On Tue 06 Sep 11:32 PDT 2016, Linus Torvalds wrote:

On Tue, Sep 6, 2016 at 10:46 AM, Bjorn Andersson
[off-list ref] wrote:

quoted

Linus, I reversed the order of your questions/answers to fit my answer
better.

Nobody has actually answered the "why don't we just tie the firmware
and module together" question.

The answer to this depends on the details of the suggestion; but
generally there's a much stronger bond between the kernel and the driver
than between the driver and the firmware in my cases.

E.g. we have a single remoteproc driver loading and controlling the
Hexagon DSP found in several Qualcomm platforms, so a single kernel
binary could (practically) load hundreds of variants of the firmware.

Both the kernel binary and the firmware in this example are side-loaded
onto the device during development - independently of each other, as
they are developed by different teams (or maybe even different
companies).

I assume that you're not suggesting to actually tie the module together,
as that would be practically difficult and a waste of resources.

Which leaves us with the suggestion that we should store the kernel
module with the firmware file, which is just infeasible from a few
practical reasons - again mostly related to the development flow and how
the files are contained on the devices.

Really. If the driver doesn't work without the firmware, then why the
hell is it separated from it in the first place?

In several cases we have a single remoteproc driver controlling several
different co-processors. Further more with the aspiration of being able
to run the same kernel binary (including modules) on more than one
product this is simply not feasible.

As I said above, beyond development there are hundreds of variants of
these firmware files in products - each weighting in at 10-50MB.

The firmware loading part (remoteproc) doesn't care about these
differences and the functional drivers attaching to the services
provided by the firmware can handle the differences between them.

The hack is a hack, and it just sounds *stupid*.

This I totally agree with.

Regards,
Bjorn