irq.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 *
 *  This file contains the implementation of the function described in irq.h
 *
 *  Copyright (C) 1998, 1999 [e-mail]
 *
 *  The license and distribution terms for this file may be
 *  found in found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 *
 *  $Id: irq.c,v 1.4.2.9 2004/11/10 22:15:00 joel Exp $
 */
  
#include <rtems/system.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <bsp/VME.h>
#include <bsp/openpic.h>
#include <rtems/score/thread.h>
#include <rtems/score/apiext.h>
#include <libcpu/raw_exception.h>
#include <libcpu/io.h>
#include <bsp/vectors.h>
#include <stdlib.h>

#include <rtems/bspIo.h> /* for printk */
#define RAVEN_INTR_ACK_REG 0xfeff0030

/*
 * pointer to the mask representing the additionnal irq vectors
 * that must be disabled when a particular entry is activated.
 * They will be dynamically computed from the priority table given
 * in BSP_rtems_irq_mngt_set();
 * CAUTION : this table is accessed directly by interrupt routine
 * 	     prologue.
 */
rtems_i8259_masks 	irq_mask_or_tbl[BSP_IRQ_NUMBER];
/*
 * default handler connected on each irq after bsp initialization
 */
static rtems_irq_connect_data	default_rtems_entry;

/*
 * location used to store initial tables used for interrupt
 * management.
 */
static rtems_irq_global_settings* 	internal_config;
static rtems_irq_connect_data*		rtems_hdl_tbl;

/*
 * Check if IRQ is an ISA IRQ
 */
static inline int is_isa_irq(const rtems_irq_symbolic_name irqLine)
{
  return (((int) irqLine <= BSP_ISA_IRQ_MAX_OFFSET) &
	  ((int) irqLine >= BSP_ISA_IRQ_LOWEST_OFFSET)
	 );
}

/*
 * Check if IRQ is an OPENPIC IRQ
 */
static inline int is_pci_irq(const rtems_irq_symbolic_name irqLine)
{
  return (((int) irqLine <= BSP_PCI_IRQ_MAX_OFFSET) &
	  ((int) irqLine >= BSP_PCI_IRQ_LOWEST_OFFSET)
	 );
}

/*
 * Check if IRQ is a Processor IRQ
 */
static inline int is_processor_irq(const rtems_irq_symbolic_name irqLine)
{
  return (((int) irqLine <= BSP_PROCESSOR_IRQ_MAX_OFFSET) &
	  ((int) irqLine >= BSP_PROCESSOR_IRQ_LOWEST_OFFSET)
	 );
}


/*
 * ------------------------ RTEMS Irq helper functions ----------------
 */
 
/*
 * Caution : this function assumes the variable "internal_config"
 * is already set and that the tables it contains are still valid
 * and accessible.
 */
static void compute_i8259_masks_from_prio ()
{
  int i;
  int j;
  /*
   * Always mask at least current interrupt to prevent re-entrance
   */
  for (i=BSP_ISA_IRQ_LOWEST_OFFSET; i < BSP_ISA_IRQ_LOWEST_OFFSET + BSP_ISA_IRQ_NUMBER; i++) {
    * ((unsigned short*) &irq_mask_or_tbl[i]) = (1 << i);
    for (j = BSP_ISA_IRQ_LOWEST_OFFSET; j < BSP_ISA_IRQ_LOWEST_OFFSET + BSP_ISA_IRQ_NUMBER; j++) {
      /*
       * Mask interrupts at i8259 level that have a lower priority
       */
      if (internal_config->irqPrioTbl [i] > internal_config->irqPrioTbl [j]) {
	* ((unsigned short*) &irq_mask_or_tbl[i]) |= (1 << j);
      }
    }
  }
}

/*
 * This function check that the value given for the irq line
 * is valid.
 */

static int isValidInterrupt(int irq)
{
  if ( (irq < BSP_LOWEST_OFFSET) || (irq > BSP_MAX_OFFSET))
    return 0;
  return 1;
}


/*
 * ------------------------ RTEMS Shared Irq Handler Mngt Routines ----------------
 */
int BSP_install_rtems_shared_irq_handler  (const rtems_irq_connect_data* irq)
{
    unsigned int level;
    rtems_irq_connect_data* vchain;
 
    if (!isValidInterrupt(irq->name)) {
      printk("Invalid interrupt vector %d\n",irq->name);
      return 0;
    }

    _CPU_ISR_Disable(level);

    if ( (int)rtems_hdl_tbl[irq->name].next_handler  == -1 ) {
      _CPU_ISR_Enable(level);
      printk("IRQ vector %d already connected to an unshared handler\n",irq->name);
      return 0;
    }

     vchain = (rtems_irq_connect_data*)malloc(sizeof(rtems_irq_connect_data));

    /* save off topmost handler */
    vchain[0]= rtems_hdl_tbl[irq->name];
    
    /*
     * store the data provided by user
     */
    rtems_hdl_tbl[irq->name] = *irq;

    /* link chain to new topmost handler */
    rtems_hdl_tbl[irq->name].next_handler = (void *)vchain;

    
    if (is_isa_irq(irq->name)) {
      /*
       * Enable interrupt at PIC level
       */
      BSP_irq_enable_at_i8259s (irq->name);
    }
    
    if (is_pci_irq(irq->name)) {
      /*
       * Enable interrupt at OPENPIC level
       */
      openpic_enable_irq ((int) irq->name - BSP_PCI_IRQ_LOWEST_OFFSET);
    }

    if (is_processor_irq(irq->name)) {
      /*
       * Enable exception at processor level
       */
    }
    /*
     * Enable interrupt on device
     */
    irq->on(irq);
    
    _CPU_ISR_Enable(level);

    return 1;
}


/*
 * ------------------------ RTEMS Single Irq Handler Mngt Routines ----------------
 */

int BSP_install_rtems_irq_handler  (const rtems_irq_connect_data* irq)
{
    unsigned int level;
 
    if (!isValidInterrupt(irq->name)) {
      printk("Invalid interrupt vector %d\n",irq->name);
      return 0;
    }
    /*
     * Check if default handler is actually connected. If not issue an error.
     * You must first get the current handler via i386_get_current_idt_entry
     * and then disconnect it using i386_delete_idt_entry.
     * RATIONALE : to always have the same transition by forcing the user
     * to get the previous handler before accepting to disconnect.
     */
    _CPU_ISR_Disable(level);
    if (rtems_hdl_tbl[irq->name].hdl != default_rtems_entry.hdl) {
      _CPU_ISR_Enable(level);
      printk("IRQ vector %d already connected\n",irq->name);
      return 0;
    }

    /*
     * store the data provided by user
     */
    rtems_hdl_tbl[irq->name] = *irq;
    rtems_hdl_tbl[irq->name].next_handler = (void *)-1;
    
    if (is_isa_irq(irq->name)) {
      /*
       * Enable interrupt at PIC level
       */
      BSP_irq_enable_at_i8259s (irq->name);
    }
    
    if (is_pci_irq(irq->name)) {
      /*
       * Enable interrupt at OPENPIC level
       */
      openpic_enable_irq ((int) irq->name - BSP_PCI_IRQ_LOWEST_OFFSET);
    }

    if (is_processor_irq(irq->name)) {
      /*
       * Enable exception at processor level
       */
    }
    /*
     * Enable interrupt on device
     */
    irq->on(irq);
    
    _CPU_ISR_Enable(level);

    return 1;
}


int BSP_get_current_rtems_irq_handler	(rtems_irq_connect_data* irq)
{
     unsigned int level;

     if (!isValidInterrupt(irq->name)) {
      return 0;
     }
     _CPU_ISR_Disable(level);
     *irq = rtems_hdl_tbl[irq->name];
     _CPU_ISR_Enable(level);
     return 1;
}

int BSP_remove_rtems_irq_handler  (const rtems_irq_connect_data* irq)
{
   rtems_irq_connect_data *pchain= NULL, *vchain = NULL;
    unsigned int level;
  
    if (!isValidInterrupt(irq->name)) {
      return 0;
    }
    /*
     * Check if default handler is actually connected. If not issue an error.
     * You must first get the current handler via i386_get_current_idt_entry
     * and then disconnect it using i386_delete_idt_entry.
     * RATIONALE : to always have the same transition by forcing the user
     * to get the previous handler before accepting to disconnect.
     */
    _CPU_ISR_Disable(level);
    if (rtems_hdl_tbl[irq->name].hdl != irq->hdl) {
      _CPU_ISR_Enable(level);
      return 0;
    }

    if( (int)rtems_hdl_tbl[irq->name].next_handler != -1 )
    {
       int found = 0;

       for( (pchain= NULL, vchain = &rtems_hdl_tbl[irq->name]);
            (vchain->hdl != default_rtems_entry.hdl);
            (pchain= vchain, vchain = (rtems_irq_connect_data*)vchain->next_handler) )
       {
          if( vchain->hdl == irq->hdl )
          {
             found= -1; break;
          }
       }

       if( !found )
       {
          _CPU_ISR_Enable(level);
          return 0;
       }
    }
    else
    {