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/* gpio.h -- GPIO code simulation

   Copyright (C) 2001 Erez Volk, erez@mailandnews.comopencores.org

   This file is part of OpenRISC 1000 Architectural Simulator.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include "gpio.h"

#include "gpio_i.h"

#include "sim-config.h"

#include "pic.h"

#include "vapi.h"

static struct gpio_device gpios[MAX_GPIOS];

static void gpio_vapi_read( unsigned long id, unsigned long data );

static unsigned long gpio_read32( unsigned long addr );

static void gpio_write32( unsigned long addr, unsigned long value );

static void gpio_external_clock( unsigned long value );

static void gpio_device_clock( struct gpio_device *gpio );

static int gpio_find_device( unsigned long addr, struct gpio_device **gpio, unsigned long *reladdr );

static struct gpio_device *gpio_find_vapi_device( unsigned long id, unsigned *which_vapi );

/* Initialize all parameters and state */

void gpio_reset( void )

{

  static int first_time = 1;

  unsigned i, j;

  if ( first_time ) {

    memset( gpios, 0, sizeof(gpios) );

    first_time = 0;

  }

  for ( i = 0; i < config.ngpios; ++ i ) {

    struct gpio_device *gpio = &(gpios[i]);

    gpio->gpio_number = i;

    gpio->baseaddr = config.gpios[i].baseaddr;

    if ( gpio->baseaddr != 0 ) {

      /* Get IRQ */

      gpio->irq = config.gpios[i].irq;

      /* Register memory range */

      register_memoryarea( gpio->baseaddr, GPIO_ADDR_SPACE, 4, 0, gpio_read32, gpio_write32 );

      /* Possibly connect to VAPI */

      if ( config.gpios[i].base_vapi_id ) {

        gpio->base_vapi_id = config.gpios[i].base_vapi_id;

        vapi_install_multi_handler( gpio->base_vapi_id, GPIO_NUM_VAPI_IDS, gpio_vapi_read );

      }

    }

  }

}

/* Dump status */

void gpio_status( void )

{

  unsigned i;

  for ( i = 0; i < config.ngpios; ++ i ) {

    struct gpio_device *gpio = &(gpios[i]);

    if ( gpio->baseaddr == 0 )

      continue;

    PRINTF( "\nGPIO %u at 0x%08X:\n", i, gpio->baseaddr );

    PRINTF( "RGPIO_IN     : 0x%08lX\n", gpio->curr.in );

    PRINTF( "RGPIO_OUT    : 0x%08lX\n", gpio->curr.out );

    PRINTF( "RGPIO_OE     : 0x%08lX\n", gpio->curr.oe );

    PRINTF( "RGPIO_INTE   : 0x%08lX\n", gpio->curr.inte );

    PRINTF( "RGPIO_PTRIG  : 0x%08lX\n", gpio->curr.ptrig );

    PRINTF( "RGPIO_AUX    : 0x%08lX\n", gpio->curr.aux );

    PRINTF( "RGPIO_CTRL   : 0x%08lX\n", gpio->curr.ctrl );

    PRINTF( "RGPIO_INTS   : 0x%08lX\n", gpio->curr.ints );

  }

}

/* Convert a memory address to a device struct and relative address.

 * Return nonzero on success */

int gpio_find_device( unsigned long addr, struct gpio_device **gpio, unsigned long *reladdr )

{

  unsigned i;

  *gpio = NULL;

  for ( i = 0; i < config.ngpios && *gpio == NULL; ++ i ) {

    if ( (addr >= gpios[i].baseaddr) && (addr < gpios[i].baseaddr + GPIO_ADDR_SPACE) )

      *gpio = &(gpios[i]);

  }

  /* verify we found a device */

  if ( *gpio == NULL )

    return 0;

  /* Verify legal address */

  if ( (addr - (*gpio)->baseaddr) % 4 != 0 )

    return 0;

  *reladdr = addr - (*gpio)->baseaddr;

  return 1;

}

/* Find device by vapi id */

struct gpio_device *gpio_find_vapi_device( unsigned long id, unsigned *which )

{

  unsigned i, j;

  for ( i = 0; i < config.ngpios; ++ i )

    if ( (id >= gpios[i].base_vapi_id) && (id < gpios[i].base_vapi_id + GPIO_NUM_VAPI_IDS) ) {

      *which = id - gpios[i].base_vapi_id;

      return &(gpios[i]);

    }

  return NULL;

}

/* Wishbone read */

unsigned long gpio_read32( unsigned long addr )

{

  struct gpio_device *gpio;

  if ( !gpio_find_device( addr, &gpio, &addr ) )        {

    debug( 2, "gpio_read32( 0x%08lX ): Not in registered range(s)\n", addr );

    return 0;

  }

  switch( addr ) {

  case RGPIO_IN: return gpio->curr.in | gpio->curr.out;

  case RGPIO_OUT: return gpio->curr.out;

  case RGPIO_OE: return gpio->curr.oe;

  case RGPIO_INTE: return gpio->curr.inte;

  case RGPIO_PTRIG: return gpio->curr.ptrig;

  case RGPIO_AUX: return gpio->curr.aux;

  case RGPIO_CTRL: return gpio->curr.ctrl;

  case RGPIO_INTS: return gpio->curr.ints;

  }

}

/* Wishbone write */

void gpio_write32( unsigned long addr, unsigned long value )

{

  struct gpio_device *gpio;

  if ( !gpio_find_device( addr, &gpio, &addr ) )        {

    debug( 2, "gpio_write32( 0x%08lX ): Not in registered range(s)\n", addr );

    return;

  }

  switch( addr ) {

  case RGPIO_IN: debug( 5, "GPIO: Cannot write to RGPIO_IN\n" ); break;

  case RGPIO_OUT: gpio->next.out = value; break;

  case RGPIO_OE: gpio->next.oe = value; break;

  case RGPIO_INTE: gpio->next.inte = value; break;

  case RGPIO_PTRIG: gpio->next.ptrig = value; break;

  case RGPIO_AUX: gpio->next.aux = value; break;

  case RGPIO_CTRL: gpio->next.ctrl = value; break;

  case RGPIO_INTS: gpio->next.ints = value; break;

  }

}

/* Input from "outside world" */

void gpio_vapi_read( unsigned long id, unsigned long data )

{

  unsigned which;

  struct gpio_device *gpio = gpio_find_vapi_device( id, &which );

  debug( 5, "GPIO: id %08x, data %08x\n", id, data );

  if ( !gpio ) {

    debug( 1, "GPIO: VAPI ID %08x is not ours!\n", id );

    return;

  }

  switch( which ) {

  case GPIO_VAPI_DATA:

    debug( 4, "GPIO: Next input from VAPI = 0x%08x (RGPIO_OE = 0x%08x)\n", data, gpio->next.oe );

    gpio->next.in = data;

    break;

  case GPIO_VAPI_AUX:

    gpio->auxiliary_inputs = data;

    break;

  case GPIO_VAPI_RGPIO_OE:

    gpio->next.oe = data;

    break;

  case GPIO_VAPI_RGPIO_INTE:

    gpio->next.inte = data;

    break;

  case GPIO_VAPI_RGPIO_PTRIG:

    gpio->next.ptrig = data;

    break;

  case GPIO_VAPI_RGPIO_AUX:

    gpio->next.aux = data;

    break;

  case GPIO_VAPI_RGPIO_CTRL:

    gpio->next.ctrl = data;

    break;

  case GPIO_VAPI_CLOCK:

    gpio_external_clock( data );

    break;

  }

}

/* System Clock. */

void gpio_clock( void )

{

  unsigned i;

  for ( i = 0; i < config.ngpios; ++ i )

    if ( !(gpios[i].curr.ctrl & RGPIO_CTRL_ECLK) )

      gpio_device_clock( &(gpios[i]) );

}

/* External Clock. */

void gpio_external_clock( unsigned long value )

{

  unsigned i;

  /* "Normalize" clock value */

  value = (value != 0);

  for ( i = 0; i < config.ngpios; ++ i ) {

    struct gpio_device *gpio = &(gpios[i]);

    int use_external_clock = ((gpio->curr.ctrl & RGPIO_CTRL_ECLK) == RGPIO_CTRL_ECLK);

    int negative_edge = ((gpio->curr.ctrl & RGPIO_CTRL_NEC) == RGPIO_CTRL_NEC);

    gpio->next.external_clock = value;

    if ( use_external_clock && (gpio->next.external_clock != gpio->curr.external_clock) && (value != negative_edge) )

      gpio_device_clock( gpio );

  }

}

/* Clock as handld by one device. */

void gpio_device_clock( struct gpio_device *gpio )

{

  /* Calculate new inputs and outputs */

  gpio->next.in &= ~gpio->next.oe; /* Only input bits */

  /* Replace requested output bits with aux input */

  gpio->next.out = (gpio->next.out & ~gpio->next.aux) | (gpio->auxiliary_inputs & gpio->next.aux);

  gpio->next.out &= gpio->next.oe; /* Only output-enabled bits */

  /* If any outputs changed, notify the world (i.e. vapi) */

  if ( gpio->next.out != gpio->curr.out ) {

    debug( 4, "GPIO: New output 0x%08x, RGPIO_OE = 0x%08x\n", gpio->next.out, gpio->next.oe );

    if ( gpio->base_vapi_id )

      vapi_send( gpio->base_vapi_id + GPIO_VAPI_DATA, gpio->next.out );

  }

  /* If any inputs changed and interrupt enabled, generate interrupt */

  if ( gpio->next.in != gpio->curr.in ) {

    debug( 4, "GPIO: New input 0x%08x\n", gpio->next.in );

    if ( gpio->next.ctrl & RGPIO_CTRL_INTE ) {

      unsigned changed_bits = gpio->next.in ^ gpio->curr.in; /* inputs that have changed */

      unsigned set_bits = changed_bits & gpio->next.in; /* inputs that have been set */

      unsigned cleared_bits = changed_bits & gpio->curr.in; /* inputs that have been cleared */

      unsigned relevant_bits = (gpio->next.ptrig & set_bits) | (~gpio->next.ptrig & cleared_bits);

      if ( relevant_bits & gpio->next.inte ) {

        debug( 3, "GPIO: Reporting interrupt %d\n", gpio->irq );

        report_interrupt( gpio->irq );

        gpio->next.ctrl |= RGPIO_CTRL_INTS;

        gpio->next.ints |= relevant_bits & gpio->next.inte;

      }

    }

  }

  /* Switch to values for next clock */

  memcpy( &(gpio->curr), &(gpio->next), sizeof(gpio->curr) );

}