lkm i/o port allocation problems

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Date: Fri, 18 Jun 2004 22:13:44 -0400
To: freebsd hackers <freebsd-hackers@freebsd.org>

/*I am trying to figure out how to port over an infrared reciever driver
from linux to freebsd. i have been reading the developers book, as well as the
source for sio/ep and several other char drivers that use i/o ports. i can't
seem to get my i/o port allocation to work. whenever i request the region w/
bus_alloc_resource() it returns NULL to me the first time i load my module.
however, once i try again, i get the message:

ser0 at port 0x2f8-0x2ff on isa0

ser is the name of my module. so it seems that even tho the alloc call is
failing, somehow i still have the region to myself??? and now, even after i
reboot my computer, whenever i try to load my module i immediately get the above
error message. so it seems that somehow, even tho it is restarted, it never
lets go of the i/o region?? this module is not called at start time, it is only
loaded when i give kldload command

my other problem is that in order to get the probe/attach functions to be
called, i used the identify function in which i call the BUS_ADD_CHILD()
function as i saw ep driver do. is this correct? b/c after i load my module
once, the next time i try to load it this call always fails. is this correct
way to do this? if not, how do i get the probe function to be called, b/c it
wasn't being called when i loaded my module. here is the code, it is very short
as i chopped out the extra stuff. if someone could please take a quick look im
sure it would be obvious what i've done wrong, but i can't see what the problem
is. i've been digging thru the resource allocation functions and they're just
to complex for me to understand atm. thanks very much for any help.
*/

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/param.h> /* defines used in kernel.h */
#include <sys/kernel.h> /* types used in module initialization */
#include <sys/module.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/bus.h>
#include <sys/conf.h> /* cdevsw struct */
#include <sys/malloc.h>
#include <sys/rman.h>
#include <sys/systm.h> /* uprintf */
#include <sys/uio.h> /* uio struct */

#include <isa/isavar.h>
#include <isa/pnpvar.h>

/* device structure */
static struct resource *rp;

char ser_driver_name[] = "ser";
devclass_t ser_devclass;

/* isa stuff */
static int ser_isa_attach(device_t);
static int ser_isa_detach(device_t);
static int ser_isa_probe(device_t);
static void ser_isa_ident(driver_t *, device_t);

static device_method_t ser_isa_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe, ser_isa_probe),
        DEVMETHOD(device_attach, ser_isa_attach),
        DEVMETHOD(device_detach, ser_isa_detach),
        DEVMETHOD(device_identify, ser_isa_ident),

        { 0, 0 }
};

static driver_t ser_isa_driver = {
        ser_driver_name,
        ser_isa_methods,
        0,
};

static struct isa_pnp_id ser_ids[] = {
        { 0, NULL}
};

static int ser_isa_probe(device_t dev)
{
    uprintf("probing\n");
        
    return 0;
}

static void ser_isa_ident(driver_t *driv, device_t dev)
{
    int ret = 0;
    device_t child;

    uprintf("identing\n");
    
    child = BUS_ADD_CHILD(dev, 0, "ser", 0);
    if(child == NULL){
        uprintf("bus add child == NULL\n");
        return;
    }

    device_set_driver(child, driv);

    /* allocate i/o ports */
    if( (ret = bus_set_resource(child, SYS_RES_IOPORT, 0, 0x2f8, 8)) )
        uprintf("bus set bad, ret = %d\n", ret);
        
}

static int ser_isa_attach(device_t dev)
{
    int rid;

    uprintf("attaching\n");

    rid = 0;
    rp = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 8, RF_ACTIVE);
    if(rp == NULL){
        uprintf("bus alloc bad\n");
    }else{
        uprintf("allocated bus resources\n");
    }
    
    return 0;
}

static int ser_isa_detach(device_t dev)
{
    /* give back i/o region */
    if(rp){
        if(bus_release_resource(dev, SYS_RES_IOPORT, 0, rp) == 0)
            uprintf("releasd resources\n");
        else
            uprintf("error releasein\n");
    }

    uprintf("detached\n");
    return 0;
}

/*
 * Load handler that deals with the loading and unloading of a KLD.
 */
static int
mdev_loader(struct module * m, int what, void *arg)
{
        int err = 0;

        switch (what) {
        case MOD_LOAD: /* kldload */
                break;
        case MOD_UNLOAD:
                break;
        default:
                err = EINVAL;
                break;
        }
        return (err);
}

DRIVER_MODULE(ser, isa, ser_isa_driver, ser_devclass, mdev_loader, 0);

-- 
-sean
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• Previous message: Les Biffle: "Re: quiet ATX mid-Towers"
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• Reply: M. Warner Losh: "Re: lkm i/o port allocation problems"
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