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FIRMWARE(9)	       FreeBSD Kernel Developer's Manual	   FIRMWARE(9)

     firmware_register,	firmware_unregister, firmware_get, firmware_put	--
     firmware image loading and	management

     #include <sys/param.h>
     #include <sys/systm.h>
     #include <sys/linker.h>
     #include <sys/firmware.h>

     struct firmware {
	     const char	     *name;	     /*	system-wide name */
	     const void	     *data;	     /*	location of image */
	     size_t	     datasize;	     /*	size of	image in bytes */
	     unsigned int    version;	     /*	version	of the image */
	     int	     refcnt;	     /*	held references	*/
	     struct firmware *parent;	     /*	not null if a subimage */
	     linker_file_t   file;	     /*	loadable module	*/

     struct firmware *
     firmware_register(const char *imagename, const void *data,
	 size_t	datasize, unsigned int version,	struct firmware	*parent);

     firmware_unregister(const char *imagename);

     struct firmware *
     firmware_get(const	char *imagename);

     firmware_put(struct firmware *fp, int flags);

     The firmware abstraction provides a convenient interface for loading
     firmware images into the kernel.  Specially crafted kernel	modules	are
     used to hold the firmware images.

     The function firmware_register() is used on load of such modules to reg-
     ister contained firmware images.  The arguments to	firmware_register()
     include a name that identifies the	image for later	requests to the
     firmware system, a	pointer	to the actual image, the size of the image and
     an	optional parent	image.	The parent image is used to keep track of ref-
     erences to	a given	module so that it can be unloaded on last reference.

     The function firmware_unregister()	removes	the firmware image identified
     by	the name from the system if there are no pending references or returns
     an	error otherwise.

     The function firmware_get() returns the requested firmware	image.	If the
     image is not yet registered with the system firmware_get()	tries to load
     a module with the corresponding name.  This involves the linker subsystem
     and disk access which is why firmware_get() must not be called with any
     locks (except for Giant).	On success firmware_get() returns a pointer to
     the image description and increases the reference count for this image.

     The function firmware_put() is used to drop the reference to a firmware
     image.  The flags argument	may be set to FIRMWARE_UNLOAD to indicate that
     the caller	wishes to unload the corresponding module if the image becomes



     The firmware system was introduced	in FreeBSD 6.1.

     This manual page was written by Max Laier <>.

FreeBSD	10.2			January	6, 2006			  FreeBSD 10.2


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