sysdeps/unix/sysv/linux/arm/ioperm.c

   1 /* Copyright (C) 1998, 1999, 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Phil Blundell, based on the Alpha version by
   4    David Mosberger.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 /* I/O port access on the ARM is something of a fiction.  What we do is to
  22    map an appropriate area of /dev/mem into user space so that a program
  23    can blast away at the hardware in such a way as to generate I/O cycles
  24    on the bus.  To insulate user code from dependencies on particular
  25    hardware we don't allow calls to inb() and friends to be inlined, but
  26    force them to come through code in here every time.  Performance-critical
  27    registers tend to be memory mapped these days so this should be no big
  28    problem.  */
  29
  30 /* Once upon a time this file used mprotect to enable and disable
  31    access to particular areas of I/O space.  Unfortunately the
  32    mprotect syscall also has the side effect of enabling caching for
  33    the area affected (this is a kernel limitation).  So we now just
  34    enable all the ports all of the time.  */
  35
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <stdio.h>
  39 #include <ctype.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #include <sys/types.h>
  45 #include <sys/mman.h>
  46
  47 #include <asm/page.h>
  48 #include <sys/sysctl.h>
  49
  50 #define PATH_ARM_SYSTYPE        "/etc/arm_systype"
  51 #define PATH_CPUINFO            "/proc/cpuinfo"
  52
  53 #define MAX_PORT        0x10000
  54
  55 static struct {
  56   unsigned long int     base;
  57   unsigned long int     io_base;
  58   unsigned int          shift;
  59   unsigned int          initdone;       /* since all the above could be 0 */
  60 } io;
  61
  62 #define IO_BASE_FOOTBRIDGE      0x7c000000
  63 #define IO_SHIFT_FOOTBRIDGE     0
  64
  65 static struct platform {
  66   const char            *name;
  67   unsigned long int     io_base;
  68   unsigned int          shift;
  69 } platform[] = {
  70   /* All currently supported platforms are in fact the same. :-)  */
  71   {"Chalice-CATS",      IO_BASE_FOOTBRIDGE,     IO_SHIFT_FOOTBRIDGE},
  72   {"DEC-EBSA285",       IO_BASE_FOOTBRIDGE,     IO_SHIFT_FOOTBRIDGE},
  73   {"Corel-NetWinder",   IO_BASE_FOOTBRIDGE,     IO_SHIFT_FOOTBRIDGE},
  74   {"Rebel-NetWinder",   IO_BASE_FOOTBRIDGE,     IO_SHIFT_FOOTBRIDGE},
  75 };
  76
  77 #define IO_ADDR(port)   (io.base + ((port) << io.shift))
  78
  79 /*
  80  * Initialize I/O system.  There are several ways to get the information
  81  * we need.  Each is tried in turn until one succeeds.
  82  *
  83  * 1. Sysctl (CTL_BUS, BUS_ISA, ISA_*).  This is the preferred method
  84  *    but not all kernels support it.
  85  *
  86  * 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
  87  *    - If it matches one of the entries in the table above, use the
  88  *      corresponding values.
  89  *    - If it begins with a number, assume this is a previously
  90  *      unsupported system and the values encode, in order,
  91  *      "<io_base>,<port_shift>".
  92  *
  93  * 3. Lookup the "system type" field in /proc/cpuinfo.  Again, if it
  94  *    matches an entry in the platform[] table, use the corresponding
  95  *    values.
  96  */
  97
  98 static int
  99 init_iosys (void)
 100 {
 101   char systype[256];
 102   int i, n;
 103   static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
 104   static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
 105   size_t len = sizeof(io.base);
 106
 107   if (! sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
 108       && ! sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0))
 109     {
 110       io.initdone = 1;
 111       return 0;
 112     }
 113
 114   n = readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
 115   if (n > 0)
 116     {
 117       systype[n] = '\0';
 118       if (isdigit (systype[0]))
 119         {
 120           if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2)
 121             {
 122               io.initdone = 1;
 123               return 0;
 124             }
 125           /* else we're likely going to fail with the system match below */
 126         }
 127     }
 128   else
 129     {
 130       FILE * fp;
 131
 132       fp = fopen (PATH_CPUINFO, "r");
 133       if (! fp)
 134         return -1;
 135       while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype))
 136              != EOF)
 137         {
 138           if (n == 1)
 139             break;
 140           else
 141             fgets (systype, 256, fp);
 142         }
 143       fclose (fp);
 144
 145       if (n == EOF)
 146         {
 147           /* this can happen if the format of /proc/cpuinfo changes...  */
 148           fprintf (stderr,
 149                    "ioperm: Unable to determine system type.\n"
 150                    "\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
 151           __set_errno (ENODEV);
 152           return -1;
 153         }
 154     }
 155
 156   /* translate systype name into i/o system: */
 157   for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i)
 158     {
 159       if (strcmp (platform[i].name, systype) == 0)
 160         {
 161           io.shift = platform[i].shift;
 162           io.io_base = platform[i].io_base;
 163           io.initdone = 1;
 164           return 0;
 165         }
 166     }
 167
 168   /* systype is not a known platform name... */
 169   __set_errno (ENODEV);
 170   return -1;
 171 }
 172
 173 int
 174 _ioperm (unsigned long int from, unsigned long int num, int turn_on)
 175 {
 176   if (! io.initdone && init_iosys () < 0)
 177     return -1;
 178
 179   /* this test isn't as silly as it may look like; consider overflows! */
 180   if (from >= MAX_PORT || from + num > MAX_PORT)
 181     {
 182       __set_errno (EINVAL);
 183       return -1;
 184     }
 185
 186   if (turn_on)
 187     {
 188       if (! io.base)
 189         {
 190           int fd;
 191
 192           fd = open ("/dev/mem", O_RDWR);
 193           if (fd < 0)
 194             return -1;
 195
 196           io.base =
 197             (unsigned long int) __mmap (0, MAX_PORT << io.shift,
 198                                         PROT_READ | PROT_WRITE,
 199                                         MAP_SHARED, fd, io.io_base);
 200           close (fd);
 201           if ((long) io.base == -1)
 202             return -1;
 203         }
 204     }
 205
 206   return 0;
 207 }
 208
 209
 210 int
 211 _iopl (unsigned int level)
 212 {
 213     if (level > 3)
 214       {
 215         __set_errno (EINVAL);
 216         return -1;
 217       }
 218     if (level)
 219       {
 220         return _ioperm (0, MAX_PORT, 1);
 221       }
 222     return 0;
 223 }
 224
 225
 226 void
 227 _outb (unsigned char b, unsigned long int port)
 228 {
 229   *((volatile unsigned char *)(IO_ADDR (port))) = b;
 230 }
 231
 232
 233 void
 234 _outw (unsigned short b, unsigned long int port)
 235 {
 236   *((volatile unsigned short *)(IO_ADDR (port))) = b;
 237 }
 238
 239
 240 void
 241 _outl (unsigned int b, unsigned long int port)
 242 {
 243   *((volatile unsigned long *)(IO_ADDR (port))) = b;
 244 }
 245
 246
 247 unsigned int
 248 _inb (unsigned long int port)
 249 {
 250   return *((volatile unsigned char *)(IO_ADDR (port)));
 251 }
 252
 253
 254 unsigned int
 255 _inw (unsigned long int port)
 256 {
 257   return *((volatile unsigned short *)(IO_ADDR (port)));
 258 }
 259
 260
 261 unsigned int
 262 _inl (unsigned long int port)
 263 {
 264   return *((volatile unsigned long *)(IO_ADDR (port)));
 265 }
 266
 267 weak_alias (_ioperm, ioperm);
 268 weak_alias (_iopl, iopl);
 269 weak_alias (_inb, inb);
 270 weak_alias (_inw, inw);
 271 weak_alias (_inl, inl);
 272 weak_alias (_outb, outb);
 273 weak_alias (_outw, outw);
 274 weak_alias (_outl, outl);