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/*  This file is part of the program psim.

    Copyright (C) 1997,2008, Joel Sherrill <joel@OARcorp.com>

    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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

    */

#ifndef _HW_SEM_C_

#define _HW_SEM_C_

#include "device_table.h"

#ifdef HAVE_STRING_H

#include <string.h>

#else

#ifdef HAVE_STRINGS_H

#include <strings.h>

#endif

#endif

#include <sys/ipc.h>

#include <sys/sem.h>

#include <errno.h>

/* DEVICE

   sem - provide access to a unix semaphore

   DESCRIPTION

   This device implements an interface to a unix semaphore.

   PROPERTIES

   reg = <address> <size> (required)

   Determine where the memory lives in the parents address space.

   key = <integer> (required)

   This is the key of the unix semaphore.

   EXAMPLES

   Enable tracing of the sem:

   |  bash$ psim -t sem-device \

   Configure a UNIX semaphore using key 0x12345678 mapped into psim

   address space at 0xfff00000:

   |  -o '/sem@0xfff00000/reg 0xfff00000 0x80000' \

   |  -o '/sem@0xfff00000/key 0x12345678' \

   sim/ppc/run -o '/#address-cells 1' \

         -o '/sem@0xfff00000/reg 0xfff00000 12' \

         -o '/sem@0xfff00000/key 0x12345678' ../psim-hello/hello

   REGISTERS

   offset 0 - lock count

   offset 4 - lock operation

   offset 8 - unlock operation

   All reads return the current or resulting count.

   BUGS

   None known.

   */

typedef struct _hw_sem_device {

  unsigned_word physical_address;

  key_t key;

  int id;

  int initial;

  int count;

} hw_sem_device;

#ifndef HAVE_UNION_SEMUN

union semun {

  int val;

  struct semid_ds *buf;

  unsigned short int *array;

#if defined(__linux__)

  struct seminfo *__buf;

#endif

};

#endif

static void

hw_sem_init_data(device *me)

{

  hw_sem_device *sem = (hw_sem_device*)device_data(me);

  const device_unit *d;

  int status;

  union semun help;

  /* initialize the properties of the sem */

  if (device_find_property(me, "key") == NULL)

    error("sem_init_data() required key property is missing\n");

  if (device_find_property(me, "value") == NULL)

    error("sem_init_data() required value property is missing\n");

  sem->key = (key_t) device_find_integer_property(me, "key");

  DTRACE(sem, ("semaphore key (%d)\n", sem->key) );

  sem->initial = (int) device_find_integer_property(me, "value");

  DTRACE(sem, ("semaphore initial value (%d)\n", sem->initial) );

  d = device_unit_address(me);

  sem->physical_address = d->cells[ d->nr_cells-1 ];

  DTRACE(sem, ("semaphore physical_address=0x%x\n", sem->physical_address));

  /* Now to initialize the semaphore */

  if ( sem->initial != -1 ) {

    sem->id = semget(sem->key, 1, IPC_CREAT | 0660);

    if (sem->id == -1)

      error("hw_sem_init_data() semget failed\n");

    help.val = sem->initial;

    status = semctl( sem->id, 0, SETVAL, help );

    if (status == -1)

      error("hw_sem_init_data() semctl -- set value failed\n");

  } else {

    sem->id = semget(sem->key, 1, 0660);

    if (sem->id == -1)

      error("hw_sem_init_data() semget failed\n");

  }

  sem->count = semctl( sem->id, 0, GETVAL, help );

  if (sem->count == -1)

    error("hw_sem_init_data() semctl -- get value failed\n");

  DTRACE(sem, ("semaphore OS value (%d)\n", sem->count) );

}

static void

hw_sem_attach_address_callback(device *me,

                                attach_type attach,

                                int space,

                                unsigned_word addr,

                                unsigned nr_bytes,

                                access_type access,

                                device *client) /*callback/default*/

{

  hw_sem_device *sem = (hw_sem_device*)device_data(me);

  if (space != 0)

    error("sem_attach_address_callback() invalid address space\n");

  if (nr_bytes == 12)

    error("sem_attach_address_callback() invalid size\n");

  sem->physical_address = addr;

  DTRACE(sem, ("semaphore physical_address=0x%x\n", addr));

}

static unsigned

hw_sem_io_read_buffer(device *me,

                         void *dest,

                         int space,

                         unsigned_word addr,

                         unsigned nr_bytes,

                         cpu *processor,

                         unsigned_word cia)

{

  hw_sem_device *sem = (hw_sem_device*)device_data(me);

  struct sembuf sb;

  int status;

  unsigned32 u32;

  union semun help;

  /* do we need to worry about out of range addresses? */

  DTRACE(sem, ("semaphore read addr=0x%x length=%d\n", addr, nr_bytes));

  if (!(addr >= sem->physical_address && addr <= sem->physical_address + 11))

    error("hw_sem_io_read_buffer() invalid address - out of range\n");

  if ((addr % 4) != 0)

    error("hw_sem_io_read_buffer() invalid address - alignment\n");

  if (nr_bytes != 4)

    error("hw_sem_io_read_buffer() invalid length\n");

  switch ( (addr - sem->physical_address) / 4 ) {

    case 0:  /* OBTAIN CURRENT VALUE */

      break;

    case 1:  /* LOCK */

      sb.sem_num = 0;

      sb.sem_op  = -1;

      sb.sem_flg = 0;

      status = semop(sem->id, &sb, 1);

      if (status == -1) {

        perror( "hw_sem.c: lock" );

        error("hw_sem_io_read_buffer() sem lock\n");

      }

      DTRACE(sem, ("semaphore lock %d\n", sem->count));

      break;

    case 2: /* UNLOCK */

      sb.sem_num = 0;

      sb.sem_op  = 1;

      sb.sem_flg = 0;

      status = semop(sem->id, &sb, 1);

      if (status == -1) {

        perror( "hw_sem.c: unlock" );

        error("hw_sem_io_read_buffer() sem unlock\n");

      }

      DTRACE(sem, ("semaphore unlock %d\n", sem->count));

      break;

    default:

      error("hw_sem_io_read_buffer() invalid address - unknown error\n");

      break;

  }

  /* assume target is big endian */

  u32 = H2T_4(semctl( sem->id, 0, GETVAL, help ));

  DTRACE(sem, ("semaphore OS value (%d)\n", u32) );

  if (u32 == 0xffffffff) {

    perror( "hw_sem.c: getval" );

    error("hw_sem_io_read_buffer() semctl -- get value failed\n");

  }

  memcpy(dest, &u32, nr_bytes);

  return nr_bytes;

}

static device_callbacks const hw_sem_callbacks = {

  { generic_device_init_address, hw_sem_init_data },

  { hw_sem_attach_address_callback, }, /* address */

  { hw_sem_io_read_buffer, NULL }, /* IO */

  { NULL, }, /* DMA */

  { NULL, }, /* interrupt */

  { NULL, }, /* unit */

  NULL,

};

static void *

hw_sem_create(const char *name,

                 const device_unit *unit_address,

                 const char *args)

{

  hw_sem_device *sem = ZALLOC(hw_sem_device);

  return sem;

}

const device_descriptor hw_sem_device_descriptor[] = {

  { "sem", hw_sem_create, &hw_sem_callbacks },

  { NULL },

};

#endif /* _HW_SEM_C_ */