Small API additions and minor fixes (#406)

* Add missing DREQ_s

* store actual clock frequency in clock_configure (fixes #368)

* use dma DREQ values defined in dreqs/dma.h

* Fix hw_is_claimed, and add xxx_is_claimed APIs

* Add some PIO irq helper methods

* Add DMA channel IRQ status getter and clear methods

* Implement the correct PIO IRQ status/clear methods (good to have methods here as the h/w interrupt registers are super confusing)

* fix pico_multicore dependencies

* add missing wrapper func __aeabi_f2d

* Further DMA/PIO IRQ API cleanup (and review fixes)

* add PICO_INT64_OPS_IN_RAM flag

src/rp2_common/hardware_sync/include/hardware/sync.h

@@ -384,6 +384,16 @@ void spin_lock_unclaim(uint lock_num);
  */
 int spin_lock_claim_unused(bool required);
 
+/*! \brief Determine if a spin lock is claimed
+ *  \ingroup hardware_sync
+ *
+ * \param lock_num the spin lock number
+ * \return true if claimed, false otherwise
+ * \see spin_lock_claim
+ * \see spin_lock_claim_mask
+ */
+bool spin_lock_is_claimed(uint lock_num);
+
 #define remove_volatile_cast(t, x) ({__mem_fence_acquire(); (t)(x); })
 
 #ifdef __cplusplus

src/rp2_common/hardware_sync/sync.c

@@ -57,3 +57,8 @@ int spin_lock_claim_unused(bool required) {
     return hw_claim_unused_from_range((uint8_t*)&claimed, required, PICO_SPINLOCK_ID_CLAIM_FREE_FIRST, PICO_SPINLOCK_ID_CLAIM_FREE_LAST, "No spinlocks are available");
 }
 
+bool spin_lock_is_claimed(uint lock_num) {
+    check_lock_num(lock_num);
+    return hw_is_claimed((uint8_t *) &claimed, lock_num);
+}
+