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 #ifdef DEBUG
  34 #define DPRINTK(stuff...) printk(stuff)
  35 #else
  36 #define DPRINTK(stuff...)
  37 #endif
  38
  39 static struct daisydev {
  40         struct daisydev *next;
  41         struct parport *port;
  42         int daisy;
  43         int devnum;
  44 } *topology = NULL;
  45 static DEFINE_SPINLOCK(topology_lock);
  46
  47 static int numdevs;
  48 static bool daisy_init_done;
  49
  50 /* Forward-declaration of lower-level functions. */
  51 static int mux_present(struct parport *port);
  52 static int num_mux_ports(struct parport *port);
  53 static int select_port(struct parport *port);
  54 static int assign_addrs(struct parport *port);
  55
  56 /* Add a device to the discovered topology. */
  57 static void add_dev(int devnum, struct parport *port, int daisy)
  58 {
  59         struct daisydev *newdev, **p;
  60         newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
  61         if (newdev) {
  62                 newdev->port = port;
  63                 newdev->daisy = daisy;
  64                 newdev->devnum = devnum;
  65                 spin_lock(&topology_lock);
  66                 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
  67                         ;
  68                 newdev->next = *p;
  69                 *p = newdev;
  70                 spin_unlock(&topology_lock);
  71         }
  72 }
  73
  74 /* Clone a parport (actually, make an alias). */
  75 static struct parport *clone_parport(struct parport *real, int muxport)
  76 {
  77         struct parport *extra = parport_register_port(real->base,
  78                                                        real->irq,
  79                                                        real->dma,
  80                                                        real->ops);
  81         if (extra) {
  82                 extra->portnum = real->portnum;
  83                 extra->physport = real;
  84                 extra->muxport = muxport;
  85                 real->slaves[muxport-1] = extra;
  86         }
  87
  88         return extra;
  89 }
  90
  91 static int daisy_drv_probe(struct pardevice *par_dev)
  92 {
  93         struct device_driver *drv = par_dev->dev.driver;
  94
  95         if (strcmp(drv->name, "daisy_drv"))
  96                 return -ENODEV;
  97         if (strcmp(par_dev->name, daisy_dev_name))
  98                 return -ENODEV;
  99
 100         return 0;
 101 }
 102
 103 static struct parport_driver daisy_driver = {
 104         .name = "daisy_drv",
 105         .probe = daisy_drv_probe,
 106         .devmodel = true,
 107 };
 108
 109 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
 110  * Return value is number of devices actually detected. */
 111 int parport_daisy_init(struct parport *port)
 112 {
 113         int detected = 0;
 114         char *deviceid;
 115         static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
 116         int num_ports;
 117         int i;
 118         int last_try = 0;
 119
 120         if (!daisy_init_done) {
 121                 /*
 122                  * flag should be marked true first as
 123                  * parport_register_driver() might try to load the low
 124                  * level driver which will lead to announcing new ports
 125                  * and which will again come back here at
 126                  * parport_daisy_init()
 127                  */
 128                 daisy_init_done = true;
 129                 i = parport_register_driver(&daisy_driver);
 130                 if (i) {
 131                         pr_err("daisy registration failed\n");
 132                         daisy_init_done = false;
 133                         return i;
 134                 }
 135         }
 136
 137 again:
 138         /* Because this is called before any other devices exist,
 139          * we don't have to claim exclusive access.  */
 140
 141         /* If mux present on normal port, need to create new
 142          * parports for each extra port. */
 143         if (port->muxport < 0 && mux_present(port) &&
 144             /* don't be fooled: a mux must have 2 or 4 ports. */
 145             ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
 146                 /* Leave original as port zero. */
 147                 port->muxport = 0;
 148                 printk(KERN_INFO
 149                         "%s: 1st (default) port of %d-way multiplexor\n",
 150                         port->name, num_ports);
 151                 for (i = 1; i < num_ports; i++) {
 152                         /* Clone the port. */
 153                         struct parport *extra = clone_parport(port, i);
 154                         if (!extra) {
 155                                 if (signal_pending(current))
 156                                         break;
 157
 158                                 schedule();
 159                                 continue;
 160                         }
 161
 162                         printk(KERN_INFO
 163                                 "%s: %d%s port of %d-way multiplexor on %s\n",
 164                                 extra->name, i + 1, th[i + 1], num_ports,
 165                                 port->name);
 166
 167                         /* Analyse that port too.  We won't recurse
 168                            forever because of the 'port->muxport < 0'
 169                            test above. */
 170                         parport_daisy_init(extra);
 171                 }
 172         }
 173
 174         if (port->muxport >= 0)
 175                 select_port(port);
 176
 177         parport_daisy_deselect_all(port);
 178         detected += assign_addrs(port);
 179
 180         /* Count the potential legacy device at the end. */
 181         add_dev(numdevs++, port, -1);
 182
 183         /* Find out the legacy device's IEEE 1284 device ID. */
 184         deviceid = kmalloc(1024, GFP_KERNEL);
 185         if (deviceid) {
 186                 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
 187                         detected++;
 188
 189                 kfree(deviceid);
 190         }
 191
 192         if (!detected && !last_try) {
 193                 /* No devices were detected.  Perhaps they are in some
 194                    funny state; let's try to reset them and see if
 195                    they wake up. */
 196                 parport_daisy_fini(port);
 197                 parport_write_control(port, PARPORT_CONTROL_SELECT);
 198                 udelay(50);
 199                 parport_write_control(port,
 200                                        PARPORT_CONTROL_SELECT |
 201                                        PARPORT_CONTROL_INIT);
 202                 udelay(50);
 203                 last_try = 1;
 204                 goto again;
 205         }
 206
 207         return detected;
 208 }
 209
 210 /* Forget about devices on a physical port. */
 211 void parport_daisy_fini(struct parport *port)
 212 {
 213         struct daisydev **p;
 214
 215         spin_lock(&topology_lock);
 216         p = &topology;
 217         while (*p) {
 218                 struct daisydev *dev = *p;
 219                 if (dev->port != port) {
 220                         p = &dev->next;
 221                         continue;
 222                 }
 223                 *p = dev->next;
 224                 kfree(dev);
 225         }
 226
 227         /* Gaps in the numbering could be handled better.  How should
 228            someone enumerate through all IEEE1284.3 devices in the
 229            topology?. */
 230         if (!topology) numdevs = 0;
 231         spin_unlock(&topology_lock);
 232         return;
 233 }
 234
 235 /**
 236  *      parport_open - find a device by canonical device number
 237  *      @devnum: canonical device number
 238  *      @name: name to associate with the device
 239  *
 240  *      This function is similar to parport_register_device(), except
 241  *      that it locates a device by its number rather than by the port
 242  *      it is attached to.
 243  *
 244  *      All parameters except for @devnum are the same as for
 245  *      parport_register_device().  The return value is the same as
 246  *      for parport_register_device().
 247  **/
 248
 249 struct pardevice *parport_open(int devnum, const char *name)
 250 {
 251         struct daisydev *p = topology;
 252         struct pardev_cb par_cb;
 253         struct parport *port;
 254         struct pardevice *dev;
 255         int daisy;
 256
 257         memset(&par_cb, 0, sizeof(par_cb));
 258         spin_lock(&topology_lock);
 259         while (p && p->devnum != devnum)
 260                 p = p->next;
 261
 262         if (!p) {
 263                 spin_unlock(&topology_lock);
 264                 return NULL;
 265         }
 266
 267         daisy = p->daisy;
 268         port = parport_get_port(p->port);
 269         spin_unlock(&topology_lock);
 270
 271         dev = parport_register_dev_model(port, name, &par_cb, devnum);
 272         parport_put_port(port);
 273         if (!dev)
 274                 return NULL;
 275
 276         dev->daisy = daisy;
 277
 278         /* Check that there really is a device to select. */
 279         if (daisy >= 0) {
 280                 int selected;
 281                 parport_claim_or_block(dev);
 282                 selected = port->daisy;
 283                 parport_release(dev);
 284
 285                 if (selected != daisy) {
 286                         /* No corresponding device. */
 287                         parport_unregister_device(dev);
 288                         return NULL;
 289                 }
 290         }
 291
 292         return dev;
 293 }
 294
 295 /**
 296  *      parport_close - close a device opened with parport_open()
 297  *      @dev: device to close
 298  *
 299  *      This is to parport_open() as parport_unregister_device() is to
 300  *      parport_register_device().
 301  **/
 302
 303 void parport_close(struct pardevice *dev)
 304 {
 305         parport_unregister_device(dev);
 306 }
 307
 308 /* Send a daisy-chain-style CPP command packet. */
 309 static int cpp_daisy(struct parport *port, int cmd)
 310 {
 311         unsigned char s;
 312
 313         parport_data_forward(port);
 314         parport_write_data(port, 0xaa); udelay(2);
 315         parport_write_data(port, 0x55); udelay(2);
 316         parport_write_data(port, 0x00); udelay(2);
 317         parport_write_data(port, 0xff); udelay(2);
 318         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 319                                           | PARPORT_STATUS_PAPEROUT
 320                                           | PARPORT_STATUS_SELECT
 321                                           | PARPORT_STATUS_ERROR);
 322         if (s != (PARPORT_STATUS_BUSY
 323                   | PARPORT_STATUS_PAPEROUT
 324                   | PARPORT_STATUS_SELECT
 325                   | PARPORT_STATUS_ERROR)) {
 326                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
 327                          port->name, s);
 328                 return -ENXIO;
 329         }
 330
 331         parport_write_data(port, 0x87); udelay(2);
 332         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 333                                           | PARPORT_STATUS_PAPEROUT
 334                                           | PARPORT_STATUS_SELECT
 335                                           | PARPORT_STATUS_ERROR);
 336         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 337                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
 338                          port->name, s);
 339                 return -ENXIO;
 340         }
 341
 342         parport_write_data(port, 0x78); udelay(2);
 343         parport_write_data(port, cmd); udelay(2);
 344         parport_frob_control(port,
 345                               PARPORT_CONTROL_STROBE,
 346                               PARPORT_CONTROL_STROBE);
 347         udelay(1);
 348         s = parport_read_status(port);
 349         parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 350         udelay(1);
 351         parport_write_data(port, 0xff); udelay(2);
 352
 353         return s;
 354 }
 355
 356 /* Send a mux-style CPP command packet. */
 357 static int cpp_mux(struct parport *port, int cmd)
 358 {
 359         unsigned char s;
 360         int rc;
 361
 362         parport_data_forward(port);
 363         parport_write_data(port, 0xaa); udelay(2);
 364         parport_write_data(port, 0x55); udelay(2);
 365         parport_write_data(port, 0xf0); udelay(2);
 366         parport_write_data(port, 0x0f); udelay(2);
 367         parport_write_data(port, 0x52); udelay(2);
 368         parport_write_data(port, 0xad); udelay(2);
 369         parport_write_data(port, cmd); udelay(2);
 370
 371         s = parport_read_status(port);
 372         if (!(s & PARPORT_STATUS_ACK)) {
 373                 DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
 374                          port->name, cmd, s);
 375                 return -EIO;
 376         }
 377
 378         rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
 379               ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
 380               ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
 381               ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
 382
 383         return rc;
 384 }
 385
 386 void parport_daisy_deselect_all(struct parport *port)
 387 {
 388         cpp_daisy(port, 0x30);
 389 }
 390
 391 int parport_daisy_select(struct parport *port, int daisy, int mode)
 392 {
 393         switch (mode)
 394         {
 395                 // For these modes we should switch to EPP mode:
 396                 case IEEE1284_MODE_EPP:
 397                 case IEEE1284_MODE_EPPSL:
 398                 case IEEE1284_MODE_EPPSWE:
 399                         return !(cpp_daisy(port, 0x20 + daisy) &
 400                                  PARPORT_STATUS_ERROR);
 401
 402                 // For these modes we should switch to ECP mode:
 403                 case IEEE1284_MODE_ECP:
 404                 case IEEE1284_MODE_ECPRLE:
 405                 case IEEE1284_MODE_ECPSWE:
 406                         return !(cpp_daisy(port, 0xd0 + daisy) &
 407                                  PARPORT_STATUS_ERROR);
 408
 409                 // Nothing was told for BECP in Daisy chain specification.
 410                 // May be it's wise to use ECP?
 411                 case IEEE1284_MODE_BECP:
 412                 // Others use compat mode
 413                 case IEEE1284_MODE_NIBBLE:
 414                 case IEEE1284_MODE_BYTE:
 415                 case IEEE1284_MODE_COMPAT:
 416                 default:
 417                         return !(cpp_daisy(port, 0xe0 + daisy) &
 418                                  PARPORT_STATUS_ERROR);
 419         }
 420 }
 421
 422 static int mux_present(struct parport *port)
 423 {
 424         return cpp_mux(port, 0x51) == 3;
 425 }
 426
 427 static int num_mux_ports(struct parport *port)
 428 {
 429         return cpp_mux(port, 0x58);
 430 }
 431
 432 static int select_port(struct parport *port)
 433 {
 434         int muxport = port->muxport;
 435         return cpp_mux(port, 0x60 + muxport) == muxport;
 436 }
 437
 438 static int assign_addrs(struct parport *port)
 439 {
 440         unsigned char s;
 441         unsigned char daisy;
 442         int thisdev = numdevs;
 443         int detected;
 444         char *deviceid;
 445
 446         parport_data_forward(port);
 447         parport_write_data(port, 0xaa); udelay(2);
 448         parport_write_data(port, 0x55); udelay(2);
 449         parport_write_data(port, 0x00); udelay(2);
 450         parport_write_data(port, 0xff); udelay(2);
 451         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 452                                           | PARPORT_STATUS_PAPEROUT
 453                                           | PARPORT_STATUS_SELECT
 454                                           | PARPORT_STATUS_ERROR);
 455         if (s != (PARPORT_STATUS_BUSY
 456                   | PARPORT_STATUS_PAPEROUT
 457                   | PARPORT_STATUS_SELECT
 458                   | PARPORT_STATUS_ERROR)) {
 459                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
 460                          port->name, s);
 461                 return 0;
 462         }
 463
 464         parport_write_data(port, 0x87); udelay(2);
 465         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 466                                           | PARPORT_STATUS_PAPEROUT
 467                                           | PARPORT_STATUS_SELECT
 468                                           | PARPORT_STATUS_ERROR);
 469         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 470                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
 471                          port->name, s);
 472                 return 0;
 473         }
 474
 475         parport_write_data(port, 0x78); udelay(2);
 476         s = parport_read_status(port);
 477
 478         for (daisy = 0;
 479              (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
 480                      == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
 481                      && daisy < 4;
 482              ++daisy) {
 483                 parport_write_data(port, daisy);
 484                 udelay(2);
 485                 parport_frob_control(port,
 486                                       PARPORT_CONTROL_STROBE,
 487                                       PARPORT_CONTROL_STROBE);
 488                 udelay(1);
 489                 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 490                 udelay(1);
 491
 492                 add_dev(numdevs++, port, daisy);
 493
 494                 /* See if this device thought it was the last in the
 495                  * chain. */
 496                 if (!(s & PARPORT_STATUS_BUSY))
 497                         break;
 498
 499                 /* We are seeing pass through status now. We see
 500                    last_dev from next device or if last_dev does not
 501                    work status lines from some non-daisy chain
 502                    device. */
 503                 s = parport_read_status(port);
 504         }
 505
 506         parport_write_data(port, 0xff); udelay(2);
 507         detected = numdevs - thisdev;
 508         DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
 509                  detected);
 510
 511         /* Ask the new devices to introduce themselves. */
 512         deviceid = kmalloc(1024, GFP_KERNEL);
 513         if (!deviceid) return 0;
 514
 515         for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
 516                 parport_device_id(thisdev, deviceid, 1024);
 517
 518         kfree(deviceid);
 519         return detected;
 520 }