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 regsitered 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)
210 /* There is no actual module called this: you should set
211 * up an alias for modutils. */
212 request_module ("parport_lowlevel");
216 * iterates through all the devices connected to the bus and sends the device
217 * details to the match_port callback of the driver, so that the driver can
218 * know what are all the ports that are connected to the bus and choose the
219 * port to which it wants to register its device.
221 static int port_check(struct device *dev, void *dev_drv)
223 struct parport_driver *drv = dev_drv;
225 /* only send ports, do not send other devices connected to bus */
227 drv->match_port(to_parport_dev(dev));
232 * Iterates through all the devices connected to the bus and return 1
233 * if the device is a parallel port.
236 static int port_detect(struct device *dev, void *dev_drv)
244 * parport_register_driver - register a parallel port device driver
245 * @drv: structure describing the driver
246 * @owner: owner module of drv
247 * @mod_name: module name string
249 * This can be called by a parallel port device driver in order
250 * to receive notifications about ports being found in the
251 * system, as well as ports no longer available.
253 * If devmodel is true then the new device model is used
256 * The @drv structure is allocated by the caller and must not be
257 * deallocated until after calling parport_unregister_driver().
259 * If using the non device model:
260 * The driver's attach() function may block. The port that
261 * attach() is given will be valid for the duration of the
262 * callback, but if the driver wants to take a copy of the
263 * pointer it must call parport_get_port() to do so. Calling
264 * parport_register_device() on that port will do this for you.
266 * The driver's detach() function may block. The port that
267 * detach() is given will be valid for the duration of the
268 * callback, but if the driver wants to take a copy of the
269 * pointer it must call parport_get_port() to do so.
272 * Returns 0 on success. The non device model will always succeeds.
273 * but the new device model can fail and will return the error code.
276 int __parport_register_driver(struct parport_driver *drv, struct module *owner,
277 const char *mod_name)
279 if (list_empty(&portlist))
280 get_lowlevel_driver ();
283 /* using device model */
286 /* initialize common driver fields */
287 drv->driver.name = drv->name;
288 drv->driver.bus = &parport_bus_type;
289 drv->driver.owner = owner;
290 drv->driver.mod_name = mod_name;
291 ret = driver_register(&drv->driver);
296 * check if bus has any parallel port registered, if
297 * none is found then load the lowlevel driver.
299 ret = bus_for_each_dev(&parport_bus_type, NULL, NULL,
302 get_lowlevel_driver();
304 mutex_lock(®istration_lock);
306 bus_for_each_dev(&parport_bus_type, NULL, drv,
308 mutex_unlock(®istration_lock);
310 struct parport *port;
312 drv->devmodel = false;
314 mutex_lock(®istration_lock);
315 list_for_each_entry(port, &portlist, list)
317 list_add(&drv->list, &drivers);
318 mutex_unlock(®istration_lock);
323 EXPORT_SYMBOL(__parport_register_driver);
325 static int port_detach(struct device *dev, void *_drv)
327 struct parport_driver *drv = _drv;
329 if (is_parport(dev) && drv->detach)
330 drv->detach(to_parport_dev(dev));
336 * parport_unregister_driver - deregister a parallel port device driver
337 * @drv: structure describing the driver that was given to
338 * parport_register_driver()
340 * This should be called by a parallel port device driver that
341 * has registered itself using parport_register_driver() when it
342 * is about to be unloaded.
344 * When it returns, the driver's attach() routine will no longer
345 * be called, and for each port that attach() was called for, the
346 * detach() routine will have been called.
348 * All the driver's attach() and detach() calls are guaranteed to have
349 * finished by the time this function returns.
352 void parport_unregister_driver (struct parport_driver *drv)
354 struct parport *port;
356 mutex_lock(®istration_lock);
358 bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
359 driver_unregister(&drv->driver);
361 list_del_init(&drv->list);
362 list_for_each_entry(port, &portlist, list)
365 mutex_unlock(®istration_lock);
368 static void free_port(struct device *dev)
371 struct parport *port = to_parport_dev(dev);
373 spin_lock(&full_list_lock);
374 list_del(&port->full_list);
375 spin_unlock(&full_list_lock);
376 for (d = 0; d < 5; d++) {
377 kfree(port->probe_info[d].class_name);
378 kfree(port->probe_info[d].mfr);
379 kfree(port->probe_info[d].model);
380 kfree(port->probe_info[d].cmdset);
381 kfree(port->probe_info[d].description);
389 * parport_get_port - increment a port's reference count
392 * This ensures that a struct parport pointer remains valid
393 * until the matching parport_put_port() call.
396 struct parport *parport_get_port (struct parport *port)
398 struct device *dev = get_device(&port->bus_dev);
400 return to_parport_dev(dev);
403 void parport_del_port(struct parport *port)
405 device_unregister(&port->bus_dev);
407 EXPORT_SYMBOL(parport_del_port);
410 * parport_put_port - decrement a port's reference count
413 * This should be called once for each call to parport_get_port(),
414 * once the port is no longer needed. When the reference count reaches
415 * zero (port is no longer used), free_port is called.
418 void parport_put_port (struct parport *port)
420 put_device(&port->bus_dev);
424 * parport_register_port - register a parallel port
425 * @base: base I/O address
428 * @ops: pointer to the port driver's port operations structure
430 * When a parallel port (lowlevel) driver finds a port that
431 * should be made available to parallel port device drivers, it
432 * should call parport_register_port(). The @base, @irq, and
433 * @dma parameters are for the convenience of port drivers, and
434 * for ports where they aren't meaningful needn't be set to
435 * anything special. They can be altered afterwards by adjusting
436 * the relevant members of the parport structure that is returned
437 * and represents the port. They should not be tampered with
438 * after calling parport_announce_port, however.
440 * If there are parallel port device drivers in the system that
441 * have registered themselves using parport_register_driver(),
442 * they are not told about the port at this time; that is done by
443 * parport_announce_port().
445 * The @ops structure is allocated by the caller, and must not be
446 * deallocated before calling parport_remove_port().
448 * If there is no memory to allocate a new parport structure,
449 * this function will return %NULL.
452 struct parport *parport_register_port(unsigned long base, int irq, int dma,
453 struct parport_operations *ops)
462 tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
464 printk(KERN_WARNING "parport: memory squeeze\n");
468 /* Init our structure */
472 tmp->muxport = tmp->daisy = tmp->muxsel = -1;
474 INIT_LIST_HEAD(&tmp->list);
475 tmp->devices = tmp->cad = NULL;
479 memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info));
480 rwlock_init(&tmp->cad_lock);
481 spin_lock_init(&tmp->waitlist_lock);
482 spin_lock_init(&tmp->pardevice_lock);
483 tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
484 tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
485 sema_init(&tmp->ieee1284.irq, 0);
486 tmp->spintime = parport_default_spintime;
487 atomic_set (&tmp->ref_count, 1);
488 INIT_LIST_HEAD(&tmp->full_list);
490 name = kmalloc(15, GFP_KERNEL);
492 printk(KERN_ERR "parport: memory squeeze\n");
496 /* Search for the lowest free parport number. */
498 spin_lock(&full_list_lock);
499 for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
500 struct parport *p = list_entry(l, struct parport, full_list);
501 if (p->number != num)
504 tmp->portnum = tmp->number = num;
505 list_add_tail(&tmp->full_list, l);
506 spin_unlock(&full_list_lock);
509 * Now that the portnum is known finish doing the Init.
511 sprintf(name, "parport%d", tmp->portnum = tmp->number);
513 tmp->bus_dev.bus = &parport_bus_type;
514 tmp->bus_dev.release = free_port;
515 dev_set_name(&tmp->bus_dev, name);
516 tmp->bus_dev.type = &parport_device_type;
518 for (device = 0; device < 5; device++)
519 /* assume the worst */
520 tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
522 tmp->waithead = tmp->waittail = NULL;
524 ret = device_register(&tmp->bus_dev);
526 put_device(&tmp->bus_dev);
534 * parport_announce_port - tell device drivers about a parallel port
535 * @port: parallel port to announce
537 * After a port driver has registered a parallel port with
538 * parport_register_port, and performed any necessary
539 * initialisation or adjustments, it should call
540 * parport_announce_port() in order to notify all device drivers
541 * that have called parport_register_driver(). Their attach()
542 * functions will be called, with @port as the parameter.
545 void parport_announce_port (struct parport *port)
549 #ifdef CONFIG_PARPORT_1284
550 /* Analyse the IEEE1284.3 topology of the port. */
551 parport_daisy_init(port);
555 printk(KERN_WARNING "%s: fix this legacy "
556 "no-device port driver!\n",
559 parport_proc_register(port);
560 mutex_lock(®istration_lock);
561 spin_lock_irq(&parportlist_lock);
562 list_add_tail(&port->list, &portlist);
563 for (i = 1; i < 3; i++) {
564 struct parport *slave = port->slaves[i-1];
566 list_add_tail(&slave->list, &portlist);
568 spin_unlock_irq(&parportlist_lock);
570 /* Let drivers know that new port(s) has arrived. */
571 attach_driver_chain (port);
572 for (i = 1; i < 3; i++) {
573 struct parport *slave = port->slaves[i-1];
575 attach_driver_chain(slave);
577 mutex_unlock(®istration_lock);
581 * parport_remove_port - deregister a parallel port
582 * @port: parallel port to deregister
584 * When a parallel port driver is forcibly unloaded, or a
585 * parallel port becomes inaccessible, the port driver must call
586 * this function in order to deal with device drivers that still
589 * The parport structure associated with the port has its
590 * operations structure replaced with one containing 'null'
591 * operations that return errors or just don't do anything.
593 * Any drivers that have registered themselves using
594 * parport_register_driver() are notified that the port is no
595 * longer accessible by having their detach() routines called
596 * with @port as the parameter.
599 void parport_remove_port(struct parport *port)
603 mutex_lock(®istration_lock);
605 /* Spread the word. */
606 detach_driver_chain (port);
608 #ifdef CONFIG_PARPORT_1284
609 /* Forget the IEEE1284.3 topology of the port. */
610 parport_daisy_fini(port);
611 for (i = 1; i < 3; i++) {
612 struct parport *slave = port->slaves[i-1];
615 detach_driver_chain(slave);
616 parport_daisy_fini(slave);
620 port->ops = &dead_ops;
621 spin_lock(&parportlist_lock);
622 list_del_init(&port->list);
623 for (i = 1; i < 3; i++) {
624 struct parport *slave = port->slaves[i-1];
626 list_del_init(&slave->list);
628 spin_unlock(&parportlist_lock);
630 mutex_unlock(®istration_lock);
632 parport_proc_unregister(port);
634 for (i = 1; i < 3; i++) {
635 struct parport *slave = port->slaves[i-1];
637 parport_put_port(slave);
642 * parport_register_device - register a device on a parallel port
643 * @port: port to which the device is attached
644 * @name: a name to refer to the device
645 * @pf: preemption callback
646 * @kf: kick callback (wake-up)
647 * @irq_func: interrupt handler
648 * @flags: registration flags
649 * @handle: data for callback functions
651 * This function, called by parallel port device drivers,
652 * declares that a device is connected to a port, and tells the
653 * system all it needs to know.
655 * The @name is allocated by the caller and must not be
656 * deallocated until the caller calls @parport_unregister_device
659 * The preemption callback function, @pf, is called when this
660 * device driver has claimed access to the port but another
661 * device driver wants to use it. It is given @handle as its
662 * parameter, and should return zero if it is willing for the
663 * system to release the port to another driver on its behalf.
664 * If it wants to keep control of the port it should return
665 * non-zero, and no action will be taken. It is good manners for
666 * the driver to try to release the port at the earliest
667 * opportunity after its preemption callback rejects a preemption
668 * attempt. Note that if a preemption callback is happy for
669 * preemption to go ahead, there is no need to release the port;
670 * it is done automatically. This function may not block, as it
671 * may be called from interrupt context. If the device driver
672 * does not support preemption, @pf can be %NULL.
674 * The wake-up ("kick") callback function, @kf, is called when
675 * the port is available to be claimed for exclusive access; that
676 * is, parport_claim() is guaranteed to succeed when called from
677 * inside the wake-up callback function. If the driver wants to
678 * claim the port it should do so; otherwise, it need not take
679 * any action. This function may not block, as it may be called
680 * from interrupt context. If the device driver does not want to
681 * be explicitly invited to claim the port in this way, @kf can
684 * The interrupt handler, @irq_func, is called when an interrupt
685 * arrives from the parallel port. Note that if a device driver
686 * wants to use interrupts it should use parport_enable_irq(),
687 * and can also check the irq member of the parport structure
688 * representing the port.
690 * The parallel port (lowlevel) driver is the one that has called
691 * request_irq() and whose interrupt handler is called first.
692 * This handler does whatever needs to be done to the hardware to
693 * acknowledge the interrupt (for PC-style ports there is nothing
694 * special to be done). It then tells the IEEE 1284 code about
695 * the interrupt, which may involve reacting to an IEEE 1284
696 * event depending on the current IEEE 1284 phase. After this,
697 * it calls @irq_func. Needless to say, @irq_func will be called
698 * from interrupt context, and may not block.
700 * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
701 * so should only be used when sharing the port with other device
702 * drivers is impossible and would lead to incorrect behaviour.
703 * Use it sparingly! Normally, @flags will be zero.
705 * This function returns a pointer to a structure that represents
706 * the device on the port, or %NULL if there is not enough memory
707 * to allocate space for that structure.
711 parport_register_device(struct parport *port, const char *name,
712 int (*pf)(void *), void (*kf)(void *),
713 void (*irq_func)(void *),
714 int flags, void *handle)
716 struct pardevice *tmp;
718 if (port->physport->flags & PARPORT_FLAG_EXCL) {
719 /* An exclusive device is registered. */
720 printk (KERN_DEBUG "%s: no more devices allowed\n",
725 if (flags & PARPORT_DEV_LURK) {
727 printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
732 if (flags & PARPORT_DEV_EXCL) {
733 if (port->physport->devices) {
735 * If a device is already registered and this new
736 * device wants exclusive access, then no need to
737 * continue as we can not grant exclusive access to
740 pr_err("%s: cannot grant exclusive access for device %s\n",
746 /* We up our own module reference count, and that of the port
747 on which a device is to be registered, to ensure that
748 neither of us gets unloaded while we sleep in (e.g.)
751 if (!try_module_get(port->ops->owner)) {
755 parport_get_port (port);
757 tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
759 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
763 tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
764 if (tmp->state == NULL) {
765 printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
766 goto out_free_pardevice;
774 tmp->private = handle;
776 tmp->irq_func = irq_func;
778 tmp->timeout = 5 * HZ;
779 tmp->devmodel = false;
781 /* Chain this onto the list */
784 * This function must not run from an irq handler so we don' t need
785 * to clear irq on the local CPU. -arca
787 spin_lock(&port->physport->pardevice_lock);
789 if (flags & PARPORT_DEV_EXCL) {
790 if (port->physport->devices) {
791 spin_unlock (&port->physport->pardevice_lock);
793 "%s: cannot grant exclusive access for "
794 "device %s\n", port->name, name);
797 port->flags |= PARPORT_FLAG_EXCL;
800 tmp->next = port->physport->devices;
801 wmb(); /* Make sure that tmp->next is written before it's
802 added to the list; see comments marked 'no locking
804 if (port->physport->devices)
805 port->physport->devices->prev = tmp;
806 port->physport->devices = tmp;
807 spin_unlock(&port->physport->pardevice_lock);
809 init_waitqueue_head(&tmp->wait_q);
810 tmp->timeslice = parport_default_timeslice;
811 tmp->waitnext = tmp->waitprev = NULL;
814 * This has to be run as last thing since init_state may need other
815 * pardevice fields. -arca
817 port->ops->init_state(tmp, tmp->state);
818 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
819 port->proc_device = tmp;
820 parport_device_proc_register(tmp);
829 parport_put_port (port);
830 module_put(port->ops->owner);
835 static void free_pardevice(struct device *dev)
837 struct pardevice *par_dev = to_pardevice(dev);
839 kfree(par_dev->name);
844 parport_register_dev_model(struct parport *port, const char *name,
845 const struct pardev_cb *par_dev_cb, int id)
847 struct pardevice *par_dev;
851 if (port->physport->flags & PARPORT_FLAG_EXCL) {
852 /* An exclusive device is registered. */
853 pr_err("%s: no more devices allowed\n", port->name);
857 if (par_dev_cb->flags & PARPORT_DEV_LURK) {
858 if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
859 pr_info("%s: refused to register lurking device (%s) without callbacks\n",
865 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
866 if (port->physport->devices) {
868 * If a device is already registered and this new
869 * device wants exclusive access, then no need to
870 * continue as we can not grant exclusive access to
873 pr_err("%s: cannot grant exclusive access for device %s\n",
879 if (!try_module_get(port->ops->owner))
882 parport_get_port(port);
884 par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
888 par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
890 goto err_put_par_dev;
892 devname = kstrdup(name, GFP_KERNEL);
894 goto err_free_par_dev;
896 par_dev->name = devname;
897 par_dev->port = port;
899 par_dev->preempt = par_dev_cb->preempt;
900 par_dev->wakeup = par_dev_cb->wakeup;
901 par_dev->private = par_dev_cb->private;
902 par_dev->flags = par_dev_cb->flags;
903 par_dev->irq_func = par_dev_cb->irq_func;
904 par_dev->waiting = 0;
905 par_dev->timeout = 5 * HZ;
907 par_dev->dev.parent = &port->bus_dev;
908 par_dev->dev.bus = &parport_bus_type;
909 ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
911 goto err_free_devname;
912 par_dev->dev.release = free_pardevice;
913 par_dev->devmodel = true;
914 ret = device_register(&par_dev->dev);
916 kfree(par_dev->state);
917 put_device(&par_dev->dev);
921 /* Chain this onto the list */
922 par_dev->prev = NULL;
924 * This function must not run from an irq handler so we don' t need
925 * to clear irq on the local CPU. -arca
927 spin_lock(&port->physport->pardevice_lock);
929 if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
930 if (port->physport->devices) {
931 spin_unlock(&port->physport->pardevice_lock);
932 pr_debug("%s: cannot grant exclusive access for device %s\n",
934 kfree(par_dev->state);
935 device_unregister(&par_dev->dev);
938 port->flags |= PARPORT_FLAG_EXCL;
941 par_dev->next = port->physport->devices;
943 * Make sure that tmp->next is written before it's
944 * added to the list; see comments marked 'no locking
947 if (port->physport->devices)
948 port->physport->devices->prev = par_dev;
949 port->physport->devices = par_dev;
950 spin_unlock(&port->physport->pardevice_lock);
952 init_waitqueue_head(&par_dev->wait_q);
953 par_dev->timeslice = parport_default_timeslice;
954 par_dev->waitnext = NULL;
955 par_dev->waitprev = NULL;
958 * This has to be run as last thing since init_state may need other
959 * pardevice fields. -arca
961 port->ops->init_state(par_dev, par_dev->state);
962 if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
963 port->proc_device = par_dev;
964 parport_device_proc_register(par_dev);
972 kfree(par_dev->state);
974 if (!par_dev->devmodel)
977 parport_put_port(port);
978 module_put(port->ops->owner);
982 EXPORT_SYMBOL(parport_register_dev_model);
985 * parport_unregister_device - deregister a device on a parallel port
986 * @dev: pointer to structure representing device
988 * This undoes the effect of parport_register_device().
991 void parport_unregister_device(struct pardevice *dev)
993 struct parport *port;
995 #ifdef PARPORT_PARANOID
997 printk(KERN_ERR "parport_unregister_device: passed NULL\n");
1002 port = dev->port->physport;
1004 if (port->proc_device == dev) {
1005 port->proc_device = NULL;
1006 clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
1007 parport_device_proc_unregister(dev);
1010 if (port->cad == dev) {
1011 printk(KERN_DEBUG "%s: %s forgot to release port\n",
1012 port->name, dev->name);
1013 parport_release (dev);
1016 spin_lock(&port->pardevice_lock);
1018 dev->next->prev = dev->prev;
1020 dev->prev->next = dev->next;
1022 port->devices = dev->next;
1024 if (dev->flags & PARPORT_DEV_EXCL)
1025 port->flags &= ~PARPORT_FLAG_EXCL;
1027 spin_unlock(&port->pardevice_lock);
1029 /* Make sure we haven't left any pointers around in the wait
1031 spin_lock_irq(&port->waitlist_lock);
1032 if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1034 dev->waitprev->waitnext = dev->waitnext;
1036 port->waithead = dev->waitnext;
1038 dev->waitnext->waitprev = dev->waitprev;
1040 port->waittail = dev->waitprev;
1042 spin_unlock_irq(&port->waitlist_lock);
1046 device_unregister(&dev->dev);
1050 module_put(port->ops->owner);
1051 parport_put_port (port);
1055 * parport_find_number - find a parallel port by number
1056 * @number: parallel port number
1058 * This returns the parallel port with the specified number, or
1059 * %NULL if there is none.
1061 * There is an implicit parport_get_port() done already; to throw
1062 * away the reference to the port that parport_find_number()
1063 * gives you, use parport_put_port().
1066 struct parport *parport_find_number (int number)
1068 struct parport *port, *result = NULL;
1070 if (list_empty(&portlist))
1071 get_lowlevel_driver ();
1073 spin_lock (&parportlist_lock);
1074 list_for_each_entry(port, &portlist, list) {
1075 if (port->number == number) {
1076 result = parport_get_port (port);
1080 spin_unlock (&parportlist_lock);
1085 * parport_find_base - find a parallel port by base address
1086 * @base: base I/O address
1088 * This returns the parallel port with the specified base
1089 * address, or %NULL if there is none.
1091 * There is an implicit parport_get_port() done already; to throw
1092 * away the reference to the port that parport_find_base()
1093 * gives you, use parport_put_port().
1096 struct parport *parport_find_base (unsigned long base)
1098 struct parport *port, *result = NULL;
1100 if (list_empty(&portlist))
1101 get_lowlevel_driver ();
1103 spin_lock (&parportlist_lock);
1104 list_for_each_entry(port, &portlist, list) {
1105 if (port->base == base) {
1106 result = parport_get_port (port);
1110 spin_unlock (&parportlist_lock);
1115 * parport_claim - claim access to a parallel port device
1116 * @dev: pointer to structure representing a device on the port
1118 * This function will not block and so can be used from interrupt
1119 * context. If parport_claim() succeeds in claiming access to
1120 * the port it returns zero and the port is available to use. It
1121 * may fail (returning non-zero) if the port is in use by another
1122 * driver and that driver is not willing to relinquish control of
1126 int parport_claim(struct pardevice *dev)
1128 struct pardevice *oldcad;
1129 struct parport *port = dev->port->physport;
1130 unsigned long flags;
1132 if (port->cad == dev) {
1133 printk(KERN_INFO "%s: %s already owner\n",
1134 dev->port->name,dev->name);
1138 /* Preempt any current device */
1139 write_lock_irqsave (&port->cad_lock, flags);
1140 if ((oldcad = port->cad) != NULL) {
1141 if (oldcad->preempt) {
1142 if (oldcad->preempt(oldcad->private))
1144 port->ops->save_state(port, dev->state);
1148 if (port->cad != oldcad) {
1149 /* I think we'll actually deadlock rather than
1150 get here, but just in case.. */
1152 "%s: %s released port when preempted!\n",
1153 port->name, oldcad->name);
1159 /* Can't fail from now on, so mark ourselves as no longer waiting. */
1160 if (dev->waiting & 1) {
1163 /* Take ourselves out of the wait list again. */
1164 spin_lock_irq (&port->waitlist_lock);
1166 dev->waitprev->waitnext = dev->waitnext;
1168 port->waithead = dev->waitnext;
1170 dev->waitnext->waitprev = dev->waitprev;
1172 port->waittail = dev->waitprev;
1173 spin_unlock_irq (&port->waitlist_lock);
1174 dev->waitprev = dev->waitnext = NULL;
1177 /* Now we do the change of devices */
1180 #ifdef CONFIG_PARPORT_1284
1181 /* If it's a mux port, select it. */
1182 if (dev->port->muxport >= 0) {
1184 port->muxsel = dev->port->muxport;
1187 /* If it's a daisy chain device, select it. */
1188 if (dev->daisy >= 0) {
1189 /* This could be lazier. */
1190 if (!parport_daisy_select (port, dev->daisy,
1191 IEEE1284_MODE_COMPAT))
1192 port->daisy = dev->daisy;
1194 #endif /* IEEE1284.3 support */
1196 /* Restore control registers */
1197 port->ops->restore_state(port, dev->state);
1198 write_unlock_irqrestore(&port->cad_lock, flags);
1199 dev->time = jiffies;
1203 /* If this is the first time we tried to claim the port, register an
1204 interest. This is only allowed for devices sleeping in
1205 parport_claim_or_block(), or those with a wakeup function. */
1207 /* The cad_lock is still held for writing here */
1208 if (dev->waiting & 2 || dev->wakeup) {
1209 spin_lock (&port->waitlist_lock);
1210 if (test_and_set_bit(0, &dev->waiting) == 0) {
1211 /* First add ourselves to the end of the wait list. */
1212 dev->waitnext = NULL;
1213 dev->waitprev = port->waittail;
1214 if (port->waittail) {
1215 port->waittail->waitnext = dev;
1216 port->waittail = dev;
1218 port->waithead = port->waittail = dev;
1220 spin_unlock (&port->waitlist_lock);
1222 write_unlock_irqrestore (&port->cad_lock, flags);
1227 * parport_claim_or_block - claim access to a parallel port device
1228 * @dev: pointer to structure representing a device on the port
1230 * This behaves like parport_claim(), but will block if necessary
1231 * to wait for the port to be free. A return value of 1
1232 * indicates that it slept; 0 means that it succeeded without
1233 * needing to sleep. A negative error code indicates failure.
1236 int parport_claim_or_block(struct pardevice *dev)
1240 /* Signal to parport_claim() that we can wait even without a
1244 /* Try to claim the port. If this fails, we need to sleep. */
1245 r = parport_claim(dev);
1247 #ifdef PARPORT_DEBUG_SHARING
1248 printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1251 * FIXME!!! Use the proper locking for dev->waiting,
1252 * and make this use the "wait_event_interruptible()"
1253 * interfaces. The cli/sti that used to be here
1256 * See also parport_release()
1259 /* If dev->waiting is clear now, an interrupt
1260 gave us the port and we would deadlock if we slept. */
1262 wait_event_interruptible(dev->wait_q,
1264 if (signal_pending (current)) {
1270 #ifdef PARPORT_DEBUG_SHARING
1271 printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1276 #ifdef PARPORT_DEBUG_SHARING
1277 if (dev->port->physport->cad != dev)
1278 printk(KERN_DEBUG "%s: exiting parport_claim_or_block "
1279 "but %s owns port!\n", dev->name,
1280 dev->port->physport->cad ?
1281 dev->port->physport->cad->name:"nobody");
1289 * parport_release - give up access to a parallel port device
1290 * @dev: pointer to structure representing parallel port device
1292 * This function cannot fail, but it should not be called without
1293 * the port claimed. Similarly, if the port is already claimed
1294 * you should not try claiming it again.
1297 void parport_release(struct pardevice *dev)
1299 struct parport *port = dev->port->physport;
1300 struct pardevice *pd;
1301 unsigned long flags;
1303 /* Make sure that dev is the current device */
1304 write_lock_irqsave(&port->cad_lock, flags);
1305 if (port->cad != dev) {
1306 write_unlock_irqrestore (&port->cad_lock, flags);
1307 printk(KERN_WARNING "%s: %s tried to release parport "
1308 "when not owner\n", port->name, dev->name);
1312 #ifdef CONFIG_PARPORT_1284
1313 /* If this is on a mux port, deselect it. */
1314 if (dev->port->muxport >= 0) {
1319 /* If this is a daisy device, deselect it. */
1320 if (dev->daisy >= 0) {
1321 parport_daisy_deselect_all (port);
1327 write_unlock_irqrestore(&port->cad_lock, flags);
1329 /* Save control registers */
1330 port->ops->save_state(port, dev->state);
1332 /* If anybody is waiting, find out who's been there longest and
1333 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);
1350 /* Nobody was waiting, so walk the list to see if anyone is
1351 interested in being woken up. (Note: no locking required) */
1352 /* !!! LOCKING IS NEEDED HERE */
1353 for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) {
1354 if (pd->wakeup && pd != dev)
1355 pd->wakeup(pd->private);
1359 irqreturn_t parport_irq_handler(int irq, void *dev_id)
1361 struct parport *port = dev_id;
1363 parport_generic_irq(port);
1368 /* Exported symbols for modules. */
1370 EXPORT_SYMBOL(parport_claim);
1371 EXPORT_SYMBOL(parport_claim_or_block);
1372 EXPORT_SYMBOL(parport_release);
1373 EXPORT_SYMBOL(parport_register_port);
1374 EXPORT_SYMBOL(parport_announce_port);
1375 EXPORT_SYMBOL(parport_remove_port);
1376 EXPORT_SYMBOL(parport_unregister_driver);
1377 EXPORT_SYMBOL(parport_register_device);
1378 EXPORT_SYMBOL(parport_unregister_device);
1379 EXPORT_SYMBOL(parport_get_port);
1380 EXPORT_SYMBOL(parport_put_port);
1381 EXPORT_SYMBOL(parport_find_number);
1382 EXPORT_SYMBOL(parport_find_base);
1383 EXPORT_SYMBOL(parport_irq_handler);
1385 MODULE_LICENSE("GPL");