binutils-gdb/sim/ppc/hw_sem.c

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/* This file is part of the program psim.
Copyright (C) 1997,2008, Joel Sherrill <joel@OARcorp.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _HW_SEM_C_
#define _HW_SEM_C_
#include "device_table.h"
#ifdef HAVE_STRING_H
#include <string.h>
#else
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#endif
#include <sys/ipc.h>
#include <sys/sem.h>
#include <errno.h>
/* DEVICE
sem - provide access to a unix semaphore
DESCRIPTION
This device implements an interface to a unix semaphore.
PROPERTIES
reg = <address> <size> (required)
Determine where the memory lives in the parents address space.
key = <integer> (required)
This is the key of the unix semaphore.
EXAMPLES
Enable tracing of the sem:
| bash$ psim -t sem-device \
Configure a UNIX semaphore using key 0x12345678 mapped into psim
address space at 0xfff00000:
| -o '/sem@0xfff00000/reg 0xfff00000 0x80000' \
| -o '/sem@0xfff00000/key 0x12345678' \
sim/ppc/run -o '/#address-cells 1' \
-o '/sem@0xfff00000/reg 0xfff00000 12' \
-o '/sem@0xfff00000/key 0x12345678' ../psim-hello/hello
REGISTERS
offset 0 - lock count
offset 4 - lock operation
offset 8 - unlock operation
All reads return the current or resulting count.
BUGS
None known.
*/
typedef struct _hw_sem_device {
unsigned_word physical_address;
key_t key;
int id;
int initial;
int count;
} hw_sem_device;
#ifndef HAVE_UNION_SEMUN
union semun {
int val;
struct semid_ds *buf;
unsigned short int *array;
#if defined(__linux__)
struct seminfo *__buf;
#endif
};
#endif
static void
hw_sem_init_data(device *me)
{
hw_sem_device *sem = (hw_sem_device*)device_data(me);
const device_unit *d;
int status;
union semun help;
/* initialize the properties of the sem */
if (device_find_property(me, "key") == NULL)
error("sem_init_data() required key property is missing\n");
if (device_find_property(me, "value") == NULL)
error("sem_init_data() required value property is missing\n");
sem->key = (key_t) device_find_integer_property(me, "key");
DTRACE(sem, ("semaphore key (%d)\n", sem->key) );
sem->initial = (int) device_find_integer_property(me, "value");
DTRACE(sem, ("semaphore initial value (%d)\n", sem->initial) );
d = device_unit_address(me);
sem->physical_address = d->cells[ d->nr_cells-1 ];
DTRACE(sem, ("semaphore physical_address=0x%x\n", sem->physical_address));
/* Now to initialize the semaphore */
if ( sem->initial != -1 ) {
sem->id = semget(sem->key, 1, IPC_CREAT | 0660);
if (sem->id == -1)
error("hw_sem_init_data() semget failed\n");
help.val = sem->initial;
status = semctl( sem->id, 0, SETVAL, help );
if (status == -1)
error("hw_sem_init_data() semctl -- set value failed\n");
} else {
sem->id = semget(sem->key, 1, 0660);
if (sem->id == -1)
error("hw_sem_init_data() semget failed\n");
}
sem->count = semctl( sem->id, 0, GETVAL, help );
if (sem->count == -1)
error("hw_sem_init_data() semctl -- get value failed\n");
DTRACE(sem, ("semaphore OS value (%d)\n", sem->count) );
}
static void
hw_sem_attach_address_callback(device *me,
attach_type attach,
int space,
unsigned_word addr,
unsigned nr_bytes,
access_type access,
device *client) /*callback/default*/
{
hw_sem_device *sem = (hw_sem_device*)device_data(me);
if (space != 0)
error("sem_attach_address_callback() invalid address space\n");
if (nr_bytes == 12)
error("sem_attach_address_callback() invalid size\n");
sem->physical_address = addr;
DTRACE(sem, ("semaphore physical_address=0x%x\n", addr));
}
static unsigned
hw_sem_io_read_buffer(device *me,
void *dest,
int space,
unsigned_word addr,
unsigned nr_bytes,
cpu *processor,
unsigned_word cia)
{
hw_sem_device *sem = (hw_sem_device*)device_data(me);
struct sembuf sb;
int status;
unsigned32 u32;
union semun help;
/* do we need to worry about out of range addresses? */
DTRACE(sem, ("semaphore read addr=0x%x length=%d\n", addr, nr_bytes));
if (!(addr >= sem->physical_address && addr <= sem->physical_address + 11))
error("hw_sem_io_read_buffer() invalid address - out of range\n");
if ((addr % 4) != 0)
error("hw_sem_io_read_buffer() invalid address - alignment\n");
if (nr_bytes != 4)
error("hw_sem_io_read_buffer() invalid length\n");
switch ( (addr - sem->physical_address) / 4 ) {
case 0: /* OBTAIN CURRENT VALUE */
break;
case 1: /* LOCK */
sb.sem_num = 0;
sb.sem_op = -1;
sb.sem_flg = 0;
status = semop(sem->id, &sb, 1);
if (status == -1) {
perror( "hw_sem.c: lock" );
error("hw_sem_io_read_buffer() sem lock\n");
}
DTRACE(sem, ("semaphore lock %d\n", sem->count));
break;
case 2: /* UNLOCK */
sb.sem_num = 0;
sb.sem_op = 1;
sb.sem_flg = 0;
status = semop(sem->id, &sb, 1);
if (status == -1) {
perror( "hw_sem.c: unlock" );
error("hw_sem_io_read_buffer() sem unlock\n");
}
DTRACE(sem, ("semaphore unlock %d\n", sem->count));
break;
default:
error("hw_sem_io_read_buffer() invalid address - unknown error\n");
break;
}
/* assume target is big endian */
u32 = H2T_4(semctl( sem->id, 0, GETVAL, help ));
DTRACE(sem, ("semaphore OS value (%d)\n", u32) );
if (u32 == 0xffffffff) {
perror( "hw_sem.c: getval" );
error("hw_sem_io_read_buffer() semctl -- get value failed\n");
}
memcpy(dest, &u32, nr_bytes);
return nr_bytes;
}
static device_callbacks const hw_sem_callbacks = {
{ generic_device_init_address, hw_sem_init_data },
{ hw_sem_attach_address_callback, }, /* address */
{ hw_sem_io_read_buffer, NULL }, /* IO */
{ NULL, }, /* DMA */
{ NULL, }, /* interrupt */
{ NULL, }, /* unit */
NULL,
};
static void *
hw_sem_create(const char *name,
const device_unit *unit_address,
const char *args)
{
hw_sem_device *sem = ZALLOC(hw_sem_device);
return sem;
}
const device_descriptor hw_sem_device_descriptor[] = {
{ "sem", hw_sem_create, &hw_sem_callbacks },
{ NULL },
};
#endif /* _HW_SEM_C_ */