psim/mpci/lock.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*  Shared Memory Lock Routines
0004  *
0005  *  This shared memory locked queue support routine need to be
0006  *  able to lock the specified locked queue.  Interrupts are
0007  *  disabled while the queue is locked to prevent preemption
0008  *  and deadlock when two tasks poll for the same lock.
0009  *  previous level.
0010  *
0011  *  COPYRIGHT (c) 1989-2008.
0012  *  On-Line Applications Research Corporation (OAR).
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #include <rtems.h>
0037 #include <bsp.h>
0038 #include <shm_driver.h>
0039 #include <psim.h>
0040
0041 /*
0042  *  Shm_Initialize_lock
0043  *
0044  *  Initialize the lock for the specified locked queue.
0045  */
0046
0047 void Shm_Initialize_lock(
0048   Shm_Locked_queue_Control *lq_cb
0049 )
0050 {
0051   /* nothing required -- done implicitly by device tree */
0052 }
0053
0054 /*  void _Shm_Lock( &lq_cb )
0055  *
0056  *  This shared memory locked queue support routine locks the
0057  *  specified locked queue.  It disables interrupts to prevent
0058  *  a deadlock condition.
0059  */
0060
0061 static rtems_interrupt_level level;
0062
0063 void Shm_Lock(
0064   Shm_Locked_queue_Control *lq_cb
0065 )
0066 {
0067   rtems_interrupt_disable( level );
0068     (void) PSIM.Semaphore.lock;
0069 }
0070
0071 /*
0072  *  Shm_Unlock
0073  *
0074  *  Unlock the lock for the specified locked queue.
0075  */
0076
0077 void Shm_Unlock(
0078   Shm_Locked_queue_Control *lq_cb
0079 )
0080 {
0081     (void) PSIM.Semaphore.unlock;
0082   rtems_interrupt_enable( level );
0083 }