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/*  ictrl.c

 *

 *  This routine installs and handles external interrupt vectors for

 *  PowerPC 403 CPU built-in external interrupt controller

 *

 *  Author: Thomas Doerfler <td@imd.m.isar.de>

 *

 *  COPYRIGHT (c) 1998 by IMD, Puchheim, Germany

 *

 *  To anyone who acknowledges that this file is provided "AS IS"

 *  without any express or implied warranty:

 *      permission to use, copy, modify, and distribute this file

 *      for any purpose is hereby granted without fee, provided that

 *      the above copyright notice and this notice appears in all

 *      copies, and that the name of IMD not be used in

 *      advertising or publicity pertaining to distribution of the

 *      software without specific, written prior permission.

 *      IMD makes no representations about the suitability

 *      of this software for any purpose.

 *

 */

#include "ictrl.h"

#include <rtems.h>

#include <rtems/libio.h>

#include <stdlib.h>                     /* for atexit() */

/*

 *  ISR vector table to dispatch external interrupts

 */

rtems_isr_entry ictrl_vector_table[PPC_IRQ_EXT_MAX];

/*

 *

 *  some utilities to access the EXI* registers

 *

 */

/*

 *  clear bits in EXISR that have a bit set in mask

 */

RTEMS_INLINE_ROUTINE void

clr_exisr(unsigned32 mask)

{

    asm volatile ("mtdcr 0x40,%0"::"r" (mask));/*EXISR*/

}

/*

 *  get value of EXISR

 */

RTEMS_INLINE_ROUTINE unsigned32

get_exisr(void)

{

    unsigned32 val;

    asm volatile ("mfdcr %0,0x40":"=r" (val));/*EXISR*/

    return val;

}

/*

 *  get value of EXIER

 */

RTEMS_INLINE_ROUTINE unsigned32

get_exier(void)

{

    unsigned32 val;

    asm volatile ("mfdcr %0,0x42":"=r" (val));/*EXIER*/

    return val;

}

/*

 *  set value of EXIER

 */

RTEMS_INLINE_ROUTINE void

set_exier(unsigned32 val)

{

    asm volatile ("mtdcr 0x42,%0"::"r" (val));/*EXIER*/

}

/*

 *  enable an external interrupt, make this interrupt consistent

 */

RTEMS_INLINE_ROUTINE void

enable_ext_irq( unsigned32 mask)

{

    unsigned32 isrlvl;

    _CPU_ISR_Disable(isrlvl);

    set_exier(get_exier() | ((mask)&PPC_EXI_MASK));

    _CPU_ISR_Enable(isrlvl);

}

/*

 *  disable an external interrupt, make this interrupt consistent

 */

RTEMS_INLINE_ROUTINE void

disable_ext_irq( unsigned32 mask)

{

    unsigned32 isrlvl;

    _CPU_ISR_Disable(isrlvl);

    set_exier(get_exier() & ~(mask) & PPC_EXI_MASK);

    _CPU_ISR_Enable(isrlvl);

}

/*

 *

 *  this function is called, when a external interrupt is present and

 *  enabled but there is no handler installed. It will clear

 *  the corresponding enable bits and call the spurious handler

 *  present in the CPU Configuration Table, if any.

 *

 */

void

ictrl_spurious_handler(unsigned32 spurious_mask,

                       CPU_Interrupt_frame *cpu_frame)

{

  int v;

  for (v=0; v < PPC_IRQ_EXT_MAX; v++) {

    if (VEC_TO_EXMSK(v) & spurious_mask) {

      clr_exisr(VEC_TO_EXMSK(v));

      disable_ext_irq(VEC_TO_EXMSK(v));

#if 0

      printf("spurious external interrupt: %d at pc 0x%x; disabling\n",

             vector, cpu_frame->Interrupt.pcoqfront);

#endif

      if (rtems_cpu_configuration_get_spurious_handler()) {

        rtems_cpu_configuration_get_spurious_handler()(v + PPC_IRQ_EXT_BASE,cpu_frame);

      }

    }

  }

}

/*

 *  ISR Handler: this is called from the primary exception dispatcher

 */

void

ictrl_isr(rtems_vector_number vector,CPU_Interrupt_frame *cpu_frame)

{

  unsigned32        istat,

                    mask,

                    global_vec;

  int               exvec;

  rtems_isr_entry handler;

  istat = get_exisr() & get_exier() & PPC_EXI_MASK;

  /* FIXME: this may be speeded up using cntlzw instruction */

  for (exvec = 0;exvec < PPC_IRQ_EXT_MAX;exvec++) {

    mask = VEC_TO_EXMSK(exvec);

    if (0 != (istat & mask)) {

      clr_exisr(mask);

      handler = ictrl_vector_table[exvec];

      if (handler) {

        istat &= ~mask;

        global_vec = exvec + PPC_IRQ_EXT_BASE;

        (handler)(global_vec);

      }

    }

  }

  if (istat != 0) { /* anything left? then we have a spurious interrupt */

    ictrl_spurious_handler(istat,cpu_frame);

  }

}

/*

 *

 * the following functions form the user interface

 *

 */

/*

 *

 * install a user vector for one of the external interrupt sources

 *

 */

rtems_status_code

ictrl_set_vector(rtems_isr_entry   new_handler,

                 unsigned32        vector,

                 rtems_isr_entry   *old_handler

)

{

  /*

   *  We put the actual user ISR address in 'ictrl_vector_table'.  This will

   *  be used by the _ictrl_isr so the user gets control.

   */

  /* check for valid vector range */

  if ((vector >= PPC_IRQ_EXT_BASE) &&

      (vector <  PPC_IRQ_EXT_BASE + PPC_IRQ_EXT_MAX)) {

    /* return old handler entry */

    *old_handler = ictrl_vector_table[vector - PPC_IRQ_EXT_BASE];

    if (new_handler != NULL) {

      /* store handler function... */

      ictrl_vector_table[vector - PPC_IRQ_EXT_BASE] = new_handler;

      /* then enable it in EXIER register */

      enable_ext_irq(VEC_TO_EXMSK(vector - PPC_IRQ_EXT_BASE));

    }

    else { /* new_handler == NULL */

      /* then disable it in EXIER register */

      disable_ext_irq(VEC_TO_EXMSK(vector - PPC_IRQ_EXT_BASE));

      ictrl_vector_table[vector - PPC_IRQ_EXT_BASE] = NULL;

    }

    return RTEMS_SUCCESSFUL;

  }

  else {

    return RTEMS_INVALID_NUMBER;

  }

}

/*

 * Called via atexit()

 * deactivate the interrupt controller

 */

void

ictrl_exit(void)

{

  /* mark them all unused */

  disable_ext_irq(~0);

  clr_exisr(~0);

}

/*

 * activate the interrupt controller

 */

rtems_status_code

ictrl_init(void)

{

  proc_ptr dummy;

  /* mark them all unused */

  disable_ext_irq(~0);

  clr_exisr(~0);

  /* install the external interrupt handler */

  _CPU_ISR_install_vector(PPC_IRQ_EXTERNAL,

                          ictrl_isr,

                          &dummy);

  atexit(ictrl_exit);

  return RTEMS_SUCCESSFUL;

}