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   1 /*
   2  * Copyright © 2024 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 #include <ao.h>
  19 #include <ao_fast_timer.h>
  20
  21 static void (*ao_fast_timer_callback[AO_FAST_TIMER_MAX])(void);
  22 static uint8_t ao_fast_timer_count;
  23 static uint8_t ao_fast_timer_users;
  24
  25 #if AO_FAST_TIMER == 1
  26
  27 # define AO_FAST_TIMER_TYPE 18
  28 # define stm_tim                stm_tim1
  29 # define stm_tim_isr            stm_tim1_up_isr
  30 # define STM_ISR_TIM_POS        STM_ISR_TIM1_UP_POS
  31 # define STM_RCC_APBENR_TIMEN   STM_RCC_APB2ENR_TIM1EN
  32
  33 #elif AO_FAST_TIMER == 2
  34
  35 # define AO_FAST_TIMER_TYPE 234
  36 # define stm_tim                stm_tim2
  37 # define stm_tim_isr            stm_tim2_isr
  38 # define STM_ISR_TIM_POS        STM_ISR_TIM2_POS
  39 # define STM_RCC_APBENR_TIMEN   STM_RCC_APB1ENR_TIM2EN
  40
  41 #elif AO_FAST_TIMER == 3
  42
  43 # define AO_FAST_TIMER_TYPE 234
  44 # define stm_tim                stm_tim3
  45 # define stm_tim_isr            stm_tim3_isr
  46 # define STM_ISR_TIM_POS        STM_ISR_TIM3_POS
  47 # define STM_RCC_APBENR_TIMEN   STM_RCC_APB1ENR_TIM3EN
  48
  49 #elif AO_FAST_TIMER == 4
  50
  51 # define AO_FAST_TIMER_TYPE 234
  52 # define stm_tim                stm_tim4
  53 # define stm_tim_isr            stm_tim4_isr
  54 # define STM_ISR_TIM_POS        STM_ISR_TIM4_POS
  55 # define STM_RCC_APBENR_TIMEN   STM_RCC_APB1ENR_TIM4EN
  56
  57 #else
  58 #error AO_FAST_TIMER
  59 #endif
  60
  61 #if AO_FAST_TIMER_TYPE == 18
  62
  63 #define STM_TIM_CR1(cen) ((0 << STM_TIM18_CR1_CKD) |    \
  64                           (0 << STM_TIM18_CR1_ARPE) |   \
  65                           (0 << STM_TIM18_CR1_CMS) |    \
  66                           (0 << STM_TIM18_CR1_DIR) |    \
  67                           (0 << STM_TIM18_CR1_OPM) |    \
  68                           (1 << STM_TIM18_CR1_URS) |    \
  69                           (0 << STM_TIM18_CR1_UDIS) |   \
  70                           ((cen) << STM_TIM18_CR1_CEN))
  71 #define STM_TIM_SR_UIF          STM_TIM18_SR_UIF
  72 #define STM_TIM_DIER_UIE        STM_TIM18_DIER_UIE
  73 #define STM_TIM_EGR_UG          STM_TIM18_EGR_UG
  74 #define STM_TIM_CR2_MMS         STM_TIM18_CR2_MMS
  75 #define STM_TIM_CR2_MMS_RESET   STM_TIM18_CR2_MMS_RESET
  76
  77 #define AO_TIM_PCLK     AO_PCLK2
  78
  79 /*
  80  * According to the STM clock-configuration, timers 18 run
  81  * twice as fast as the APB2 clock *if* the APB2 prescaler
  82  * is greater than 1.
  83  */
  84
  85 #if AO_APB2_PRESCALER > 1
  86 #define AO_TIM_SCALER 2
  87 #else
  88 #define AO_TIM_SCALER 1
  89 #endif
  90
  91 #define STM_RCC_APB_TIM stm_rcc.apb2enr
  92
  93 #elif AO_FAST_TIMER_TYPE == 234
  94
  95 #define STM_TIM_CR1(cen) ((STM_TIM234_CR1_CKD_1 << STM_TIM234_CR1_CKD) | \
  96                           (0 << STM_TIM234_CR1_ARPE) |                  \
  97                           (STM_TIM234_CR1_CMS_EDGE << STM_TIM234_CR1_CMS) | \
  98                           (0 << STM_TIM234_CR1_DIR) |                   \
  99                           (0 << STM_TIM234_CR1_OPM) |                   \
 100                           (0 << STM_TIM234_CR1_URS) |                   \
 101                           (0 << STM_TIM234_CR1_UDIS) |                  \
 102                           ((cen) << STM_TIM234_CR1_CEN))                \
 103
 104 #define AO_TIM_PCLK     AO_PCLK1
 105
 106 /*
 107  * According to the STM clock-configuration, timers 234 run
 108  * twice as fast as the APB1 clock *if* the APB1 prescaler
 109  * is greater than 1.
 110  */
 111
 112 #if AO_APB1_PRESCALER > 1
 113 #define AO_TIM_SCALER 2
 114 #else
 115 #define AO_TIM_SCALER 1
 116 #endif
 117
 118 #define STM_TIM_SR_UIF          STM_TIM234_SR_UIF
 119 #define STM_TIM_DIER_UIE        STM_TIM234_DIER_UIE
 120 #define STM_TIM_EGR_UG          STM_TIM234_EGR_UG
 121 #define STM_TIM_CR2_MMS         STM_TIM234_CR2_MMS
 122 #define STM_TIM_CR2_MMS_RESET   STM_TIM234_CR2_MMS_RESET
 123
 124 #define STM_RCC_APB_TIM stm_rcc.apb1enr
 125
 126 #endif
 127
 128 static void
 129 ao_fast_timer_enable(void)
 130 {
 131         stm_tim.cr1 = STM_TIM_CR1(1);
 132 }
 133
 134 static void
 135 ao_fast_timer_disable(void)
 136 {
 137         stm_tim.cr1 = STM_TIM_CR1(0);
 138 }
 139
 140 void
 141 ao_fast_timer_on(void (*callback)(void))
 142 {
 143         ao_fast_timer_callback[ao_fast_timer_count] = callback;
 144         if (!ao_fast_timer_count++)
 145                 ao_fast_timer_enable();
 146 }
 147
 148 void
 149 ao_fast_timer_off(void (*callback)(void))
 150 {
 151         uint8_t n;
 152
 153         for (n = 0; n < ao_fast_timer_count; n++)
 154                 if (ao_fast_timer_callback[n] == callback) {
 155                         for (; n < ao_fast_timer_count-1; n++) {
 156                                 ao_fast_timer_callback[n] = ao_fast_timer_callback[n+1];
 157                         }
 158                         if (!--ao_fast_timer_count)
 159                                 ao_fast_timer_disable();
 160                         break;
 161                 }
 162 }
 163
 164 void stm_tim_isr(void)
 165 {
 166         uint8_t i;
 167         if (stm_tim.sr & (1 << STM_TIM_SR_UIF)) {
 168                 stm_tim.sr = 0;
 169
 170                 for (i = 0; i < ao_fast_timer_count; i++)
 171                         (*ao_fast_timer_callback[i])();
 172         }
 173 }
 174
 175 #ifndef FAST_TIMER_FREQ
 176 #define FAST_TIMER_FREQ 10000
 177 #endif
 178
 179 #define TIMER_FAST      ((AO_TIM_PCLK * AO_TIM_SCALER) / FAST_TIMER_FREQ)
 180
 181 void
 182 ao_fast_timer_init(void)
 183 {
 184         if (!ao_fast_timer_users) {
 185                 stm_nvic_set_enable(STM_ISR_TIM_POS);
 186                 stm_nvic_set_priority(STM_ISR_TIM_POS, AO_STM_NVIC_CLOCK_PRIORITY);
 187
 188                 /* Turn on timer 1 */
 189                 STM_RCC_APB_TIM |= (1 << STM_RCC_APBENR_TIMEN);
 190
 191                 stm_tim.psc = TIMER_FAST;
 192                 stm_tim.arr = 9;
 193                 stm_tim.cnt = 0;
 194
 195                 /* Enable update interrupt */
 196                 stm_tim.dier = (1 << STM_TIM_DIER_UIE);
 197
 198                 /* Poke timer to reload values */
 199                 stm_tim.egr |= (1 << STM_TIM_EGR_UG);
 200
 201                 stm_tim.cr2 = (STM_TIM_CR2_MMS_RESET << STM_TIM_CR2_MMS);
 202                 ao_fast_timer_disable();
 203         }
 204         if (ao_fast_timer_users == AO_FAST_TIMER_MAX)
 205                 ao_panic(AO_PANIC_FAST_TIMER);
 206         ao_fast_timer_users++;
 207 }
 208