linux/drivers/parport/share.c
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   1/*
   2 * Parallel-port resource manager code.
   3 *
   4 * Authors: David Campbell <campbell@tirian.che.curtin.edu.au>
   5 *          Tim Waugh <tim@cyberelk.demon.co.uk>
   6 *          Jose Renau <renau@acm.org>
   7 *          Philip Blundell <philb@gnu.org>
   8 *          Andrea Arcangeli
   9 *
  10 * based on work by Grant Guenther <grant@torque.net>
  11 *          and Philip Blundell
  12 *
  13 * Any part of this program may be used in documents licensed under
  14 * the GNU Free Documentation License, Version 1.1 or any later version
  15 * published by the Free Software Foundation.
  16 */
  17
  18#undef PARPORT_DEBUG_SHARING            /* undef for production */
  19
  20#include <linux/module.h>
  21#include <linux/string.h>
  22#include <linux/threads.h>
  23#include <linux/parport.h>
  24#include <linux/delay.h>
  25#include <linux/errno.h>
  26#include <linux/interrupt.h>
  27#include <linux/ioport.h>
  28#include <linux/kernel.h>
  29#include <linux/slab.h>
  30#include <linux/sched.h>
  31#include <linux/kmod.h>
  32#include <linux/device.h>
  33
  34#include <linux/spinlock.h>
  35#include <linux/mutex.h>
  36#include <asm/irq.h>
  37
  38#undef PARPORT_PARANOID
  39
  40#define PARPORT_DEFAULT_TIMESLICE       (HZ/5)
  41
  42unsigned long parport_default_timeslice = PARPORT_DEFAULT_TIMESLICE;
  43int parport_default_spintime =  DEFAULT_SPIN_TIME;
  44
  45static LIST_HEAD(portlist);
  46static DEFINE_SPINLOCK(parportlist_lock);
  47
  48/* list of all allocated ports, sorted by ->number */
  49static LIST_HEAD(all_ports);
  50static DEFINE_SPINLOCK(full_list_lock);
  51
  52static LIST_HEAD(drivers);
  53
  54static DEFINE_MUTEX(registration_lock);
  55
  56/* What you can do to a port that's gone away.. */
  57static void dead_write_lines(struct parport *p, unsigned char b){}
  58static unsigned char dead_read_lines(struct parport *p) { return 0; }
  59static unsigned char dead_frob_lines(struct parport *p, unsigned char b,
  60                             unsigned char c) { return 0; }
  61static void dead_onearg(struct parport *p){}
  62static void dead_initstate(struct pardevice *d, struct parport_state *s) { }
  63static void dead_state(struct parport *p, struct parport_state *s) { }
  64static size_t dead_write(struct parport *p, const void *b, size_t l, int f)
  65{ return 0; }
  66static size_t dead_read(struct parport *p, void *b, size_t l, int f)
  67{ return 0; }
  68static struct parport_operations dead_ops = {
  69        .write_data     = dead_write_lines,     /* data */
  70        .read_data      = dead_read_lines,
  71
  72        .write_control  = dead_write_lines,     /* control */
  73        .read_control   = dead_read_lines,
  74        .frob_control   = dead_frob_lines,
  75
  76        .read_status    = dead_read_lines,      /* status */
  77
  78        .enable_irq     = dead_onearg,          /* enable_irq */
  79        .disable_irq    = dead_onearg,          /* disable_irq */
  80
  81        .data_forward   = dead_onearg,          /* data_forward */
  82        .data_reverse   = dead_onearg,          /* data_reverse */
  83
  84        .init_state     = dead_initstate,       /* init_state */
  85        .save_state     = dead_state,
  86        .restore_state  = dead_state,
  87
  88        .epp_write_data = dead_write,           /* epp */
  89        .epp_read_data  = dead_read,
  90        .epp_write_addr = dead_write,
  91        .epp_read_addr  = dead_read,
  92
  93        .ecp_write_data = dead_write,           /* ecp */
  94        .ecp_read_data  = dead_read,
  95        .ecp_write_addr = dead_write,
  96
  97        .compat_write_data      = dead_write,   /* compat */
  98        .nibble_read_data       = dead_read,    /* nibble */
  99        .byte_read_data         = dead_read,    /* byte */
 100
 101        .owner          = NULL,
 102};
 103
 104static struct device_type parport_device_type = {
 105        .name = "parport",
 106};
 107
 108static int is_parport(struct device *dev)
 109{
 110        return dev->type == &parport_device_type;
 111}
 112
 113static int parport_probe(struct device *dev)
 114{
 115        struct parport_driver *drv;
 116
 117        if (is_parport(dev))
 118                return -ENODEV;
 119
 120        drv = to_parport_driver(dev->driver);
 121        if (!drv->probe) {
 122                /* if driver has not defined a custom probe */
 123                struct pardevice *par_dev = to_pardevice(dev);
 124
 125                if (strcmp(par_dev->name, drv->name))
 126                        return -ENODEV;
 127                return 0;
 128        }
 129        /* if driver defined its own probe */
 130        return drv->probe(to_pardevice(dev));
 131}
 132
 133static struct bus_type parport_bus_type = {
 134        .name = "parport",
 135        .probe = parport_probe,
 136};
 137
 138int parport_bus_init(void)
 139{
 140        return bus_register(&parport_bus_type);
 141}
 142
 143void parport_bus_exit(void)
 144{
 145        bus_unregister(&parport_bus_type);
 146}
 147
 148/*
 149 * iterates through all the drivers registered with the bus and sends the port
 150 * details to the match_port callback of the driver, so that the driver can
 151 * know about the new port that just registered with the bus and decide if it
 152 * wants to use this new port.
 153 */
 154static int driver_check(struct device_driver *dev_drv, void *_port)
 155{
 156        struct parport *port = _port;
 157        struct parport_driver *drv = to_parport_driver(dev_drv);
 158
 159        if (drv->match_port)
 160                drv->match_port(port);
 161        return 0;
 162}
 163
 164/* Call attach(port) for each registered driver. */
 165static void attach_driver_chain(struct parport *port)
 166{
 167        /* caller has exclusive registration_lock */
 168        struct parport_driver *drv;
 169
 170        list_for_each_entry(drv, &drivers, list)
 171                drv->attach(port);
 172
 173        /*
 174         * call the driver_check function of the drivers registered in
 175         * new device model
 176         */
 177
 178        bus_for_each_drv(&parport_bus_type, NULL, port, driver_check);
 179}
 180
 181static int driver_detach(struct device_driver *_drv, void *_port)
 182{
 183        struct parport *port = _port;
 184        struct parport_driver *drv = to_parport_driver(_drv);
 185
 186        if (drv->detach)
 187                drv->detach(port);
 188        return 0;
 189}
 190
 191/* Call detach(port) for each registered driver. */
 192static void detach_driver_chain(struct parport *port)
 193{
 194        struct parport_driver *drv;
 195        /* caller has exclusive registration_lock */
 196        list_for_each_entry(drv, &drivers, list)
 197                drv->detach(port);
 198
 199        /*
 200         * call the detach function of the drivers registered in
 201         * new device model
 202         */
 203
 204        bus_for_each_drv(&parport_bus_type, NULL, port, driver_detach);
 205}
 206
 207/* Ask kmod for some lowlevel drivers. */
 208static void get_lowlevel_driver(void)
 209{
 210        /*
 211         * There is no actual module called this: you should set
 212         * up an alias for modutils.
 213         */
 214        request_module("parport_lowlevel");
 215}
 216
 217/*
 218 * iterates through all the devices connected to the bus and sends the device
 219 * details to the match_port callback of the driver, so that the driver can
 220 * know what are all the ports that are connected to the bus and choose the
 221 * port to which it wants to register its device.
 222 */
 223static int port_check(struct device *dev, void *dev_drv)
 224{
 225        struct parport_driver *drv = dev_drv;
 226
 227        /* only send ports, do not send other devices connected to bus */
 228        if (is_parport(dev))
 229                drv->match_port(to_parport_dev(dev));
 230        return 0;
 231}
 232
 233/**
 234 *      parport_register_driver - register a parallel port device driver
 235 *      @drv: structure describing the driver
 236 *      @owner: owner module of drv
 237 *      @mod_name: module name string
 238 *
 239 *      This can be called by a parallel port device driver in order
 240 *      to receive notifications about ports being found in the
 241 *      system, as well as ports no longer available.
 242 *
 243 *      If devmodel is true then the new device model is used
 244 *      for registration.
 245 *
 246 *      The @drv structure is allocated by the caller and must not be
 247 *      deallocated until after calling parport_unregister_driver().
 248 *
 249 *      If using the non device model:
 250 *      The driver's attach() function may block.  The port that
 251 *      attach() is given will be valid for the duration of the
 252 *      callback, but if the driver wants to take a copy of the
 253 *      pointer it must call parport_get_port() to do so.  Calling
 254 *      parport_register_device() on that port will do this for you.
 255 *
 256 *      The driver's detach() function may block.  The port that
 257 *      detach() is given will be valid for the duration of the
 258 *      callback, but if the driver wants to take a copy of the
 259 *      pointer it must call parport_get_port() to do so.
 260 *
 261 *
 262 *      Returns 0 on success. The non device model will always succeeds.
 263 *      but the new device model can fail and will return the error code.
 264 **/
 265
 266int __parport_register_driver(struct parport_driver *drv, struct module *owner,
 267                              const char *mod_name)
 268{
 269        if (list_empty(&portlist))
 270                get_lowlevel_driver();
 271
 272        if (drv->devmodel) {
 273                /* using device model */
 274                int ret;
 275
 276                /* initialize common driver fields */
 277                drv->driver.name = drv->name;
 278                drv->driver.bus = &parport_bus_type;
 279                drv->driver.owner = owner;
 280                drv->driver.mod_name = mod_name;
 281                ret = driver_register(&drv->driver);
 282                if (ret)
 283                        return ret;
 284
 285                mutex_lock(&registration_lock);
 286                if (drv->match_port)
 287                        bus_for_each_dev(&parport_bus_type, NULL, drv,
 288                                         port_check);
 289                mutex_unlock(&registration_lock);
 290        } else {
 291                struct parport *port;
 292
 293                drv->devmodel = false;
 294
 295                mutex_lock(&registration_lock);
 296                list_for_each_entry(port, &portlist, list)
 297                        drv->attach(port);
 298                list_add(&drv->list, &drivers);
 299                mutex_unlock(&registration_lock);
 300        }
 301
 302        return 0;
 303}
 304EXPORT_SYMBOL(__parport_register_driver);
 305
 306static int port_detach(struct device *dev, void *_drv)
 307{
 308        struct parport_driver *drv = _drv;
 309
 310        if (is_parport(dev) && drv->detach)
 311                drv->detach(to_parport_dev(dev));
 312
 313        return 0;
 314}
 315
 316/**
 317 *      parport_unregister_driver - deregister a parallel port device driver
 318 *      @drv: structure describing the driver that was given to
 319 *            parport_register_driver()
 320 *
 321 *      This should be called by a parallel port device driver that
 322 *      has registered itself using parport_register_driver() when it
 323 *      is about to be unloaded.
 324 *
 325 *      When it returns, the driver's attach() routine will no longer
 326 *      be called, and for each port that attach() was called for, the
 327 *      detach() routine will have been called.
 328 *
 329 *      All the driver's attach() and detach() calls are guaranteed to have
 330 *      finished by the time this function returns.
 331 **/
 332
 333void parport_unregister_driver(struct parport_driver *drv)
 334{
 335        struct parport *port;
 336
 337        mutex_lock(&registration_lock);
 338        if (drv->devmodel) {
 339                bus_for_each_dev(&parport_bus_type, NULL, drv, port_detach);
 340                driver_unregister(&drv->driver);
 341        } else {
 342                list_del_init(&drv->list);
 343                list_for_each_entry(port, &portlist, list)
 344                        drv->detach(port);
 345        }
 346        mutex_unlock(&registration_lock);
 347}
 348EXPORT_SYMBOL(parport_unregister_driver);
 349
 350static void free_port(struct device *dev)
 351{
 352        int d;
 353        struct parport *port = to_parport_dev(dev);
 354
 355        spin_lock(&full_list_lock);
 356        list_del(&port->full_list);
 357        spin_unlock(&full_list_lock);
 358        for (d = 0; d < 5; d++) {
 359                kfree(port->probe_info[d].class_name);
 360                kfree(port->probe_info[d].mfr);
 361                kfree(port->probe_info[d].model);
 362                kfree(port->probe_info[d].cmdset);
 363                kfree(port->probe_info[d].description);
 364        }
 365
 366        kfree(port->name);
 367        kfree(port);
 368}
 369
 370/**
 371 *      parport_get_port - increment a port's reference count
 372 *      @port: the port
 373 *
 374 *      This ensures that a struct parport pointer remains valid
 375 *      until the matching parport_put_port() call.
 376 **/
 377
 378struct parport *parport_get_port(struct parport *port)
 379{
 380        struct device *dev = get_device(&port->bus_dev);
 381
 382        return to_parport_dev(dev);
 383}
 384EXPORT_SYMBOL(parport_get_port);
 385
 386void parport_del_port(struct parport *port)
 387{
 388        device_unregister(&port->bus_dev);
 389}
 390EXPORT_SYMBOL(parport_del_port);
 391
 392/**
 393 *      parport_put_port - decrement a port's reference count
 394 *      @port: the port
 395 *
 396 *      This should be called once for each call to parport_get_port(),
 397 *      once the port is no longer needed. When the reference count reaches
 398 *      zero (port is no longer used), free_port is called.
 399 **/
 400
 401void parport_put_port(struct parport *port)
 402{
 403        put_device(&port->bus_dev);
 404}
 405EXPORT_SYMBOL(parport_put_port);
 406
 407/**
 408 *      parport_register_port - register a parallel port
 409 *      @base: base I/O address
 410 *      @irq: IRQ line
 411 *      @dma: DMA channel
 412 *      @ops: pointer to the port driver's port operations structure
 413 *
 414 *      When a parallel port (lowlevel) driver finds a port that
 415 *      should be made available to parallel port device drivers, it
 416 *      should call parport_register_port().  The @base, @irq, and
 417 *      @dma parameters are for the convenience of port drivers, and
 418 *      for ports where they aren't meaningful needn't be set to
 419 *      anything special.  They can be altered afterwards by adjusting
 420 *      the relevant members of the parport structure that is returned
 421 *      and represents the port.  They should not be tampered with
 422 *      after calling parport_announce_port, however.
 423 *
 424 *      If there are parallel port device drivers in the system that
 425 *      have registered themselves using parport_register_driver(),
 426 *      they are not told about the port at this time; that is done by
 427 *      parport_announce_port().
 428 *
 429 *      The @ops structure is allocated by the caller, and must not be
 430 *      deallocated before calling parport_remove_port().
 431 *
 432 *      If there is no memory to allocate a new parport structure,
 433 *      this function will return %NULL.
 434 **/
 435
 436struct parport *parport_register_port(unsigned long base, int irq, int dma,
 437                                      struct parport_operations *ops)
 438{
 439        struct list_head *l;
 440        struct parport *tmp;
 441        int num;
 442        int device;
 443        char *name;
 444        int ret;
 445
 446        tmp = kzalloc(sizeof(struct parport), GFP_KERNEL);
 447        if (!tmp)
 448                return NULL;
 449
 450        /* Init our structure */
 451        tmp->base = base;
 452        tmp->irq = irq;
 453        tmp->dma = dma;
 454        tmp->muxport = tmp->daisy = tmp->muxsel = -1;
 455        tmp->modes = 0;
 456        INIT_LIST_HEAD(&tmp->list);
 457        tmp->devices = tmp->cad = NULL;
 458        tmp->flags = 0;
 459        tmp->ops = ops;
 460        tmp->physport = tmp;
 461        memset(tmp->probe_info, 0, 5 * sizeof(struct parport_device_info));
 462        rwlock_init(&tmp->cad_lock);
 463        spin_lock_init(&tmp->waitlist_lock);
 464        spin_lock_init(&tmp->pardevice_lock);
 465        tmp->ieee1284.mode = IEEE1284_MODE_COMPAT;
 466        tmp->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 467        sema_init(&tmp->ieee1284.irq, 0);
 468        tmp->spintime = parport_default_spintime;
 469        atomic_set(&tmp->ref_count, 1);
 470        INIT_LIST_HEAD(&tmp->full_list);
 471
 472        name = kmalloc(15, GFP_KERNEL);
 473        if (!name) {
 474                kfree(tmp);
 475                return NULL;
 476        }
 477        /* Search for the lowest free parport number. */
 478
 479        spin_lock(&full_list_lock);
 480        for (l = all_ports.next, num = 0; l != &all_ports; l = l->next, num++) {
 481                struct parport *p = list_entry(l, struct parport, full_list);
 482                if (p->number != num)
 483                        break;
 484        }
 485        tmp->portnum = tmp->number = num;
 486        list_add_tail(&tmp->full_list, l);
 487        spin_unlock(&full_list_lock);
 488
 489        /*
 490         * Now that the portnum is known finish doing the Init.
 491         */
 492        sprintf(name, "parport%d", tmp->portnum = tmp->number);
 493        tmp->name = name;
 494        tmp->bus_dev.bus = &parport_bus_type;
 495        tmp->bus_dev.release = free_port;
 496        dev_set_name(&tmp->bus_dev, name);
 497        tmp->bus_dev.type = &parport_device_type;
 498
 499        for (device = 0; device < 5; device++)
 500                /* assume the worst */
 501                tmp->probe_info[device].class = PARPORT_CLASS_LEGACY;
 502
 503        tmp->waithead = tmp->waittail = NULL;
 504
 505        ret = device_register(&tmp->bus_dev);
 506        if (ret) {
 507                put_device(&tmp->bus_dev);
 508                return NULL;
 509        }
 510
 511        return tmp;
 512}
 513EXPORT_SYMBOL(parport_register_port);
 514
 515/**
 516 *      parport_announce_port - tell device drivers about a parallel port
 517 *      @port: parallel port to announce
 518 *
 519 *      After a port driver has registered a parallel port with
 520 *      parport_register_port, and performed any necessary
 521 *      initialisation or adjustments, it should call
 522 *      parport_announce_port() in order to notify all device drivers
 523 *      that have called parport_register_driver().  Their attach()
 524 *      functions will be called, with @port as the parameter.
 525 **/
 526
 527void parport_announce_port(struct parport *port)
 528{
 529        int i;
 530
 531#ifdef CONFIG_PARPORT_1284
 532        /* Analyse the IEEE1284.3 topology of the port. */
 533        parport_daisy_init(port);
 534#endif
 535
 536        if (!port->dev)
 537                printk(KERN_WARNING "%s: fix this legacy no-device port driver!\n",
 538                       port->name);
 539
 540        parport_proc_register(port);
 541        mutex_lock(&registration_lock);
 542        spin_lock_irq(&parportlist_lock);
 543        list_add_tail(&port->list, &portlist);
 544        for (i = 1; i < 3; i++) {
 545                struct parport *slave = port->slaves[i-1];
 546                if (slave)
 547                        list_add_tail(&slave->list, &portlist);
 548        }
 549        spin_unlock_irq(&parportlist_lock);
 550
 551        /* Let drivers know that new port(s) has arrived. */
 552        attach_driver_chain(port);
 553        for (i = 1; i < 3; i++) {
 554                struct parport *slave = port->slaves[i-1];
 555                if (slave)
 556                        attach_driver_chain(slave);
 557        }
 558        mutex_unlock(&registration_lock);
 559}
 560EXPORT_SYMBOL(parport_announce_port);
 561
 562/**
 563 *      parport_remove_port - deregister a parallel port
 564 *      @port: parallel port to deregister
 565 *
 566 *      When a parallel port driver is forcibly unloaded, or a
 567 *      parallel port becomes inaccessible, the port driver must call
 568 *      this function in order to deal with device drivers that still
 569 *      want to use it.
 570 *
 571 *      The parport structure associated with the port has its
 572 *      operations structure replaced with one containing 'null'
 573 *      operations that return errors or just don't do anything.
 574 *
 575 *      Any drivers that have registered themselves using
 576 *      parport_register_driver() are notified that the port is no
 577 *      longer accessible by having their detach() routines called
 578 *      with @port as the parameter.
 579 **/
 580
 581void parport_remove_port(struct parport *port)
 582{
 583        int i;
 584
 585        mutex_lock(&registration_lock);
 586
 587        /* Spread the word. */
 588        detach_driver_chain(port);
 589
 590#ifdef CONFIG_PARPORT_1284
 591        /* Forget the IEEE1284.3 topology of the port. */
 592        parport_daisy_fini(port);
 593        for (i = 1; i < 3; i++) {
 594                struct parport *slave = port->slaves[i-1];
 595                if (!slave)
 596                        continue;
 597                detach_driver_chain(slave);
 598                parport_daisy_fini(slave);
 599        }
 600#endif
 601
 602        port->ops = &dead_ops;
 603        spin_lock(&parportlist_lock);
 604        list_del_init(&port->list);
 605        for (i = 1; i < 3; i++) {
 606                struct parport *slave = port->slaves[i-1];
 607                if (slave)
 608                        list_del_init(&slave->list);
 609        }
 610        spin_unlock(&parportlist_lock);
 611
 612        mutex_unlock(&registration_lock);
 613
 614        parport_proc_unregister(port);
 615
 616        for (i = 1; i < 3; i++) {
 617                struct parport *slave = port->slaves[i-1];
 618                if (slave)
 619                        parport_put_port(slave);
 620        }
 621}
 622EXPORT_SYMBOL(parport_remove_port);
 623
 624/**
 625 *      parport_register_device - register a device on a parallel port
 626 *      @port: port to which the device is attached
 627 *      @name: a name to refer to the device
 628 *      @pf: preemption callback
 629 *      @kf: kick callback (wake-up)
 630 *      @irq_func: interrupt handler
 631 *      @flags: registration flags
 632 *      @handle: data for callback functions
 633 *
 634 *      This function, called by parallel port device drivers,
 635 *      declares that a device is connected to a port, and tells the
 636 *      system all it needs to know.
 637 *
 638 *      The @name is allocated by the caller and must not be
 639 *      deallocated until the caller calls @parport_unregister_device
 640 *      for that device.
 641 *
 642 *      The preemption callback function, @pf, is called when this
 643 *      device driver has claimed access to the port but another
 644 *      device driver wants to use it.  It is given @handle as its
 645 *      parameter, and should return zero if it is willing for the
 646 *      system to release the port to another driver on its behalf.
 647 *      If it wants to keep control of the port it should return
 648 *      non-zero, and no action will be taken.  It is good manners for
 649 *      the driver to try to release the port at the earliest
 650 *      opportunity after its preemption callback rejects a preemption
 651 *      attempt.  Note that if a preemption callback is happy for
 652 *      preemption to go ahead, there is no need to release the port;
 653 *      it is done automatically.  This function may not block, as it
 654 *      may be called from interrupt context.  If the device driver
 655 *      does not support preemption, @pf can be %NULL.
 656 *
 657 *      The wake-up ("kick") callback function, @kf, is called when
 658 *      the port is available to be claimed for exclusive access; that
 659 *      is, parport_claim() is guaranteed to succeed when called from
 660 *      inside the wake-up callback function.  If the driver wants to
 661 *      claim the port it should do so; otherwise, it need not take
 662 *      any action.  This function may not block, as it may be called
 663 *      from interrupt context.  If the device driver does not want to
 664 *      be explicitly invited to claim the port in this way, @kf can
 665 *      be %NULL.
 666 *
 667 *      The interrupt handler, @irq_func, is called when an interrupt
 668 *      arrives from the parallel port.  Note that if a device driver
 669 *      wants to use interrupts it should use parport_enable_irq(),
 670 *      and can also check the irq member of the parport structure
 671 *      representing the port.
 672 *
 673 *      The parallel port (lowlevel) driver is the one that has called
 674 *      request_irq() and whose interrupt handler is called first.
 675 *      This handler does whatever needs to be done to the hardware to
 676 *      acknowledge the interrupt (for PC-style ports there is nothing
 677 *      special to be done).  It then tells the IEEE 1284 code about
 678 *      the interrupt, which may involve reacting to an IEEE 1284
 679 *      event depending on the current IEEE 1284 phase.  After this,
 680 *      it calls @irq_func.  Needless to say, @irq_func will be called
 681 *      from interrupt context, and may not block.
 682 *
 683 *      The %PARPORT_DEV_EXCL flag is for preventing port sharing, and
 684 *      so should only be used when sharing the port with other device
 685 *      drivers is impossible and would lead to incorrect behaviour.
 686 *      Use it sparingly!  Normally, @flags will be zero.
 687 *
 688 *      This function returns a pointer to a structure that represents
 689 *      the device on the port, or %NULL if there is not enough memory
 690 *      to allocate space for that structure.
 691 **/
 692
 693struct pardevice *
 694parport_register_device(struct parport *port, const char *name,
 695                        int (*pf)(void *), void (*kf)(void *),
 696                        void (*irq_func)(void *),
 697                        int flags, void *handle)
 698{
 699        struct pardevice *tmp;
 700
 701        if (port->physport->flags & PARPORT_FLAG_EXCL) {
 702                /* An exclusive device is registered. */
 703                printk(KERN_DEBUG "%s: no more devices allowed\n",
 704                        port->name);
 705                return NULL;
 706        }
 707
 708        if (flags & PARPORT_DEV_LURK) {
 709                if (!pf || !kf) {
 710                        printk(KERN_INFO "%s: refused to register lurking device (%s) without callbacks\n", port->name, name);
 711                        return NULL;
 712                }
 713        }
 714
 715        if (flags & PARPORT_DEV_EXCL) {
 716                if (port->physport->devices) {
 717                        /*
 718                         * If a device is already registered and this new
 719                         * device wants exclusive access, then no need to
 720                         * continue as we can not grant exclusive access to
 721                         * this device.
 722                         */
 723                        pr_err("%s: cannot grant exclusive access for device %s\n",
 724                               port->name, name);
 725                        return NULL;
 726                }
 727        }
 728
 729        /*
 730         * We up our own module reference count, and that of the port
 731         * on which a device is to be registered, to ensure that
 732         * neither of us gets unloaded while we sleep in (e.g.)
 733         * kmalloc.
 734         */
 735        if (!try_module_get(port->ops->owner))
 736                return NULL;
 737
 738        parport_get_port(port);
 739
 740        tmp = kmalloc(sizeof(struct pardevice), GFP_KERNEL);
 741        if (!tmp)
 742                goto out;
 743
 744        tmp->state = kmalloc(sizeof(struct parport_state), GFP_KERNEL);
 745        if (!tmp->state)
 746                goto out_free_pardevice;
 747
 748        tmp->name = name;
 749        tmp->port = port;
 750        tmp->daisy = -1;
 751        tmp->preempt = pf;
 752        tmp->wakeup = kf;
 753        tmp->private = handle;
 754        tmp->flags = flags;
 755        tmp->irq_func = irq_func;
 756        tmp->waiting = 0;
 757        tmp->timeout = 5 * HZ;
 758        tmp->devmodel = false;
 759
 760        /* Chain this onto the list */
 761        tmp->prev = NULL;
 762        /*
 763         * This function must not run from an irq handler so we don' t need
 764         * to clear irq on the local CPU. -arca
 765         */
 766        spin_lock(&port->physport->pardevice_lock);
 767
 768        if (flags & PARPORT_DEV_EXCL) {
 769                if (port->physport->devices) {
 770                        spin_unlock(&port->physport->pardevice_lock);
 771                        printk(KERN_DEBUG
 772                                "%s: cannot grant exclusive access for device %s\n",
 773                                port->name, name);
 774                        goto out_free_all;
 775                }
 776                port->flags |= PARPORT_FLAG_EXCL;
 777        }
 778
 779        tmp->next = port->physport->devices;
 780        wmb(); /*
 781                * Make sure that tmp->next is written before it's
 782                * added to the list; see comments marked 'no locking
 783                * required'
 784                */
 785        if (port->physport->devices)
 786                port->physport->devices->prev = tmp;
 787        port->physport->devices = tmp;
 788        spin_unlock(&port->physport->pardevice_lock);
 789
 790        init_waitqueue_head(&tmp->wait_q);
 791        tmp->timeslice = parport_default_timeslice;
 792        tmp->waitnext = tmp->waitprev = NULL;
 793
 794        /*
 795         * This has to be run as last thing since init_state may need other
 796         * pardevice fields. -arca
 797         */
 798        port->ops->init_state(tmp, tmp->state);
 799        if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
 800                port->proc_device = tmp;
 801                parport_device_proc_register(tmp);
 802        }
 803        return tmp;
 804
 805 out_free_all:
 806        kfree(tmp->state);
 807 out_free_pardevice:
 808        kfree(tmp);
 809 out:
 810        parport_put_port(port);
 811        module_put(port->ops->owner);
 812
 813        return NULL;
 814}
 815EXPORT_SYMBOL(parport_register_device);
 816
 817static void free_pardevice(struct device *dev)
 818{
 819        struct pardevice *par_dev = to_pardevice(dev);
 820
 821        kfree(par_dev->name);
 822        kfree(par_dev);
 823}
 824
 825struct pardevice *
 826parport_register_dev_model(struct parport *port, const char *name,
 827                           const struct pardev_cb *par_dev_cb, int id)
 828{
 829        struct pardevice *par_dev;
 830        int ret;
 831        char *devname;
 832
 833        if (port->physport->flags & PARPORT_FLAG_EXCL) {
 834                /* An exclusive device is registered. */
 835                pr_err("%s: no more devices allowed\n", port->name);
 836                return NULL;
 837        }
 838
 839        if (par_dev_cb->flags & PARPORT_DEV_LURK) {
 840                if (!par_dev_cb->preempt || !par_dev_cb->wakeup) {
 841                        pr_info("%s: refused to register lurking device (%s) without callbacks\n",
 842                                port->name, name);
 843                        return NULL;
 844                }
 845        }
 846
 847        if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
 848                if (port->physport->devices) {
 849                        /*
 850                         * If a device is already registered and this new
 851                         * device wants exclusive access, then no need to
 852                         * continue as we can not grant exclusive access to
 853                         * this device.
 854                         */
 855                        pr_err("%s: cannot grant exclusive access for device %s\n",
 856                               port->name, name);
 857                        return NULL;
 858                }
 859        }
 860
 861        if (!try_module_get(port->ops->owner))
 862                return NULL;
 863
 864        parport_get_port(port);
 865
 866        par_dev = kzalloc(sizeof(*par_dev), GFP_KERNEL);
 867        if (!par_dev)
 868                goto err_put_port;
 869
 870        par_dev->state = kzalloc(sizeof(*par_dev->state), GFP_KERNEL);
 871        if (!par_dev->state)
 872                goto err_put_par_dev;
 873
 874        devname = kstrdup(name, GFP_KERNEL);
 875        if (!devname)
 876                goto err_free_par_dev;
 877
 878        par_dev->name = devname;
 879        par_dev->port = port;
 880        par_dev->daisy = -1;
 881        par_dev->preempt = par_dev_cb->preempt;
 882        par_dev->wakeup = par_dev_cb->wakeup;
 883        par_dev->private = par_dev_cb->private;
 884        par_dev->flags = par_dev_cb->flags;
 885        par_dev->irq_func = par_dev_cb->irq_func;
 886        par_dev->waiting = 0;
 887        par_dev->timeout = 5 * HZ;
 888
 889        par_dev->dev.parent = &port->bus_dev;
 890        par_dev->dev.bus = &parport_bus_type;
 891        ret = dev_set_name(&par_dev->dev, "%s.%d", devname, id);
 892        if (ret)
 893                goto err_free_devname;
 894        par_dev->dev.release = free_pardevice;
 895        par_dev->devmodel = true;
 896        ret = device_register(&par_dev->dev);
 897        if (ret) {
 898                put_device(&par_dev->dev);
 899                goto err_put_port;
 900        }
 901
 902        /* Chain this onto the list */
 903        par_dev->prev = NULL;
 904        /*
 905         * This function must not run from an irq handler so we don' t need
 906         * to clear irq on the local CPU. -arca
 907         */
 908        spin_lock(&port->physport->pardevice_lock);
 909
 910        if (par_dev_cb->flags & PARPORT_DEV_EXCL) {
 911                if (port->physport->devices) {
 912                        spin_unlock(&port->physport->pardevice_lock);
 913                        pr_debug("%s: cannot grant exclusive access for device %s\n",
 914                                 port->name, name);
 915                        device_unregister(&par_dev->dev);
 916                        goto err_put_port;
 917                }
 918                port->flags |= PARPORT_FLAG_EXCL;
 919        }
 920
 921        par_dev->next = port->physport->devices;
 922        wmb();  /*
 923                 * Make sure that tmp->next is written before it's
 924                 * added to the list; see comments marked 'no locking
 925                 * required'
 926                 */
 927        if (port->physport->devices)
 928                port->physport->devices->prev = par_dev;
 929        port->physport->devices = par_dev;
 930        spin_unlock(&port->physport->pardevice_lock);
 931
 932        init_waitqueue_head(&par_dev->wait_q);
 933        par_dev->timeslice = parport_default_timeslice;
 934        par_dev->waitnext = NULL;
 935        par_dev->waitprev = NULL;
 936
 937        /*
 938         * This has to be run as last thing since init_state may need other
 939         * pardevice fields. -arca
 940         */
 941        port->ops->init_state(par_dev, par_dev->state);
 942        port->proc_device = par_dev;
 943        parport_device_proc_register(par_dev);
 944
 945        return par_dev;
 946
 947err_free_devname:
 948        kfree(devname);
 949err_free_par_dev:
 950        kfree(par_dev->state);
 951err_put_par_dev:
 952        if (!par_dev->devmodel)
 953                kfree(par_dev);
 954err_put_port:
 955        parport_put_port(port);
 956        module_put(port->ops->owner);
 957
 958        return NULL;
 959}
 960EXPORT_SYMBOL(parport_register_dev_model);
 961
 962/**
 963 *      parport_unregister_device - deregister a device on a parallel port
 964 *      @dev: pointer to structure representing device
 965 *
 966 *      This undoes the effect of parport_register_device().
 967 **/
 968
 969void parport_unregister_device(struct pardevice *dev)
 970{
 971        struct parport *port;
 972
 973#ifdef PARPORT_PARANOID
 974        if (!dev) {
 975                printk(KERN_ERR "parport_unregister_device: passed NULL\n");
 976                return;
 977        }
 978#endif
 979
 980        port = dev->port->physport;
 981
 982        if (port->proc_device == dev) {
 983                port->proc_device = NULL;
 984                clear_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags);
 985                parport_device_proc_unregister(dev);
 986        }
 987
 988        if (port->cad == dev) {
 989                printk(KERN_DEBUG "%s: %s forgot to release port\n",
 990                       port->name, dev->name);
 991                parport_release(dev);
 992        }
 993
 994        spin_lock(&port->pardevice_lock);
 995        if (dev->next)
 996                dev->next->prev = dev->prev;
 997        if (dev->prev)
 998                dev->prev->next = dev->next;
 999        else
1000                port->devices = dev->next;
1001
1002        if (dev->flags & PARPORT_DEV_EXCL)
1003                port->flags &= ~PARPORT_FLAG_EXCL;
1004
1005        spin_unlock(&port->pardevice_lock);
1006
1007        /*
1008         * Make sure we haven't left any pointers around in the wait
1009         * list.
1010         */
1011        spin_lock_irq(&port->waitlist_lock);
1012        if (dev->waitprev || dev->waitnext || port->waithead == dev) {
1013                if (dev->waitprev)
1014                        dev->waitprev->waitnext = dev->waitnext;
1015                else
1016                        port->waithead = dev->waitnext;
1017                if (dev->waitnext)
1018                        dev->waitnext->waitprev = dev->waitprev;
1019                else
1020                        port->waittail = dev->waitprev;
1021        }
1022        spin_unlock_irq(&port->waitlist_lock);
1023
1024        kfree(dev->state);
1025        if (dev->devmodel)
1026                device_unregister(&dev->dev);
1027        else
1028                kfree(dev);
1029
1030        module_put(port->ops->owner);
1031        parport_put_port(port);
1032}
1033EXPORT_SYMBOL(parport_unregister_device);
1034
1035/**
1036 *      parport_find_number - find a parallel port by number
1037 *      @number: parallel port number
1038 *
1039 *      This returns the parallel port with the specified number, or
1040 *      %NULL if there is none.
1041 *
1042 *      There is an implicit parport_get_port() done already; to throw
1043 *      away the reference to the port that parport_find_number()
1044 *      gives you, use parport_put_port().
1045 */
1046
1047struct parport *parport_find_number(int number)
1048{
1049        struct parport *port, *result = NULL;
1050
1051        if (list_empty(&portlist))
1052                get_lowlevel_driver();
1053
1054        spin_lock(&parportlist_lock);
1055        list_for_each_entry(port, &portlist, list) {
1056                if (port->number == number) {
1057                        result = parport_get_port(port);
1058                        break;
1059                }
1060        }
1061        spin_unlock(&parportlist_lock);
1062        return result;
1063}
1064EXPORT_SYMBOL(parport_find_number);
1065
1066/**
1067 *      parport_find_base - find a parallel port by base address
1068 *      @base: base I/O address
1069 *
1070 *      This returns the parallel port with the specified base
1071 *      address, or %NULL if there is none.
1072 *
1073 *      There is an implicit parport_get_port() done already; to throw
1074 *      away the reference to the port that parport_find_base()
1075 *      gives you, use parport_put_port().
1076 */
1077
1078struct parport *parport_find_base(unsigned long base)
1079{
1080        struct parport *port, *result = NULL;
1081
1082        if (list_empty(&portlist))
1083                get_lowlevel_driver();
1084
1085        spin_lock(&parportlist_lock);
1086        list_for_each_entry(port, &portlist, list) {
1087                if (port->base == base) {
1088                        result = parport_get_port(port);
1089                        break;
1090                }
1091        }
1092        spin_unlock(&parportlist_lock);
1093        return result;
1094}
1095EXPORT_SYMBOL(parport_find_base);
1096
1097/**
1098 *      parport_claim - claim access to a parallel port device
1099 *      @dev: pointer to structure representing a device on the port
1100 *
1101 *      This function will not block and so can be used from interrupt
1102 *      context.  If parport_claim() succeeds in claiming access to
1103 *      the port it returns zero and the port is available to use.  It
1104 *      may fail (returning non-zero) if the port is in use by another
1105 *      driver and that driver is not willing to relinquish control of
1106 *      the port.
1107 **/
1108
1109int parport_claim(struct pardevice *dev)
1110{
1111        struct pardevice *oldcad;
1112        struct parport *port = dev->port->physport;
1113        unsigned long flags;
1114
1115        if (port->cad == dev) {
1116                printk(KERN_INFO "%s: %s already owner\n",
1117                       dev->port->name,dev->name);
1118                return 0;
1119        }
1120
1121        /* Preempt any current device */
1122        write_lock_irqsave(&port->cad_lock, flags);
1123        oldcad = port->cad;
1124        if (oldcad) {
1125                if (oldcad->preempt) {
1126                        if (oldcad->preempt(oldcad->private))
1127                                goto blocked;
1128                        port->ops->save_state(port, dev->state);
1129                } else
1130                        goto blocked;
1131
1132                if (port->cad != oldcad) {
1133                        /*
1134                         * I think we'll actually deadlock rather than
1135                         * get here, but just in case..
1136                         */
1137                        printk(KERN_WARNING
1138                               "%s: %s released port when preempted!\n",
1139                               port->name, oldcad->name);
1140                        if (port->cad)
1141                                goto blocked;
1142                }
1143        }
1144
1145        /* Can't fail from now on, so mark ourselves as no longer waiting.  */
1146        if (dev->waiting & 1) {
1147                dev->waiting = 0;
1148
1149                /* Take ourselves out of the wait list again.  */
1150                spin_lock_irq(&port->waitlist_lock);
1151                if (dev->waitprev)
1152                        dev->waitprev->waitnext = dev->waitnext;
1153                else
1154                        port->waithead = dev->waitnext;
1155                if (dev->waitnext)
1156                        dev->waitnext->waitprev = dev->waitprev;
1157                else
1158                        port->waittail = dev->waitprev;
1159                spin_unlock_irq(&port->waitlist_lock);
1160                dev->waitprev = dev->waitnext = NULL;
1161        }
1162
1163        /* Now we do the change of devices */
1164        port->cad = dev;
1165
1166#ifdef CONFIG_PARPORT_1284
1167        /* If it's a mux port, select it. */
1168        if (dev->port->muxport >= 0) {
1169                /* FIXME */
1170                port->muxsel = dev->port->muxport;
1171        }
1172
1173        /* If it's a daisy chain device, select it. */
1174        if (dev->daisy >= 0) {
1175                /* This could be lazier. */
1176                if (!parport_daisy_select(port, dev->daisy,
1177                                           IEEE1284_MODE_COMPAT))
1178                        port->daisy = dev->daisy;
1179        }
1180#endif /* IEEE1284.3 support */
1181
1182        /* Restore control registers */
1183        port->ops->restore_state(port, dev->state);
1184        write_unlock_irqrestore(&port->cad_lock, flags);
1185        dev->time = jiffies;
1186        return 0;
1187
1188blocked:
1189        /*
1190         * If this is the first time we tried to claim the port, register an
1191         * interest.  This is only allowed for devices sleeping in
1192         * parport_claim_or_block(), or those with a wakeup function.
1193         */
1194
1195        /* The cad_lock is still held for writing here */
1196        if (dev->waiting & 2 || dev->wakeup) {
1197                spin_lock(&port->waitlist_lock);
1198                if (test_and_set_bit(0, &dev->waiting) == 0) {
1199                        /* First add ourselves to the end of the wait list. */
1200                        dev->waitnext = NULL;
1201                        dev->waitprev = port->waittail;
1202                        if (port->waittail) {
1203                                port->waittail->waitnext = dev;
1204                                port->waittail = dev;
1205                        } else
1206                                port->waithead = port->waittail = dev;
1207                }
1208                spin_unlock(&port->waitlist_lock);
1209        }
1210        write_unlock_irqrestore(&port->cad_lock, flags);
1211        return -EAGAIN;
1212}
1213EXPORT_SYMBOL(parport_claim);
1214
1215/**
1216 *      parport_claim_or_block - claim access to a parallel port device
1217 *      @dev: pointer to structure representing a device on the port
1218 *
1219 *      This behaves like parport_claim(), but will block if necessary
1220 *      to wait for the port to be free.  A return value of 1
1221 *      indicates that it slept; 0 means that it succeeded without
1222 *      needing to sleep.  A negative error code indicates failure.
1223 **/
1224
1225int parport_claim_or_block(struct pardevice *dev)
1226{
1227        int r;
1228
1229        /*
1230         * Signal to parport_claim() that we can wait even without a
1231         * wakeup function.
1232         */
1233        dev->waiting = 2;
1234
1235        /* Try to claim the port.  If this fails, we need to sleep.  */
1236        r = parport_claim(dev);
1237        if (r == -EAGAIN) {
1238#ifdef PARPORT_DEBUG_SHARING
1239                printk(KERN_DEBUG "%s: parport_claim() returned -EAGAIN\n", dev->name);
1240#endif
1241                /*
1242                 * FIXME!!! Use the proper locking for dev->waiting,
1243                 * and make this use the "wait_event_interruptible()"
1244                 * interfaces. The cli/sti that used to be here
1245                 * did nothing.
1246                 *
1247                 * See also parport_release()
1248                 */
1249
1250                /*
1251                 * If dev->waiting is clear now, an interrupt
1252                 * gave us the port and we would deadlock if we slept.
1253                 */
1254                if (dev->waiting) {
1255                        wait_event_interruptible(dev->wait_q,
1256                                                 !dev->waiting);
1257                        if (signal_pending(current))
1258                                return -EINTR;
1259                        r = 1;
1260                } else {
1261                        r = 0;
1262#ifdef PARPORT_DEBUG_SHARING
1263                        printk(KERN_DEBUG "%s: didn't sleep in parport_claim_or_block()\n",
1264                               dev->name);
1265#endif
1266                }
1267
1268#ifdef PARPORT_DEBUG_SHARING
1269                if (dev->port->physport->cad != dev)
1270                        printk(KERN_DEBUG "%s: exiting parport_claim_or_block but %s owns port!\n",
1271                               dev->name, dev->port->physport->cad ?
1272                               dev->port->physport->cad->name:"nobody");
1273#endif
1274        }
1275        dev->waiting = 0;
1276        return r;
1277}
1278EXPORT_SYMBOL(parport_claim_or_block);
1279
1280/**
1281 *      parport_release - give up access to a parallel port device
1282 *      @dev: pointer to structure representing parallel port device
1283 *
1284 *      This function cannot fail, but it should not be called without
1285 *      the port claimed.  Similarly, if the port is already claimed
1286 *      you should not try claiming it again.
1287 **/
1288
1289void parport_release(struct pardevice *dev)
1290{
1291        struct parport *port = dev->port->physport;
1292        struct pardevice *pd;
1293        unsigned long flags;
1294
1295        /* Make sure that dev is the current device */
1296        write_lock_irqsave(&port->cad_lock, flags);
1297        if (port->cad != dev) {
1298                write_unlock_irqrestore(&port->cad_lock, flags);
1299                printk(KERN_WARNING "%s: %s tried to release parport when not owner\n",
1300                       port->name, dev->name);
1301                return;
1302        }
1303
1304#ifdef CONFIG_PARPORT_1284
1305        /* If this is on a mux port, deselect it. */
1306        if (dev->port->muxport >= 0) {
1307                /* FIXME */
1308                port->muxsel = -1;
1309        }
1310
1311        /* If this is a daisy device, deselect it. */
1312        if (dev->daisy >= 0) {
1313                parport_daisy_deselect_all(port);
1314                port->daisy = -1;
1315        }
1316#endif
1317
1318        port->cad = NULL;
1319        write_unlock_irqrestore(&port->cad_lock, flags);
1320
1321        /* Save control registers */
1322        port->ops->save_state(port, dev->state);
1323
1324        /*
1325         * If anybody is waiting, find out who's been there longest and
1326         * then wake them up. (Note: no locking required)
1327         */
1328        /* !!! LOCKING IS NEEDED HERE */
1329        for (pd = port->waithead; pd; pd = pd->waitnext) {
1330                if (pd->waiting & 2) { /* sleeping in claim_or_block */
1331                        parport_claim(pd);
1332                        if (waitqueue_active(&pd->wait_q))
1333                                wake_up_interruptible(&pd->wait_q);
1334                        return;
1335                } else if (pd->wakeup) {
1336                        pd->wakeup(pd->private);
1337                        if (dev->port->cad) /* racy but no matter */
1338                                return;
1339                } else {
1340                        printk(KERN_ERR "%s: don't know how to wake %s\n", port->name, pd->name);
1341                }
1342        }
1343
1344        /*
1345         * Nobody was waiting, so walk the list to see if anyone is
1346         * interested in being woken up. (Note: no locking required)
1347         */
1348        /* !!! LOCKING IS NEEDED HERE */
1349        for (pd = port->devices; !port->cad && pd; pd = pd->next) {
1350                if (pd->wakeup && pd != dev)
1351                        pd->wakeup(pd->private);
1352        }
1353}
1354EXPORT_SYMBOL(parport_release);
1355
1356irqreturn_t parport_irq_handler(int irq, void *dev_id)
1357{
1358        struct parport *port = dev_id;
1359
1360        parport_generic_irq(port);
1361
1362        return IRQ_HANDLED;
1363}
1364EXPORT_SYMBOL(parport_irq_handler);
1365
1366MODULE_LICENSE("GPL");
1367