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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* 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 <stdbool.h>
#include "thread.h"
#include "panic.h"
#include "kernel.h"
#include "sh7034.h"
struct regs
{
unsigned int r[7]; /* Registers r8 thru r14 */
void *sp; /* Stack pointer (r15) */
unsigned int mach;
unsigned int macl;
unsigned int sr; /* Status register */
void* pr; /* Procedure register */
};
int num_threads;
static volatile int num_sleepers;
static int current_thread;
static struct regs thread_contexts[MAXTHREADS] __attribute__ ((section(".idata")));
char *thread_name[MAXTHREADS];
void *thread_stack[MAXTHREADS];
int thread_stack_size[MAXTHREADS];
static char main_thread_name[] = "main";
extern int stackbegin[];
extern int stackend[];
void switch_thread(void) __attribute__ ((section(".icode")));
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile ("add #48, %0\n\t"
"sts.l pr, @-%0\n\t"
"stc.l sr, @-%0\n\t"
"sts.l macl,@-%0\n\t"
"sts.l mach,@-%0\n\t"
"mov.l r15, @-%0\n\t"
"mov.l r14, @-%0\n\t"
"mov.l r13, @-%0\n\t"
"mov.l r12, @-%0\n\t"
"mov.l r11, @-%0\n\t"
"mov.l r10, @-%0\n\t"
"mov.l r9, @-%0\n\t"
"mov.l r8, @-%0" : : "r" (addr));
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(void* addr)
{
asm volatile ("mov.l @%0+,r8\n\t"
"mov.l @%0+,r9\n\t"
"mov.l @%0+,r10\n\t"
"mov.l @%0+,r11\n\t"
"mov.l @%0+,r12\n\t"
"mov.l @%0+,r13\n\t"
"mov.l @%0+,r14\n\t"
"mov.l @%0+,r15\n\t"
"lds.l @%0+,mach\n\t"
"lds.l @%0+,macl\n\t"
"ldc.l @%0+,sr\n\t"
"mov.l @%0,%0\n\t"
"lds %0,pr\n\t"
"mov.l %0, @(0, r15)" : "+r" (addr));
}
/*---------------------------------------------------------------------------
* Switch thread in round robin fashion.
*---------------------------------------------------------------------------
*/
void switch_thread(void)
{
int current;
int next;
unsigned int *stackptr;
#ifdef SIMULATOR
/* Do nothing */
#else
while (num_sleepers == num_threads)
{
/* Enter sleep mode, woken up on interrupt */
SBYCR &= 0x7F;
asm volatile ("sleep");
}
#endif
next = current = current_thread;
if (++next >= num_threads)
next = 0;
current_thread = next;
store_context(&thread_contexts[current]);
/* Check if the current thread stack is overflown */
stackptr = thread_stack[current];
if(stackptr[0] != 0xdeadbeef)
panicf("Stkov %s", thread_name[current]);
load_context(&thread_contexts[next]);
}
void sleep_thread(void)
{
++num_sleepers;
switch_thread();
}
void wake_up_thread(void)
{
num_sleepers = 0;
}
/*---------------------------------------------------------------------------
* Create thread.
* Return ID if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
int create_thread(void* function, void* stack, int stack_size, char *name)
{
unsigned int i;
unsigned int stacklen;
unsigned int *stackptr;
struct regs *regs;
if (num_threads >= MAXTHREADS)
return -1;
/* Munge the stack to make it easy to spot stack overflows */
stacklen = stack_size / 4;
stackptr = stack;
for(i = 0;i < stacklen;i++)
{
stackptr[i] = 0xdeadbeef;
}
/* Store interesting information */
thread_name[num_threads] = name;
thread_stack[num_threads] = stack;
thread_stack_size[num_threads] = stack_size;
regs = &thread_contexts[num_threads];
store_context(regs);
/* Subtract 4 to leave room for the PR push in load_context()
Align it on an even 32 bit boundary */
regs->sp = (void*)(((unsigned int)stack + stack_size - 4) & ~3);
regs->sr = 0;
regs->pr = function;
wake_up_thread();
return num_threads++; /* return the current ID, e.g for remove_thread() */
}
/*---------------------------------------------------------------------------
* Remove a thread from the scheduler.
* Parameter is the ID as returned from create_thread().
*---------------------------------------------------------------------------
*/
void remove_thread(int threadnum)
{
int i;
if(threadnum >= num_threads)
return;
num_threads--;
for (i=threadnum; i<num_threads-1; i++)
{ /* move all entries which are behind */
thread_name[i] = thread_name[i+1];
thread_stack[i] = thread_stack[i+1];
thread_stack_size[i] = thread_stack_size[i+1];
thread_contexts[i] = thread_contexts[i+1];
}
if (current_thread == threadnum) /* deleting the current one? */
current_thread = num_threads; /* set beyond last, avoid store harm */
else if (current_thread > threadnum) /* within the moved positions? */
current_thread--; /* adjust it, point to same context again */
}
void init_threads(void)
{
num_threads = 1; /* We have 1 thread to begin with */
current_thread = 0; /* The current thread is number 0 */
thread_name[0] = main_thread_name;
thread_stack[0] = stackbegin;
thread_stack_size[0] = (int)stackend - (int)stackbegin;
num_sleepers = 0;
}
int thread_stack_usage(int threadnum)
{
unsigned int i;
unsigned int *stackptr = thread_stack[threadnum];
if(threadnum >= num_threads)
return -1;
for(i = 0;i < thread_stack_size[threadnum]/sizeof(int);i++)
{
if(stackptr[i] != 0xdeadbeef)
break;
}
return ((thread_stack_size[threadnum] - i * 4) * 100) /
thread_stack_size[threadnum];
}
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