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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Björn Stenberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdlib.h>
#include "kernel.h"
#include "thread.h"
#include "sh7034.h"
#include "system.h"
#include "panic.h"
long current_tick = 0;
static void tick_start(unsigned int interval_in_ms);
/****************************************************************************
* Standard kernel stuff
****************************************************************************/
void kernel_init(void)
{
tick_start(1000/HZ);
}
void sleep(int ticks)
{
/* Always sleep at least 1 tick */
int timeout = current_tick + ticks + 1;
while (TIME_BEFORE( current_tick, timeout )) {
yield();
}
}
void yield(void)
{
switch_thread();
}
/****************************************************************************
* Interrupt level setting
****************************************************************************/
int set_irq_level(int level)
{
int i;
/* Read the old level and set the new one */
asm volatile ("stc sr, %0" : "=r" (i));
asm volatile ("ldc %0, sr" : : "r" (level << 4));
return (i >> 4) & 0x0f;
}
/****************************************************************************
* Queue handling stuff
****************************************************************************/
void queue_init(struct event_queue *q)
{
q->read = 0;
q->write = 0;
}
void queue_wait(struct event_queue *q, struct event *ev)
{
while(q->read == q->write)
{
switch_thread();
}
*ev = q->events[(q->read++) & QUEUE_LENGTH_MASK];
}
void queue_post(struct event_queue *q, int id, void *data)
{
int wr;
int oldlevel;
oldlevel = set_irq_level(15);
wr = (q->write++) & QUEUE_LENGTH_MASK;
q->events[wr].id = id;
q->events[wr].data = data;
set_irq_level(oldlevel);
}
/****************************************************************************
* Timer tick
****************************************************************************/
#define NUM_TICK_TASKS 4
void (*tick_funcs[NUM_TICK_TASKS])(void) = {NULL, NULL, NULL, NULL};
static void tick_start(unsigned int interval_in_ms)
{
unsigned int count;
count = FREQ / 1000 / 8 * interval_in_ms;
if(count > 0xffff)
{
panicf("Error! The tick interval is too long (%d ms)\n",
interval_in_ms);
return;
}
/* We are using timer 0 */
TSTR &= ~0x01; /* Stop the timer */
TSNC &= ~0x01; /* No synchronization */
TMDR &= ~0x01; /* Operate normally */
TCNT0 = 0; /* Start counting at 0 */
GRA0 = count;
TCR0 = 0x23; /* Clear at GRA match, sysclock/8 */
/* Enable interrupt on level 1 */
IPRC = (IPRC & ~0x00f0) | 0x0010;
TSR0 &= ~0x01;
TIER0 = 0xf9; /* Enable GRA match interrupt */
TSTR |= 0x01; /* Start timer 1 */
}
#pragma interrupt
void IMIA0(void)
{
int i;
/* Run through the list of tick tasks */
for(i = 0;i < NUM_TICK_TASKS;i++)
{
if(tick_funcs[i])
{
tick_funcs[i]();
}
}
current_tick++;
TSR0 &= ~0x01;
}
int tick_add_task(void (*f)(void))
{
int i;
int oldlevel = set_irq_level(15);
/* Add a task if there is room */
for(i = 0;i < NUM_TICK_TASKS;i++)
{
if(tick_funcs[i] == NULL)
{
tick_funcs[i] = f;
set_irq_level(oldlevel);
return 0;
}
}
set_irq_level(oldlevel);
return -1;
}
int tick_remove_task(void (*f)(void))
{
int i;
int oldlevel = set_irq_level(15);
/* Remove a task if it is there */
for(i = 0;i < NUM_TICK_TASKS;i++)
{
if(tick_funcs[i] == f)
{
tick_funcs[i] = NULL;
set_irq_level(oldlevel);
return 0;
}
}
set_irq_level(oldlevel);
return -1;
}
/****************************************************************************
* Simple mutex functions
****************************************************************************/
void mutex_init(struct mutex *m)
{
m->count = 0;
}
void mutex_lock(struct mutex *m)
{
/* Wait until the lock is open... */
while(m->count)
yield();
/* ...and lock it */
m->count++;
}
void mutex_unlock(struct mutex *m)
{
m->count--;
}
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