Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/parport/share.c b/drivers/parport/share.c
new file mode 100644
index 0000000..ae7becf
--- /dev/null
+++ b/drivers/parport/share.c
@@ -0,0 +1,1014 @@
+/* $Id: parport_share.c,v 1.15 1998/01/11 12:06:17 philip Exp $
+ * Parallel-port resource manager code.
+ *
+ * Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
+ * Tim Waugh <tim@cyberelk.demon.co.uk>
+ * Jose Renau <renau@acm.org>
+ * Philip Blundell <philb@gnu.org>
+ * Andrea Arcangeli
+ *
+ * based on work by Grant Guenther <grant@torque.net>
+ * and Philip Blundell
+ *
+ * Any part of this program may be used in documents licensed under
+ * the GNU Free Documentation License, Version 1.1 or any later version
+ * published by the Free Software Foundation.
+ */
+
+#undef PARPORT_DEBUG_SHARING /* undef for production */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/threads.h>
+#include <linux/parport.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+
+#include <linux/spinlock.h>
+#include <asm/irq.h>
+
+#undef PARPORT_PARANOID
+
+#define PARPORT_DEFAULT_TIMESLICE (HZ/5)
+
+unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
+int parport_default_spintime = DEFAULT_SPIN_TIME;
+
+static LIST_HEAD(portlist);
+static DEFINE_SPINLOCK(parportlist_lock);
+
+/* list of all allocated ports, sorted by ->number */
+static LIST_HEAD(all_ports);
+static DEFINE_SPINLOCK(full_list_lock);
+
+static LIST_HEAD(drivers);
+
+static DECLARE_MUTEX(registration_lock);
+
+/* What you can do to a port that's gone away.. */
+static void dead_write_lines (struct parport *p, unsigned char b){}
+static unsigned char dead_read_lines (struct parport *p) { return 0; }
+static unsigned char dead_frob_lines (struct parport *p, unsigned char b,
+ unsigned char c) { return 0; }
+static void dead_onearg (struct parport *p){}
+static void dead_initstate (struct pardevice *d, struct parport_state *s) { }
+static void dead_state (struct parport *p, struct parport_state *s) { }
+static size_t dead_write (struct parport *p, const void *b, size_t l, int f)
+{ return 0; }
+static size_t dead_read (struct parport *p, void *b, size_t l, int f)
+{ return 0; }
+static struct parport_operations dead_ops = {
+ .write_data = dead_write_lines, /* data */
+ .read_data = dead_read_lines,
+
+ .write_control = dead_write_lines, /* control */
+ .read_control = dead_read_lines,
+ .frob_control = dead_frob_lines,
+
+ .read_status = dead_read_lines, /* status */
+
+ .enable_irq = dead_onearg, /* enable_irq */
+ .disable_irq = dead_onearg, /* disable_irq */
+
+ .data_forward = dead_onearg, /* data_forward */
+ .data_reverse = dead_onearg, /* data_reverse */
+
+ .init_state = dead_initstate, /* init_state */
+ .save_state = dead_state,
+ .restore_state = dead_state,
+
+ .epp_write_data = dead_write, /* epp */
+ .epp_read_data = dead_read,
+ .epp_write_addr = dead_write,
+ .epp_read_addr = dead_read,
+
+ .ecp_write_data = dead_write, /* ecp */
+ .ecp_read_data = dead_read,
+ .ecp_write_addr = dead_write,
+
+ .compat_write_data = dead_write, /* compat */
+ .nibble_read_data = dead_read, /* nibble */
+ .byte_read_data = dead_read, /* byte */
+
+ .owner = NULL,
+};
+
+/* Call attach(port) for each registered driver. */
+static void attach_driver_chain(struct parport *port)
+{
+ /* caller has exclusive registration_lock */
+ struct parport_driver *drv;
+ list_for_each_entry(drv, &drivers, list)
+ drv->attach(port);
+}
+
+/* Call detach(port) for each registered driver. */
+static void detach_driver_chain(struct parport *port)
+{
+ struct parport_driver *drv;
+ /* caller has exclusive registration_lock */
+ list_for_each_entry(drv, &drivers, list)
+ drv->detach (port);
+}
+
+/* Ask kmod for some lowlevel drivers. */
+static void get_lowlevel_driver (void)
+{
+ /* There is no actual module called this: you should set
+ * up an alias for modutils. */
+ request_module ("parport_lowlevel");
+}
+
+/**
+ * parport_register_driver - register a parallel port device driver
+ * @drv: structure describing the driver
+ *
+ * This can be called by a parallel port device driver in order
+ * to receive notifications about ports being found in the
+ * system, as well as ports no longer available.
+ *
+ * The @drv structure is allocated by the caller and must not be
+ * deallocated until after calling parport_unregister_driver().
+ *
+ * The driver's attach() function may block. The port that
+ * attach() is given will be valid for the duration of the
+ * callback, but if the driver wants to take a copy of the
+ * pointer it must call parport_get_port() to do so. Calling
+ * parport_register_device() on that port will do this for you.
+ *
+ * The driver's detach() function may block. The port that
+ * detach() is given will be valid for the duration of the
+ * callback, but if the driver wants to take a copy of the
+ * pointer it must call parport_get_port() to do so.
+ *
+ * Returns 0 on success. Currently it always succeeds.
+ **/
+
+int parport_register_driver (struct parport_driver *drv)
+{
+ struct parport *port;
+
+ if (list_empty(&portlist))
+ get_lowlevel_driver ();
+
+ down(®istration_lock);
+ list_for_each_entry(port, &portlist, list)
+ drv->attach(port);
+ list_add(&drv->list, &drivers);
+ up(®istration_lock);
+
+ return 0;
+}
+
+/**
+ * parport_unregister_driver - deregister a parallel port device driver
+ * @drv: structure describing the driver that was given to
+ * parport_register_driver()
+ *
+ * This should be called by a parallel port device driver that
+ * has registered itself using parport_register_driver() when it
+ * is about to be unloaded.
+ *
+ * When it returns, the driver's attach() routine will no longer
+ * be called, and for each port that attach() was called for, the
+ * detach() routine will have been called.
+ *
+ * All the driver's attach() and detach() calls are guaranteed to have
+ * finished by the time this function returns.
+ **/
+
+void parport_unregister_driver (struct parport_driver *drv)
+{
+ struct parport *port;
+
+ down(®istration_lock);
+ list_del_init(&drv->list);
+ list_for_each_entry(port, &portlist, list)
+ drv->detach(port);
+ up(®istration_lock);
+}
+
+static void free_port (struct parport *port)
+{
+ int d;
+ spin_lock(&full_list_lock);
+ list_del(&port->full_list);
+ spin_unlock(&full_list_lock);
+ for (d = 0; d < 5; d++) {
+ if (port->probe_info[d].class_name)
+ kfree (port->probe_info[d].class_name);
+ if (port->probe_info[d].mfr)
+ kfree (port->probe_info[d].mfr);
+ if (port->probe_info[d].model)
+ kfree (port->probe_info[d].model);
+ if (port->probe_info[d].cmdset)
+ kfree (port->probe_info[d].cmdset);
+ if (port->probe_info[d].description)
+ kfree (port->probe_info[d].description);
+ }
+
+ kfree(port->name);
+ kfree(port);
+}
+
+/**
+ * parport_get_port - increment a port's reference count
+ * @port: the port
+ *
+ * This ensure's that a struct parport pointer remains valid
+ * until the matching parport_put_port() call.
+ **/
+
+struct parport *parport_get_port (struct parport *port)
+{
+ atomic_inc (&port->ref_count);
+ return port;
+}
+
+/**
+ * parport_put_port - decrement a port's reference count
+ * @port: the port
+ *
+ * This should be called once for each call to parport_get_port(),
+ * once the port is no longer needed.
+ **/
+
+void parport_put_port (struct parport *port)
+{
+ if (atomic_dec_and_test (&port->ref_count))
+ /* Can destroy it now. */
+ free_port (port);
+
+ return;
+}
+
+/**
+ * parport_register_port - register a parallel port
+ * @base: base I/O address
+ * @irq: IRQ line
+ * @dma: DMA channel
+ * @ops: pointer to the port driver's port operations structure
+ *
+ * When a parallel port (lowlevel) driver finds a port that
+ * should be made available to parallel port device drivers, it
+ * should call parport_register_port(). The @base, @irq, and
+ * @dma parameters are for the convenience of port drivers, and
+ * for ports where they aren't meaningful needn't be set to
+ * anything special. They can be altered afterwards by adjusting
+ * the relevant members of the parport structure that is returned
+ * and represents the port. They should not be tampered with
+ * after calling parport_announce_port, however.
+ *
+ * If there are parallel port device drivers in the system that
+ * have registered themselves using parport_register_driver(),
+ * they are not told about the port at this time; that is done by
+ * parport_announce_port().
+ *
+ * The @ops structure is allocated by the caller, and must not be
+ * deallocated before calling parport_remove_port().
+ *
+ * If there is no memory to allocate a new parport structure,
+ * this function will return %NULL.
+ **/
+
+struct parport *parport_register_port(unsigned long base, int irq, int dma,
+ struct parport_operations *ops)
+{
+ struct list_head *l;
+ struct parport *tmp;
+ int num;
+ int device;
+ char *name;
+
+ tmp = kmalloc(sizeof(struct parport), GFP_KERNEL);
+ if (!tmp) {
+ printk(KERN_WARNING "parport: memory squeeze\n");
+ return NULL;
+ }
+
+ /* Init our structure */
+ memset(tmp, 0, sizeof(struct parport));
+ tmp->base = base;
+ tmp->irq = irq;
+ tmp->dma = dma;
+ tmp->muxport = tmp->daisy = tmp->muxsel = -1;
+ tmp->modes = 0;
+ INIT_LIST_HEAD(&tmp->list);
+ tmp->devices = tmp->cad = NULL;
+ tmp->flags = 0;
+ tmp->ops = ops;
+ tmp->physport = tmp;
+ memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info));
+ rwlock_init(&tmp->cad_lock);
+ spin_lock_init(&tmp->waitlist_lock);
+ spin_lock_init(&tmp->pardevice_lock);
+ tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
+ tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
+ init_MUTEX_LOCKED (&tmp->ieee1284.irq); /* actually a semaphore at 0 */
+ tmp->spintime = parport_default_spintime;
+ atomic_set (&tmp->ref_count, 1);
+ INIT_LIST_HEAD(&tmp->full_list);
+
+ name = kmalloc(15, GFP_KERNEL);
+ if (!name) {
+ printk(KERN_ERR "parport: memory squeeze\n");
+ kfree(tmp);
+ return NULL;
+ }
+ /* Search for the lowest free parport number. */
+
+ spin_lock(&full_list_lock);
+ for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
+ struct parport *p = list_entry(l, struct parport, full_list);
+ if (p->number != num)
+ break;
+ }
+ tmp->portnum = tmp->number = num;
+ list_add_tail(&tmp->full_list, l);
+ spin_unlock(&full_list_lock);
+
+ /*
+ * Now that the portnum is known finish doing the Init.
+ */
+ sprintf(name, "parport%d", tmp->portnum = tmp->number);
+ tmp->name = name;
+
+ for (device = 0; device < 5; device++)
+ /* assume the worst */
+ tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
+
+ tmp->waithead = tmp->waittail = NULL;
+
+ return tmp;
+}
+
+/**
+ * parport_announce_port - tell device drivers about a parallel port
+ * @port: parallel port to announce
+ *
+ * After a port driver has registered a parallel port with
+ * parport_register_port, and performed any necessary
+ * initialisation or adjustments, it should call
+ * parport_announce_port() in order to notify all device drivers
+ * that have called parport_register_driver(). Their attach()
+ * functions will be called, with @port as the parameter.
+ **/
+
+void parport_announce_port (struct parport *port)
+{
+ int i;
+
+#ifdef CONFIG_PARPORT_1284
+ /* Analyse the IEEE1284.3 topology of the port. */
+ parport_daisy_init(port);
+#endif
+
+ parport_proc_register(port);
+ down(®istration_lock);
+ spin_lock_irq(&parportlist_lock);
+ list_add_tail(&port->list, &portlist);
+ for (i = 1; i < 3; i++) {
+ struct parport *slave = port->slaves[i-1];
+ if (slave)
+ list_add_tail(&slave->list, &portlist);
+ }
+ spin_unlock_irq(&parportlist_lock);
+
+ /* Let drivers know that new port(s) has arrived. */
+ attach_driver_chain (port);
+ for (i = 1; i < 3; i++) {
+ struct parport *slave = port->slaves[i-1];
+ if (slave)
+ attach_driver_chain(slave);
+ }
+ up(®istration_lock);
+}
+
+/**
+ * parport_remove_port - deregister a parallel port
+ * @port: parallel port to deregister
+ *
+ * When a parallel port driver is forcibly unloaded, or a
+ * parallel port becomes inaccessible, the port driver must call
+ * this function in order to deal with device drivers that still
+ * want to use it.
+ *
+ * The parport structure associated with the port has its
+ * operations structure replaced with one containing 'null'
+ * operations that return errors or just don't do anything.
+ *
+ * Any drivers that have registered themselves using
+ * parport_register_driver() are notified that the port is no
+ * longer accessible by having their detach() routines called
+ * with @port as the parameter.
+ **/
+
+void parport_remove_port(struct parport *port)
+{
+ int i;
+
+ down(®istration_lock);
+
+ /* Spread the word. */
+ detach_driver_chain (port);
+
+#ifdef CONFIG_PARPORT_1284
+ /* Forget the IEEE1284.3 topology of the port. */
+ parport_daisy_fini(port);
+ for (i = 1; i < 3; i++) {
+ struct parport *slave = port->slaves[i-1];
+ if (!slave)
+ continue;
+ detach_driver_chain(slave);
+ parport_daisy_fini(slave);
+ }
+#endif
+
+ port->ops = &dead_ops;
+ spin_lock(&parportlist_lock);
+ list_del_init(&port->list);
+ for (i = 1; i < 3; i++) {
+ struct parport *slave = port->slaves[i-1];
+ if (slave)
+ list_del_init(&slave->list);
+ }
+ spin_unlock(&parportlist_lock);
+
+ up(®istration_lock);
+
+ parport_proc_unregister(port);
+
+ for (i = 1; i < 3; i++) {
+ struct parport *slave = port->slaves[i-1];
+ if (slave)
+ parport_put_port(slave);
+ }
+}
+
+/**
+ * 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)(int, void *, struct pt_regs *),
+ 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) {
+ printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\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 == NULL) {
+ printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
+ goto out;
+ }
+
+ tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
+ if (tmp->state == NULL) {
+ printk(KERN_WARNING "%s: memory squeeze, couldn't register %s.\n", port->name, name);
+ 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;
+
+ /* 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);
+ 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;
+}
+
+/**
+ * parport_unregister_device - deregister a device on a parallel port
+ * @dev: pointer to structure representing device
+ *
+ * This undoes the effect of parport_register_device().
+ **/
+
+void parport_unregister_device(struct pardevice *dev)
+{
+ struct parport *port;
+
+#ifdef PARPORT_PARANOID
+ if (dev == NULL) {
+ printk(KERN_ERR "parport_unregister_device: passed NULL\n");
+ return;
+ }
+#endif
+
+ parport_device_proc_unregister(dev);
+
+ port = dev->port->physport;
+
+ if (port->cad == dev) {
+ printk(KERN_DEBUG "%s: %s forgot to release port\n",
+ port->name, dev->name);
+ parport_release (dev);
+ }
+
+ spin_lock(&port->pardevice_lock);
+ if (dev->next)
+ dev->next->prev = dev->prev;
+ if (dev->prev)
+ dev->prev->next = dev->next;
+ else
+ port->devices = dev->next;
+
+ if (dev->flags & PARPORT_DEV_EXCL)
+ port->flags &= ~PARPORT_FLAG_EXCL;
+
+ spin_unlock(&port->pardevice_lock);
+
+ /* Make sure we haven't left any pointers around in the wait
+ * list. */
+ spin_lock (&port->waitlist_lock);
+ if (dev->waitprev || dev->waitnext || port->waithead == dev) {
+ if (dev->waitprev)
+ dev->waitprev->waitnext = dev->waitnext;
+ else
+ port->waithead = dev->waitnext;
+ if (dev->waitnext)
+ dev->waitnext->waitprev = dev->waitprev;
+ else
+ port->waittail = dev->waitprev;
+ }
+ spin_unlock (&port->waitlist_lock);
+
+ kfree(dev->state);
+ kfree(dev);
+
+ module_put(port->ops->owner);
+ parport_put_port (port);
+}
+
+/**
+ * parport_find_number - find a parallel port by number
+ * @number: parallel port number
+ *
+ * This returns the parallel port with the specified number, or
+ * %NULL if there is none.
+ *
+ * There is an implicit parport_get_port() done already; to throw
+ * away the reference to the port that parport_find_number()
+ * gives you, use parport_put_port().
+ */
+
+struct parport *parport_find_number (int number)
+{
+ struct parport *port, *result = NULL;
+
+ if (list_empty(&portlist))
+ get_lowlevel_driver ();
+
+ spin_lock (&parportlist_lock);
+ list_for_each_entry(port, &portlist, list) {
+ if (port->number == number) {
+ result = parport_get_port (port);
+ break;
+ }
+ }
+ spin_unlock (&parportlist_lock);
+ return result;
+}
+
+/**
+ * parport_find_base - find a parallel port by base address
+ * @base: base I/O address
+ *
+ * This returns the parallel port with the specified base
+ * address, or %NULL if there is none.
+ *
+ * There is an implicit parport_get_port() done already; to throw
+ * away the reference to the port that parport_find_base()
+ * gives you, use parport_put_port().
+ */
+
+struct parport *parport_find_base (unsigned long base)
+{
+ struct parport *port, *result = NULL;
+
+ if (list_empty(&portlist))
+ get_lowlevel_driver ();
+
+ spin_lock (&parportlist_lock);
+ list_for_each_entry(port, &portlist, list) {
+ if (port->base == base) {
+ result = parport_get_port (port);
+ break;
+ }
+ }
+ spin_unlock (&parportlist_lock);
+ return result;
+}
+
+/**
+ * parport_claim - claim access to a parallel port device
+ * @dev: pointer to structure representing a device on the port
+ *
+ * This function will not block and so can be used from interrupt
+ * context. If parport_claim() succeeds in claiming access to
+ * the port it returns zero and the port is available to use. It
+ * may fail (returning non-zero) if the port is in use by another
+ * driver and that driver is not willing to relinquish control of
+ * the port.
+ **/
+
+int parport_claim(struct pardevice *dev)
+{
+ struct pardevice *oldcad;
+ struct parport *port = dev->port->physport;
+ unsigned long flags;
+
+ if (port->cad == dev) {
+ printk(KERN_INFO "%s: %s already owner\n",
+ dev->port->name,dev->name);
+ return 0;
+ }
+
+ /* Preempt any current device */
+ write_lock_irqsave (&port->cad_lock, flags);
+ if ((oldcad = port->cad) != NULL) {
+ if (oldcad->preempt) {
+ if (oldcad->preempt(oldcad->private))
+ goto blocked;
+ port->ops->save_state(port, dev->state);
+ } else
+ goto blocked;
+
+ if (port->cad != oldcad) {
+ /* I think we'll actually deadlock rather than
+ get here, but just in case.. */
+ printk(KERN_WARNING
+ "%s: %s released port when preempted!\n",
+ port->name, oldcad->name);
+ if (port->cad)
+ goto blocked;
+ }
+ }
+
+ /* Can't fail from now on, so mark ourselves as no longer waiting. */
+ if (dev->waiting & 1) {
+ dev->waiting = 0;
+
+ /* Take ourselves out of the wait list again. */
+ spin_lock_irq (&port->waitlist_lock);
+ if (dev->waitprev)
+ dev->waitprev->waitnext = dev->waitnext;
+ else
+ port->waithead = dev->waitnext;
+ if (dev->waitnext)
+ dev->waitnext->waitprev = dev->waitprev;
+ else
+ port->waittail = dev->waitprev;
+ spin_unlock_irq (&port->waitlist_lock);
+ dev->waitprev = dev->waitnext = NULL;
+ }
+
+ /* Now we do the change of devices */
+ port->cad = dev;
+
+#ifdef CONFIG_PARPORT_1284
+ /* If it's a mux port, select it. */
+ if (dev->port->muxport >= 0) {
+ /* FIXME */
+ port->muxsel = dev->port->muxport;
+ }
+
+ /* If it's a daisy chain device, select it. */
+ if (dev->daisy >= 0) {
+ /* This could be lazier. */
+ if (!parport_daisy_select (port, dev->daisy,
+ IEEE1284_MODE_COMPAT))
+ port->daisy = dev->daisy;
+ }
+#endif /* IEEE1284.3 support */
+
+ /* Restore control registers */
+ port->ops->restore_state(port, dev->state);
+ write_unlock_irqrestore(&port->cad_lock, flags);
+ dev->time = jiffies;
+ return 0;
+
+blocked:
+ /* If this is the first time we tried to claim the port, register an
+ interest. This is only allowed for devices sleeping in
+ parport_claim_or_block(), or those with a wakeup function. */
+
+ /* The cad_lock is still held for writing here */
+ if (dev->waiting & 2 || dev->wakeup) {
+ spin_lock (&port->waitlist_lock);
+ if (test_and_set_bit(0, &dev->waiting) == 0) {
+ /* First add ourselves to the end of the wait list. */
+ dev->waitnext = NULL;
+ dev->waitprev = port->waittail;
+ if (port->waittail) {
+ port->waittail->waitnext = dev;
+ port->waittail = dev;
+ } else
+ port->waithead = port->waittail = dev;
+ }
+ spin_unlock (&port->waitlist_lock);
+ }
+ write_unlock_irqrestore (&port->cad_lock, flags);
+ return -EAGAIN;
+}
+
+/**
+ * parport_claim_or_block - claim access to a parallel port device
+ * @dev: pointer to structure representing a device on the port
+ *
+ * This behaves like parport_claim(), but will block if necessary
+ * to wait for the port to be free. A return value of 1
+ * indicates that it slept; 0 means that it succeeded without
+ * needing to sleep. A negative error code indicates failure.
+ **/
+
+int parport_claim_or_block(struct pardevice *dev)
+{
+ int r;
+
+ /* Signal to parport_claim() that we can wait even without a
+ wakeup function. */
+ dev->waiting = 2;
+
+ /* Try to claim the port. If this fails, we need to sleep. */
+ r = parport_claim(dev);
+ if (r == -EAGAIN) {
+#ifdef PARPORT_DEBUG_SHARING
+ printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
+#endif
+ /*
+ * FIXME!!! Use the proper locking for dev->waiting,
+ * and make this use the "wait_event_interruptible()"
+ * interfaces. The cli/sti that used to be here
+ * did nothing.
+ *
+ * See also parport_release()
+ */
+
+ /* If dev->waiting is clear now, an interrupt
+ gave us the port and we would deadlock if we slept. */
+ if (dev->waiting) {
+ interruptible_sleep_on (&dev->wait_q);
+ if (signal_pending (current)) {
+ return -EINTR;
+ }
+ r = 1;
+ } else {
+ r = 0;
+#ifdef PARPORT_DEBUG_SHARING
+ printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
+ dev->name);
+#endif
+ }
+
+#ifdef PARPORT_DEBUG_SHARING
+ if (dev->port->physport->cad != dev)
+ printk(KERN_DEBUG "%s: exiting parport_claim_or_block "
+ "but %s owns port!\n", dev->name,
+ dev->port->physport->cad ?
+ dev->port->physport->cad->name:"nobody");
+#endif
+ }
+ dev->waiting = 0;
+ return r;
+}
+
+/**
+ * parport_release - give up access to a parallel port device
+ * @dev: pointer to structure representing parallel port device
+ *
+ * This function cannot fail, but it should not be called without
+ * the port claimed. Similarly, if the port is already claimed
+ * you should not try claiming it again.
+ **/
+
+void parport_release(struct pardevice *dev)
+{
+ struct parport *port = dev->port->physport;
+ struct pardevice *pd;
+ unsigned long flags;
+
+ /* Make sure that dev is the current device */
+ write_lock_irqsave(&port->cad_lock, flags);
+ if (port->cad != dev) {
+ write_unlock_irqrestore (&port->cad_lock, flags);
+ printk(KERN_WARNING "%s: %s tried to release parport "
+ "when not owner\n", port->name, dev->name);
+ return;
+ }
+
+#ifdef CONFIG_PARPORT_1284
+ /* If this is on a mux port, deselect it. */
+ if (dev->port->muxport >= 0) {
+ /* FIXME */
+ port->muxsel = -1;
+ }
+
+ /* If this is a daisy device, deselect it. */
+ if (dev->daisy >= 0) {
+ parport_daisy_deselect_all (port);
+ port->daisy = -1;
+ }
+#endif
+
+ port->cad = NULL;
+ write_unlock_irqrestore(&port->cad_lock, flags);
+
+ /* Save control registers */
+ port->ops->save_state(port, dev->state);
+
+ /* If anybody is waiting, find out who's been there longest and
+ then wake them up. (Note: no locking required) */
+ /* !!! LOCKING IS NEEDED HERE */
+ for (pd = port->waithead; pd; pd = pd->waitnext) {
+ if (pd->waiting & 2) { /* sleeping in claim_or_block */
+ parport_claim(pd);
+ if (waitqueue_active(&pd->wait_q))
+ wake_up_interruptible(&pd->wait_q);
+ return;
+ } else if (pd->wakeup) {
+ pd->wakeup(pd->private);
+ if (dev->port->cad) /* racy but no matter */
+ return;
+ } else {
+ printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
+ }
+ }
+
+ /* Nobody was waiting, so walk the list to see if anyone is
+ interested in being woken up. (Note: no locking required) */
+ /* !!! LOCKING IS NEEDED HERE */
+ for (pd = port->devices; (port->cad == NULL) && pd; pd = pd->next) {
+ if (pd->wakeup && pd != dev)
+ pd->wakeup(pd->private);
+ }
+}
+
+/* Exported symbols for modules. */
+
+EXPORT_SYMBOL(parport_claim);
+EXPORT_SYMBOL(parport_claim_or_block);
+EXPORT_SYMBOL(parport_release);
+EXPORT_SYMBOL(parport_register_port);
+EXPORT_SYMBOL(parport_announce_port);
+EXPORT_SYMBOL(parport_remove_port);
+EXPORT_SYMBOL(parport_register_driver);
+EXPORT_SYMBOL(parport_unregister_driver);
+EXPORT_SYMBOL(parport_register_device);
+EXPORT_SYMBOL(parport_unregister_device);
+EXPORT_SYMBOL(parport_put_port);
+EXPORT_SYMBOL(parport_find_number);
+EXPORT_SYMBOL(parport_find_base);
+
+MODULE_LICENSE("GPL");