firmware_close(9) [netbsd man page]

FIRMLOAD(9)						   BSD Kernel Developer's Manual					       FIRMLOAD(9)

NAME

     firmload -- Firmware loader API for device drivers

SYNOPSIS

     #include <dev/firmload.h>

     int
     firmware_open(const char *drvname, const char *imgname, firmware_handle_t *fhp);

     int
     firmware_close(firmware_handle_t fh);

     off_t
     firmware_get_size(firmware_handle_t fh);

     int
     firmware_read(firmware_handle_t fh, off_t offset, void *buf, size_t size);

     void *
     firmware_malloc(size_t size);

     void
     firmware_free(void *buf, size_t size);

DESCRIPTION

     firmload provides a simple and convenient API for device drivers to load firmware images from files residing in the file system that are nec-
     essary for the devices that they control.	Firmware images reside in sub-directories, one for each driver, of a series of colon-separated
     path prefixes specified by the sysctl variable hw.firmware.path.

FUNCTIONS

     The following functions are provided by the firmload API:

     firmware_open(drvname, imgname, fhp)

	     Open then firmware image imgname for the driver drvname.  The path to the firmware image file is constructed by appending the string
	     ``/drvname/imgname'' to each configured path prefix until opening the firmware image file succeeds.  Upon success, firmware_open()
	     returns 0 and stores a firmware image handle in the location pointed to by fhp.  Otherwise, an error code is returned to indicate the
	     reason for failure.

     firmware_close(fh)

	     Close the firmware image file associated with the firmware handle fh.  Returns 0 upon success or an error code to indicate the reason
	     for failure.

     firmware_get_size(fh)

	     Returns the size of the image file associated with the firmware handle fh.

     firmware_read(fh, offset, buf, size)

	     Reads from the image file associated with the firmware handle fh beginning at offset offset for length size.  The firmware image data
	     is placed into the buffer specified by buf.  Returns 0 upon success or an error code to indicate the reason for failure.

     firmware_malloc(size)

	     Allocates a region of wired kernel memory of size size.  Note: firmware_malloc() may block.

     firmware_free(buf, size)

	     Frees a region of memory previously allocated by firmware_malloc().

SEE ALSO

     autoconf(9), malloc(9), vnsubr(9)

HISTORY

     The firmload framework first appeared in NetBSD 4.0.

AUTHORS

     Jason Thorpe <thorpej@NetBSD.org>

BSD
								 January 17, 2006							       BSD

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

NAME

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

SYNOPSIS

     #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 */
     };

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

     int
     firmware_unregister(const char *imagename);

     const struct firmware *
     firmware_get(const char *imagename);

     void
     firmware_put(const struct firmware *fp, int flags);

DESCRIPTION

     The firmware abstraction provides a convenient interface for loading firmware images into the kernel, and for accessing such images from ker-
     nel components.

     A firmware image (or image for brevity) is an opaque block of data residing in kernel memory.  It is associated to a unique imagename which
     constitutes a search key, and to an integer version number, which is also an opaque piece of information for the firmware subsystem.

     An image is registered with the firmware subsystem by calling the function firmware_register(), and unregistered by calling
     firmware_unregister().  These functions are usually (but not exclusively) called by specially crafted kernel modules that contain the
     firmware image.  The modules can be statically compiled in the kernel, or loaded by /boot/loader, manually at runtime, or on demand by the
     firmware subsystem.

     Clients of the firmware subsystem can request access to a given image by calling the function firmware_get() with the imagename they want as
     an argument. If a matching image is not already registered, the firmware subsystem will try to load it using the mechanisms specified below
     (typically, a kernel module with the same name as the image).

API DESCRIPTION

     The kernel firmware API is made of the following functions:

     firmware_register() registers with the kernel an image of size datasize located at address data, under the name imagename.

     The function returns NULL on error (e.g. because an image with the same name already exists, or the image table is full), or a const struct
     firmware * pointer to the image requested.

     firmware_unregister() tries to unregister the firmware image imagename from the system. The function is successful and returns 0 if there are
     no pending references to the image, otherwise it does not unregister the image and returns EBUSY.

     firmware_get() returns the requested firmware image.  If the image is not yet registered with the system, the function tries to load it.
     This involves the linker subsystem and disk access, so firmware_get() must not be called with any locks (except for Giant).  Note also that
     if the firmware image is loaded from a filesystem it must already be mounted.  In particular this means that it may be necessary to defer
     requests from a driver attach method unless it is known the root filesystem is already mounted.

     On success, firmware_get() returns a pointer to the image description and increases the reference count for this image. On failure, the func-
     tion returns NULL.

     firmware_put() drops a reference to a firmware image.  The flags argument may be set to FIRMWARE_UNLOAD to indicate that firmware_put is free
     to reclaim resources associated with the firmware image if this is the last reference.  By default a firmware image will be deferred to a
     taskqueue(9) thread so the call may be done while holding a lock.	In certain cases, such as on driver detach, this cannot be allowed.

FIRMWARE LOADING MECHANISMS

     As mentioned before, any component of the system can register firmware images at any time by simply calling firmware_register().

     This is typically done when a module containing a firmware image is given control, whether compiled in, or preloaded by /boot/loader, or man-
     ually loaded with kldload(8).  However, a system can implement additional mechanisms to bring these images in memory before calling
     firmware_register().

     When firmware_get() does not find the requested image, it tries to load it using one of the available loading mechanisms.	At the moment,
     there is only one, namely Loadable kernel modules:

     A firmware image named foo is looked up by trying to load the module named foo.ko, using the facilities described in kld(4).  In particular,
     images are looked up in the directories specified by the sysctl variable kern.module_path which on most systems defaults to
     /boot/kernel;/boot/modules.

     Note that in case a module contains multiple images, the caller should first request a firmware_get() for the first image contained in the
     module, followed by requests for the other images.

BUILDING FIRMWARE LOADABLE MODULES

     A firmware module is built by embedding the firmware image into a suitable loadable kernel module that calls firmware_register() on loading,
     and firmware_unregister() on unloading.

     Various system scripts and makefiles let you build a module by simply writing a Makefile with the following entries:

	     KMOD=   imagename
	     FIRMWS= image_file:imagename[:version]
	     .include <bsd.kmod.mk>

     where KMOD is the basename of the module; FIRMWS is a list of colon-separated tuples indicating the image_file's to be embedded in the mod-
     ule, the imagename and version of each firmware image.

     If you need to embed firmware images into a system, you should write appropriate entries in the <files.arch> file, e.g. this example is from
     sys/arm/xscale/ixp425/files.ixp425:

     ixp425_npe_fw.c			     optional npe_fw		     
	     compile-with    "${AWK} -f $S/tools/fw_stub.awk		     
			     IxNpeMicrocode.dat:npe_fw -mnpe -c${.TARGET}"   
	     no-implicit-rule before-depend local			     
	     clean	     "ixp425_npe_fw.c"
     #
     # NB: ld encodes the path in the binary symbols generated for the
     #	   firmware image so link the file to the object directory to
     #	   get known values for reference in the _fw.c file.
     #
     IxNpeMicrocode.fwo  optional npe_fw				     
	     dependency      "IxNpeMicrocode.dat"			     
	     compile-with    "${LD} -b binary -d -warn-common		     
				 -r -d -o ${.TARGET} IxNpeMicrocode.dat"     
	     no-implicit-rule						     
	     clean	     "IxNpeMicrocode.fwo"
     IxNpeMicrocode.dat 		     optional npe_fw		     
	     dependency      ".PHONY"					     
	     compile-with    "uudecode < $S/contrib/dev/npe/IxNpeMicrocode.dat.uu" 
	     no-obj no-implicit-rule					     
	     clean	     "IxNpeMicrocode.dat"

     Note that generating the firmware modules in this way requires the availability of the following tools: awk, Make, the compiler and the
     linker.

SEE ALSO

     module(9), kld(4)

     /usr/share/examples/kld/firmware

HISTORY

     The firmware system was introduced in FreeBSD 6.1.

AUTHORS

     This manual page was written by Max Laier <mlaier@FreeBSD.org>.

BSD
								  August 2, 2008							       BSD