ESP32: improve the execution speed of PWM drivers.

* By moving fast functions to the IRAM
* Replacing divisions by reciprocal multiplication to avoid CPU to issue a DIV.F instruction.

Signed-off-by: Felipe Neves <[email protected]>

Author: uLipe

src/drivers/hardware_specific/esp32/esp32_driver_mcpwm.cpp

@@ -14,7 +14,7 @@
 *  6 PWM independent signals per unit
 *  unit(0/1) > timer(0-2) > operator(0-2) > comparator(0-1) > generator(0-1) > pwm(A/B)
 *
-* -------------------------------------- Table View ----------------------------- 
+* -------------------------------------- Table View -----------------------------
 *
 * group    |  timer  |  operator   | comparator            |  generator    |  pwm
 * --------------------------------------------------------------------------------
@@ -28,31 +28,31 @@
 * ------------------------------------- Example 3PWM ------------------------------
 *                                      ┌─ comparator 0 - generator 0 -> pwm A
 *                       ┌─ operator 0 -|
-*                       |              └─ comparator 1 - generator 1 -> pmw B  
+*                       |              └─ comparator 1 - generator 1 -> pmw B
 *    unit  - timer 0-2 -|
 *    0-1                └─ operator 1 - comparator 0 - generator 0 - pwm C
-*    
+*
 * ------------------------------------- Example 2PWM ------------------------------
 *                                   ┌─ comparator 0 - generator 0 -> pwm A
 *    unit - timer 0-2 - operator 0 -|
-*    0-1                            └─ comparator 1 - generator 1 -> pmw B  
+*    0-1                            └─ comparator 1 - generator 1 -> pmw B
 *
-* -------------------------------------- Example 4PWM ----------------------------- 
+* -------------------------------------- Example 4PWM -----------------------------
 *                                     ┌─ comparator 0 - generator 0 -> pwm A
 *                      ┌─ operator 0 -|
-*                      |              └─ comparator 1 - generator 1 -> pmw B  
-*    unit - timer 0-2 -| 
+*                      |              └─ comparator 1 - generator 1 -> pmw B
+*    unit - timer 0-2 -|
 *    0-1               |              ┌─ comparator 0 - generator 0 -> pwm C
 *                      └─ operator 1 -|
-*                                     └─ comparator 0 - generator 0 -> pwm D   
+*                                     └─ comparator 0 - generator 0 -> pwm D
 
 
 * Complementary mode
 * ------------------
 *  - : 3 pairs of complementary PWM signals per unit
 *  unit(0/1) > timer(0) > operator(0-2) > comparator(0-1) > generator(0-1) > pwm(high/low pair)
-* 
-* -------------------------------------- Table View ----------------------------- 
+*
+* -------------------------------------- Table View -----------------------------
 *
 * group    |  timer  |  operator   | comparator  |  generator    |  pwm
 * ------------------------------------------------------------------------
@@ -63,26 +63,26 @@
 *   0-1    |  0      |  2          |  0          |  0            |  A
 *   0-1    |  0      |  2          |  1          |  1            |  B
 *
-* -------------------------------------- Example 6PWM ----------------------------- 
-*     
+* -------------------------------------- Example 6PWM -----------------------------
+*
 *                                        ┌─ comparator 0 - generator 0 -> pwm A_h
-*                         ┌─ operator 0 -| 
+*                         ┌─ operator 0 -|
 *                         |              └─ comparator 1 - generator 1 -> pmw A_l
-*                         | 
+*                         |
 *     unit                |              ┌─ comparator 0 - generator 0 -> pwm B_h
 *    (group)  -  timer 0 -|- operator 1 -|
 *      0-1                |              └─ comparator 1 - generator 1 -> pmw B_l
 *                         |
 *                         |              ┌─ comparator 0 - generator 0 -> pwm C_h
 *                         └─ operator 2 -|
 *                                        └─ comparator 1 - generator 1 -> pmw C_l
-*   
+*
 
 
 * More info
 * ----------
 * - timers can be associated with any operator, and multiple operators can be associated with the same timer
-* - comparators can be associated with any operator 
+* - comparators can be associated with any operator
 *   - two comparators per operator for independent mode
 *   - one comparator per operator for complementary mode
 * - generators can be associated with any comparator
@@ -96,7 +96,7 @@
 * and here: // https://docs.espressif.com/projects/esp-idf/en/v5.1.4/esp32/migration-guides/release-5.x/5.0/peripherals.html
 */
 
-#include "../../hardware_api.h" 
+#include "../../hardware_api.h"
 
 #if defined(ESP_H) && defined(ARDUINO_ARCH_ESP32) && defined(SOC_MCPWM_SUPPORTED) && !defined(SIMPLEFOC_ESP32_USELEDC)
 
@@ -114,7 +114,7 @@
 
 // MCPWM driver hardware timer pointers
 mcpwm_timer_handle_t timers[2][3] = {NULL};
-// MCPWM timer periods configured (directly related to the pwm frequency) 
+// MCPWM timer periods configured (directly related to the pwm frequency)
 uint32_t pwm_periods[2][3];
 // how many pins from the groups 6 pins is used
 uint8_t group_pins_used[2] = {0};
@@ -143,7 +143,7 @@ uint8_t _findLastTimer(int group){
   // return the last index
   return i;
 }
-// returns the index of the next timer to instantiate 
+// returns the index of the next timer to instantiate
 // -1 if no timers available
 uint8_t _findNextTimer(int group){
   int i = 0;
@@ -157,7 +157,7 @@ uint8_t _findNextTimer(int group){
 
 /*
  * find the best group for the pins
- * if 6pwm 
+ * if 6pwm
  *   - Only option is an an empty group
  * if 3pwm
  *   - Best is an empty group (we can set a pwm frequency)
@@ -180,11 +180,11 @@ uint8_t _findNextTimer(int group){
  * For example if the group has already used 3pwms, there is one generator that has one pwm channel left.
  * If we use this channel we have to use the same timer it has been used with before, so we cannot change the pwm frequency.
  * Current implementation does use the remaining channel only if there isn't other options that would allow changing the pwm frequency.
- * In this example where we have 3pwms already configured, if we try to configure 2pws after, we will skip the remaining channel 
+ * In this example where we have 3pwms already configured, if we try to configure 2pws after, we will skip the remaining channel
  * and use a new timer and operator to allow changing the pwm frequency. In such cases we loose (cannot be used) the remaining channel.
  * TODO: use the pwm_frequency to avoid skipping pwm channels !
  *
- * returns 
+ * returns
  *  - 1 if solution found in one group
  *  - 2 if solution requires using both groups
  *  - 0 if no solution possible
@@ -199,13 +199,13 @@ int _findBestGroup(int no_pins, long pwm_freq, int* group, int* timer){
     }
   }
 
-  // if 3 or 1pwm 
+  // if 3 or 1pwm
   // check if there is available space in one of the groups
   // otherwise fail
   if(no_pins == 3 || no_pins==1){
-    // second best option is if there is a group with 
-    // pair number of pwms available as we can then 
-    // set the pwm frequency 
+    // second best option is if there is a group with
+    // pair number of pwms available as we can then
+    // set the pwm frequency
     for(int i=0; i<SOC_MCPWM_GROUPS; i++){
       if(_hasAvailablePins(i, no_pins+1)) {
         *group=i;
@@ -284,13 +284,13 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
     .pwm_frequency = pwm_frequency,
     .group_id = mcpwm_group
   };
-  
+
   mcpwm_timer_config_t pwm_config;
   pwm_config.group_id = mcpwm_group;
   pwm_config.clk_src = MCPWM_TIMER_CLK_SRC_DEFAULT;
   pwm_config.resolution_hz = _PWM_TIMEBASE_RESOLUTION_HZ;
-  pwm_config.count_mode = MCPWM_TIMER_COUNT_MODE_UP_DOWN;    
-  pwm_config.intr_priority = 0;              
+  pwm_config.count_mode = MCPWM_TIMER_COUNT_MODE_UP_DOWN;
+  pwm_config.intr_priority = 0;
   pwm_config.period_ticks = _calcPWMPeriod(pwm_frequency);
 #ifdef ESP_IDF_VERSION_ABOVE_5_4_0
   pwm_config.flags.allow_pd = 0;
@@ -302,7 +302,7 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
   params->mcpwm_period = pwm_periods[mcpwm_group][timer_no];
 
   uint8_t no_operators = 3; // use 3 comparators one per pair of pwms
-  SIMPLEFOC_ESP32_DRV_DEBUG("Configuring " + String(no_operators) + " operators."); 
+  SIMPLEFOC_ESP32_DRV_DEBUG("Configuring " + String(no_operators) + " operators.");
   mcpwm_operator_config_t operator_config = { .group_id = mcpwm_group };
   operator_config.intr_priority = 0;
   operator_config.flags.update_gen_action_on_tep = true;
@@ -313,9 +313,9 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
   }
 
 #if SIMPLEFOC_ESP32_HW_DEADTIME == true // hardware dead-time (hardware 6pwm)
-  
+
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring 6PWM with hardware dead-time");
-  
+
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring " + String(no_operators) + " comparators.");
   // Create and configure comparators
   mcpwm_comparator_config_t comparator_config = {0};
@@ -324,7 +324,7 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
     CHECK_ERR(mcpwm_new_comparator(params->oper[i], &comparator_config, &params->comparator[i]),"Could not create comparator: " + String(i));
     CHECK_ERR(mcpwm_comparator_set_compare_value(params->comparator[i], (0)), "Could not set duty on comparator: " + String(i));
   }
-  
+
 #else // software dead-time (software 6pwm)
 // software dead-time (software 6pwm)
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring 6PWM with software dead-time");
@@ -339,7 +339,7 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
     CHECK_ERR(mcpwm_new_comparator(params->oper[oper_index], &comparator_config, &params->comparator[i]),"Could not create comparator: " + String(i));
     CHECK_ERR(mcpwm_comparator_set_compare_value(params->comparator[i], (0)), "Could not set duty on comparator: " + String(i));
   }
-#endif 
+#endif
 
   int no_generators = 6; // one per pwm
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring " + String(no_generators) + " generators.");
@@ -355,9 +355,9 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
 
 #if SIMPLEFOC_ESP32_HW_DEADTIME == true // hardware dead-time (hardware 6pwm)
   for (int i = 0; i < no_operators; i++) {
-    CHECK_ERR(_configureCenterAlign(params->generator[2*i],params->comparator[i]), "Failed to configure high-side center align pwm: " + String(2*i));  
-    CHECK_ERR(_configureCenterAlign(params->generator[2*i+1],params->comparator[i]), "Failed to configure low-side center align pwm: " + String(2*i+1));  
-  
+    CHECK_ERR(_configureCenterAlign(params->generator[2*i],params->comparator[i]), "Failed to configure high-side center align pwm: " + String(2*i));
+    CHECK_ERR(_configureCenterAlign(params->generator[2*i+1],params->comparator[i]), "Failed to configure low-side center align pwm: " + String(2*i+1));
+
   }
   // only available for 6pwm
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring dead-time.");
@@ -369,15 +369,15 @@ void* _configure6PWMPinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no,
   mcpwm_dead_time_config_t dt_config_low;
   dt_config_low.posedge_delay_ticks = 0;
   dt_config_low.negedge_delay_ticks = dead_time;
-  dt_config_low.flags.invert_output = SIMPLEFOC_PWM_LOWSIDE_ACTIVE_HIGH; 
+  dt_config_low.flags.invert_output = SIMPLEFOC_PWM_LOWSIDE_ACTIVE_HIGH;
   for (int i = 0; i < no_operators; i++) {
       CHECK_ERR(mcpwm_generator_set_dead_time(params->generator[2*i], params->generator[2*i], &dt_config_high),"Could not set dead time for generator: " + String(i));
       CHECK_ERR(mcpwm_generator_set_dead_time(params->generator[2*i+1], params->generator[2*i+1], &dt_config_low),"Could not set dead time for generator: " + String(i+1));
   }
 #else // software dead-time (software 6pwm)
   for (int i = 0; i < 3; i++) {
-    CHECK_ERR(_configureCenterAlign(params->generator[2*i],params->comparator[2*i], !SIMPLEFOC_PWM_HIGHSIDE_ACTIVE_HIGH), "Failed to configure high-side center align pwm: " + String(2*i));  
-    CHECK_ERR(_configureCenterAlign(params->generator[2*i+1],params->comparator[2*i+1], SIMPLEFOC_PWM_LOWSIDE_ACTIVE_HIGH) , "Failed to configure low-side center align pwm: " + String(2*i+1)); 
+    CHECK_ERR(_configureCenterAlign(params->generator[2*i],params->comparator[2*i], !SIMPLEFOC_PWM_HIGHSIDE_ACTIVE_HIGH), "Failed to configure high-side center align pwm: " + String(2*i));
+    CHECK_ERR(_configureCenterAlign(params->generator[2*i+1],params->comparator[2*i+1], SIMPLEFOC_PWM_LOWSIDE_ACTIVE_HIGH) , "Failed to configure low-side center align pwm: " + String(2*i+1));
   }
 #endif
 
@@ -412,16 +412,16 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
     .pwm_frequency = pwm_frequency,
     .group_id = mcpwm_group
   };
-  
+
   bool shared_timer = false;
   // check if timer is configured
   if (timers[mcpwm_group][timer_no] == NULL){
     mcpwm_timer_config_t pwm_config;
     pwm_config.group_id = mcpwm_group;
     pwm_config.clk_src = MCPWM_TIMER_CLK_SRC_DEFAULT;
     pwm_config.resolution_hz = _PWM_TIMEBASE_RESOLUTION_HZ;
-    pwm_config.count_mode = MCPWM_TIMER_COUNT_MODE_UP_DOWN;    
-    pwm_config.intr_priority = 0;              
+    pwm_config.count_mode = MCPWM_TIMER_COUNT_MODE_UP_DOWN;
+    pwm_config.intr_priority = 0;
     pwm_config.period_ticks = _calcPWMPeriod(pwm_frequency);
 #ifdef ESP_IDF_VERSION_ABOVE_5_4_0
     pwm_config.flags.allow_pd = 0;
@@ -430,10 +430,10 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
     CHECK_ERR(mcpwm_new_timer(&pwm_config, &timers[mcpwm_group][timer_no]), "Could not initialize the timer in group: " + String(mcpwm_group));
     // save variables for later
     pwm_periods[mcpwm_group][timer_no] = pwm_config.period_ticks / 2;
-    params->timers[0] = timers[mcpwm_group][timer_no];    
+    params->timers[0] = timers[mcpwm_group][timer_no];
     // if the numer of used channels it not pair skip one channel
     // the skipped channel cannot be used with the new timer
-    // TODO avoid loosing channels like this 
+    // TODO avoid loosing channels like this
     if(group_pins_used[mcpwm_group] %2) group_pins_used[mcpwm_group]++;
   }else{
     // we will use an already instantiated timer
@@ -446,7 +446,7 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
       return SIMPLEFOC_DRIVER_INIT_FAILED;
     }
     CHECK_ERR(mcpwm_timer_start_stop( params->timers[0], MCPWM_TIMER_STOP_EMPTY), "Failed to stop the timer!");
-    
+
     shared_timer = true;
   }
 
@@ -463,7 +463,7 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
     }
     CHECK_ERR(mcpwm_new_operator(&operator_config, &params->oper[i]),"Could not create operator "+String(i));
     CHECK_ERR(mcpwm_operator_connect_timer(params->oper[i], params->timers[0]),"Could not connect timer to operator: " + String(i));
-  } 
+  }
   // save the last operator in this group
   last_operator[mcpwm_group] = params->oper[no_operators - 1];
 
@@ -485,7 +485,7 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
     int oper_index = shared_timer ? (int)floor((i + 1) / 2) : (int)floor(i / 2);
     CHECK_ERR(mcpwm_new_generator(params->oper[oper_index], &generator_config, &params->generator[i]), "Could not create generator " + String(i) +String(" on pin: ")+String(pins[i]));
   }
-  
+
 
   SIMPLEFOC_ESP32_DRV_DEBUG("Configuring center-aligned pwm.");
   for (int i = 0; i < no_pins; i++) {
@@ -507,15 +507,15 @@ void* _configurePinsMCPWM(long pwm_frequency, int mcpwm_group, int timer_no, int
 }
 
 // function setting the duty cycle to the MCPWM pin
-void _setDutyCycle(mcpwm_cmpr_handle_t cmpr, uint32_t mcpwm_period, float duty_cycle){
+void IRAM_ATTR _setDutyCycle(mcpwm_cmpr_handle_t cmpr, uint32_t mcpwm_period, float duty_cycle){
   float duty = _constrain(duty_cycle, 0.0, 1.0);
   mcpwm_comparator_set_compare_value(cmpr, (uint32_t)(mcpwm_period*duty));
 }
 
 // function setting the duty cycle to the MCPWM pin
 void _forcePhaseState(mcpwm_gen_handle_t generator_high, mcpwm_gen_handle_t generator_low, PhaseState phase_state){
   // phase state is forced in hardware pwm mode
-  // esp-idf docs:  https://docs.espressif.com/projects/esp-idf/en/v5.1.4/esp32/api-reference/peripherals/mcpwm.html#generator-force-actions 
+  // esp-idf docs:  https://docs.espressif.com/projects/esp-idf/en/v5.1.4/esp32/api-reference/peripherals/mcpwm.html#generator-force-actions
   // github issue: https://github.com/espressif/esp-idf/issues/12237
   mcpwm_generator_set_force_level(generator_high, (phase_state == PHASE_ON || phase_state == PHASE_HI) ? -1 : 0, true);
   mcpwm_generator_set_force_level(generator_low, (phase_state == PHASE_ON || phase_state == PHASE_LO) ? -1 : 1, true);