Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 */ |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 138 | try_to_freeze(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |