ddi_fm_handler_register(9F)				   Kernel Functions for Drivers 			       ddi_fm_handler_register(9F)

NAME

       ddi_fm_handler_register, ddi_fm_handler_unregister - register or unregister an error handling callback

SYNOPSIS

       #include <sys/ddifm.h>

       void ddi_fm_handler_register(dev_info_t *dip,
	    ddi_err_func_t error_handler, void *impl_data);

       void ddi_fm_handler_unregister(dev_info_t *dip);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI)

PARAMETERS

       dip		Pointer to the dev_info structure

       error_handler	Pointer to an error handler callback function

       impl_data	Pointer to private data for use by the caller

DESCRIPTION

       The  ddi_fm_handler_register() function registers an error handler callback routine with the I/O Fault Management framework. The error han-
       dler callback, error_handler, is called to process error conditions detected by the system. In addition to its device  instance,  dip,  the
       error handler is called with a pointer to a fault management error status structure, ddi_fm_error_t. For example:

	 int (*ddi_err_func_t)(dev_info_t *dip, ddi_fm_error_t *error_status);

       A driver error handling callback is passed the following arguments:

	   o	  a pointer to the device instance registered for this callback.

	   o	  a data structure containing common fault management data and status for error handling.

       The primary responsibilities of the error handler include:

	   o	  to check for outstanding hardware or software errors.

	   o	  where possible, to isolate the device that might have caused the errors.

	   o	  to report errors that were detected.

       During the invocation of an error handler, a device driver  might need to quiesce or suspend all I/O activities in order to check for error
       conditions or status in:

	   o	  hardware control and status registers.

	   o	  outstanding I/O transactions.

	   o	  access or DMA handles.

       For each error detected, the driver must formulate and post an error report via ddi_fm_ereport_post() for problem analysis by  the  Solaris
       Fault Manager fmd(1M).

       For a PCI, PCI/X, or PCI Express leaf device, the pci_ereport_post() function is provided to carry out reporting responsibilities on behalf
       of the driver. In many cases, an error handler callback function of the following form can be used:

	 xxx_err_cb(dev_info_t *dip, ddi_fm_error_t *errp) {
	       pci_ereport_post(dip, errp, NULL);
	       return (errp->fme_status);
	 }

       In addition, the driver might be able to carry out further device specific checks within the error handler.

       Error handlers can be called  from  kernel,  interrupt,	or  high-level	interrupt  context.  The  interrupt  block  cookie  returned  from
       ddi_fm_init() should be used to allocate and initialize any synchronization variables and locks that might be used within the error handler
       callback function. Such locks may not be held by the driver when a device register is accessed with  functions  such  as  ddi_get8(9F)  and
       ddi_put8(9F).

       The  data  structure,  ddi_fm_error_t,  contains  an FMA protocol (format 1) ENA for the current error propagation chain, the status of the
       error handler callback, an error expectation flag, and any potential access or DMA handles associated with an error detected by the  parent
       nexus.

       The  ddi_fm_handler_unregister()  function removes a previously registered error handling callback for the device instance specified by the
       dip.

CONTEXT

       The ddi_fm_handler_register() and ddi_fm_handler_unregister() functions must be called from kernel context in an attach(9E)  or	detach(9E)
       entry point. The registered error handler, error_handler, callback can be called from kernel, interrupt, or high level interrupt context.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

       fmd(1M), attributes(5), attach(9E), detach(9E), ddi_fm_ereport_post(9F), ddi_fm_init(9F), ddi_get8(9F), ddi_put8(9F), pci_ereport_post(9F),
       ddi_fm_error(9S)

       Writing Device Drivers

SunOS 5.11							    14 May 2007 				       ddi_fm_handler_register(9F)