/*
 * Copyright (c) 2008 Jiri Svoboda
 * 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.
 */

/** @addtogroup genericipc
 * @{
 */
/** @file
 */

#include <synch/synch.h>
#include <synch/spinlock.h>
#include <synch/mutex.h>
#include <ipc/ipc.h>
#include <ipc/ipcrsc.h>
#include <arch.h>
#include <errno.h>
#include <debug.h>
#include <udebug/udebug_ipc.h>
#include <ipc/kbox.h>

void ipc_kbox_cleanup(void)
{
	bool have_kb_thread;

	/* Only hold kb_cleanup_lock while setting kb_finished - this is enough */
	mutex_lock(&TASK->kb_cleanup_lock);
	TASK->kb_finished = true;
	mutex_unlock(&TASK->kb_cleanup_lock);

	have_kb_thread = (TASK->kb_thread != NULL);

	/* From now on nobody will try to connect phones or attach kbox threads */

	/*
	 * Disconnect all phones connected to our kbox. Passing true for
	 * notify_box causes a HANGUP message to be inserted for each
	 * disconnected phone. This ensures the kbox thread is going to
	 * wake up and terminate.
	 */
	ipc_answerbox_slam_phones(&TASK->kernel_box, have_kb_thread);
	
	if (have_kb_thread) {
		LOG("join kb_thread..\n");
		thread_join(TASK->kb_thread);
		thread_detach(TASK->kb_thread);
		LOG("join done\n");
		TASK->kb_thread = NULL;
	}

	/* Answer all messages in 'calls' and 'dispatched_calls' queues */
	spinlock_lock(&TASK->kernel_box.lock);
	ipc_cleanup_call_list(&TASK->kernel_box.dispatched_calls);
	ipc_cleanup_call_list(&TASK->kernel_box.calls);
	spinlock_unlock(&TASK->kernel_box.lock);
}


static void kbox_thread_proc(void *arg)
{
	call_t *call;
	int method;
	bool done;
	ipl_t ipl;

	(void)arg;
	LOG("kbox_thread_proc()\n");
	done = false;

	while (!done) {
		call = ipc_wait_for_call(&TASK->kernel_box, SYNCH_NO_TIMEOUT,
			SYNCH_FLAGS_NONE);

		if (call != NULL) {
			method = IPC_GET_METHOD(call->data);

			if (method == IPC_M_DEBUG_ALL) {
				udebug_call_receive(call);
			}

			if (method == IPC_M_PHONE_HUNGUP) {
				LOG("kbox: handle hangup message\n");

				/* Was it our debugger, who hung up? */
				if (call->sender == TASK->udebug.debugger) {
					/* Terminate debugging session (if any) */
					LOG("kbox: terminate debug session\n");
					ipl = interrupts_disable();
					spinlock_lock(&TASK->lock);
					udebug_task_cleanup(TASK);
					spinlock_unlock(&TASK->lock);
					interrupts_restore(ipl);
				} else {
					LOG("kbox: was not debugger\n");
				}

				LOG("kbox: continue with hangup message\n");
				IPC_SET_RETVAL(call->data, 0);
				ipc_answer(&TASK->kernel_box, call);

				ipl = interrupts_disable();
				spinlock_lock(&TASK->lock);
				spinlock_lock(&TASK->answerbox.lock);
				if (list_empty(&TASK->answerbox.connected_phones)) {
					/* Last phone has been disconnected */
					TASK->kb_thread = NULL;
					done = true;
					LOG("phone list is empty\n");
				}
				spinlock_unlock(&TASK->answerbox.lock);
				spinlock_unlock(&TASK->lock);
				interrupts_restore(ipl);
			}
		}
	}

	LOG("kbox: finished\n");
}


/**
 * Connect phone to a task kernel-box specified by id.
 *
 * Note that this is not completely atomic. For optimisation reasons,
 * The task might start cleaning up kbox after the phone has been connected
 * and before a kbox thread has been created. This must be taken into account
 * in the cleanup code.
 *
 * @return 		Phone id on success, or negative error code.
 */
int ipc_connect_kbox(task_id_t taskid)
{
	int newphid;
	task_t *ta;
	thread_t *kb_thread;
	ipl_t ipl;

	ipl = interrupts_disable();
	spinlock_lock(&tasks_lock);

	ta = task_find_by_id(taskid);
	if (ta == NULL) {
		spinlock_unlock(&tasks_lock);
		interrupts_restore(ipl);
		return ENOENT;
	}

	atomic_inc(&ta->refcount);

	spinlock_unlock(&tasks_lock);
	interrupts_restore(ipl);

	mutex_lock(&ta->kb_cleanup_lock);

	if (atomic_predec(&ta->refcount) == 0) {
		mutex_unlock(&ta->kb_cleanup_lock);
		task_destroy(ta);
		return ENOENT;
	}

	if (ta->kb_finished != false) {
		mutex_unlock(&ta->kb_cleanup_lock);
		return EINVAL;
	}

	newphid = phone_alloc();
	if (newphid < 0) {
		mutex_unlock(&ta->kb_cleanup_lock);
		return ELIMIT;
	}

	/* Connect the newly allocated phone to the kbox */
	ipc_phone_connect(&TASK->phones[newphid], &ta->kernel_box);

	if (ta->kb_thread != NULL) {
		mutex_unlock(&ta->kb_cleanup_lock);
		return newphid;
	}

	/* Create a kbox thread */
	kb_thread = thread_create(kbox_thread_proc, NULL, ta, 0, "kbox", false);
	if (!kb_thread) {
		mutex_unlock(&ta->kb_cleanup_lock);
		return ENOMEM;
	}

	ta->kb_thread = kb_thread;
	thread_ready(kb_thread);

	mutex_unlock(&ta->kb_cleanup_lock);

	return newphid;
}

/** @}
 */