[−][src]Crate ruspiro_lock
Atomic locks for Raspberry Pi baremetal systems
This crate provides two options of locks and a data access guard. Spinlock, Semaphore, DataLock. They provide mechanisms to secure cross core access to shared data like MMIO registers of peripherals. As the locks depend on low level atomics they do only work on the Raspberry Pi if the MMU is properly configured. Otherwise using either of the lock functions will hang the core it has been used on.
To share those locking primitives accross the Rasperry Pi cores they should be wrapped in an Arc
.
Usage
Spinlock
use ruspiro_lock::Spinlock; fn main() { let spin = Spinlock::new(); spin.aquire(); // following code is only executed if the lock could be aquired, the executing core pause till then let _ = 10 + 3; spin.release(); }
Semaphore
use ruspiro_lock::Semaphore; fn main() { let sema = Semaphore::new(1); if sema.try_down().is_ok() { // we gained access to the semaphore, do something let _ = 20 /4; sema.up(); } }
DataLock
use ruspiro_lock::DataLock; fn main() { let dalo = DataLock::new(0u32); if let Some(mut data) = dalo.try_lock() { *data = 20; } // once the data goes ot of scope the lock will be released if let Some(data) = dalo.try_lock() { println!("data: {}", *data); // another lock should fail inside this scope assert!(dalo.try_lock().is_none()); } // a blocking lock on the data will block the current execution until the lock get's available let mut data = dalo.lock(); *data = 12; }
Structs
DataLock | An exclusive access lock around the given data |
Semaphore | Simple counting blocking or non-blocking lock |
Spinlock | A blocking cross core lock to guarantee mutual exclusive access. While this lock might block other cores to continue processing this lock should be held as short as possible. Also care shall be taken while using this lock within interrupt handlers, as this might lead to deadlock situations if the lock holding core is interrupted and the interrupt is also trying to aquire the same lock. |
TryDataLock | Result of trying to access the data using |