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

   1 /* tattlekey: A one-key UDP keyboard
   2  * Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "pico/cyw43_arch.h"
  19 #include "pico/stdlib.h"
  20 #include "pico/util/pheap.h"
  21 #include "pico/util/queue.h"
  22
  23 #include "blink.h"
  24 #include "button.h"
  25 #include "config.h"
  26 #include "net.h"
  27 #include "press.h"
  28
  29 enum event_type { NEW_BUTTON_PRESS, RESEND_TIME };
  30 typedef struct {
  31   enum event_type type;
  32   union {
  33     struct {
  34       uint32_t timestamp;
  35     } buttonpress;
  36   };
  37 } event_t;
  38
  39 queue_t queue;
  40
  41 uint32_t time_s() { return time_us_64() / 1000000ul; }
  42
  43 /* Often we don't bother checking for failure (full queue) because
  44  *   1. The best thing to do in this unfortunate situation is to blithely
  45  *      continue, dropping some events; continuing is better than stopping.
  46  *   2. Neither interrupt context nor queue-processing context can block
  47  *      until space is available, or even sit around & blink the LED to
  48  *      signal a problem.
  49  * (We also get a bit of type safety by taking event_t* rather than void*.) */
  50 static void queue_try_add_ignoring_errors(queue_t *q, event_t *e) {
  51   queue_try_add(q, e);
  52 }
  53
  54 static void button_pressed() {
  55   /* This runs in interrupt context; don't linger.  */
  56   static uint64_t last_button_press_time = 0;
  57   uint32_t now = time_s();
  58   uint32_t time_since_last_press = now - last_button_press_time;
  59   if (time_since_last_press >= config_minimum_seconds_between_button_presses) {
  60     last_button_press_time = now;
  61     event_t e;
  62     e.type = NEW_BUTTON_PRESS;
  63     e.buttonpress.timestamp = now;
  64     queue_try_add_ignoring_errors(&queue, &e);
  65   }
  66 }
  67
  68 static void time_to_send(uint _) {
  69   /* This runs in interrupt context; don't linger.  */
  70   event_t e;
  71   e.type = RESEND_TIME;
  72   queue_try_add_ignoring_errors(&queue, &e);
  73 }
  74
  75 void set_resend_alarm(int alarm, uint32_t now, uint32_t next_act_time) {
  76   uint32_t sleep_duration = next_act_time - now;
  77   if (hardware_alarm_set_target(alarm,
  78                                 make_timeout_time_ms(sleep_duration * 1000)))
  79     signal_error_by_blinking();
  80 }
  81
  82 void service_sleeps(int alarm, press_pile_t *pp) {
  83   hardware_alarm_cancel(alarm);
  84
  85   while (1) {
  86     uint32_t now = time_s();
  87     int32_t act_time = next_scheduled_send(pp);
  88     if (act_time == -1)
  89       return;
  90     if (act_time > now) {
  91       set_resend_alarm(alarm, now, act_time);
  92       return;
  93     }
  94     press_t press;
  95     if (!get_press_due_for_resend(pp, now, &press))
  96       signal_error_by_blinking();
  97     u32_t ago = now - press.timestamp;
  98     send_report_packet(press.seq, ago);
  99     press.send_count++;
 100     if (press.send_count < config_resend_count) {
 101       add_press(pp, &press);
 102     }
 103   }
 104 }
 105
 106 void service_queue() {
 107   int alarm = hardware_alarm_claim_unused(true);
 108   if (alarm == -1)
 109     signal_error_by_blinking();
 110   hardware_alarm_set_callback(alarm, time_to_send);
 111
 112   press_pile_t *pp = create_press_pile();
 113   u16_t seq = 0;
 114   while (1) {
 115     service_sleeps(alarm, pp);
 116
 117     event_t e;
 118     queue_remove_blocking(&queue, &e);
 119     switch (e.type) {
 120     case NEW_BUTTON_PRESS: {
 121       add_press(pp, &(press_t){e.buttonpress.timestamp, seq++, 0});
 122       if (seq == 0)
 123         new_epoch();
 124     } break;
 125     case RESEND_TIME: {
 126       /* OK, we're awake. Cool. Thanks! (We actually do the sends in the
 127        * service_sleeps() call at the top of the loop.)  */
 128     } break;
 129     default:
 130       signal_error_by_blinking();
 131     }
 132   }
 133 }
 134
 135 int main() {
 136   stdio_init_all();
 137   if (cyw43_arch_init_with_country(CYW43_COUNTRY_USA))
 138     signal_error_by_blinking();
 139   cyw43_arch_enable_sta_mode();
 140   signal(3, 100);
 141   if (cyw43_arch_wifi_connect_timeout_ms(config_wifi_ssid, config_wifi_pass,
 142                                          CYW43_AUTH_WPA2_AES_PSK, 90000))
 143     signal_error_by_blinking();
 144   signal(2, 300);
 145
 146   queue_init(&queue, sizeof(event_t), 99);
 147
 148   begin_listening_for_button_press(button_pressed);
 149
 150   service_queue();
 151 }