/*
* Copyright (C) 2006 Ondrej Palkovsky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Lock ordering
*
* First the answerbox, then the phone
*/
#include <synch/waitq.h>
#include <ipc/ipc.h>
#include <errno.h>
#include <mm/slab.h>
#include <arch.h>
#include <proc/task.h>
#include <memstr.h>
#include <debug.h>
#include <print.h>
#include <proc/thread.h>
answerbox_t *ipc_central_box;
static slab_cache_t *ipc_call_slab;
/** Allocate & initialize call structure
*
* The call is initialized, so that the reply will be directed
* to TASK->answerbox
*/
call_t * ipc_call_alloc(void)
{
call_t *call;
call = slab_alloc(ipc_call_slab, 0);
memsetb((__address)call, sizeof(*call), 0);
call->callerbox = &TASK->answerbox;
return call;
}
/** Deallocate call stracuture */
void ipc_call_free(call_t *call)
{
slab_free(ipc_call_slab, call);
}
/** Initialize answerbox structure
*/
void ipc_answerbox_init(answerbox_t *box)
{
spinlock_initialize(&box->lock, "abox_lock");
waitq_initialize(&box->wq);
list_initialize(&box->connected_phones);
list_initialize(&box->calls);
list_initialize(&box->dispatched_calls);
list_initialize(&box->answers);
}
/** Initialize phone structure and connect phone to naswerbox
*/
void ipc_phone_init(phone_t *phone, answerbox_t *box)
{
spinlock_initialize(&phone->lock, "phone_lock");
phone->callee = box;
spinlock_lock(&box->lock);
list_append(&phone->list, &box->connected_phones);
spinlock_unlock(&box->lock);
}
/** Disconnect phone from answerbox */
void ipc_phone_destroy(phone_t *phone)
{
answerbox_t *box = phone->callee;
ASSERT(box);
spinlock_lock(&box->lock);
list_remove(&phone->list);
spinlock_unlock(&box->lock);
}
/** Send a request using phone to answerbox
*
* @param phone Phone connected to answerbox
* @param request Request to be sent
*/
void ipc_call(phone_t *phone, call_t *request)
{
answerbox_t *box = phone->callee;
ASSERT(box);
spinlock_lock(&box->lock);
list_append(&request->list, &box->calls);
spinlock_unlock(&box->lock);
waitq_wakeup(&box->wq, 0);
}
/** Answer message back to phone
*
* @param box Answerbox that is answering the message
* @param request Modified request that is being sent back
*/
void ipc_answer(answerbox_t *box, call_t *request)
{
answerbox_t *callerbox = request->callerbox;
request->flags |= IPC_CALL_ANSWERED;
spinlock_lock(&box->lock);
spinlock_lock(&callerbox->lock);
list_remove(&request->list);
list_append(&request->list, &callerbox->answers);
waitq_wakeup(&callerbox->wq, 0);
spinlock_unlock(&callerbox->lock);
spinlock_unlock(&box->lock);
}
/** Wait for phone call
*
* @return Recived message address
* - to distinguish between call and answer, look at call->flags
*/
call_t * ipc_wait_for_call(answerbox_t *box, int flags)
{
call_t *request;
if ((flags & IPC_WAIT_NONBLOCKING)) {
if (waitq_sleep_timeout(&box->wq,SYNCH_NO_TIMEOUT,SYNCH_NON_BLOCKING) == ESYNCH_WOULD_BLOCK)
return 0;
} else {
waitq_sleep(&box->wq);
}
// TODO - might need condition variable+mutex if we want to support
// removing of requests from queue before dispatch
spinlock_lock(&box->lock);
/* Handle answers first */
if (!list_empty(&box->answers)) {
request = list_get_instance(box->answers.next, call_t, list);
list_remove(&request->list);
} else {
ASSERT (! list_empty(&box->calls));
request = list_get_instance(box->calls.next, call_t, list);
list_remove(&request->list);
/* Append request to dispatch queue */
list_append(&request->list, &box->dispatched_calls);
}
spinlock_unlock(&box->lock);
return request;
}
/** Initilize ipc subsystem */
void ipc_init(void)
{
ipc_call_slab = slab_cache_create("ipc_call",
sizeof(call_t),
0,
NULL, NULL, 0);
}
static void ipc_phonecompany_thread(void *data)
{
call_t *call;
printf("Phone company started.\n"); while (1) {
call = ipc_wait_for_call(&TASK->answerbox, 0);
printf("Received phone call - %P %P\n", call->data[0], call->data[1]);
ipc_answer(&TASK->answerbox, call);
}
}
void ipc_create_phonecompany(void)
{
thread_t *t;
if ((t = thread_create(ipc_phonecompany_thread, "phonecompany",
TASK, 0)))
thread_ready(t);
else
panic("thread_create/phonecompany");
ipc_central_box = &TASK->answerbox;
}