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/*
* Copyright (c) 2011 Aeroflex Gaisler
*
* BSD license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <asm-leon/contextswitch.h>
#include <asm-leon/leonbare_kernel.h>
#include <asm-leon/leonbare_debug.h>
#include <asm-leon/stack.h>
#include <asm-leon/leonstack.h>
#include <asm-leon/irq.h>
struct leonbare_kernel leonbare_kernel;
/*
* queue 0: [ <acc=2>],
* queue 1: [ <acc=10>, <acc=8>,<acc=8>,<acc=1> ],
* queue 2: [ ... ],
* ...
* queue n: [ ... ]
*
* Seach through ready queue [0 - LEONBARE_RUNQ_READY_NR-1] for the
* first thread in a queue'ss head to discover
* leonbare_thread_tick_callback() will put threads that have their th_caccount
* consumed into the prepare-run queues. th_caccount is already initialized
* to the value for the next schedule round. So all there is to do is to
* move the to prepare-run queues to run queues [0 - LEONBARE_RUNQ_READY_NR-1].
* return the first thread in any queue, similary to leonbare_sched_next().
* Using LEONBARE_KR_RUNQ_WHICH and leonbare_thread.th_runq_which one can
* determine weather the thread is in a runqueue or a prepare-runqueue:
* LEONBARE_KR_RUNQ_WHICH == leonbare_thread.th_runq_which : thread in runqueue
* LEONBARE_KR_RUNQ_WHICH != leonbare_thread.th_runq_which : thread in prepare-runqueue
* after a leonbare_thread_tick_callback() or a run queue change, call
* leonbare_sched_update() to update LEONBARE_KR_NEXT and
* LEONBARE_KR_NEED_SCHEDULE
*/
int
leonbare_sched_update ()
{
int idx;
leonbare_thread_t n = 0;
int i = 0;
LEONBARE_VERIFYIRQDISABLED ();
LEONBARE_VERIFYSCHED ();
for (i = 0; i < LEONBARE_RUNQ_READY_NR; i++)
{
leonbare_thread_t c;
if (!LBTAILQ_EMPTY (LEONBARE_KR_RUNQ (i)))
{
n = LBTAILQ_FIRST (LEONBARE_KR_RUNQ (i));
break;
}
}
if (!n)
{
for (idx = 0; idx < LEONBARE_RUNQ_READY_NR; idx++)
{
struct leonbare_thread_queue *h0 =
(struct leonbare_thread_queue *) LEONBARE_KR_RUNQ (idx);
struct leonbare_thread_queue *h1 = (struct leonbare_thread_queue *)
LEONBARE_KR_RUNQ (idx + LEONBARE_RUNQ_PREPARE_IDX);
if (LBTAILQ_EMPTY (h1))
{
LBTAILQ_INIT (h0);
}
else
{
*h0 = *h1;
if (LBTAILQ_FIRST (h0))
{
LBTAILQ_FIRST (h0)->th_runq.tqe_prev = &(h0)->tqh_first;
}
if (!n)
{
n = LBTAILQ_FIRST (h0);
}
}
}
for (idx = 0; idx < LEONBARE_RUNQ_READY_NR; idx++)
{
LBTAILQ_INIT (LEONBARE_KR_RUNQ (idx + LEONBARE_RUNQ_PREPARE_IDX));
}
LEONBARE_KR_RUNQ_WHICH++;
LEONBARE_VERIFYSCHED ();
LEONBARE_PRINTQUEUES ();
}
LEONBARE_KR_NEXT = n;
return (LEONBARE_KR_NEED_SCHEDULE);
}
/* called in the timer irq handling. Decrements the
* th_caccount field. On consumption of th_caccount the
* thread will be removed from the ready queue nad placed into the
* prepare-runqueue for later readdition by leonbare_sched_readyprepare()
* called from gettimeofday.c's installed ticker_callback callback
* leonbare_thread_tick_callback() might change the kernel state in which case
* state on return from leonbare_thread_tick_callback() leonbare_thread_schedule_callback()
* will be called from rtrap_fast.S .
*/
int
leonbare_thread_tick_callback ()
{
LEONBARE_PROTECT_DECL (flags);
unsigned int r;
volatile leonbare_thread_t c = LEONBARE_KR_CURRENT;
leonbare_thread_t i;
LBDEBUG_FNCALL;
if (c && LEONBARE_KR_IS_PREEMPTION)
{
LEONBARE_PROTECT_KERNEL_START ();
{
LEONBARE_VERIFYIRQDISABLED ();
LEONBARE_VERIFYSCHED ();
if ((--c->th_caccount) < 0)
{
LBDEBUG_HEADER_PRINTF (LBDEBUG_QUEUE_NR, "remove %s(%x)\n",
LEONBARE_TH_NAME_DBG (c), c);
LBTAILQ_REMOVE (LEONBARE_KR_RUNQ (c->th_runq_idx), c, th_runq);
LBTAILQ_INSERT_TAIL (LEONBARE_KR_RUNQ
(c->th_runq_idx + LEONBARE_RUNQ_PREPARE_IDX),
c, th_runq);
c->th_caccount = c->th_account;
c->th_runq_which++;
}
else
{
/* todo: round robbin scheme */
}
}
LEONBARE_PROTECT_KERNEL_END ();
}
r = leonbare_sched_update ();
return r;
}
/* called from rtrap_fast.S's installed schedule_callback callback */
int
leonbare_thread_schedule_callback (struct leonbare_pt_regs *ptregs)
{
unsigned int retval;
LBDEBUG_FNCALL;
if (LEONBARE_KR_IS_IN_KERNEL == 0 && LEONBARE_KR_NEED_SCHEDULE)
{
leonbare_sched ();
//KERNEL_ENTER;
//KERNEL_EXIT(LEONBARE_KR_NEED_SCHEDULE, retval);
}
LBDEBUG_FNEXIT;
}
struct leonbare_thread _thread_main;
int
leonbare_thread_init ()
{
int i;
LBDEBUG_FNCALL;
memset ((void *) &_thread_main, 0, sizeof (_thread_main));
_thread_main.th_reentp = _impure_ptr;
_thread_main.th_name = "<main>";
_thread_main.th_runq_idx = 0;
_thread_main.th_pri_idx = 0;
_thread_main.th_account = 0;
LBTAILQ_INIT (LEONBARE_KR_ALLQ);
for (i = 0; i < LEONBARE_RUNQ_NR; i++)
{
LBTAILQ_INIT (LEONBARE_KR_RUNQ (i));
}
LBTAILQ_INIT (LEONBARE_KR_ALLM);
/* queues */
LBTAILQ_INSERT_TAIL (LEONBARE_KR_ALLQ, &_thread_main, th_allq);
/* inseart into ready queue 0 at head */
LBTAILQ_INSERT_HEAD (LEONBARE_KR_RUNQ (_thread_main.th_runq_idx),
&_thread_main, th_runq);
LEONBARE_KR_CURRENT = &_thread_main;
LEONBARE_KR_IS_IN_KERNEL = 0;
leonbare_init_ticks ();
schedule_callback = (schedulehandler) leonbare_thread_schedule_callback;
ticker_callback = (tickerhandler) leonbare_thread_tick_callback;
/* disable later */
LEONBARE_KR_IS_PREEMPTION = 1;
LBDEBUG_FNEXIT;
}
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