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28 /*=============================================================================
29 VideoCore OS Abstraction Layer - IRQ support
30 =============================================================================*/
39 #include "interface/vcos/vcos_types.h"
45 * \section isr ISR support
47 * API for dispatching interrupts.
52 * Register an interrupt handler. The old handler (if any) is returned in
53 * old_handler. The old handler should be called if the interrupt was not
56 * The handler function will be called in a context with interrupts disabled,
57 * so should be written to be as short as possible. If significant processing
58 * is needed, the handler should delegate to a thread.
60 * The handler function can call any OS primitive that does not block (e.g.
61 * post a semaphore or set an event flag). Blocking operations (including memory
62 * allocation from the system heap) are not permitted.
64 * To deregister an ISR, pass in NULL.
66 * @param vec Vector to register for
67 * @param handler Handler to be called
68 * @param old_handler Updated with the old handler, or NULL.
72 void vcos_register_isr(VCOS_UNSIGNED vec,
73 VCOS_ISR_HANDLER_T handler,
74 VCOS_ISR_HANDLER_T *old_handler);
76 /** Disable interrupts, returning the old value (enabled/disabled) to the caller.
79 VCOS_UNSIGNED vcos_int_disable(void);
81 /** Restore the previous interrupt enable/disable state.
84 void vcos_int_restore(VCOS_UNSIGNED previous);