sched-rt.h

/*
 * Copyright (C) 2008 Philippe Gerum <rpm@xenomai.org>.
 *
 * Xenomai 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 2 of the License,
 * or (at your option) any later version.
 *
 * Xenomai 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 Xenomai; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */
#ifndef _COBALT_KERNEL_SCHED_RT_H
#define _COBALT_KERNEL_SCHED_RT_H

#ifndef _COBALT_KERNEL_SCHED_H
#error "please don't include cobalt/kernel/sched-rt.h directly"
#endif

/*
 * Global priority scale for Xenomai's core scheduling class,
 * available to SCHED_COBALT members.
 */
#define XNSCHED_CORE_MIN_PRIO   0
#define XNSCHED_CORE_MAX_PRIO   259
#define XNSCHED_CORE_NR_PRIO    \
        (XNSCHED_CORE_MAX_PRIO - XNSCHED_CORE_MIN_PRIO + 1)

/*
 * Priority range for SCHED_FIFO, and all other classes Cobalt
 * implements except SCHED_COBALT.
 */
#define XNSCHED_FIFO_MIN_PRIO   1
#define XNSCHED_FIFO_MAX_PRIO   256

#if XNSCHED_CORE_NR_PRIO > XNSCHED_CLASS_WEIGHT_FACTOR ||       \
  (defined(CONFIG_XENO_OPT_SCALABLE_SCHED) &&                   \
   XNSCHED_CORE_NR_PRIO > XNSCHED_MLQ_LEVELS)
#error "XNSCHED_MLQ_LEVELS is too low"
#endif

extern struct xnsched_class xnsched_class_rt;

static inline void __xnsched_rt_requeue(struct xnthread *thread)
{
        xnsched_addq(&thread->sched->rt.runnable, thread);
}

static inline void __xnsched_rt_enqueue(struct xnthread *thread)
{
        xnsched_addq_tail(&thread->sched->rt.runnable, thread);
}

static inline void __xnsched_rt_dequeue(struct xnthread *thread)
{
        xnsched_delq(&thread->sched->rt.runnable, thread);
}

static inline void __xnsched_rt_track_weakness(struct xnthread *thread)
{
        /*
         * We have to track threads exiting weak scheduling, i.e. any
         * thread leaving the WEAK class code if compiled in, or
         * assigned a zero priority if weak threads are hosted by the
         * RT class.
         *
         * CAUTION: since we need to check the effective priority
         * level for determining the weakness state, this can only
         * apply to non-boosted threads.
         */
        if (IS_ENABLED(CONFIG_XENO_OPT_SCHED_WEAK) || thread->cprio)
                xnthread_clear_state(thread, XNWEAK);
        else
                xnthread_set_state(thread, XNWEAK);
}

static inline bool __xnsched_rt_setparam(struct xnthread *thread,
                                         const union xnsched_policy_param *p)
{
        bool ret = xnsched_set_effective_priority(thread, p->rt.prio);
        
        if (!xnthread_test_state(thread, XNBOOST))
                __xnsched_rt_track_weakness(thread);

        return ret;
}

static inline void __xnsched_rt_getparam(struct xnthread *thread,
                                         union xnsched_policy_param *p)
{
        p->rt.prio = thread->cprio;
}

static inline void __xnsched_rt_trackprio(struct xnthread *thread,
                                          const union xnsched_policy_param *p)
{
        if (p)
                thread->cprio = p->rt.prio; /* Force update. */
        else {
                thread->cprio = thread->bprio;
                /* Leaving PI/PP, so non-boosted by definition. */
                __xnsched_rt_track_weakness(thread);
        }
}

static inline void __xnsched_rt_protectprio(struct xnthread *thread, int prio)
{
        /*
         * The RT class supports the widest priority range from
         * XNSCHED_CORE_MIN_PRIO to XNSCHED_CORE_MAX_PRIO inclusive,
         * no need to cap the input value which is guaranteed to be in
         * the range [1..XNSCHED_CORE_MAX_PRIO].
         */
        thread->cprio = prio;
}

static inline void __xnsched_rt_forget(struct xnthread *thread)
{
}

static inline int xnsched_rt_init_thread(struct xnthread *thread)
{
        return 0;
}

#ifdef CONFIG_XENO_OPT_SCHED_CLASSES
struct xnthread *xnsched_rt_pick(struct xnsched *sched);
#else
static inline struct xnthread *xnsched_rt_pick(struct xnsched *sched)
{
        return xnsched_getq(&sched->rt.runnable);
}
#endif

void xnsched_rt_tick(struct xnsched *sched);

#endif /* !_COBALT_KERNEL_SCHED_RT_H */