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Hardware Mutex Lock (hwspinlock)

Hardware mutex lock.

Device Type​

DEVICE_TYPE_HWSPINLOCK

Structure​

struct hwspinlock_t {
    char * name;
    int base, nlock;
    int (*trylock)(struct hwspinlock_t * hsl, int lock);
    void (*lock)(struct hwspinlock_t * hsl, int lock);
    void (*unlock)(struct hwspinlock_t * hsl, int lock);
    void * priv;
};

struct hwspinlock_desc_t {
    struct hwspinlock_t * hsl;
    int offset;
};

Key API​

FunctionDescription
search_hwspinlock(lock)Find a hardware mutex lock device by global lock number
register_hwspinlock(hsl, drv)Register a hardware mutex lock device
unregister_hwspinlock(hsl)Unregister a hardware mutex lock device
hwspinlock_is_valid(lock)Check whether a global lock number is valid
hwspinlock_trylock(lock)Try to acquire the specified lock
hwspinlock_lock(lock)Acquire the specified lock (busy-wait)
hwspinlock_unlock(lock)Release the specified lock
hwspinlock_desc_alloc(lock)Allocate a lock descriptor
hwspinlock_desc_free(desc)Free a lock descriptor
hwspinlock_desc_trylock/lock/unlock(desc)Operate on the lock via descriptor

Description​

Hardware mutex lock interface. Each device manages a globally numbered lock space (base ~ base + nlock - 1), described in the device tree via the hwspinlock-base and hwspinlock-count properties. Intended for mutual exclusion between processors, and between processors and hardware modules in AMP systems — distinct from the XOS spinlock (xos_spinlock_lock, etc.), which targets SMP in-kernel mutual exclusion. The hwspinlock_desc_t descriptor caches the device pointer and lock offset, suitable for high-frequency locking scenarios by avoiding a global lock number lookup on every operation.