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#ifndef __ALT_IRQ_H__

#define __ALT_IRQ_H__

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

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* License Agreement                                                           *

*                                                                             *

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

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

/*

 * alt_irq.h is the Nios II specific implementation of the interrupt controller

 * interface.

 *

 * Nios II includes optional support for an external interrupt controller.

 * When an external controller is present, the "Enhanced" interrupt API

 * must be used to manage individual interrupts. The enhanced API also

 * supports the processor's internal interrupt controller. Certain API

 * members are accessible from either the "legacy" or "enhanced" interrpt

 * API.

 *

 * Regardless of which API is in use, this file should be included by

 * application code and device drivers that register ISRs or manage interrpts.

 */

#include <errno.h>

#include "nios2.h"

#include "alt_types.h"

#include "system.h"

#ifdef __cplusplus

extern "C"

{

#endif /* __cplusplus */

/*

 * Macros used by alt_irq_enabled

 */

#define ALT_IRQ_ENABLED  1

#define ALT_IRQ_DISABLED 0  

/*

 * Number of available interrupts in internal interrupt controller.

 */

#define ALT_NIRQ NIOS2_NIRQ

/*

 * Used by alt_irq_disable_all() and alt_irq_enable_all().

 */

typedef int alt_irq_context;

/* ISR Prototype */

#ifdef ALT_ENHANCED_INTERRUPT_API_PRESENT

typedef void (*alt_isr_func)(void* isr_context);

#else

typedef void (*alt_isr_func)(void* isr_context, alt_u32 id);

#endif

/*

 * The following protypes and routines are supported by both

 * the enhanced and legacy interrupt APIs

 */

/*

 * alt_irq_enabled can be called to determine if the processor's global

 * interrupt enable is asserted. The return value is zero if interrupts

 * are disabled, and non-zero otherwise.

 *

 * Whether the internal or external interrupt controller is present,

 * individual interrupts may still be disabled. Use the other API to query

 * a specific interrupt.

 */

static ALT_INLINE int ALT_ALWAYS_INLINE alt_irq_enabled (void)

{

  int status;

  NIOS2_READ_STATUS (status);

  return status & NIOS2_STATUS_PIE_MSK;

}

/*

 * alt_irq_disable_all()

 *

 * This routine inhibits all interrupts by negating the status register PIE

 * bit. It returns the previous contents of the CPU status register (IRQ

 * context) which can be used to restore the status register PIE bit to its

 * state before this routine was called.

 */

static ALT_INLINE alt_irq_context ALT_ALWAYS_INLINE

       alt_irq_disable_all (void)

{

  alt_irq_context context;

  NIOS2_READ_STATUS (context);

  NIOS2_WRITE_STATUS (context & ~NIOS2_STATUS_PIE_MSK);

  return context;

}

/*

 * alt_irq_enable_all()

 *

 * Enable all interrupts that were previously disabled by alt_irq_disable_all()

 *

 * This routine accepts a context to restore the CPU status register PIE bit

 * to the state prior to a call to alt_irq_disable_all().

 * In the case of nested calls to alt_irq_disable_all()/alt_irq_enable_all(),

 * this means that alt_irq_enable_all() does not necessarily re-enable

 * interrupts.

 *

 * This routine will perform a read-modify-write sequence to restore only

 * status.PIE if the processor is configured with options that add additional

 * writeable status register bits. These include the MMU, MPU, the enhanced

 * interrupt controller port, and shadow registers. Otherwise, as a performance

 * enhancement, status is overwritten with the prior context.

 */

static ALT_INLINE void ALT_ALWAYS_INLINE

       alt_irq_enable_all (alt_irq_context context)

{

#if (NIOS2_NUM_OF_SHADOW_REG_SETS > 0) || (defined NIOS2_EIC_PRESENT) || \

    (defined NIOS2_MMU_PRESENT) || (defined NIOS2_MPU_PRESENT)

  alt_irq_context status;

  NIOS2_READ_STATUS (status);

  status &= ~NIOS2_STATUS_PIE_MSK;

  status |= (context & NIOS2_STATUS_PIE_MSK);

  NIOS2_WRITE_STATUS (status);

#else

  NIOS2_WRITE_STATUS (context);

#endif

}

/*

 * The function alt_irq_init() is defined within the auto-generated file

 * alt_sys_init.c. This function calls the initilization macros for all

 * interrupt controllers in the system at config time, before any other

 * non-interrupt controller driver is initialized.

 *

 * The "base" parameter is ignored and only present for backwards-compatibility.

 * It is recommended that NULL is passed in for the "base" parameter.

 */

extern void alt_irq_init (const void* base);

/*

 * alt_irq_cpu_enable_interrupts() enables the CPU to start taking interrupts.

 */

static ALT_INLINE void ALT_ALWAYS_INLINE

       alt_irq_cpu_enable_interrupts ()

{

    NIOS2_WRITE_STATUS(NIOS2_STATUS_PIE_MSK

#if defined(NIOS2_EIC_PRESENT) && (NIOS2_NUM_OF_SHADOW_REG_SETS > 0)

    | NIOS2_STATUS_RSIE_MSK

#endif      

      );

}

/*

 * Prototypes for the enhanced interrupt API.

 */

#ifdef ALT_ENHANCED_INTERRUPT_API_PRESENT

/*

 * alt_ic_isr_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_ic_isr_register(alt_u32 ic_id,

                        alt_u32 irq,

                        alt_isr_func isr,

                        void *isr_context,

                        void *flags);

/*

 * alt_ic_irq_enable() and alt_ic_irq_disable() enable/disable a specific

 * interrupt by using IRQ port and interrupt controller instance.

 */

int alt_ic_irq_enable (alt_u32 ic_id, alt_u32 irq);

int alt_ic_irq_disable(alt_u32 ic_id, alt_u32 irq);

 /*

 * alt_ic_irq_enabled() indicates whether a specific interrupt, as

 * specified by IRQ port and interrupt controller instance is enabled.

 */

alt_u32 alt_ic_irq_enabled(alt_u32 ic_id, alt_u32 irq);

#else 

/*

 * Prototypes for the legacy interrupt API.

 */

#include "priv/alt_legacy_irq.h"

#endif 

/*

 * alt_irq_pending() returns a bit list of the current pending interrupts.

 * This is used by alt_irq_handler() to determine which registered interrupt

 * handlers should be called.

 *

 * This routine is only available for the Nios II internal interrupt

 * controller.

 */

#ifndef NIOS2_EIC_PRESENT

static ALT_INLINE alt_u32 ALT_ALWAYS_INLINE alt_irq_pending (void)

{

  alt_u32 active;

  NIOS2_READ_IPENDING (active);

  return active;

}

#endif 

#ifdef __cplusplus

}

#endif /* __cplusplus */

#endif /* __ALT_IRQ_H__ */