/*
* 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/spinlock.h>
#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>
/* Open channel that is assigned automatically to new tasks */
answerbox_t *ipc_phone_0 = NULL;
static slab_cache_t *ipc_call_slab;
/* Initialize new call */
static void _ipc_call_init(call_t *call)
{
memsetb((__address)call, sizeof(*call), 0);
call->callerbox = &TASK->answerbox;
call->sender = TASK;
}
/** 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);
_ipc_call_init(call);
return call;
}
/** Initialize allocated call */
void ipc_call_static_init(call_t *call)
{
_ipc_call_init(call);
call->flags |= IPC_CALL_STATIC_ALLOC;
}
/** 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, "ipc_box_lock");
waitq_initialize(&box->wq);
list_initialize(&box->connected_phones);
list_initialize(&box->calls);
list_initialize(&box->dispatched_calls);
list_initialize(&box->answers);
box->task = TASK;
}
/** Connect phone to answerbox */
void ipc_phone_connect(phone_t *phone, answerbox_t *box)
{
spinlock_lock(&phone->lock);
ASSERT(!phone->callee);
phone->busy = IPC_BUSY_CONNECTED;
phone->callee = box;
spinlock_lock(&box->lock);
list_append(&phone->list, &box->connected_phones);
spinlock_unlock(&box->lock);
spinlock_unlock(&phone->lock);
}
/** Initialize phone structure and connect phone to naswerbox
*/
void ipc_phone_init(phone_t *phone)
{
spinlock_initialize(&phone->lock, "phone_lock");
phone->callee = NULL;
phone->busy = IPC_BUSY_FREE;
atomic_set(&phone->active_calls, 0);
}
/** 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);
}
/** Answer message that was not dispatched and is not entered in
* any queue
*/
static void _ipc_answer_free_call(call_t *call)
{
answerbox_t *callerbox = call->callerbox;
call->flags &= ~IPC_CALL_DISPATCHED;
call->flags |= IPC_CALL_ANSWERED;
spinlock_lock(&callerbox->lock);
list_append(&call->list, &callerbox->answers);
spinlock_unlock(&callerbox->lock);
waitq_wakeup(&callerbox->wq, 0);
}
/** Answer message, that is in callee queue
*
* @param box Answerbox that is answering the message
* @param call Modified request that is being sent back
*/
void ipc_answer(answerbox_t *box, call_t *call)
{
/* Remove from active box */
spinlock_lock(&box->lock);
list_remove(&call->list);
spinlock_unlock(&box->lock);
/* Send back answer */
_ipc_answer_free_call(call);
}
/* Unsafe unchecking ipc_call */
static void _ipc_call(phone_t *phone, answerbox_t *box, call_t *call)
{
if (! (call->flags & IPC_CALL_FORWARDED)) {
atomic_inc(&phone->active_calls);
call->data.phone = phone;
}
spinlock_lock(&box->lock);
list_append(&call->list, &box->calls);
spinlock_unlock(&box->lock);
waitq_wakeup(&box->wq, 0);
}
/** Send a asynchronous request using phone to answerbox
*
* @param phone Phone connected to answerbox
* @param request Request to be sent
*/
int ipc_call(phone_t *phone, call_t *call)
{
answerbox_t *box;
spinlock_lock(&phone->lock);
box = phone->callee;
if (!box) {
/* Trying to send over disconnected phone */
spinlock_unlock(&phone->lock);
if (call->flags & IPC_CALL_FORWARDED) {
IPC_SET_RETVAL(call->data, EFORWARD);
} else { /* Simulate sending a message */
call->data.phone = phone;
atomic_inc(&phone->active_calls);
if (phone->busy == IPC_BUSY_CONNECTED)
IPC_SET_RETVAL(call->data, EHANGUP);
else
IPC_SET_RETVAL(call->data, ENOENT);
}
_ipc_answer_free_call(call);
return ENOENT;
}
_ipc_call(phone, box, call);
spinlock_unlock(&phone->lock);
return 0;
}
/** Disconnect phone from answerbox
*
* It is allowed to call disconnect on already disconnected phone
*
* @return 0 - phone disconnected, -1 - the phone was already disconnected
*/
int ipc_phone_hangup(phone_t *phone)
{
answerbox_t *box;
call_t *call;
spinlock_lock(&phone->lock);
box = phone->callee;
if (!box) {
if (phone->busy == IPC_BUSY_CONNECTING) {
spinlock_unlock(&phone->lock);
return -1;
}
/* Already disconnected phone */
phone->busy = IPC_BUSY_FREE;
spinlock_unlock(&phone->lock);
return 0;
}
spinlock_lock(&box->lock);
list_remove(&phone->list);
phone->callee = NULL;
spinlock_unlock(&box->lock);
call = ipc_call_alloc();
IPC_SET_METHOD(call->data, IPC_M_PHONE_HUNGUP);
call->flags |= IPC_CALL_DISCARD_ANSWER;
_ipc_call(phone, box, call);
phone->busy = IPC_BUSY_FREE;
spinlock_unlock(&phone->lock);
return 0;
}
/** Forwards call from one answerbox to a new one
*
* @param request Request to be forwarded
* @param newbox Target answerbox
* @param oldbox Old answerbox
* @return 0 on forward ok, error code, if there was error
*
* - the return value serves only as an information for the forwarder,
* the original caller is notified automatically with EFORWARD
*/
int ipc_forward(call_t *call, phone_t *newphone, answerbox_t *oldbox)
{
spinlock_lock(&oldbox->lock);
list_remove(&call->list);
spinlock_unlock(&oldbox->lock);
return ipc_call(newphone, call);
}
/** 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;
restart:
if (flags & IPC_WAIT_NONBLOCKING) {
if (waitq_sleep_timeout(&box->wq,0,1) == ESYNCH_WOULD_BLOCK)
return NULL;
} else
waitq_sleep(&box->wq);
spinlock_lock(&box->lock);
if (!list_empty(&box->answers)) {
/* Handle asynchronous answers */
request = list_get_instance(box->answers.next, call_t, list);
list_remove(&request->list);
atomic_dec(&request->data.phone->active_calls);
} else if (!list_empty(&box->calls)) {
/* Handle requests */
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);
request->flags |= IPC_CALL_DISPATCHED;
} else {
printf("WARNING: Spurious IPC wakeup.\n"); spinlock_unlock(&box->lock);
goto restart;
}
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);
}
/** Cleans up all IPC communication of the given task
*
*
*/
void ipc_cleanup(task_t *task)
{
int i;
/* Disconnect all our phones ('ipc_phone_hangup') */
for (i=0;i < IPC_MAX_PHONES; i++)
ipc_phone_hangup(&task->phones[i]);
/* Disconnect all phones connected to answerbox */
/* Answer all messages in 'calls' and 'dispatched_calls' queues */
/* Wait for all async answers to arrive */
}