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  *
 203  *      This function is similar to parport_register_device(), except
 204  *      that it locates a device by its number rather than by the port
 205  *      it is attached to.
 206  *
 207  *      All parameters except for @devnum are the same as for
 208  *      parport_register_device().  The return value is the same as
 209  *      for parport_register_device().
 210  **/
 211
 212 struct pardevice *parport_open(int devnum, const char *name)
 213 {
 214         struct daisydev *p = topology;
 215         struct parport *port;
 216         struct pardevice *dev;
 217         int daisy;
 218
 219         spin_lock(&topology_lock);
 220         while (p && p->devnum != devnum)
 221                 p = p->next;
 222
 223         if (!p) {
 224                 spin_unlock(&topology_lock);
 225                 return NULL;
 226         }
 227
 228         daisy = p->daisy;
 229         port = parport_get_port(p->port);
 230         spin_unlock(&topology_lock);
 231
 232         dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
 233         parport_put_port(port);
 234         if (!dev)
 235                 return NULL;
 236
 237         dev->daisy = daisy;
 238
 239         /* Check that there really is a device to select. */
 240         if (daisy >= 0) {
 241                 int selected;
 242                 parport_claim_or_block(dev);
 243                 selected = port->daisy;
 244                 parport_release(dev);
 245
 246                 if (selected != daisy) {
 247                         /* No corresponding device. */
 248                         parport_unregister_device(dev);
 249                         return NULL;
 250                 }
 251         }
 252
 253         return dev;
 254 }
 255
 256 /**
 257  *      parport_close - close a device opened with parport_open()
 258  *      @dev: device to close
 259  *
 260  *      This is to parport_open() as parport_unregister_device() is to
 261  *      parport_register_device().
 262  **/
 263
 264 void parport_close(struct pardevice *dev)
 265 {
 266         parport_unregister_device(dev);
 267 }
 268
 269 /* Send a daisy-chain-style CPP command packet. */
 270 static int cpp_daisy(struct parport *port, int cmd)
 271 {
 272         unsigned char s;
 273
 274         parport_data_forward(port);
 275         parport_write_data(port, 0xaa); udelay(2);
 276         parport_write_data(port, 0x55); udelay(2);
 277         parport_write_data(port, 0x00); udelay(2);
 278         parport_write_data(port, 0xff); udelay(2);
 279         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 280                                           | PARPORT_STATUS_PAPEROUT
 281                                           | PARPORT_STATUS_SELECT
 282                                           | PARPORT_STATUS_ERROR);
 283         if (s != (PARPORT_STATUS_BUSY
 284                   | PARPORT_STATUS_PAPEROUT
 285                   | PARPORT_STATUS_SELECT
 286                   | PARPORT_STATUS_ERROR)) {
 287                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
 288                          port->name, s);
 289                 return -ENXIO;
 290         }
 291
 292         parport_write_data(port, 0x87); udelay(2);
 293         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 294                                           | PARPORT_STATUS_PAPEROUT
 295                                           | PARPORT_STATUS_SELECT
 296                                           | PARPORT_STATUS_ERROR);
 297         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 298                 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
 299                          port->name, s);
 300                 return -ENXIO;
 301         }
 302
 303         parport_write_data(port, 0x78); udelay(2);
 304         parport_write_data(port, cmd); udelay(2);
 305         parport_frob_control(port,
 306                               PARPORT_CONTROL_STROBE,
 307                               PARPORT_CONTROL_STROBE);
 308         udelay(1);
 309         s = parport_read_status(port);
 310         parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 311         udelay(1);
 312         parport_write_data(port, 0xff); udelay(2);
 313
 314         return s;
 315 }
 316
 317 /* Send a mux-style CPP command packet. */
 318 static int cpp_mux(struct parport *port, int cmd)
 319 {
 320         unsigned char s;
 321         int rc;
 322
 323         parport_data_forward(port);
 324         parport_write_data(port, 0xaa); udelay(2);
 325         parport_write_data(port, 0x55); udelay(2);
 326         parport_write_data(port, 0xf0); udelay(2);
 327         parport_write_data(port, 0x0f); udelay(2);
 328         parport_write_data(port, 0x52); udelay(2);
 329         parport_write_data(port, 0xad); udelay(2);
 330         parport_write_data(port, cmd); udelay(2);
 331
 332         s = parport_read_status(port);
 333         if (!(s & PARPORT_STATUS_ACK)) {
 334                 DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
 335                          port->name, cmd, s);
 336                 return -EIO;
 337         }
 338
 339         rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
 340               ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
 341               ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
 342               ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
 343
 344         return rc;
 345 }
 346
 347 void parport_daisy_deselect_all(struct parport *port)
 348 {
 349         cpp_daisy(port, 0x30);
 350 }
 351
 352 int parport_daisy_select(struct parport *port, int daisy, int mode)
 353 {
 354         switch (mode)
 355         {
 356                 // For these modes we should switch to EPP mode:
 357                 case IEEE1284_MODE_EPP:
 358                 case IEEE1284_MODE_EPPSL:
 359                 case IEEE1284_MODE_EPPSWE:
 360                         return !(cpp_daisy(port, 0x20 + daisy) &
 361                                  PARPORT_STATUS_ERROR);
 362
 363                 // For these modes we should switch to ECP mode:
 364                 case IEEE1284_MODE_ECP:
 365                 case IEEE1284_MODE_ECPRLE:
 366                 case IEEE1284_MODE_ECPSWE:
 367                         return !(cpp_daisy(port, 0xd0 + daisy) &
 368                                  PARPORT_STATUS_ERROR);
 369
 370                 // Nothing was told for BECP in Daisy chain specification.
 371                 // May be it's wise to use ECP?
 372                 case IEEE1284_MODE_BECP:
 373                 // Others use compat mode
 374                 case IEEE1284_MODE_NIBBLE:
 375                 case IEEE1284_MODE_BYTE:
 376                 case IEEE1284_MODE_COMPAT:
 377                 default:
 378                         return !(cpp_daisy(port, 0xe0 + daisy) &
 379                                  PARPORT_STATUS_ERROR);
 380         }
 381 }
 382
 383 static int mux_present(struct parport *port)
 384 {
 385         return cpp_mux(port, 0x51) == 3;
 386 }
 387
 388 static int num_mux_ports(struct parport *port)
 389 {
 390         return cpp_mux(port, 0x58);
 391 }
 392
 393 static int select_port(struct parport *port)
 394 {
 395         int muxport = port->muxport;
 396         return cpp_mux(port, 0x60 + muxport) == muxport;
 397 }
 398
 399 static int assign_addrs(struct parport *port)
 400 {
 401         unsigned char s;
 402         unsigned char daisy;
 403         int thisdev = numdevs;
 404         int detected;
 405         char *deviceid;
 406
 407         parport_data_forward(port);
 408         parport_write_data(port, 0xaa); udelay(2);
 409         parport_write_data(port, 0x55); udelay(2);
 410         parport_write_data(port, 0x00); udelay(2);
 411         parport_write_data(port, 0xff); udelay(2);
 412         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 413                                           | PARPORT_STATUS_PAPEROUT
 414                                           | PARPORT_STATUS_SELECT
 415                                           | PARPORT_STATUS_ERROR);
 416         if (s != (PARPORT_STATUS_BUSY
 417                   | PARPORT_STATUS_PAPEROUT
 418                   | PARPORT_STATUS_SELECT
 419                   | PARPORT_STATUS_ERROR)) {
 420                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
 421                          port->name, s);
 422                 return 0;
 423         }
 424
 425         parport_write_data(port, 0x87); udelay(2);
 426         s = parport_read_status(port) & (PARPORT_STATUS_BUSY
 427                                           | PARPORT_STATUS_PAPEROUT
 428                                           | PARPORT_STATUS_SELECT
 429                                           | PARPORT_STATUS_ERROR);
 430         if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
 431                 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
 432                          port->name, s);
 433                 return 0;
 434         }
 435
 436         parport_write_data(port, 0x78); udelay(2);
 437         s = parport_read_status(port);
 438
 439         for (daisy = 0;
 440              (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
 441                      == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
 442                      && daisy < 4;
 443              ++daisy) {
 444                 parport_write_data(port, daisy);
 445                 udelay(2);
 446                 parport_frob_control(port,
 447                                       PARPORT_CONTROL_STROBE,
 448                                       PARPORT_CONTROL_STROBE);
 449                 udelay(1);
 450                 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
 451                 udelay(1);
 452
 453                 add_dev(numdevs++, port, daisy);
 454
 455                 /* See if this device thought it was the last in the
 456                  * chain. */
 457                 if (!(s & PARPORT_STATUS_BUSY))
 458                         break;
 459
 460                 /* We are seeing pass through status now. We see
 461                    last_dev from next device or if last_dev does not
 462                    work status lines from some non-daisy chain
 463                    device. */
 464                 s = parport_read_status(port);
 465         }
 466
 467         parport_write_data(port, 0xff); udelay(2);
 468         detected = numdevs - thisdev;
 469         DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
 470                  detected);
 471
 472         /* Ask the new devices to introduce themselves. */
 473         deviceid = kmalloc(1024, GFP_KERNEL);
 474         if (!deviceid) return 0;
 475
 476         for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
 477                 parport_device_id(thisdev, deviceid, 1024);
 478
 479         kfree(deviceid);
 480         return detected;
 481 }