER_US;
29 struct pm_policy_latency_request *req;
30
31 SYS_SLIST_FOR_EACH_CONTAINER(&latency_reqs, req, node) {
32 if ((new_max_latency_us == SYS_FOREVER_US) ||
33 ((int32_t)req->value_us < new_max_latency_us)) {
34 new_max_latency_us = (int32_t)req->value_us;
35 }
36 }
37
38 if (max_latency_us != new_max_latency_us) {
39 struct pm_policy_latency_subscription *sreq;
40 int32_t new_max_latency_cyc = -1;
41
42 SYS_SLIST_FOR_EACH_CONTAINER(&latency_subs, sreq, node) {
43 sreq->cb(new_max_latency_us);
44 }
45
46 if (new_max_latency_us != SYS_FOREVER_US) {
47 new_max_latency_cyc = (int32_t)k_us_to_cyc_ceil32(new_max_latency_us);
48 }
49
50 max_latency_us = new_max_latency_us;
51 max_latency_cyc = new_max_latency_cyc;
52 }
53 }
54
pm_policy_latency_request_add(struct pm_policy_latency_request * req,uint32_t value_us)55 void pm_policy_latency_request_add(struct pm_policy_latency_request *req,
56 uint32_t value_us)
57 {
58 req->value_us = value_us;
59
60 k_spinlock_key_t key = k_spin_lock(&latency_lock);
61
62 sys_slist_append(&latency_reqs, &req->node);
63 update_max_latency();
64
65 k_spin_unlock(&latency_lock, key);
66 }
67
pm_policy_latency_request_update(struct pm_policy_latency_request * req,uint32_t value_us)68 void pm_policy_latency_request_update(struct pm_policy_latency_request *req,
69 uint32_t value_us)
70 {
71 k_spinlock_key_t key = k_spin_lock(&latency_lock);
72
73 req->value_us = value_us;
74 update_max_latency();
75
76 k_spin_unlock(&latency_lock, key);
77 }
78
pm_policy_latency_request_remove(struct pm_policy_latency_request * req)79 void pm_policy_latency_request_remove(struct pm_policy_latency_request *req)
80 {
81 k_spinlock_key_t key = k_spin_lock(&latency_lock);
82
83 (void)sys_slist_find_and_remove(&latency_reqs, &req->node);
84 update_max_latency();
85
86 k_spin_unlock(&latency_lock, key);
87 }
88
pm_policy_latency_changed_subscribe(struct pm_policy_latency_subscription * req,pm_policy_latency_changed_cb_t cb)89 void pm_policy_latency_changed_subscribe(struct pm_policy_latency_subscription *req,
90 pm_policy_latency_changed_cb_t cb)
91 {
92 k_spinlock_key_t key = k_spin_lock(&latency_lock);
93
94 req->cb = cb;
95 sys_slist_append(&latency_subs, &req->node);
96
97 k_spin_unlock(&latency_lock, key);
98 }
99
pm_policy_latency_changed_unsubscribe(struct pm_policy_latency_subscription * req)100 void pm_policy_latency_changed_unsubscribe(struct pm_policy_latency_subscription *req)
101 {
102 k_spinlock_key_t key = k_spin_lock(&latency_lock);
103
104 (void)sys_slist_find_and_remove(&latency_subs, &req->node);
105
106 k_spin_unlock(&latency_lock, key);
107 }
108
