}
EXPORT_SYMBOL(parport_remove_port);
-/**
- * parport_register_device - register a device on a parallel port
- * @port: port to which the device is attached
- * @name: a name to refer to the device
- * @pf: preemption callback
- * @kf: kick callback (wake-up)
- * @irq_func: interrupt handler
- * @flags: registration flags
- * @handle: data for callback functions
- *
- * This function, called by parallel port device drivers,
- * declares that a device is connected to a port, and tells the
- * system all it needs to know.
- *
- * The @name is allocated by the caller and must not be
- * deallocated until the caller calls @parport_unregister_device
- * for that device.
- *
- * The preemption callback function, @pf, is called when this
- * device driver has claimed access to the port but another
- * device driver wants to use it. It is given @handle as its
- * parameter, and should return zero if it is willing for the
- * system to release the port to another driver on its behalf.
- * If it wants to keep control of the port it should return
- * non-zero, and no action will be taken. It is good manners for
- * the driver to try to release the port at the earliest
- * opportunity after its preemption callback rejects a preemption
- * attempt. Note that if a preemption callback is happy for
- * preemption to go ahead, there is no need to release the port;
- * it is done automatically. This function may not block, as it
- * may be called from interrupt context. If the device driver
- * does not support preemption, @pf can be %NULL.
- *
- * The wake-up ("kick") callback function, @kf, is called when
- * the port is available to be claimed for exclusive access; that
- * is, parport_claim() is guaranteed to succeed when called from
- * inside the wake-up callback function. If the driver wants to
- * claim the port it should do so; otherwise, it need not take
- * any action. This function may not block, as it may be called
- * from interrupt context. If the device driver does not want to
- * be explicitly invited to claim the port in this way, @kf can
- * be %NULL.
- *
- * The interrupt handler, @irq_func, is called when an interrupt
- * arrives from the parallel port. Note that if a device driver
- * wants to use interrupts it should use parport_enable_irq(),
- * and can also check the irq member of the parport structure
- * representing the port.
- *
- * The parallel port (lowlevel) driver is the one that has called
- * request_irq() and whose interrupt handler is called first.
- * This handler does whatever needs to be done to the hardware to
- * acknowledge the interrupt (for PC-style ports there is nothing
- * special to be done). It then tells the IEEE 1284 code about
- * the interrupt, which may involve reacting to an IEEE 1284
- * event depending on the current IEEE 1284 phase. After this,
- * it calls @irq_func. Needless to say, @irq_func will be called
- * from interrupt context, and may not block.
- *
- * The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
- * so should only be used when sharing the port with other device
- * drivers is impossible and would lead to incorrect behaviour.
- * Use it sparingly! Normally, @flags will be zero.
- *
- * This function returns a pointer to a structure that represents
- * the device on the port, or %NULL if there is not enough memory
- * to allocate space for that structure.
- **/
-
-struct pardevice *
-parport_register_device(struct parport *port, const char *name,
- int (*pf)(void *), void (*kf)(void *),
- void (*irq_func)(void *),
- int flags, void *handle)
-{
- struct pardevice *tmp;
-
- if (port->physport->flags & PARPORT_FLAG_EXCL) {
- /* An exclusive device is registered. */
- printk(KERN_DEBUG "%s: no more devices allowed\n", port->name);
- return NULL;
- }
-
- if (flags & PARPORT_DEV_LURK) {
- if (!pf || !kf) {
- pr_info("%s: refused to register lurking device (%s) without callbacks\n",
- port->name, name);
- return NULL;
- }
- }
-
- if (flags & PARPORT_DEV_EXCL) {
- if (port->physport->devices) {
- /*
- * If a device is already registered and this new
- * device wants exclusive access, then no need to
- * continue as we can not grant exclusive access to
- * this device.
- */
- pr_err("%s: cannot grant exclusive access for device %s\n",
- port->name, name);
- return NULL;
- }
- }
-
- /*
- * We up our own module reference count, and that of the port
- * on which a device is to be registered, to ensure that
- * neither of us gets unloaded while we sleep in (e.g.)
- * kmalloc.
- */
- if (!try_module_get(port->ops->owner))
- return NULL;
-
- parport_get_port(port);
-
- tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
- if (!tmp)
- goto out;
-
- tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
- if (!tmp->state)
- goto out_free_pardevice;
-
- tmp->name = name;
- tmp->port = port;
- tmp->daisy = -1;
- tmp->preempt = pf;
- tmp->wakeup = kf;
- tmp->private = handle;
- tmp->flags = flags;
- tmp->irq_func = irq_func;
- tmp->waiting = 0;
- tmp->timeout = 5 * HZ;
- tmp->devmodel = false;
-
- /* Chain this onto the list */
- tmp->prev = NULL;
- /*
- * This function must not run from an irq handler so we don' t need
- * to clear irq on the local CPU. -arca
- */
- spin_lock(&port->physport->pardevice_lock);
-
- if (flags & PARPORT_DEV_EXCL) {
- if (port->physport->devices) {
- spin_unlock(&port->physport->pardevice_lock);
- printk(KERN_DEBUG "%s: cannot grant exclusive access for device %s\n",
- port->name, name);
- goto out_free_all;
- }
- port->flags |= PARPORT_FLAG_EXCL;
- }
-
- tmp->next = port->physport->devices;
- wmb(); /*
- * Make sure that tmp->next is written before it's
- * added to the list; see comments marked 'no locking
- * required'
- */
- if (port->physport->devices)
- port->physport->devices->prev = tmp;
- port->physport->devices = tmp;
- spin_unlock(&port->physport->pardevice_lock);
-
- init_waitqueue_head(&tmp->wait_q);
- tmp->timeslice = parport_default_timeslice;
- tmp->waitnext = tmp->waitprev = NULL;
-
- /*
- * This has to be run as last thing since init_state may need other
- * pardevice fields. -arca
- */
- port->ops->init_state(tmp, tmp->state);
- if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
- port->proc_device = tmp;
- parport_device_proc_register(tmp);
- }
- return tmp;
-
- out_free_all:
- kfree(tmp->state);
- out_free_pardevice:
- kfree(tmp);
- out:
- parport_put_port(port);
- module_put(port->ops->owner);
-
- return NULL;
-}
-EXPORT_SYMBOL(parport_register_device);
-
static void free_pardevice(struct device *dev)
{
struct pardevice *par_dev = to_pardevice(dev);
projects / linux.git / commitdiff