Re: Firmware compression

[Andrew Doran <ad%NetBSD.org@localhost>]

On Sun, May 04, 2008 at 05:33:14PM +0200, Manuel Bouyer wrote:

> On Sun, May 04, 2008 at 03:53:03PM +0100, Andrew Doran wrote:
> > We have a meg or two of firmware images in the i386 GENERIC kernel, which is
> > insane. I was thinking of adding a function that would use kmem_alloc+zlib
> > to decompress images, and another to optionally free the decompressed image.
> > It would probably also be good to add a simple program under dev/microcode
> > to take a blob and spit out a compressed array in a C file.
> 
> Maybe we could decompress it directly to DMA-safe memory ?
> I guess in the general case, the firmware is going to be loaded
> though DMA by the target system, isn't it ?

That's an interesting idea. I've had a look through the the drivers that
load firmware images, and they seem to do it in quite different ways. Some
load fimware at splnet() for example, some write it out word at a time,
others use DMA. Without the ability to test them I think it's easier to
allocate a memory area and free it when not needed any more.

Andrew