/* * Copyright (c) 1990 William F. Jolitz, TeleMuse * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This software is a component of "386BSD" developed by * William F. Jolitz, TeleMuse. * 4. Neither the name of the developer nor the name "386BSD" * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ * AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS * SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT. * THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT * NOT MAKE USE OF THIS WORK. * * FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED * BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN * REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES * (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING * JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND * LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE * ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS * OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992. * * THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: unknown origin, 386BSD 0.1 * From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp * $Id: nlpt.c,v 1.8 1998/06/07 17:09:48 dfr Exp $ */ /* * Device Driver for AT parallel printer port * Written by William Jolitz 12/18/90 */ /* * Updated for ppbus by Nicolas Souchu * [Mon Jul 28 1997] */ #ifdef KERNEL #include "opt_devfs.h" #include #include #include #include #include #include #include #ifdef DEVFS #include #endif /*DEVFS*/ #include #include #include #endif /*KERNEL*/ #include #include #ifndef NLPT_DEBUG #define nlprintf (void) #else #define nlprintf if (nlptflag) printf static int volatile nlptflag = 1; #endif #define LPINITRDY 4 /* wait up to 4 seconds for a ready */ #define LPTOUTINITIAL 10 /* initial timeout to wait for ready 1/10 s */ #define LPTOUTMAX 1 /* maximal timeout 1 s */ #define LPPRI (PZERO+8) #define BUFSIZE 1024 #define LPTUNIT(s) ((s)&0x03) #define LPTFLAGS(s) ((s)&0xfc) static int nlpt = 0; #define MAXLPT 8 /* XXX not much better! */ static struct lpt_data *lptdata[MAXLPT]; #define LPT_NAME "nlpt" /* our official name */ static timeout_t nlptout; static int nlpt_port_test(struct lpt_data *sc, u_char data, u_char mask); static int nlpt_detect(struct lpt_data *sc); /* * Make ourselves visible as a ppbus driver */ static struct ppb_device *nlptprobe(struct ppb_data *ppb); static int nlptattach(struct ppb_device *dev); static void nlptintr(int unit); static void nlpt_drvinit(void *unused); #ifdef KERNEL static struct ppb_driver nlptdriver = { nlptprobe, nlptattach, LPT_NAME }; DATA_SET(ppbdriver_set, nlptdriver); #endif /* KERNEL */ /* bits for state */ #define OPEN (1<<0) /* device is open */ #define ASLP (1<<1) /* awaiting draining of printer */ #define EERROR (1<<2) /* error was received from printer */ #define OBUSY (1<<3) /* printer is busy doing output */ #define LPTOUT (1<<4) /* timeout while not selected */ #define TOUT (1<<5) /* timeout while not selected */ #define LPTINIT (1<<6) /* waiting to initialize for open */ #define INTERRUPTED (1<<7) /* write call was interrupted */ #define HAVEBUS (1<<8) /* the driver owns the bus */ /* status masks to interrogate printer status */ #define RDY_MASK (LPS_SEL|LPS_OUT|LPS_NBSY|LPS_NERR) /* ready ? */ #define LP_READY (LPS_SEL|LPS_NBSY|LPS_NERR) /* Printer Ready condition - from lpa.c */ /* Only used in polling code */ #define LPS_INVERT (LPS_NBSY | LPS_NACK | LPS_SEL | LPS_NERR) #define LPS_MASK (LPS_NBSY | LPS_NACK | LPS_OUT | LPS_SEL | LPS_NERR) #define NOT_READY(lpt) ((ppb_rstr(&(lpt)->lpt_dev)^LPS_INVERT)&LPS_MASK) #define MAX_SLEEP (hz*5) /* Timeout while waiting for device ready */ #define MAX_SPIN 20 /* Max delay for device ready in usecs */ static d_open_t nlptopen; static d_close_t nlptclose; static d_write_t nlptwrite; static d_ioctl_t nlptioctl; #define CDEV_MAJOR 16 static struct cdevsw nlpt_cdevsw = { nlptopen, nlptclose, noread, nlptwrite, /*16*/ nlptioctl, nullstop, nullreset, nodevtotty, /* lpt */ seltrue, nommap, nostrat, LPT_NAME, NULL, -1 }; static int lpt_request_ppbus(struct lpt_data *sc, int how) { int error; /* we have the bus only if the request succeded */ if ((error = ppb_request_bus(&sc->lpt_dev, how)) == 0) sc->sc_state |= HAVEBUS; return (error); } static int lpt_release_ppbus(struct lpt_data *sc) { int error; /* we do not have the bus only if the request succeded */ if ((error = ppb_release_bus(&sc->lpt_dev)) == 0) sc->sc_state &= ~HAVEBUS; return (error); } /* * Internal routine to nlptprobe to do port tests of one byte value */ static int nlpt_port_test(struct lpt_data *sc, u_char data, u_char mask) { int temp, timeout; data = data & mask; ppb_wdtr(&sc->lpt_dev, data); timeout = 10000; do { DELAY(10); temp = ppb_rdtr(&sc->lpt_dev) & mask; } while (temp != data && --timeout); nlprintf("out=%x\tin=%x\ttout=%d\n", data, temp, timeout); return (temp == data); } /* * New lpt port probe Geoff Rehmet - Rhodes University - 14/2/94 * Based partially on Rod Grimes' printer probe * * Logic: * 1) If no port address was given, use the bios detected ports * and autodetect what ports the printers are on. * 2) Otherwise, probe the data port at the address given, * using the method in Rod Grimes' port probe. * (Much code ripped off directly from Rod's probe.) * * Comments from Rod's probe: * Logic: * 1) You should be able to write to and read back the same value * to the data port. Do an alternating zeros, alternating ones, * walking zero, and walking one test to check for stuck bits. * * 2) You should be able to write to and read back the same value * to the control port lower 5 bits, the upper 3 bits are reserved * per the IBM PC technical reference manauls and different boards * do different things with them. Do an alternating zeros, alternating * ones, walking zero, and walking one test to check for stuck bits. * * Some printers drag the strobe line down when the are powered off * so this bit has been masked out of the control port test. * * XXX Some printers may not like a fast pulse on init or strobe, I * don't know at this point, if that becomes a problem these bits * should be turned off in the mask byte for the control port test. * * We are finally left with a mask of 0x14, due to some printers * being adamant about holding other bits high ........ * * Before probing the control port, we write a 0 to the data port - * If not, some printers chuck out garbage when the strobe line * gets toggled. * * 3) Set the data and control ports to a value of 0 * * This probe routine has been tested on Epson Lx-800, HP LJ3P, * Epson FX-1170 and C.Itoh 8510RM * printers. * Quick exit on fail added. */ static int nlpt_detect(struct lpt_data *sc) { int status; u_char data; u_char mask; int i, error; status = 1; /* assume success */ if ((error = lpt_request_ppbus(sc, PPB_DONTWAIT))) { printf(LPT_NAME ": cannot alloc ppbus (%d)!\n", error); status = 0 ; goto end_probe ; } mask = 0xff; data = 0x55; /* Alternating zeros */ if (!nlpt_port_test(sc, data, mask)) { status = 0 ; goto end_probe ; } data = 0xaa; /* Alternating ones */ if (!nlpt_port_test(sc, data, mask)) { status = 0 ; goto end_probe ; } for (i = 0; i < 8; i++) { /* Walking zero */ data = ~(1 << i); if (!nlpt_port_test(sc, data, mask)) { status = 0 ; goto end_probe ; } } for (i = 0; i < 8; i++) { /* Walking one */ data = (1 << i); if (!nlpt_port_test(sc, data, mask)) { status = 0 ; goto end_probe ; } } end_probe: /* write 0's to control and data ports */ ppb_wdtr(&sc->lpt_dev, 0); ppb_wctr(&sc->lpt_dev, 0); lpt_release_ppbus(sc); return (status); } /* * nlptprobe() */ static struct ppb_device * nlptprobe(struct ppb_data *ppb) { struct lpt_data *sc; sc = (struct lpt_data *) malloc(sizeof(struct lpt_data), M_TEMP, M_NOWAIT); if (!sc) { printf(LPT_NAME ": cannot malloc!\n"); return (0); } bzero(sc, sizeof(struct lpt_data)); lptdata[nlpt] = sc; /* * lpt dependent initialisation. */ sc->lpt_unit = nlpt; /* * ppbus dependent initialisation. */ sc->lpt_dev.id_unit = sc->lpt_unit; sc->lpt_dev.name = nlptdriver.name; sc->lpt_dev.ppb = ppb; sc->lpt_dev.intr = nlptintr; /* * Now, try to detect the printer. */ if (!nlpt_detect(sc)) { free(sc, M_TEMP); return (0); } /* Ok, go to next device on next probe */ nlpt ++; return (&sc->lpt_dev); } static int nlptattach(struct ppb_device *dev) { struct lpt_data *sc = lptdata[dev->id_unit]; int error; /* * Report ourselves */ printf(LPT_NAME "%d: on ppbus %d\n", dev->id_unit, dev->ppb->ppb_link->adapter_unit); sc->sc_primed = 0; /* not primed yet */ if ((error = lpt_request_ppbus(sc, PPB_DONTWAIT))) { printf(LPT_NAME ": cannot alloc ppbus (%d)!\n", error); return (0); } ppb_wctr(&sc->lpt_dev, LPC_NINIT); /* check if we can use interrupt, should be done by ppc stuff */ nlprintf("oldirq %x\n", sc->sc_irq); if (ppb_get_irq(&sc->lpt_dev)) { sc->sc_irq = LP_HAS_IRQ | LP_USE_IRQ | LP_ENABLE_IRQ; printf(LPT_NAME "%d: Interrupt-driven port\n", dev->id_unit); } else { sc->sc_irq = 0; nlprintf(LPT_NAME "%d: Polled port\n", dev->id_unit); } nlprintf("irq %x\n", sc->sc_irq); lpt_release_ppbus(sc); #ifdef DEVFS sc->devfs_token = devfs_add_devswf(&nlpt_cdevsw, dev->id_unit, DV_CHR, UID_ROOT, GID_WHEEL, 0600, LPT_NAME "%d", dev->id_unit); sc->devfs_token_ctl = devfs_add_devswf(&nlpt_cdevsw, dev->id_unit | LP_BYPASS, DV_CHR, UID_ROOT, GID_WHEEL, 0600, LPT_NAME "%d.ctl", dev->id_unit); #endif return (1); } static void nlptout(void *arg) { struct lpt_data *sc = arg; int pl; nlprintf ("T %x ", ppb_rstr(&sc->lpt_dev)); if (sc->sc_state & OPEN) { sc->sc_backoff++; if (sc->sc_backoff > hz/LPTOUTMAX) sc->sc_backoff = sc->sc_backoff > hz/LPTOUTMAX; timeout(nlptout, (caddr_t)sc, sc->sc_backoff); } else sc->sc_state &= ~TOUT; if (sc->sc_state & EERROR) sc->sc_state &= ~EERROR; /* * Avoid possible hangs do to missed interrupts */ if (sc->sc_xfercnt) { pl = spltty(); nlptintr(sc->lpt_unit); splx(pl); } else { sc->sc_state &= ~OBUSY; wakeup((caddr_t)sc); } } /* * nlptopen -- reset the printer, then wait until it's selected and not busy. * If LP_BYPASS flag is selected, then we do not try to select the * printer -- this is just used for passing ioctls. */ static int nlptopen(dev_t dev, int flags, int fmt, struct proc *p) { struct lpt_data *sc; int s; int trys; u_int unit = LPTUNIT(minor(dev)); if ((unit >= nlpt)) return (ENXIO); sc = lptdata[unit]; if (sc->sc_state) { nlprintf(LPT_NAME ": still open %x\n", sc->sc_state); return(EBUSY); } else sc->sc_state |= LPTINIT; sc->sc_flags = LPTFLAGS(minor(dev)); /* Check for open with BYPASS flag set. */ if (sc->sc_flags & LP_BYPASS) { sc->sc_state = OPEN; return(0); } /* request the ppbus only if we don't have it already */ if ((sc->sc_state & HAVEBUS) == 0 && lpt_request_ppbus(sc, PPB_WAIT|PPB_INTR)) return (EINTR); s = spltty(); nlprintf(LPT_NAME " flags 0x%x\n", sc->sc_flags); /* set IRQ status according to ENABLE_IRQ flag */ if (sc->sc_irq & LP_ENABLE_IRQ) sc->sc_irq |= LP_USE_IRQ; else sc->sc_irq &= ~LP_USE_IRQ; /* init printer */ if ((sc->sc_flags & LP_NO_PRIME) == 0) { if((sc->sc_flags & LP_PRIMEOPEN) || sc->sc_primed == 0) { ppb_wctr(&sc->lpt_dev, 0); sc->sc_primed++; DELAY(500); } } ppb_wctr(&sc->lpt_dev, LPC_SEL|LPC_NINIT); /* wait till ready (printer running diagnostics) */ trys = 0; do { /* ran out of waiting for the printer */ if (trys++ >= LPINITRDY*4) { splx(s); sc->sc_state = 0; nlprintf ("status %x\n", ppb_rstr(&sc->lpt_dev) ); lpt_release_ppbus(sc); return (EBUSY); } /* wait 1/4 second, give up if we get a signal */ if (tsleep((caddr_t)sc, LPPRI|PCATCH, "lptinit", hz/4) != EWOULDBLOCK) { sc->sc_state = 0; splx(s); lpt_release_ppbus(sc); return (EBUSY); } /* is printer online and ready for output */ } while ((ppb_rstr(&sc->lpt_dev) & (LPS_SEL|LPS_OUT|LPS_NBSY|LPS_NERR)) != (LPS_SEL|LPS_NBSY|LPS_NERR)); sc->sc_control = LPC_SEL|LPC_NINIT; if (sc->sc_flags & LP_AUTOLF) sc->sc_control |= LPC_AUTOL; /* enable interrupt if interrupt-driven */ if (sc->sc_irq & LP_USE_IRQ) sc->sc_control |= LPC_ENA; ppb_wctr(&sc->lpt_dev, sc->sc_control); sc->sc_state = OPEN; sc->sc_inbuf = geteblk(BUFSIZE); sc->sc_xfercnt = 0; splx(s); /* release the ppbus */ lpt_release_ppbus(sc); /* only use timeout if using interrupt */ nlprintf("irq %x\n", sc->sc_irq); if (sc->sc_irq & LP_USE_IRQ) { sc->sc_state |= TOUT; timeout(nlptout, (caddr_t)sc, (sc->sc_backoff = hz/LPTOUTINITIAL)); } nlprintf("opened.\n"); return(0); } /* * nlptclose -- close the device, free the local line buffer. * * Check for interrupted write call added. */ static int nlptclose(dev_t dev, int flags, int fmt, struct proc *p) { struct lpt_data *sc = lptdata[LPTUNIT(minor(dev))]; int err; if(sc->sc_flags & LP_BYPASS) goto end_close; if ((sc->sc_state & HAVEBUS) == 0 && (err = lpt_request_ppbus(sc, PPB_WAIT|PPB_INTR))) return (err); sc->sc_state &= ~OPEN; /* if the last write was interrupted, don't complete it */ if((!(sc->sc_state & INTERRUPTED)) && (sc->sc_irq & LP_USE_IRQ)) while ((ppb_rstr(&sc->lpt_dev) & (LPS_SEL|LPS_OUT|LPS_NBSY|LPS_NERR)) != (LPS_SEL|LPS_NBSY|LPS_NERR) || sc->sc_xfercnt) /* wait 1/4 second, give up if we get a signal */ if (tsleep((caddr_t)sc, LPPRI|PCATCH, "lpclose", hz) != EWOULDBLOCK) break; ppb_wctr(&sc->lpt_dev, LPC_NINIT); brelse(sc->sc_inbuf); end_close: /* release the bus anyway */ lpt_release_ppbus(sc); sc->sc_state = 0; sc->sc_xfercnt = 0; nlprintf("closed.\n"); return(0); } /* * nlpt_pushbytes() * Workhorse for actually spinning and writing bytes to printer * Derived from lpa.c * Originally by ? * * This code is only used when we are polling the port */ static int nlpt_pushbytes(struct lpt_data *sc) { int spin, err, tic; char ch; nlprintf("p"); /* loop for every character .. */ while (sc->sc_xfercnt > 0) { /* printer data */ ch = *(sc->sc_cp); sc->sc_cp++; sc->sc_xfercnt--; /* * Wait for printer ready. * Loop 20 usecs testing BUSY bit, then sleep * for exponentially increasing timeout. (vak) */ for (spin = 0; NOT_READY(sc) && spin < MAX_SPIN; ++spin) DELAY(1); /* XXX delay is NOT this accurate! */ if (spin >= MAX_SPIN) { tic = 0; while (NOT_READY(sc)) { /* * Now sleep, every cycle a * little longer .. */ tic = tic + tic + 1; /* * But no more than 10 seconds. (vak) */ if (tic > MAX_SLEEP) tic = MAX_SLEEP; err = tsleep((caddr_t)sc, LPPRI, LPT_NAME "poll", tic); if (err != EWOULDBLOCK) { return (err); } } } /* output data */ ppb_wdtr(&sc->lpt_dev, ch); /* strobe */ ppb_wctr(&sc->lpt_dev, sc->sc_control|LPC_STB); ppb_wctr(&sc->lpt_dev, sc->sc_control); } return(0); } /* * nlptwrite --copy a line from user space to a local buffer, then call * putc to get the chars moved to the output queue. * * Flagging of interrupted write added. */ static int nlptwrite(dev_t dev, struct uio *uio, int ioflag) { register unsigned n; int pl, err; struct lpt_data *sc = lptdata[LPTUNIT(minor(dev))]; if(sc->sc_flags & LP_BYPASS) { /* we can't do writes in bypass mode */ return(EPERM); } /* request the ppbus only if we don't have it already */ if ((sc->sc_state & HAVEBUS) == 0 && lpt_request_ppbus(sc, PPB_WAIT|PPB_INTR)) return (EINTR); sc->sc_state &= ~INTERRUPTED; while ((n = min(BUFSIZE, uio->uio_resid)) != 0) { sc->sc_cp = sc->sc_inbuf->b_data ; uiomove(sc->sc_cp, n, uio); sc->sc_xfercnt = n ; while ((sc->sc_xfercnt > 0)&&(sc->sc_irq & LP_USE_IRQ)) { nlprintf("i"); /* if the printer is ready for a char, */ /* give it one */ if ((sc->sc_state & OBUSY) == 0){ nlprintf("\nC %d. ", sc->sc_xfercnt); pl = spltty(); nlptintr(sc->lpt_unit); (void) splx(pl); } nlprintf("W "); if (sc->sc_state & OBUSY) if ((err = tsleep((caddr_t)sc, LPPRI|PCATCH, LPT_NAME "write", 0))) { sc->sc_state |= INTERRUPTED; return(err); } } /* check to see if we must do a polled write */ if(!(sc->sc_irq & LP_USE_IRQ) && (sc->sc_xfercnt)) { nlprintf("p"); err = nlpt_pushbytes(sc); if (err) return(err); } } /* we have not been interrupted, release the ppbus */ lpt_release_ppbus(sc); return(0); } /* * nlptintr -- handle printer interrupts which occur when the printer is * ready to accept another char. * * do checking for interrupted write call. */ static void nlptintr(int unit) { struct lpt_data *sc = lptdata[unit]; int sts; int i; /* we must own the bus to use it */ if ((sc->sc_state & HAVEBUS) == 0) return; /* * Is printer online and ready for output? * * Avoid falling back to nlptout() too quickly. First spin-loop * to see if the printer will become ready ``really soon now''. */ for (i = 0; i < 100 && ((sts=ppb_rstr(&sc->lpt_dev)) & RDY_MASK) != LP_READY; i++) ; if ((sts & RDY_MASK) == LP_READY) { sc->sc_state = (sc->sc_state | OBUSY) & ~EERROR; sc->sc_backoff = hz/LPTOUTINITIAL; if (sc->sc_xfercnt) { /* send char */ /*nlprintf("%x ", *sc->sc_cp); */ ppb_wdtr(&sc->lpt_dev, *sc->sc_cp++) ; ppb_wctr(&sc->lpt_dev, sc->sc_control|LPC_STB); /* DELAY(X) */ ppb_wctr(&sc->lpt_dev, sc->sc_control); /* any more data for printer */ if(--(sc->sc_xfercnt) > 0) return; } /* * No more data waiting for printer. * Wakeup is not done if write call was interrupted. */ sc->sc_state &= ~OBUSY; if(!(sc->sc_state & INTERRUPTED)) wakeup((caddr_t)sc); nlprintf("w "); return; } else { /* check for error */ if(((sts & (LPS_NERR | LPS_OUT) ) != LPS_NERR) && (sc->sc_state & OPEN)) sc->sc_state |= EERROR; /* nlptout() will jump in and try to restart. */ } nlprintf("sts %x ", sts); } static int nlptioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct proc *p) { int error = 0; struct lpt_data *sc; u_int unit = LPTUNIT(minor(dev)); u_char old_sc_irq; /* old printer IRQ status */ sc = lptdata[unit]; switch (cmd) { case LPT_IRQ : if(sc->sc_irq & LP_HAS_IRQ) { /* * NOTE: * If the IRQ status is changed, * this will only be visible on the * next open. * * If interrupt status changes, * this gets syslog'd. */ old_sc_irq = sc->sc_irq; if(*(int*)data == 0) sc->sc_irq &= (~LP_ENABLE_IRQ); else sc->sc_irq |= LP_ENABLE_IRQ; if (old_sc_irq != sc->sc_irq ) log(LOG_NOTICE, LPT_NAME "%d: switched to %s mode\n", unit, (sc->sc_irq & LP_ENABLE_IRQ)? "interrupt-driven":"polled"); } else /* polled port */ error = EOPNOTSUPP; break; default: error = ENODEV; } return(error); } static nlpt_devsw_installed = 0; static void nlpt_drvinit(void *unused) { dev_t dev; if( ! nlpt_devsw_installed ) { dev = makedev(CDEV_MAJOR, 0); cdevsw_add(&dev,&nlpt_cdevsw, NULL); nlpt_devsw_installed = 1; } } SYSINIT(nlptdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nlpt_drvinit,NULL)