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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!uunet!in3.uu.net!207.76.204.12!news.whistle.com!usenet From: Julian Elischer <julian@whistle.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: writting device drivers.. Date: Sat, 01 Feb 1997 22:58:26 -0800 Organization: Whistle Communications Lines: 445 Message-ID: <32F43B12.52BFA1D7@whistle.com> References: <5cjbuv$6bp@epsilon.qmw.ac.uk> NNTP-Posting-Host: s205m22.whistle.com Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------695678E263DECDAD62319AC4" X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386) Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:34882 This is a multi-part message in MIME format. --------------695678E263DECDAD62319AC4 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit eng-jon Ong wrote: > > Hi there.. > Can anyone tell me if writting device drivers for the > FreeBSD kernel is more or less similar to writting device > drivers for Linux? Is there any major differences or lots > of minor things here and there? Is there any document or somesort > of HOWTO to point out or get a person started for writting > device drivers and installing interrupt handlers for freeBSD? > > Thanks in advance.. > > ongej here is a script that makes a skeleton device driver for freeBSD 2.2. run it as sh make_device_driver.sh foo to ad a foo driver to the kernel and then edit it to do what you want.. I have a differnt script for pseudo device drivers (ones that dont have specific hardware (e.g /dev/null) let me know if you want a copy of that... julian --------------695678E263DECDAD62319AC4 Content-Type: text/plain; charset=us-ascii; name="make_device_driver.sh" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="make_device_driver.sh" #!/bin/sh # This writes a skeleton driver and puts it into the kernel tree for you #arg1 is lowercase "foo" # # Trust me, RUN THIS SCRIPT :) # #-------cut here------------------ cd /sys/i386/conf if [ "${1}X" = "X" ] then echo "Hey , how about some help here.. give me a device name!" exit 1 fi UPPER=`echo ${1} |tr "[:lower:]" "[:upper:]"` cat >files.${UPPER} <<DONE i386/isa/${1}.c optional ${1} device-driver DONE cat >${UPPER} <<DONE # Configuration file for kernel type: ${UPPER} ident ${UPPER} # \$Id:\$" DONE grep -v GENERIC < GENERIC >>${UPPER} cat >>${UPPER} <<DONE # trust me, you'll need this options DDB device ${1}0 at isa? port 0x234 bio irq 5 vector ${1}intr DONE cat >../isa/${1}.c <<DONE /* * Copyright ME * * ${1} driver * \$Id:\$ */ #include "${1}.h" /* generated file.. defines N${UPPER} */ #include <sys/param.h> #include <sys/systm.h> #include <sys/kernel.h> /* SYSINIT stuff */ #include <sys/conf.h> /* cdevsw stuff */ #include <sys/malloc.h> /* malloc region definitions */ #include <machine/clock.h> /* DELAY() */ #include <i386/isa/isa.h> /* ISA bus port definitions etc. */ #include <i386/isa/isa_device.h>/* ISA bus configuration structures */ #include <sys/${1}io.h> /* ${1} IOCTL definitions */ #ifdef DEVFS #include <sys/devfsext.h> /* DEVFS defintitions */ #endif /* DEVFS */ /* Function prototypes (these should all be static except for ${1}intr()) */ static d_open_t ${1}open; static d_close_t ${1}close; static d_read_t ${1}read; static d_write_t ${1}write; static d_ioctl_t ${1}ioctl; static d_mmap_t ${1}mmap; static d_select_t ${1}select; static int ${1}probe (struct isa_device *); static int ${1}attach (struct isa_device *); /* void ${1}intr(int unit);*//* actually defined in ioconf.h (generated file) */ #define CDEV_MAJOR 20 static struct cdevsw ${1}_cdevsw = { ${1}open, ${1}close, ${1}read, ${1}write, ${1}ioctl, nullstop, nullreset, nodevtotty, ${1}select, ${1}mmap, NULL, "${1}", NULL, -1 }; struct isa_driver ${1}driver = { ${1}probe, ${1}attach, "${1}" }; /* * device specific Misc defines */ #define BUFFERSIZE 1024 #define NUMPORTS 4 #define UNIT(dev) minor(dev) /* assume one minor number per unit */ /* * One of these per allocated device */ struct ${1}_softc { struct isa_device *dev; char buffer[BUFFERSIZE]; #ifdef DEVFS static void *devfs_token; #endif } ; typedef struct ${1}_softc *sc_p; static sc_p sca[N${UPPER}]; /* add your own test to see if it exists */ /* should return the number of ports needed */ static int ${1}probe (struct isa_device *dev) { char val; int unit = dev->id_unit; sc_p scp = sca[unit]; /* * Check the unit makes sense. */ if (unit > N${UPPER}) { printf("bad unit (%d)\n", unit); return (0); } if (scp) { printf("unit $d already attached\n", unit); return (0); } /* * try see if the device is there. */ val = inb (dev->id_iobase); if ( val != 42 ) { return (0); } /* * ok, we got one we think * do some further (this time possibly destructive) tests. */ outb (dev->id_iobase, 0xff); DELAY (10000); /* 10 ms delay */ val = inb (dev->id_iobase) & 0x0f; return ((val & 0x0f) == 0x0f)? NUMPORTS : 0 ; } /* * Called if the probe succeeded. * We can be destructive here as we know we have the device. * we can also trust the unit number. */ static int ${1}attach (struct isa_device *dev) { int unit = dev->id_unit; sc_p scp = sca[unit]; /* * Allocate storage for this instance . */ scp = malloc(sizeof(*scp), M_DEVBUF, M_NOWAIT); if( scp == NULL) { printf("${1}%d failed to allocage driver strorage\n", unit); return (0); } bzero(scp, sizeof(*scp)); sca[unit] = scp; /* * Store whatever seems wise. */ scp->dev = dev; #if DEVFS scp->devfs_token = devfs_add_devswf(&${1}_cdevsw, unit, DV_CHR, UID_ROOT, GID_KMEM, 0600, "${1}%d", unit); #endif return 1; } /* * Macro to check that the unit number is valid * Often this isn't needed as once the open() is performed, * the unit number is pretty much safe.. The exception would be if we * implemented devices that could "go away". in which case all these routines * would be wise to check the number, DIAGNOSTIC or not. */ #define CHECKUNIT(RETVAL) \ do { /* the do-while is a safe way to do this grouping */ \ if (unit > N${UPPER}) { \ printf(__FUNCTION__ ":bad unit $d\n", unit); \ return (RETVAL); \ } \ if (scp == NULL) { \ printf( __FUNCTION__ ": unit $d not attached\n", unit);\ return (RETVAL); \ } \ } while (0) #ifdef DIAGNOSTIC #define CHECKUNIT_DIAG(RETVAL) CHECKUNIT(RETVAL) #else /* DIAGNOSTIC */ #define CHECKUNIT_DIAG(RETVAL) #endif /* DIAGNOSTIC */ void ${1}intr(int unit) { sc_p scp = sca[unit]; /* * well we got an interupt, now what? * Theoretically we don't need to check the unit. */ return; } int ${1}ioctl (dev_t dev, int cmd, caddr_t data, int flag, struct proc *p) { int unit = UNIT (dev); sc_p scp = sca[unit]; CHECKUNIT_DIAG(ENXIO); switch (cmd) { case DHIOCRESET: /* whatever resets it */ outb(scp->dev->id_iobase, 0xff); break; default: return ENXIO; } return (0); } /* * You also need read, write, open, close routines. * This should get you started */ static int ${1}open(dev_t dev, int oflags, int devtype, struct proc *p) { int unit = UNIT (dev); sc_p scp = sca[unit]; CHECKUNIT(ENXIO); /* * Do processing */ return (0); } static int ${1}close(dev_t dev, int fflag, int devtype, struct proc *p) { int unit = UNIT (dev); sc_p scp = sca[unit]; CHECKUNIT_DIAG(ENXIO); /* * Do processing */ return (0); } static int ${1}read(dev_t dev, struct uio *uio, int ioflag) { int unit = UNIT (dev); sc_p scp = sca[unit]; int toread; CHECKUNIT_DIAG(ENXIO); /* * Do processing * read from buffer */ toread = (min(uio->uio_resid, sizeof(scp->buffer))); return(uiomove(scp->buffer, toread, uio)); } static int ${1}write(dev_t dev, struct uio *uio, int ioflag) { int unit = UNIT (dev); sc_p scp = sca[unit]; int towrite; CHECKUNIT_DIAG(ENXIO); /* * Do processing * write to buffer */ towrite = (min(uio->uio_resid, sizeof(scp->buffer))); return(uiomove(scp->buffer, towrite, uio)); } static int ${1}mmap(dev_t dev, int offset, int nprot) { int unit = UNIT (dev); sc_p scp = sca[unit]; CHECKUNIT_DIAG(-1); /* * Do processing */ #if 0 /* if we had a frame buffer or whatever.. do this */ if (offset > FRAMEBUFFERSIZE - PAGE_SIZE) { return (-1); } return i386_btop((FRAMEBASE + offset)); #else return (-1); #endif } static int ${1}select(dev_t dev, int which, struct proc *p) { int unit = UNIT (dev); sc_p scp = sca[unit]; CHECKUNIT_DIAG(ENXIO); /* * Do processing */ return (0); /* this is the wrong value I'm sure */ } /* * Now for some driver initialisation. * Occurs ONCE during boot (very early). */ static void ${1}_drvinit(void *unused) { dev_t dev; dev = makedev(CDEV_MAJOR, 0); cdevsw_add(&dev, &${1}_cdevsw, NULL); } SYSINIT(${1}dev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE+CDEV_MAJOR, ${1}_drvinit, NULL) DONE cat >../../sys/${1}io.h <<DONE /* * Definitions needed to access the ${1} device (ioctls etc) * see mtio.h , ioctl.h as examples */ #ifndef SYS_DHIO_H #define SYS_DHIO_H #ifndef KERNEL #include <sys/types.h> #endif #include <sys/ioccom.h> /* * define an ioctl here */ #define DHIOCRESET _IO('D', 0) /* reset the ${1} device */ #endif DONE config ${UPPER} cd ../../compile/${UPPER} make depend make ${1}.o make exit #--------------end of script--------------- # #you also need to add an entry into the cdevsw[] #array in conf.c, but it's too hard to do in a script.. # #edit to your taste.. # # --------------695678E263DECDAD62319AC4--