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![Alexandru Gheorghiu](/assets/img/avatar_default.png)
Replaced calls to kmalloc and memset with kzalloc. Patch found using coccinelle. Signed-off-by: Alexandru Gheorghiu <gheorghiuandru@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1031 lines
29 KiB
C
1031 lines
29 KiB
C
/*
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* Parallel-port resource manager code.
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*
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* Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
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* Tim Waugh <tim@cyberelk.demon.co.uk>
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* Jose Renau <renau@acm.org>
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* Philip Blundell <philb@gnu.org>
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* Andrea Arcangeli
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*
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* based on work by Grant Guenther <grant@torque.net>
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* and Philip Blundell
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*
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* Any part of this program may be used in documents licensed under
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* the GNU Free Documentation License, Version 1.1 or any later version
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* published by the Free Software Foundation.
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*/
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#undef PARPORT_DEBUG_SHARING /* undef for production */
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/threads.h>
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#include <linux/parport.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/kmod.h>
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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#include <asm/irq.h>
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#undef PARPORT_PARANOID
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#define PARPORT_DEFAULT_TIMESLICE (HZ/5)
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unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
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int parport_default_spintime = DEFAULT_SPIN_TIME;
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static LIST_HEAD(portlist);
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static DEFINE_SPINLOCK(parportlist_lock);
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/* list of all allocated ports, sorted by ->number */
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static LIST_HEAD(all_ports);
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static DEFINE_SPINLOCK(full_list_lock);
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static LIST_HEAD(drivers);
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static DEFINE_MUTEX(registration_lock);
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/* What you can do to a port that's gone away.. */
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static void dead_write_lines (struct parport *p, unsigned char b){}
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static unsigned char dead_read_lines (struct parport *p) { return 0; }
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static unsigned char dead_frob_lines (struct parport *p, unsigned char b,
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unsigned char c) { return 0; }
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static void dead_onearg (struct parport *p){}
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static void dead_initstate (struct pardevice *d, struct parport_state *s) { }
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static void dead_state (struct parport *p, struct parport_state *s) { }
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static size_t dead_write (struct parport *p, const void *b, size_t l, int f)
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{ return 0; }
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static size_t dead_read (struct parport *p, void *b, size_t l, int f)
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{ return 0; }
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static struct parport_operations dead_ops = {
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.write_data = dead_write_lines, /* data */
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.read_data = dead_read_lines,
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.write_control = dead_write_lines, /* control */
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.read_control = dead_read_lines,
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.frob_control = dead_frob_lines,
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.read_status = dead_read_lines, /* status */
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.enable_irq = dead_onearg, /* enable_irq */
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.disable_irq = dead_onearg, /* disable_irq */
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.data_forward = dead_onearg, /* data_forward */
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.data_reverse = dead_onearg, /* data_reverse */
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.init_state = dead_initstate, /* init_state */
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.save_state = dead_state,
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.restore_state = dead_state,
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.epp_write_data = dead_write, /* epp */
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.epp_read_data = dead_read,
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.epp_write_addr = dead_write,
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.epp_read_addr = dead_read,
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.ecp_write_data = dead_write, /* ecp */
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.ecp_read_data = dead_read,
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.ecp_write_addr = dead_write,
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.compat_write_data = dead_write, /* compat */
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.nibble_read_data = dead_read, /* nibble */
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.byte_read_data = dead_read, /* byte */
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.owner = NULL,
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};
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/* Call attach(port) for each registered driver. */
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static void attach_driver_chain(struct parport *port)
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{
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/* caller has exclusive registration_lock */
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struct parport_driver *drv;
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list_for_each_entry(drv, &drivers, list)
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drv->attach(port);
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}
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/* Call detach(port) for each registered driver. */
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static void detach_driver_chain(struct parport *port)
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{
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struct parport_driver *drv;
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/* caller has exclusive registration_lock */
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list_for_each_entry(drv, &drivers, list)
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drv->detach (port);
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}
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/* Ask kmod for some lowlevel drivers. */
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static void get_lowlevel_driver (void)
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{
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/* There is no actual module called this: you should set
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* up an alias for modutils. */
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request_module ("parport_lowlevel");
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}
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/**
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* parport_register_driver - register a parallel port device driver
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* @drv: structure describing the driver
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*
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* This can be called by a parallel port device driver in order
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* to receive notifications about ports being found in the
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* system, as well as ports no longer available.
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*
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* The @drv structure is allocated by the caller and must not be
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* deallocated until after calling parport_unregister_driver().
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*
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* The driver's attach() function may block. The port that
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* attach() is given will be valid for the duration of the
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* callback, but if the driver wants to take a copy of the
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* pointer it must call parport_get_port() to do so. Calling
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* parport_register_device() on that port will do this for you.
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*
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* The driver's detach() function may block. The port that
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* detach() is given will be valid for the duration of the
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* callback, but if the driver wants to take a copy of the
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* pointer it must call parport_get_port() to do so.
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*
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* Returns 0 on success. Currently it always succeeds.
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**/
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int parport_register_driver (struct parport_driver *drv)
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{
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struct parport *port;
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if (list_empty(&portlist))
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get_lowlevel_driver ();
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mutex_lock(®istration_lock);
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list_for_each_entry(port, &portlist, list)
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drv->attach(port);
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list_add(&drv->list, &drivers);
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mutex_unlock(®istration_lock);
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return 0;
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}
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/**
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* parport_unregister_driver - deregister a parallel port device driver
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* @drv: structure describing the driver that was given to
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* parport_register_driver()
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*
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* This should be called by a parallel port device driver that
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* has registered itself using parport_register_driver() when it
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* is about to be unloaded.
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*
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* When it returns, the driver's attach() routine will no longer
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* be called, and for each port that attach() was called for, the
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* detach() routine will have been called.
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*
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* All the driver's attach() and detach() calls are guaranteed to have
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* finished by the time this function returns.
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**/
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void parport_unregister_driver (struct parport_driver *drv)
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{
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struct parport *port;
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mutex_lock(®istration_lock);
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list_del_init(&drv->list);
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list_for_each_entry(port, &portlist, list)
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drv->detach(port);
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mutex_unlock(®istration_lock);
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}
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static void free_port (struct parport *port)
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{
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int d;
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spin_lock(&full_list_lock);
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list_del(&port->full_list);
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spin_unlock(&full_list_lock);
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for (d = 0; d < 5; d++) {
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kfree(port->probe_info[d].class_name);
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kfree(port->probe_info[d].mfr);
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kfree(port->probe_info[d].model);
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kfree(port->probe_info[d].cmdset);
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kfree(port->probe_info[d].description);
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}
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kfree(port->name);
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kfree(port);
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}
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/**
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* parport_get_port - increment a port's reference count
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* @port: the port
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*
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* This ensures that a struct parport pointer remains valid
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* until the matching parport_put_port() call.
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**/
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struct parport *parport_get_port (struct parport *port)
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{
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atomic_inc (&port->ref_count);
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return port;
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}
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/**
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* parport_put_port - decrement a port's reference count
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* @port: the port
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*
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* This should be called once for each call to parport_get_port(),
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* once the port is no longer needed.
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**/
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void parport_put_port (struct parport *port)
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{
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if (atomic_dec_and_test (&port->ref_count))
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/* Can destroy it now. */
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free_port (port);
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return;
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}
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/**
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* parport_register_port - register a parallel port
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* @base: base I/O address
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* @irq: IRQ line
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* @dma: DMA channel
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* @ops: pointer to the port driver's port operations structure
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*
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* When a parallel port (lowlevel) driver finds a port that
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* should be made available to parallel port device drivers, it
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* should call parport_register_port(). The @base, @irq, and
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* @dma parameters are for the convenience of port drivers, and
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* for ports where they aren't meaningful needn't be set to
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* anything special. They can be altered afterwards by adjusting
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* the relevant members of the parport structure that is returned
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* and represents the port. They should not be tampered with
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* after calling parport_announce_port, however.
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*
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* If there are parallel port device drivers in the system that
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* have registered themselves using parport_register_driver(),
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* they are not told about the port at this time; that is done by
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* parport_announce_port().
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*
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* The @ops structure is allocated by the caller, and must not be
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* deallocated before calling parport_remove_port().
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*
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* If there is no memory to allocate a new parport structure,
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* this function will return %NULL.
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**/
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struct parport *parport_register_port(unsigned long base, int irq, int dma,
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struct parport_operations *ops)
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{
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struct list_head *l;
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struct parport *tmp;
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int num;
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int device;
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char *name;
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tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
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if (!tmp) {
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printk(KERN_WARNING "parport: memory squeeze\n");
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return NULL;
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}
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/* Init our structure */
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tmp->base = base;
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tmp->irq = irq;
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tmp->dma = dma;
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tmp->muxport = tmp->daisy = tmp->muxsel = -1;
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tmp->modes = 0;
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INIT_LIST_HEAD(&tmp->list);
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tmp->devices = tmp->cad = NULL;
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tmp->flags = 0;
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tmp->ops = ops;
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tmp->physport = tmp;
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memset (tmp->probe_info, 0, 5 * sizeof (struct parport_device_info));
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rwlock_init(&tmp->cad_lock);
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spin_lock_init(&tmp->waitlist_lock);
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spin_lock_init(&tmp->pardevice_lock);
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tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
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tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
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sema_init(&tmp->ieee1284.irq, 0);
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tmp->spintime = parport_default_spintime;
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atomic_set (&tmp->ref_count, 1);
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INIT_LIST_HEAD(&tmp->full_list);
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name = kmalloc(15, GFP_KERNEL);
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if (!name) {
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printk(KERN_ERR "parport: memory squeeze\n");
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kfree(tmp);
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return NULL;
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}
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/* Search for the lowest free parport number. */
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spin_lock(&full_list_lock);
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for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
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struct parport *p = list_entry(l, struct parport, full_list);
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if (p->number != num)
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break;
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}
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tmp->portnum = tmp->number = num;
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list_add_tail(&tmp->full_list, l);
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spin_unlock(&full_list_lock);
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/*
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* Now that the portnum is known finish doing the Init.
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*/
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sprintf(name, "parport%d", tmp->portnum = tmp->number);
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tmp->name = name;
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for (device = 0; device < 5; device++)
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/* assume the worst */
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tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
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tmp->waithead = tmp->waittail = NULL;
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return tmp;
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}
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/**
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* parport_announce_port - tell device drivers about a parallel port
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* @port: parallel port to announce
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*
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* After a port driver has registered a parallel port with
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* parport_register_port, and performed any necessary
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* initialisation or adjustments, it should call
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* parport_announce_port() in order to notify all device drivers
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* that have called parport_register_driver(). Their attach()
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* functions will be called, with @port as the parameter.
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**/
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void parport_announce_port (struct parport *port)
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{
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int i;
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#ifdef CONFIG_PARPORT_1284
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/* Analyse the IEEE1284.3 topology of the port. */
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parport_daisy_init(port);
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#endif
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if (!port->dev)
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printk(KERN_WARNING "%s: fix this legacy "
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"no-device port driver!\n",
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port->name);
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parport_proc_register(port);
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mutex_lock(®istration_lock);
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spin_lock_irq(&parportlist_lock);
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list_add_tail(&port->list, &portlist);
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for (i = 1; i < 3; i++) {
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struct parport *slave = port->slaves[i-1];
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if (slave)
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list_add_tail(&slave->list, &portlist);
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}
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spin_unlock_irq(&parportlist_lock);
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/* Let drivers know that new port(s) has arrived. */
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attach_driver_chain (port);
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for (i = 1; i < 3; i++) {
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struct parport *slave = port->slaves[i-1];
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if (slave)
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attach_driver_chain(slave);
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}
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mutex_unlock(®istration_lock);
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}
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/**
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* parport_remove_port - deregister a parallel port
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* @port: parallel port to deregister
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*
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* When a parallel port driver is forcibly unloaded, or a
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* parallel port becomes inaccessible, the port driver must call
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* this function in order to deal with device drivers that still
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* want to use it.
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*
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* The parport structure associated with the port has its
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* operations structure replaced with one containing 'null'
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* operations that return errors or just don't do anything.
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*
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* Any drivers that have registered themselves using
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* parport_register_driver() are notified that the port is no
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* longer accessible by having their detach() routines called
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* with @port as the parameter.
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**/
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void parport_remove_port(struct parport *port)
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{
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int i;
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mutex_lock(®istration_lock);
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/* Spread the word. */
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detach_driver_chain (port);
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#ifdef CONFIG_PARPORT_1284
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/* Forget the IEEE1284.3 topology of the port. */
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parport_daisy_fini(port);
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for (i = 1; i < 3; i++) {
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struct parport *slave = port->slaves[i-1];
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if (!slave)
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continue;
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detach_driver_chain(slave);
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parport_daisy_fini(slave);
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}
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#endif
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port->ops = &dead_ops;
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spin_lock(&parportlist_lock);
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list_del_init(&port->list);
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for (i = 1; i < 3; i++) {
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struct parport *slave = port->slaves[i-1];
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if (slave)
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list_del_init(&slave->list);
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}
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spin_unlock(&parportlist_lock);
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mutex_unlock(®istration_lock);
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parport_proc_unregister(port);
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for (i = 1; i < 3; i++) {
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struct parport *slave = port->slaves[i-1];
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if (slave)
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parport_put_port(slave);
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}
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}
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/**
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* parport_register_device - register a device on a parallel port
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* @port: port to which the device is attached
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* @name: a name to refer to the device
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* @pf: preemption callback
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* @kf: kick callback (wake-up)
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* @irq_func: interrupt handler
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* @flags: registration flags
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* @handle: data for callback functions
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*
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* This function, called by parallel port device drivers,
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* declares that a device is connected to a port, and tells the
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* system all it needs to know.
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*
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* The @name is allocated by the caller and must not be
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* deallocated until the caller calls @parport_unregister_device
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* for that device.
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*
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* The preemption callback function, @pf, is called when this
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* device driver has claimed access to the port but another
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* device driver wants to use it. It is given @handle as its
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* parameter, and should return zero if it is willing for the
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* system to release the port to another driver on its behalf.
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* If it wants to keep control of the port it should return
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* non-zero, and no action will be taken. It is good manners for
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* the driver to try to release the port at the earliest
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* opportunity after its preemption callback rejects a preemption
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* attempt. Note that if a preemption callback is happy for
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* preemption to go ahead, there is no need to release the port;
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* it is done automatically. This function may not block, as it
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* may be called from interrupt context. If the device driver
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* does not support preemption, @pf can be %NULL.
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*
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* The wake-up ("kick") callback function, @kf, is called when
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* the port is available to be claimed for exclusive access; that
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* is, parport_claim() is guaranteed to succeed when called from
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* inside the wake-up callback function. If the driver wants to
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* claim the port it should do so; otherwise, it need not take
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* any action. This function may not block, as it may be called
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* from interrupt context. If the device driver does not want to
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* be explicitly invited to claim the port in this way, @kf can
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* be %NULL.
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*
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|
* 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) {
|
|
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);
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
|
|
port = dev->port->physport;
|
|
|
|
if (port->proc_device == dev) {
|
|
port->proc_device = NULL;
|
|
clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
|
|
parport_device_proc_unregister(dev);
|
|
}
|
|
|
|
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_irq(&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_irq(&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);
|
|
}
|
|
}
|
|
|
|
irqreturn_t parport_irq_handler(int irq, void *dev_id)
|
|
{
|
|
struct parport *port = dev_id;
|
|
|
|
parport_generic_irq(port);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
/* 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);
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EXPORT_SYMBOL(parport_get_port);
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EXPORT_SYMBOL(parport_put_port);
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EXPORT_SYMBOL(parport_find_number);
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EXPORT_SYMBOL(parport_find_base);
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EXPORT_SYMBOL(parport_irq_handler);
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MODULE_LICENSE("GPL");
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