1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
502 lines
12 KiB
C
502 lines
12 KiB
C
/*********************************************************************
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*
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* sir_kthread.c: dedicated thread to process scheduled
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* sir device setup requests
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*
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* Copyright (c) 2002 Martin Diehl
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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********************************************************************/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/version.h>
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#include <linux/init.h>
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#include <linux/smp_lock.h>
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <net/irda/irda.h>
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#include "sir-dev.h"
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/**************************************************************************
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*
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* kIrDAd kernel thread and config state machine
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*
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*/
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struct irda_request_queue {
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struct list_head request_list;
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spinlock_t lock;
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task_t *thread;
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struct completion exit;
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wait_queue_head_t kick, done;
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atomic_t num_pending;
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};
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static struct irda_request_queue irda_rq_queue;
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static int irda_queue_request(struct irda_request *rq)
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{
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int ret = 0;
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unsigned long flags;
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if (!test_and_set_bit(0, &rq->pending)) {
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spin_lock_irqsave(&irda_rq_queue.lock, flags);
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list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
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wake_up(&irda_rq_queue.kick);
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atomic_inc(&irda_rq_queue.num_pending);
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spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
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ret = 1;
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}
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return ret;
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}
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static void irda_request_timer(unsigned long data)
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{
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struct irda_request *rq = (struct irda_request *)data;
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unsigned long flags;
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spin_lock_irqsave(&irda_rq_queue.lock, flags);
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list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
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wake_up(&irda_rq_queue.kick);
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spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
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}
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static int irda_queue_delayed_request(struct irda_request *rq, unsigned long delay)
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{
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int ret = 0;
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struct timer_list *timer = &rq->timer;
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if (!test_and_set_bit(0, &rq->pending)) {
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timer->expires = jiffies + delay;
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timer->function = irda_request_timer;
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timer->data = (unsigned long)rq;
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atomic_inc(&irda_rq_queue.num_pending);
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add_timer(timer);
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ret = 1;
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}
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return ret;
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}
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static void run_irda_queue(void)
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{
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unsigned long flags;
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struct list_head *entry, *tmp;
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struct irda_request *rq;
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spin_lock_irqsave(&irda_rq_queue.lock, flags);
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list_for_each_safe(entry, tmp, &irda_rq_queue.request_list) {
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rq = list_entry(entry, struct irda_request, lh_request);
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list_del_init(entry);
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spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
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clear_bit(0, &rq->pending);
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rq->func(rq->data);
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if (atomic_dec_and_test(&irda_rq_queue.num_pending))
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wake_up(&irda_rq_queue.done);
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spin_lock_irqsave(&irda_rq_queue.lock, flags);
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}
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spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
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}
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static int irda_thread(void *startup)
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{
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DECLARE_WAITQUEUE(wait, current);
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daemonize("kIrDAd");
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irda_rq_queue.thread = current;
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complete((struct completion *)startup);
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while (irda_rq_queue.thread != NULL) {
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/* We use TASK_INTERRUPTIBLE, rather than
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* TASK_UNINTERRUPTIBLE. Andrew Morton made this
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* change ; he told me that it is safe, because "signal
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* blocking is now handled in daemonize()", he added
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* that the problem is that "uninterruptible sleep
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* contributes to load average", making user worry.
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* Jean II */
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set_task_state(current, TASK_INTERRUPTIBLE);
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add_wait_queue(&irda_rq_queue.kick, &wait);
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if (list_empty(&irda_rq_queue.request_list))
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schedule();
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else
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__set_task_state(current, TASK_RUNNING);
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remove_wait_queue(&irda_rq_queue.kick, &wait);
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/* make swsusp happy with our thread */
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if (current->flags & PF_FREEZE)
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refrigerator(PF_FREEZE);
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run_irda_queue();
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}
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,35)
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reparent_to_init();
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#endif
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complete_and_exit(&irda_rq_queue.exit, 0);
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/* never reached */
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return 0;
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}
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static void flush_irda_queue(void)
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{
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if (atomic_read(&irda_rq_queue.num_pending)) {
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DECLARE_WAITQUEUE(wait, current);
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if (!list_empty(&irda_rq_queue.request_list))
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run_irda_queue();
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set_task_state(current, TASK_UNINTERRUPTIBLE);
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add_wait_queue(&irda_rq_queue.done, &wait);
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if (atomic_read(&irda_rq_queue.num_pending))
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schedule();
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else
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__set_task_state(current, TASK_RUNNING);
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remove_wait_queue(&irda_rq_queue.done, &wait);
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}
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}
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/* substate handler of the config-fsm to handle the cases where we want
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* to wait for transmit completion before changing the port configuration
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*/
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static int irda_tx_complete_fsm(struct sir_dev *dev)
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{
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struct sir_fsm *fsm = &dev->fsm;
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unsigned next_state, delay;
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unsigned bytes_left;
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do {
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next_state = fsm->substate; /* default: stay in current substate */
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delay = 0;
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switch(fsm->substate) {
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case SIRDEV_STATE_WAIT_XMIT:
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if (dev->drv->chars_in_buffer)
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bytes_left = dev->drv->chars_in_buffer(dev);
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else
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bytes_left = 0;
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if (!bytes_left) {
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next_state = SIRDEV_STATE_WAIT_UNTIL_SENT;
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break;
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}
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if (dev->speed > 115200)
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delay = (bytes_left*8*10000) / (dev->speed/100);
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else if (dev->speed > 0)
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delay = (bytes_left*10*10000) / (dev->speed/100);
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else
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delay = 0;
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/* expected delay (usec) until remaining bytes are sent */
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if (delay < 100) {
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udelay(delay);
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delay = 0;
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break;
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}
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/* sleep some longer delay (msec) */
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delay = (delay+999) / 1000;
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break;
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case SIRDEV_STATE_WAIT_UNTIL_SENT:
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/* block until underlaying hardware buffer are empty */
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if (dev->drv->wait_until_sent)
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dev->drv->wait_until_sent(dev);
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next_state = SIRDEV_STATE_TX_DONE;
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break;
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case SIRDEV_STATE_TX_DONE:
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return 0;
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default:
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IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
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return -EINVAL;
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}
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fsm->substate = next_state;
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} while (delay == 0);
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return delay;
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}
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/*
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* Function irda_config_fsm
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*
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* State machine to handle the configuration of the device (and attached dongle, if any).
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* This handler is scheduled for execution in kIrDAd context, so we can sleep.
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* however, kIrDAd is shared by all sir_dev devices so we better don't sleep there too
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* long. Instead, for longer delays we start a timer to reschedule us later.
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* On entry, fsm->sem is always locked and the netdev xmit queue stopped.
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* Both must be unlocked/restarted on completion - but only on final exit.
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*/
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static void irda_config_fsm(void *data)
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{
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struct sir_dev *dev = data;
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struct sir_fsm *fsm = &dev->fsm;
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int next_state;
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int ret = -1;
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unsigned delay;
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IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies);
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do {
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IRDA_DEBUG(3, "%s - state=0x%04x / substate=0x%04x\n",
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__FUNCTION__, fsm->state, fsm->substate);
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next_state = fsm->state;
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delay = 0;
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switch(fsm->state) {
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case SIRDEV_STATE_DONGLE_OPEN:
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if (dev->dongle_drv != NULL) {
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ret = sirdev_put_dongle(dev);
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if (ret) {
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fsm->result = -EINVAL;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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}
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/* Initialize dongle */
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ret = sirdev_get_dongle(dev, fsm->param);
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if (ret) {
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fsm->result = ret;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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/* Dongles are powered through the modem control lines which
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* were just set during open. Before resetting, let's wait for
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* the power to stabilize. This is what some dongle drivers did
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* in open before, while others didn't - should be safe anyway.
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*/
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delay = 50;
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fsm->substate = SIRDEV_STATE_DONGLE_RESET;
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next_state = SIRDEV_STATE_DONGLE_RESET;
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fsm->param = 9600;
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break;
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case SIRDEV_STATE_DONGLE_CLOSE:
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/* shouldn't we just treat this as success=? */
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if (dev->dongle_drv == NULL) {
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fsm->result = -EINVAL;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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ret = sirdev_put_dongle(dev);
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if (ret) {
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fsm->result = ret;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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next_state = SIRDEV_STATE_DONE;
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break;
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case SIRDEV_STATE_SET_DTR_RTS:
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ret = sirdev_set_dtr_rts(dev,
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(fsm->param&0x02) ? TRUE : FALSE,
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(fsm->param&0x01) ? TRUE : FALSE);
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next_state = SIRDEV_STATE_DONE;
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break;
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case SIRDEV_STATE_SET_SPEED:
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fsm->substate = SIRDEV_STATE_WAIT_XMIT;
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next_state = SIRDEV_STATE_DONGLE_CHECK;
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break;
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case SIRDEV_STATE_DONGLE_CHECK:
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ret = irda_tx_complete_fsm(dev);
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if (ret < 0) {
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fsm->result = ret;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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if ((delay=ret) != 0)
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break;
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if (dev->dongle_drv) {
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fsm->substate = SIRDEV_STATE_DONGLE_RESET;
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next_state = SIRDEV_STATE_DONGLE_RESET;
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}
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else {
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dev->speed = fsm->param;
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next_state = SIRDEV_STATE_PORT_SPEED;
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}
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break;
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case SIRDEV_STATE_DONGLE_RESET:
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if (dev->dongle_drv->reset) {
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ret = dev->dongle_drv->reset(dev);
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if (ret < 0) {
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fsm->result = ret;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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}
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else
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ret = 0;
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if ((delay=ret) == 0) {
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/* set serial port according to dongle default speed */
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if (dev->drv->set_speed)
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dev->drv->set_speed(dev, dev->speed);
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fsm->substate = SIRDEV_STATE_DONGLE_SPEED;
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next_state = SIRDEV_STATE_DONGLE_SPEED;
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}
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break;
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case SIRDEV_STATE_DONGLE_SPEED:
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if (dev->dongle_drv->reset) {
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ret = dev->dongle_drv->set_speed(dev, fsm->param);
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if (ret < 0) {
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fsm->result = ret;
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next_state = SIRDEV_STATE_ERROR;
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break;
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}
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}
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else
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ret = 0;
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if ((delay=ret) == 0)
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next_state = SIRDEV_STATE_PORT_SPEED;
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break;
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case SIRDEV_STATE_PORT_SPEED:
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/* Finally we are ready to change the serial port speed */
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if (dev->drv->set_speed)
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dev->drv->set_speed(dev, dev->speed);
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dev->new_speed = 0;
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next_state = SIRDEV_STATE_DONE;
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break;
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case SIRDEV_STATE_DONE:
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/* Signal network layer so it can send more frames */
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netif_wake_queue(dev->netdev);
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next_state = SIRDEV_STATE_COMPLETE;
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break;
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default:
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IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
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fsm->result = -EINVAL;
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/* fall thru */
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case SIRDEV_STATE_ERROR:
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IRDA_ERROR("%s - error: %d\n", __FUNCTION__, fsm->result);
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#if 0 /* don't enable this before we have netdev->tx_timeout to recover */
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netif_stop_queue(dev->netdev);
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#else
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netif_wake_queue(dev->netdev);
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#endif
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/* fall thru */
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case SIRDEV_STATE_COMPLETE:
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/* config change finished, so we are not busy any longer */
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sirdev_enable_rx(dev);
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up(&fsm->sem);
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return;
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}
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fsm->state = next_state;
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} while(!delay);
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irda_queue_delayed_request(&fsm->rq, msecs_to_jiffies(delay));
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}
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/* schedule some device configuration task for execution by kIrDAd
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* on behalf of the above state machine.
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* can be called from process or interrupt/tasklet context.
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*/
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int sirdev_schedule_request(struct sir_dev *dev, int initial_state, unsigned param)
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{
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struct sir_fsm *fsm = &dev->fsm;
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int xmit_was_down;
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IRDA_DEBUG(2, "%s - state=0x%04x / param=%u\n", __FUNCTION__, initial_state, param);
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if (down_trylock(&fsm->sem)) {
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if (in_interrupt() || in_atomic() || irqs_disabled()) {
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IRDA_DEBUG(1, "%s(), state machine busy!\n", __FUNCTION__);
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return -EWOULDBLOCK;
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} else
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down(&fsm->sem);
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}
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if (fsm->state == SIRDEV_STATE_DEAD) {
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/* race with sirdev_close should never happen */
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IRDA_ERROR("%s(), instance staled!\n", __FUNCTION__);
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up(&fsm->sem);
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return -ESTALE; /* or better EPIPE? */
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}
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xmit_was_down = netif_queue_stopped(dev->netdev);
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netif_stop_queue(dev->netdev);
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atomic_set(&dev->enable_rx, 0);
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fsm->state = initial_state;
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fsm->param = param;
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fsm->result = 0;
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INIT_LIST_HEAD(&fsm->rq.lh_request);
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fsm->rq.pending = 0;
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fsm->rq.func = irda_config_fsm;
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fsm->rq.data = dev;
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if (!irda_queue_request(&fsm->rq)) { /* returns 0 on error! */
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atomic_set(&dev->enable_rx, 1);
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if (!xmit_was_down)
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netif_wake_queue(dev->netdev);
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up(&fsm->sem);
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return -EAGAIN;
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}
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return 0;
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}
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int __init irda_thread_create(void)
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{
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struct completion startup;
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int pid;
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spin_lock_init(&irda_rq_queue.lock);
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irda_rq_queue.thread = NULL;
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INIT_LIST_HEAD(&irda_rq_queue.request_list);
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init_waitqueue_head(&irda_rq_queue.kick);
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init_waitqueue_head(&irda_rq_queue.done);
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atomic_set(&irda_rq_queue.num_pending, 0);
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init_completion(&startup);
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pid = kernel_thread(irda_thread, &startup, CLONE_FS|CLONE_FILES);
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if (pid <= 0)
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return -EAGAIN;
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else
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wait_for_completion(&startup);
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return 0;
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}
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void __exit irda_thread_join(void)
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{
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if (irda_rq_queue.thread) {
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flush_irda_queue();
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init_completion(&irda_rq_queue.exit);
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irda_rq_queue.thread = NULL;
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wake_up(&irda_rq_queue.kick);
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wait_for_completion(&irda_rq_queue.exit);
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}
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}
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