drivers/parport/daisy.c

   1 /*
   2  * IEEE 1284.3 Parallel port daisy chain and multiplexor code
   3  *
   4  * Copyright (C) 1999, 2000  Tim Waugh <tim@cyberelk.demon.co.uk>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  *
  11  * ??-12-1998: Initial implementation.
  12  * 31-01-1999: Make port-cloning transparent.
  13  * 13-02-1999: Move DeviceID technique from parport_probe.
  14  * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
  15  * 22-02-2000: Count devices that are actually detected.
  16  *
  17  * Any part of this program may be used in documents licensed under
  18  * the GNU Free Documentation License, Version 1.1 or any later version
  19  * published by the Free Software Foundation.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/parport.h>
  24 #include <linux/delay.h>
  25 #include <linux/slab.h>
  26 #include <linux/sched/signal.h>
  27
  28 #include <asm/current.h>
  29 #include <linux/uaccess.h>
  30
  31 #undef DEBUG
  32
  33 static struct daisydev {
  34         struct daisydev *next;
  35         struct parport *port;
  36         int daisy;
  37         int devnum;
  38 } *topology = NULL;
  39 static DEFINE_SPINLOCK(topology_lock);
  40
  41 static int numdevs;
  42 static bool daisy_init_done;
  43
  44 /* Forward-declaration of lower-level functions. */
  45 static int mux_present(struct parport *port);
  46 static int num_mux_ports(struct parport *port);
  47 static int select_port(struct parport *port);
  48 static int assign_addrs(struct parport *port);
  49
  50 /* Add a device to the discovered topology. */
  51 static void add_dev(int devnum, struct parport *port, int daisy)
  52 {
  53         struct daisydev *newdev, **p;
  54         newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
  55         if (newdev) {
  56                 newdev->port = port;
  57                 newdev->daisy = daisy;
  58                 newdev->devnum = devnum;
  59                 spin_lock(&topology_lock);
  60                 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
  61                         ;
  62                 newdev->next = *p;
  63                 *p = newdev;
  64                 spin_unlock(&topology_lock);
  65         }
  66 }
  67
  68 /* Clone a parport (actually, make an alias). */
  69 static struct parport *clone_parport(struct parport *real, int muxport)
  70 {
  71         struct parport *extra = parport_register_port(real->base,
  72                                                        real->irq,
  73                                                        real->dma,
  74                                                        real->ops);
  75         if (extra) {
  76                 extra->portnum = real->portnum;
  77                 extra->physport = real;
  78                 extra->muxport = muxport;
  79                 real->slaves[muxport-1] = extra;
  80         }
  81
  82         return extra;
  83 }
  84
  85 static int daisy_drv_probe(struct pardevice *par_dev)
  86 {
  87         struct device_driver *drv = par_dev->dev.driver;
  88
  89         if (strcmp(drv->name, "daisy_drv"))
  90                 return -ENODEV;
  91         if (strcmp(par_dev->name, daisy_dev_name))
  92                 return -ENODEV;
  93
  94         return 0;
  95 }
  96
  97 static struct parport_driver daisy_driver = {
  98         .name = "daisy_drv",
  99         .probe = daisy_drv_probe,
 100         .devmodel = true,
 101 };
 102
 103 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
 104  * Return value is number of devices actually detected. */
 105 int parport_daisy_init(struct parport *port)
 106 {
 107         int detected = 0;
 108         char *deviceid;
 109         static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
 110         int num_ports;
 111         int i;
 112         int last_try = 0;
 113
 114         if (!daisy_init_done) {
 115                 /*
 116                  * flag should be marked true first as
 117                  * parport_register_driver() might try to load the low
 118                  * level driver which will lead to announcing new ports
 119                  * and which will again come back here at
 120                  * parport_daisy_init()
 121                  */
 122                 daisy_init_done = true;
 123                 i = parport_register_driver(&daisy_driver);
 124                 if (i) {
 125                         pr_err("daisy registration failed\n");
 126                         daisy_init_done = false;
 127                         return i;
 128                 }
 129         }
 130
 131 again:
 132         /* Because this is called before any other devices exist,
 133          * we don't have to claim exclusive access.  */
 134
 135         /* If mux present on normal port, need to create new
 136          * parports for each extra port. */
 137         if (port->muxport < 0 && mux_present(port) &&
 138             /* don't be fooled: a mux must have 2 or 4 ports. */
 139             ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
 140                 /* Leave original as port zero. */
 141                 port->muxport = 0;
 142                 pr_info("%s: 1st (default) port of %d-way multiplexor\n",
 143                         port->name, num_ports);
 144                 for (i = 1; i < num_ports; i++) {
 145                         /* Clone the port. */
 146                         struct parport *extra = clone_parport(port, i);
 147                         if (!extra) {
 148                                 if (signal_pending(current))
 149                                         break;
 150
 151                                 schedule();
 152                                 continue;
 153                         }
 154
 155                         pr_info("%s: %d%s port of %d-way multiplexor on %s\n",
 156                                 extra->name, i + 1, th[i + 1], num_ports,
 157                                 port->name);
 158
 159                         /* Analyse that port too.  We won't recurse
 160                            forever because of the 'port->muxport < 0'
 161                            test above. */
 162                         parport_daisy_init(extra);
 163                 }
 164         }
 165
 166         if (port->muxport >= 0)
 167                 select_port(port);
 168
 169         parport_daisy_deselect_all(port);
 170         detected += assign_addrs(port);
 171
 172         /* Count the potential legacy device at the end. */
 173         add_dev(numdevs++, port, -1);
 174
 175         /* Find out the legacy device's IEEE 1284 device ID. */
 176         deviceid = kmalloc(1024, GFP_KERNEL);
 177         if (deviceid) {
 178                 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
 179                         detected++;
 180
 181                 kfree(deviceid);
 182         }
 183
 184         if (!detected && !last_try) {
 185                 /* No devices were detected.  Perhaps they are in some
 186                    funny state; let's try to reset them and see if
 187                    they wake up. */
 188                 parport_daisy_fini(port);
 189                 parport_write_control(port, PARPORT_CONTROL_SELECT);
 190                 udelay(50);
 191                 parport_write_control(port,
 192                                        PARPORT_CONTROL_SELECT |
 193                                        PARPORT_CONTROL_INIT);
 194                 udelay(50);
 195                 last_try = 1;
 196                 goto again;
 197         }
 198
 199         return detected;
 200 }
 201
 202 /* Forget about devices on a physical port. */
 203 void parport_daisy_fini(struct parport *port)
 204 {
 205         struct daisydev **p;
 206
 207         spin_lock(&topology_lock);
 208         p = &topology;
 209         while (*p) {
 210                 struct daisydev *dev = *p;
 211                 if (dev->port != port) {
 212                         p = &dev->next;
 213                         continue;
 214                 }
 215                 *p = dev->next;
 216                 kfree(dev);
 217         }
 218
 219         /* Gaps in the numbering could be handled better.  How should
 220            someone enumerate through all IEEE1284.3 devices in the
 221            topology?. */
 222         if (!topology) numdevs = 0;
 223         spin_unlock(&topology_lock);
 224         return;
 225 }
 226
 227 /**
 228  *      parport_open - find a device by canonical device number
 229  *      @devnum: canonical device number
 230  *      @name: name to associate with the device
 231  *
 232  *      This function is similar to parport_register_device(), except
 233  *      that it locates a device by its number rather than by the port
 234  *      it is attached to.
 235  *
 236  *      All parameters except for @devnum are the same as for
 237  *      parport_register_device().  The return value is the same as
 238  *      for parport_register_device().
 239  **/
 240
 241 struct pardevice *parport_open(int devnum, const char *name)
 242 {
 243         struct daisydev *p = topology;
 244         struct pardev_cb par_cb;
 245         struct parport *port;
 246         struct pardevice *dev;
 247         int daisy;
 248
 249         memset(&par_cb, 0, sizeof(par_cb));
 250         spin_lock(&topology_lock);
 251         while (p && p->devnum != devnum)
 252                 p = p->next;
 253
 254         if (!p) {
 255                 spin_unlock(&topology_lock);
 256                 return NULL;
 257         }
 258
 259         daisy = p->daisy;
 260         port = parport_get_port(p->port);
 261         spin_unlock(&topology_lock);
 262
 263         dev = parport_register_dev_model(port, name, &par_cb, devnum);
 264         parport_put_port(port);
 265         if (!dev)
 266                 return NULL;
 267
 268         dev->daisy = daisy;
 269
 270         /* Check that there really is a device to select. */
 271         if (daisy >= 0) {
 272                 int selected;
 273                 parport_claim_or_block(dev);
 274                 selected = port->daisy;
 275                 parport_release(dev);
 276
 277                 if (selected != daisy) {
 278                         /* No corresponding device. */
 279                         parport_unregister_device(dev);
 280                         return NULL;
 281                 }
 282         }
 283
 284         return dev;
 285 }
 286
 287 /**
 288  *      parport_close - close a device opened with parport_open()
 289  *      @dev: device to close
 290  *
 291  *      This is to parport_open() as parport_unregister_device() is to
 292  *      parport_register_device().
 293  **/
 294
 295 void parport_close(struct pardevice *dev)
 296 {
 297         parport_unregister_device(dev);
 298 }
 299
 300 /* Send a daisy-chain-style CPP command packet. */
 301 static int cpp_daisy(struct parport *port, int cmd)
 302 {
 303         unsigned char s;
 304
 305         parport_data_forward(port);
 306         parport_write_data(port, 0xaa); udelay(2);
 307         parport_write_data(port, 0x55); udelay(2);
 308         parport_write_data(port, 0x00); udelay(2);
 309         parport_write_data(port, 0xff); udelay(2);
 310         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 311                                           | PARPORT_STATUS_PAPEROUT
 312                                           | PARPORT_STATUS_SELECT
 313                                           | PARPORT_STATUS_ERROR);
 314         if (s != (PARPORT_STATUS_BUSY
 315                   | PARPORT_STATUS_PAPEROUT
 316                   | PARPORT_STATUS_SELECT
 317                   | PARPORT_STATUS_ERROR)) {
 318                 pr_debug("%s: cpp_daisy: aa5500ff(%02x)\n", port->name, s);
 319                 return -ENXIO;
 320         }
 321
 322         parport_write_data(port, 0x87); udelay(2);
 323         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 324                                           | PARPORT_STATUS_PAPEROUT
 325                                           | PARPORT_STATUS_SELECT
 326                                           | PARPORT_STATUS_ERROR);
 327         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 328                 pr_debug("%s: cpp_daisy: aa5500ff87(%02x)\n", port->name, s);
 329                 return -ENXIO;
 330         }
 331
 332         parport_write_data(port, 0x78); udelay(2);
 333         parport_write_data(port, cmd); udelay(2);
 334         parport_frob_control(port,
 335                               PARPORT_CONTROL_STROBE,
 336                               PARPORT_CONTROL_STROBE);
 337         udelay(1);
 338         s = parport_read_status(port);
 339         parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 340         udelay(1);
 341         parport_write_data(port, 0xff); udelay(2);
 342
 343         return s;
 344 }
 345
 346 /* Send a mux-style CPP command packet. */
 347 static int cpp_mux(struct parport *port, int cmd)
 348 {
 349         unsigned char s;
 350         int rc;
 351
 352         parport_data_forward(port);
 353         parport_write_data(port, 0xaa); udelay(2);
 354         parport_write_data(port, 0x55); udelay(2);
 355         parport_write_data(port, 0xf0); udelay(2);
 356         parport_write_data(port, 0x0f); udelay(2);
 357         parport_write_data(port, 0x52); udelay(2);
 358         parport_write_data(port, 0xad); udelay(2);
 359         parport_write_data(port, cmd); udelay(2);
 360
 361         s = parport_read_status(port);
 362         if (!(s & PARPORT_STATUS_ACK)) {
 363                 pr_debug("%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
 364                          port->name, cmd, s);
 365                 return -EIO;
 366         }
 367
 368         rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
 369               ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
 370               ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
 371               ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
 372
 373         return rc;
 374 }
 375
 376 void parport_daisy_deselect_all(struct parport *port)
 377 {
 378         cpp_daisy(port, 0x30);
 379 }
 380
 381 int parport_daisy_select(struct parport *port, int daisy, int mode)
 382 {
 383         switch (mode)
 384         {
 385                 // For these modes we should switch to EPP mode:
 386                 case IEEE1284_MODE_EPP:
 387                 case IEEE1284_MODE_EPPSL:
 388                 case IEEE1284_MODE_EPPSWE:
 389                         return !(cpp_daisy(port, 0x20 + daisy) &
 390                                  PARPORT_STATUS_ERROR);
 391
 392                 // For these modes we should switch to ECP mode:
 393                 case IEEE1284_MODE_ECP:
 394                 case IEEE1284_MODE_ECPRLE:
 395                 case IEEE1284_MODE_ECPSWE:
 396                         return !(cpp_daisy(port, 0xd0 + daisy) &
 397                                  PARPORT_STATUS_ERROR);
 398
 399                 // Nothing was told for BECP in Daisy chain specification.
 400                 // May be it's wise to use ECP?
 401                 case IEEE1284_MODE_BECP:
 402                 // Others use compat mode
 403                 case IEEE1284_MODE_NIBBLE:
 404                 case IEEE1284_MODE_BYTE:
 405                 case IEEE1284_MODE_COMPAT:
 406                 default:
 407                         return !(cpp_daisy(port, 0xe0 + daisy) &
 408                                  PARPORT_STATUS_ERROR);
 409         }
 410 }
 411
 412 static int mux_present(struct parport *port)
 413 {
 414         return cpp_mux(port, 0x51) == 3;
 415 }
 416
 417 static int num_mux_ports(struct parport *port)
 418 {
 419         return cpp_mux(port, 0x58);
 420 }
 421
 422 static int select_port(struct parport *port)
 423 {
 424         int muxport = port->muxport;
 425         return cpp_mux(port, 0x60 + muxport) == muxport;
 426 }
 427
 428 static int assign_addrs(struct parport *port)
 429 {
 430         unsigned char s;
 431         unsigned char daisy;
 432         int thisdev = numdevs;
 433         int detected;
 434         char *deviceid;
 435
 436         parport_data_forward(port);
 437         parport_write_data(port, 0xaa); udelay(2);
 438         parport_write_data(port, 0x55); udelay(2);
 439         parport_write_data(port, 0x00); udelay(2);
 440         parport_write_data(port, 0xff); udelay(2);
 441         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 442                                           | PARPORT_STATUS_PAPEROUT
 443                                           | PARPORT_STATUS_SELECT
 444                                           | PARPORT_STATUS_ERROR);
 445         if (s != (PARPORT_STATUS_BUSY
 446                   | PARPORT_STATUS_PAPEROUT
 447                   | PARPORT_STATUS_SELECT
 448                   | PARPORT_STATUS_ERROR)) {
 449                 pr_debug("%s: assign_addrs: aa5500ff(%02x)\n", port->name, s);
 450                 return 0;
 451         }
 452
 453         parport_write_data(port, 0x87); udelay(2);
 454         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 455                                           | PARPORT_STATUS_PAPEROUT
 456                                           | PARPORT_STATUS_SELECT
 457                                           | PARPORT_STATUS_ERROR);
 458         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 459                 pr_debug("%s: assign_addrs: aa5500ff87(%02x)\n", port->name, s);
 460                 return 0;
 461         }
 462
 463         parport_write_data(port, 0x78); udelay(2);
 464         s = parport_read_status(port);
 465
 466         for (daisy = 0;
 467              (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
 468                      == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
 469                      && daisy < 4;
 470              ++daisy) {
 471                 parport_write_data(port, daisy);
 472                 udelay(2);
 473                 parport_frob_control(port,
 474                                       PARPORT_CONTROL_STROBE,
 475                                       PARPORT_CONTROL_STROBE);
 476                 udelay(1);
 477                 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 478                 udelay(1);
 479
 480                 add_dev(numdevs++, port, daisy);
 481
 482                 /* See if this device thought it was the last in the
 483                  * chain. */
 484                 if (!(s & PARPORT_STATUS_BUSY))
 485                         break;
 486
 487                 /* We are seeing pass through status now. We see
 488                    last_dev from next device or if last_dev does not
 489                    work status lines from some non-daisy chain
 490                    device. */
 491                 s = parport_read_status(port);
 492         }
 493
 494         parport_write_data(port, 0xff); udelay(2);
 495         detected = numdevs - thisdev;
 496         pr_debug("%s: Found %d daisy-chained devices\n", port->name, detected);
 497
 498         /* Ask the new devices to introduce themselves. */
 499         deviceid = kmalloc(1024, GFP_KERNEL);
 500         if (!deviceid) return 0;
 501
 502         for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
 503                 parport_device_id(thisdev, deviceid, 1024);
 504
 505         kfree(deviceid);
 506         return detected;
 507 }