stmhal: Enable micropython.schedule().

ExtInt, Timer and CAN IRQ callbacks are made to work with the scheduler.
They are still hard IRQs by default, but one can now call
micropython.schedule within the hard IRQ to schedule a soft callback.

stmhal/can.c

@@ -865,6 +865,7 @@ void can_rx_irq_handler(uint can_id, uint fifo_id) {
     }
 
     if (callback != mp_const_none) {
+        mp_sched_lock();
         gc_lock();
         nlr_buf_t nlr;
         if (nlr_push(&nlr) == 0) {
@@ -877,6 +878,7 @@ void can_rx_irq_handler(uint can_id, uint fifo_id) {
             mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
         }
         gc_unlock();
+        mp_sched_unlock();
     }
 }
 

stmhal/extint.c

@@ -28,7 +28,6 @@
 #include <stddef.h>
 #include <string.h>
 
-#include "py/nlr.h"
 #include "py/runtime.h"
 #include "py/gc.h"
 #include "py/mphal.h"
@@ -412,6 +411,7 @@ void Handle_EXTI_Irq(uint32_t line) {
         if (line < EXTI_NUM_VECTORS) {
             mp_obj_t *cb = &MP_STATE_PORT(pyb_extint_callback)[line];
             if (*cb != mp_const_none) {
+                mp_sched_lock();
                 // When executing code within a handler we must lock the GC to prevent
                 // any memory allocations.  We must also catch any exceptions.
                 gc_lock();
@@ -427,6 +427,7 @@ void Handle_EXTI_Irq(uint32_t line) {
                     mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
                 }
                 gc_unlock();
+                mp_sched_unlock();
             }
         }
     }

stmhal/mpconfigport.h

@@ -69,6 +69,8 @@
 #define MICROPY_MODULE_WEAK_LINKS   (1)
 #define MICROPY_CAN_OVERRIDE_BUILTINS (1)
 #define MICROPY_USE_INTERNAL_ERRNO  (1)
+#define MICROPY_ENABLE_SCHEDULER    (1)
+#define MICROPY_SCHEDULER_DEPTH     (8)
 #define MICROPY_VFS                 (1)
 #define MICROPY_VFS_FAT             (1)
 
@@ -303,6 +305,8 @@ static inline mp_uint_t disable_irq(void) {
 #if MICROPY_PY_THREAD
 #define MICROPY_EVENT_POLL_HOOK \
     do { \
+        extern void mp_handle_pending(void); \
+        mp_handle_pending(); \
         if (pyb_thread_enabled) { \
             MP_THREAD_GIL_EXIT(); \
             pyb_thread_yield(); \
@@ -312,7 +316,12 @@ static inline mp_uint_t disable_irq(void) {
         } \
     } while (0);
 #else
-#define MICROPY_EVENT_POLL_HOOK            __WFI();
+#define MICROPY_EVENT_POLL_HOOK \
+    do { \
+        extern void mp_handle_pending(void); \
+        mp_handle_pending(); \
+        __WFI(); \
+    } while (0);
 #endif
 
 // There is no classical C heap in bare-metal ports, only Python

stmhal/systick.c

@@ -24,6 +24,7 @@
  * THE SOFTWARE.
  */
 
+#include "py/runtime.h"
 #include "py/mphal.h"
 #include "irq.h"
 #include "systick.h"
@@ -58,6 +59,7 @@ void mp_hal_delay_ms(mp_uint_t Delay) {
         // Wraparound of tick is taken care of by 2's complement arithmetic.
         while (uwTick - start < Delay) {
             // Enter sleep mode, waiting for (at least) the SysTick interrupt.
+            mp_handle_pending();
             #if MICROPY_PY_THREAD
             if (pyb_thread_enabled) {
                 pyb_thread_yield();

stmhal/timer.c

@@ -1363,6 +1363,7 @@ STATIC void timer_handle_irq_channel(pyb_timer_obj_t *tim, uint8_t channel, mp_o
 
             // execute callback if it's set
             if (callback != mp_const_none) {
+                mp_sched_lock();
                 // When executing code within a handler we must lock the GC to prevent
                 // any memory allocations.  We must also catch any exceptions.
                 gc_lock();
@@ -1382,6 +1383,7 @@ STATIC void timer_handle_irq_channel(pyb_timer_obj_t *tim, uint8_t channel, mp_o
                     mp_obj_print_exception(&mp_plat_print, (mp_obj_t)nlr.ret_val);
                 }
                 gc_unlock();
+                mp_sched_unlock();
             }
         }
     }