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rockbox/firmware/thread.c
Brandon Low 58e7547e89 Fix my warnings with explicit blocking on platforms w/o cpu_boost() 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11511 a1c6a512-1295-4272-9138-f99709370657
2006-11-11 05:53:32 +00:00

746 lines
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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 "config.h"
#include <stdbool.h>
#include "thread.h"
#include "panic.h"
#include "system.h"
#include "kernel.h"
#include "cpu.h"
#include "string.h"
#ifdef RB_PROFILE
#include <profile.h>
#endif
#define DEADBEEF ((unsigned int)0xdeadbeef)
/* Cast to the the machine int type, whose size could be < 4. */
struct core_entry cores[NUM_CORES] IBSS_ATTR;
#ifdef HAVE_PRIORITY_SCHEDULING
static unsigned short highest_priority IBSS_ATTR;
#endif
#ifdef HAVE_SCHEDULER_BOOSTCTRL
static int boosted_threads IBSS_ATTR;
#endif
/* Define to enable additional checks for blocking violations etc. */
#define THREAD_EXTRA_CHECKS
static const char main_thread_name[] = "main";
extern int stackbegin[];
extern int stackend[];
#ifdef CPU_PP
#ifndef BOOTLOADER
extern int cop_stackbegin[];
extern int cop_stackend[];
#else
/* The coprocessor stack is not set up in the bootloader code, but the threading
* is. No threads are run on the coprocessor, so set up some dummy stack */
int *cop_stackbegin = stackbegin;
int *cop_stackend = stackend;
#endif
#endif
/* Conserve IRAM
static void add_to_list(struct thread_entry **list,
struct thread_entry *thread) ICODE_ATTR;
static void remove_from_list(struct thread_entry **list,
struct thread_entry *thread) ICODE_ATTR;
*/
void switch_thread(bool save_context, struct thread_entry **blocked_list)
ICODE_ATTR;
static inline void store_context(void* addr) __attribute__ ((always_inline));
static inline void load_context(const void* addr)
__attribute__ ((always_inline));
#if defined(CPU_ARM)
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile(
"stmia %0, { r4-r11, sp, lr }\n"
: : "r" (addr)
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile(
"ldmia %0, { r4-r11, sp, lr }\n" /* load regs r4 to r14 from context */
"ldr r0, [%0, #40] \n" /* load start pointer */
"mov r1, #0 \n"
"cmp r0, r1 \n" /* check for NULL */
"strne r1, [%0, #40] \n" /* if it's NULL, we're already running */
"movne pc, r0 \n" /* not already running, so jump to start */
: : "r" (addr) : "r0", "r1"
);
}
#elif defined(CPU_COLDFIRE)
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile (
"move.l %%macsr,%%d0 \n"
"movem.l %%d0/%%d2-%%d7/%%a2-%%a7,(%0) \n"
: : "a" (addr) : "d0" /* only! */
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile (
"movem.l (%0),%%d0/%%d2-%%d7/%%a2-%%a7 \n" /* Load context */
"move.l %%d0,%%macsr \n"
"move.l (52,%0),%%d0 \n" /* Get start address */
"beq.b .running \n" /* NULL -> already running */
"clr.l (52,%0) \n" /* Clear start address.. */
"move.l %%d0,%0 \n"
"jmp (%0) \n" /* ..and start the thread */
".running: \n"
: : "a" (addr) : "d0" /* only! */
);
}
#elif CONFIG_CPU == SH7034
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile (
"add #36,%0 \n"
"sts.l pr, @-%0 \n"
"mov.l r15,@-%0 \n"
"mov.l r14,@-%0 \n"
"mov.l r13,@-%0 \n"
"mov.l r12,@-%0 \n"
"mov.l r11,@-%0 \n"
"mov.l r10,@-%0 \n"
"mov.l r9, @-%0 \n"
"mov.l r8, @-%0 \n"
: : "r" (addr)
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile (
"mov.l @%0+,r8 \n"
"mov.l @%0+,r9 \n"
"mov.l @%0+,r10 \n"
"mov.l @%0+,r11 \n"
"mov.l @%0+,r12 \n"
"mov.l @%0+,r13 \n"
"mov.l @%0+,r14 \n"
"mov.l @%0+,r15 \n"
"lds.l @%0+,pr \n"
"mov.l @%0,r0 \n" /* Get start address */
"tst r0,r0 \n"
"bt .running \n" /* NULL -> already running */
"lds r0,pr \n"
"mov #0,r0 \n"
"rts \n" /* Start the thread */
"mov.l r0,@%0 \n" /* Clear start address */
".running: \n"
: : "r" (addr) : "r0" /* only! */
);
}
#endif
static void add_to_list(struct thread_entry **list, struct thread_entry *thread)
{
if (*list == NULL)
{
thread->next = thread;
thread->prev = thread;
*list = thread;
}
else
{
/* Insert last */
thread->next = *list;
thread->prev = (*list)->prev;
thread->prev->next = thread;
(*list)->prev = thread;
/* Insert next
thread->next = (*list)->next;
thread->prev = *list;
thread->next->prev = thread;
(*list)->next = thread;
*/
}
}
static void remove_from_list(struct thread_entry **list,
struct thread_entry *thread)
{
if (list != NULL)
{
if (thread == thread->next)
{
*list = NULL;
return;
}
if (thread == *list)
*list = thread->next;
}
/* Fix links to jump over the removed entry. */
thread->prev->next = thread->next;
thread->next->prev = thread->prev;
}
/* Compiler trick: Don't declare as static to prevent putting
* function in IRAM. */
void check_sleepers(void)
{
struct thread_entry *current, *next;
/* Check sleeping threads. */
current = cores[CURRENT_CORE].sleeping;
if (current == NULL)
return ;
for (;;)
{
next = current->next;
if ((unsigned)current_tick >= GET_STATE_ARG(current->statearg))
{
/* Sleep timeout has been reached so bring the thread
* back to life again. */
remove_from_list(&cores[CURRENT_CORE].sleeping, current);
add_to_list(&cores[CURRENT_CORE].running, current);
current->statearg = 0;
/* If there is no more processes in the list, break the loop. */
if (cores[CURRENT_CORE].sleeping == NULL)
break;
current = next;
continue;
}
current = next;
/* Break the loop once we have walked through the list of all
* sleeping processes. */
if (current == cores[CURRENT_CORE].sleeping)
break;
}
}
static inline void sleep_core(void)
{
static long last_tick = 0;
for (;;)
{
if (last_tick != current_tick)
{
check_sleepers();
last_tick = current_tick;
}
/* We must sleep until there is at least one process in the list
* of running processes. */
if (cores[CURRENT_CORE].running != NULL)
break;
/* Enter sleep mode to reduce power usage, woken up on interrupt */
#ifdef CPU_COLDFIRE
asm volatile ("stop #0x2000");
#elif CONFIG_CPU == SH7034
and_b(0x7F, &SBYCR);
asm volatile ("sleep");
#elif CONFIG_CPU == PP5020
/* This should sleep the CPU. It appears to wake by itself on
interrupts */
CPU_CTL = 0x80000000;
#elif CONFIG_CPU == S3C2440
CLKCON |= 2;
#endif
}
}
#ifdef RB_PROFILE
static int get_threadnum(struct thread_entry *thread)
{
int i;
for (i = 0; i < MAXTHREADS; i++)
{
if (&cores[CURRENT_CORE].threads[i] == thread)
return i;
}
return -1;
}
void profile_thread(void) {
profstart(get_threadnum(cores[CURRENT_CORE].running));
}
#endif
/* Compiler trick: Don't declare as static to prevent putting
* function in IRAM. */
void change_thread_state(struct thread_entry **blocked_list)
{
struct thread_entry *old;
unsigned long new_state;
/* Remove the thread from the list of running threads. */
old = cores[CURRENT_CORE].running;
new_state = GET_STATE(old->statearg);
/* Check if a thread state change has been requested. */
if (new_state)
{
/* Change running thread state and switch to next thread. */
remove_from_list(&cores[CURRENT_CORE].running, old);
/* And put the thread into a new list of inactive threads. */
if (new_state == STATE_BLOCKED)
add_to_list(blocked_list, old);
else
add_to_list(&cores[CURRENT_CORE].sleeping, old);
#ifdef HAVE_PRIORITY_SCHEDULING
/* Reset priorities */
if (old->priority == highest_priority)
highest_priority = 100;
#endif
}
else
/* Switch to the next running thread. */
cores[CURRENT_CORE].running = old->next;
}
/*---------------------------------------------------------------------------
* Switch thread in round robin fashion.
*---------------------------------------------------------------------------
*/
void switch_thread(bool save_context, struct thread_entry **blocked_list)
{
#ifdef RB_PROFILE
profile_thread_stopped(get_threadnum(cores[CURRENT_CORE].running));
#endif
unsigned int *stackptr;
#ifdef SIMULATOR
/* Do nothing */
#else
/* Begin task switching by saving our current context so that we can
* restore the state of the current thread later to the point prior
* to this call. */
if (save_context)
{
store_context(&cores[CURRENT_CORE].running->context);
/* Check if the current thread stack is overflown */
stackptr = cores[CURRENT_CORE].running->stack;
if(stackptr[0] != DEADBEEF)
panicf("Stkov %s", cores[CURRENT_CORE].running->name);
/* Rearrange thread lists as needed */
change_thread_state(blocked_list);
}
/* Go through the list of sleeping task to check if we need to wake up
* any of them due to timeout. Also puts core into sleep state until
* there is at least one running process again. */
sleep_core();
#ifdef HAVE_PRIORITY_SCHEDULING
/* Select the new task based on priorities and the last time a process
* got CPU time. */
for (;;)
{
int priority = cores[CURRENT_CORE].running->priority;
if (priority < highest_priority)
highest_priority = priority;
if (priority == highest_priority ||
(current_tick - cores[CURRENT_CORE].running->last_run >
priority * 8))
break;
cores[CURRENT_CORE].running = cores[CURRENT_CORE].running->next;
}
/* Reset the value of thread's last running time to the current time. */
cores[CURRENT_CORE].running->last_run = current_tick;
#endif
#endif
/* And finally give control to the next thread. */
load_context(&cores[CURRENT_CORE].running->context);
#ifdef RB_PROFILE
profile_thread_started(get_threadnum(cores[CURRENT_CORE].running));
#endif
}
void sleep_thread(int ticks)
{
struct thread_entry *current;
current = cores[CURRENT_CORE].running;
#ifdef HAVE_SCHEDULER_BOOSTCTRL
if (STATE_IS_BOOSTED(current->statearg)) {
boosted_threads--;
if (!boosted_threads)
{
cpu_boost(false);
}
}
#endif
/* Set the thread's new state and timeout and finally force a task switch
* so that scheduler removes thread from the list of running processes
* and puts it in list of sleeping tasks. */
SET_STATE(current->statearg, STATE_SLEEPING, current_tick + ticks + 1);
switch_thread(true, NULL);
}
void block_thread(struct thread_entry **list)
{
struct thread_entry *current;
/* Get the entry for the current running thread. */
current = cores[CURRENT_CORE].running;
#ifdef HAVE_SCHEDULER_BOOSTCTRL
/* Keep the boosted state over indefinite block calls, because
* we are waiting until the earliest time that someone else
* completes an action */
unsigned long boost_flag = STATE_IS_BOOSTED(current->statearg);
#endif
#ifdef THREAD_EXTRA_CHECKS
/* We are not allowed to mix blocking types in one queue. */
if (*list && GET_STATE((*list)->statearg) == STATE_BLOCKED_W_TMO)
panicf("Blocking violation B->*T");
#endif
/* Set the state to blocked and ask the scheduler to switch tasks,
* this takes us off of the run queue until we are explicitly woken */
SET_STATE(current->statearg, STATE_BLOCKED, 0);
switch_thread(true, list);
#ifdef HAVE_SCHEDULER_BOOSTCTRL
/* Reset only the boosted flag to indicate we are up and running again. */
current->statearg = boost_flag;
#else
/* Clear all flags to indicate we are up and running again. */
current->statearg = 0;
#endif
}
void block_thread_w_tmo(struct thread_entry **list, int timeout)
{
struct thread_entry *current;
/* Get the entry for the current running thread. */
current = cores[CURRENT_CORE].running;
#ifdef HAVE_SCHEDULER_BOOSTCTRL
/* A block with a timeout is a sleep situation, whatever we are waiting
* for _may or may not_ happen, regardless of boost state, (user input
* for instance), so this thread no longer needs to boost */
if (STATE_IS_BOOSTED(current->statearg)) {
boosted_threads--;
if (!boosted_threads)
{
cpu_boost(false);
}
}
#endif
#ifdef THREAD_EXTRA_CHECKS
/* We can store only one thread to the "list" if thread is used
* in other list (such as core's list for sleeping tasks). */
if (*list)
panicf("Blocking violation T->*B");
#endif
/* Set the state to blocked with the specified timeout */
SET_STATE(current->statearg, STATE_BLOCKED_W_TMO, current_tick + timeout);
/* Set the "list" for explicit wakeup */
*list = current;
/* Now force a task switch and block until we have been woken up
* by another thread or timeout is reached. */
switch_thread(true, NULL);
/* It is now safe for another thread to block on this "list" */
*list = NULL;
}
void wakeup_thread(struct thread_entry **list)
{
struct thread_entry *thread;
/* Check if there is a blocked thread at all. */
if (*list == NULL)
return ;
/* Wake up the last thread first. */
thread = *list;
/* Determine thread's current state. */
switch (GET_STATE(thread->statearg))
{
case STATE_BLOCKED:
/* Remove thread from the list of blocked threads and add it
* to the scheduler's list of running processes. */
remove_from_list(list, thread);
add_to_list(&cores[CURRENT_CORE].running, thread);
case STATE_BLOCKED_W_TMO:
/* Just remove the timeout to cause scheduler to immediately
* wake up the thread. */
thread->statearg = 0;
break;
default:
/* Nothing to do. Thread has already been woken up
* or it's state is not blocked or blocked with timeout. */
return ;
}
}
/*---------------------------------------------------------------------------
* Create thread on the current core.
* Return ID if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
struct thread_entry*
create_thread(void (*function)(void), void* stack, int stack_size,
const char *name IF_PRIO(, int priority))
{
return create_thread_on_core(CURRENT_CORE, function, stack, stack_size,
name IF_PRIO(, priority));
}
/*---------------------------------------------------------------------------
* Create thread on a specific core.
* Return ID if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
struct thread_entry*
create_thread_on_core(unsigned int core, void (*function)(void),
void* stack, int stack_size,
const char *name IF_PRIO(, int priority))
{
unsigned int i;
unsigned int stacklen;
unsigned int *stackptr;
int n;
struct regs *regs;
struct thread_entry *thread;
for (n = 0; n < MAXTHREADS; n++)
{
if (cores[core].threads[n].name == NULL)
break;
}
if (n == MAXTHREADS)
return NULL;
/* Munge the stack to make it easy to spot stack overflows */
stacklen = stack_size / sizeof(int);
stackptr = stack;
for(i = 0;i < stacklen;i++)
{
stackptr[i] = DEADBEEF;
}
/* Store interesting information */
thread = &cores[core].threads[n];
thread->name = name;
thread->stack = stack;
thread->stack_size = stack_size;
thread->statearg = 0;
#ifdef HAVE_PRIORITY_SCHEDULING
thread->priority = priority;
highest_priority = 100;
#endif
add_to_list(&cores[core].running, thread);
regs = &thread->context;
/* Align stack to an even 32 bit boundary */
regs->sp = (void*)(((unsigned int)stack + stack_size) & ~3);
regs->start = (void*)function;
return thread;
}
#ifdef HAVE_SCHEDULER_BOOSTCTRL
void trigger_cpu_boost(void)
{
if (!STATE_IS_BOOSTED(cores[CURRENT_CORE].running->statearg))
{
SET_BOOST_STATE(cores[CURRENT_CORE].running->statearg);
if (!boosted_threads)
{
cpu_boost(true);
}
boosted_threads++;
}
}
#endif
/*---------------------------------------------------------------------------
* Remove a thread on the current core from the scheduler.
* Parameter is the ID as returned from create_thread().
*---------------------------------------------------------------------------
*/
void remove_thread(struct thread_entry *thread)
{
if (thread == NULL)
thread = cores[CURRENT_CORE].running;
/* Free the entry by removing thread name. */
thread->name = NULL;
#ifdef HAVE_PRIORITY_SCHEDULING
highest_priority = 100;
#endif
if (thread == cores[CURRENT_CORE].running)
{
remove_from_list(&cores[CURRENT_CORE].running, thread);
switch_thread(false, NULL);
return ;
}
if (thread == cores[CURRENT_CORE].sleeping)
remove_from_list(&cores[CURRENT_CORE].sleeping, thread);
else
remove_from_list(NULL, thread);
}
#ifdef HAVE_PRIORITY_SCHEDULING
int thread_set_priority(struct thread_entry *thread, int priority)
{
int old_priority;
if (thread == NULL)
thread = cores[CURRENT_CORE].running;
old_priority = thread->priority;
thread->priority = priority;
highest_priority = 100;
return old_priority;
}
int thread_get_priority(struct thread_entry *thread)
{
if (thread == NULL)
thread = cores[CURRENT_CORE].running;
return thread->priority;
}
#endif
void init_threads(void)
{
unsigned int core = CURRENT_CORE;
memset(cores, 0, sizeof cores);
cores[core].sleeping = NULL;
cores[core].running = NULL;
cores[core].threads[0].name = main_thread_name;
cores[core].threads[0].statearg = 0;
#ifdef HAVE_PRIORITY_SCHEDULING
cores[core].threads[0].priority = PRIORITY_USER_INTERFACE;
highest_priority = 100;
#endif
#ifdef HAVE_SCHEDULER_BOOSTCTRL
boosted_threads = 0;
#endif
add_to_list(&cores[core].running, &cores[core].threads[0]);
/* In multiple core setups, each core has a different stack. There is
* probably a much better way to do this. */
if (core == CPU)
{
cores[CPU].threads[0].stack = stackbegin;
cores[CPU].threads[0].stack_size = (int)stackend - (int)stackbegin;
} else {
#if NUM_CORES > 1 /* This code path will not be run on single core targets */
cores[COP].threads[0].stack = cop_stackbegin;
cores[COP].threads[0].stack_size =
(int)cop_stackend - (int)cop_stackbegin;
#endif
}
cores[core].threads[0].context.start = 0; /* thread 0 already running */
}
int thread_stack_usage(const struct thread_entry *thread)
{
unsigned int i;
unsigned int *stackptr = thread->stack;
for (i = 0;i < thread->stack_size/sizeof(int);i++)
{
if (stackptr[i] != DEADBEEF)
break;
}
return ((thread->stack_size - i * sizeof(int)) * 100) /
thread->stack_size;
}
int thread_get_status(const struct thread_entry *thread)
{
return GET_STATE(thread->statearg);
}
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