24.1 Probe and Attach

Information here about how the PCI bus code iterates through the unattached devices and see if a newly loaded kld will attach to any of them.

    /*
     * Simple KLD to play with the PCI functions.
     *
     * Murray Stokely
     */
    
    #define MIN(a,b) (((a) < (b)) ? (a) : (b))
    
    #include <sys/types.h>
    #include <sys/module.h>
    #include <sys/systm.h>  /* uprintf */ 
    #include <sys/errno.h>
    #include <sys/param.h>  /* defines used in kernel.h */
    #include <sys/kernel.h> /* types used in module initialization */
    #include <sys/conf.h>   /* cdevsw struct */
    #include <sys/uio.h>    /* uio struct */
    #include <sys/malloc.h>
    #include <sys/bus.h>  /* structs, prototypes for pci bus stuff */
    
    #include <pci/pcivar.h> /* For get_pci macros! */
    
    /* Function prototypes */
    d_open_t      mypci_open;
    d_close_t     mypci_close;
    d_read_t      mypci_read;
    d_write_t     mypci_write;
    
    /* Character device entry points */
    
    static struct cdevsw mypci_cdevsw = {
      mypci_open,
      mypci_close,
      mypci_read,
      mypci_write,
      noioctl,
      nopoll,
      nommap,
      nostrategy,
      "mypci",
      36,                   /* reserved for lkms - /usr/src/sys/conf/majors */
      nodump,
      nopsize,
      D_TTY,
      -1
    };
    
    /* vars */
    static dev_t sdev;
    
    /* We're more interested in probe/attach than with
       open/close/read/write at this point */
    
    int 
    mypci_open(dev_t dev, int oflags, int devtype, struct proc *p)
    {
      int err = 0;
    
      uprintf("Opened device \"mypci\" successfully.\n");
      return(err);
    }
    
    int 
    mypci_close(dev_t dev, int fflag, int devtype, struct proc *p)
    {
      int err=0;
    
      uprintf("Closing device \"mypci.\"\n"); 
      return(err);
    } 
    
    int
    mypci_read(dev_t dev, struct uio *uio, int ioflag)
    {
      int err = 0;
    
      uprintf("mypci read!\n");
      return err;
    }
    
    int
    mypci_write(dev_t dev, struct uio *uio, int ioflag)
    {
      int err = 0;
    
      uprintf("mypci write!\n");
      return(err);
    }
    
    /* PCI Support Functions */
    
    /*
     * Return identification string if this is device is ours.
     */
    static int
    mypci_probe(device_t dev)
    {
      uprintf("MyPCI Probe\n"
          "Vendor ID : 0x%x\n"
          "Device ID : 0x%x\n",pci_get_vendor(dev),pci_get_device(dev));
    
      if (pci_get_vendor(dev) == 0x11c1) {
        uprintf("We've got the Winmodem, probe successful!\n");
        return 0;
      }
    
      return ENXIO;
    }
    
    /* Attach function is only called if the probe is successful */
    
    static int
    mypci_attach(device_t dev)
    {
      uprintf("MyPCI Attach for : deviceID : 0x%x\n",pci_get_vendor(dev));
      sdev = make_dev(&mypci_cdevsw,
              0,
              UID_ROOT,
              GID_WHEEL,
              0600,
              "mypci");
      uprintf("Mypci device loaded.\n");
      return ENXIO;
    }
    
    /* Detach device. */
    
    static int
    mypci_detach(device_t dev)
    {
      uprintf("Mypci detach!\n");
      return 0;
    }
    
    /* Called during system shutdown after sync. */
    
    static int
    mypci_shutdown(device_t dev)
    {
      uprintf("Mypci shutdown!\n");
      return 0;
    }
    
    /*
     * Device suspend routine.  
     */
    static int
    mypci_suspend(device_t dev)
    {
      uprintf("Mypci suspend!\n");
      return 0;
    }
    
    /*
     * Device resume routine.
     */
    
    static int
    mypci_resume(device_t dev)
    {
      uprintf("Mypci resume!\n");
      return 0;
    }
    
    static device_method_t mypci_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,     mypci_probe),
        DEVMETHOD(device_attach,    mypci_attach),
        DEVMETHOD(device_detach,    mypci_detach),
        DEVMETHOD(device_shutdown,  mypci_shutdown),
        DEVMETHOD(device_suspend,   mypci_suspend),
        DEVMETHOD(device_resume,    mypci_resume),
    
        { 0, 0 }
    };
    
    static driver_t mypci_driver = {
        "mypci",
        mypci_methods,
        0,
        /*  sizeof(struct mypci_softc), */
    };
    
    static devclass_t mypci_devclass;
    
    DRIVER_MODULE(mypci, pci, mypci_driver, mypci_devclass, 0, 0);

Additional Resources

• PCI Special Interest Group

• PCI System Architecture, Fourth Edition by Tom Shanley, et al.