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/*

 * 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);

}

/** Helper function to facilitate synchronous calls */

void ipc_call_sync(phone_t *phone, call_t *request)

{

	answerbox_t sync_box; 

	ipc_answerbox_init(&sync_box);

	/* We will receive data on special box */

	request->callerbox = &sync_box;

	ipc_call(phone, request);

	ipc_wait_for_call(&sync_box, 0);

}

/** Send a asynchronous 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]);

		call->data[0] = 0xbabaaaee;;

		call->data[1] = 0xaaaaeeee;

		ipc_answer(&TASK->answerbox, call);

		printf("Call answered.\n");

	}

}

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;

}