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static __force_inline void | __sev (void) |
| | Insert a SEV instruction in to the code path.The SEV (send event) instruction sends an event to both cores.
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static __force_inline void | __wfe (void) |
| | Insert a WFE instruction in to the code path.The WFE (wait for event) instruction waits until one of a number of events occurs, including events signalled by the SEV instruction on either core.
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static __force_inline void | __wfi (void) |
| | Insert a WFI instruction in to the code path.The WFI (wait for interrupt) instruction waits for a interrupt to wake up the core.
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static __force_inline void | __dmb (void) |
| | Insert a DMB instruction in to the code path.The DMB (data memory barrier) acts as a memory barrier, all memory accesses prior to this instruction will be observed before any explicit access after the instruction.
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static __force_inline void | __dsb (void) |
| | Insert a DSB instruction in to the code path.The DSB (data synchronization barrier) acts as a special kind of data memory barrier (DMB). The DSB operation completes when all explicit memory accesses before this instruction complete.
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static __force_inline void | __isb (void) |
| | Insert a ISB instruction in to the code path.ISB acts as an instruction synchronization barrier. It flushes the pipeline of the processor, so that all instructions following the ISB are fetched from cache or memory again, after the ISB instruction has been completed.
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static __force_inline void | __mem_fence_acquire (void) |
| | Acquire a memory fence.
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static __force_inline void | __mem_fence_release (void) |
| | Release a memory fence.
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| static __force_inline uint32_t | save_and_disable_interrupts (void) |
| | Save and disable interrupts. More...
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| static __force_inline void | restore_interrupts (uint32_t status) |
| | Restore interrupts to a specified state. More...
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| static __force_inline spin_lock_t * | spin_lock_instance (uint lock_num) |
| | Get HW Spinlock instance from number. More...
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| static __force_inline uint | spin_lock_get_num (spin_lock_t *lock) |
| | Get HW Spinlock number from instance. More...
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| static __force_inline void | spin_lock_unsafe_blocking (spin_lock_t *lock) |
| | Acquire a spin lock without disabling interrupts (hence unsafe) More...
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| static __force_inline void | spin_unlock_unsafe (spin_lock_t *lock) |
| | Release a spin lock without re-enabling interrupts. More...
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| static __force_inline uint32_t | spin_lock_blocking (spin_lock_t *lock) |
| | Acquire a spin lock safelyThis function will disable interrupts prior to acquiring the spinlock. More...
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| static bool | is_spin_locked (spin_lock_t *lock) |
| | Check to see if a spinlock is currently acquired elsewhere. More...
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| static __force_inline void | spin_unlock (spin_lock_t *lock, uint32_t saved_irq) |
| | Release a spin lock safelyThis function will re-enable interrupts according to the parameters. More...
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| spin_lock_t * | spin_lock_init (uint lock_num) |
| | Initialise a spin lockThe spin lock is initially unlocked. More...
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void | spin_locks_reset (void) |
| | Release all spin locks.
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| uint | next_striped_spin_lock_num (void) |
| | Return a spin lock number from the striped rangeReturns a spin lock number in the range PICO_SPINLOCK_ID_STRIPED_FIRST to PICO_SPINLOCK_ID_STRIPED_LAST in a round robin fashion. This does not grant the caller exclusive access to the spin lock, so the caller must: More...
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| void | spin_lock_claim (uint lock_num) |
| | Mark a spin lock as usedMethod for cooperative claiming of hardware. Will cause a panic if the spin lock is already claimed. Use of this method by libraries detects accidental configurations that would fail in unpredictable ways. More...
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| void | spin_lock_claim_mask (uint32_t lock_num_mask) |
| | Mark multiple spin locks as usedMethod for cooperative claiming of hardware. Will cause a panic if any of the spin locks are already claimed. Use of this method by libraries detects accidental configurations that would fail in unpredictable ways. More...
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| void | spin_lock_unclaim (uint lock_num) |
| | Mark a spin lock as no longer usedMethod for cooperative claiming of hardware. More...
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| int | spin_lock_claim_unused (bool required) |
| | Claim a free spin lock. More...
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| bool | spin_lock_is_claimed (uint lock_num) |
| | Determine if a spin lock is claimed. More...
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The RP2040 provides 32 hardware spin locks, which can be used to manage mutually-exclusive access to shared software and hardware resources.
Generally each spin lock itself is a shared resource, i.e. the same hardware spin lock can be used by multiple higher level primitives (as long as the spin locks are neither held for long periods, nor held concurrently with other spin locks by the same core - which could lead to deadlock). A hardware spin lock that is exclusively owned can be used individually without more flexibility and without regard to other software. Note that no hardware spin lock may be acquired re-entrantly (i.e. hardware spin locks are not on their own safe for use by both thread code and IRQs) however the default spinlock related methods here (e.g. spin_lock_blocking) always disable interrupts while the lock is held as use by IRQ handlers and user code is common/desirable, and spin locks are only expected to be held for brief periods.
The SDK uses the following default spin lock assignments, classifying which spin locks are reserved for exclusive/special purposes vs those suitable for more general shared use:
v1.5.0