probe(9E)

NAME

     probe  -  determine  if  a  non-self-identifying  device  is
     present

SYNOPSIS

     #include <sys/conf.h>
     #include <sys/ddi.h>
     #include <sys/sunddi.h>

     static intprefixprobe(dev_info_t *dip);

INTERFACE LEVEL

     Solaris DDI specific (Solaris  DDI).  This  entry  point  is
     required  for  non-self-identifying devices.  You must write
     it  for  such   devices.   For   self-identifying   devices,
     nulldev(9F) should be specified in the dev_ops(9S) structure
     if a probe routine is not necessary.

ARGUMENTS

      dip  Pointer to the device's  dev_info structure.

DESCRIPTION

     probe() determines whether the device corresponding  to  dip
     actually  exists  and  is  a  valid  device for this driver.
     probe() is called after identify(9E) and  before  attach(9E)
     for  a  given  dip. For example, the probe() routine can map
     the device registers using ddi_map_regs(9F) then attempt  to
     access  the  hardware using ddi_peek(9F) or ddi_poke(9F) and
     determine if the device exists.  Then the  device  registers
     should be unmapped using ddi_unmap_regs(9F).

     To probe a device that was left powered off after  the  last
     detach(),  it  might be necessary to power it up. If so, the
     driver must power up the device by accessing  device  regis-
     ters  directly.  pm_raise_power(9F) will be not be available
     until attach(9E).  The framework ensures that the  ancestors
     of  the node being probed and all relevant platform-specific
     power management hardware is at full power at the time  that
     probe() is called.

     probe() should only probe the device. It should  not  change
     any software state and should not create any software state.
     Device initialization should be done in attach(9E).

     For a self-identifying  device,  this  entry  point  is  not
     necessary.   However,  if  a  device  exists  in  both self-
     identifying and non-self-identifying forms, a  probe()  rou-
     tine    can    be   provided   to   simplify   the   driver.
     ddi_dev_is_sid(9F) can then be  used  to  determine  whether
     probe()  needs to do any work. See ddi_dev_is_sid(9F) for an
     example.

RETURN VALUES

     DDI_PROBE_SUCCESS
           If the probe was successful.

     DDI_PROBE_FAILURE
           If the probe failed.

     DDI_PROBE_DONTCARE
           If the probe was unsuccessful, yet  attach(9E)  should
           still be called.

     DDI_PROBE_PARTIAL
           If the instance is not present now, but may be present
           in the future.

SEE ALSO

     attach(9E),        identify(9E),         ddi_dev_is_sid(9F),
     ddi_map_regs(9F),  ddi_peek(9F),  ddi_poke(9F), nulldev(9F),
     dev_ops(9S)

     Writing Device Drivers