Request for hosting a boot-firmware repository in u-boot git (denx and GitHub)

[Heinrich Schuchardt]

On 7/16/24 21:13, Tom Rini wrote:
> On Thu, Jun 20, 2024 at 04:35:39PM -0500, Nishanth Menon wrote:
>> Hi Team,
>>
>> We have briefly discussed this topic on IRC[1]. I would like to
>> propose a new boot-firmware repository similar to the Linux-firmware
>> repository under the aegis of u-boot hosting.
>>
>> In addition to TI, it looks like some NXP[2] and Rockchip[3]
>> platforms seem to require additional closed-source/open-source
>> binaries to have a complete bootable image. Distribution rights and
>> locations of these binaries are challenging, and there needs to be a
>> standard for how and where they are hosted for end users.
>>
>> Further, looking ahead to future architectures:
>> * IP firmware: More and more IP vendors are embedding their own
>>    "specialized controllers" and require firmware for the operation
>>    (similar to Rockchip's DDR controller, I guess),
>> * boot stage firmware: Additional stages of the boot process involve
>>    vendor intermediate firmware, such as power configuration.
>> * Security enclave binaries: While I see a few folks trying to have an
>>    open-source s/w architecture, many PKA and PQC systems still require
>>    prop binaries for IP reasons.
>>
>> NOTE: I am not judging any company(including TI) for reasons why some
>> firmware is proprietary, but I hate to have the end users and other
>> system (distro) maintainers have to deal with hell trying to make the
>> life of end users easy to live with.
>>
>> In the case of TI's K3 architecture devices, we have two binary blobs
>> that are critical for the boot process.
>>
>> 1. TIFS Firmware / DMSC firmware[4]—This is the security enclave
>>    firmware. It is often encrypted, and sources are not public (due to
>>    various business/regulatory reasons).
>> 2. DM Firmware[5] - There is a source in public in some cases and
>>    binary only in others - essentially limited function binary to be
>>    put up in the device management uC. In cases where the source is
>>    available, the build procedure is, in my personal opinion, pretty
>>    arcane, and even though in theory it is practical, in practice, not
>>    friendly - efforts are going to simplify it, even probably integrate
>>    it with a more opensource ecosystem, but that is talking "look at the
>>    tea leaves" stuff.
>> 3. Low Power Management (LPM) binaries: tifs stub: another encrypted
>>    binary that gives the tifs system context restore logic before
>>    retrieving tifs firmware and a corresponding DM restoration binary.
>>
>> All told, this is not unlike the situation that necessitated the
>> creation of a Linux firmware repository.
>>
>> Options that I see:
>>
>> 1. Let the status quo be - SoC vendors maintain random locations and
>>    random rules to maintain boot firmware.
>> 2. Ask Linux-firmware to host the binaries in a single canonical
>>    location
>> 3. Host a boot-firmware repository - u-boot repo may be the more
>>    logical location.
>>
>> * (1) isn't the correct answer.
>>
>> * (2) Though I haven't seen any policy from the Linux-firmware
>>    community mandating anything of the form, the binaries we are talking
>>    of may not belong to Linux-firmware as they aren't strictly speaking
>>    something Linux kernel will load (since the bootloader has that
>>    responsibility), and in some cases may not even directly talk to
>>    (security enclave or DDR firmware stuff). I am adding Josh to this
>>    mail to see if he has any opinions on the topic (but keeping
>>    from cross posting on linux-firmware list, unless folks feel it is
>>    OK).
>>
>> On (3):
>> Proposal:
>>
>> * Create a boot firmware repository in Denx and/or GitHub (if
>>    financials are a hurdle, I hope we can solve it as a community).
>> * Limit binaries only to those consumed part of the u-boot scope.
>>
>> * Limit binaries only to those that do not have an opensource project
>>    (Trusted Firmware-A/M, OP-TEE, etc..) or depend entirely on vendor
>>    source or are binary only in nature (subject to licensing terms below)
>> * Limit binaries to some pre-established size to prevent repository
>>    explosion - say, 512Kib?
>> * Follow the same rules of integration and licensing guidelines as
>>    Linux-firmware[6].
>> * Similar rules as Linux-firmware guidelines of ABI backward and
>>    forward compatibility.
>> * Set a workflow update flow and a compatibility requirements document
>>
>> If we agree to have boot firmware under the stewardship of u-boot, we
>> should also set other rules, which is excellent to discuss.
>>
>> Thoughts?
> 
> I believe that fundamentally, this is a problem that exists beyond both
> just "U-Boot needs some binaries" and "TI has some binaries that
> bootloaders need". So a generic solution is appropriate, and some sort
> of community-based hosting of these needs (with appropriate licensing
> from the IP owners) makes sense. Looking around at the binaries I have
> to keep locally to use NXP platforms, and TI platforms and Rockchip
> platforms, it's far from ideal. Having one place to get them all from
> would make life easier for a lot of developers and also frankly for a
> lot of end customers of these chips.
> 

Some thought needs to be given to the license implications of these 
binaries for operating system distributions.

A distro providing a combined binary consisting of U-Boot and closed 
source firmware might be interpreted as conflicting with U-Boot's GPL 
license.

Distributing the closed source binaries and U-Boot in separate packages 
according to their respective licenses and only assemble them on the 
target device via a post-installation script might be allowable.

Best regards

Heinrich