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92bdeb2888
Some compilers don't understand the semctl API and think it's an input argument even when it's used as an output, and then complains that it is being used uninitialized. Zero it out explicitly to workaround it. This adds some runtime overhead, but should be fairly minor as it's a small stack buffer, and shouldn't be that relevant relative to all the other logic in these functions.
292 lines
6.8 KiB
C
292 lines
6.8 KiB
C
/* This file is part of the program psim.
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Copyright (C) 1997,2008, Joel Sherrill <joel@OARcorp.com>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _HW_SEM_C_
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#define _HW_SEM_C_
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#include "device_table.h"
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#include <string.h>
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#include <sys/ipc.h>
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#include <sys/sem.h>
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#include <errno.h>
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/* DEVICE
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sem - provide access to a unix semaphore
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DESCRIPTION
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This device implements an interface to a unix semaphore.
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PROPERTIES
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reg = <address> <size> (required)
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Determine where the memory lives in the parents address space.
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key = <integer> (required)
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This is the key of the unix semaphore.
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EXAMPLES
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Enable tracing of the sem:
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| bash$ psim -t sem-device \
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Configure a UNIX semaphore using key 0x12345678 mapped into psim
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address space at 0xfff00000:
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| -o '/sem@0xfff00000/reg 0xfff00000 0x80000' \
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| -o '/sem@0xfff00000/key 0x12345678' \
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sim/ppc/run -o '/#address-cells 1' \
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-o '/sem@0xfff00000/reg 0xfff00000 12' \
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-o '/sem@0xfff00000/key 0x12345678' ../psim-hello/hello
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REGISTERS
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offset 0 - lock count
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offset 4 - lock operation
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offset 8 - unlock operation
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All reads return the current or resulting count.
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BUGS
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None known.
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*/
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#ifdef HAVE_SYSV_SEM
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typedef struct _hw_sem_device {
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unsigned_word physical_address;
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key_t key;
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int id;
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int initial;
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int count;
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} hw_sem_device;
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#ifndef HAVE_UNION_SEMUN
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union semun {
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int val;
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struct semid_ds *buf;
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unsigned short int *array;
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#if defined(__linux__)
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struct seminfo *__buf;
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#endif
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};
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#endif
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static void
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hw_sem_init_data(device *me)
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{
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hw_sem_device *sem = (hw_sem_device*)device_data(me);
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const device_unit *d;
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int status;
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union semun help = {};
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/* initialize the properties of the sem */
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if (device_find_property(me, "key") == NULL)
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error("sem_init_data() required key property is missing\n");
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if (device_find_property(me, "value") == NULL)
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error("sem_init_data() required value property is missing\n");
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sem->key = (key_t) device_find_integer_property(me, "key");
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DTRACE(sem, ("semaphore key (%d)\n", sem->key) );
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sem->initial = (int) device_find_integer_property(me, "value");
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DTRACE(sem, ("semaphore initial value (%d)\n", sem->initial) );
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d = device_unit_address(me);
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sem->physical_address = d->cells[ d->nr_cells-1 ];
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DTRACE(sem, ("semaphore physical_address=0x%x\n", sem->physical_address));
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/* Now to initialize the semaphore */
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if ( sem->initial != -1 ) {
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sem->id = semget(sem->key, 1, IPC_CREAT | 0660);
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if (sem->id == -1)
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error("hw_sem_init_data() semget failed\n");
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help.val = sem->initial;
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status = semctl( sem->id, 0, SETVAL, help );
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if (status == -1)
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error("hw_sem_init_data() semctl -- set value failed\n");
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} else {
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sem->id = semget(sem->key, 1, 0660);
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if (sem->id == -1)
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error("hw_sem_init_data() semget failed\n");
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}
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sem->count = semctl( sem->id, 0, GETVAL, help );
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if (sem->count == -1)
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error("hw_sem_init_data() semctl -- get value failed\n");
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DTRACE(sem, ("semaphore OS value (%d)\n", sem->count) );
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}
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static void
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hw_sem_attach_address_callback(device *me,
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attach_type attach,
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int space,
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unsigned_word addr,
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unsigned nr_bytes,
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access_type access,
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device *client) /*callback/default*/
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{
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hw_sem_device *sem = (hw_sem_device*)device_data(me);
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if (space != 0)
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error("sem_attach_address_callback() invalid address space\n");
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if (nr_bytes == 12)
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error("sem_attach_address_callback() invalid size\n");
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sem->physical_address = addr;
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DTRACE(sem, ("semaphore physical_address=0x%x\n", addr));
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}
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static unsigned
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hw_sem_io_read_buffer(device *me,
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void *dest,
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int space,
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unsigned_word addr,
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unsigned nr_bytes,
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cpu *processor,
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unsigned_word cia)
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{
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hw_sem_device *sem = (hw_sem_device*)device_data(me);
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struct sembuf sb;
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int status;
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uint32_t u32;
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union semun help = {};
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/* do we need to worry about out of range addresses? */
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DTRACE(sem, ("semaphore read addr=0x%x length=%d\n", addr, nr_bytes));
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if (!(addr >= sem->physical_address && addr <= sem->physical_address + 11))
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error("hw_sem_io_read_buffer() invalid address - out of range\n");
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if ((addr % 4) != 0)
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error("hw_sem_io_read_buffer() invalid address - alignment\n");
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if (nr_bytes != 4)
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error("hw_sem_io_read_buffer() invalid length\n");
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switch ( (addr - sem->physical_address) / 4 ) {
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case 0: /* OBTAIN CURRENT VALUE */
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break;
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case 1: /* LOCK */
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sb.sem_num = 0;
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sb.sem_op = -1;
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sb.sem_flg = 0;
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status = semop(sem->id, &sb, 1);
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if (status == -1) {
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perror( "hw_sem.c: lock" );
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error("hw_sem_io_read_buffer() sem lock\n");
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}
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DTRACE(sem, ("semaphore lock %d\n", sem->count));
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break;
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case 2: /* UNLOCK */
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sb.sem_num = 0;
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sb.sem_op = 1;
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sb.sem_flg = 0;
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status = semop(sem->id, &sb, 1);
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if (status == -1) {
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perror( "hw_sem.c: unlock" );
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error("hw_sem_io_read_buffer() sem unlock\n");
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}
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DTRACE(sem, ("semaphore unlock %d\n", sem->count));
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break;
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default:
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error("hw_sem_io_read_buffer() invalid address - unknown error\n");
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break;
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}
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/* assume target is big endian */
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u32 = H2T_4(semctl( sem->id, 0, GETVAL, help ));
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DTRACE(sem, ("semaphore OS value (%d)\n", u32) );
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if (u32 == 0xffffffff) {
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perror( "hw_sem.c: getval" );
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error("hw_sem_io_read_buffer() semctl -- get value failed\n");
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}
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memcpy(dest, &u32, nr_bytes);
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return nr_bytes;
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}
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static device_callbacks const hw_sem_callbacks = {
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{ generic_device_init_address, hw_sem_init_data },
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{ hw_sem_attach_address_callback, }, /* address */
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{ hw_sem_io_read_buffer, NULL }, /* IO */
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{ NULL, }, /* DMA */
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{ NULL, }, /* interrupt */
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{ NULL, }, /* unit */
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NULL,
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};
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static void *
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hw_sem_create(const char *name,
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const device_unit *unit_address,
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const char *args)
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{
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hw_sem_device *sem = ZALLOC(hw_sem_device);
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return sem;
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}
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const device_descriptor hw_sem_device_descriptor[] = {
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{ "sem", hw_sem_create, &hw_sem_callbacks },
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{ NULL },
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};
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#else
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const device_descriptor hw_sem_device_descriptor[] = {
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{ NULL },
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};
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#endif /* HAVE_SYSV_SEM */
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#endif /* _HW_SEM_C_ */
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