/spare/repo/libata-dev branch 'v2.6.13'
[linux-2.6] / drivers / net / irda / sir_kthread.c
1 /*********************************************************************
2  *
3  *      sir_kthread.c:          dedicated thread to process scheduled
4  *                              sir device setup requests
5  *
6  *      Copyright (c) 2002 Martin Diehl
7  *
8  *      This program is free software; you can redistribute it and/or 
9  *      modify it under the terms of the GNU General Public License as 
10  *      published by the Free Software Foundation; either version 2 of 
11  *      the License, or (at your option) any later version.
12  *
13  ********************************************************************/    
14
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/version.h>
18 #include <linux/init.h>
19 #include <linux/smp_lock.h>
20 #include <linux/completion.h>
21 #include <linux/delay.h>
22
23 #include <net/irda/irda.h>
24
25 #include "sir-dev.h"
26
27 /**************************************************************************
28  *
29  * kIrDAd kernel thread and config state machine
30  *
31  */
32
33 struct irda_request_queue {
34         struct list_head request_list;
35         spinlock_t lock;
36         task_t *thread;
37         struct completion exit;
38         wait_queue_head_t kick, done;
39         atomic_t num_pending;
40 };
41
42 static struct irda_request_queue irda_rq_queue;
43
44 static int irda_queue_request(struct irda_request *rq)
45 {
46         int ret = 0;
47         unsigned long flags;
48
49         if (!test_and_set_bit(0, &rq->pending)) {
50                 spin_lock_irqsave(&irda_rq_queue.lock, flags);
51                 list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
52                 wake_up(&irda_rq_queue.kick);
53                 atomic_inc(&irda_rq_queue.num_pending);
54                 spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
55                 ret = 1;
56         }
57         return ret;
58 }
59
60 static void irda_request_timer(unsigned long data)
61 {
62         struct irda_request *rq = (struct irda_request *)data;
63         unsigned long flags;
64         
65         spin_lock_irqsave(&irda_rq_queue.lock, flags);
66         list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
67         wake_up(&irda_rq_queue.kick);
68         spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
69 }
70
71 static int irda_queue_delayed_request(struct irda_request *rq, unsigned long delay)
72 {
73         int ret = 0;
74         struct timer_list *timer = &rq->timer;
75
76         if (!test_and_set_bit(0, &rq->pending)) {
77                 timer->expires = jiffies + delay;
78                 timer->function = irda_request_timer;
79                 timer->data = (unsigned long)rq;
80                 atomic_inc(&irda_rq_queue.num_pending);
81                 add_timer(timer);
82                 ret = 1;
83         }
84         return ret;
85 }
86
87 static void run_irda_queue(void)
88 {
89         unsigned long flags;
90         struct list_head *entry, *tmp;
91         struct irda_request *rq;
92
93         spin_lock_irqsave(&irda_rq_queue.lock, flags);
94         list_for_each_safe(entry, tmp, &irda_rq_queue.request_list) {
95                 rq = list_entry(entry, struct irda_request, lh_request);
96                 list_del_init(entry);
97                 spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
98
99                 clear_bit(0, &rq->pending);
100                 rq->func(rq->data);
101
102                 if (atomic_dec_and_test(&irda_rq_queue.num_pending))
103                         wake_up(&irda_rq_queue.done);
104
105                 spin_lock_irqsave(&irda_rq_queue.lock, flags);
106         }
107         spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
108 }               
109
110 static int irda_thread(void *startup)
111 {
112         DECLARE_WAITQUEUE(wait, current);
113
114         daemonize("kIrDAd");
115
116         irda_rq_queue.thread = current;
117
118         complete((struct completion *)startup);
119
120         while (irda_rq_queue.thread != NULL) {
121
122                 /* We use TASK_INTERRUPTIBLE, rather than
123                  * TASK_UNINTERRUPTIBLE.  Andrew Morton made this
124                  * change ; he told me that it is safe, because "signal
125                  * blocking is now handled in daemonize()", he added
126                  * that the problem is that "uninterruptible sleep
127                  * contributes to load average", making user worry.
128                  * Jean II */
129                 set_task_state(current, TASK_INTERRUPTIBLE);
130                 add_wait_queue(&irda_rq_queue.kick, &wait);
131                 if (list_empty(&irda_rq_queue.request_list))
132                         schedule();
133                 else
134                         __set_task_state(current, TASK_RUNNING);
135                 remove_wait_queue(&irda_rq_queue.kick, &wait);
136
137                 /* make swsusp happy with our thread */
138                 try_to_freeze();
139
140                 run_irda_queue();
141         }
142
143 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,35)
144         reparent_to_init();
145 #endif
146         complete_and_exit(&irda_rq_queue.exit, 0);
147         /* never reached */
148         return 0;
149 }
150
151
152 static void flush_irda_queue(void)
153 {
154         if (atomic_read(&irda_rq_queue.num_pending)) {
155
156                 DECLARE_WAITQUEUE(wait, current);
157
158                 if (!list_empty(&irda_rq_queue.request_list))
159                         run_irda_queue();
160
161                 set_task_state(current, TASK_UNINTERRUPTIBLE);
162                 add_wait_queue(&irda_rq_queue.done, &wait);
163                 if (atomic_read(&irda_rq_queue.num_pending))
164                         schedule();
165                 else
166                         __set_task_state(current, TASK_RUNNING);
167                 remove_wait_queue(&irda_rq_queue.done, &wait);
168         }
169 }
170
171 /* substate handler of the config-fsm to handle the cases where we want
172  * to wait for transmit completion before changing the port configuration
173  */
174
175 static int irda_tx_complete_fsm(struct sir_dev *dev)
176 {
177         struct sir_fsm *fsm = &dev->fsm;
178         unsigned next_state, delay;
179         unsigned bytes_left;
180
181         do {
182                 next_state = fsm->substate;     /* default: stay in current substate */
183                 delay = 0;
184
185                 switch(fsm->substate) {
186
187                 case SIRDEV_STATE_WAIT_XMIT:
188                         if (dev->drv->chars_in_buffer)
189                                 bytes_left = dev->drv->chars_in_buffer(dev);
190                         else
191                                 bytes_left = 0;
192                         if (!bytes_left) {
193                                 next_state = SIRDEV_STATE_WAIT_UNTIL_SENT;
194                                 break;
195                         }
196
197                         if (dev->speed > 115200)
198                                 delay = (bytes_left*8*10000) / (dev->speed/100);
199                         else if (dev->speed > 0)
200                                 delay = (bytes_left*10*10000) / (dev->speed/100);
201                         else
202                                 delay = 0;
203                         /* expected delay (usec) until remaining bytes are sent */
204                         if (delay < 100) {
205                                 udelay(delay);
206                                 delay = 0;
207                                 break;
208                         }
209                         /* sleep some longer delay (msec) */
210                         delay = (delay+999) / 1000;
211                         break;
212
213                 case SIRDEV_STATE_WAIT_UNTIL_SENT:
214                         /* block until underlaying hardware buffer are empty */
215                         if (dev->drv->wait_until_sent)
216                                 dev->drv->wait_until_sent(dev);
217                         next_state = SIRDEV_STATE_TX_DONE;
218                         break;
219
220                 case SIRDEV_STATE_TX_DONE:
221                         return 0;
222
223                 default:
224                         IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
225                         return -EINVAL;
226                 }
227                 fsm->substate = next_state;
228         } while (delay == 0);
229         return delay;
230 }
231
232 /*
233  * Function irda_config_fsm
234  *
235  * State machine to handle the configuration of the device (and attached dongle, if any).
236  * This handler is scheduled for execution in kIrDAd context, so we can sleep.
237  * however, kIrDAd is shared by all sir_dev devices so we better don't sleep there too
238  * long. Instead, for longer delays we start a timer to reschedule us later.
239  * On entry, fsm->sem is always locked and the netdev xmit queue stopped.
240  * Both must be unlocked/restarted on completion - but only on final exit.
241  */
242
243 static void irda_config_fsm(void *data)
244 {
245         struct sir_dev *dev = data;
246         struct sir_fsm *fsm = &dev->fsm;
247         int next_state;
248         int ret = -1;
249         unsigned delay;
250
251         IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies); 
252
253         do {
254                 IRDA_DEBUG(3, "%s - state=0x%04x / substate=0x%04x\n",
255                         __FUNCTION__, fsm->state, fsm->substate);
256
257                 next_state = fsm->state;
258                 delay = 0;
259
260                 switch(fsm->state) {
261
262                 case SIRDEV_STATE_DONGLE_OPEN:
263                         if (dev->dongle_drv != NULL) {
264                                 ret = sirdev_put_dongle(dev);
265                                 if (ret) {
266                                         fsm->result = -EINVAL;
267                                         next_state = SIRDEV_STATE_ERROR;
268                                         break;
269                                 }
270                         }
271
272                         /* Initialize dongle */
273                         ret = sirdev_get_dongle(dev, fsm->param);
274                         if (ret) {
275                                 fsm->result = ret;
276                                 next_state = SIRDEV_STATE_ERROR;
277                                 break;
278                         }
279
280                         /* Dongles are powered through the modem control lines which
281                          * were just set during open. Before resetting, let's wait for
282                          * the power to stabilize. This is what some dongle drivers did
283                          * in open before, while others didn't - should be safe anyway.
284                          */
285
286                         delay = 50;
287                         fsm->substate = SIRDEV_STATE_DONGLE_RESET;
288                         next_state = SIRDEV_STATE_DONGLE_RESET;
289
290                         fsm->param = 9600;
291
292                         break;
293
294                 case SIRDEV_STATE_DONGLE_CLOSE:
295                         /* shouldn't we just treat this as success=? */
296                         if (dev->dongle_drv == NULL) {
297                                 fsm->result = -EINVAL;
298                                 next_state = SIRDEV_STATE_ERROR;
299                                 break;
300                         }
301
302                         ret = sirdev_put_dongle(dev);
303                         if (ret) {
304                                 fsm->result = ret;
305                                 next_state = SIRDEV_STATE_ERROR;
306                                 break;
307                         }
308                         next_state = SIRDEV_STATE_DONE;
309                         break;
310
311                 case SIRDEV_STATE_SET_DTR_RTS:
312                         ret = sirdev_set_dtr_rts(dev,
313                                 (fsm->param&0x02) ? TRUE : FALSE,
314                                 (fsm->param&0x01) ? TRUE : FALSE);
315                         next_state = SIRDEV_STATE_DONE;
316                         break;
317
318                 case SIRDEV_STATE_SET_SPEED:
319                         fsm->substate = SIRDEV_STATE_WAIT_XMIT;
320                         next_state = SIRDEV_STATE_DONGLE_CHECK;
321                         break;
322
323                 case SIRDEV_STATE_DONGLE_CHECK:
324                         ret = irda_tx_complete_fsm(dev);
325                         if (ret < 0) {
326                                 fsm->result = ret;
327                                 next_state = SIRDEV_STATE_ERROR;
328                                 break;
329                         }
330                         if ((delay=ret) != 0)
331                                 break;
332
333                         if (dev->dongle_drv) {
334                                 fsm->substate = SIRDEV_STATE_DONGLE_RESET;
335                                 next_state = SIRDEV_STATE_DONGLE_RESET;
336                         }
337                         else {
338                                 dev->speed = fsm->param;
339                                 next_state = SIRDEV_STATE_PORT_SPEED;
340                         }
341                         break;
342
343                 case SIRDEV_STATE_DONGLE_RESET:
344                         if (dev->dongle_drv->reset) {
345                                 ret = dev->dongle_drv->reset(dev);      
346                                 if (ret < 0) {
347                                         fsm->result = ret;
348                                         next_state = SIRDEV_STATE_ERROR;
349                                         break;
350                                 }
351                         }
352                         else
353                                 ret = 0;
354                         if ((delay=ret) == 0) {
355                                 /* set serial port according to dongle default speed */
356                                 if (dev->drv->set_speed)
357                                         dev->drv->set_speed(dev, dev->speed);
358                                 fsm->substate = SIRDEV_STATE_DONGLE_SPEED;
359                                 next_state = SIRDEV_STATE_DONGLE_SPEED;
360                         }
361                         break;
362
363                 case SIRDEV_STATE_DONGLE_SPEED:                         
364                         if (dev->dongle_drv->reset) {
365                                 ret = dev->dongle_drv->set_speed(dev, fsm->param);
366                                 if (ret < 0) {
367                                         fsm->result = ret;
368                                         next_state = SIRDEV_STATE_ERROR;
369                                         break;
370                                 }
371                         }
372                         else
373                                 ret = 0;
374                         if ((delay=ret) == 0)
375                                 next_state = SIRDEV_STATE_PORT_SPEED;
376                         break;
377
378                 case SIRDEV_STATE_PORT_SPEED:
379                         /* Finally we are ready to change the serial port speed */
380                         if (dev->drv->set_speed)
381                                 dev->drv->set_speed(dev, dev->speed);
382                         dev->new_speed = 0;
383                         next_state = SIRDEV_STATE_DONE;
384                         break;
385
386                 case SIRDEV_STATE_DONE:
387                         /* Signal network layer so it can send more frames */
388                         netif_wake_queue(dev->netdev);
389                         next_state = SIRDEV_STATE_COMPLETE;
390                         break;
391
392                 default:
393                         IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
394                         fsm->result = -EINVAL;
395                         /* fall thru */
396
397                 case SIRDEV_STATE_ERROR:
398                         IRDA_ERROR("%s - error: %d\n", __FUNCTION__, fsm->result);
399
400 #if 0   /* don't enable this before we have netdev->tx_timeout to recover */
401                         netif_stop_queue(dev->netdev);
402 #else
403                         netif_wake_queue(dev->netdev);
404 #endif
405                         /* fall thru */
406
407                 case SIRDEV_STATE_COMPLETE:
408                         /* config change finished, so we are not busy any longer */
409                         sirdev_enable_rx(dev);
410                         up(&fsm->sem);
411                         return;
412                 }
413                 fsm->state = next_state;
414         } while(!delay);
415
416         irda_queue_delayed_request(&fsm->rq, msecs_to_jiffies(delay));
417 }
418
419 /* schedule some device configuration task for execution by kIrDAd
420  * on behalf of the above state machine.
421  * can be called from process or interrupt/tasklet context.
422  */
423
424 int sirdev_schedule_request(struct sir_dev *dev, int initial_state, unsigned param)
425 {
426         struct sir_fsm *fsm = &dev->fsm;
427         int xmit_was_down;
428
429         IRDA_DEBUG(2, "%s - state=0x%04x / param=%u\n", __FUNCTION__, initial_state, param);
430
431         if (down_trylock(&fsm->sem)) {
432                 if (in_interrupt()  ||  in_atomic()  ||  irqs_disabled()) {
433                         IRDA_DEBUG(1, "%s(), state machine busy!\n", __FUNCTION__);
434                         return -EWOULDBLOCK;
435                 } else
436                         down(&fsm->sem);
437         }
438
439         if (fsm->state == SIRDEV_STATE_DEAD) {
440                 /* race with sirdev_close should never happen */
441                 IRDA_ERROR("%s(), instance staled!\n", __FUNCTION__);
442                 up(&fsm->sem);
443                 return -ESTALE;         /* or better EPIPE? */
444         }
445
446         xmit_was_down = netif_queue_stopped(dev->netdev);
447         netif_stop_queue(dev->netdev);
448         atomic_set(&dev->enable_rx, 0);
449
450         fsm->state = initial_state;
451         fsm->param = param;
452         fsm->result = 0;
453
454         INIT_LIST_HEAD(&fsm->rq.lh_request);
455         fsm->rq.pending = 0;
456         fsm->rq.func = irda_config_fsm;
457         fsm->rq.data = dev;
458
459         if (!irda_queue_request(&fsm->rq)) {    /* returns 0 on error! */
460                 atomic_set(&dev->enable_rx, 1);
461                 if (!xmit_was_down)
462                         netif_wake_queue(dev->netdev);          
463                 up(&fsm->sem);
464                 return -EAGAIN;
465         }
466         return 0;
467 }
468
469 int __init irda_thread_create(void)
470 {
471         struct completion startup;
472         int pid;
473
474         spin_lock_init(&irda_rq_queue.lock);
475         irda_rq_queue.thread = NULL;
476         INIT_LIST_HEAD(&irda_rq_queue.request_list);
477         init_waitqueue_head(&irda_rq_queue.kick);
478         init_waitqueue_head(&irda_rq_queue.done);
479         atomic_set(&irda_rq_queue.num_pending, 0);
480
481         init_completion(&startup);
482         pid = kernel_thread(irda_thread, &startup, CLONE_FS|CLONE_FILES);
483         if (pid <= 0)
484                 return -EAGAIN;
485         else
486                 wait_for_completion(&startup);
487
488         return 0;
489 }
490
491 void __exit irda_thread_join(void) 
492 {
493         if (irda_rq_queue.thread) {
494                 flush_irda_queue();
495                 init_completion(&irda_rq_queue.exit);
496                 irda_rq_queue.thread = NULL;
497                 wake_up(&irda_rq_queue.kick);           
498                 wait_for_completion(&irda_rq_queue.exit);
499         }
500 }
501