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#ifndef __ALT_LEGACY_IRQ_H__

#define __ALT_LEGACY_IRQ_H__

/******************************************************************************

*                                                                             *

* License Agreement                                                           *

*                                                                             *

* Copyright (c) 2009 Altera Corporation, San Jose, California, USA.           *

* All rights reserved.                                                        *

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* copy of this software and associated documentation files (the "Software"),  *

* to deal in the Software without restriction, including without limitation   *

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*                                                                             *

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* all copies or substantial portions of the Software.                         *

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* of California and by the laws of the United States of America.              *

*                                                                             *

******************************************************************************/

/*

 * This file provides prototypes and inline implementations of certain routines

 * used by the legacy interrupt API. Do not include this in your driver or

 * application source files, use "sys/alt_irq.h" instead to access the proper

 * public API.

 */

#include <errno.h>

#include "system.h"

#ifndef NIOS2_EIC_PRESENT

#include "nios2.h"

#include "alt_types.h"

#include "sys/alt_irq.h"

#ifdef __cplusplus

extern "C"

{

#endif /* __cplusplus */

/*

 * alt_irq_register() can be used to register an interrupt handler. If the

 * function is succesful, then the requested interrupt will be enabled upon

 * return.

 */

extern int alt_irq_register (alt_u32 id,

                             void*   context,

                             alt_isr_func handler);

/*

 * alt_irq_disable() disables the individual interrupt indicated by "id".

 */

static ALT_INLINE int ALT_ALWAYS_INLINE alt_irq_disable (alt_u32 id)

{

  alt_irq_context  status;

  extern volatile alt_u32 alt_irq_active;

  status = alt_irq_disable_all ();

  alt_irq_active &= ~(1 << id);

  NIOS2_WRITE_IENABLE (alt_irq_active);

  alt_irq_enable_all(status);

  return 0;

}

/*

 * alt_irq_enable() enables the individual interrupt indicated by "id".

 */

static ALT_INLINE int ALT_ALWAYS_INLINE alt_irq_enable (alt_u32 id)

{

  alt_irq_context  status;

  extern volatile alt_u32 alt_irq_active;

  status = alt_irq_disable_all ();

  alt_irq_active |= (1 << id);

  NIOS2_WRITE_IENABLE (alt_irq_active);

  alt_irq_enable_all(status);

  return 0;

}

#ifndef ALT_EXCEPTION_STACK

/*

 * alt_irq_initerruptable() should only be called from within an ISR. It is used

 * to allow higer priority interrupts to interrupt the current ISR. The input

 * argument, "priority", is the priority, i.e. interrupt number of the current

 * interrupt.

 *

 * If this function is called, then the ISR is required to make a call to

 * alt_irq_non_interruptible() before returning. The input argument to

 * alt_irq_non_interruptible() is the return value from alt_irq_interruptible().

 *

 * Care should be taken when using this pair of functions, since they increasing

 * the system overhead associated with interrupt handling.

 *

 * If you are using an exception stack then nested interrupts won't work, so

 * these functions are not available in that case.

 */

static ALT_INLINE alt_u32 ALT_ALWAYS_INLINE alt_irq_interruptible (alt_u32 priority)

{

  extern volatile alt_u32 alt_priority_mask;

  extern volatile alt_u32 alt_irq_active;

  alt_u32 old_priority;

  old_priority      = alt_priority_mask;

  alt_priority_mask = (1 << priority) - 1;

  NIOS2_WRITE_IENABLE (alt_irq_active & alt_priority_mask);

  NIOS2_WRITE_STATUS (1);

  return old_priority;

}

/*

 * See Comments above for alt_irq_interruptible() for an explanation of the use of this

 * function.

 */

static ALT_INLINE void ALT_ALWAYS_INLINE alt_irq_non_interruptible (alt_u32 mask)

{

  extern volatile alt_u32 alt_priority_mask;

  extern volatile alt_u32 alt_irq_active;

  NIOS2_WRITE_STATUS (0);

  alt_priority_mask = mask;

  NIOS2_WRITE_IENABLE (mask & alt_irq_active);

}

#endif /* ALT_EXCEPTION_STACK */

#ifdef __cplusplus

}

#endif /* __cplusplus */

#endif /* NIOS2_EIC_PRESENT */

#endif /* __ALT_LEGACY_IRQ_H__ */