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glibc/sysdeps/unix/sysv/linux/arm/ioperm.c
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/* Copyright (C) 1998-2015 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); |