sysdeps/unix/sysv/linux/sparc/sparc64/get_clockfreq.c

   1 /* Get frequency of the system processor.  sparc64 version.
   2    Copyright (C) 2001, 2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  20 #include <fcntl.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <dirent.h>
  24 #include <stdlib.h>
  25 #include <sys/ioctl.h>
  26 #include <libc-internal.h>
  27 #include <asm/openpromio.h>
  28
  29 static hp_timing_t
  30 __get_clockfreq_via_cpuinfo (void)
  31 {
  32   hp_timing_t result;
  33   int fd;
  34
  35   result = 0;
  36
  37   fd = __open ("/proc/cpuinfo", O_RDONLY);
  38   if (fd != -1)
  39     {
  40       char buf[8192];
  41       ssize_t n;
  42
  43       n = __read (fd, buf, sizeof buf);
  44       if (n > 0)
  45         {
  46           char *mhz = memmem (buf, n, "Cpu0ClkTck", 7);
  47
  48           if (mhz != NULL)
  49             {
  50               char *endp = buf + n;
  51
  52               /* Search for the beginning of the string.  */
  53               while (mhz < endp
  54                      && (*mhz < '0' || *mhz > '9')
  55                      && (*mhz < 'a' || *mhz > 'f')
  56                      && *mhz != '\n')
  57                 ++mhz;
  58
  59               while (mhz < endp && *mhz != '\n')
  60                 {
  61                   if ((*mhz >= '0' && *mhz <= '9') ||
  62                       (*mhz >= 'a' && *mhz <= 'f'))
  63                     {
  64                       result <<= 4;
  65                       if (*mhz >= '0' && *mhz <= '9')
  66                         result += *mhz - '0';
  67                       else
  68                         result += (*mhz - 'a') + 10;
  69                     }
  70                   ++mhz;
  71                 }
  72             }
  73         }
  74
  75       __close (fd);
  76     }
  77
  78   return result;
  79 }
  80
  81 static hp_timing_t
  82 __get_clockfreq_via_proc_openprom (void)
  83 {
  84   hp_timing_t result;
  85   int obp_fd;
  86
  87   result = 0;
  88
  89   obp_fd = __open ("/proc/openprom", O_RDONLY);
  90   if (obp_fd != -1)
  91     {
  92       unsigned long int buf[4096 / sizeof (unsigned long int)];
  93       struct dirent *dirp = (struct dirent *) buf;
  94       ssize_t len;
  95
  96       while ((len = __getdents (obp_fd, (char *) dirp, sizeof (buf))) > 0)
  97         {
  98           struct dirent *this_dirp = dirp;
  99
 100           while (len > 0)
 101             {
 102               char node[strlen ("/proc/openprom/")
 103                         + _D_ALLOC_NAMLEN (this_dirp)
 104                         + strlen ("/clock-frequency")];
 105               char *prop;
 106               int fd;
 107
 108               /* Note that
 109                    strlen("/clock-frequency") > strlen("/device_type")
 110               */
 111               __stpcpy (prop = __stpcpy (__stpcpy (node, "/proc/openprom/"),
 112                                          this_dirp->d_name),
 113                         "/device_type");
 114               fd = __open (node, O_RDONLY);
 115               if (fd != -1)
 116                 {
 117                   char type_string[128];
 118                   int ret;
 119
 120                   ret = __read (fd, type_string, sizeof (type_string));
 121                   if (ret > 0 && strncmp (type_string, "'cpu'", 5) == 0)
 122                     {
 123                       int clkfreq_fd;
 124
 125                       __stpcpy (prop, "/clock-frequency");
 126                       clkfreq_fd = open (node, O_RDONLY);
 127                       if (clkfreq_fd != -1)
 128                         {
 129                           if (read (clkfreq_fd, type_string,
 130                                     sizeof (type_string)) > 0)
 131                             result = (hp_timing_t)
 132                               strtoull (type_string, NULL, 16);
 133                           close (clkfreq_fd);
 134                         }
 135                     }
 136                   __close (fd);
 137                 }
 138
 139               if (result != 0)
 140                 break;
 141
 142               len -= this_dirp->d_reclen;
 143               this_dirp = (struct dirent *)
 144                 ((char *) this_dirp + this_dirp->d_reclen);
 145             }
 146           if (result != 0)
 147             break;
 148         }
 149       __close (obp_fd);
 150     }
 151
 152   return result;
 153 }
 154
 155 static void set_obp_int (struct openpromio *op, int val)
 156 {
 157   char *cp = op->oprom_array;
 158   int *ip = (int *) cp;
 159
 160   *ip = val;
 161 }
 162
 163 static int get_obp_int (struct openpromio *op)
 164 {
 165   char *cp = op->oprom_array;
 166   int *ip = (int *) cp;
 167
 168   return *ip;
 169 }
 170
 171 static hp_timing_t
 172 __get_clockfreq_via_dev_openprom (void)
 173 {
 174   hp_timing_t result;
 175   int obp_dev_fd;
 176
 177   result = 0;
 178
 179   obp_dev_fd = __open ("/dev/openprom", O_RDONLY);
 180   if (obp_dev_fd != -1)
 181     {
 182       char obp_buf[8192];
 183       struct openpromio *obp_cmd = (struct openpromio *)obp_buf;
 184       int ret;
 185
 186       obp_cmd->oprom_size =
 187         sizeof (obp_buf) - sizeof (unsigned int);
 188       set_obp_int (obp_cmd, 0);
 189       ret = __ioctl (obp_dev_fd, OPROMCHILD, (char *) obp_cmd);
 190       if (ret == 0)
 191         {
 192           int cur_node = get_obp_int (obp_cmd);
 193
 194           while (cur_node != 0 && cur_node != -1)
 195             {
 196               obp_cmd->oprom_size = sizeof (obp_buf) - sizeof (unsigned int);
 197               strcpy (obp_cmd->oprom_array, "device_type");
 198               ret = __ioctl (obp_dev_fd, OPROMGETPROP, (char *) obp_cmd);
 199               if (ret == 0
 200                   && strncmp (obp_cmd->oprom_array, "cpu", 3) == 0)
 201                 {
 202                   obp_cmd->oprom_size = (sizeof (obp_buf)
 203                                          - sizeof (unsigned int));
 204                   strcpy (obp_cmd->oprom_array, "clock-frequency");
 205                   ret = __ioctl (obp_dev_fd, OPROMGETPROP, (char *) obp_cmd);
 206                   if (ret == 0)
 207                     result = (hp_timing_t) get_obp_int (obp_cmd);
 208                 }
 209               obp_cmd->oprom_size = sizeof (obp_buf) - sizeof (unsigned int);
 210               set_obp_int (obp_cmd, cur_node);
 211               ret = __ioctl (obp_dev_fd, OPROMNEXT, (char *) obp_cmd);
 212               if (ret < 0)
 213                 break;
 214               cur_node = get_obp_int (obp_cmd);
 215             }
 216         }
 217     }
 218
 219   return result;
 220 }
 221
 222 hp_timing_t
 223 __get_clockfreq (void)
 224 {
 225   static hp_timing_t result;
 226
 227   /* If this function was called before, we know the result.  */
 228   if (result != 0)
 229     return result;
 230
 231   /* We first read the information from the /proc/cpuinfo file.
 232      It contains at least one line like
 233         Cpu0ClkTick         : 000000002cb41780
 234      We search for this line and convert the number in an integer.  */
 235   result = __get_clockfreq_via_cpuinfo ();
 236   if (result != 0)
 237     return result;
 238
 239   /* If that did not work, try to find an OpenPROM node
 240      with device_type equal to 'cpu' using /dev/openprom
 241      and fetch the clock-frequency property from there.  */
 242   result = __get_clockfreq_via_dev_openprom ();
 243   if (result != 0)
 244     return result;
 245
 246   /* Finally, try the same lookup as above but using /proc/openprom.  */
 247   result = __get_clockfreq_via_proc_openprom ();
 248
 249   return result;
 250 }