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280 lines
7.0 KiB
C
280 lines
7.0 KiB
C
/* Copyright (C) 1998-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Phil Blundell, based on the Alpha version by
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David Mosberger.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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/* I/O port access on the ARM is something of a fiction. What we do is to
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map an appropriate area of /dev/mem into user space so that a program
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can blast away at the hardware in such a way as to generate I/O cycles
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on the bus. To insulate user code from dependencies on particular
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hardware we don't allow calls to inb() and friends to be inlined, but
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force them to come through code in here every time. Performance-critical
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registers tend to be memory mapped these days so this should be no big
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problem. */
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/* Once upon a time this file used mprotect to enable and disable
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access to particular areas of I/O space. Unfortunately the
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mprotect syscall also has the side effect of enabling caching for
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the area affected (this is a kernel limitation). So we now just
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enable all the ports all of the time. */
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <linux/version.h>
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#include <sys/sysctl.h>
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#define PATH_ARM_SYSTYPE "/etc/arm_systype"
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#define PATH_CPUINFO "/proc/cpuinfo"
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#define MAX_PORT 0x10000
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static struct {
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unsigned long int base;
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unsigned long int io_base;
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unsigned int shift;
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unsigned int initdone; /* since all the above could be 0 */
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} io;
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#define IO_BASE_FOOTBRIDGE 0x7c000000
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#define IO_SHIFT_FOOTBRIDGE 0
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static struct platform {
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const char *name;
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unsigned long int io_base;
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unsigned int shift;
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} platform[] = {
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/* All currently supported platforms are in fact the same. :-) */
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{"Chalice-CATS", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
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{"DEC-EBSA285", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
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{"Corel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
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{"Rebel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
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};
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#define IO_ADDR(port) (io.base + ((port) << io.shift))
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/*
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* Initialize I/O system. There are several ways to get the information
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* we need. Each is tried in turn until one succeeds.
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*
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* 1. Sysctl (CTL_BUS, CTL_BUS_ISA, ISA_*). This is the preferred method
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* but not all kernels support it.
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*
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* 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
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* - If it matches one of the entries in the table above, use the
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* corresponding values.
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* - If it begins with a number, assume this is a previously
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* unsupported system and the values encode, in order,
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* "<io_base>,<port_shift>".
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*
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* 3. Lookup the "system type" field in /proc/cpuinfo. Again, if it
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* matches an entry in the platform[] table, use the corresponding
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* values.
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*/
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/* The Linux kernel headers renamed this constant between 2.5.26 and
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2.5.27. It was backported to 2.4 between 2.4.22 and 2.4.23. */
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,23)
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# define BUS_ISA CTL_BUS_ISA
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#endif
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static int
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init_iosys (void)
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{
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char systype[256];
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int i, n;
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static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
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static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
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size_t len = sizeof(io.base);
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if (! __sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
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&& ! __sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0))
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{
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io.initdone = 1;
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return 0;
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}
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n = __readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
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if (n > 0)
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{
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systype[n] = '\0';
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if (isdigit (systype[0]))
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{
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if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2)
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{
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io.initdone = 1;
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return 0;
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}
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/* else we're likely going to fail with the system match below */
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}
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}
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else
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{
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FILE * fp;
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fp = fopen (PATH_CPUINFO, "rce");
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if (! fp)
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return -1;
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while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype))
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!= EOF)
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{
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if (n == 1)
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break;
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else
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fgets_unlocked (systype, 256, fp);
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}
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fclose (fp);
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if (n == EOF)
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{
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/* this can happen if the format of /proc/cpuinfo changes... */
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fprintf (stderr,
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"ioperm: Unable to determine system type.\n"
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"\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
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__set_errno (ENODEV);
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return -1;
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}
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}
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/* translate systype name into i/o system: */
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for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i)
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{
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if (strcmp (platform[i].name, systype) == 0)
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{
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io.shift = platform[i].shift;
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io.io_base = platform[i].io_base;
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io.initdone = 1;
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return 0;
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}
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}
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/* systype is not a known platform name... */
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__set_errno (ENODEV);
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return -1;
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}
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int
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_ioperm (unsigned long int from, unsigned long int num, int turn_on)
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{
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if (! io.initdone && init_iosys () < 0)
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return -1;
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/* this test isn't as silly as it may look like; consider overflows! */
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if (from >= MAX_PORT || from + num > MAX_PORT)
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{
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__set_errno (EINVAL);
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return -1;
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}
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if (turn_on)
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{
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if (! io.base)
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{
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int fd;
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fd = __open ("/dev/mem", O_RDWR);
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if (fd < 0)
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return -1;
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io.base =
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(unsigned long int) __mmap (0, MAX_PORT << io.shift,
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PROT_READ | PROT_WRITE,
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MAP_SHARED, fd, io.io_base);
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__close (fd);
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if ((long) io.base == -1)
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return -1;
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}
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}
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return 0;
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}
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int
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_iopl (unsigned int level)
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{
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if (level > 3)
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{
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__set_errno (EINVAL);
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return -1;
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}
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if (level)
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{
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return _ioperm (0, MAX_PORT, 1);
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}
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return 0;
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}
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void
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_outb (unsigned char b, unsigned long int port)
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{
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*((volatile unsigned char *)(IO_ADDR (port))) = b;
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}
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void
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_outw (unsigned short b, unsigned long int port)
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{
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*((volatile unsigned short *)(IO_ADDR (port))) = b;
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}
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void
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_outl (unsigned int b, unsigned long int port)
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{
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*((volatile unsigned long *)(IO_ADDR (port))) = b;
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}
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unsigned int
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_inb (unsigned long int port)
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{
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return *((volatile unsigned char *)(IO_ADDR (port)));
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}
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unsigned int
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_inw (unsigned long int port)
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{
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return *((volatile unsigned short *)(IO_ADDR (port)));
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}
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unsigned int
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_inl (unsigned long int port)
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{
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return *((volatile unsigned long *)(IO_ADDR (port)));
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}
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weak_alias (_ioperm, ioperm);
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weak_alias (_iopl, iopl);
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weak_alias (_inb, inb);
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weak_alias (_inw, inw);
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weak_alias (_inl, inl);
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weak_alias (_outb, outb);
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weak_alias (_outw, outw);
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weak_alias (_outl, outl);
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