/* * Parallel-port resource manager code. * * Authors: David Campbell <[email protected]> * Tim Waugh <[email protected]> * Jose Renau <[email protected]> * Philip Blundell <[email protected]> * Andrea Arcangeli * * based on work by Grant Guenther <[email protected]> * 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/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/signal.h> #include <linux/kmod.h> #include <linux/device.h> #include <linux/spinlock.h> #include <linux/mutex.h> #include <asm/irq.h> #undef PARPORT_PARANOID #define PARPORT_DEFAULT_TIMESLICE … unsigned long parport_default_timeslice = …; int parport_default_spintime = …; 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 DEFINE_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) { … } static unsigned char dead_frob_lines(struct parport *p, unsigned char b, unsigned char c) { … } 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) { … } static size_t dead_read(struct parport *p, void *b, size_t l, int f) { … } static struct parport_operations dead_ops = …; static struct device_type parport_device_type = …; static int is_parport(struct device *dev) { … } static int parport_probe(struct device *dev) { … } static const struct bus_type parport_bus_type = …; int parport_bus_init(void) { … } void parport_bus_exit(void) { … } /* * iterates through all the drivers registered with the bus and sends the port * details to the match_port callback of the driver, so that the driver can * know about the new port that just registered with the bus and decide if it * wants to use this new port. */ static int driver_check(struct device_driver *dev_drv, void *_port) { … } /* Call attach(port) for each registered driver. */ static void attach_driver_chain(struct parport *port) { … } static int driver_detach(struct device_driver *_drv, void *_port) { … } /* Call detach(port) for each registered driver. */ static void detach_driver_chain(struct parport *port) { … } /* Ask kmod for some lowlevel drivers. */ static void get_lowlevel_driver(void) { … } /* * iterates through all the devices connected to the bus and sends the device * details to the match_port callback of the driver, so that the driver can * know what are all the ports that are connected to the bus and choose the * port to which it wants to register its device. */ static int port_check(struct device *dev, void *dev_drv) { … } /* * Iterates through all the devices connected to the bus and return 1 * if the device is a parallel port. */ static int port_detect(struct device *dev, void *dev_drv) { … } /** * __parport_register_driver - register a parallel port device driver * @drv: structure describing the driver * @owner: owner module of drv * @mod_name: module name string * * 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. * * If devmodel is true then the new device model is used * for registration. * * The @drv structure is allocated by the caller and must not be * deallocated until after calling parport_unregister_driver(). * * If using the non device model: * 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. The non device model will always succeeds. * but the new device model can fail and will return the error code. **/ int __parport_register_driver(struct parport_driver *drv, struct module *owner, const char *mod_name) { … } EXPORT_SYMBOL(…); static int port_detach(struct device *dev, void *_drv) { … } /** * 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) { … } EXPORT_SYMBOL(…); static void free_port(struct device *dev) { … } /** * parport_get_port - increment a port's reference count * @port: the port * * This ensures that a struct parport pointer remains valid * until the matching parport_put_port() call. **/ struct parport *parport_get_port(struct parport *port) { … } EXPORT_SYMBOL(…); void parport_del_port(struct parport *port) { … } EXPORT_SYMBOL(…); /** * 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. When the reference count reaches * zero (port is no longer used), free_port is called. **/ void parport_put_port(struct parport *port) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); static void free_pardevice(struct device *dev) { … } /** * parport_register_dev_model - register a device on a parallel port * @port: port to which the device is attached * @name: a name to refer to the device * @par_dev_cb: struct containing callbacks * @id: device number to be given to the device * * 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 struct pardev_cb contains pointer to callbacks. preemption * callback function, @preempt, is called when this device driver * has claimed access to the port but another device driver wants * to use it. It is given, @private, 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, @preempt can be %NULL. * * The wake-up ("kick") callback function, @wakeup, 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, @wakeup 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_dev_model(struct parport *port, const char *name, const struct pardev_cb *par_dev_cb, int id) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } EXPORT_SYMBOL(…); irqreturn_t parport_irq_handler(int irq, void *dev_id) { … } EXPORT_SYMBOL(…); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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