include/irq.h

/*
 * Copyright (c) 2015 Intel corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file
 * @brief Public interface for configuring interrupts
 */
#ifndef _IRQ_H_
#define _IRQ_H_

/* Pull in the arch-specific implementations */
#include <arch/cpu.h>

#ifndef _ASMLANGUAGE
#include <toolchain/gcc.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup isr_apis Interrupt Service Routine APIs
 * @ingroup kernel_apis
 * @{
 */

/**
 * @brief Initialize an interrupt handler.
 *
 * This routine initializes an interrupt handler for an IRQ. The IRQ must be
 * subsequently enabled before the interrupt handler begins servicing
 * interrupts.
 *
 * @warning
 * Although this routine is invoked at run-time, all of its arguments must be
 * computable by the compiler at build time.
 *
 * @param irq_p IRQ line number.
 * @param priority_p Interrupt priority.
 * @param isr_p Address of interrupt service routine.
 * @param isr_param_p Parameter passed to interrupt service routine.
 * @param flags_p Architecture-specific IRQ configuration flags..
 *
 * @return Interrupt vector assigned to this interrupt.
 */
#define IRQ_CONNECT(irq_p, priority_p, isr_p, isr_param_p, flags_p) \
	_ARCH_IRQ_CONNECT(irq_p, priority_p, isr_p, isr_param_p, flags_p)

/**
 * @brief Lock interrupts.
 *
 * This routine disables all interrupts on the CPU. It returns an unsigned
 * integer "lock-out key", which is an architecture-dependent indicator of
 * whether interrupts were locked prior to the call. The lock-out key must be
 * passed to irq_unlock() to re-enable interrupts.
 *
 * This routine can be called recursively, as long as the caller keeps track
 * of each lock-out key that is generated. Interrupts are re-enabled by
 * passing each of the keys to irq_unlock() in the reverse order they were
 * acquired. (That is, each call to irq_lock() must be balanced by
 * a corresponding call to irq_unlock().)
 *
 * @note
 * This routine can be called by ISRs or by threads. If it is called by a
 * thread, the interrupt lock is thread-specific; this means that interrupts
 * remain disabled only while the thread is running. If the thread performs an
 * operation that allows another thread to run (for example, giving a semaphore
 * or sleeping for N milliseconds), the interrupt lock no longer applies and
 * interrupts may be re-enabled while other processing occurs. When the thread
 * once again becomes the current thread, the kernel re-establishes its
 * interrupt lock; this ensures the thread won't be interrupted until it has
 * explicitly released the interrupt lock it established.
 *
 * @warning
 * The lock-out key should never be used to manually re-enable interrupts
 * or to inspect or manipulate the contents of the CPU's interrupt bits.
 *
 * @return Lock-out key.
 */
#define irq_lock() _arch_irq_lock()

/**
 * @brief Unlock interrupts.
 *
 * This routine reverses the effect of a previous call to irq_lock() using
 * the associated lock-out key. The caller must call the routine once for
 * each time it called irq_lock(), supplying the keys in the reverse order
 * they were acquired, before interrupts are enabled.
 *
 * @note Can be called by ISRs.
 *
 * @param key Lock-out key generated by irq_lock().
 *
 * @return N/A
 */
#define irq_unlock(key) _arch_irq_unlock(key)

/**
 * @brief Enable an IRQ.
 *
 * This routine enables interrupts from source @a irq.
 *
 * @param irq IRQ line.
 *
 * @return N/A
 */
#define irq_enable(irq) _arch_irq_enable(irq)

/**
 * @brief Disable an IRQ.
 *
 * This routine disables interrupts from source @a irq.
 *
 * @param irq IRQ line.
 *
 * @return N/A
 */
#define irq_disable(irq) _arch_irq_disable(irq)

/**
 * @brief Get IRQ enable state.
 *
 * This routine indicates if interrupts from source @a irq are enabled.
 *
 * @param irq IRQ line.
 *
 * @return interrupt enable state, true or false
 */
#define irq_is_enabled(irq) _arch_irq_is_enabled(irq)

/**
 * @}
 */

#ifdef __cplusplus
}
#endif

#endif /* ASMLANGUAGE */
#endif /* _IRQ_H_ */