/* Copyright (C) 1998-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Phil Blundell, based on the Alpha version by

   David Mosberger.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

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

   License along with the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

/* I/O port access on the ARM is something of a fiction.  What we do is to

   map an appropriate area of /dev/mem into user space so that a program

   can blast away at the hardware in such a way as to generate I/O cycles

   on the bus.  To insulate user code from dependencies on particular

   hardware we don't allow calls to inb() and friends to be inlined, but

   force them to come through code in here every time.  Performance-critical

   registers tend to be memory mapped these days so this should be no big

   problem.  */

/* Once upon a time this file used mprotect to enable and disable

   access to particular areas of I/O space.  Unfortunately the

   mprotect syscall also has the side effect of enabling caching for

   the area affected (this is a kernel limitation).  So we now just

   enable all the ports all of the time.  */

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <ctype.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/mman.h>

#include <sys/sysctl.h>

#define MAX_PORT	0x10000

static struct {

  unsigned long int	base;

  unsigned long int	io_base;

  unsigned int		shift;

  unsigned int		initdone;	/* since all the above could be 0 */

} io;

#define IO_ADDR(port)	(io.base + ((port) << io.shift))

/*

 * Initialize I/O system.  The io_bae and port_shift values are fetched

 * using sysctl (CTL_BUS, CTL_BUS_ISA, ISA_*).

 */

static int

init_iosys (void)

{

  static int iobase_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_BASE };

  static int ioshift_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_SHIFT };

  size_t len = sizeof(io.base);

  if (! __sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)

      && ! __sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0))

    {

      io.initdone = 1;

      return 0;

    }

  /* sysctl has failed... */

  __set_errno (ENODEV);

  return -1;

}

int

_ioperm (unsigned long int from, unsigned long int num, int turn_on)

{

  if (! io.initdone && init_iosys () < 0)

    return -1;

  /* this test isn't as silly as it may look like; consider overflows! */

  if (from >= MAX_PORT || from + num > MAX_PORT)

    {

      __set_errno (EINVAL);

      return -1;

    }

  if (turn_on)

    {

      if (! io.base)

	{

	  int fd;

	  fd = __open ("/dev/mem", O_RDWR);

	  if (fd < 0)

	    return -1;

	  io.base =

	    (unsigned long int) __mmap (0, MAX_PORT << io.shift,

					PROT_READ | PROT_WRITE,

					MAP_SHARED, fd, io.io_base);

	  __close (fd);

	  if ((long) io.base == -1)

	    return -1;

	}

    }

  return 0;

}

int

_iopl (unsigned int level)

{

    if (level > 3)

      {

	__set_errno (EINVAL);

	return -1;

      }

    if (level)

      {

	return _ioperm (0, MAX_PORT, 1);

      }

    return 0;

}

void

_outb (unsigned char b, unsigned long int port)

{

  *((volatile unsigned char *)(IO_ADDR (port))) = b;

}

void

_outw (unsigned short b, unsigned long int port)

{

  *((volatile unsigned short *)(IO_ADDR (port))) = b;

}

void

_outl (unsigned int b, unsigned long int port)

{

  *((volatile unsigned long *)(IO_ADDR (port))) = b;

}

unsigned int

_inb (unsigned long int port)

{

  return *((volatile unsigned char *)(IO_ADDR (port)));

}

unsigned int

_inw (unsigned long int port)

{

  return *((volatile unsigned short *)(IO_ADDR (port)));

}

unsigned int

_inl (unsigned long int port)

{

  return *((volatile unsigned long *)(IO_ADDR (port)));

}

weak_alias (_ioperm, ioperm);

weak_alias (_iopl, iopl);

weak_alias (_inb, inb);

weak_alias (_inw, inw);

weak_alias (_inl, inl);

weak_alias (_outb, outb);

weak_alias (_outw, outw);

weak_alias (_outl, outl);