rp2040: restore the old definitions of these functions

According to
https://developer.arm.com/documentation/dui0662/b/The-Cortex-M0--Processor/Programmers-model/Core-registers
the Cortex M0 lacks the BASEPRI register used to mask low-priority
interrupts. So, we have to use the original version.

Author: jepler

ports/raspberrypi/common-hal/microcontroller/__init__.c

@@ -29,12 +29,29 @@ void common_hal_mcu_delay_us(uint32_t delay) {
     mp_hal_delay_us(delay);
 }
 
+volatile uint32_t nesting_count = 0;
 #ifdef PICO_RP2040
-#include "src/rp2_common/cmsis/stub/CMSIS/Device/RP2040/Include/RP2040.h"
+void common_hal_mcu_disable_interrupts(void) {
+    // We don't use save_and_disable_interrupts() from the sdk because we don't want to worry about PRIMASK.
+    // This is what we do on the SAMD21 via CMSIS.
+    asm volatile ("cpsid i" : : : "memory");
+    __dmb();
+    nesting_count++;
+}
+
+void common_hal_mcu_enable_interrupts(void) {
+    if (nesting_count == 0) {
+        // reset_into_safe_mode(SAFE_MODE_INTERRUPT_ERROR);
+    }
+    nesting_count--;
+    if (nesting_count > 0) {
+        return;
+    }
+    __dmb();
+    asm volatile ("cpsie i" : : : "memory");
+}
 #else
 #include "src/rp2_common/cmsis/stub/CMSIS/Device/RP2350/Include/RP2350.h"
-#endif
-volatile uint32_t nesting_count = 0;
 #define PICO_ELEVATED_IRQ_PRIORITY (0x60) // between PICO_DEFAULT and PIOCO_HIGHEST_IRQ_PRIORITY
 static uint32_t oldBasePri = 0; // 0 (default) masks nothing, other values mask equal-or-larger priority values
 void common_hal_mcu_disable_interrupts(void) {
@@ -64,6 +81,7 @@ void common_hal_mcu_enable_interrupts(void) {
     }
     restore_interrupts(my_interrupts);
 }
+#endif
 
 static bool next_reset_to_bootloader = false;
 

ports/raspberrypi/supervisor/port.c

@@ -52,9 +52,7 @@
 #include "pico/bootrom.h"
 #include "hardware/watchdog.h"
 
-#ifdef PICO_RP2040
-#include "src/rp2_common/cmsis/stub/CMSIS/Device/RP2040/Include/RP2040.h"
-#else
+#ifdef PICO_RP2350
 #include "src/rp2_common/cmsis/stub/CMSIS/Device/RP2350/Include/RP2350.h"
 #endif
 
@@ -503,6 +501,18 @@ void port_interrupt_after_ticks(uint32_t ticks) {
 }
 
 void port_idle_until_interrupt(void) {
+    #ifdef PICO_RP2040
+    common_hal_mcu_disable_interrupts();
+    #if CIRCUITPY_USB_HOST
+    if (!background_callback_pending() && !tud_task_event_ready() && !tuh_task_event_ready() && !_woken_up) {
+    #else
+    if (!background_callback_pending() && !tud_task_event_ready() && !_woken_up) {
+        #endif
+        __DSB();
+        __WFI();
+    }
+    common_hal_mcu_enable_interrupts();
+    #else
     // because we use interrupt priority, don't use
     // common_hal_mcu_disable_interrupts (because an interrupt masked by
     // BASEPRI will not occur)
@@ -526,6 +536,7 @@ void port_idle_until_interrupt(void) {
     __isb();
 
     restore_interrupts(state);
+    #endif
 }
 
 /**