rp2/mpnetworkport: Refactor out cyw43_has_pending global variable.

A better indication of whether a cyw43 event is pending is the actual flag
in the PendSV handler table. (If this fails, could also use the GPIO
interrupt enabled register bit).

This commit was needed of a previous version of the fix in the parent
commit, but it turned out not strictly necessary for the current version.
However, it's still a good clean up.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

Author: projectgus

ports/rp2/cyw43_configport.h

@@ -140,10 +140,12 @@ uint cyw43_get_pin_wl(cyw43_pin_index_t pin_id);
 #endif
 
 void cyw43_post_poll_hook(void);
-extern volatile int cyw43_has_pending;
+static inline bool cyw43_poll_is_pending(void) {
+    return pendsv_is_pending(PENDSV_DISPATCH_CYW43);
+}
 
 static inline void cyw43_yield(void) {
-    if (!cyw43_has_pending) {
+    if (!cyw43_poll_is_pending()) {
         best_effort_wfe_or_timeout(make_timeout_time_ms(1));
     }
 }

ports/rp2/modmachine.c

@@ -145,7 +145,7 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
 
     uint32_t my_interrupts = MICROPY_BEGIN_ATOMIC_SECTION();
     #if MICROPY_PY_NETWORK_CYW43
-    if (cyw43_has_pending && cyw43_poll != NULL) {
+    if (cyw43_poll_is_pending()) {
         MICROPY_END_ATOMIC_SECTION(my_interrupts);
         return;
     }

ports/rp2/mpnetworkport.c

@@ -57,7 +57,6 @@ static soft_timer_entry_t mp_network_soft_timer;
 #define CYW43_IRQ_LEVEL GPIO_IRQ_LEVEL_HIGH
 #define CYW43_SHARED_IRQ_HANDLER_PRIORITY PICO_SHARED_IRQ_HANDLER_HIGHEST_ORDER_PRIORITY
 
-volatile int cyw43_has_pending = 0;
 
 // The Pico SDK only lets us set GPIO wake on the current running CPU, but the
 // hardware doesn't have this limit. We need to always enable/disable the pin
@@ -89,9 +88,8 @@ static void gpio_irq_handler(void) {
         // cyw43_poll(). It is re-enabled in cyw43_post_poll_hook(), implemented
         // below.
         gpio_set_cpu0_host_wake_irq_enabled(false);
-        cyw43_has_pending = 1;
-        __sev();
         pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, cyw43_poll);
+        __sev();
         CYW43_STAT_INC(IRQ_COUNT);
     }
 }
@@ -106,7 +104,6 @@ void cyw43_irq_init(void) {
 
 // This hook will run on whichever CPU serviced the PendSV interrupt
 void cyw43_post_poll_hook(void) {
-    cyw43_has_pending = 0;
     gpio_set_cpu0_host_wake_irq_enabled(true);
 }
 

ports/rp2/pendsv.c

@@ -99,6 +99,10 @@ static inline int pendsv_suspend_count(void) {
 
 #endif
 
+bool pendsv_is_pending(size_t slot) {
+    return pendsv_dispatch_table[slot] != NULL;
+}
+
 static inline void pendsv_resume_run_dispatch(void) {
     // Run pendsv if needed.  Find an entry with a dispatch and call pendsv dispatch
     // with it.  If pendsv runs it will service all slots.

ports/rp2/pendsv.h

@@ -51,5 +51,6 @@ void pendsv_init(void);
 void pendsv_suspend(void);
 void pendsv_resume(void);
 void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f);
+bool pendsv_is_pending(size_t slot);
 
 #endif // MICROPY_INCLUDED_RP2_PENDSV_H