Thanks,
Bill
-----Original Message-----
From: arm.ebbr-discuss-boun...@arm.com
[mailto:arm.ebbr-discuss-boun...@arm.com] On Behalf Of Grant Likely
Sent: Thursday, March 29, 2018 5:52 PM
To: arm.ebbr-disc...@arm.com; Da Xue
Subject: Re: [Arm.ebbr-discuss] Next steps for EBBR
On 29/03/2018 22:24, Da Xue wrote:
We expect the primary users of EBBR will be embedded & developer Arm
boards using U-Boot firmware and Devicetree machine description My
concern is around device tree and EFI variable storage for u-boot on
flash.
The two elephants in the room. How to handle device tree updates? Do
we track mainline? How to handle detection and addition of overlays?
Certainly issues to discuss while drafting EBBR.
We expect a distribution will be able to use the same software
(Distro Installer, Grub, Linux UEFI stub, Shim), and the same media
(installer images) on both embedded and server platforms
Are you referring to SBSA when you say "server platforms"? I don't see
why this has to be the case.
Yes, I'm talking about SBSA/SBBR compliant platforms. EBBR will
require a subset of what SBBR requires; essentially just enough of the
UEFI spec to execute a UEFI OS Loader from media or the network.
U-Boot implements this today, and a distro would be able to use the
exact same OSLoader/Installer on both SBSA/SBBR systems and EBBR
systems. That's part of the point of this exercise.
What do you mean when you say, "don't see why this has to be the case?"
What do you see as the alternative?
Linux distributions - Can make EBBR compliance a requirement for
support
Vendors haven't standardized boot rom sequence. Some SoC boot from SPI
first, other eMMC, and others SD card. This is a major pain point that
ARM/Linaro should address. I don't see why distributions should force
EBBR compliance when a simple u-boot script loading or scanning for a
Linux EFI stub suffices unless EBBR is incredibly simple and small. I
need to emphasize the simple and small part because it will also allow
EBBR to scale up and down.
Shouldn't be an issue for EBBR. EBBR is focused on the Firmware->OS
interface. It doesn't matter where the SoC boots U-Boot or Tianocore
from as long as firmware presents a consistent interface beyond that
point.
It also doesn't matter how U-Boot implements the boot interface. If
the U-Boot developers think a U-Boot script that searches for OS
Loaders in the correct order is the best implementation, then that is
just fine.
What is important is that the OS image must not need to contain
anything special in order to boot. ie. It must not require a script to
be installed on the media because the UEFI spec already specifies how
to find the boot program.
End users - EBBR will make it simpler to use embedded Arm boards
because
each board will not require special setup instructions or image
formats
Distributions will still need to explicitly have SoC family support in
their kernels.
Yes, that is a given.
It would be a lot of work (that will never get done) for
SoC vendors to abstract device classes and functions like Intel has for
UEFI.
For the boot time environment the abstractions are already there. U-Boot
implements the needed abstractions in the form of the U-Boot device
drivers. The UEFI APIs are mapped directly onto the U-Boot device model.
For runtime services you're right. There is no plan to implement a
runtime abstract device driver model.
On Thu, Mar 29, 2018 at 6:47 AM, Grant Likely <grant.lik...@arm.com
<mailto:grant.lik...@arm.com>> wrote:
On 29/03/2018 10:06, Alexander Graf wrote:
Does Windows for IoT run in aarch64 mode by now? If not, we
might have a problem :).
I wouldn't call that a problem. It is up to Microsoft on whether or
not they care about an aarch64 port of Windows IoT. They may still
find EBBR useful for aarch32, and the whole point of having them
involved is they can share what they think would be valuable to
have
in the spec.
Cheers,
g.
Alex
Am 29.03.2018 um 09:34 schrieb Charles Garcia-Tobin
<charles.garcia-to...@arm.com
<mailto:charles.garcia-to...@arm.com>>:
Nice!
On 29/03/2018, 06:14, "arm.ebbr-discuss-boun...@arm.com
<mailto:arm.ebbr-discuss-boun...@arm.com> on behalf of Dong
Wei" <arm.ebbr-discuss-boun...@arm.com
<mailto:arm.ebbr-discuss-boun...@arm.com> on behalf of
dong....@arm.com <mailto:dong....@arm.com>> wrote:
I presented EBBR and its intent at the UEFI Plugfest
this week. Microsoft people in attendance seemed very
interested. They are to follow up with their IoT team to
see
if they would be interested in working with us on this...
- DW
-
-----Original Message-----
From: Grant Likely
Sent: Wednesday, March 28, 2018 8:57 AM
To: arm.ebbr-discuss <arm.ebbr-disc...@arm.com
<mailto:arm.ebbr-disc...@arm.com>>
Cc: Alexander Graf <ag...@suse.de
<mailto:ag...@suse.de>>; wmi...@ti.com
<mailto:wmi...@ti.com>; Dong Wei <dong....@arm.com
<mailto:dong....@arm.com>>; Yang Zhang
<yang.zh...@96boards.org <mailto:yang.zh...@96boards.org>>;
Peter Robinson <pbrobin...@redhat.com
<mailto:pbrobin...@redhat.com>>; Ard Biesheuvel
<ard.biesheu...@linaro.org
<mailto:ard.biesheu...@linaro.org>>; rob.herr...@linaro.org
<mailto:rob.herr...@linaro.org>; Tom Rini
<tr...@konsulko.com <mailto:tr...@konsulko.com>>;
boot-architecture@lists.linaro.org
<mailto:boot-architecture@lists.linaro.org>
Subject: Next steps for EBBR
Hi folks,
At Linaro Connect in Hong Kong this week there has
been
some EBBR (Embedded Base Boot Requirements) discussions.
One
of the interesting angles that came up is that the 96Boards
project would like to specify EBBR in an upcoming
specification, so they need EBBR to be published and
realistic. The Fedora and SuSE representatives are very
supportive of that notion, because it gives them a path to
support boards conforming to that spec. A few of us here
had
a quick meeting to work out how we could make that happen.
I'm sending this to the EBBR alias, but I'm also
cc'ing
the boot-architecture@lists.linaro.org
<mailto:boot-architecture@lists.linaro.org> mailing list so
that we've got an archive.
Attendees:
Alexander Graf (SuSE)
Grant Likely (Arm)
Bill Mills (TI)
Peter Robinson (Red Hat/Fedora)
Dong Wei (Arm)
Yang Zhang (Linaro/96Boards)
Notes:
- We discussed the purpose & intent of EBBR
- Is intended to document the basic requirements on
firmware to
implement a 'standard' boot path on embedded
boards.
- Needed by distros (Fedora, SuSE, Debian, etc) to
support boards out
of the box
- Needed by OpenEmbedded, Yocto, etc to get away
from custom platform
specific hacks
- Establishes a foundation for implementing
SecureBoot, A/B updates,
and other useful boot scenarios in a
consistent way.
- We expect the primary users of EBBR will be
embedded & developer Arm
boards using U-Boot firmware and Devicetree
machine description
- We expect a distribution will be able to use the
same software
(Distro Installer, Grub, Linux UEFI stub, Shim),
and the same media
(installer images) on both embedded and server
platforms
- We discussed what EBBR should contain
- Will document interfaces and standards; not
specific projects
- Will specify a subset of the UEFI specification.
- Boot services are in
- Runtime services can be implemented with
empty stubs
- Need to work out what to do with runtime
setting
of variables
- For the first release ("EBBR level 0"), it will
track features
available in upstream
- In concrete terms this means EBBR can be
implemented with upstream
U-Boot or Tianocore.
- Subsequent releases will refine the requirements
as needed and as
software improves
- Expected target audience
- embedded board vendors - Gives strong guidance on
how to make a
widely supported board
- Linux distributions - Can make EBBR compliance a
requirement for
support
- End users - EBBR will make it simpler to use
embedded Arm boards
because each board will not require special setup
instructions or
image formats
- Roadmap
- 96Boards wants to specify EBBR compliance in an
upcoming spec to be
announced at Linaro Connect in the fall (about 6
months time)
- Need to have general agreement on the content of
EBBR well before
that (2-3 months?)
- Need to have a final EBBR 1.0 release before the
96Boards spec
announcement
- Work items:
- Transcode existing EBBR draft into text markup
and check into Git
repo
- Review current EBBR draft and compare with
available U-Boot
functionality
- Identify changes required to EBBR spec
- Identify gaps in U-Boot functionality that
can
reasonably be
addressed in the EBBR v1.0 timeframe
- Draft roadmap of goals - particularly focusing
on functionality
required by Linux distributions
- Stand up issue tracker (GitHub?)
Open Questions:
- Can the EBBR document be drafted in public? (Dong to
follow up
internally at Arm)
- Where do the Engineering resources come from to make
EBBR a reality
- General call for engineering effort to be
committed by interested
parties
- Can we use a cut-down LuvOS or UEFI SCT as a
specification conformance
test suite?
Actions:
- Dong to have Arm internal discussion about moving
EBBR draft process
onto GitHub or similar
- Markup candidate: Sphinx-doc with
reStructuredText
markup
- Grant to organize a regular weekly meeting to track
EBBR drafting
process
- Make sure to include Tom Rini and Ard Biesheuvel
- Yang to socialize with 96Boards partners to prepare
them for EBBR
compliance
- (Unassigned) Create a hosting page with issue
tracker
for EBBR -- TBD
after Dong finishes internal due diligence on
moving
EBBR drafting to
a public repository
- Probably GitHub
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