unix/mpbthciport: Use mp_thread_run_on_mp_thread.

jimmo · jimmo · commit 01a08baec47a · 2023-09-14T16:55:56.000+10:00
This replaces the previous code that used the scheduler (via thread) to
run the BLE host stack.

Now the host stack can run directly on the thread, and then
modbluetooth.c will use mp_thread_run_on_mp_thread to run the
Python-level callbacks on a MicroPython thread as necessary.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared &lt;jim.mussared@gmail.com&gt;
diff --git a/ports/unix/mpbthciport.c b/ports/unix/mpbthciport.c
@@ -34,6 +34,10 @@
 #error Unix HCI UART requires MICROPY_PY_THREAD
 #endif
 
+#if !MICROPY_PY_THREAD_RTOS
+#error Unix HCI UART requires MICROPY_PY_THREAD_RTOS
+#endif
+
 #include "extmod/modbluetooth.h"
 #include "extmod/mpbthci.h"
 
@@ -59,46 +63,25 @@ STATIC int uart_fd = -1;
 // Must be provided by the stack bindings (e.g. mpnimbleport.c or mpbtstackport.c).
 extern bool mp_bluetooth_hci_poll(void);
 
-// For synchronous mode, we run all BLE stack code inside a scheduled task.
-// This task is scheduled periodically (every 1ms) by a background thread.
-
-// Allows the stack to tell us that we should stop trying to schedule.
+// Allows the stack to tell us that we should stop running the hci poll loop.
 extern bool mp_bluetooth_hci_active(void);
 
-// Prevent double-enqueuing of the scheduled task.
-STATIC volatile bool events_task_is_scheduled = false;
-
-STATIC mp_obj_t run_events_scheduled_task(mp_obj_t none_in) {
-    (void)none_in;
-    mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
-    events_task_is_scheduled = false;
-    MICROPY_END_ATOMIC_SECTION(atomic_state);
-    mp_bluetooth_hci_poll();
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(run_events_scheduled_task_obj, run_events_scheduled_task);
-
 STATIC const useconds_t UART_POLL_INTERVAL_US = 1000;
 STATIC pthread_t hci_poll_thread_id;
 
+// We run the host stack periodically (every 1ms) by a background thread.
+// Because MICROPY_PY_THREAD_RTOS is enabled, when the host stack tries
+// to call into Python, it will use mp_thread_run_on_mp_thread to run
+// the callbacks on a Python thread.
 STATIC void *hci_poll_thread(void *arg) {
     (void)arg;
 
-    DEBUG_printf("hci_poll_thread: starting\n");
-
-    events_task_is_scheduled = false;
-
+    // TODO: Replace with select().
     while (mp_bluetooth_hci_active()) {
-        mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
-        if (!events_task_is_scheduled) {
-            events_task_is_scheduled = mp_sched_schedule(MP_OBJ_FROM_PTR(&run_events_scheduled_task_obj), mp_const_none);
-        }
-        MICROPY_END_ATOMIC_SECTION(atomic_state);
+        mp_bluetooth_hci_poll();
         usleep(UART_POLL_INTERVAL_US);
     }
 
-    DEBUG_printf("hci_poll_thread: stopped\n");
-
     return NULL;
 }
 
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
@@ -218,24 +218,31 @@ static inline unsigned long mp_random_seed_init(void) {
 #include <stdio.h>
 #endif
 
-// If threading is enabled, configure the atomic section.
 #if MICROPY_PY_THREAD
+// If threading is enabled, configure the atomic section.
 #define MICROPY_BEGIN_ATOMIC_SECTION() (mp_thread_unix_begin_atomic_section(), 0xffffffff)
 #define MICROPY_END_ATOMIC_SECTION(x) (void)x; mp_thread_unix_end_atomic_section()
+
+// Also enable RTOS support (really, OS in this case).
+#define MICROPY_PY_THREAD_RTOS (1)
 #endif
 
+#include <sched.h>
+
 // In lieu of a WFI(), slow down polling from being a tight loop.
 #ifndef MICROPY_EVENT_POLL_HOOK
 #define MICROPY_EVENT_POLL_HOOK \
     do { \
         extern void mp_handle_pending(bool); \
         mp_handle_pending(true); \
+        MP_THREAD_GIL_EXIT(); \
         usleep(500); /* equivalent to mp_hal_delay_us(500) */ \
+        sched_yield(); \
+        MP_THREAD_GIL_ENTER(); \
     } while (0);
 #endif
 
 // Configure the implementation of machine.idle().
-#include <sched.h>
 #define MICROPY_UNIX_MACHINE_IDLE sched_yield();
 
 #ifndef MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
