gonzui

    1: /*
    2:  *----------------------------------------------------------------------
    3:  *    micro T-Kernel 3.00.00
    4:  *
    5:  *    Copyright (C) 2006-2019 by Ken Sakamura.
    6:  *    This software is distributed under the T-License 2.1.
    7:  *----------------------------------------------------------------------
    8:  *
    9:  *    Released by TRON Forum(http://www.tron.org) at 2019/12/11.
   10:  *
   11:  *----------------------------------------------------------------------
   12:  */
   13: /*
   14:  *      klock.c              Kernel Lock
   15:  *      Locked task is the highest run priority.
   16:  *      Unable to nest lock.
   17:  */
   18: 
   19: #include "kernel.h"
   20: #include "klock.h"
   21: #include "ready_queue.h"
   22: 
   23: /*
   24:  * Object lock
   25:  *      Do not call from critical section
   26:  */
   27: EXPORT void knl_LockOBJ( OBJLOCK *loc )
   28: {
   29:         BOOL   klocked;
   30: 
   31:   retry:
   32:         BEGIN_CRITICAL_SECTION;
   33:         klocked = knl_ctxtsk->klocked;
   34:         if ( !klocked ) {
   35:                 if ( loc->wtskq.next == NULL ) {
   36:                         /* Lock */
   37:                         QueInit(&loc->wtskq);
   38: 
   39:                         knl_ctxtsk->klocked = klocked = TRUE;
   40:                         knl_ready_queue.klocktsk = knl_ctxtsk;
   41:                 } else {
   42:                         /* Ready for lock */
   43:                         knl_ready_queue_delete(&knl_ready_queue, knl_ctxtsk);
   44:                         knl_ctxtsk->klockwait = TRUE;
   45:                         QueInsert(&knl_ctxtsk->tskque, &loc->wtskq);
   46: 
   47:                         knl_schedtsk = knl_ready_queue_top(&knl_ready_queue);
   48:                 }
   49:         }
   50:         END_CRITICAL_SECTION;
   51:         /* Since wait could be freed without getting lock, 
   52:            need to re-try if lock is not got */
   53:         if ( !klocked ) {
   54:                 goto retry;
   55:         }
   56: }
   57: 
   58: /*
   59:  * Object unlock
   60:  *      It may be called from a critical section.
   61:  */
   62: EXPORT void knl_UnlockOBJ( OBJLOCK *loc )
   63: {
   64:         TCB    *tcb;
   65: 
   66:         BEGIN_CRITICAL_SECTION;
   67:         knl_ctxtsk->klocked = FALSE;
   68:         knl_ready_queue.klocktsk = NULL;
   69: 
   70:         tcb = (TCB*)QueRemoveNext(&loc->wtskq);
   71:         if ( tcb == NULL ) {
   72:                 /* Free lock */
   73:                 loc->wtskq.next = NULL;
   74:         } else {
   75:                 /* Wake lock wait task */
   76:                 tcb->klockwait = FALSE;
   77:                 tcb->klocked = TRUE;
   78:                 knl_ready_queue_insert_top(&knl_ready_queue, tcb);
   79:         }
   80: 
   81:         knl_schedtsk = knl_ready_queue_top(&knl_ready_queue);
   82:         END_CRITICAL_SECTION;
   83: }