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/signal.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)
142 retval = bus_register(&parport_bus_type);
150 void parport_bus_exit(void)
153 bus_unregister(&parport_bus_type);
157 * iterates through all the drivers registered with the bus and sends the port
158 * details to the match_port callback of the driver, so that the driver can
159 * know about the new port that just registered with the bus and decide if it
160 * wants to use this new port.
162 static int driver_check(struct device_driver *dev_drv, void *_port)
164 struct parport *port = _port;
165 struct parport_driver *drv = to_parport_driver(dev_drv);
168 drv->match_port(port);
172 /* Call attach(port) for each registered driver. */
173 static void attach_driver_chain(struct parport *port)
175 /* caller has exclusive registration_lock */
176 struct parport_driver *drv;
178 list_for_each_entry(drv, &drivers, list)
182 * call the driver_check function of the drivers registered in
186 bus_for_each_drv(&parport_bus_type, NULL, port, driver_check);
189 static int driver_detach(struct device_driver *_drv, void *_port)
191 struct parport *port = _port;
192 struct parport_driver *drv = to_parport_driver(_drv);
199 /* Call detach(port) for each registered driver. */
200 static void detach_driver_chain(struct parport *port)
202 struct parport_driver *drv;
203 /* caller has exclusive registration_lock */
204 list_for_each_entry(drv, &drivers, list)
208 * call the detach function of the drivers registered in
212 bus_for_each_drv(&parport_bus_type, NULL, port, driver_detach);
215 /* Ask kmod for some lowlevel drivers. */
216 static void get_lowlevel_driver(void)
219 * There is no actual module called this: you should set
220 * up an alias for modutils.
222 request_module("parport_lowlevel");
226 * iterates through all the devices connected to the bus and sends the device
227 * details to the match_port callback of the driver, so that the driver can
228 * know what are all the ports that are connected to the bus and choose the
229 * port to which it wants to register its device.
231 static int port_check(struct device *dev, void *dev_drv)
233 struct parport_driver *drv = dev_drv;
235 /* only send ports, do not send other devices connected to bus */
237 drv->match_port(to_parport_dev(dev));
242 * parport_register_driver - register a parallel port device driver
243 * @drv: structure describing the driver
244 * @owner: owner module of drv
245 * @mod_name: module name string
247 * This can be called by a parallel port device driver in order
248 * to receive notifications about ports being found in the
249 * system, as well as ports no longer available.
251 * If devmodel is true then the new device model is used
254 * The @drv structure is allocated by the caller and must not be
255 * deallocated until after calling parport_unregister_driver().
257 * If using the non device model:
258 * The driver's attach() function may block. The port that
259 * attach() is given will be valid for the duration of the
260 * callback, but if the driver wants to take a copy of the
261 * pointer it must call parport_get_port() to do so. Calling
262 * parport_register_device() on that port will do this for you.
264 * The driver's detach() function may block. The port that
265 * detach() is given will be valid for the duration of the
266 * callback, but if the driver wants to take a copy of the
267 * pointer it must call parport_get_port() to do so.
270 * Returns 0 on success. The non device model will always succeeds.
271 * but the new device model can fail and will return the error code.
274 int __parport_register_driver(struct parport_driver *drv, struct module *owner,
275 const char *mod_name)
277 if (list_empty(&portlist))
278 get_lowlevel_driver();
281 /* using device model */
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);
293 mutex_lock(®istration_lock);
295 bus_for_each_dev(&parport_bus_type, NULL, drv,
297 mutex_unlock(®istration_lock);
299 struct parport *port;
301 drv->devmodel = false;
303 mutex_lock(®istration_lock);
304 list_for_each_entry(port, &portlist, list)
306 list_add(&drv->list, &drivers);
307 mutex_unlock(®istration_lock);
312 EXPORT_SYMBOL(__parport_register_driver);
314 static int port_detach(struct device *dev, void *_drv)
316 struct parport_driver *drv = _drv;
318 if (is_parport(dev) && drv->detach)
319 drv->detach(to_parport_dev(dev));
325 * parport_unregister_driver - deregister a parallel port device driver
326 * @drv: structure describing the driver that was given to
327 * parport_register_driver()
329 * This should be called by a parallel port device driver that
330 * has registered itself using parport_register_driver() when it
331 * is about to be unloaded.
333 * When it returns, the driver's attach() routine will no longer
334 * be called, and for each port that attach() was called for, the
335 * detach() routine will have been called.
337 * All the driver's attach() and detach() calls are guaranteed to have
338 * finished by the time this function returns.
341 void parport_unregister_driver(struct parport_driver *drv)
343 struct parport *port;
345 mutex_lock(®istration_lock);
347 bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
348 driver_unregister(&drv->driver);
350 list_del_init(&drv->list);
351 list_for_each_entry(port, &portlist, list)
354 mutex_unlock(®istration_lock);
356 EXPORT_SYMBOL(parport_unregister_driver);
358 static void free_port(struct device *dev)
361 struct parport *port = to_parport_dev(dev);
363 spin_lock(&full_list_lock);
364 list_del(&port->full_list);
365 spin_unlock(&full_list_lock);
366 for (d = 0; d < 5; d++) {
367 kfree(port->probe_info[d].class_name);
368 kfree(port->probe_info[d].mfr);
369 kfree(port->probe_info[d].model);
370 kfree(port->probe_info[d].cmdset);
371 kfree(port->probe_info[d].description);
379 * parport_get_port - increment a port's reference count
382 * This ensures that a struct parport pointer remains valid
383 * until the matching parport_put_port() call.
386 struct parport *parport_get_port(struct parport *port)
388 struct device *dev = get_device(&port->bus_dev);
390 return to_parport_dev(dev);
392 EXPORT_SYMBOL(parport_get_port);
394 void parport_del_port(struct parport *port)
396 device_unregister(&port->bus_dev);
398 EXPORT_SYMBOL(parport_del_port);
401 * parport_put_port - decrement a port's reference count
404 * This should be called once for each call to parport_get_port(),
405 * once the port is no longer needed. When the reference count reaches
406 * zero (port is no longer used), free_port is called.
409 void parport_put_port(struct parport *port)
411 put_device(&port->bus_dev);
413 EXPORT_SYMBOL(parport_put_port);
416 * parport_register_port - register a parallel port
417 * @base: base I/O address
420 * @ops: pointer to the port driver's port operations structure
422 * When a parallel port (lowlevel) driver finds a port that
423 * should be made available to parallel port device drivers, it
424 * should call parport_register_port(). The @base, @irq, and
425 * @dma parameters are for the convenience of port drivers, and
426 * for ports where they aren't meaningful needn't be set to
427 * anything special. They can be altered afterwards by adjusting
428 * the relevant members of the parport structure that is returned
429 * and represents the port. They should not be tampered with
430 * after calling parport_announce_port, however.
432 * If there are parallel port device drivers in the system that
433 * have registered themselves using parport_register_driver(),
434 * they are not told about the port at this time; that is done by
435 * parport_announce_port().
437 * The @ops structure is allocated by the caller, and must not be
438 * deallocated before calling parport_remove_port().
440 * If there is no memory to allocate a new parport structure,
441 * this function will return %NULL.
444 struct parport *parport_register_port(unsigned long base, int irq, int dma,
445 struct parport_operations *ops)
454 tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
458 /* Init our structure */
462 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
464 INIT_LIST_HEAD(&tmp->list);
465 tmp->devices = tmp->cad = NULL;
469 memset(tmp->probe_info, 0, 5 * sizeof(struct parport_device_info));
470 rwlock_init(&tmp->cad_lock);
471 spin_lock_init(&tmp->waitlist_lock);
472 spin_lock_init(&tmp->pardevice_lock);
473 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
474 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
475 sema_init(&tmp->ieee1284.irq, 0);
476 tmp->spintime = parport_default_spintime;
477 atomic_set(&tmp->ref_count, 1);
478 INIT_LIST_HEAD(&tmp->full_list);
480 name = kmalloc(15, GFP_KERNEL);
485 /* Search for the lowest free parport number. */
487 spin_lock(&full_list_lock);
488 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
489 struct parport *p = list_entry(l, struct parport, full_list);
490 if (p->number != num)
493 tmp->portnum = tmp->number = num;
494 list_add_tail(&tmp->full_list, l);
495 spin_unlock(&full_list_lock);
498 * Now that the portnum is known finish doing the Init.
500 sprintf(name, "parport%d", tmp->portnum = tmp->number);
502 tmp->bus_dev.bus = &parport_bus_type;
503 tmp->bus_dev.release = free_port;
504 dev_set_name(&tmp->bus_dev, name);
505 tmp->bus_dev.type = &parport_device_type;
507 for (device = 0; device < 5; device++)
508 /* assume the worst */
509 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
511 tmp->waithead = tmp->waittail = NULL;
513 ret = device_register(&tmp->bus_dev);
515 put_device(&tmp->bus_dev);
521 EXPORT_SYMBOL(parport_register_port);
524 * parport_announce_port - tell device drivers about a parallel port
525 * @port: parallel port to announce
527 * After a port driver has registered a parallel port with
528 * parport_register_port, and performed any necessary
529 * initialisation or adjustments, it should call
530 * parport_announce_port() in order to notify all device drivers
531 * that have called parport_register_driver(). Their attach()
532 * functions will be called, with @port as the parameter.
535 void parport_announce_port(struct parport *port)
539 #ifdef CONFIG_PARPORT_1284
540 /* Analyse the IEEE1284.3 topology of the port. */
541 parport_daisy_init(port);
545 printk(KERN_WARNING "%s: fix this legacy no-device port driver!\n",
548 parport_proc_register(port);
549 mutex_lock(®istration_lock);
550 spin_lock_irq(&parportlist_lock);
551 list_add_tail(&port->list, &portlist);
552 for (i = 1; i < 3; i++) {
553 struct parport *slave = port->slaves[i-1];
555 list_add_tail(&slave->list, &portlist);
557 spin_unlock_irq(&parportlist_lock);
559 /* Let drivers know that new port(s) has arrived. */
560 attach_driver_chain(port);
561 for (i = 1; i < 3; i++) {
562 struct parport *slave = port->slaves[i-1];
564 attach_driver_chain(slave);
566 mutex_unlock(®istration_lock);
568 EXPORT_SYMBOL(parport_announce_port);
571 * parport_remove_port - deregister a parallel port
572 * @port: parallel port to deregister
574 * When a parallel port driver is forcibly unloaded, or a
575 * parallel port becomes inaccessible, the port driver must call
576 * this function in order to deal with device drivers that still
579 * The parport structure associated with the port has its
580 * operations structure replaced with one containing 'null'
581 * operations that return errors or just don't do anything.
583 * Any drivers that have registered themselves using
584 * parport_register_driver() are notified that the port is no
585 * longer accessible by having their detach() routines called
586 * with @port as the parameter.
589 void parport_remove_port(struct parport *port)
593 mutex_lock(®istration_lock);
595 /* Spread the word. */
596 detach_driver_chain(port);
598 #ifdef CONFIG_PARPORT_1284
599 /* Forget the IEEE1284.3 topology of the port. */
600 parport_daisy_fini(port);
601 for (i = 1; i < 3; i++) {
602 struct parport *slave = port->slaves[i-1];
605 detach_driver_chain(slave);
606 parport_daisy_fini(slave);
610 port->ops = &dead_ops;
611 spin_lock(&parportlist_lock);
612 list_del_init(&port->list);
613 for (i = 1; i < 3; i++) {
614 struct parport *slave = port->slaves[i-1];
616 list_del_init(&slave->list);
618 spin_unlock(&parportlist_lock);
620 mutex_unlock(®istration_lock);
622 parport_proc_unregister(port);
624 for (i = 1; i < 3; i++) {
625 struct parport *slave = port->slaves[i-1];
627 parport_put_port(slave);
630 EXPORT_SYMBOL(parport_remove_port);
633 * parport_register_device - register a device on a parallel port
634 * @port: port to which the device is attached
635 * @name: a name to refer to the device
636 * @pf: preemption callback
637 * @kf: kick callback (wake-up)
638 * @irq_func: interrupt handler
639 * @flags: registration flags
640 * @handle: data for callback functions
642 * This function, called by parallel port device drivers,
643 * declares that a device is connected to a port, and tells the
644 * system all it needs to know.
646 * The @name is allocated by the caller and must not be
647 * deallocated until the caller calls @parport_unregister_device
650 * The preemption callback function, @pf, is called when this
651 * device driver has claimed access to the port but another
652 * device driver wants to use it. It is given @handle as its
653 * parameter, and should return zero if it is willing for the
654 * system to release the port to another driver on its behalf.
655 * If it wants to keep control of the port it should return
656 * non-zero, and no action will be taken. It is good manners for
657 * the driver to try to release the port at the earliest
658 * opportunity after its preemption callback rejects a preemption
659 * attempt. Note that if a preemption callback is happy for
660 * preemption to go ahead, there is no need to release the port;
661 * it is done automatically. This function may not block, as it
662 * may be called from interrupt context. If the device driver
663 * does not support preemption, @pf can be %NULL.
665 * The wake-up ("kick") callback function, @kf, is called when
666 * the port is available to be claimed for exclusive access; that
667 * is, parport_claim() is guaranteed to succeed when called from
668 * inside the wake-up callback function. If the driver wants to
669 * claim the port it should do so; otherwise, it need not take
670 * any action. This function may not block, as it may be called
671 * from interrupt context. If the device driver does not want to
672 * be explicitly invited to claim the port in this way, @kf can
675 * The interrupt handler, @irq_func, is called when an interrupt
676 * arrives from the parallel port. Note that if a device driver
677 * wants to use interrupts it should use parport_enable_irq(),
678 * and can also check the irq member of the parport structure
679 * representing the port.
681 * The parallel port (lowlevel) driver is the one that has called
682 * request_irq() and whose interrupt handler is called first.
683 * This handler does whatever needs to be done to the hardware to
684 * acknowledge the interrupt (for PC-style ports there is nothing
685 * special to be done). It then tells the IEEE 1284 code about
686 * the interrupt, which may involve reacting to an IEEE 1284
687 * event depending on the current IEEE 1284 phase. After this,
688 * it calls @irq_func. Needless to say, @irq_func will be called
689 * from interrupt context, and may not block.
691 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
692 * so should only be used when sharing the port with other device
693 * drivers is impossible and would lead to incorrect behaviour.
694 * Use it sparingly! Normally, @flags will be zero.
696 * This function returns a pointer to a structure that represents
697 * the device on the port, or %NULL if there is not enough memory
698 * to allocate space for that structure.
702 parport_register_device(struct parport *port, const char *name,
703 int (*pf)(void *), void (*kf)(void *),
704 void (*irq_func)(void *),
705 int flags, void *handle)
707 struct pardevice *tmp;
709 if (port->physport->flags & PARPORT_FLAG_EXCL) {
710 /* An exclusive device is registered. */
711 printk(KERN_DEBUG "%s: no more devices allowed\n",
716 if (flags & PARPORT_DEV_LURK) {
718 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
723 if (flags & PARPORT_DEV_EXCL) {
724 if (port->physport->devices) {
726 * If a device is already registered and this new
727 * device wants exclusive access, then no need to
728 * continue as we can not grant exclusive access to
731 pr_err("%s: cannot grant exclusive access for device %s\n",
738 * We up our own module reference count, and that of the port
739 * on which a device is to be registered, to ensure that
740 * neither of us gets unloaded while we sleep in (e.g.)
743 if (!try_module_get(port->ops->owner))
746 parport_get_port(port);
748 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
752 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
754 goto out_free_pardevice;
761 tmp->private = handle;
763 tmp->irq_func = irq_func;
765 tmp->timeout = 5 * HZ;
766 tmp->devmodel = false;
768 /* Chain this onto the list */
771 * This function must not run from an irq handler so we don' t need
772 * to clear irq on the local CPU. -arca
774 spin_lock(&port->physport->pardevice_lock);
776 if (flags & PARPORT_DEV_EXCL) {
777 if (port->physport->devices) {
778 spin_unlock(&port->physport->pardevice_lock);
780 "%s: cannot grant exclusive access for device %s\n",
784 port->flags |= PARPORT_FLAG_EXCL;
787 tmp->next = port->physport->devices;
789 * Make sure that tmp->next is written before it's
790 * added to the list; see comments marked 'no locking
793 if (port->physport->devices)
794 port->physport->devices->prev = tmp;
795 port->physport->devices = tmp;
796 spin_unlock(&port->physport->pardevice_lock);
798 init_waitqueue_head(&tmp->wait_q);
799 tmp->timeslice = parport_default_timeslice;
800 tmp->waitnext = tmp->waitprev = NULL;
803 * This has to be run as last thing since init_state may need other
804 * pardevice fields. -arca
806 port->ops->init_state(tmp, tmp->state);
807 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
808 port->proc_device = tmp;
809 parport_device_proc_register(tmp);
818 parport_put_port(port);
819 module_put(port->ops->owner);
823 EXPORT_SYMBOL(parport_register_device);
825 static void free_pardevice(struct device *dev)
827 struct pardevice *par_dev = to_pardevice(dev);
829 kfree(par_dev->name);
834 parport_register_dev_model(struct parport *port, const char *name,
835 const struct pardev_cb *par_dev_cb, int id)
837 struct pardevice *par_dev;
841 if (port->physport->flags & PARPORT_FLAG_EXCL) {
842 /* An exclusive device is registered. */
843 pr_err("%s: no more devices allowed\n", port->name);
847 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
848 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
849 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
855 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
856 if (port->physport->devices) {
858 * If a device is already registered and this new
859 * device wants exclusive access, then no need to
860 * continue as we can not grant exclusive access to
863 pr_err("%s: cannot grant exclusive access for device %s\n",
869 if (!try_module_get(port->ops->owner))
872 parport_get_port(port);
874 par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
878 par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
880 goto err_put_par_dev;
882 devname = kstrdup(name, GFP_KERNEL);
884 goto err_free_par_dev;
886 par_dev->name = devname;
887 par_dev->port = port;
889 par_dev->preempt = par_dev_cb->preempt;
890 par_dev->wakeup = par_dev_cb->wakeup;
891 par_dev->private = par_dev_cb->private;
892 par_dev->flags = par_dev_cb->flags;
893 par_dev->irq_func = par_dev_cb->irq_func;
894 par_dev->waiting = 0;
895 par_dev->timeout = 5 * HZ;
897 par_dev->dev.parent = &port->bus_dev;
898 par_dev->dev.bus = &parport_bus_type;
899 ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
901 goto err_free_devname;
902 par_dev->dev.release = free_pardevice;
903 par_dev->devmodel = true;
904 ret = device_register(&par_dev->dev);
906 put_device(&par_dev->dev);
910 /* Chain this onto the list */
911 par_dev->prev = NULL;
913 * This function must not run from an irq handler so we don' t need
914 * to clear irq on the local CPU. -arca
916 spin_lock(&port->physport->pardevice_lock);
918 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
919 if (port->physport->devices) {
920 spin_unlock(&port->physport->pardevice_lock);
921 pr_debug("%s: cannot grant exclusive access for device %s\n",
923 device_unregister(&par_dev->dev);
926 port->flags |= PARPORT_FLAG_EXCL;
929 par_dev->next = port->physport->devices;
931 * Make sure that tmp->next is written before it's
932 * added to the list; see comments marked 'no locking
935 if (port->physport->devices)
936 port->physport->devices->prev = par_dev;
937 port->physport->devices = par_dev;
938 spin_unlock(&port->physport->pardevice_lock);
940 init_waitqueue_head(&par_dev->wait_q);
941 par_dev->timeslice = parport_default_timeslice;
942 par_dev->waitnext = NULL;
943 par_dev->waitprev = NULL;
946 * This has to be run as last thing since init_state may need other
947 * pardevice fields. -arca
949 port->ops->init_state(par_dev, par_dev->state);
950 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
951 port->proc_device = par_dev;
952 parport_device_proc_register(par_dev);
960 kfree(par_dev->state);
962 if (!par_dev->devmodel)
965 parport_put_port(port);
966 module_put(port->ops->owner);
970 EXPORT_SYMBOL(parport_register_dev_model);
973 * parport_unregister_device - deregister a device on a parallel port
974 * @dev: pointer to structure representing device
976 * This undoes the effect of parport_register_device().
979 void parport_unregister_device(struct pardevice *dev)
981 struct parport *port;
983 #ifdef PARPORT_PARANOID
985 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
990 port = dev->port->physport;
992 if (port->proc_device == dev) {
993 port->proc_device = NULL;
994 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
995 parport_device_proc_unregister(dev);
998 if (port->cad == dev) {
999 printk(KERN_DEBUG "%s: %s forgot to release port\n",
1000 port->name, dev->name);
1001 parport_release(dev);
1004 spin_lock(&port->pardevice_lock);
1006 dev->next->prev = dev->prev;
1008 dev->prev->next = dev->next;
1010 port->devices = dev->next;
1012 if (dev->flags & PARPORT_DEV_EXCL)
1013 port->flags &= ~PARPORT_FLAG_EXCL;
1015 spin_unlock(&port->pardevice_lock);
1018 * Make sure we haven't left any pointers around in the wait
1021 spin_lock_irq(&port->waitlist_lock);
1022 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1024 dev->waitprev->waitnext = dev->waitnext;
1026 port->waithead = dev->waitnext;
1028 dev->waitnext->waitprev = dev->waitprev;
1030 port->waittail = dev->waitprev;
1032 spin_unlock_irq(&port->waitlist_lock);
1036 device_unregister(&dev->dev);
1040 module_put(port->ops->owner);
1041 parport_put_port(port);
1043 EXPORT_SYMBOL(parport_unregister_device);
1046 * parport_find_number - find a parallel port by number
1047 * @number: parallel port number
1049 * This returns the parallel port with the specified number, or
1050 * %NULL if there is none.
1052 * There is an implicit parport_get_port() done already; to throw
1053 * away the reference to the port that parport_find_number()
1054 * gives you, use parport_put_port().
1057 struct parport *parport_find_number(int number)
1059 struct parport *port, *result = NULL;
1061 if (list_empty(&portlist))
1062 get_lowlevel_driver();
1064 spin_lock(&parportlist_lock);
1065 list_for_each_entry(port, &portlist, list) {
1066 if (port->number == number) {
1067 result = parport_get_port(port);
1071 spin_unlock(&parportlist_lock);
1074 EXPORT_SYMBOL(parport_find_number);
1077 * parport_find_base - find a parallel port by base address
1078 * @base: base I/O address
1080 * This returns the parallel port with the specified base
1081 * address, or %NULL if there is none.
1083 * There is an implicit parport_get_port() done already; to throw
1084 * away the reference to the port that parport_find_base()
1085 * gives you, use parport_put_port().
1088 struct parport *parport_find_base(unsigned long base)
1090 struct parport *port, *result = NULL;
1092 if (list_empty(&portlist))
1093 get_lowlevel_driver();
1095 spin_lock(&parportlist_lock);
1096 list_for_each_entry(port, &portlist, list) {
1097 if (port->base == base) {
1098 result = parport_get_port(port);
1102 spin_unlock(&parportlist_lock);
1105 EXPORT_SYMBOL(parport_find_base);
1108 * parport_claim - claim access to a parallel port device
1109 * @dev: pointer to structure representing a device on the port
1111 * This function will not block and so can be used from interrupt
1112 * context. If parport_claim() succeeds in claiming access to
1113 * the port it returns zero and the port is available to use. It
1114 * may fail (returning non-zero) if the port is in use by another
1115 * driver and that driver is not willing to relinquish control of
1119 int parport_claim(struct pardevice *dev)
1121 struct pardevice *oldcad;
1122 struct parport *port = dev->port->physport;
1123 unsigned long flags;
1125 if (port->cad == dev) {
1126 printk(KERN_INFO "%s: %s already owner\n",
1127 dev->port->name,dev->name);
1131 /* Preempt any current device */
1132 write_lock_irqsave(&port->cad_lock, flags);
1135 if (oldcad->preempt) {
1136 if (oldcad->preempt(oldcad->private))
1138 port->ops->save_state(port, dev->state);
1142 if (port->cad != oldcad) {
1144 * I think we'll actually deadlock rather than
1145 * get here, but just in case..
1148 "%s: %s released port when preempted!\n",
1149 port->name, oldcad->name);
1155 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1156 if (dev->waiting & 1) {
1159 /* Take ourselves out of the wait list again. */
1160 spin_lock_irq(&port->waitlist_lock);
1162 dev->waitprev->waitnext = dev->waitnext;
1164 port->waithead = dev->waitnext;
1166 dev->waitnext->waitprev = dev->waitprev;
1168 port->waittail = dev->waitprev;
1169 spin_unlock_irq(&port->waitlist_lock);
1170 dev->waitprev = dev->waitnext = NULL;
1173 /* Now we do the change of devices */
1176 #ifdef CONFIG_PARPORT_1284
1177 /* If it's a mux port, select it. */
1178 if (dev->port->muxport >= 0) {
1180 port->muxsel = dev->port->muxport;
1183 /* If it's a daisy chain device, select it. */
1184 if (dev->daisy >= 0) {
1185 /* This could be lazier. */
1186 if (!parport_daisy_select(port, dev->daisy,
1187 IEEE1284_MODE_COMPAT))
1188 port->daisy = dev->daisy;
1190 #endif /* IEEE1284.3 support */
1192 /* Restore control registers */
1193 port->ops->restore_state(port, dev->state);
1194 write_unlock_irqrestore(&port->cad_lock, flags);
1195 dev->time = jiffies;
1200 * If this is the first time we tried to claim the port, register an
1201 * interest. This is only allowed for devices sleeping in
1202 * parport_claim_or_block(), or those with a wakeup function.
1205 /* The cad_lock is still held for writing here */
1206 if (dev->waiting & 2 || dev->wakeup) {
1207 spin_lock(&port->waitlist_lock);
1208 if (test_and_set_bit(0, &dev->waiting) == 0) {
1209 /* First add ourselves to the end of the wait list. */
1210 dev->waitnext = NULL;
1211 dev->waitprev = port->waittail;
1212 if (port->waittail) {
1213 port->waittail->waitnext = dev;
1214 port->waittail = dev;
1216 port->waithead = port->waittail = dev;
1218 spin_unlock(&port->waitlist_lock);
1220 write_unlock_irqrestore(&port->cad_lock, flags);
1223 EXPORT_SYMBOL(parport_claim);
1226 * parport_claim_or_block - claim access to a parallel port device
1227 * @dev: pointer to structure representing a device on the port
1229 * This behaves like parport_claim(), but will block if necessary
1230 * to wait for the port to be free. A return value of 1
1231 * indicates that it slept; 0 means that it succeeded without
1232 * needing to sleep. A negative error code indicates failure.
1235 int parport_claim_or_block(struct pardevice *dev)
1240 * Signal to parport_claim() that we can wait even without a
1245 /* Try to claim the port. If this fails, we need to sleep. */
1246 r = parport_claim(dev);
1248 #ifdef PARPORT_DEBUG_SHARING
1249 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1252 * FIXME!!! Use the proper locking for dev->waiting,
1253 * and make this use the "wait_event_interruptible()"
1254 * interfaces. The cli/sti that used to be here
1257 * See also parport_release()
1261 * If dev->waiting is clear now, an interrupt
1262 * gave us the port and we would deadlock if we slept.
1265 wait_event_interruptible(dev->wait_q,
1267 if (signal_pending(current))
1272 #ifdef PARPORT_DEBUG_SHARING
1273 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1278 #ifdef PARPORT_DEBUG_SHARING
1279 if (dev->port->physport->cad != dev)
1280 printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1281 dev->name, dev->port->physport->cad ?
1282 dev->port->physport->cad->name:"nobody");
1288 EXPORT_SYMBOL(parport_claim_or_block);
1291 * parport_release - give up access to a parallel port device
1292 * @dev: pointer to structure representing parallel port device
1294 * This function cannot fail, but it should not be called without
1295 * the port claimed. Similarly, if the port is already claimed
1296 * you should not try claiming it again.
1299 void parport_release(struct pardevice *dev)
1301 struct parport *port = dev->port->physport;
1302 struct pardevice *pd;
1303 unsigned long flags;
1305 /* Make sure that dev is the current device */
1306 write_lock_irqsave(&port->cad_lock, flags);
1307 if (port->cad != dev) {
1308 write_unlock_irqrestore(&port->cad_lock, flags);
1309 printk(KERN_WARNING "%s: %s tried to release parport when not owner\n",
1310 port->name, dev->name);
1314 #ifdef CONFIG_PARPORT_1284
1315 /* If this is on a mux port, deselect it. */
1316 if (dev->port->muxport >= 0) {
1321 /* If this is a daisy device, deselect it. */
1322 if (dev->daisy >= 0) {
1323 parport_daisy_deselect_all(port);
1329 write_unlock_irqrestore(&port->cad_lock, flags);
1331 /* Save control registers */
1332 port->ops->save_state(port, dev->state);
1335 * If anybody is waiting, find out who's been there longest and
1336 * then wake them up. (Note: no locking required)
1338 /* !!! LOCKING IS NEEDED HERE */
1339 for (pd = port->waithead; pd; pd = pd->waitnext) {
1340 if (pd->waiting & 2) { /* sleeping in claim_or_block */
1342 if (waitqueue_active(&pd->wait_q))
1343 wake_up_interruptible(&pd->wait_q);
1345 } else if (pd->wakeup) {
1346 pd->wakeup(pd->private);
1347 if (dev->port->cad) /* racy but no matter */
1350 printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
1355 * Nobody was waiting, so walk the list to see if anyone is
1356 * interested in being woken up. (Note: no locking required)
1358 /* !!! LOCKING IS NEEDED HERE */
1359 for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1360 if (pd->wakeup && pd != dev)
1361 pd->wakeup(pd->private);
1364 EXPORT_SYMBOL(parport_release);
1366 irqreturn_t parport_irq_handler(int irq, void *dev_id)
1368 struct parport *port = dev_id;
1370 parport_generic_irq(port);
1374 EXPORT_SYMBOL(parport_irq_handler);
1376 MODULE_LICENSE("GPL");