2 * Parallel-port resource manager code.
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>
10 * based on work by Grant Guenther <grant@torque.net>
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.
18 #undef PARPORT_DEBUG_SHARING /* undef for production */
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.h>
31 #include <linux/kmod.h>
32 #include <linux/device.h>
34 #include <linux/spinlock.h>
35 #include <linux/mutex.h>
38 #undef PARPORT_PARANOID
40 #define PARPORT_DEFAULT_TIMESLICE (HZ/5)
42 unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
43 int parport_default_spintime = DEFAULT_SPIN_TIME;
45 static LIST_HEAD(portlist);
46 static DEFINE_SPINLOCK(parportlist_lock);
48 /* list of all allocated ports, sorted by ->number */
49 static LIST_HEAD(all_ports);
50 static DEFINE_SPINLOCK(full_list_lock);
52 static LIST_HEAD(drivers);
54 static DEFINE_MUTEX(registration_lock);
56 /* What you can do to a port that's gone away.. */
57 static void dead_write_lines (struct parport *p, unsigned char b){}
58 static unsigned char dead_read_lines (struct parport *p) { return 0; }
59 static unsigned char dead_frob_lines (struct parport *p, unsigned char b,
60 unsigned char c) { return 0; }
61 static void dead_onearg (struct parport *p){}
62 static void dead_initstate (struct pardevice *d, struct parport_state *s) { }
63 static void dead_state (struct parport *p, struct parport_state *s) { }
64 static size_t dead_write (struct parport *p, const void *b, size_t l, int f)
66 static size_t dead_read (struct parport *p, void *b, size_t l, int f)
68 static struct parport_operations dead_ops = {
69 .write_data = dead_write_lines, /* data */
70 .read_data = dead_read_lines,
72 .write_control = dead_write_lines, /* control */
73 .read_control = dead_read_lines,
74 .frob_control = dead_frob_lines,
76 .read_status = dead_read_lines, /* status */
78 .enable_irq = dead_onearg, /* enable_irq */
79 .disable_irq = dead_onearg, /* disable_irq */
81 .data_forward = dead_onearg, /* data_forward */
82 .data_reverse = dead_onearg, /* data_reverse */
84 .init_state = dead_initstate, /* init_state */
85 .save_state = dead_state,
86 .restore_state = dead_state,
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,
93 .ecp_write_data = dead_write, /* ecp */
94 .ecp_read_data = dead_read,
95 .ecp_write_addr = dead_write,
97 .compat_write_data = dead_write, /* compat */
98 .nibble_read_data = dead_read, /* nibble */
99 .byte_read_data = dead_read, /* byte */
104 static struct device_type parport_device_type = {
108 static int is_parport(struct device *dev)
110 return dev->type == &parport_device_type;
113 static int parport_probe(struct device *dev)
115 struct parport_driver *drv;
120 drv = to_parport_driver(dev->driver);
122 /* if driver has not defined a custom probe */
123 struct pardevice *par_dev = to_pardevice(dev);
125 if (strcmp(par_dev->name, drv->name))
129 /* if driver defined its own probe */
130 return drv->probe(to_pardevice(dev));
133 static struct bus_type parport_bus_type = {
135 .probe = parport_probe,
138 int parport_bus_init(void)
140 return bus_register(&parport_bus_type);
143 void parport_bus_exit(void)
145 bus_unregister(&parport_bus_type);
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.
154 static int driver_check(struct device_driver *dev_drv, void *_port)
156 struct parport *port = _port;
157 struct parport_driver *drv = to_parport_driver(dev_drv);
160 drv->match_port(port);
164 /* Call attach(port) for each registered driver. */
165 static void attach_driver_chain(struct parport *port)
167 /* caller has exclusive registration_lock */
168 struct parport_driver *drv;
170 list_for_each_entry(drv, &drivers, list)
174 * call the driver_check function of the drivers registered in
178 bus_for_each_drv(&parport_bus_type, NULL, port, driver_check);
181 static int driver_detach(struct device_driver *_drv, void *_port)
183 struct parport *port = _port;
184 struct parport_driver *drv = to_parport_driver(_drv);
191 /* Call detach(port) for each registered driver. */
192 static void detach_driver_chain(struct parport *port)
194 struct parport_driver *drv;
195 /* caller has exclusive registration_lock */
196 list_for_each_entry(drv, &drivers, list)
200 * call the detach function of the drivers registered in
204 bus_for_each_drv(&parport_bus_type, NULL, port, driver_detach);
207 /* Ask kmod for some lowlevel drivers. */
208 static void get_lowlevel_driver (void)
211 * There is no actual module called this: you should set
212 * up an alias for modutils.
214 request_module ("parport_lowlevel");
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.
223 static int port_check(struct device *dev, void *dev_drv)
225 struct parport_driver *drv = dev_drv;
227 /* only send ports, do not send other devices connected to bus */
229 drv->match_port(to_parport_dev(dev));
234 * parport_register_driver - register a parallel port device driver
235 * @drv: structure describing the driver
236 * @owner: owner module of drv
237 * @mod_name: module name string
239 * This can be called by a parallel port device driver in order
240 * to receive notifications about ports being found in the
241 * system, as well as ports no longer available.
243 * If devmodel is true then the new device model is used
246 * The @drv structure is allocated by the caller and must not be
247 * deallocated until after calling parport_unregister_driver().
249 * If using the non device model:
250 * The driver's attach() function may block. The port that
251 * attach() is given will be valid for the duration of the
252 * callback, but if the driver wants to take a copy of the
253 * pointer it must call parport_get_port() to do so. Calling
254 * parport_register_device() on that port will do this for you.
256 * The driver's detach() function may block. The port that
257 * detach() is given will be valid for the duration of the
258 * callback, but if the driver wants to take a copy of the
259 * pointer it must call parport_get_port() to do so.
262 * Returns 0 on success. The non device model will always succeeds.
263 * but the new device model can fail and will return the error code.
266 int __parport_register_driver(struct parport_driver *drv, struct module *owner,
267 const char *mod_name)
269 if (list_empty(&portlist))
270 get_lowlevel_driver ();
273 /* using device model */
276 /* initialize common driver fields */
277 drv->driver.name = drv->name;
278 drv->driver.bus = &parport_bus_type;
279 drv->driver.owner = owner;
280 drv->driver.mod_name = mod_name;
281 ret = driver_register(&drv->driver);
285 mutex_lock(®istration_lock);
287 bus_for_each_dev(&parport_bus_type, NULL, drv,
289 mutex_unlock(®istration_lock);
291 struct parport *port;
293 drv->devmodel = false;
295 mutex_lock(®istration_lock);
296 list_for_each_entry(port, &portlist, list)
298 list_add(&drv->list, &drivers);
299 mutex_unlock(®istration_lock);
304 EXPORT_SYMBOL(__parport_register_driver);
306 static int port_detach(struct device *dev, void *_drv)
308 struct parport_driver *drv = _drv;
310 if (is_parport(dev) && drv->detach)
311 drv->detach(to_parport_dev(dev));
317 * parport_unregister_driver - deregister a parallel port device driver
318 * @drv: structure describing the driver that was given to
319 * parport_register_driver()
321 * This should be called by a parallel port device driver that
322 * has registered itself using parport_register_driver() when it
323 * is about to be unloaded.
325 * When it returns, the driver's attach() routine will no longer
326 * be called, and for each port that attach() was called for, the
327 * detach() routine will have been called.
329 * All the driver's attach() and detach() calls are guaranteed to have
330 * finished by the time this function returns.
333 void parport_unregister_driver (struct parport_driver *drv)
335 struct parport *port;
337 mutex_lock(®istration_lock);
339 bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
340 driver_unregister(&drv->driver);
342 list_del_init(&drv->list);
343 list_for_each_entry(port, &portlist, list)
346 mutex_unlock(®istration_lock);
348 EXPORT_SYMBOL(parport_unregister_driver);
350 static void free_port(struct device *dev)
353 struct parport *port = to_parport_dev(dev);
355 spin_lock(&full_list_lock);
356 list_del(&port->full_list);
357 spin_unlock(&full_list_lock);
358 for (d = 0; d < 5; d++) {
359 kfree(port->probe_info[d].class_name);
360 kfree(port->probe_info[d].mfr);
361 kfree(port->probe_info[d].model);
362 kfree(port->probe_info[d].cmdset);
363 kfree(port->probe_info[d].description);
371 * parport_get_port - increment a port's reference count
374 * This ensures that a struct parport pointer remains valid
375 * until the matching parport_put_port() call.
378 struct parport *parport_get_port (struct parport *port)
380 struct device *dev = get_device(&port->bus_dev);
382 return to_parport_dev(dev);
384 EXPORT_SYMBOL(parport_get_port);
386 void parport_del_port(struct parport *port)
388 device_unregister(&port->bus_dev);
390 EXPORT_SYMBOL(parport_del_port);
393 * parport_put_port - decrement a port's reference count
396 * This should be called once for each call to parport_get_port(),
397 * once the port is no longer needed. When the reference count reaches
398 * zero (port is no longer used), free_port is called.
401 void parport_put_port (struct parport *port)
403 put_device(&port->bus_dev);
405 EXPORT_SYMBOL(parport_put_port);
408 * parport_register_port - register a parallel port
409 * @base: base I/O address
412 * @ops: pointer to the port driver's port operations structure
414 * When a parallel port (lowlevel) driver finds a port that
415 * should be made available to parallel port device drivers, it
416 * should call parport_register_port(). The @base, @irq, and
417 * @dma parameters are for the convenience of port drivers, and
418 * for ports where they aren't meaningful needn't be set to
419 * anything special. They can be altered afterwards by adjusting
420 * the relevant members of the parport structure that is returned
421 * and represents the port. They should not be tampered with
422 * after calling parport_announce_port, however.
424 * If there are parallel port device drivers in the system that
425 * have registered themselves using parport_register_driver(),
426 * they are not told about the port at this time; that is done by
427 * parport_announce_port().
429 * The @ops structure is allocated by the caller, and must not be
430 * deallocated before calling parport_remove_port().
432 * If there is no memory to allocate a new parport structure,
433 * this function will return %NULL.
436 struct parport *parport_register_port(unsigned long base, int irq, int dma,
437 struct parport_operations *ops)
446 tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
448 printk(KERN_WARNING "parport: memory squeeze\n");
452 /* Init our structure */
456 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
458 INIT_LIST_HEAD(&tmp->list);
459 tmp->devices = tmp->cad = NULL;
463 memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info));
464 rwlock_init(&tmp->cad_lock);
465 spin_lock_init(&tmp->waitlist_lock);
466 spin_lock_init(&tmp->pardevice_lock);
467 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
468 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
469 sema_init(&tmp->ieee1284.irq, 0);
470 tmp->spintime = parport_default_spintime;
471 atomic_set (&tmp->ref_count, 1);
472 INIT_LIST_HEAD(&tmp->full_list);
474 name = kmalloc(15, GFP_KERNEL);
476 printk(KERN_ERR "parport: memory squeeze\n");
480 /* Search for the lowest free parport number. */
482 spin_lock(&full_list_lock);
483 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
484 struct parport *p = list_entry(l, struct parport, full_list);
485 if (p->number != num)
488 tmp->portnum = tmp->number = num;
489 list_add_tail(&tmp->full_list, l);
490 spin_unlock(&full_list_lock);
493 * Now that the portnum is known finish doing the Init.
495 sprintf(name, "parport%d", tmp->portnum = tmp->number);
497 tmp->bus_dev.bus = &parport_bus_type;
498 tmp->bus_dev.release = free_port;
499 dev_set_name(&tmp->bus_dev, name);
500 tmp->bus_dev.type = &parport_device_type;
502 for (device = 0; device < 5; device++)
503 /* assume the worst */
504 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
506 tmp->waithead = tmp->waittail = NULL;
508 ret = device_register(&tmp->bus_dev);
510 put_device(&tmp->bus_dev);
516 EXPORT_SYMBOL(parport_register_port);
519 * parport_announce_port - tell device drivers about a parallel port
520 * @port: parallel port to announce
522 * After a port driver has registered a parallel port with
523 * parport_register_port, and performed any necessary
524 * initialisation or adjustments, it should call
525 * parport_announce_port() in order to notify all device drivers
526 * that have called parport_register_driver(). Their attach()
527 * functions will be called, with @port as the parameter.
530 void parport_announce_port (struct parport *port)
534 #ifdef CONFIG_PARPORT_1284
535 /* Analyse the IEEE1284.3 topology of the port. */
536 parport_daisy_init(port);
540 printk(KERN_WARNING "%s: fix this legacy no-device port driver!\n",
543 parport_proc_register(port);
544 mutex_lock(®istration_lock);
545 spin_lock_irq(&parportlist_lock);
546 list_add_tail(&port->list, &portlist);
547 for (i = 1; i < 3; i++) {
548 struct parport *slave = port->slaves[i-1];
550 list_add_tail(&slave->list, &portlist);
552 spin_unlock_irq(&parportlist_lock);
554 /* Let drivers know that new port(s) has arrived. */
555 attach_driver_chain (port);
556 for (i = 1; i < 3; i++) {
557 struct parport *slave = port->slaves[i-1];
559 attach_driver_chain(slave);
561 mutex_unlock(®istration_lock);
563 EXPORT_SYMBOL(parport_announce_port);
566 * parport_remove_port - deregister a parallel port
567 * @port: parallel port to deregister
569 * When a parallel port driver is forcibly unloaded, or a
570 * parallel port becomes inaccessible, the port driver must call
571 * this function in order to deal with device drivers that still
574 * The parport structure associated with the port has its
575 * operations structure replaced with one containing 'null'
576 * operations that return errors or just don't do anything.
578 * Any drivers that have registered themselves using
579 * parport_register_driver() are notified that the port is no
580 * longer accessible by having their detach() routines called
581 * with @port as the parameter.
584 void parport_remove_port(struct parport *port)
588 mutex_lock(®istration_lock);
590 /* Spread the word. */
591 detach_driver_chain (port);
593 #ifdef CONFIG_PARPORT_1284
594 /* Forget the IEEE1284.3 topology of the port. */
595 parport_daisy_fini(port);
596 for (i = 1; i < 3; i++) {
597 struct parport *slave = port->slaves[i-1];
600 detach_driver_chain(slave);
601 parport_daisy_fini(slave);
605 port->ops = &dead_ops;
606 spin_lock(&parportlist_lock);
607 list_del_init(&port->list);
608 for (i = 1; i < 3; i++) {
609 struct parport *slave = port->slaves[i-1];
611 list_del_init(&slave->list);
613 spin_unlock(&parportlist_lock);
615 mutex_unlock(®istration_lock);
617 parport_proc_unregister(port);
619 for (i = 1; i < 3; i++) {
620 struct parport *slave = port->slaves[i-1];
622 parport_put_port(slave);
625 EXPORT_SYMBOL(parport_remove_port);
628 * parport_register_device - register a device on a parallel port
629 * @port: port to which the device is attached
630 * @name: a name to refer to the device
631 * @pf: preemption callback
632 * @kf: kick callback (wake-up)
633 * @irq_func: interrupt handler
634 * @flags: registration flags
635 * @handle: data for callback functions
637 * This function, called by parallel port device drivers,
638 * declares that a device is connected to a port, and tells the
639 * system all it needs to know.
641 * The @name is allocated by the caller and must not be
642 * deallocated until the caller calls @parport_unregister_device
645 * The preemption callback function, @pf, is called when this
646 * device driver has claimed access to the port but another
647 * device driver wants to use it. It is given @handle as its
648 * parameter, and should return zero if it is willing for the
649 * system to release the port to another driver on its behalf.
650 * If it wants to keep control of the port it should return
651 * non-zero, and no action will be taken. It is good manners for
652 * the driver to try to release the port at the earliest
653 * opportunity after its preemption callback rejects a preemption
654 * attempt. Note that if a preemption callback is happy for
655 * preemption to go ahead, there is no need to release the port;
656 * it is done automatically. This function may not block, as it
657 * may be called from interrupt context. If the device driver
658 * does not support preemption, @pf can be %NULL.
660 * The wake-up ("kick") callback function, @kf, is called when
661 * the port is available to be claimed for exclusive access; that
662 * is, parport_claim() is guaranteed to succeed when called from
663 * inside the wake-up callback function. If the driver wants to
664 * claim the port it should do so; otherwise, it need not take
665 * any action. This function may not block, as it may be called
666 * from interrupt context. If the device driver does not want to
667 * be explicitly invited to claim the port in this way, @kf can
670 * The interrupt handler, @irq_func, is called when an interrupt
671 * arrives from the parallel port. Note that if a device driver
672 * wants to use interrupts it should use parport_enable_irq(),
673 * and can also check the irq member of the parport structure
674 * representing the port.
676 * The parallel port (lowlevel) driver is the one that has called
677 * request_irq() and whose interrupt handler is called first.
678 * This handler does whatever needs to be done to the hardware to
679 * acknowledge the interrupt (for PC-style ports there is nothing
680 * special to be done). It then tells the IEEE 1284 code about
681 * the interrupt, which may involve reacting to an IEEE 1284
682 * event depending on the current IEEE 1284 phase. After this,
683 * it calls @irq_func. Needless to say, @irq_func will be called
684 * from interrupt context, and may not block.
686 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
687 * so should only be used when sharing the port with other device
688 * drivers is impossible and would lead to incorrect behaviour.
689 * Use it sparingly! Normally, @flags will be zero.
691 * This function returns a pointer to a structure that represents
692 * the device on the port, or %NULL if there is not enough memory
693 * to allocate space for that structure.
697 parport_register_device(struct parport *port, const char *name,
698 int (*pf)(void *), void (*kf)(void *),
699 void (*irq_func)(void *),
700 int flags, void *handle)
702 struct pardevice *tmp;
704 if (port->physport->flags & PARPORT_FLAG_EXCL) {
705 /* An exclusive device is registered. */
706 printk (KERN_DEBUG "%s: no more devices allowed\n",
711 if (flags & PARPORT_DEV_LURK) {
713 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
718 if (flags & PARPORT_DEV_EXCL) {
719 if (port->physport->devices) {
721 * If a device is already registered and this new
722 * device wants exclusive access, then no need to
723 * continue as we can not grant exclusive access to
726 pr_err("%s: cannot grant exclusive access for device %s\n",
733 * We up our own module reference count, and that of the port
734 * on which a device is to be registered, to ensure that
735 * neither of us gets unloaded while we sleep in (e.g.)
738 if (!try_module_get(port->ops->owner))
741 parport_get_port (port);
743 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
745 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
749 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
750 if (tmp->state == NULL) {
751 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
752 goto out_free_pardevice;
760 tmp->private = handle;
762 tmp->irq_func = irq_func;
764 tmp->timeout = 5 * HZ;
765 tmp->devmodel = false;
767 /* Chain this onto the list */
770 * This function must not run from an irq handler so we don' t need
771 * to clear irq on the local CPU. -arca
773 spin_lock(&port->physport->pardevice_lock);
775 if (flags & PARPORT_DEV_EXCL) {
776 if (port->physport->devices) {
777 spin_unlock (&port->physport->pardevice_lock);
779 "%s: cannot grant exclusive access for device %s\n",
783 port->flags |= PARPORT_FLAG_EXCL;
786 tmp->next = port->physport->devices;
788 * Make sure that tmp->next is written before it's
789 * added to the list; see comments marked 'no locking
792 if (port->physport->devices)
793 port->physport->devices->prev = tmp;
794 port->physport->devices = tmp;
795 spin_unlock(&port->physport->pardevice_lock);
797 init_waitqueue_head(&tmp->wait_q);
798 tmp->timeslice = parport_default_timeslice;
799 tmp->waitnext = tmp->waitprev = NULL;
802 * This has to be run as last thing since init_state may need other
803 * pardevice fields. -arca
805 port->ops->init_state(tmp, tmp->state);
806 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
807 port->proc_device = tmp;
808 parport_device_proc_register(tmp);
817 parport_put_port (port);
818 module_put(port->ops->owner);
822 EXPORT_SYMBOL(parport_register_device);
824 static void free_pardevice(struct device *dev)
826 struct pardevice *par_dev = to_pardevice(dev);
828 kfree(par_dev->name);
833 parport_register_dev_model(struct parport *port, const char *name,
834 const struct pardev_cb *par_dev_cb, int id)
836 struct pardevice *par_dev;
840 if (port->physport->flags & PARPORT_FLAG_EXCL) {
841 /* An exclusive device is registered. */
842 pr_err("%s: no more devices allowed\n", port->name);
846 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
847 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
848 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
854 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
855 if (port->physport->devices) {
857 * If a device is already registered and this new
858 * device wants exclusive access, then no need to
859 * continue as we can not grant exclusive access to
862 pr_err("%s: cannot grant exclusive access for device %s\n",
868 if (!try_module_get(port->ops->owner))
871 parport_get_port(port);
873 par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
877 par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
879 goto err_put_par_dev;
881 devname = kstrdup(name, GFP_KERNEL);
883 goto err_free_par_dev;
885 par_dev->name = devname;
886 par_dev->port = port;
888 par_dev->preempt = par_dev_cb->preempt;
889 par_dev->wakeup = par_dev_cb->wakeup;
890 par_dev->private = par_dev_cb->private;
891 par_dev->flags = par_dev_cb->flags;
892 par_dev->irq_func = par_dev_cb->irq_func;
893 par_dev->waiting = 0;
894 par_dev->timeout = 5 * HZ;
896 par_dev->dev.parent = &port->bus_dev;
897 par_dev->dev.bus = &parport_bus_type;
898 ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
900 goto err_free_devname;
901 par_dev->dev.release = free_pardevice;
902 par_dev->devmodel = true;
903 ret = device_register(&par_dev->dev);
905 put_device(&par_dev->dev);
909 /* Chain this onto the list */
910 par_dev->prev = NULL;
912 * This function must not run from an irq handler so we don' t need
913 * to clear irq on the local CPU. -arca
915 spin_lock(&port->physport->pardevice_lock);
917 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
918 if (port->physport->devices) {
919 spin_unlock(&port->physport->pardevice_lock);
920 pr_debug("%s: cannot grant exclusive access for device %s\n",
922 device_unregister(&par_dev->dev);
925 port->flags |= PARPORT_FLAG_EXCL;
928 par_dev->next = port->physport->devices;
930 * Make sure that tmp->next is written before it's
931 * added to the list; see comments marked 'no locking
934 if (port->physport->devices)
935 port->physport->devices->prev = par_dev;
936 port->physport->devices = par_dev;
937 spin_unlock(&port->physport->pardevice_lock);
939 init_waitqueue_head(&par_dev->wait_q);
940 par_dev->timeslice = parport_default_timeslice;
941 par_dev->waitnext = NULL;
942 par_dev->waitprev = NULL;
945 * This has to be run as last thing since init_state may need other
946 * pardevice fields. -arca
948 port->ops->init_state(par_dev, par_dev->state);
949 port->proc_device = par_dev;
950 parport_device_proc_register(par_dev);
957 kfree(par_dev->state);
959 if (!par_dev->devmodel)
962 parport_put_port(port);
963 module_put(port->ops->owner);
967 EXPORT_SYMBOL(parport_register_dev_model);
970 * parport_unregister_device - deregister a device on a parallel port
971 * @dev: pointer to structure representing device
973 * This undoes the effect of parport_register_device().
976 void parport_unregister_device(struct pardevice *dev)
978 struct parport *port;
980 #ifdef PARPORT_PARANOID
982 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
987 port = dev->port->physport;
989 if (port->proc_device == dev) {
990 port->proc_device = NULL;
991 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
992 parport_device_proc_unregister(dev);
995 if (port->cad == dev) {
996 printk(KERN_DEBUG "%s: %s forgot to release port\n",
997 port->name, dev->name);
998 parport_release (dev);
1001 spin_lock(&port->pardevice_lock);
1003 dev->next->prev = dev->prev;
1005 dev->prev->next = dev->next;
1007 port->devices = dev->next;
1009 if (dev->flags & PARPORT_DEV_EXCL)
1010 port->flags &= ~PARPORT_FLAG_EXCL;
1012 spin_unlock(&port->pardevice_lock);
1015 * Make sure we haven't left any pointers around in the wait
1018 spin_lock_irq(&port->waitlist_lock);
1019 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1021 dev->waitprev->waitnext = dev->waitnext;
1023 port->waithead = dev->waitnext;
1025 dev->waitnext->waitprev = dev->waitprev;
1027 port->waittail = dev->waitprev;
1029 spin_unlock_irq(&port->waitlist_lock);
1033 device_unregister(&dev->dev);
1037 module_put(port->ops->owner);
1038 parport_put_port (port);
1040 EXPORT_SYMBOL(parport_unregister_device);
1043 * parport_find_number - find a parallel port by number
1044 * @number: parallel port number
1046 * This returns the parallel port with the specified number, or
1047 * %NULL if there is none.
1049 * There is an implicit parport_get_port() done already; to throw
1050 * away the reference to the port that parport_find_number()
1051 * gives you, use parport_put_port().
1054 struct parport *parport_find_number (int number)
1056 struct parport *port, *result = NULL;
1058 if (list_empty(&portlist))
1059 get_lowlevel_driver ();
1061 spin_lock (&parportlist_lock);
1062 list_for_each_entry(port, &portlist, list) {
1063 if (port->number == number) {
1064 result = parport_get_port (port);
1068 spin_unlock (&parportlist_lock);
1071 EXPORT_SYMBOL(parport_find_number);
1074 * parport_find_base - find a parallel port by base address
1075 * @base: base I/O address
1077 * This returns the parallel port with the specified base
1078 * address, or %NULL if there is none.
1080 * There is an implicit parport_get_port() done already; to throw
1081 * away the reference to the port that parport_find_base()
1082 * gives you, use parport_put_port().
1085 struct parport *parport_find_base (unsigned long base)
1087 struct parport *port, *result = NULL;
1089 if (list_empty(&portlist))
1090 get_lowlevel_driver ();
1092 spin_lock (&parportlist_lock);
1093 list_for_each_entry(port, &portlist, list) {
1094 if (port->base == base) {
1095 result = parport_get_port (port);
1099 spin_unlock (&parportlist_lock);
1102 EXPORT_SYMBOL(parport_find_base);
1105 * parport_claim - claim access to a parallel port device
1106 * @dev: pointer to structure representing a device on the port
1108 * This function will not block and so can be used from interrupt
1109 * context. If parport_claim() succeeds in claiming access to
1110 * the port it returns zero and the port is available to use. It
1111 * may fail (returning non-zero) if the port is in use by another
1112 * driver and that driver is not willing to relinquish control of
1116 int parport_claim(struct pardevice *dev)
1118 struct pardevice *oldcad;
1119 struct parport *port = dev->port->physport;
1120 unsigned long flags;
1122 if (port->cad == dev) {
1123 printk(KERN_INFO "%s: %s already owner\n",
1124 dev->port->name,dev->name);
1128 /* Preempt any current device */
1129 write_lock_irqsave (&port->cad_lock, flags);
1130 if ((oldcad = port->cad) != NULL) {
1131 if (oldcad->preempt) {
1132 if (oldcad->preempt(oldcad->private))
1134 port->ops->save_state(port, dev->state);
1138 if (port->cad != oldcad) {
1140 * I think we'll actually deadlock rather than
1141 * get here, but just in case..
1144 "%s: %s released port when preempted!\n",
1145 port->name, oldcad->name);
1151 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1152 if (dev->waiting & 1) {
1155 /* Take ourselves out of the wait list again. */
1156 spin_lock_irq (&port->waitlist_lock);
1158 dev->waitprev->waitnext = dev->waitnext;
1160 port->waithead = dev->waitnext;
1162 dev->waitnext->waitprev = dev->waitprev;
1164 port->waittail = dev->waitprev;
1165 spin_unlock_irq (&port->waitlist_lock);
1166 dev->waitprev = dev->waitnext = NULL;
1169 /* Now we do the change of devices */
1172 #ifdef CONFIG_PARPORT_1284
1173 /* If it's a mux port, select it. */
1174 if (dev->port->muxport >= 0) {
1176 port->muxsel = dev->port->muxport;
1179 /* If it's a daisy chain device, select it. */
1180 if (dev->daisy >= 0) {
1181 /* This could be lazier. */
1182 if (!parport_daisy_select (port, dev->daisy,
1183 IEEE1284_MODE_COMPAT))
1184 port->daisy = dev->daisy;
1186 #endif /* IEEE1284.3 support */
1188 /* Restore control registers */
1189 port->ops->restore_state(port, dev->state);
1190 write_unlock_irqrestore(&port->cad_lock, flags);
1191 dev->time = jiffies;
1196 * If this is the first time we tried to claim the port, register an
1197 * interest. This is only allowed for devices sleeping in
1198 * parport_claim_or_block(), or those with a wakeup function.
1201 /* The cad_lock is still held for writing here */
1202 if (dev->waiting & 2 || dev->wakeup) {
1203 spin_lock (&port->waitlist_lock);
1204 if (test_and_set_bit(0, &dev->waiting) == 0) {
1205 /* First add ourselves to the end of the wait list. */
1206 dev->waitnext = NULL;
1207 dev->waitprev = port->waittail;
1208 if (port->waittail) {
1209 port->waittail->waitnext = dev;
1210 port->waittail = dev;
1212 port->waithead = port->waittail = dev;
1214 spin_unlock (&port->waitlist_lock);
1216 write_unlock_irqrestore (&port->cad_lock, flags);
1219 EXPORT_SYMBOL(parport_claim);
1222 * parport_claim_or_block - claim access to a parallel port device
1223 * @dev: pointer to structure representing a device on the port
1225 * This behaves like parport_claim(), but will block if necessary
1226 * to wait for the port to be free. A return value of 1
1227 * indicates that it slept; 0 means that it succeeded without
1228 * needing to sleep. A negative error code indicates failure.
1231 int parport_claim_or_block(struct pardevice *dev)
1236 * Signal to parport_claim() that we can wait even without a
1241 /* Try to claim the port. If this fails, we need to sleep. */
1242 r = parport_claim(dev);
1244 #ifdef PARPORT_DEBUG_SHARING
1245 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1248 * FIXME!!! Use the proper locking for dev->waiting,
1249 * and make this use the "wait_event_interruptible()"
1250 * interfaces. The cli/sti that used to be here
1253 * See also parport_release()
1257 * If dev->waiting is clear now, an interrupt
1258 * gave us the port and we would deadlock if we slept.
1261 wait_event_interruptible(dev->wait_q,
1263 if (signal_pending (current))
1268 #ifdef PARPORT_DEBUG_SHARING
1269 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1274 #ifdef PARPORT_DEBUG_SHARING
1275 if (dev->port->physport->cad != dev)
1276 printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1277 dev->name, dev->port->physport->cad ?
1278 dev->port->physport->cad->name:"nobody");
1284 EXPORT_SYMBOL(parport_claim_or_block);
1287 * parport_release - give up access to a parallel port device
1288 * @dev: pointer to structure representing parallel port device
1290 * This function cannot fail, but it should not be called without
1291 * the port claimed. Similarly, if the port is already claimed
1292 * you should not try claiming it again.
1295 void parport_release(struct pardevice *dev)
1297 struct parport *port = dev->port->physport;
1298 struct pardevice *pd;
1299 unsigned long flags;
1301 /* Make sure that dev is the current device */
1302 write_lock_irqsave(&port->cad_lock, flags);
1303 if (port->cad != dev) {
1304 write_unlock_irqrestore (&port->cad_lock, flags);
1305 printk(KERN_WARNING "%s: %s tried to release parport when not owner\n",
1306 port->name, dev->name);
1310 #ifdef CONFIG_PARPORT_1284
1311 /* If this is on a mux port, deselect it. */
1312 if (dev->port->muxport >= 0) {
1317 /* If this is a daisy device, deselect it. */
1318 if (dev->daisy >= 0) {
1319 parport_daisy_deselect_all (port);
1325 write_unlock_irqrestore(&port->cad_lock, flags);
1327 /* Save control registers */
1328 port->ops->save_state(port, dev->state);
1331 * If anybody is waiting, find out who's been there longest and
1332 * then wake them up. (Note: no locking required)
1334 /* !!! LOCKING IS NEEDED HERE */
1335 for (pd = port->waithead; pd; pd = pd->waitnext) {
1336 if (pd->waiting & 2) { /* sleeping in claim_or_block */
1338 if (waitqueue_active(&pd->wait_q))
1339 wake_up_interruptible(&pd->wait_q);
1341 } else if (pd->wakeup) {
1342 pd->wakeup(pd->private);
1343 if (dev->port->cad) /* racy but no matter */
1346 printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
1351 * Nobody was waiting, so walk the list to see if anyone is
1352 * interested in being woken up. (Note: no locking required)
1354 /* !!! LOCKING IS NEEDED HERE */
1355 for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) {
1356 if (pd->wakeup && pd != dev)
1357 pd->wakeup(pd->private);
1360 EXPORT_SYMBOL(parport_release);
1362 irqreturn_t parport_irq_handler(int irq, void *dev_id)
1364 struct parport *port = dev_id;
1366 parport_generic_irq(port);
1370 EXPORT_SYMBOL(parport_irq_handler);
1372 MODULE_LICENSE("GPL");