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linux/drivers/net/irda/sir_kthread.c

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/*********************************************************************
*
* sir_kthread.c: dedicated thread to process scheduled
* sir device setup requests
*
* Copyright (c) 2002 Martin Diehl
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
********************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <net/irda/irda.h>
#include "sir-dev.h"
/**************************************************************************
*
* kIrDAd kernel thread and config state machine
*
*/
struct irda_request_queue {
struct list_head request_list;
spinlock_t lock;
task_t *thread;
struct completion exit;
wait_queue_head_t kick, done;
atomic_t num_pending;
};
static struct irda_request_queue irda_rq_queue;
static int irda_queue_request(struct irda_request *rq)
{
int ret = 0;
unsigned long flags;
if (!test_and_set_bit(0, &rq->pending)) {
spin_lock_irqsave(&irda_rq_queue.lock, flags);
list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
wake_up(&irda_rq_queue.kick);
atomic_inc(&irda_rq_queue.num_pending);
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
ret = 1;
}
return ret;
}
static void irda_request_timer(unsigned long data)
{
struct irda_request *rq = (struct irda_request *)data;
unsigned long flags;
spin_lock_irqsave(&irda_rq_queue.lock, flags);
list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
wake_up(&irda_rq_queue.kick);
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
}
static int irda_queue_delayed_request(struct irda_request *rq, unsigned long delay)
{
int ret = 0;
struct timer_list *timer = &rq->timer;
if (!test_and_set_bit(0, &rq->pending)) {
timer->expires = jiffies + delay;
timer->function = irda_request_timer;
timer->data = (unsigned long)rq;
atomic_inc(&irda_rq_queue.num_pending);
add_timer(timer);
ret = 1;
}
return ret;
}
static void run_irda_queue(void)
{
unsigned long flags;
struct list_head *entry, *tmp;
struct irda_request *rq;
spin_lock_irqsave(&irda_rq_queue.lock, flags);
list_for_each_safe(entry, tmp, &irda_rq_queue.request_list) {
rq = list_entry(entry, struct irda_request, lh_request);
list_del_init(entry);
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
clear_bit(0, &rq->pending);
rq->func(rq->data);
if (atomic_dec_and_test(&irda_rq_queue.num_pending))
wake_up(&irda_rq_queue.done);
spin_lock_irqsave(&irda_rq_queue.lock, flags);
}
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
}
static int irda_thread(void *startup)
{
DECLARE_WAITQUEUE(wait, current);
daemonize("kIrDAd");
irda_rq_queue.thread = current;
complete((struct completion *)startup);
while (irda_rq_queue.thread != NULL) {
/* We use TASK_INTERRUPTIBLE, rather than
* TASK_UNINTERRUPTIBLE. Andrew Morton made this
* change ; he told me that it is safe, because "signal
* blocking is now handled in daemonize()", he added
* that the problem is that "uninterruptible sleep
* contributes to load average", making user worry.
* Jean II */
set_task_state(current, TASK_INTERRUPTIBLE);
add_wait_queue(&irda_rq_queue.kick, &wait);
if (list_empty(&irda_rq_queue.request_list))
schedule();
else
__set_task_state(current, TASK_RUNNING);
remove_wait_queue(&irda_rq_queue.kick, &wait);
/* make swsusp happy with our thread */
try_to_freeze();
run_irda_queue();
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,35)
reparent_to_init();
#endif
complete_and_exit(&irda_rq_queue.exit, 0);
/* never reached */
return 0;
}
static void flush_irda_queue(void)
{
if (atomic_read(&irda_rq_queue.num_pending)) {
DECLARE_WAITQUEUE(wait, current);
if (!list_empty(&irda_rq_queue.request_list))
run_irda_queue();
set_task_state(current, TASK_UNINTERRUPTIBLE);
add_wait_queue(&irda_rq_queue.done, &wait);
if (atomic_read(&irda_rq_queue.num_pending))
schedule();
else
__set_task_state(current, TASK_RUNNING);
remove_wait_queue(&irda_rq_queue.done, &wait);
}
}
/* substate handler of the config-fsm to handle the cases where we want
* to wait for transmit completion before changing the port configuration
*/
static int irda_tx_complete_fsm(struct sir_dev *dev)
{
struct sir_fsm *fsm = &dev->fsm;
unsigned next_state, delay;
unsigned bytes_left;
do {
next_state = fsm->substate; /* default: stay in current substate */
delay = 0;
switch(fsm->substate) {
case SIRDEV_STATE_WAIT_XMIT:
if (dev->drv->chars_in_buffer)
bytes_left = dev->drv->chars_in_buffer(dev);
else
bytes_left = 0;
if (!bytes_left) {
next_state = SIRDEV_STATE_WAIT_UNTIL_SENT;
break;
}
if (dev->speed > 115200)
delay = (bytes_left*8*10000) / (dev->speed/100);
else if (dev->speed > 0)
delay = (bytes_left*10*10000) / (dev->speed/100);
else
delay = 0;
/* expected delay (usec) until remaining bytes are sent */
if (delay < 100) {
udelay(delay);
delay = 0;
break;
}
/* sleep some longer delay (msec) */
delay = (delay+999) / 1000;
break;
case SIRDEV_STATE_WAIT_UNTIL_SENT:
/* block until underlaying hardware buffer are empty */
if (dev->drv->wait_until_sent)
dev->drv->wait_until_sent(dev);
next_state = SIRDEV_STATE_TX_DONE;
break;
case SIRDEV_STATE_TX_DONE:
return 0;
default:
IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
return -EINVAL;
}
fsm->substate = next_state;
} while (delay == 0);
return delay;
}
/*
* Function irda_config_fsm
*
* State machine to handle the configuration of the device (and attached dongle, if any).
* This handler is scheduled for execution in kIrDAd context, so we can sleep.
* however, kIrDAd is shared by all sir_dev devices so we better don't sleep there too
* long. Instead, for longer delays we start a timer to reschedule us later.
* On entry, fsm->sem is always locked and the netdev xmit queue stopped.
* Both must be unlocked/restarted on completion - but only on final exit.
*/
static void irda_config_fsm(void *data)
{
struct sir_dev *dev = data;
struct sir_fsm *fsm = &dev->fsm;
int next_state;
int ret = -1;
unsigned delay;
IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies);
do {
IRDA_DEBUG(3, "%s - state=0x%04x / substate=0x%04x\n",
__FUNCTION__, fsm->state, fsm->substate);
next_state = fsm->state;
delay = 0;
switch(fsm->state) {
case SIRDEV_STATE_DONGLE_OPEN:
if (dev->dongle_drv != NULL) {
ret = sirdev_put_dongle(dev);
if (ret) {
fsm->result = -EINVAL;
next_state = SIRDEV_STATE_ERROR;
break;
}
}
/* Initialize dongle */
ret = sirdev_get_dongle(dev, fsm->param);
if (ret) {
fsm->result = ret;
next_state = SIRDEV_STATE_ERROR;
break;
}
/* Dongles are powered through the modem control lines which
* were just set during open. Before resetting, let's wait for
* the power to stabilize. This is what some dongle drivers did
* in open before, while others didn't - should be safe anyway.
*/
delay = 50;
fsm->substate = SIRDEV_STATE_DONGLE_RESET;
next_state = SIRDEV_STATE_DONGLE_RESET;
fsm->param = 9600;
break;
case SIRDEV_STATE_DONGLE_CLOSE:
/* shouldn't we just treat this as success=? */
if (dev->dongle_drv == NULL) {
fsm->result = -EINVAL;
next_state = SIRDEV_STATE_ERROR;
break;
}
ret = sirdev_put_dongle(dev);
if (ret) {
fsm->result = ret;
next_state = SIRDEV_STATE_ERROR;
break;
}
next_state = SIRDEV_STATE_DONE;
break;
case SIRDEV_STATE_SET_DTR_RTS:
ret = sirdev_set_dtr_rts(dev,
(fsm->param&0x02) ? TRUE : FALSE,
(fsm->param&0x01) ? TRUE : FALSE);
next_state = SIRDEV_STATE_DONE;
break;
case SIRDEV_STATE_SET_SPEED:
fsm->substate = SIRDEV_STATE_WAIT_XMIT;
next_state = SIRDEV_STATE_DONGLE_CHECK;
break;
case SIRDEV_STATE_DONGLE_CHECK:
ret = irda_tx_complete_fsm(dev);
if (ret < 0) {
fsm->result = ret;
next_state = SIRDEV_STATE_ERROR;
break;
}
if ((delay=ret) != 0)
break;
if (dev->dongle_drv) {
fsm->substate = SIRDEV_STATE_DONGLE_RESET;
next_state = SIRDEV_STATE_DONGLE_RESET;
}
else {
dev->speed = fsm->param;
next_state = SIRDEV_STATE_PORT_SPEED;
}
break;
case SIRDEV_STATE_DONGLE_RESET:
if (dev->dongle_drv->reset) {
ret = dev->dongle_drv->reset(dev);
if (ret < 0) {
fsm->result = ret;
next_state = SIRDEV_STATE_ERROR;
break;
}
}
else
ret = 0;
if ((delay=ret) == 0) {
/* set serial port according to dongle default speed */
if (dev->drv->set_speed)
dev->drv->set_speed(dev, dev->speed);
fsm->substate = SIRDEV_STATE_DONGLE_SPEED;
next_state = SIRDEV_STATE_DONGLE_SPEED;
}
break;
case SIRDEV_STATE_DONGLE_SPEED:
if (dev->dongle_drv->reset) {
ret = dev->dongle_drv->set_speed(dev, fsm->param);
if (ret < 0) {
fsm->result = ret;
next_state = SIRDEV_STATE_ERROR;
break;
}
}
else
ret = 0;
if ((delay=ret) == 0)
next_state = SIRDEV_STATE_PORT_SPEED;
break;
case SIRDEV_STATE_PORT_SPEED:
/* Finally we are ready to change the serial port speed */
if (dev->drv->set_speed)
dev->drv->set_speed(dev, dev->speed);
dev->new_speed = 0;
next_state = SIRDEV_STATE_DONE;
break;
case SIRDEV_STATE_DONE:
/* Signal network layer so it can send more frames */
netif_wake_queue(dev->netdev);
next_state = SIRDEV_STATE_COMPLETE;
break;
default:
IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
fsm->result = -EINVAL;
/* fall thru */
case SIRDEV_STATE_ERROR:
IRDA_ERROR("%s - error: %d\n", __FUNCTION__, fsm->result);
#if 0 /* don't enable this before we have netdev->tx_timeout to recover */
netif_stop_queue(dev->netdev);
#else
netif_wake_queue(dev->netdev);
#endif
/* fall thru */
case SIRDEV_STATE_COMPLETE:
/* config change finished, so we are not busy any longer */
sirdev_enable_rx(dev);
up(&fsm->sem);
return;
}
fsm->state = next_state;
} while(!delay);
irda_queue_delayed_request(&fsm->rq, msecs_to_jiffies(delay));
}
/* schedule some device configuration task for execution by kIrDAd
* on behalf of the above state machine.
* can be called from process or interrupt/tasklet context.
*/
int sirdev_schedule_request(struct sir_dev *dev, int initial_state, unsigned param)
{
struct sir_fsm *fsm = &dev->fsm;
int xmit_was_down;
IRDA_DEBUG(2, "%s - state=0x%04x / param=%u\n", __FUNCTION__, initial_state, param);
if (down_trylock(&fsm->sem)) {
if (in_interrupt() || in_atomic() || irqs_disabled()) {
IRDA_DEBUG(1, "%s(), state machine busy!\n", __FUNCTION__);
return -EWOULDBLOCK;
} else
down(&fsm->sem);
}
if (fsm->state == SIRDEV_STATE_DEAD) {
/* race with sirdev_close should never happen */
IRDA_ERROR("%s(), instance staled!\n", __FUNCTION__);
up(&fsm->sem);
return -ESTALE; /* or better EPIPE? */
}
xmit_was_down = netif_queue_stopped(dev->netdev);
netif_stop_queue(dev->netdev);
atomic_set(&dev->enable_rx, 0);
fsm->state = initial_state;
fsm->param = param;
fsm->result = 0;
INIT_LIST_HEAD(&fsm->rq.lh_request);
fsm->rq.pending = 0;
fsm->rq.func = irda_config_fsm;
fsm->rq.data = dev;
if (!irda_queue_request(&fsm->rq)) { /* returns 0 on error! */
atomic_set(&dev->enable_rx, 1);
if (!xmit_was_down)
netif_wake_queue(dev->netdev);
up(&fsm->sem);
return -EAGAIN;
}
return 0;
}
int __init irda_thread_create(void)
{
struct completion startup;
int pid;
spin_lock_init(&irda_rq_queue.lock);
irda_rq_queue.thread = NULL;
INIT_LIST_HEAD(&irda_rq_queue.request_list);
init_waitqueue_head(&irda_rq_queue.kick);
init_waitqueue_head(&irda_rq_queue.done);
atomic_set(&irda_rq_queue.num_pending, 0);
init_completion(&startup);
pid = kernel_thread(irda_thread, &startup, CLONE_FS|CLONE_FILES);
if (pid <= 0)
return -EAGAIN;
else
wait_for_completion(&startup);
return 0;
}
void __exit irda_thread_join(void)
{
if (irda_rq_queue.thread) {
flush_irda_queue();
init_completion(&irda_rq_queue.exit);
irda_rq_queue.thread = NULL;
wake_up(&irda_rq_queue.kick);
wait_for_completion(&irda_rq_queue.exit);
}
}
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