Re: [Suit] SUIT architecture examples
Michael Richardson <mcr+ietf@sandelman.ca> Mon, 25 June 2018 23:18 UTC
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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: David Brown <david.brown@linaro.org>
cc: suit <suit@ietf.org>
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Date: Mon, 25 Jun 2018 19:15:05 -0400
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Subject: Re: [Suit] SUIT architecture examples
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David Brown <david.brown@linaro.org> wrote:
>> David Brown <david.brown@linaro.org> wrote:
>> > ### Dual CPU, other bus
>>
>> > This configuration has two or more CPUs, each having their own memory.
>> > There will be a communication channel between them, but it will be used
>> > as a peripheral, not via shared memory. In this case, each CPU will
>> > have to be responsible for its own firmware upgrade. It is likely that
>> > one of the CPUs will be considered a master, and will direct the other
>> > CPU to do the upgrade. This configuration is commonly used to offload
>> > specific work to other CPUs. Firmware dependencies are similar to the
>> > other solutions above, sometimes allowing only one image to be
>> > upgraded, other times requiring several to be upgraded atomically.
>> > Because the updates are happening on multiple CPUs, upgrading the two
>> > images atomically is challenging.
>>
>> Is there sometimes an ordering constrained between images?
>> I.e. upgrade CPU-A to version X, before you upgrade CPU-B to version X?
>>
>> Does the Manifest need to specify this constraint, or would it be implied?
> The current requirements as I am aware of them, only require the two
> images either be updated independently, or both be updated atomically.
> But, maybe it is worth being able to specify a one-directional
> ordering. In fact, a one-directional ordering could be used for the
> atomic case by just having each image specify a dependency on the
> other image at that version.
The specific case I am painfully familiar with is on many Qualcomm based
Android devices, where a particular main-CPU ROM images requires an baseband
RADIO image at least as new as X, or stuff seriously fails.
And sometimes a ROM image of Y, must have a RADIO image <= Z.
--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
-= IPv6 IoT consulting =-
- [Suit] SUIT architecture examples David Brown
- Re: [Suit] SUIT architecture examples Michael Richardson
- Re: [Suit] SUIT architecture examples David Brown
- Re: [Suit] SUIT architecture examples Michael Richardson