Messages in this thread | | | Date | Thu, 29 May 2008 15:12:46 -0400 | From | Jeff Garzik <> | Subject | Re: RFC: Moving firmware blobs out of the kernel. |
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David Woodhouse wrote: > I'm kind of hoping that this is going to be one of those topics that > resolves itself -- but just in case it isn't, I'd like to discuss it at > the kernel summit: > > I'd like to remove all firmware blobs from the kernel source tree. > > With the intention of making that less contentious, I've done the > following: > > I've added support to the firmware loader for finding firmware in a > special section of the static kernel, so that using request_firmware() > no longer forces you to use an initrd or udev. You can build _arbitrary_ > firmware files into your kernel, if you want to. Whether you're allowed > to distribute the resulting vmlinux or not is still a question you ought > to ask your lawyer. > > I'm working on converting drivers over to use request_firmware(), and > shifting their firmware blobs into .ihex files in a firmware/ directory > of the source tree. For each one, I'm giving the option of continuing to > build it in statically, using the above mechanism. > > I've implemented a 'make firmware_install' Kbuild target, which takes > all those firmware blobs and installs them somewhere where udev can load > them on request. > > By the time the kernel summit comes around, we should have made decent > progress on moving _all_ the firmware blobs to the firmware/ directory. > And at that point I'd like to remove them completely, to a separate git > tree and tarball. Those who really want to build them in to their static > kernel would still be able to, but it wouldn't be the default behaviour.
I like your idea, all the way to the point where you actually remove the firmware file from the kernel tree :)
I think it's a good move to make the firmware files standalone and not #include'd as a C header file, but it's just plain easier to ship them with the kernel tree in a lot of cases. $FOO-firmware packages in Fedora prove other methods of firmware distribution are quite usable, but that does not therefore imply that in-kernel built-in firmwares have no utility.
Personally, living in an imaginary all-open-source world, I wouldn't mind seeing firmware source for firmware built into drivers, a la drivers/scsi/aic7xxx/aicasm/, living in the kernel tree.
If the firmware has a compatible license and is required for critical operations like booting the machine, built-in firmware should remain an option. For certain embedded cases, I could certainly see that in-kernel firmware being the best method for firmware distribution, for both $Platform's users and $Platform's developers.
Jeff
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