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