git.scottworley.com Git - tattlekey/blob - client/tattlekey.c

   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) {
  18   return s->timestamp + (1 << s->send_count) - 1;
  19 }
  20
  21 bool next_send_less_than(void *user_data, pheap_node_id_t a,
  22                          pheap_node_id_t b) {
  23   send_t *sends = (send_t *)user_data;
  24   return next_send(&sends[a]) < next_send(&sends[b]);
  25 }
  26
  27 enum event_type { BUTTONPRESS, SEND };
  28 typedef struct {
  29   enum event_type type;
  30   union {
  31     struct {
  32       uint32_t timestamp;
  33     } buttonpress;
  34   };
  35 } event_t;
  36
  37 queue_t queue;
  38
  39 uint32_t time_s() { return time_us_64() / 1000000ul; }
  40
  41 /* Often we don't bother checking for failure (full queue) because
  42  *   1. The best thing to do in this unfortunate situation is to blithely
  43  *      continue, dropping some events; continuing is better than stopping.
  44  *   2. Neither interrupt context nor queue-processing context can block
  45  *      until space is available, or even sit around & blink the LED to
  46  *      signal a problem.
  47  * (We also get a bit of type safety by taking event_t* rather than void*.) */
  48 static void queue_try_add_ignoring_errors(queue_t *q, event_t *e) {
  49   queue_try_add(q, e);
  50 }
  51
  52 static void button_pressed() {
  53   /* This runs in interrupt context; don't linger.  */
  54   static uint64_t last_button_press_time = 0;
  55   uint32_t now = time_s();
  56   uint32_t time_since_last_press = now - last_button_press_time;
  57   if (time_since_last_press >= config_minimum_seconds_between_button_presses) {
  58     last_button_press_time = now;
  59     event_t e;
  60     e.type = BUTTONPRESS;
  61     e.buttonpress.timestamp = now;
  62     queue_try_add_ignoring_errors(&queue, &e);
  63   }
  64 }
  65
  66 static void time_to_send(uint _) {
  67   /* This runs in interrupt context; don't linger.  */
  68   event_t e;
  69   e.type = SEND;
  70   queue_try_add_ignoring_errors(&queue, &e);
  71 }
  72
  73 void service_sleeps(int alarm, send_t *sleeping_sends, pheap_t *sleeps_heap) {
  74   hardware_alarm_cancel(alarm);
  75
  76   while (1) {
  77     uint32_t now = time_s();
  78     pheap_node_id_t i = ph_peek_head(sleeps_heap);
  79     if (i == 0)
  80       return;
  81     send_t *send = &sleeping_sends[i];
  82     if (next_send(send) > now) {
  83       uint32_t sleep_duration = next_send(send) - now;
  84       if (hardware_alarm_set_target(
  85               alarm, make_timeout_time_ms(sleep_duration * 1000)))
  86         signal_error_by_blinking();
  87       return;
  88     }
  89     if (ph_remove_head(sleeps_heap, false) != i)
  90       signal_error_by_blinking();
  91     uint32_t ago = now - send->timestamp;
  92     send_report(send->seq, ago);
  93     send->send_count++;
  94     if (send->send_count < config_resend_count)
  95       ph_insert_node(sleeps_heap, i);
  96     else
  97       ph_free_node(sleeps_heap, i);
  98   }
  99 }
 100
 101 void service_queue() {
 102   int alarm = hardware_alarm_claim_unused(true);
 103   if (alarm == -1)
 104     signal_error_by_blinking();
 105   hardware_alarm_set_callback(alarm, time_to_send);
 106
 107   send_t sleeping_sends[PICO_PHEAP_MAX_ENTRIES];
 108   pheap_t *sleeps_heap =
 109       ph_create(PICO_PHEAP_MAX_ENTRIES, next_send_less_than, sleeping_sends);
 110   u16_t seq = 0;
 111   while (1) {
 112     service_sleeps(alarm, sleeping_sends, sleeps_heap);
 113
 114     event_t e;
 115     queue_remove_blocking(&queue, &e);
 116     switch (e.type) {
 117     case BUTTONPRESS: {
 118       pheap_node_id_t i = ph_new_node(sleeps_heap);
 119       if (i == 0) {
 120         /* TODO: Don't drop new presses just because sleeps_heap is full of old
 121          * presses. */
 122         break;
 123       }
 124       sleeping_sends[i].timestamp = e.buttonpress.timestamp;
 125       sleeping_sends[i].seq = seq++;
 126       sleeping_sends[i].send_count = 0;
 127       ph_insert_node(sleeps_heap, i);
 128     } break;
 129     case SEND: {
 130       /* OK, we're awake. Cool. Thanks! (We actually do the sends in the
 131        * service_sleeps() call at the top of the loop.)  */
 132     } break;
 133     default:
 134       signal_error_by_blinking();
 135     }
 136   }
 137 }
 138
 139 int main() {
 140   stdio_init_all();
 141   if (cyw43_arch_init_with_country(CYW43_COUNTRY_USA))
 142     signal_error_by_blinking();
 143   cyw43_arch_enable_sta_mode();
 144   signal(3, 100);
 145   if (cyw43_arch_wifi_connect_timeout_ms(config_wifi_ssid, config_wifi_pass,
 146                                          CYW43_AUTH_WPA2_AES_PSK, 90000))
 147     signal_error_by_blinking();
 148   signal(2, 300);
 149
 150   queue_init(&queue, sizeof(event_t), 99);
 151
 152   begin_listening_for_button_press(button_pressed);
 153
 154   service_queue();
 155 }