Hi Pascal, On Thu, Jun 20, 2019 at 02:59:20PM +0000, Pascal Van Leeuwen wrote: > > From: Antoine Tenart <antoine.tenart@xxxxxxxxxxx> > > On Wed, Jun 19, 2019 at 02:37:44PM +0000, Pascal Van Leeuwen wrote: > > > > From: Antoine Tenart <antoine.tenart@xxxxxxxxxxx> > > > > On Tue, Jun 18, 2019 at 07:56:24AM +0200, Pascal van Leeuwen wrote: > > > > > > > In addition to this, the direction the kernel has taken was to *remove* > > > > binary firmwares from its source code. I'm afraid adding this is a > > > > no-go. > > > > > > For a HW engineer, there really is no fundamental difference between > > > control register contents or an instruction word. They can both have > > > the exact same effects internal to the HW. > > > If I had disguised this as a handful of config reg writes writing > > > some #define'd magic values, probably no one would have even noticed. > > > > I do not fully agree. If this is comparable to configuring h/w > > registers, then you could probably have defines explaining why each bit > > is set and what it's doing. Which would be fine. > > > Strictly speaking, we (and probably most other HW vendors as well) don't do > that for every register bit either, not even in the official Programmer Manual. > Some bits are just "you don't need to know, just write this" :-) That's right... :-( > > > By that same definition, the tokens the driver generates for > > > processing could be considered "firmware" as well (as they are used by > > > the hardware in a very similar way) ... > > > > Right. The main difference here is we do have a clear definition of what > > the tokens are doing. Thanks to your explanation, if this firmware is > > really looking like the token we're using, the words have a defined > > structure and the magic values could be generated with proper defines > > and macros. And I think it's the main issue here: it's not acceptable to > > have an array of magic values. If you can give a meaning to those bits, > > I see no reason why it couldn't be added to the driver. > > > > (And I'm all for what you're trying to achieve here :)). > > > Now we're reaching a tricky subject. Because I think if some people here > find out those token bits are explicitly documented in the driver, they > will not be so happy ... (don't worry, I won't wake any sleeping dogs :-) > We provide this information to our customers under NDA, but it's > obviously quite sensitive information as it reveals a lot about the > inner workings of our HW design. > > The encoding of the microengine control words is considered even > more sensitive, so we don't even provide that under NDA. > Adding that to the driver will probably get me in trouble. I fully understand this. This is not perfect, but at least it's the way it is right now. > So maybe putting these images in /lib/firmware is unavoidable, but > I'd really like to hear some more opinions on that subject. Yes, you either have to choice to put it in /lib/firmware (and in the linux-firmwares project!) or to convince people to allow releasing this. We can wait for others to hop in on the discussion, of course. Thanks! Antoine -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
