rp2: Sleep changes.

Stop using soft timer for mp_wfe_or_timeout. Now uses the alarm pool
again as issues with this code have been fixed. This resolves the "sev"
issue that stops the rp2 port going idle.

Change the sleep code to use the hardware timer library and alarm 1 as
alarm 2 is used by and soft timers and 3 is used by the alarm pool

Signed-off-by: Peter Harper <[email protected]>

Author: peterharperuk

ports/rp2/modmachine.c

@@ -121,6 +121,9 @@ static void mp_machine_idle(void) {
     MICROPY_INTERNAL_WFE(1);
 }
 
+static void alarm_sleep_callback(uint alarm_id) {
+}
+
 static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     mp_int_t delay_ms = 0;
     bool use_timer_alarm = false;
@@ -190,22 +193,17 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     // Disable ROSC.
     rosc_hw->ctrl = ROSC_CTRL_ENABLE_VALUE_DISABLE << ROSC_CTRL_ENABLE_LSB;
 
+    // pico-sdk alarm pool uses 3
+    // micropython soft timers use 2
+    int alarm_num = 1;
     if (n_args == 0) {
         #if MICROPY_PY_NETWORK_CYW43
         gpio_set_dormant_irq_enabled(CYW43_PIN_WL_HOST_WAKE, GPIO_IRQ_LEVEL_HIGH, true);
         #endif
         xosc_dormant();
     } else {
-        bool timer3_enabled = irq_is_enabled(3);
-
-        const uint32_t alarm_num = 3;
-        const uint32_t irq_num = TIMER_ALARM_IRQ_NUM(timer_hw, alarm_num);
+        hardware_alarm_claim(alarm_num);
         if (use_timer_alarm) {
-            // Make sure ALARM3/IRQ3 is enabled on _this_ core
-            if (!timer3_enabled) {
-                irq_set_enabled(irq_num, true);
-            }
-            hw_set_bits(&timer_hw->inte, 1u << alarm_num);
             // Use timer alarm to wake.
             clocks_hw->sleep_en0 = 0x0;
             #if PICO_RP2040
@@ -215,8 +213,12 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
             #else
             #error Unknown processor
             #endif
-            timer_hw->intr = 1u << alarm_num; // clear any IRQ
-            timer_hw->alarm[alarm_num] = timer_hw->timerawl + delay_ms * 1000;
+            hardware_alarm_set_callback(alarm_num, alarm_sleep_callback);
+            if (hardware_alarm_set_target(alarm_num, make_timeout_time_ms(delay_ms))) {
+                hardware_alarm_set_callback(alarm_num, NULL);
+                hardware_alarm_unclaim(alarm_num);
+                alarm_num = -1;
+            }
         } else {
             // TODO: Use RTC alarm to wake.
             clocks_hw->sleep_en0 = 0x0;
@@ -246,11 +248,10 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
         #endif
 
         // Go into low-power mode.
-        __wfi();
-
-        if (!timer3_enabled) {
-            irq_set_enabled(irq_num, false);
+        if (alarm_num >= 0) {
+            __wfi();
         }
+
         clocks_hw->sleep_en0 |= ~(0u);
         clocks_hw->sleep_en1 |= ~(0u);
     }
@@ -264,6 +265,11 @@ static void mp_machine_lightsleep(size_t n_args, const mp_obj_t *args) {
 
     // Re-sync mp_hal_time_ns() counter with aon timer.
     mp_hal_time_ns_set_from_rtc();
+    if (alarm_num >= 0) {
+        hardware_alarm_cancel(alarm_num);
+        hardware_alarm_set_callback(alarm_num, NULL);
+        hardware_alarm_unclaim(alarm_num);
+    }
 }
 
 NORETURN static void mp_machine_deepsleep(size_t n_args, const mp_obj_t *args) {

ports/rp2/mphalport.c

@@ -266,15 +266,5 @@ void soft_timer_init(void) {
 }
 
 void mp_wfe_or_timeout(uint32_t timeout_ms) {
-    soft_timer_entry_t timer;
-
-    // Note the timer doesn't have an associated callback, it just exists to create a
-    // hardware interrupt to wake the CPU
-    soft_timer_static_init(&timer, SOFT_TIMER_MODE_ONE_SHOT, 0, NULL);
-    soft_timer_insert(&timer, timeout_ms);
-
-    __wfe();
-
-    // Clean up the timer node if it's not already
-    soft_timer_remove(&timer);
+    best_effort_wfe_or_timeout(delayed_by_ms(get_absolute_time(), timeout_ms));
 }