source: rtems/c/src/lib/libbsp/hppa1.1/simhppa/shmsupp/lock.c @ 5626be2

4.104.114.84.95
Last change on this file since 5626be2 was 5626be2, checked in by Joel Sherrill <joel.sherrill@…>, on Sep 4, 2003 at 6:51:16 PM

2003-09-04 Joel Sherrill <joel@…>

  • include/bsp.h, shmsupp/addrconv.c, shmsupp/cause_intr.c, shmsupp/getcfg.c, shmsupp/lock.c, shmsupp/mpisr.c, startup/bspclean.c, startup/bspstart.c, startup/setvec.c, tools/print_dump.c, tty/tty.c: URL for license changed.
  • Property mode set to 100644
File size: 1.5 KB
Line 
1/*  Shared Memory Lock Routines
2 *
3 *  This shared memory locked queue support routine need to be
4 *  able to lock the specified locked queue.  Interrupts are
5 *  disabled while the queue is locked to prevent preemption
6 *  and deadlock when two tasks poll for the same lock.
7 *  previous level.
8 *
9 *  COPYRIGHT (c) 1989-1999.
10 *  On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.rtems.com/license/LICENSE.
15 *
16 *  $Id$
17 */
18
19#include <bsp.h>
20#include <shm_driver.h>
21
22/*
23 *  Shm_Initialize_lock
24 *
25 *  Initialize the lock for the specified locked queue.
26 */
27
28void Shm_Initialize_lock(
29  Shm_Locked_queue_Control *lq_cb
30)
31{
32  lq_cb->lock = LQ_UNLOCKED;
33}
34
35/*  Shm_Lock( &lq_cb )
36 *
37 *  This shared memory locked queue support routine locks the
38 *  specified locked queue.  It disables interrupts to prevent
39 *  a deadlock condition.
40 */
41
42void Shm_Lock(
43  Shm_Locked_queue_Control *lq_cb
44)
45{
46  rtems_unsigned32  isr_level;
47  vol_u32          *lockptr = &lq_cb->lock;
48  rtems_unsigned32  lock_value;
49
50  rtems_interrupt_disable( isr_level );
51
52    Shm_isrstat = isr_level;
53
54    do {
55      HPPA_ASM_LDCWS( 0, 0, lockptr, lock_value );
56    } while (lock_value == SHM_LOCK_VALUE);
57}
58
59/*
60 *  Shm_Unlock
61 *
62 *  Unlock the lock for the specified locked queue.
63 */
64
65void Shm_Unlock(
66  Shm_Locked_queue_Control *lq_cb
67)
68{
69  rtems_unsigned32 isr_level;
70
71  lq_cb->lock = SHM_UNLOCK_VALUE;
72  isr_level = Shm_isrstat;
73  rtems_interrupt_enable( isr_level );
74}
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