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   1 /*
   2  * Copyright © 2023 Keith Packard <keithp@keithp.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 2 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, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include "ao.h"
  20 #include <ao_task.h>
  21
  22 #ifndef HAS_TICK
  23 #define HAS_TICK 1
  24 #endif
  25
  26 volatile AO_TICK_TYPE ao_tick_count;
  27
  28 AO_TICK_TYPE
  29 ao_time(void)
  30 {
  31         return ao_tick_count;
  32 }
  33
  34 uint64_t
  35 ao_time_ns(void)
  36 {
  37         AO_TICK_TYPE    before, after;
  38         uint32_t        val;
  39
  40         do {
  41                 before = ao_tick_count;
  42                 val = stm_systick.val;
  43                 after = ao_tick_count;
  44         } while (before != after);
  45
  46         return (uint64_t) after * (1000000000ULL / AO_HERTZ) +
  47                 (uint64_t) val * (1000000000ULL / AO_SYSTICK);
  48 }
  49
  50 #if AO_DATA_ALL
  51 volatile uint8_t        ao_data_interval = 1;
  52 volatile uint8_t        ao_data_count;
  53 #endif
  54
  55 void stm_systick_isr(void)
  56 {
  57         if (stm_systick.ctrl & (1 << STM_SYSTICK_CTRL_COUNTFLAG)) {
  58                 ++ao_tick_count;
  59                 ao_task_check_alarm();
  60 #if AO_DATA_ALL
  61                 if (++ao_data_count == ao_data_interval && ao_data_interval) {
  62                         ao_data_count = 0;
  63 #if HAS_FAKE_FLIGHT
  64                         if (ao_fake_flight_active)
  65                                 ao_fake_flight_poll();
  66                         else
  67 #endif
  68                                 ao_adc_poll();
  69 #if (AO_DATA_ALL & ~(AO_DATA_ADC))
  70                         ao_wakeup((void *) &ao_data_count);
  71 #endif
  72                 }
  73 #endif
  74 #ifdef AO_TIMER_HOOK
  75                 AO_TIMER_HOOK;
  76 #endif
  77         }
  78 }
  79
  80 #if HAS_ADC
  81 void
  82 ao_timer_set_adc_interval(uint8_t interval)
  83 {
  84         ao_arch_critical(
  85                 ao_data_interval = interval;
  86                 ao_data_count = 0;
  87                 );
  88 }
  89 #endif
  90
  91 #define SYSTICK_RELOAD (AO_SYSTICK / 100 - 1)
  92
  93 void
  94 ao_timer_init(void)
  95 {
  96         stm_systick.load = SYSTICK_RELOAD;
  97         stm_systick.val = 0;
  98         stm_systick.ctrl = ((1 << STM_SYSTICK_CTRL_ENABLE) |
  99                             (1 << STM_SYSTICK_CTRL_TICKINT) |
 100                             (STM_SYSTICK_CTRL_CLKSOURCE_HCLK_8 << STM_SYSTICK_CTRL_CLKSOURCE));
 101         stm_scb.shpr3 |= (uint32_t) AO_STM_NVIC_CLOCK_PRIORITY << 24;
 102 }