olpt.c revision 183397
1/*- 2 * Copyright (c) 1990 William F. Jolitz, TeleMuse 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This software is a component of "386BSD" developed by 16 * William F. Jolitz, TeleMuse. 17 * 4. Neither the name of the developer nor the name "386BSD" 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ 22 * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS 23 * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. 24 * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT 25 * NOT MAKE USE OF THIS WORK. 26 * 27 * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED 28 * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN 29 * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES 30 * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING 31 * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND 32 * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE 33 * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS 34 * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992. 35 * 36 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND 37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 39 * ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE 40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 46 * SUCH DAMAGE. 47 * 48 * from: unknown origin, 386BSD 0.1 49 * $FreeBSD: head/sys/pc98/cbus/olpt.c 183397 2008-09-27 08:51:18Z ed $ 50 */ 51 52/* 53 * Device Driver for AT parallel printer port 54 * Written by William Jolitz 12/18/90 55 */ 56 57/* 58 * Parallel port TCP/IP interfaces added. I looked at the driver from 59 * MACH but this is a complete rewrite, and btw. incompatible, and it 60 * should perform better too. I have never run the MACH driver though. 61 * 62 * This driver sends two bytes (0x08, 0x00) in front of each packet, 63 * to allow us to distinguish another format later. 64 * 65 * Now added a Linux/Crynwr compatibility mode which is enabled using 66 * IF_LINK0 - Tim Wilkinson. 67 * 68 * TODO: 69 * Make HDLC/PPP mode, use IF_LLC1 to enable. 70 * 71 * Connect the two computers using a Laplink parallel cable to use this 72 * feature: 73 * 74 * +----------------------------------------+ 75 * |A-name A-End B-End Descr. Port/Bit | 76 * +----------------------------------------+ 77 * |DATA0 2 15 Data 0/0x01 | 78 * |-ERROR 15 2 1/0x08 | 79 * +----------------------------------------+ 80 * |DATA1 3 13 Data 0/0x02 | 81 * |+SLCT 13 3 1/0x10 | 82 * +----------------------------------------+ 83 * |DATA2 4 12 Data 0/0x04 | 84 * |+PE 12 4 1/0x20 | 85 * +----------------------------------------+ 86 * |DATA3 5 10 Strobe 0/0x08 | 87 * |-ACK 10 5 1/0x40 | 88 * +----------------------------------------+ 89 * |DATA4 6 11 Data 0/0x10 | 90 * |BUSY 11 6 1/~0x80 | 91 * +----------------------------------------+ 92 * |GND 18-25 18-25 GND - | 93 * +----------------------------------------+ 94 * 95 * Expect transfer-rates up to 75 kbyte/sec. 96 * 97 * If GCC could correctly grok 98 * register int port asm("edx") 99 * the code would be cleaner 100 * 101 * Poul-Henning Kamp <phk@freebsd.org> 102 */ 103 104#include <sys/param.h> 105#include <sys/systm.h> 106#include <sys/conf.h> 107#include <sys/bus.h> 108#include <sys/kernel.h> 109#include <sys/module.h> 110#include <sys/uio.h> 111#include <sys/syslog.h> 112#include <sys/malloc.h> 113 114#include <machine/bus.h> 115#include <machine/resource.h> 116#include <sys/rman.h> 117 118#include <isa/isavar.h> 119 120#include <pc98/cbus/olptreg.h> 121#include <dev/ppbus/lptio.h> 122 123#define LPINITRDY 4 /* wait up to 4 seconds for a ready */ 124#define LPTOUTINITIAL 10 /* initial timeout to wait for ready 1/10 s */ 125#define LPTOUTMAX 1 /* maximal timeout 1 s */ 126#define LPPRI (PZERO+8) 127#define BUFSIZE 1024 128 129#ifndef DEBUG 130#define lprintf(args) 131#else 132#define lprintf(args) do { \ 133 if (lptflag) \ 134 printf args; \ 135 } while (0) 136static int volatile lptflag = 1; 137#endif 138 139#define LPTUNIT(s) ((s)&0x03) 140#define LPTFLAGS(s) ((s)&0xfc) 141 142struct lpt_softc { 143 struct resource *res_port; 144 struct resource *res_irq; 145 void *sc_ih; 146 147 int sc_port; 148 short sc_state; 149 /* default case: negative prime, negative ack, handshake strobe, 150 prime once */ 151 u_char sc_control; 152 char sc_flags; 153#define LP_POS_INIT 0x04 /* if we are a postive init signal */ 154#define LP_POS_ACK 0x08 /* if we are a positive going ack */ 155#define LP_NO_PRIME 0x10 /* don't prime the printer at all */ 156#define LP_PRIMEOPEN 0x20 /* prime on every open */ 157#define LP_AUTOLF 0x40 /* tell printer to do an automatic lf */ 158#define LP_BYPASS 0x80 /* bypass printer ready checks */ 159 void *sc_inbuf; 160 short sc_xfercnt ; 161 char sc_primed; 162 char *sc_cp ; 163 u_char sc_irq ; /* IRQ status of port */ 164#define LP_HAS_IRQ 0x01 /* we have an irq available */ 165#define LP_USE_IRQ 0x02 /* we are using our irq */ 166#define LP_ENABLE_IRQ 0x04 /* enable IRQ on open */ 167 u_char sc_backoff ; /* time to call lptout() again */ 168}; 169 170/* bits for state */ 171#define OPEN (1<<0) /* device is open */ 172#define ASLP (1<<1) /* awaiting draining of printer */ 173#define ERROR (1<<2) /* error was received from printer */ 174#define OBUSY (1<<3) /* printer is busy doing output */ 175#define LPTOUT (1<<4) /* timeout while not selected */ 176#define TOUT (1<<5) /* timeout while not selected */ 177#define INIT (1<<6) /* waiting to initialize for open */ 178#define INTERRUPTED (1<<7) /* write call was interrupted */ 179 180 181/* status masks to interrogate printer status */ 182#define RDY_MASK (LPS_SEL|LPS_OUT|LPS_NBSY|LPS_NERR) /* ready ? */ 183#define LP_READY (LPS_SEL|LPS_NBSY|LPS_NERR) 184 185/* Printer Ready condition - from lpa.c */ 186/* Only used in polling code */ 187#define NOT_READY(x) ((inb(x) & LPS_NBSY) != LPS_NBSY) 188 189#define MAX_SLEEP (hz*5) /* Timeout while waiting for device ready */ 190#define MAX_SPIN 20 /* Max delay for device ready in usecs */ 191 192static timeout_t lptout; 193static int lpt_probe(device_t); 194static int lpt_attach(device_t); 195static void lpt_intr(void *); 196 197static devclass_t olpt_devclass; 198 199static device_method_t olpt_methods[] = { 200 DEVMETHOD(device_probe, lpt_probe), 201 DEVMETHOD(device_attach, lpt_attach), 202 { 0, 0 } 203}; 204 205static driver_t olpt_driver = { 206 "olpt", 207 olpt_methods, 208 sizeof (struct lpt_softc), 209}; 210 211DRIVER_MODULE(olpt, isa, olpt_driver, olpt_devclass, 0, 0); 212 213static d_open_t lptopen; 214static d_close_t lptclose; 215static d_write_t lptwrite; 216static d_ioctl_t lptioctl; 217 218static struct cdevsw lpt_cdevsw = { 219 .d_version = D_VERSION, 220 .d_flags = D_NEEDGIANT, 221 .d_open = lptopen, 222 .d_close = lptclose, 223 .d_write = lptwrite, 224 .d_ioctl = lptioctl, 225 .d_name = "lpt", 226}; 227 228static bus_addr_t lpt_iat[] = {0, 2, 4, 6}; 229 230/* 231 * New lpt port probe Geoff Rehmet - Rhodes University - 14/2/94 232 * Based partially on Rod Grimes' printer probe 233 * 234 * Logic: 235 * 1) If no port address was given, use the bios detected ports 236 * and autodetect what ports the printers are on. 237 * 2) Otherwise, probe the data port at the address given, 238 * using the method in Rod Grimes' port probe. 239 * (Much code ripped off directly from Rod's probe.) 240 * 241 * Comments from Rod's probe: 242 * Logic: 243 * 1) You should be able to write to and read back the same value 244 * to the data port. Do an alternating zeros, alternating ones, 245 * walking zero, and walking one test to check for stuck bits. 246 * 247 * 2) You should be able to write to and read back the same value 248 * to the control port lower 5 bits, the upper 3 bits are reserved 249 * per the IBM PC technical reference manauls and different boards 250 * do different things with them. Do an alternating zeros, alternating 251 * ones, walking zero, and walking one test to check for stuck bits. 252 * 253 * Some printers drag the strobe line down when the are powered off 254 * so this bit has been masked out of the control port test. 255 * 256 * XXX Some printers may not like a fast pulse on init or strobe, I 257 * don't know at this point, if that becomes a problem these bits 258 * should be turned off in the mask byte for the control port test. 259 * 260 * We are finally left with a mask of 0x14, due to some printers 261 * being adamant about holding other bits high ........ 262 * 263 * Before probing the control port, we write a 0 to the data port - 264 * If not, some printers chuck out garbage when the strobe line 265 * gets toggled. 266 * 267 * 3) Set the data and control ports to a value of 0 268 * 269 * This probe routine has been tested on Epson Lx-800, HP LJ3P, 270 * Epson FX-1170 and C.Itoh 8510RM 271 * printers. 272 * Quick exit on fail added. 273 */ 274 275int 276lpt_probe(device_t dev) 277{ 278#define PC98_OLD_LPT 0x40 279#define PC98_IEEE_1284_FUNCTION 0x149 280 int rid; 281 struct resource *res; 282 283 /* Check isapnp ids */ 284 if (isa_get_vendorid(dev)) 285 return ENXIO; 286 287 rid = 0; 288 res = isa_alloc_resourcev(dev, SYS_RES_IOPORT, &rid, lpt_iat, 4, 289 RF_ACTIVE); 290 if (res == NULL) 291 return ENXIO; 292 isa_load_resourcev(res, lpt_iat, 4); 293 294 if (isa_get_port(dev) == PC98_OLD_LPT) { 295 unsigned int pc98_ieee_mode, tmp; 296 297 tmp = inb(PC98_IEEE_1284_FUNCTION); 298 pc98_ieee_mode = tmp; 299 if ((tmp & 0x10) == 0x10) { 300 outb(PC98_IEEE_1284_FUNCTION, tmp & ~0x10); 301 tmp = inb(PC98_IEEE_1284_FUNCTION); 302 if ((tmp & 0x10) != 0x10) { 303 outb(PC98_IEEE_1284_FUNCTION, pc98_ieee_mode); 304 bus_release_resource(dev, SYS_RES_IOPORT, rid, 305 res); 306 return ENXIO; 307 } 308 } 309 } 310 311 bus_release_resource(dev, SYS_RES_IOPORT, rid, res); 312 return 0; 313} 314 315/* XXX Todo - try and detect if interrupt is working */ 316int 317lpt_attach(device_t dev) 318{ 319 int rid, unit; 320 struct lpt_softc *sc; 321 322 unit = device_get_unit(dev); 323 sc = device_get_softc(dev); 324 325 rid = 0; 326 sc->res_port = isa_alloc_resourcev(dev, SYS_RES_IOPORT, &rid, 327 lpt_iat, 4, RF_ACTIVE); 328 if (sc->res_port == NULL) 329 return ENXIO; 330 isa_load_resourcev(sc->res_port, lpt_iat, 4); 331 332 sc->sc_port = rman_get_start(sc->res_port); 333 sc->sc_primed = 0; /* not primed yet */ 334 335 outb(sc->sc_port+lpt_pstb_ctrl, LPC_DIS_PSTB); /* PSTB disable */ 336 outb(sc->sc_port+lpt_control, LPC_MODE8255); /* 8255 mode set */ 337 outb(sc->sc_port+lpt_control, LPC_NIRQ8); /* IRQ8 inactive */ 338 outb(sc->sc_port+lpt_control, LPC_NPSTB); /* PSTB inactive */ 339 outb(sc->sc_port+lpt_pstb_ctrl, LPC_EN_PSTB); /* PSTB enable */ 340 341 sc->sc_irq = 0; 342 if (isa_get_irq(dev) != -1) { 343 rid = 0; 344 sc->res_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, 345 RF_ACTIVE); 346 if (sc->res_irq == NULL) { 347 bus_release_resource(dev, SYS_RES_IOPORT, 0, 348 sc->res_port); 349 return ENXIO; 350 } 351 if (bus_setup_intr(dev, sc->res_irq, INTR_TYPE_TTY, NULL, lpt_intr, 352 sc, &sc->sc_ih)) { 353 bus_release_resource(dev, SYS_RES_IOPORT, 0, 354 sc->res_port); 355 bus_release_resource(dev, SYS_RES_IRQ, 0, 356 sc->res_irq); 357 return ENXIO; 358 } 359 sc->sc_irq = LP_HAS_IRQ | LP_USE_IRQ | LP_ENABLE_IRQ; 360 device_printf(dev, "Interrupt-driven port"); 361 } 362 363 /* XXX what to do about the flags in the minor number? */ 364 make_dev(&lpt_cdevsw, unit, UID_ROOT, GID_WHEEL, 0600, "lpt%d", unit); 365 make_dev(&lpt_cdevsw, unit | LP_BYPASS, 366 UID_ROOT, GID_WHEEL, 0600, "lpctl%d", unit); 367 368 return 0; 369} 370 371/* 372 * lptopen -- reset the printer, then wait until it's selected and not busy. 373 * If LP_BYPASS flag is selected, then we do not try to select the 374 * printer -- this is just used for passing ioctls. 375 */ 376 377static int 378lptopen (struct cdev *dev, int flags, int fmt, struct thread *td) 379{ 380 struct lpt_softc *sc; 381 int s; 382 int port; 383 384 sc = devclass_get_softc(olpt_devclass, LPTUNIT(dev2unit(dev))); 385 if (sc->sc_port == 0) 386 return (ENXIO); 387 388 if (sc->sc_state) { 389 lprintf(("lp: still open %x\n", sc->sc_state)); 390 return(EBUSY); 391 } else 392 sc->sc_state |= INIT; 393 394 sc->sc_flags = LPTFLAGS(dev2unit(dev)); 395 396 /* Check for open with BYPASS flag set. */ 397 if (sc->sc_flags & LP_BYPASS) { 398 sc->sc_state = OPEN; 399 return(0); 400 } 401 402 s = spltty(); 403 lprintf(("lp flags 0x%x\n", sc->sc_flags)); 404 port = sc->sc_port; 405 406 /* set IRQ status according to ENABLE_IRQ flag */ 407 if (sc->sc_irq & LP_ENABLE_IRQ) 408 sc->sc_irq |= LP_USE_IRQ; 409 else 410 sc->sc_irq &= ~LP_USE_IRQ; 411 412 /* init printer */ 413 sc->sc_state = OPEN; 414 sc->sc_inbuf = malloc(BUFSIZE, M_DEVBUF, M_WAITOK); 415 sc->sc_xfercnt = 0; 416 splx(s); 417 418 /* only use timeout if using interrupt */ 419 lprintf(("irq %x\n", sc->sc_irq)); 420 if (sc->sc_irq & LP_USE_IRQ) { 421 sc->sc_state |= TOUT; 422 timeout (lptout, (caddr_t)sc, 423 (sc->sc_backoff = hz/LPTOUTINITIAL)); 424 } 425 426 lprintf(("opened.\n")); 427 return(0); 428} 429 430static void 431lptout (void *arg) 432{ 433 struct lpt_softc *sc = arg; 434 int pl; 435 436 lprintf(("T %x ", inb(sc->sc_port+lpt_status))); 437 if (sc->sc_state & OPEN) { 438 sc->sc_backoff++; 439 if (sc->sc_backoff > hz/LPTOUTMAX) 440 sc->sc_backoff = sc->sc_backoff > hz/LPTOUTMAX; 441 timeout (lptout, (caddr_t)sc, sc->sc_backoff); 442 } else 443 sc->sc_state &= ~TOUT; 444 445 if (sc->sc_state & ERROR) 446 sc->sc_state &= ~ERROR; 447 448 /* 449 * Avoid possible hangs do to missed interrupts 450 */ 451 if (sc->sc_xfercnt) { 452 pl = spltty(); 453 lpt_intr(sc); 454 splx(pl); 455 } else { 456 sc->sc_state &= ~OBUSY; 457 wakeup(sc); 458 } 459} 460 461/* 462 * lptclose -- close the device, free the local line buffer. 463 * 464 * Check for interrupted write call added. 465 */ 466 467static int 468lptclose(struct cdev *dev, int flags, int fmt, struct thread *td) 469{ 470 struct lpt_softc *sc; 471 472 sc = devclass_get_softc(olpt_devclass, LPTUNIT(dev2unit(dev))); 473 if(sc->sc_flags & LP_BYPASS) 474 goto end_close; 475 476 sc->sc_state &= ~OPEN; 477 free(sc->sc_inbuf, M_DEVBUF); 478 479end_close: 480 sc->sc_state = 0; 481 sc->sc_xfercnt = 0; 482 lprintf(("closed.\n")); 483 return(0); 484} 485 486/* 487 * pushbytes() 488 * Workhorse for actually spinning and writing bytes to printer 489 * Derived from lpa.c 490 * Originally by ? 491 * 492 * This code is only used when we are polling the port 493 */ 494static int 495pushbytes(struct lpt_softc * sc) 496{ 497 int spin, err, tic; 498 char ch; 499 int port = sc->sc_port; 500 501 lprintf(("p")); 502 /* loop for every character .. */ 503 while (sc->sc_xfercnt > 0) { 504 /* printer data */ 505 ch = *(sc->sc_cp); 506 sc->sc_cp++; 507 sc->sc_xfercnt--; 508 509 /* 510 * Wait for printer ready. 511 * Loop 20 usecs testing BUSY bit, then sleep 512 * for exponentially increasing timeout. (vak) 513 */ 514 for (spin=0; NOT_READY(port+lpt_status) && spin<MAX_SPIN; ++spin) 515 DELAY(1); /* XXX delay is NOT this accurate! */ 516 if (spin >= MAX_SPIN) { 517 tic = 0; 518 while (NOT_READY(port+lpt_status)) { 519 /* 520 * Now sleep, every cycle a 521 * little longer .. 522 */ 523 tic = tic + tic + 1; 524 /* 525 * But no more than 10 seconds. (vak) 526 */ 527 if (tic > MAX_SLEEP) 528 tic = MAX_SLEEP; 529 err = tsleep(sc, LPPRI, 530 "lptpoll", tic); 531 if (err != EWOULDBLOCK) { 532 return (err); 533 } 534 } 535 } 536 537 /* output data */ 538 outb(port+lpt_data, ch); 539 DELAY(1); 540 outb(port+lpt_control, LPC_PSTB); 541 DELAY(1); 542 outb(port+lpt_control, LPC_NPSTB); 543 } 544 return(0); 545} 546 547/* 548 * lptwrite --copy a line from user space to a local buffer, then call 549 * putc to get the chars moved to the output queue. 550 * 551 * Flagging of interrupted write added. 552 */ 553 554static int 555lptwrite(struct cdev *dev, struct uio * uio, int ioflag) 556{ 557 register unsigned n; 558 int pl, err; 559 struct lpt_softc *sc; 560 561 sc = devclass_get_softc(olpt_devclass, LPTUNIT(dev2unit(dev))); 562 if(sc->sc_flags & LP_BYPASS) { 563 /* we can't do writes in bypass mode */ 564 return(EPERM); 565 } 566 567 sc->sc_state &= ~INTERRUPTED; 568 while ((n = min(BUFSIZE, uio->uio_resid)) != 0) { 569 sc->sc_cp = sc->sc_inbuf; 570 uiomove(sc->sc_cp, n, uio); 571 sc->sc_xfercnt = n ; 572 while ((sc->sc_xfercnt > 0)&&(sc->sc_irq & LP_USE_IRQ)) { 573 lprintf(("i")); 574 /* if the printer is ready for a char, */ 575 /* give it one */ 576 if ((sc->sc_state & OBUSY) == 0){ 577 lprintf(("\nC %d. ", sc->sc_xfercnt)); 578 pl = spltty(); 579 lpt_intr(sc); 580 (void) splx(pl); 581 } 582 lprintf(("W ")); 583 if (sc->sc_state & OBUSY) 584 if ((err = tsleep (sc, 585 LPPRI|PCATCH, "lpwrite", 0))) { 586 sc->sc_state |= INTERRUPTED; 587 return(err); 588 } 589 } 590 /* check to see if we must do a polled write */ 591 if(!(sc->sc_irq & LP_USE_IRQ) && (sc->sc_xfercnt)) { 592 lprintf(("p")); 593 if((err = pushbytes(sc))) 594 return(err); 595 } 596 } 597 return(0); 598} 599 600/* 601 * lptintr -- handle printer interrupts which occur when the printer is 602 * ready to accept another char. 603 * 604 * do checking for interrupted write call. 605 */ 606 607static void 608lpt_intr(void *arg) 609{ 610} 611 612static int 613lptioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags, struct thread *td) 614{ 615 int error = 0; 616 struct lpt_softc *sc; 617 u_int unit = LPTUNIT(dev2unit(dev)); 618 u_char old_sc_irq; /* old printer IRQ status */ 619 620 sc = devclass_get_softc(olpt_devclass, unit); 621 622 switch (cmd) { 623 case LPT_IRQ : 624 if(sc->sc_irq & LP_HAS_IRQ) { 625 /* 626 * NOTE: 627 * If the IRQ status is changed, 628 * this will only be visible on the 629 * next open. 630 * 631 * If interrupt status changes, 632 * this gets syslog'd. 633 */ 634 old_sc_irq = sc->sc_irq; 635 if(*(int*)data == 0) 636 sc->sc_irq &= (~LP_ENABLE_IRQ); 637 else 638 sc->sc_irq |= LP_ENABLE_IRQ; 639 if (old_sc_irq != sc->sc_irq ) 640 log(LOG_NOTICE, "lpt%c switched to %s mode\n", 641 (char)unit+'0', 642 (sc->sc_irq & LP_ENABLE_IRQ)? 643 "interrupt-driven":"polled"); 644 } else /* polled port */ 645 error = EOPNOTSUPP; 646 break; 647 default: 648 error = ENODEV; 649 } 650 651 return(error); 652} 653