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/*
* Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup core_mbox
* @{
*
* @file
* @brief mailbox implementation
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
*
* @}
*/
#include <string.h>
#include "mbox.h"
#include "irq.h"
#include "sched.h"
#include "thread.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
static void _wake_waiter(thread_t *thread, unsigned irqstate)
{
sched_set_status(thread, STATUS_PENDING);
DEBUG("mbox: Thread %"PRIkernel_pid": _wake_waiter(): waking up "
"%"PRIkernel_pid".\n", sched_active_pid, thread->pid);
uint16_t process_priority = thread->priority;
irq_restore(irqstate);
sched_switch(process_priority);
}
static void _wait(list_node_t *wait_list, unsigned irqstate)
{
DEBUG("mbox: Thread %"PRIkernel_pid" _wait(): going blocked.\n",
sched_active_pid);
thread_t *me = (thread_t*) sched_active_thread;
sched_set_status(me, STATUS_MBOX_BLOCKED);
thread_add_to_list(wait_list, me);
irq_restore(irqstate);
thread_yield();
DEBUG("mbox: Thread %"PRIkernel_pid" _wait(): woke up.\n",
sched_active_pid);
}
int _mbox_put(mbox_t *mbox, msg_t *msg, int blocking)
{
unsigned irqstate = irq_disable();
list_node_t *next = (list_node_t*) list_remove_head(&mbox->readers);
if (next) {
DEBUG("mbox: Thread %"PRIkernel_pid" mbox 0x%08x: _tryput(): "
"there's a waiter.\n", sched_active_pid, (unsigned)mbox);
thread_t *thread = container_of((clist_node_t*)next, thread_t, rq_entry);
*(msg_t *)thread->wait_data = *msg;
_wake_waiter(thread, irqstate);
return 1;
}
else {
if (cib_full(&mbox->cib)) {
if (blocking) {
_wait(&mbox->writers, irqstate);
irqstate = irq_disable();
}
else {
irq_restore(irqstate);
return 0;
}
}
DEBUG("mbox: Thread %"PRIkernel_pid" mbox 0x%08x: _tryput(): "
"queued message.\n", sched_active_pid, (unsigned)mbox);
msg->sender_pid = sched_active_pid;
/* copy msg into queue */
mbox->msg_array[cib_put_unsafe(&mbox->cib)] = *msg;
irq_restore(irqstate);
return 1;
}
}
int _mbox_get(mbox_t *mbox, msg_t *msg, int blocking)
{
unsigned irqstate = irq_disable();
if (cib_avail(&mbox->cib)) {
DEBUG("mbox: Thread %"PRIkernel_pid" mbox 0x%08x: _tryget(): "
"got queued message.\n", sched_active_pid, (unsigned)mbox);
/* copy msg from queue */
*msg = mbox->msg_array[cib_get_unsafe(&mbox->cib)];
list_node_t *next = (list_node_t*) list_remove_head(&mbox->writers);
if (next) {
thread_t *thread = container_of((clist_node_t*)next, thread_t, rq_entry);
_wake_waiter(thread, irqstate);
}
else {
irq_restore(irqstate);
}
return 1;
}
else if (blocking) {
sched_active_thread->wait_data = (void*)msg;
_wait(&mbox->readers, irqstate);
/* sender has copied message */
return 1;
}
else {
irq_restore(irqstate);
return 0;
}
}