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/* Copyright (C) 1998, 1999 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* 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 <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <asm/page.h>
#include <sys/sysctl.h>
#include <linux/version.h>
#define PATH_ARM_SYSTYPE "/etc/arm_systype"
#define PATH_CPUINFO "/proc/cpuinfo"
#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_BASE_FOOTBRIDGE 0x7c000000
#define IO_SHIFT_FOOTBRIDGE 0
static struct platform {
const char *name;
unsigned long int io_base;
unsigned int shift;
} platform[] = {
/* All currently supported platforms are in fact the same. :-) */
{"Chalice-CATS", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
{"DEC-EBSA285", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
{"Corel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
{"Rebel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
};
#define IO_ADDR(port) (io.base + ((port) << io.shift))
/*
* Initialize I/O system. There are several ways to get the information
* we need. Each is tried in turn until one succeeds.
*
* 1. Sysctl (CTL_BUS, BUS_ISA, ISA_*). This is the preferred method
* but not all kernels support it.
*
* 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
* - If it matches one of the entries in the table above, use the
* corresponding values.
* - If it begins with a number, assume this is a previously
* unsupported system and the values encode, in order,
* "<io_base>,<port_shift>".
*
* 3. Lookup the "system type" field in /proc/cpuinfo. Again, if it
* matches an entry in the platform[] table, use the corresponding
* values.
*
* 4. BUS_ISA is changed to CTL_BUS_ISA (for kernel since 2.4.23).
*/
static int
init_iosys (void)
{
char systype[256];
int i, n;
#if LINUX_VERSION_CODE < 132119
static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
#else
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 };
#endif
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;
}
n = readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
if (n > 0) {
systype[n] = '\0';
if (isdigit (systype[0])) {
if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2) {
io.initdone = 1;
return 0;
}
/* else we're likely going to fail with the system match below */
}
}
else {
FILE * fp;
fp = fopen (PATH_CPUINFO, "r");
if (! fp)
return -1;
while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype)) != EOF) {
if (n == 1)
break;
else
fgets (systype, 256, fp);
}
fclose (fp);
if (n == EOF) {
/* this can happen if the format of /proc/cpuinfo changes... */
fprintf (stderr, "ioperm: Unable to determine system type.\n"
"\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
__set_errno (ENODEV);
return -1;
}
}
/* translate systype name into i/o system: */
for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i) {
if (strcmp (platform[i].name, systype) == 0) {
io.shift = platform[i].shift;
io.io_base = platform[i].io_base;
io.initdone = 1;
return 0;
}
}
/* systype is not a known platform name... */
__set_errno (EINVAL);
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;
}
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)));
}
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