On 30/05/2018 08:07, Udit Kumar wrote:
-----Original Message-----
From: Rob Herring [mailto:[email protected]]
Sent: Tuesday, May 29, 2018 8:32 PM
To: Udit Kumar <[email protected]>
Cc: Architecture Mailman List <[email protected]>;
[email protected]; [email protected]
Subject: Re: Issue#9 Document hardware need (if any)
On Fri, May 25, 2018 at 8:47 PM, Udit Kumar <[email protected]> wrote:
-----Original Message-----
From: Rob Herring [mailto:[email protected]]
Sent: Friday, May 25, 2018 8:18 PM
To: Udit Kumar <[email protected]>
Cc: Architecture Mailman List <[email protected]>;
[email protected]; [email protected]
Subject: Re: Issue#9 Document hardware need (if any)
On Fri, May 25, 2018 at 1:44 AM, Udit Kumar <[email protected]> wrote:
Hi
At present, I don't see any specific hardware requirement for EBBR
except
ARMv8 CPU. Current document covers it very well.
You have to have block storage. Perhaps UEFI implies that. Boards
like the CHIP only have raw NAND and a USB connector by default. So is USB
MS enough?
Yes but such need is not must to have EBBR running.
I don't follow.
I meant, what hardware features a SOC must have to run EBBR.
This include IPs/CPU architecture etc.
NAND/USB could be optional, this is not must for EBBR.
I think being explicit with h/w requirements implied by UEFI would be
a good thing. If I'm designing a board, I don't want to have to sort
thru UEFI specs to distill down a bullet list of h/w reqs.
I like to cover here, all on/off chip components could be IP/peripherals needed
for EBBR.
Like if USB is present, minimum version of xchi or echi needs to be supported
by hardware.
One look at XHCI or EHCI drivers and the variations across SoCs will tell you
that
just specifying those specs is pointless. But it is probably worth saying
something
about USB. Perhaps saying USB host
port(s) (more than 1?) required and the firmware must support booting from
USB.
I put USB as an example.
Please refer SBSA, which mandate the version of ECHI/XCHI
should be supported. Also this specify other IPs too like Timer, UART, GiC etc
IMO, such strict hardware requirement for EBBR will not be useful.
Right. EBBR differs from SBBR in that SBBR assumes a 'standard'
architecture that doesn't require platform specific drivers to boot and
install. EBBR permits non-standard devices, with the tradeoff that the
OS needs explicit support for the SoC/Platform.
The follow-on from this is it puts a high priority on getting drivers
upstreamed. If a driver is not upstream, it is unlikely that
SUSE/Fedora/Debian/etc will ship with support.
However, EBBR could provide recommendations on hardware to guarantee
support. Perhaps as an appendix? Alternately, for completeness we could
create an EBSA (Embedded Base System Architecture) to perform the same
job that SBSA does in the server space.
g.
Rob
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