Re: [RFC][PATCH 1/2] firmware version management: add firmware_version()

[Martin Langer <martin-langer@gmx.de>]

On Sun, Jul 09, 2006 at 05:01:49PM +0200, Arjan van de Ven wrote:
> On Sun, 2006-07-09 at 14:21 +0200, Martin Langer wrote:
> > On Sat, Jul 08, 2006 at 03:49:57PM +0200, Marcel Holtmann wrote:
> > > Hi Arjan,
> > > 
> > > > > It would be good if a driver knows which firmware version will be 
> > > > > written to the hardware. I'm talking about external firmware files 
> > > > > claimed by request_firmware(). 
> > > > > 
> > > > > We know so many different firmware files for bcm43xx and it becomes 
> > > > > more and more complicated without some firmware version management.
> > > > > 
> > > > > This patch can create the md5sum of a firmware file. Then it looks into 
> > > > > a table to figure out which version number is assigned to the hashcode.
> > > > > That table is placed in the driver code and an example for bcm43xx comes 
> > > > > in my next mail. Any comments?
> > > > 
> > > > why does this have to happen on the kernel side? Isn't it a lot easier
> > > > and better to let the userspace side of things do this work, and even
> > > > have a userspace file with the md5->version mapping? Or are there some
> > > > practical considerations that make that hard to impossible?
> > > 
> > > I fully agree that we shouldn't put firmware versioning into the kernel
> > > drivers. The pattern you give to request_firmware() can be mapped to any
> > > file on the file system. And you also have the link to the device object
> > > and I prefer you export a sysfs file for the version so that the helper
> > > application loading the firmware can pick the right file.
> > 
> > Bcm43xx has no helper application to upload the firmware. 
> 
> yes it does. bcm43xx asks userspace to upload firmware (via
> request_firmware() ) and a userspace app (udev most of the time) will
> upload it. That app, eg udev, can do the md5sum and checking it against
> a list of "known good" firmwares. Voila problem solved ;)

I see. It's an interesting way that I didn't noticed. 
Thanks for the guidance.

Martin