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1/*2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code3 * 4 * Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>5 *6 * This program is free software; you can redistribute it and/or7 * modify it under the terms of the GNU General Public License8 * as published by the Free Software Foundation; either version9 * 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 under18 * the GNU Free Documentation License, Version 1.1 or any later version19 * 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 DEBUG32 33static struct daisydev {34 struct daisydev *next;35 struct parport *port;36 int daisy;37 int devnum;38} *topology = NULL;39static DEFINE_SPINLOCK(topology_lock);40 41static int numdevs;42static bool daisy_init_done;43 44/* Forward-declaration of lower-level functions. */45static int mux_present(struct parport *port);46static int num_mux_ports(struct parport *port);47static int select_port(struct parport *port);48static int assign_addrs(struct parport *port);49 50/* Add a device to the discovered topology. */51static 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). */69static 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 85static 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 97static struct parport_driver daisy_driver = {98 .name = "daisy_drv",99 .probe = daisy_drv_probe,100};101 102/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.103 * Return value is number of devices actually detected. */104int parport_daisy_init(struct parport *port)105{106 int detected = 0;107 char *deviceid;108 static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };109 int num_ports;110 int i;111 int last_try = 0;112 113 if (!daisy_init_done) {114 /*115 * flag should be marked true first as116 * parport_register_driver() might try to load the low117 * level driver which will lead to announcing new ports118 * and which will again come back here at119 * parport_daisy_init()120 */121 daisy_init_done = true;122 i = parport_register_driver(&daisy_driver);123 if (i) {124 pr_err("daisy registration failed\n");125 daisy_init_done = false;126 return i;127 }128 }129 130again:131 /* Because this is called before any other devices exist,132 * we don't have to claim exclusive access. */133 134 /* If mux present on normal port, need to create new135 * parports for each extra port. */136 if (port->muxport < 0 && mux_present(port) &&137 /* don't be fooled: a mux must have 2 or 4 ports. */138 ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {139 /* Leave original as port zero. */140 port->muxport = 0;141 pr_info("%s: 1st (default) port of %d-way multiplexor\n",142 port->name, num_ports);143 for (i = 1; i < num_ports; i++) {144 /* Clone the port. */145 struct parport *extra = clone_parport(port, i);146 if (!extra) {147 if (signal_pending(current))148 break;149 150 schedule();151 continue;152 }153 154 pr_info("%s: %d%s port of %d-way multiplexor on %s\n",155 extra->name, i + 1, th[i + 1], num_ports,156 port->name);157 158 /* Analyse that port too. We won't recurse159 forever because of the 'port->muxport < 0'160 test above. */161 parport_daisy_init(extra);162 }163 }164 165 if (port->muxport >= 0)166 select_port(port);167 168 parport_daisy_deselect_all(port);169 detected += assign_addrs(port);170 171 /* Count the potential legacy device at the end. */172 add_dev(numdevs++, port, -1);173 174 /* Find out the legacy device's IEEE 1284 device ID. */175 deviceid = kmalloc(1024, GFP_KERNEL);176 if (deviceid) {177 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)178 detected++;179 180 kfree(deviceid);181 }182 183 if (!detected && !last_try) {184 /* No devices were detected. Perhaps they are in some185 funny state; let's try to reset them and see if186 they wake up. */187 parport_daisy_fini(port);188 parport_write_control(port, PARPORT_CONTROL_SELECT);189 udelay(50);190 parport_write_control(port,191 PARPORT_CONTROL_SELECT |192 PARPORT_CONTROL_INIT);193 udelay(50);194 last_try = 1;195 goto again;196 }197 198 return detected;199}200 201/* Forget about devices on a physical port. */202void parport_daisy_fini(struct parport *port)203{204 struct daisydev **p;205 206 spin_lock(&topology_lock);207 p = &topology;208 while (*p) {209 struct daisydev *dev = *p;210 if (dev->port != port) {211 p = &dev->next;212 continue;213 }214 *p = dev->next;215 kfree(dev);216 }217 218 /* Gaps in the numbering could be handled better. How should219 someone enumerate through all IEEE1284.3 devices in the220 topology?. */221 if (!topology) numdevs = 0;222 spin_unlock(&topology_lock);223 return;224}225 226/**227 * parport_open - find a device by canonical device number228 * @devnum: canonical device number229 * @name: name to associate with the device230 *231 * This function is similar to parport_register_device(), except232 * that it locates a device by its number rather than by the port233 * it is attached to.234 *235 * All parameters except for @devnum are the same as for236 * parport_register_device(). The return value is the same as237 * for parport_register_device().238 **/239 240struct pardevice *parport_open(int devnum, const char *name)241{242 struct daisydev *p = topology;243 struct pardev_cb par_cb;244 struct parport *port;245 struct pardevice *dev;246 int daisy;247 248 memset(&par_cb, 0, sizeof(par_cb));249 spin_lock(&topology_lock);250 while (p && p->devnum != devnum)251 p = p->next;252 253 if (!p) {254 spin_unlock(&topology_lock);255 return NULL;256 }257 258 daisy = p->daisy;259 port = parport_get_port(p->port);260 spin_unlock(&topology_lock);261 262 dev = parport_register_dev_model(port, name, &par_cb, devnum);263 parport_put_port(port);264 if (!dev)265 return NULL;266 267 dev->daisy = daisy;268 269 /* Check that there really is a device to select. */270 if (daisy >= 0) {271 int selected;272 parport_claim_or_block(dev);273 selected = port->daisy;274 parport_release(dev);275 276 if (selected != daisy) {277 /* No corresponding device. */278 parport_unregister_device(dev);279 return NULL;280 }281 }282 283 return dev;284}285 286/**287 * parport_close - close a device opened with parport_open()288 * @dev: device to close289 *290 * This is to parport_open() as parport_unregister_device() is to291 * parport_register_device().292 **/293 294void parport_close(struct pardevice *dev)295{296 parport_unregister_device(dev);297}298 299/* Send a daisy-chain-style CPP command packet. */300static int cpp_daisy(struct parport *port, int cmd)301{302 unsigned char s;303 304 parport_data_forward(port);305 parport_write_data(port, 0xaa); udelay(2);306 parport_write_data(port, 0x55); udelay(2);307 parport_write_data(port, 0x00); udelay(2);308 parport_write_data(port, 0xff); udelay(2);309 s = parport_read_status(port) & (PARPORT_STATUS_BUSY310 | PARPORT_STATUS_PAPEROUT311 | PARPORT_STATUS_SELECT312 | PARPORT_STATUS_ERROR);313 if (s != (PARPORT_STATUS_BUSY314 | PARPORT_STATUS_PAPEROUT315 | PARPORT_STATUS_SELECT316 | PARPORT_STATUS_ERROR)) {317 pr_debug("%s: cpp_daisy: aa5500ff(%02x)\n", port->name, s);318 return -ENXIO;319 }320 321 parport_write_data(port, 0x87); udelay(2);322 s = parport_read_status(port) & (PARPORT_STATUS_BUSY323 | PARPORT_STATUS_PAPEROUT324 | PARPORT_STATUS_SELECT325 | PARPORT_STATUS_ERROR);326 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {327 pr_debug("%s: cpp_daisy: aa5500ff87(%02x)\n", port->name, s);328 return -ENXIO;329 }330 331 parport_write_data(port, 0x78); udelay(2);332 parport_write_data(port, cmd); udelay(2);333 parport_frob_control(port,334 PARPORT_CONTROL_STROBE,335 PARPORT_CONTROL_STROBE);336 udelay(1);337 s = parport_read_status(port);338 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);339 udelay(1);340 parport_write_data(port, 0xff); udelay(2);341 342 return s;343}344 345/* Send a mux-style CPP command packet. */346static int cpp_mux(struct parport *port, int cmd)347{348 unsigned char s;349 int rc;350 351 parport_data_forward(port);352 parport_write_data(port, 0xaa); udelay(2);353 parport_write_data(port, 0x55); udelay(2);354 parport_write_data(port, 0xf0); udelay(2);355 parport_write_data(port, 0x0f); udelay(2);356 parport_write_data(port, 0x52); udelay(2);357 parport_write_data(port, 0xad); udelay(2);358 parport_write_data(port, cmd); udelay(2);359 360 s = parport_read_status(port);361 if (!(s & PARPORT_STATUS_ACK)) {362 pr_debug("%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",363 port->name, cmd, s);364 return -EIO;365 }366 367 rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) |368 ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |369 ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) |370 ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3));371 372 return rc;373}374 375void parport_daisy_deselect_all(struct parport *port)376{377 cpp_daisy(port, 0x30);378}379 380int parport_daisy_select(struct parport *port, int daisy, int mode)381{382 switch (mode)383 {384 // For these modes we should switch to EPP mode:385 case IEEE1284_MODE_EPP:386 case IEEE1284_MODE_EPPSL:387 case IEEE1284_MODE_EPPSWE:388 return !(cpp_daisy(port, 0x20 + daisy) &389 PARPORT_STATUS_ERROR);390 391 // For these modes we should switch to ECP mode:392 case IEEE1284_MODE_ECP:393 case IEEE1284_MODE_ECPRLE:394 case IEEE1284_MODE_ECPSWE: 395 return !(cpp_daisy(port, 0xd0 + daisy) &396 PARPORT_STATUS_ERROR);397 398 // Nothing was told for BECP in Daisy chain specification.399 // May be it's wise to use ECP?400 case IEEE1284_MODE_BECP:401 // Others use compat mode402 case IEEE1284_MODE_NIBBLE:403 case IEEE1284_MODE_BYTE:404 case IEEE1284_MODE_COMPAT:405 default:406 return !(cpp_daisy(port, 0xe0 + daisy) &407 PARPORT_STATUS_ERROR);408 }409}410 411static int mux_present(struct parport *port)412{413 return cpp_mux(port, 0x51) == 3;414}415 416static int num_mux_ports(struct parport *port)417{418 return cpp_mux(port, 0x58);419}420 421static int select_port(struct parport *port)422{423 int muxport = port->muxport;424 return cpp_mux(port, 0x60 + muxport) == muxport;425}426 427static int assign_addrs(struct parport *port)428{429 unsigned char s;430 unsigned char daisy;431 int thisdev = numdevs;432 int detected;433 char *deviceid;434 435 parport_data_forward(port);436 parport_write_data(port, 0xaa); udelay(2);437 parport_write_data(port, 0x55); udelay(2);438 parport_write_data(port, 0x00); udelay(2);439 parport_write_data(port, 0xff); udelay(2);440 s = parport_read_status(port) & (PARPORT_STATUS_BUSY441 | PARPORT_STATUS_PAPEROUT442 | PARPORT_STATUS_SELECT443 | PARPORT_STATUS_ERROR);444 if (s != (PARPORT_STATUS_BUSY445 | PARPORT_STATUS_PAPEROUT446 | PARPORT_STATUS_SELECT447 | PARPORT_STATUS_ERROR)) {448 pr_debug("%s: assign_addrs: aa5500ff(%02x)\n", port->name, s);449 return 0;450 }451 452 parport_write_data(port, 0x87); udelay(2);453 s = parport_read_status(port) & (PARPORT_STATUS_BUSY454 | PARPORT_STATUS_PAPEROUT455 | PARPORT_STATUS_SELECT456 | PARPORT_STATUS_ERROR);457 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {458 pr_debug("%s: assign_addrs: aa5500ff87(%02x)\n", port->name, s);459 return 0;460 }461 462 parport_write_data(port, 0x78); udelay(2);463 s = parport_read_status(port);464 465 for (daisy = 0;466 (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))467 == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)468 && daisy < 4;469 ++daisy) {470 parport_write_data(port, daisy);471 udelay(2);472 parport_frob_control(port,473 PARPORT_CONTROL_STROBE,474 PARPORT_CONTROL_STROBE);475 udelay(1);476 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);477 udelay(1);478 479 add_dev(numdevs++, port, daisy);480 481 /* See if this device thought it was the last in the482 * chain. */483 if (!(s & PARPORT_STATUS_BUSY))484 break;485 486 /* We are seeing pass through status now. We see487 last_dev from next device or if last_dev does not488 work status lines from some non-daisy chain489 device. */490 s = parport_read_status(port);491 }492 493 parport_write_data(port, 0xff); udelay(2);494 detected = numdevs - thisdev;495 pr_debug("%s: Found %d daisy-chained devices\n", port->name, detected);496 497 /* Ask the new devices to introduce themselves. */498 deviceid = kmalloc(1024, GFP_KERNEL);499 if (!deviceid) return 0;500 501 for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)502 parport_device_id(thisdev, deviceid, 1024);503 504 kfree(deviceid);505 return detected;506}507