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/* irq.c

 *

 *  This file contains the implementation of the function described in irq.h

 *

 *  CopyRight (C) 1998 valette@crf.canon.fr

 *

 *  The license and distribution terms for this file may be

 *  found in found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: irq.c,v 1.2 2001-09-27 11:59:49 chris Exp $

 */

#include <bsp.h>

#include <irq.h>

#include <rtems/score/thread.h>

#include <rtems/score/apiext.h>

/*

 * 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 teh prioruty 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_LINES_NUMBER];

/*

 * Copy of data given via initial BSP_rtems_irq_mngt_set() for

 * the sake of efficiency.

 * CAUTION : this table is accessed directly by interrupt routine

 *           prologue.

 */

rtems_irq_hdl           current_irq[BSP_IRQ_LINES_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;

/*-------------------------------------------------------------------------+

| Cache for 1st and 2nd PIC IRQ line's status (enabled or disabled) register.

+--------------------------------------------------------------------------*/

/*

 * lower byte is interrupt mask on the master PIC.

 * while upper bits are interrupt on the slave PIC.

 * This cache is initialized in ldseg.s

 */

rtems_i8259_masks i8259s_cache = 0xFFFB;

/*-------------------------------------------------------------------------+

|         Function:  BSP_irq_disable_at_i8259s

|      Description: Mask IRQ line in appropriate PIC chip.

| Global Variables: i8259s_cache

|        Arguments: vector_offset - number of IRQ line to mask.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

int BSP_irq_disable_at_i8259s    (const rtems_irq_symbolic_name irqLine)

{

  unsigned short mask;

  unsigned int  level;

  if ( ((int)irqLine < BSP_LOWEST_OFFSET) ||

       ((int)irqLine > BSP_MAX_OFFSET )

       )

    return 1;

  _CPU_ISR_Disable(level);

  mask = 1 << irqLine;

  i8259s_cache |= mask;

  if (irqLine < 8)

  {

    outport_byte(PIC_MASTER_IMR_IO_PORT, i8259s_cache & 0xff);

  }

  else

  {

    outport_byte(PIC_SLAVE_IMR_IO_PORT, ((i8259s_cache & 0xff00) >> 8));

  }

  _CPU_ISR_Enable (level);

  return 0;

}

/*-------------------------------------------------------------------------+

|         Function:  BSP_irq_enable_at_i8259s

|      Description: Unmask IRQ line in appropriate PIC chip.

| Global Variables: i8259s_cache

|        Arguments: irqLine - number of IRQ line to mask.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

int BSP_irq_enable_at_i8259s    (const rtems_irq_symbolic_name irqLine)

{

  unsigned short mask;

  unsigned int  level;

  if ( ((int)irqLine < BSP_LOWEST_OFFSET) ||

       ((int)irqLine > BSP_MAX_OFFSET )

       )

    return 1;

  _CPU_ISR_Disable(level);

  mask = ~(1 << irqLine);

  i8259s_cache &= mask;

  if (irqLine < 8)

  {

    outport_byte(PIC_MASTER_IMR_IO_PORT, i8259s_cache & 0xff);

  }

  else

  {

    outport_byte(PIC_SLAVE_IMR_IO_PORT, ((i8259s_cache & 0xff00) >> 8));

  }

  _CPU_ISR_Enable (level);

  return 0;

} /* mask_irq */

int BSP_irq_enabled_at_i8259s           (const rtems_irq_symbolic_name irqLine)

{

  unsigned short mask;

  if ( ((int)irqLine < BSP_LOWEST_OFFSET) ||

       ((int)irqLine > BSP_MAX_OFFSET )

     )

    return 1;

  mask = (1 << irqLine);

  return  (~(i8259s_cache & mask));

}

/*-------------------------------------------------------------------------+

|         Function: BSP_irq_ack_at_i8259s

|      Description: Signal generic End Of Interrupt (EOI) to appropriate PIC.

| Global Variables: None.

|        Arguments: irqLine - number of IRQ line to acknowledge.

|          Returns: Nothing.

+--------------------------------------------------------------------------*/

int BSP_irq_ack_at_i8259s       (const rtems_irq_symbolic_name irqLine)

{

  if ( ((int)irqLine < BSP_LOWEST_OFFSET) ||

       ((int)irqLine > BSP_MAX_OFFSET )

       )

    return 1;

  if (irqLine >= 8) {

   outport_byte(PIC_SLAVE_COMMAND_IO_PORT, PIC_EOI);

  }

  outport_byte(PIC_MASTER_COMMAND_IO_PORT, PIC_EOI);

  return 0;

} /* ackIRQ */

/*

 * ------------------------ 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 ()

{

  unsigned int i;

  unsigned int j;

  /*

   * Always mask at least current interrupt to prevent re-entrance

   */

  for (i=0; i < internal_config->irqNb; i++) {

    * ((unsigned short*) &irq_mask_or_tbl[i]) = (1 << i);

    for (j = 0; j < internal_config->irqNb; 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);

      }

    }

  }

}

/*

 * Caution : this function assumes the variable "internal_config"

 * is already set and that the tables it contains are still valid

 * and accessible.

 */

static void make_copy_of_handlers ()

{

  int i;

  for (i=0; i < internal_config->irqNb; i++) {

    current_irq [i] = internal_config->irqHdlTbl[i].hdl;

  }

}

/*

 * 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 Single Irq Handler Mngt Routines ----------------

 */

int BSP_install_rtems_irq_handler  (const rtems_irq_connect_data* irq)

{

    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.

     */

    if (rtems_hdl_tbl[irq->name].hdl != default_rtems_entry.hdl) {

      return 0;

    }

    _CPU_ISR_Disable(level);

    /*

     * store the data provided by user

     */

    rtems_hdl_tbl[irq->name] = *irq;

    /*

     * update table used directly by rtems interrupt prologue

     */

    current_irq [irq->name] = irq->hdl;

    /*

     * Enable interrupt at PIC level

     */

    BSP_irq_enable_at_i8259s (irq->name);

    /*

     * 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)

{

     if (!isValidInterrupt(irq->name)) {

      return 0;

     }

     *irq = rtems_hdl_tbl[irq->name];

     return 1;

}

int BSP_remove_rtems_irq_handler  (const rtems_irq_connect_data* irq)

{

    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.

     */

    if (rtems_hdl_tbl[irq->name].hdl != irq->hdl) {

      return 0;

    }

    _CPU_ISR_Disable(level);

    /*

     * disable interrupt at PIC level

     */

    BSP_irq_disable_at_i8259s (irq->name);

    /*

     * Disable interrupt on device

     */

    irq->off(irq);

    /*

     * restore the default irq value

     */

    rtems_hdl_tbl[irq->name] = default_rtems_entry;

    current_irq[irq->name] = default_rtems_entry.hdl;

    _CPU_ISR_Enable(level);

    return 1;

}

/*

 * ------------------------ RTEMS Global Irq Handler Mngt Routines ----------------

 */

int BSP_rtems_irq_mngt_set(rtems_irq_global_settings* config)

{

    int i;

    unsigned int level;

   /*

    * Store various code accelerators

    */

    internal_config             = config;

    default_rtems_entry         = config->defaultEntry;

    rtems_hdl_tbl               = config->irqHdlTbl;

    _CPU_ISR_Disable(level);

    /*

     * set up internal tables used by rtems interrupt prologue

     */

    compute_i8259_masks_from_prio ();

    make_copy_of_handlers ();

    for (i=0; i < internal_config->irqNb; i++) {

      if (rtems_hdl_tbl[i].hdl != default_rtems_entry.hdl) {

        BSP_irq_enable_at_i8259s (i);

        rtems_hdl_tbl[i].on(&rtems_hdl_tbl[i]);

      }

      else {

        rtems_hdl_tbl[i].off(&rtems_hdl_tbl[i]);

        BSP_irq_disable_at_i8259s (i);

      }

    }

    /*

     * must enable slave pic anyway

     */

    BSP_irq_enable_at_i8259s (2);

    _CPU_ISR_Enable(level);

    return 1;

}

int BSP_rtems_irq_mngt_get(rtems_irq_global_settings** config)

{

    *config = internal_config;

    return 0;

}

void _ThreadProcessSignalsFromIrq (CPU_Exception_frame* ctx)

{

  /*

   * Process pending signals that have not already been

   * processed by _Thread_Displatch. This happens quite

   * unfrequently : the ISR must have posted an action

   * to the current running thread.

   */

  if ( _Thread_Do_post_task_switch_extension ||

       _Thread_Executing->do_post_task_switch_extension ) {

    _Thread_Executing->do_post_task_switch_extension = FALSE;

    _API_extensions_Run_postswitch();

  }

  /*

   * I plan to process other thread related events here.

   * This will include DEBUG session requested from keyboard...

   */

}