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/sched.h>
  26
  27 #include <asm/current.h>
  28 #include <asm/uaccess.h>
  29
  30 #undef DEBUG
  31
  32 #ifdef DEBUG
  33 #define DPRINTK(stuff...) printk(stuff)
  34 #else
  35 #define DPRINTK(stuff...)
  36 #endif
  37
  38 static struct daisydev {
  39         struct daisydev *next;
  40         struct parport *port;
  41         int daisy;
  42         int devnum;
  43 } *topology = NULL;
  44 static DEFINE_SPINLOCK(topology_lock);
  45
  46 static int numdevs = 0;
  47
  48 /* Forward-declaration of lower-level functions. */
  49 static int mux_present(struct parport *port);
  50 static int num_mux_ports(struct parport *port);
  51 static int select_port(struct parport *port);
  52 static int assign_addrs(struct parport *port);
  53
  54 /* Add a device to the discovered topology. */
  55 static void add_dev(int devnum, struct parport *port, int daisy)
  56 {
  57         struct daisydev *newdev, **p;
  58         newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
  59         if (newdev) {
  60                 newdev->port = port;
  61                 newdev->daisy = daisy;
  62                 newdev->devnum = devnum;
  63                 spin_lock(&topology_lock);
  64                 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
  65                         ;
  66                 newdev->next = *p;
  67                 *p = newdev;
  68                 spin_unlock(&topology_lock);
  69         }
  70 }
  71
  72 /* Clone a parport (actually, make an alias). */
  73 static struct parport *clone_parport(struct parport *real, int muxport)
  74 {
  75         struct parport *extra = parport_register_port(real->base,
  76                                                        real->irq,
  77                                                        real->dma,
  78                                                        real->ops);
  79         if (extra) {
  80                 extra->portnum = real->portnum;
  81                 extra->physport = real;
  82                 extra->muxport = muxport;
  83                 real->slaves[muxport-1] = extra;
  84         }
  85
  86         return extra;
  87 }
  88
  89 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
  90  * Return value is number of devices actually detected. */
  91 int parport_daisy_init(struct parport *port)
  92 {
  93         int detected = 0;
  94         char *deviceid;
  95         static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
  96         int num_ports;
  97         int i;
  98         int last_try = 0;
  99
 100 again:
 101         /* Because this is called before any other devices exist,
 102          * we don't have to claim exclusive access.  */
 103
 104         /* If mux present on normal port, need to create new
 105          * parports for each extra port. */
 106         if (port->muxport < 0 && mux_present(port) &&
 107             /* don't be fooled: a mux must have 2 or 4 ports. */
 108             ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
 109                 /* Leave original as port zero. */
 110                 port->muxport = 0;
 111                 printk(KERN_INFO
 112                         "%s: 1st (default) port of %d-way multiplexor\n",
 113                         port->name, num_ports);
 114                 for (i = 1; i < num_ports; i++) {
 115                         /* Clone the port. */
 116                         struct parport *extra = clone_parport(port, i);
 117                         if (!extra) {
 118                                 if (signal_pending(current))
 119                                         break;
 120
 121                                 schedule();
 122                                 continue;
 123                         }
 124
 125                         printk(KERN_INFO
 126                                 "%s: %d%s port of %d-way multiplexor on %s\n",
 127                                 extra->name, i + 1, th[i + 1], num_ports,
 128                                 port->name);
 129
 130                         /* Analyse that port too.  We won't recurse
 131                            forever because of the 'port->muxport < 0'
 132                            test above. */
 133                         parport_daisy_init(extra);
 134                 }
 135         }
 136
 137         if (port->muxport >= 0)
 138                 select_port(port);
 139
 140         parport_daisy_deselect_all(port);
 141         detected += assign_addrs(port);
 142
 143         /* Count the potential legacy device at the end. */
 144         add_dev(numdevs++, port, -1);
 145
 146         /* Find out the legacy device's IEEE 1284 device ID. */
 147         deviceid = kmalloc(1024, GFP_KERNEL);
 148         if (deviceid) {
 149                 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
 150                         detected++;
 151
 152                 kfree(deviceid);
 153         }
 154
 155         if (!detected && !last_try) {
 156                 /* No devices were detected.  Perhaps they are in some
 157                    funny state; let's try to reset them and see if
 158                    they wake up. */
 159                 parport_daisy_fini(port);
 160                 parport_write_control(port, PARPORT_CONTROL_SELECT);
 161                 udelay(50);
 162                 parport_write_control(port,
 163                                        PARPORT_CONTROL_SELECT |
 164                                        PARPORT_CONTROL_INIT);
 165                 udelay(50);
 166                 last_try = 1;
 167                 goto again;
 168         }
 169
 170         return detected;
 171 }
 172
 173 /* Forget about devices on a physical port. */
 174 void parport_daisy_fini(struct parport *port)
 175 {
 176         struct daisydev **p;
 177
 178         spin_lock(&topology_lock);
 179         p = &topology;
 180         while (*p) {
 181                 struct daisydev *dev = *p;
 182                 if (dev->port != port) {
 183                         p = &dev->next;
 184                         continue;
 185                 }
 186                 *p = dev->next;
 187                 kfree(dev);
 188         }
 189
 190         /* Gaps in the numbering could be handled better.  How should
 191            someone enumerate through all IEEE1284.3 devices in the
 192            topology?. */
 193         if (!topology) numdevs = 0;
 194         spin_unlock(&topology_lock);
 195         return;
 196 }
 197
 198 /**
 199  *      parport_open - find a device by canonical device number
 200  *      @devnum: canonical device number
 201  *      @name: name to associate with the device
 202  *      @pf: preemption callback
 203  *      @kf: kick callback
 204  *      @irqf: interrupt handler
 205  *      @flags: registration flags
 206  *      @handle: driver data
 207  *
 208  *      This function is similar to parport_register_device(), except
 209  *      that it locates a device by its number rather than by the port
 210  *      it is attached to.
 211  *
 212  *      All parameters except for @devnum are the same as for
 213  *      parport_register_device().  The return value is the same as
 214  *      for parport_register_device().
 215  **/
 216
 217 struct pardevice *parport_open(int devnum, const char *name,
 218                                 int (*pf) (void *), void (*kf) (void *),
 219                                 void (*irqf) (int, void *),
 220                                 int flags, void *handle)
 221 {
 222         struct daisydev *p = topology;
 223         struct parport *port;
 224         struct pardevice *dev;
 225         int daisy;
 226
 227         spin_lock(&topology_lock);
 228         while (p && p->devnum != devnum)
 229                 p = p->next;
 230
 231         if (!p) {
 232                 spin_unlock(&topology_lock);
 233                 return NULL;
 234         }
 235
 236         daisy = p->daisy;
 237         port = parport_get_port(p->port);
 238         spin_unlock(&topology_lock);
 239
 240         dev = parport_register_device(port, name, pf, kf,
 241                                        irqf, flags, handle);
 242         parport_put_port(port);
 243         if (!dev)
 244                 return NULL;
 245
 246         dev->daisy = daisy;
 247
 248         /* Check that there really is a device to select. */
 249         if (daisy >= 0) {
 250                 int selected;
 251                 parport_claim_or_block(dev);
 252                 selected = port->daisy;
 253                 parport_release(dev);
 254
 255                 if (selected != daisy) {
 256                         /* No corresponding device. */
 257                         parport_unregister_device(dev);
 258                         return NULL;
 259                 }
 260         }
 261
 262         return dev;
 263 }
 264
 265 /**
 266  *      parport_close - close a device opened with parport_open()
 267  *      @dev: device to close
 268  *
 269  *      This is to parport_open() as parport_unregister_device() is to
 270  *      parport_register_device().
 271  **/
 272
 273 void parport_close(struct pardevice *dev)
 274 {
 275         parport_unregister_device(dev);
 276 }
 277
 278 /**
 279  *      parport_device_num - convert device coordinates
 280  *      @parport: parallel port number
 281  *      @mux: multiplexor port number (-1 for no multiplexor)
 282  *      @daisy: daisy chain address (-1 for no daisy chain address)
 283  *
 284  *      This tries to locate a device on the given parallel port,
 285  *      multiplexor port and daisy chain address, and returns its
 286  *      device number or %-ENXIO if no device with those coordinates
 287  *      exists.
 288  **/
 289
 290 int parport_device_num(int parport, int mux, int daisy)
 291 {
 292         int res = -ENXIO;
 293         struct daisydev *dev;
 294
 295         spin_lock(&topology_lock);
 296         dev = topology;
 297         while (dev && dev->port->portnum != parport &&
 298                dev->port->muxport != mux && dev->daisy != daisy)
 299                 dev = dev->next;
 300         if (dev)
 301                 res = dev->devnum;
 302         spin_unlock(&topology_lock);
 303
 304         return res;
 305 }
 306
 307 /* Send a daisy-chain-style CPP command packet. */
 308 static int cpp_daisy(struct parport *port, int cmd)
 309 {
 310         unsigned char s;
 311
 312         parport_data_forward(port);
 313         parport_write_data(port, 0xaa); udelay(2);
 314         parport_write_data(port, 0x55); udelay(2);
 315         parport_write_data(port, 0x00); udelay(2);
 316         parport_write_data(port, 0xff); udelay(2);
 317         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 318                                           | PARPORT_STATUS_PAPEROUT
 319                                           | PARPORT_STATUS_SELECT
 320                                           | PARPORT_STATUS_ERROR);
 321         if (s != (PARPORT_STATUS_BUSY
 322                   | PARPORT_STATUS_PAPEROUT
 323                   | PARPORT_STATUS_SELECT
 324                   | PARPORT_STATUS_ERROR)) {
 325                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
 326                          port->name, s);
 327                 return -ENXIO;
 328         }
 329
 330         parport_write_data(port, 0x87); udelay(2);
 331         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 332                                           | PARPORT_STATUS_PAPEROUT
 333                                           | PARPORT_STATUS_SELECT
 334                                           | PARPORT_STATUS_ERROR);
 335         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 336                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
 337                          port->name, s);
 338                 return -ENXIO;
 339         }
 340
 341         parport_write_data(port, 0x78); udelay(2);
 342         parport_write_data(port, cmd); udelay(2);
 343         parport_frob_control(port,
 344                               PARPORT_CONTROL_STROBE,
 345                               PARPORT_CONTROL_STROBE);
 346         udelay(1);
 347         s = parport_read_status(port);
 348         parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 349         udelay(1);
 350         parport_write_data(port, 0xff); udelay(2);
 351
 352         return s;
 353 }
 354
 355 /* Send a mux-style CPP command packet. */
 356 static int cpp_mux(struct parport *port, int cmd)
 357 {
 358         unsigned char s;
 359         int rc;
 360
 361         parport_data_forward(port);
 362         parport_write_data(port, 0xaa); udelay(2);
 363         parport_write_data(port, 0x55); udelay(2);
 364         parport_write_data(port, 0xf0); udelay(2);
 365         parport_write_data(port, 0x0f); udelay(2);
 366         parport_write_data(port, 0x52); udelay(2);
 367         parport_write_data(port, 0xad); udelay(2);
 368         parport_write_data(port, cmd); udelay(2);
 369
 370         s = parport_read_status(port);
 371         if (!(s & PARPORT_STATUS_ACK)) {
 372                 DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
 373                          port->name, cmd, s);
 374                 return -EIO;
 375         }
 376
 377         rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
 378               ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
 379               ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
 380               ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
 381
 382         return rc;
 383 }
 384
 385 void parport_daisy_deselect_all(struct parport *port)
 386 {
 387         cpp_daisy(port, 0x30);
 388 }
 389
 390 int parport_daisy_select(struct parport *port, int daisy, int mode)
 391 {
 392         switch (mode)
 393         {
 394                 // For these modes we should switch to EPP mode:
 395                 case IEEE1284_MODE_EPP:
 396                 case IEEE1284_MODE_EPPSL:
 397                 case IEEE1284_MODE_EPPSWE:
 398                         return !(cpp_daisy(port, 0x20 + daisy) &
 399                                  PARPORT_STATUS_ERROR);
 400
 401                 // For these modes we should switch to ECP mode:
 402                 case IEEE1284_MODE_ECP:
 403                 case IEEE1284_MODE_ECPRLE:
 404                 case IEEE1284_MODE_ECPSWE:
 405                         return !(cpp_daisy(port, 0xd0 + daisy) &
 406                                  PARPORT_STATUS_ERROR);
 407
 408                 // Nothing was told for BECP in Daisy chain specification.
 409                 // May be it's wise to use ECP?
 410                 case IEEE1284_MODE_BECP:
 411                 // Others use compat mode
 412                 case IEEE1284_MODE_NIBBLE:
 413                 case IEEE1284_MODE_BYTE:
 414                 case IEEE1284_MODE_COMPAT:
 415                 default:
 416                         return !(cpp_daisy(port, 0xe0 + daisy) &
 417                                  PARPORT_STATUS_ERROR);
 418         }
 419 }
 420
 421 static int mux_present(struct parport *port)
 422 {
 423         return cpp_mux(port, 0x51) == 3;
 424 }
 425
 426 static int num_mux_ports(struct parport *port)
 427 {
 428         return cpp_mux(port, 0x58);
 429 }
 430
 431 static int select_port(struct parport *port)
 432 {
 433         int muxport = port->muxport;
 434         return cpp_mux(port, 0x60 + muxport) == muxport;
 435 }
 436
 437 static int assign_addrs(struct parport *port)
 438 {
 439         unsigned char s;
 440         unsigned char daisy;
 441         int thisdev = numdevs;
 442         int detected;
 443         char *deviceid;
 444
 445         parport_data_forward(port);
 446         parport_write_data(port, 0xaa); udelay(2);
 447         parport_write_data(port, 0x55); udelay(2);
 448         parport_write_data(port, 0x00); udelay(2);
 449         parport_write_data(port, 0xff); udelay(2);
 450         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 451                                           | PARPORT_STATUS_PAPEROUT
 452                                           | PARPORT_STATUS_SELECT
 453                                           | PARPORT_STATUS_ERROR);
 454         if (s != (PARPORT_STATUS_BUSY
 455                   | PARPORT_STATUS_PAPEROUT
 456                   | PARPORT_STATUS_SELECT
 457                   | PARPORT_STATUS_ERROR)) {
 458                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
 459                          port->name, s);
 460                 return 0;
 461         }
 462
 463         parport_write_data(port, 0x87); udelay(2);
 464         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 465                                           | PARPORT_STATUS_PAPEROUT
 466                                           | PARPORT_STATUS_SELECT
 467                                           | PARPORT_STATUS_ERROR);
 468         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 469                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
 470                          port->name, s);
 471                 return 0;
 472         }
 473
 474         parport_write_data(port, 0x78); udelay(2);
 475         s = parport_read_status(port);
 476
 477         for (daisy = 0;
 478              (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
 479                      == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
 480                      && daisy < 4;
 481              ++daisy) {
 482                 parport_write_data(port, daisy);
 483                 udelay(2);
 484                 parport_frob_control(port,
 485                                       PARPORT_CONTROL_STROBE,
 486                                       PARPORT_CONTROL_STROBE);
 487                 udelay(1);
 488                 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 489                 udelay(1);
 490
 491                 add_dev(numdevs++, port, daisy);
 492
 493                 /* See if this device thought it was the last in the
 494                  * chain. */
 495                 if (!(s & PARPORT_STATUS_BUSY))
 496                         break;
 497
 498                 /* We are seeing pass through status now. We see
 499                    last_dev from next device or if last_dev does not
 500                    work status lines from some non-daisy chain
 501                    device. */
 502                 s = parport_read_status(port);
 503         }
 504
 505         parport_write_data(port, 0xff); udelay(2);
 506         detected = numdevs - thisdev;
 507         DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
 508                  detected);
 509
 510         /* Ask the new devices to introduce themselves. */
 511         deviceid = kmalloc(1024, GFP_KERNEL);
 512         if (!deviceid) return 0;
 513
 514         for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
 515                 parport_device_id(thisdev, deviceid, 1024);
 516
 517         kfree(deviceid);
 518         return detected;
 519 }