sim/ppc/hw_sem.c

   1 /*  This file is part of the program psim.
   2
   3     Copyright (C) 1997,2008, Joel Sherrill <joel@OARcorp.com>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program 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
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, see <http://www.gnu.org/licenses/>.
  17
  18     */
  19
  20
  21 #ifndef _HW_SEM_C_
  22 #define _HW_SEM_C_
  23
  24 #include "device_table.h"
  25
  26 #include <string.h>
  27 #include <sys/ipc.h>
  28 #include <sys/sem.h>
  29
  30 #include <errno.h>
  31
  32 /* DEVICE
  33
  34
  35    sem - provide access to a unix semaphore
  36
  37
  38    DESCRIPTION
  39
  40
  41    This device implements an interface to a unix semaphore.
  42
  43
  44    PROPERTIES
  45
  46
  47    reg = <address> <size> (required)
  48
  49    Determine where the memory lives in the parents address space.
  50
  51    key = <integer> (required)
  52
  53    This is the key of the unix semaphore.
  54
  55    EXAMPLES
  56
  57
  58    Enable tracing of the sem:
  59
  60    |  bash$ psim -t sem-device \
  61
  62
  63    Configure a UNIX semaphore using key 0x12345678 mapped into psim
  64    address space at 0xfff00000:
  65
  66    |  -o '/sem@0xfff00000/reg 0xfff00000 0x80000' \
  67    |  -o '/sem@0xfff00000/key 0x12345678' \
  68
  69    sim/ppc/run -o '/#address-cells 1' \
  70          -o '/sem@0xfff00000/reg 0xfff00000 12' \
  71          -o '/sem@0xfff00000/key 0x12345678' ../psim-hello/hello
  72
  73    REGISTERS
  74
  75    offset 0 - lock count
  76    offset 4 - lock operation
  77    offset 8 - unlock operation
  78
  79    All reads return the current or resulting count.
  80
  81    BUGS
  82
  83    None known.
  84
  85    */
  86
  87 typedef struct _hw_sem_device {
  88   unsigned_word physical_address;
  89   key_t key;
  90   int id;
  91   int initial;
  92   int count;
  93 } hw_sem_device;
  94
  95 #ifndef HAVE_UNION_SEMUN
  96 union semun {
  97   int val;
  98   struct semid_ds *buf;
  99   unsigned short int *array;
 100 #if defined(__linux__)
 101   struct seminfo *__buf;
 102 #endif
 103 };
 104 #endif
 105
 106 static void
 107 hw_sem_init_data(device *me)
 108 {
 109   hw_sem_device *sem = (hw_sem_device*)device_data(me);
 110   const device_unit *d;
 111   int status;
 112   union semun help;
 113
 114   /* initialize the properties of the sem */
 115
 116   if (device_find_property(me, "key") == NULL)
 117     error("sem_init_data() required key property is missing\n");
 118
 119   if (device_find_property(me, "value") == NULL)
 120     error("sem_init_data() required value property is missing\n");
 121
 122   sem->key = (key_t) device_find_integer_property(me, "key");
 123   DTRACE(sem, ("semaphore key (%d)\n", sem->key) );
 124
 125   sem->initial = (int) device_find_integer_property(me, "value");
 126   DTRACE(sem, ("semaphore initial value (%d)\n", sem->initial) );
 127
 128   d = device_unit_address(me);
 129   sem->physical_address = d->cells[ d->nr_cells-1 ];
 130   DTRACE(sem, ("semaphore physical_address=0x%x\n", sem->physical_address));
 131
 132   /* Now to initialize the semaphore */
 133
 134   if ( sem->initial != -1 ) {
 135
 136     sem->id = semget(sem->key, 1, IPC_CREAT | 0660);
 137     if (sem->id == -1)
 138       error("hw_sem_init_data() semget failed\n");
 139
 140     help.val = sem->initial;
 141     status = semctl( sem->id, 0, SETVAL, help );
 142     if (status == -1)
 143       error("hw_sem_init_data() semctl -- set value failed\n");
 144
 145   } else {
 146     sem->id = semget(sem->key, 1, 0660);
 147     if (sem->id == -1)
 148       error("hw_sem_init_data() semget failed\n");
 149   }
 150
 151   sem->count = semctl( sem->id, 0, GETVAL, help );
 152   if (sem->count == -1)
 153     error("hw_sem_init_data() semctl -- get value failed\n");
 154   DTRACE(sem, ("semaphore OS value (%d)\n", sem->count) );
 155 }
 156
 157 static void
 158 hw_sem_attach_address_callback(device *me,
 159                                 attach_type attach,
 160                                 int space,
 161                                 unsigned_word addr,
 162                                 unsigned nr_bytes,
 163                                 access_type access,
 164                                 device *client) /*callback/default*/
 165 {
 166   hw_sem_device *sem = (hw_sem_device*)device_data(me);
 167
 168   if (space != 0)
 169     error("sem_attach_address_callback() invalid address space\n");
 170
 171   if (nr_bytes == 12)
 172     error("sem_attach_address_callback() invalid size\n");
 173
 174   sem->physical_address = addr;
 175   DTRACE(sem, ("semaphore physical_address=0x%x\n", addr));
 176 }
 177
 178 static unsigned
 179 hw_sem_io_read_buffer(device *me,
 180                          void *dest,
 181                          int space,
 182                          unsigned_word addr,
 183                          unsigned nr_bytes,
 184                          cpu *processor,
 185                          unsigned_word cia)
 186 {
 187   hw_sem_device *sem = (hw_sem_device*)device_data(me);
 188   struct sembuf sb;
 189   int status;
 190   uint32_t u32;
 191   union semun help;
 192
 193   /* do we need to worry about out of range addresses? */
 194
 195   DTRACE(sem, ("semaphore read addr=0x%x length=%d\n", addr, nr_bytes));
 196
 197   if (!(addr >= sem->physical_address && addr <= sem->physical_address + 11))
 198     error("hw_sem_io_read_buffer() invalid address - out of range\n");
 199
 200   if ((addr % 4) != 0)
 201     error("hw_sem_io_read_buffer() invalid address - alignment\n");
 202
 203   if (nr_bytes != 4)
 204     error("hw_sem_io_read_buffer() invalid length\n");
 205
 206   switch ( (addr - sem->physical_address) / 4 ) {
 207
 208     case 0:  /* OBTAIN CURRENT VALUE */
 209       break;
 210
 211     case 1:  /* LOCK */
 212       sb.sem_num = 0;
 213       sb.sem_op  = -1;
 214       sb.sem_flg = 0;
 215
 216       status = semop(sem->id, &sb, 1);
 217       if (status == -1) {
 218         perror( "hw_sem.c: lock" );
 219         error("hw_sem_io_read_buffer() sem lock\n");
 220       }
 221
 222       DTRACE(sem, ("semaphore lock %d\n", sem->count));
 223       break;
 224
 225     case 2: /* UNLOCK */
 226       sb.sem_num = 0;
 227       sb.sem_op  = 1;
 228       sb.sem_flg = 0;
 229
 230       status = semop(sem->id, &sb, 1);
 231       if (status == -1) {
 232         perror( "hw_sem.c: unlock" );
 233         error("hw_sem_io_read_buffer() sem unlock\n");
 234       }
 235       DTRACE(sem, ("semaphore unlock %d\n", sem->count));
 236       break;
 237
 238     default:
 239       error("hw_sem_io_read_buffer() invalid address - unknown error\n");
 240       break;
 241   }
 242
 243   /* assume target is big endian */
 244   u32 = H2T_4(semctl( sem->id, 0, GETVAL, help ));
 245
 246   DTRACE(sem, ("semaphore OS value (%d)\n", u32) );
 247   if (u32 == 0xffffffff) {
 248     perror( "hw_sem.c: getval" );
 249     error("hw_sem_io_read_buffer() semctl -- get value failed\n");
 250   }
 251
 252   memcpy(dest, &u32, nr_bytes);
 253   return nr_bytes;
 254
 255 }
 256
 257 static device_callbacks const hw_sem_callbacks = {
 258   { generic_device_init_address, hw_sem_init_data },
 259   { hw_sem_attach_address_callback, }, /* address */
 260   { hw_sem_io_read_buffer, NULL }, /* IO */
 261   { NULL, }, /* DMA */
 262   { NULL, }, /* interrupt */
 263   { NULL, }, /* unit */
 264   NULL,
 265 };
 266
 267 static void *
 268 hw_sem_create(const char *name,
 269                  const device_unit *unit_address,
 270                  const char *args)
 271 {
 272   hw_sem_device *sem = ZALLOC(hw_sem_device);
 273   return sem;
 274 }
 275
 276 const device_descriptor hw_sem_device_descriptor[] = {
 277   { "sem", hw_sem_create, &hw_sem_callbacks },
 278   { NULL },
 279 };
 280
 281 #endif /* _HW_SEM_C_ */