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1 #include "pico/cyw43_arch.h"
2 #include "pico/stdlib.h"
3 #include "pico/util/pheap.h"
4 #include "pico/util/queue.h"
5
6 #include "blink.h"
7 #include "button.h"
8 #include "config.h"
9 #include "net.h"
10
11 typedef struct {
12 uint32_t timestamp;
13 u16_t seq;
14 u8_t send_count;
15 } send_t;
16
17 uint32_t next_send(send_t *s) { return s->timestamp + s->send_count; }
18
19 bool next_send_less_than(void *user_data, pheap_node_id_t a,
20 pheap_node_id_t b) {
21 send_t *sends = (send_t *)user_data;
22 return next_send(&sends[a]) < next_send(&sends[b]);
23 }
24
25 enum event_type { BUTTONPRESS, SEND };
26 typedef struct {
27 enum event_type type;
28 union {
29 struct {
30 uint32_t timestamp;
31 } buttonpress;
32 };
33 } event_t;
34
35 queue_t queue;
36
37 uint32_t time_s() { return time_us_64() / 1000000ul; }
38
39 /* Often we don't bother checking for failure (full queue) because
40 * 1. The best thing to do in this unfortunate situation is to blithely
41 * continue, dropping some events; continuing is better than stopping.
42 * 2. Neither interrupt context nor queue-processing context can block
43 * until space is available, or even sit around & blink the LED to
44 * signal a problem.
45 * (We also get a bit of type safety by taking event_t* rather than void*.) */
46 static void queue_try_add_ignoring_errors(queue_t *q, event_t *e) {
47 queue_try_add(q, e);
48 }
49
50 static void button_pressed() {
51 /* This runs in interrupt context; don't linger. */
52 static uint64_t last_button_press_time = 0;
53 uint32_t now = time_s();
54 uint32_t time_since_last_press = now - last_button_press_time;
55 if (time_since_last_press >= config_minimum_seconds_between_button_presses) {
56 last_button_press_time = now;
57 event_t e;
58 e.type = BUTTONPRESS;
59 e.buttonpress.timestamp = now;
60 queue_try_add_ignoring_errors(&queue, &e);
61 }
62 }
63
64 static void time_to_send(uint _) {
65 /* This runs in interrupt context; don't linger. */
66 event_t e;
67 e.type = SEND;
68 queue_try_add_ignoring_errors(&queue, &e);
69 }
70
71 void service_sleeps(int alarm, send_t *sleeping_sends, pheap_t *sleeps_heap) {
72 hardware_alarm_cancel(alarm);
73
74 while (1) {
75 uint32_t now = time_s();
76 pheap_node_id_t i = ph_peek_head(sleeps_heap);
77 if (i == 0)
78 return;
79 send_t *send = &sleeping_sends[i];
80 if (next_send(send) > now) {
81 uint32_t sleep_duration = next_send(send) - now;
82 if (hardware_alarm_set_target(
83 alarm, make_timeout_time_ms(sleep_duration * 1000)))
84 signal_error_by_blinking();
85 return;
86 }
87 if (ph_remove_head(sleeps_heap, false) != i)
88 signal_error_by_blinking();
89 uint32_t ago = now - send->timestamp;
90 send_report(send->seq, ago);
91 send->send_count++;
92 if (send->send_count < config_resend_count)
93 ph_insert_node(sleeps_heap, i);
94 else
95 ph_free_node(sleeps_heap, i);
96 }
97 }
98
99 void service_queue() {
100 int alarm = hardware_alarm_claim_unused(true);
101 if (alarm == -1)
102 signal_error_by_blinking();
103 hardware_alarm_set_callback(alarm, time_to_send);
104
105 send_t sleeping_sends[PICO_PHEAP_MAX_ENTRIES];
106 pheap_t *sleeps_heap =
107 ph_create(PICO_PHEAP_MAX_ENTRIES, next_send_less_than, sleeping_sends);
108 u16_t seq = 0;
109 while (1) {
110 service_sleeps(alarm, sleeping_sends, sleeps_heap);
111
112 event_t e;
113 queue_remove_blocking(&queue, &e);
114 switch (e.type) {
115 case BUTTONPRESS: {
116 pheap_node_id_t i = ph_new_node(sleeps_heap);
117 if (i == 0) {
118 /* TODO: Don't drop new presses just because sleeps_heap is full of old
119 * presses. */
120 break;
121 }
122 sleeping_sends[i].timestamp = e.buttonpress.timestamp;
123 sleeping_sends[i].seq = seq++;
124 sleeping_sends[i].send_count = 0;
125 ph_insert_node(sleeps_heap, i);
126 } break;
127 case SEND: {
128 /* OK, we're awake. Cool. Thanks! (We actually do the sends in the
129 * service_sleeps() call at the top of the loop.) */
130 } break;
131 default:
132 signal_error_by_blinking();
133 }
134 }
135 }
136
137 int main() {
138 stdio_init_all();
139 if (cyw43_arch_init_with_country(CYW43_COUNTRY_USA))
140 signal_error_by_blinking();
141 cyw43_arch_enable_sta_mode();
142 signal(3, 100);
143 if (cyw43_arch_wifi_connect_timeout_ms(config_wifi_ssid, config_wifi_pass,
144 CYW43_AUTH_WPA2_AES_PSK, 90000))
145 signal_error_by_blinking();
146 signal(2, 300);
147
148 queue_init(&queue, sizeof(event_t), 99);
149
150 begin_listening_for_button_press(button_pressed);
151
152 service_queue();
153 }