firmware loading

[km b]

On 5/12/07, Matthew Dillon <dillon at apollo.backplane.com> wrote:

    The root filesystem will not be mounted during driver attach so
    the kernel will not have access to the filesystem.  But there are
    a couple of other possibilities:
    (1) You could embed the firmware as a const char [] array in the
    source code itself.  It would depend how big the firmware image is...
    if it's really big I'd rather not embed it in source code.
    There might also be a copyright issue with the firmware that prevents
    it from being embeddable in the source code.
i thought of it but i can't understand the implications of Intel's
firmware license.
    (2) The firmware could be loaded into kernel memory as a module by
    the boot loader.  The boot loader does have access to the root
    filesystem (usually).  The driver would then be able to locate and
    access it at attach time.
    (3) There is a kernel firmware loading facility in
    sys/kern/kern_firmware.c.  Again, the file cannot be loaded at
    attach time but this way you could have an ioctl that just passes
    the filename to the driver as part of the RC boot sequence
    and the driver could then use the kern_firmware.c facility to
    actually get an image map into kernel memory.
    Method #1 or #3 is probably the best way to do it.  Method #2 requires
    more configuration glue and changes in the loader config.
I think (3) is the best way to do it as it would relieve me from
writing the user-space utility.
cheers
kmb
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