1/*
   2 * Parallel-port resource manager code.
   3 *
   4 * Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
   5 *          Tim Waugh <tim@cyberelk.demon.co.uk>
   6 *          Jose Renau <renau@acm.org>
   7 *          Philip Blundell <philb@gnu.org>
   8 *	    Andrea Arcangeli
   9 *
  10 * based on work by Grant Guenther <grant@torque.net>
  11 *          and Philip Blundell
  12 *
  13 * Any part of this program may be used in documents licensed under
  14 * the GNU Free Documentation License, Version 1.1 or any later version
  15 * published by the Free Software Foundation.
  16 */
  17
  18#undef PARPORT_DEBUG_SHARING		/* undef for production */
  19
  20#include <linux/module.h>
  21#include <linux/string.h>
  22#include <linux/threads.h>
  23#include <linux/parport.h>
  24#include <linux/delay.h>
  25#include <linux/errno.h>
  26#include <linux/interrupt.h>
  27#include <linux/ioport.h>
  28#include <linux/kernel.h>
  29#include <linux/slab.h>
  30#include <linux/sched/signal.h>
  31#include <linux/kmod.h>
  32#include <linux/device.h>
  33
  34#include <linux/spinlock.h>
  35#include <linux/mutex.h>
  36#include <asm/irq.h>
  37
  38#undef PARPORT_PARANOID
  39
  40#define PARPORT_DEFAULT_TIMESLICE	(HZ/5)
  41
  42unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
  43int parport_default_spintime =  DEFAULT_SPIN_TIME;
  44
  45static LIST_HEAD(portlist);
  46static DEFINE_SPINLOCK(parportlist_lock);
  47
  48/* list of all allocated ports, sorted by ->number */
  49static LIST_HEAD(all_ports);
  50static DEFINE_SPINLOCK(full_list_lock);
  51
  52static LIST_HEAD(drivers);
  53
  54static DEFINE_MUTEX(registration_lock);
  55
  56/* What you can do to a port that's gone away.. */
  57static void dead_write_lines(struct parport *p, unsigned char b){}
  58static unsigned char dead_read_lines(struct parport *p) { return 0; }
  59static unsigned char dead_frob_lines(struct parport *p, unsigned char b,
  60			     unsigned char c) { return 0; }
  61static void dead_onearg(struct parport *p){}
  62static void dead_initstate(struct pardevice *d, struct parport_state *s) { }
  63static void dead_state(struct parport *p, struct parport_state *s) { }
  64static size_t dead_write(struct parport *p, const void *b, size_t l, int f)
  65{ return 0; }
  66static size_t dead_read(struct parport *p, void *b, size_t l, int f)
  67{ return 0; }
  68static struct parport_operations dead_ops = {
  69	.write_data	= dead_write_lines,	/* data */
  70	.read_data	= dead_read_lines,
  71
  72	.write_control	= dead_write_lines,	/* control */
  73	.read_control	= dead_read_lines,
  74	.frob_control	= dead_frob_lines,
  75
  76	.read_status	= dead_read_lines,	/* status */
  77
  78	.enable_irq	= dead_onearg,		/* enable_irq */
  79	.disable_irq	= dead_onearg,		/* disable_irq */
  80
  81	.data_forward	= dead_onearg,		/* data_forward */
  82	.data_reverse	= dead_onearg,		/* data_reverse */
  83
  84	.init_state	= dead_initstate,	/* init_state */
  85	.save_state	= dead_state,
  86	.restore_state	= dead_state,
  87
  88	.epp_write_data	= dead_write,		/* epp */
  89	.epp_read_data	= dead_read,
  90	.epp_write_addr	= dead_write,
  91	.epp_read_addr	= dead_read,
  92
  93	.ecp_write_data	= dead_write,		/* ecp */
  94	.ecp_read_data	= dead_read,
  95	.ecp_write_addr	= dead_write,
  96
  97	.compat_write_data	= dead_write,	/* compat */
  98	.nibble_read_data	= dead_read,	/* nibble */
  99	.byte_read_data		= dead_read,	/* byte */
 100
 101	.owner		= NULL,
 102};
 103
 104static struct device_type parport_device_type = {
 105	.name = "parport",
 106};
 107
 108static int is_parport(struct device *dev)
 109{
 110	return dev->type == &parport_device_type;
 111}
 112
 113static int parport_probe(struct device *dev)
 114{
 115	struct parport_driver *drv;
 116
 117	if (is_parport(dev))
 118		return -ENODEV;
 119
 120	drv = to_parport_driver(dev->driver);
 121	if (!drv->probe) {
 122		/* if driver has not defined a custom probe */
 123		struct pardevice *par_dev = to_pardevice(dev);
 124
 125		if (strcmp(par_dev->name, drv->name))
 126			return -ENODEV;
 127		return 0;
 128	}
 129	/* if driver defined its own probe */
 130	return drv->probe(to_pardevice(dev));
 131}
 132
 133static struct bus_type parport_bus_type = {
 134	.name = "parport",
 135	.probe = parport_probe,
 136};
 137
 138int parport_bus_init(void)
 139{
 140	return bus_register(&parport_bus_type);
 141}
 142
 143void parport_bus_exit(void)
 144{
 145	bus_unregister(&parport_bus_type);
 146}
 147
 148/*
 149 * iterates through all the drivers registered with the bus and sends the port
 150 * details to the match_port callback of the driver, so that the driver can
 151 * know about the new port that just registered with the bus and decide if it
 152 * wants to use this new port.
 153 */
 154static int driver_check(struct device_driver *dev_drv, void *_port)
 155{
 156	struct parport *port = _port;
 157	struct parport_driver *drv = to_parport_driver(dev_drv);
 158
 159	if (drv->match_port)
 160		drv->match_port(port);
 161	return 0;
 162}
 163
 164/* Call attach(port) for each registered driver. */
 165static void attach_driver_chain(struct parport *port)
 166{
 167	/* caller has exclusive registration_lock */
 168	struct parport_driver *drv;
 169
 170	list_for_each_entry(drv, &drivers, list)
 171		drv->attach(port);
 172
 173	/*
 174	 * call the driver_check function of the drivers registered in
 175	 * new device model
 176	 */
 177
 178	bus_for_each_drv(&parport_bus_type, NULL, port, driver_check);
 179}
 180
 181static int driver_detach(struct device_driver *_drv, void *_port)
 182{
 183	struct parport *port = _port;
 184	struct parport_driver *drv = to_parport_driver(_drv);
 185
 186	if (drv->detach)
 187		drv->detach(port);
 188	return 0;
 189}
 190
 191/* Call detach(port) for each registered driver. */
 192static void detach_driver_chain(struct parport *port)
 193{
 194	struct parport_driver *drv;
 195	/* caller has exclusive registration_lock */
 196	list_for_each_entry(drv, &drivers, list)
 197		drv->detach(port);
 198
 199	/*
 200	 * call the detach function of the drivers registered in
 201	 * new device model
 202	 */
 203
 204	bus_for_each_drv(&parport_bus_type, NULL, port, driver_detach);
 205}
 206
 207/* Ask kmod for some lowlevel drivers. */
 208static void get_lowlevel_driver(void)
 209{
 210	/*
 211	 * There is no actual module called this: you should set
 212	 * up an alias for modutils.
 213	 */
 214	request_module("parport_lowlevel");
 215}
 216
 217/*
 218 * iterates through all the devices connected to the bus and sends the device
 219 * details to the match_port callback of the driver, so that the driver can
 220 * know what are all the ports that are connected to the bus and choose the
 221 * port to which it wants to register its device.
 222 */
 223static int port_check(struct device *dev, void *dev_drv)
 224{
 225	struct parport_driver *drv = dev_drv;
 226
 227	/* only send ports, do not send other devices connected to bus */
 228	if (is_parport(dev))
 229		drv->match_port(to_parport_dev(dev));
 230	return 0;
 231}
 232
 233/*
 234 * Iterates through all the devices connected to the bus and return 1
 235 * if the device is a parallel port.
 236 */
 237
 238static int port_detect(struct device *dev, void *dev_drv)
 239{
 240	if (is_parport(dev))
 241		return 1;
 242	return 0;
 243}
 244
 245/**
 246 *	__parport_register_driver - register a parallel port device driver
 247 *	@drv: structure describing the driver
 248 *	@owner: owner module of drv
 249 *	@mod_name: module name string
 250 *
 251 *	This can be called by a parallel port device driver in order
 252 *	to receive notifications about ports being found in the
 253 *	system, as well as ports no longer available.
 254 *
 255 *	If devmodel is true then the new device model is used
 256 *	for registration.
 257 *
 258 *	The @drv structure is allocated by the caller and must not be
 259 *	deallocated until after calling parport_unregister_driver().
 260 *
 261 *	If using the non device model:
 262 *	The driver's attach() function may block.  The port that
 263 *	attach() is given will be valid for the duration of the
 264 *	callback, but if the driver wants to take a copy of the
 265 *	pointer it must call parport_get_port() to do so.  Calling
 266 *	parport_register_device() on that port will do this for you.
 267 *
 268 *	The driver's detach() function may block.  The port that
 269 *	detach() is given will be valid for the duration of the
 270 *	callback, but if the driver wants to take a copy of the
 271 *	pointer it must call parport_get_port() to do so.
 272 *
 273 *
 274 *	Returns 0 on success. The non device model will always succeeds.
 275 *	but the new device model can fail and will return the error code.
 276 **/
 277
 278int __parport_register_driver(struct parport_driver *drv, struct module *owner,
 279			      const char *mod_name)
 280{
 281	/* using device model */
 282	int ret;
 283
 284	/* initialize common driver fields */
 285	drv->driver.name = drv->name;
 286	drv->driver.bus = &parport_bus_type;
 287	drv->driver.owner = owner;
 288	drv->driver.mod_name = mod_name;
 289	ret = driver_register(&drv->driver);
 290	if (ret)
 291		return ret;
 292
 293	/*
 294	 * check if bus has any parallel port registered, if
 295	 * none is found then load the lowlevel driver.
 296	 */
 297	ret = bus_for_each_dev(&parport_bus_type, NULL, NULL,
 298			       port_detect);
 299	if (!ret)
 300		get_lowlevel_driver();
 301
 302	mutex_lock(&registration_lock);
 303	if (drv->match_port)
 304		bus_for_each_dev(&parport_bus_type, NULL, drv,
 305				 port_check);
 306	mutex_unlock(&registration_lock);
 307
 308	return 0;
 309}
 310EXPORT_SYMBOL(__parport_register_driver);
 311
 312static int port_detach(struct device *dev, void *_drv)
 313{
 314	struct parport_driver *drv = _drv;
 315
 316	if (is_parport(dev) && drv->detach)
 317		drv->detach(to_parport_dev(dev));
 318
 319	return 0;
 320}
 321
 322/**
 323 *	parport_unregister_driver - deregister a parallel port device driver
 324 *	@drv: structure describing the driver that was given to
 325 *	      parport_register_driver()
 326 *
 327 *	This should be called by a parallel port device driver that
 328 *	has registered itself using parport_register_driver() when it
 329 *	is about to be unloaded.
 330 *
 331 *	When it returns, the driver's attach() routine will no longer
 332 *	be called, and for each port that attach() was called for, the
 333 *	detach() routine will have been called.
 334 *
 335 *	All the driver's attach() and detach() calls are guaranteed to have
 336 *	finished by the time this function returns.
 337 **/
 338
 339void parport_unregister_driver(struct parport_driver *drv)
 340{
 341	mutex_lock(&registration_lock);
 342	bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
 343	driver_unregister(&drv->driver);
 344	mutex_unlock(&registration_lock);
 345}
 346EXPORT_SYMBOL(parport_unregister_driver);
 347
 348static void free_port(struct device *dev)
 349{
 350	int d;
 351	struct parport *port = to_parport_dev(dev);
 352
 353	spin_lock(&full_list_lock);
 354	list_del(&port->full_list);
 355	spin_unlock(&full_list_lock);
 356	for (d = 0; d < 5; d++) {
 357		kfree(port->probe_info[d].class_name);
 358		kfree(port->probe_info[d].mfr);
 359		kfree(port->probe_info[d].model);
 360		kfree(port->probe_info[d].cmdset);
 361		kfree(port->probe_info[d].description);
 362	}
 363
 
 364	kfree(port);
 365}
 366
 367/**
 368 *	parport_get_port - increment a port's reference count
 369 *	@port: the port
 370 *
 371 *	This ensures that a struct parport pointer remains valid
 372 *	until the matching parport_put_port() call.
 373 **/
 374
 375struct parport *parport_get_port(struct parport *port)
 376{
 377	struct device *dev = get_device(&port->bus_dev);
 378
 379	return to_parport_dev(dev);
 380}
 381EXPORT_SYMBOL(parport_get_port);
 382
 383void parport_del_port(struct parport *port)
 384{
 385	device_unregister(&port->bus_dev);
 386}
 387EXPORT_SYMBOL(parport_del_port);
 388
 389/**
 390 *	parport_put_port - decrement a port's reference count
 391 *	@port: the port
 392 *
 393 *	This should be called once for each call to parport_get_port(),
 394 *	once the port is no longer needed. When the reference count reaches
 395 *	zero (port is no longer used), free_port is called.
 396 **/
 397
 398void parport_put_port(struct parport *port)
 399{
 400	put_device(&port->bus_dev);
 401}
 402EXPORT_SYMBOL(parport_put_port);
 403
 404/**
 405 *	parport_register_port - register a parallel port
 406 *	@base: base I/O address
 407 *	@irq: IRQ line
 408 *	@dma: DMA channel
 409 *	@ops: pointer to the port driver's port operations structure
 410 *
 411 *	When a parallel port (lowlevel) driver finds a port that
 412 *	should be made available to parallel port device drivers, it
 413 *	should call parport_register_port().  The @base, @irq, and
 414 *	@dma parameters are for the convenience of port drivers, and
 415 *	for ports where they aren't meaningful needn't be set to
 416 *	anything special.  They can be altered afterwards by adjusting
 417 *	the relevant members of the parport structure that is returned
 418 *	and represents the port.  They should not be tampered with
 419 *	after calling parport_announce_port, however.
 420 *
 421 *	If there are parallel port device drivers in the system that
 422 *	have registered themselves using parport_register_driver(),
 423 *	they are not told about the port at this time; that is done by
 424 *	parport_announce_port().
 425 *
 426 *	The @ops structure is allocated by the caller, and must not be
 427 *	deallocated before calling parport_remove_port().
 428 *
 429 *	If there is no memory to allocate a new parport structure,
 430 *	this function will return %NULL.
 431 **/
 432
 433struct parport *parport_register_port(unsigned long base, int irq, int dma,
 434				      struct parport_operations *ops)
 435{
 436	struct list_head *l;
 437	struct parport *tmp;
 438	int num;
 439	int device;
 
 440	int ret;
 441
 442	tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
 443	if (!tmp)
 444		return NULL;
 445
 446	/* Init our structure */
 447	tmp->base = base;
 448	tmp->irq = irq;
 449	tmp->dma = dma;
 450	tmp->muxport = tmp->daisy = tmp->muxsel = -1;
 
 451	INIT_LIST_HEAD(&tmp->list);
 
 
 452	tmp->ops = ops;
 453	tmp->physport = tmp;
 
 454	rwlock_init(&tmp->cad_lock);
 455	spin_lock_init(&tmp->waitlist_lock);
 456	spin_lock_init(&tmp->pardevice_lock);
 457	tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
 458	tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 459	sema_init(&tmp->ieee1284.irq, 0);
 460	tmp->spintime = parport_default_spintime;
 461	atomic_set(&tmp->ref_count, 1);
 
 462
 
 
 
 
 
 463	/* Search for the lowest free parport number. */
 464
 465	spin_lock(&full_list_lock);
 466	num = 0;
 467	list_for_each(l, &all_ports) {
 468		struct parport *p = list_entry(l, struct parport, full_list);
 469
 470		if (p->number != num++)
 471			break;
 472	}
 473	tmp->portnum = tmp->number = num;
 474	list_add_tail(&tmp->full_list, l);
 475	spin_unlock(&full_list_lock);
 476
 477	/*
 478	 * Now that the portnum is known finish doing the Init.
 479	 */
 480	dev_set_name(&tmp->bus_dev, "parport%d", tmp->portnum);
 
 481	tmp->bus_dev.bus = &parport_bus_type;
 482	tmp->bus_dev.release = free_port;
 
 483	tmp->bus_dev.type = &parport_device_type;
 484
 485	tmp->name = dev_name(&tmp->bus_dev);
 486
 487	for (device = 0; device < 5; device++)
 488		/* assume the worst */
 489		tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
 490
 
 
 491	ret = device_register(&tmp->bus_dev);
 492	if (ret) {
 493		put_device(&tmp->bus_dev);
 494		return NULL;
 495	}
 496
 497	return tmp;
 498}
 499EXPORT_SYMBOL(parport_register_port);
 500
 501/**
 502 *	parport_announce_port - tell device drivers about a parallel port
 503 *	@port: parallel port to announce
 504 *
 505 *	After a port driver has registered a parallel port with
 506 *	parport_register_port, and performed any necessary
 507 *	initialisation or adjustments, it should call
 508 *	parport_announce_port() in order to notify all device drivers
 509 *	that have called parport_register_driver().  Their attach()
 510 *	functions will be called, with @port as the parameter.
 511 **/
 512
 513void parport_announce_port(struct parport *port)
 514{
 515	int i;
 516
 517#ifdef CONFIG_PARPORT_1284
 518	/* Analyse the IEEE1284.3 topology of the port. */
 519	parport_daisy_init(port);
 520#endif
 521
 522	if (!port->dev)
 523		pr_warn("%s: fix this legacy no-device port driver!\n",
 524			port->name);
 525
 526	parport_proc_register(port);
 527	mutex_lock(&registration_lock);
 528	spin_lock_irq(&parportlist_lock);
 529	list_add_tail(&port->list, &portlist);
 530	for (i = 1; i < 3; i++) {
 531		struct parport *slave = port->slaves[i-1];
 532		if (slave)
 533			list_add_tail(&slave->list, &portlist);
 534	}
 535	spin_unlock_irq(&parportlist_lock);
 536
 537	/* Let drivers know that new port(s) has arrived. */
 538	attach_driver_chain(port);
 539	for (i = 1; i < 3; i++) {
 540		struct parport *slave = port->slaves[i-1];
 541		if (slave)
 542			attach_driver_chain(slave);
 543	}
 544	mutex_unlock(&registration_lock);
 545}
 546EXPORT_SYMBOL(parport_announce_port);
 547
 548/**
 549 *	parport_remove_port - deregister a parallel port
 550 *	@port: parallel port to deregister
 551 *
 552 *	When a parallel port driver is forcibly unloaded, or a
 553 *	parallel port becomes inaccessible, the port driver must call
 554 *	this function in order to deal with device drivers that still
 555 *	want to use it.
 556 *
 557 *	The parport structure associated with the port has its
 558 *	operations structure replaced with one containing 'null'
 559 *	operations that return errors or just don't do anything.
 560 *
 561 *	Any drivers that have registered themselves using
 562 *	parport_register_driver() are notified that the port is no
 563 *	longer accessible by having their detach() routines called
 564 *	with @port as the parameter.
 565 **/
 566
 567void parport_remove_port(struct parport *port)
 568{
 569	int i;
 570
 571	mutex_lock(&registration_lock);
 572
 573	/* Spread the word. */
 574	detach_driver_chain(port);
 575
 576#ifdef CONFIG_PARPORT_1284
 577	/* Forget the IEEE1284.3 topology of the port. */
 578	parport_daisy_fini(port);
 579	for (i = 1; i < 3; i++) {
 580		struct parport *slave = port->slaves[i-1];
 581		if (!slave)
 582			continue;
 583		detach_driver_chain(slave);
 584		parport_daisy_fini(slave);
 585	}
 586#endif
 587
 588	port->ops = &dead_ops;
 589	spin_lock(&parportlist_lock);
 590	list_del_init(&port->list);
 591	for (i = 1; i < 3; i++) {
 592		struct parport *slave = port->slaves[i-1];
 593		if (slave)
 594			list_del_init(&slave->list);
 595	}
 596	spin_unlock(&parportlist_lock);
 597
 598	mutex_unlock(&registration_lock);
 599
 600	parport_proc_unregister(port);
 601
 602	for (i = 1; i < 3; i++) {
 603		struct parport *slave = port->slaves[i-1];
 604		if (slave)
 605			parport_put_port(slave);
 606	}
 607}
 608EXPORT_SYMBOL(parport_remove_port);
 609
 610static void free_pardevice(struct device *dev)
 611{
 612	struct pardevice *par_dev = to_pardevice(dev);
 613
 614	kfree_const(par_dev->name);
 615	kfree(par_dev);
 616}
 617
 618/**
 619 *	parport_register_dev_model - register a device on a parallel port
 620 *	@port: port to which the device is attached
 621 *	@name: a name to refer to the device
 622 *	@par_dev_cb: struct containing callbacks
 623 *	@id: device number to be given to the device
 624 *
 625 *	This function, called by parallel port device drivers,
 626 *	declares that a device is connected to a port, and tells the
 627 *	system all it needs to know.
 628 *
 629 *	The struct pardev_cb contains pointer to callbacks. preemption
 630 *	callback function, @preempt, is called when this device driver
 631 *	has claimed access to the port but another device driver wants
 632 *	to use it.  It is given, @private, as its parameter, and should
 633 *	return zero if it is willing for the system to release the port
 634 *	to another driver on its behalf. If it wants to keep control of
 635 *	the port it should return non-zero, and no action will be taken.
 636 *	It is good manners for the driver to try to release the port at
 637 *	the earliest opportunity after its preemption callback rejects a
 638 *	preemption attempt. Note that if a preemption callback is happy
 639 *	for preemption to go ahead, there is no need to release the
 640 *	port; it is done automatically. This function may not block, as
 641 *	it may be called from interrupt context. If the device driver
 642 *	does not support preemption, @preempt can be %NULL.
 643 *
 644 *	The wake-up ("kick") callback function, @wakeup, is called when
 645 *	the port is available to be claimed for exclusive access; that
 646 *	is, parport_claim() is guaranteed to succeed when called from
 647 *	inside the wake-up callback function.  If the driver wants to
 648 *	claim the port it should do so; otherwise, it need not take
 649 *	any action.  This function may not block, as it may be called
 650 *	from interrupt context.  If the device driver does not want to
 651 *	be explicitly invited to claim the port in this way, @wakeup can
 652 *	be %NULL.
 653 *
 654 *	The interrupt handler, @irq_func, is called when an interrupt
 655 *	arrives from the parallel port.  Note that if a device driver
 656 *	wants to use interrupts it should use parport_enable_irq(),
 657 *	and can also check the irq member of the parport structure
 658 *	representing the port.
 659 *
 660 *	The parallel port (lowlevel) driver is the one that has called
 661 *	request_irq() and whose interrupt handler is called first.
 662 *	This handler does whatever needs to be done to the hardware to
 663 *	acknowledge the interrupt (for PC-style ports there is nothing
 664 *	special to be done).  It then tells the IEEE 1284 code about
 665 *	the interrupt, which may involve reacting to an IEEE 1284
 666 *	event depending on the current IEEE 1284 phase.  After this,
 667 *	it calls @irq_func.  Needless to say, @irq_func will be called
 668 *	from interrupt context, and may not block.
 669 *
 670 *	The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
 671 *	so should only be used when sharing the port with other device
 672 *	drivers is impossible and would lead to incorrect behaviour.
 673 *	Use it sparingly!  Normally, @flags will be zero.
 674 *
 675 *	This function returns a pointer to a structure that represents
 676 *	the device on the port, or %NULL if there is not enough memory
 677 *	to allocate space for that structure.
 678 **/
 679
 680struct pardevice *
 681parport_register_dev_model(struct parport *port, const char *name,
 682			   const struct pardev_cb *par_dev_cb, int id)
 683{
 684	struct pardevice *par_dev;
 685	const char *devname;
 686	int ret;
 
 687
 688	if (port->physport->flags & PARPORT_FLAG_EXCL) {
 689		/* An exclusive device is registered. */
 690		pr_err("%s: no more devices allowed\n", port->name);
 691		return NULL;
 692	}
 693
 694	if (par_dev_cb->flags & PARPORT_DEV_LURK) {
 695		if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
 696			pr_info("%s: refused to register lurking device (%s) without callbacks\n",
 697				port->name, name);
 698			return NULL;
 699		}
 700	}
 701
 702	if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
 703		if (port->physport->devices) {
 704			/*
 705			 * If a device is already registered and this new
 706			 * device wants exclusive access, then no need to
 707			 * continue as we can not grant exclusive access to
 708			 * this device.
 709			 */
 710			pr_err("%s: cannot grant exclusive access for device %s\n",
 711			       port->name, name);
 712			return NULL;
 713		}
 714	}
 715
 716	if (!try_module_get(port->ops->owner))
 717		return NULL;
 718
 719	parport_get_port(port);
 720
 721	par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
 722	if (!par_dev)
 723		goto err_put_port;
 724
 725	par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
 726	if (!par_dev->state)
 727		goto err_put_par_dev;
 728
 729	devname = kstrdup_const(name, GFP_KERNEL);
 730	if (!devname)
 731		goto err_free_par_dev;
 732
 733	par_dev->name = devname;
 734	par_dev->port = port;
 735	par_dev->daisy = -1;
 736	par_dev->preempt = par_dev_cb->preempt;
 737	par_dev->wakeup = par_dev_cb->wakeup;
 738	par_dev->private = par_dev_cb->private;
 739	par_dev->flags = par_dev_cb->flags;
 740	par_dev->irq_func = par_dev_cb->irq_func;
 741	par_dev->waiting = 0;
 742	par_dev->timeout = 5 * HZ;
 743
 744	par_dev->dev.parent = &port->bus_dev;
 745	par_dev->dev.bus = &parport_bus_type;
 746	ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
 747	if (ret)
 748		goto err_free_devname;
 749	par_dev->dev.release = free_pardevice;
 750	par_dev->devmodel = true;
 751	ret = device_register(&par_dev->dev);
 752	if (ret) {
 753		kfree(par_dev->state);
 754		put_device(&par_dev->dev);
 755		goto err_put_port;
 756	}
 757
 758	/* Chain this onto the list */
 759	par_dev->prev = NULL;
 760	/*
 761	 * This function must not run from an irq handler so we don' t need
 762	 * to clear irq on the local CPU. -arca
 763	 */
 764	spin_lock(&port->physport->pardevice_lock);
 765
 766	if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
 767		if (port->physport->devices) {
 768			spin_unlock(&port->physport->pardevice_lock);
 769			pr_debug("%s: cannot grant exclusive access for device %s\n",
 770				 port->name, name);
 771			kfree(par_dev->state);
 772			device_unregister(&par_dev->dev);
 773			goto err_put_port;
 774		}
 775		port->flags |= PARPORT_FLAG_EXCL;
 776	}
 777
 778	par_dev->next = port->physport->devices;
 779	wmb();	/*
 780		 * Make sure that tmp->next is written before it's
 781		 * added to the list; see comments marked 'no locking
 782		 * required'
 783		 */
 784	if (port->physport->devices)
 785		port->physport->devices->prev = par_dev;
 786	port->physport->devices = par_dev;
 787	spin_unlock(&port->physport->pardevice_lock);
 788
 789	init_waitqueue_head(&par_dev->wait_q);
 790	par_dev->timeslice = parport_default_timeslice;
 791	par_dev->waitnext = NULL;
 792	par_dev->waitprev = NULL;
 793
 794	/*
 795	 * This has to be run as last thing since init_state may need other
 796	 * pardevice fields. -arca
 797	 */
 798	port->ops->init_state(par_dev, par_dev->state);
 799	if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
 800		port->proc_device = par_dev;
 801		parport_device_proc_register(par_dev);
 802	}
 803
 804	return par_dev;
 805
 806err_free_devname:
 807	kfree_const(devname);
 808err_free_par_dev:
 809	kfree(par_dev->state);
 810err_put_par_dev:
 811	if (!par_dev->devmodel)
 812		kfree(par_dev);
 813err_put_port:
 814	parport_put_port(port);
 815	module_put(port->ops->owner);
 816
 817	return NULL;
 818}
 819EXPORT_SYMBOL(parport_register_dev_model);
 820
 821/**
 822 *	parport_unregister_device - deregister a device on a parallel port
 823 *	@dev: pointer to structure representing device
 824 *
 825 *	This undoes the effect of parport_register_device().
 826 **/
 827
 828void parport_unregister_device(struct pardevice *dev)
 829{
 830	struct parport *port;
 831
 832#ifdef PARPORT_PARANOID
 833	if (!dev) {
 834		pr_err("%s: passed NULL\n", __func__);
 835		return;
 836	}
 837#endif
 838
 839	port = dev->port->physport;
 840
 841	if (port->proc_device == dev) {
 842		port->proc_device = NULL;
 843		clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
 844		parport_device_proc_unregister(dev);
 845	}
 846
 847	if (port->cad == dev) {
 848		printk(KERN_DEBUG "%s: %s forgot to release port\n",
 849		       port->name, dev->name);
 850		parport_release(dev);
 851	}
 852
 853	spin_lock(&port->pardevice_lock);
 854	if (dev->next)
 855		dev->next->prev = dev->prev;
 856	if (dev->prev)
 857		dev->prev->next = dev->next;
 858	else
 859		port->devices = dev->next;
 860
 861	if (dev->flags & PARPORT_DEV_EXCL)
 862		port->flags &= ~PARPORT_FLAG_EXCL;
 863
 864	spin_unlock(&port->pardevice_lock);
 865
 866	/*
 867	 * Make sure we haven't left any pointers around in the wait
 868	 * list.
 869	 */
 870	spin_lock_irq(&port->waitlist_lock);
 871	if (dev->waitprev || dev->waitnext || port->waithead == dev) {
 872		if (dev->waitprev)
 873			dev->waitprev->waitnext = dev->waitnext;
 874		else
 875			port->waithead = dev->waitnext;
 876		if (dev->waitnext)
 877			dev->waitnext->waitprev = dev->waitprev;
 878		else
 879			port->waittail = dev->waitprev;
 880	}
 881	spin_unlock_irq(&port->waitlist_lock);
 882
 883	kfree(dev->state);
 884	device_unregister(&dev->dev);
 885
 886	module_put(port->ops->owner);
 887	parport_put_port(port);
 888}
 889EXPORT_SYMBOL(parport_unregister_device);
 890
 891/**
 892 *	parport_find_number - find a parallel port by number
 893 *	@number: parallel port number
 894 *
 895 *	This returns the parallel port with the specified number, or
 896 *	%NULL if there is none.
 897 *
 898 *	There is an implicit parport_get_port() done already; to throw
 899 *	away the reference to the port that parport_find_number()
 900 *	gives you, use parport_put_port().
 901 */
 902
 903struct parport *parport_find_number(int number)
 904{
 905	struct parport *port, *result = NULL;
 906
 907	if (list_empty(&portlist))
 908		get_lowlevel_driver();
 909
 910	spin_lock(&parportlist_lock);
 911	list_for_each_entry(port, &portlist, list) {
 912		if (port->number == number) {
 913			result = parport_get_port(port);
 914			break;
 915		}
 916	}
 917	spin_unlock(&parportlist_lock);
 918	return result;
 919}
 920EXPORT_SYMBOL(parport_find_number);
 921
 922/**
 923 *	parport_find_base - find a parallel port by base address
 924 *	@base: base I/O address
 925 *
 926 *	This returns the parallel port with the specified base
 927 *	address, or %NULL if there is none.
 928 *
 929 *	There is an implicit parport_get_port() done already; to throw
 930 *	away the reference to the port that parport_find_base()
 931 *	gives you, use parport_put_port().
 932 */
 933
 934struct parport *parport_find_base(unsigned long base)
 935{
 936	struct parport *port, *result = NULL;
 937
 938	if (list_empty(&portlist))
 939		get_lowlevel_driver();
 940
 941	spin_lock(&parportlist_lock);
 942	list_for_each_entry(port, &portlist, list) {
 943		if (port->base == base) {
 944			result = parport_get_port(port);
 945			break;
 946		}
 947	}
 948	spin_unlock(&parportlist_lock);
 949	return result;
 950}
 951EXPORT_SYMBOL(parport_find_base);
 952
 953/**
 954 *	parport_claim - claim access to a parallel port device
 955 *	@dev: pointer to structure representing a device on the port
 956 *
 957 *	This function will not block and so can be used from interrupt
 958 *	context.  If parport_claim() succeeds in claiming access to
 959 *	the port it returns zero and the port is available to use.  It
 960 *	may fail (returning non-zero) if the port is in use by another
 961 *	driver and that driver is not willing to relinquish control of
 962 *	the port.
 963 **/
 964
 965int parport_claim(struct pardevice *dev)
 966{
 967	struct pardevice *oldcad;
 968	struct parport *port = dev->port->physport;
 969	unsigned long flags;
 970
 971	if (port->cad == dev) {
 972		pr_info("%s: %s already owner\n", dev->port->name, dev->name);
 973		return 0;
 974	}
 975
 976	/* Preempt any current device */
 977	write_lock_irqsave(&port->cad_lock, flags);
 978	oldcad = port->cad;
 979	if (oldcad) {
 980		if (oldcad->preempt) {
 981			if (oldcad->preempt(oldcad->private))
 982				goto blocked;
 983			port->ops->save_state(port, dev->state);
 984		} else
 985			goto blocked;
 986
 987		if (port->cad != oldcad) {
 988			/*
 989			 * I think we'll actually deadlock rather than
 990			 * get here, but just in case..
 991			 */
 992			pr_warn("%s: %s released port when preempted!\n",
 993				port->name, oldcad->name);
 994			if (port->cad)
 995				goto blocked;
 996		}
 997	}
 998
 999	/* Can't fail from now on, so mark ourselves as no longer waiting.  */
1000	if (dev->waiting & 1) {
1001		dev->waiting = 0;
1002
1003		/* Take ourselves out of the wait list again.  */
1004		spin_lock_irq(&port->waitlist_lock);
1005		if (dev->waitprev)
1006			dev->waitprev->waitnext = dev->waitnext;
1007		else
1008			port->waithead = dev->waitnext;
1009		if (dev->waitnext)
1010			dev->waitnext->waitprev = dev->waitprev;
1011		else
1012			port->waittail = dev->waitprev;
1013		spin_unlock_irq(&port->waitlist_lock);
1014		dev->waitprev = dev->waitnext = NULL;
1015	}
1016
1017	/* Now we do the change of devices */
1018	port->cad = dev;
1019
1020#ifdef CONFIG_PARPORT_1284
1021	/* If it's a mux port, select it. */
1022	if (dev->port->muxport >= 0) {
1023		/* FIXME */
1024		port->muxsel = dev->port->muxport;
1025	}
1026
1027	/* If it's a daisy chain device, select it. */
1028	if (dev->daisy >= 0) {
1029		/* This could be lazier. */
1030		if (!parport_daisy_select(port, dev->daisy,
1031					   IEEE1284_MODE_COMPAT))
1032			port->daisy = dev->daisy;
1033	}
1034#endif /* IEEE1284.3 support */
1035
1036	/* Restore control registers */
1037	port->ops->restore_state(port, dev->state);
1038	write_unlock_irqrestore(&port->cad_lock, flags);
1039	dev->time = jiffies;
1040	return 0;
1041
1042blocked:
1043	/*
1044	 * If this is the first time we tried to claim the port, register an
1045	 * interest.  This is only allowed for devices sleeping in
1046	 * parport_claim_or_block(), or those with a wakeup function.
1047	 */
1048
1049	/* The cad_lock is still held for writing here */
1050	if (dev->waiting & 2 || dev->wakeup) {
1051		spin_lock(&port->waitlist_lock);
1052		if (test_and_set_bit(0, &dev->waiting) == 0) {
1053			/* First add ourselves to the end of the wait list. */
1054			dev->waitnext = NULL;
1055			dev->waitprev = port->waittail;
1056			if (port->waittail) {
1057				port->waittail->waitnext = dev;
1058				port->waittail = dev;
1059			} else
1060				port->waithead = port->waittail = dev;
1061		}
1062		spin_unlock(&port->waitlist_lock);
1063	}
1064	write_unlock_irqrestore(&port->cad_lock, flags);
1065	return -EAGAIN;
1066}
1067EXPORT_SYMBOL(parport_claim);
1068
1069/**
1070 *	parport_claim_or_block - claim access to a parallel port device
1071 *	@dev: pointer to structure representing a device on the port
1072 *
1073 *	This behaves like parport_claim(), but will block if necessary
1074 *	to wait for the port to be free.  A return value of 1
1075 *	indicates that it slept; 0 means that it succeeded without
1076 *	needing to sleep.  A negative error code indicates failure.
1077 **/
1078
1079int parport_claim_or_block(struct pardevice *dev)
1080{
1081	int r;
1082
1083	/*
1084	 * Signal to parport_claim() that we can wait even without a
1085	 * wakeup function.
1086	 */
1087	dev->waiting = 2;
1088
1089	/* Try to claim the port.  If this fails, we need to sleep.  */
1090	r = parport_claim(dev);
1091	if (r == -EAGAIN) {
1092#ifdef PARPORT_DEBUG_SHARING
1093		printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n",
1094		       dev->name);
1095#endif
1096		/*
1097		 * FIXME!!! Use the proper locking for dev->waiting,
1098		 * and make this use the "wait_event_interruptible()"
1099		 * interfaces. The cli/sti that used to be here
1100		 * did nothing.
1101		 *
1102		 * See also parport_release()
1103		 */
1104
1105		/*
1106		 * If dev->waiting is clear now, an interrupt
1107		 * gave us the port and we would deadlock if we slept.
1108		 */
1109		if (dev->waiting) {
1110			wait_event_interruptible(dev->wait_q,
1111						 !dev->waiting);
1112			if (signal_pending(current))
1113				return -EINTR;
1114			r = 1;
1115		} else {
1116			r = 0;
1117#ifdef PARPORT_DEBUG_SHARING
1118			printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1119			       dev->name);
1120#endif
1121		}
1122
1123#ifdef PARPORT_DEBUG_SHARING
1124		if (dev->port->physport->cad != dev)
1125			printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1126			       dev->name, dev->port->physport->cad ?
1127			       dev->port->physport->cad->name : "nobody");
1128#endif
1129	}
1130	dev->waiting = 0;
1131	return r;
1132}
1133EXPORT_SYMBOL(parport_claim_or_block);
1134
1135/**
1136 *	parport_release - give up access to a parallel port device
1137 *	@dev: pointer to structure representing parallel port device
1138 *
1139 *	This function cannot fail, but it should not be called without
1140 *	the port claimed.  Similarly, if the port is already claimed
1141 *	you should not try claiming it again.
1142 **/
1143
1144void parport_release(struct pardevice *dev)
1145{
1146	struct parport *port = dev->port->physport;
1147	struct pardevice *pd;
1148	unsigned long flags;
1149
1150	/* Make sure that dev is the current device */
1151	write_lock_irqsave(&port->cad_lock, flags);
1152	if (port->cad != dev) {
1153		write_unlock_irqrestore(&port->cad_lock, flags);
1154		pr_warn("%s: %s tried to release parport when not owner\n",
1155			port->name, dev->name);
1156		return;
1157	}
1158
1159#ifdef CONFIG_PARPORT_1284
1160	/* If this is on a mux port, deselect it. */
1161	if (dev->port->muxport >= 0) {
1162		/* FIXME */
1163		port->muxsel = -1;
1164	}
1165
1166	/* If this is a daisy device, deselect it. */
1167	if (dev->daisy >= 0) {
1168		parport_daisy_deselect_all(port);
1169		port->daisy = -1;
1170	}
1171#endif
1172
1173	port->cad = NULL;
1174	write_unlock_irqrestore(&port->cad_lock, flags);
1175
1176	/* Save control registers */
1177	port->ops->save_state(port, dev->state);
1178
1179	/*
1180	 * If anybody is waiting, find out who's been there longest and
1181	 * then wake them up. (Note: no locking required)
1182	 */
1183	/* !!! LOCKING IS NEEDED HERE */
1184	for (pd = port->waithead; pd; pd = pd->waitnext) {
1185		if (pd->waiting & 2) { /* sleeping in claim_or_block */
1186			parport_claim(pd);
1187			if (waitqueue_active(&pd->wait_q))
1188				wake_up_interruptible(&pd->wait_q);
1189			return;
1190		} else if (pd->wakeup) {
1191			pd->wakeup(pd->private);
1192			if (dev->port->cad) /* racy but no matter */
1193				return;
1194		} else {
1195			pr_err("%s: don't know how to wake %s\n",
1196			       port->name, pd->name);
1197		}
1198	}
1199
1200	/*
1201	 * Nobody was waiting, so walk the list to see if anyone is
1202	 * interested in being woken up. (Note: no locking required)
1203	 */
1204	/* !!! LOCKING IS NEEDED HERE */
1205	for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1206		if (pd->wakeup && pd != dev)
1207			pd->wakeup(pd->private);
1208	}
1209}
1210EXPORT_SYMBOL(parport_release);
1211
1212irqreturn_t parport_irq_handler(int irq, void *dev_id)
1213{
1214	struct parport *port = dev_id;
1215
1216	parport_generic_irq(port);
1217
1218	return IRQ_HANDLED;
1219}
1220EXPORT_SYMBOL(parport_irq_handler);
1221
1222MODULE_LICENSE("GPL");