System-dt January 2020

system-dt@lists.openampproject.org

14 participants
16 discussions

Re: [System-dt] System Device Tree call - January

by Stefano Stabellini

Hi Nathalie, I would like to discuss and brainstorm the impact of the new system device tree nodes and concept over top level nodes such as memory and reserved-memory. (I also sent an email to the list to seed the discussion.) Cheers, Stefano On Sat, 18 Jan 2020, Nathalie Chan King Choy via System-dt wrote: > Hi all, > > > > Calling for agenda items for the System Device Tree call next Wednesday. > > > > Best regards, > > Nathalie > > > > -----Original Appointment----- > From: Nathalie Chan King Choy > Sent: Friday, December 13, 2019 3:39 PM > To: Nathalie Chan King Choy; system-dt(a)lists.openampproject.org > Cc: Raghuraman, Arvind; nathalie-ckc(a)kestrel-omnitech.com; Bruce Ashfield; Ed T. Mooring; Tony McDowell; Varis, Pekka; Milea, Danut Gabriel > (Danut); joakim.bech(a)linaro.org; Vincent Chardon; Markham, Joel (GE Global Research, US); robherring2(a)gmail.com; Kepa, Krzysztof (GE Global > Research); don.harbin(a)linaro.org; mathieu.poirier(a)linaro.org; Mark Hambleton; ilias.apalodimas(a)linaro.org; Ravikumar Chakaravarthy; Michael > May; Sakamoto, Hirokazu; Grant Likely; Petr Lukas; francois.ozog(a)linaro.org; Clément Leger; Loic PALLARDY; Tomas Evensen > Subject: System Device Tree call - January > When: Wednesday, January 22, 2020 9:00 AM-10:00 AM (UTC-08:00) Pacific Time (US & Canada). > Where: Zoom > > > > Hi all, > > > > Please join the call on Zoom: https://zoom.us/my/openampproject > > (If you need the meeting ID, it’s 9031895760) > > > > The notes from the previous call (Dec 11) can be found on the OpenAMP wiki at this link: > > https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2019#2019D… > > > > Action items from the previous call: > > * Rob: Reply to Stefano's latest response on list > > * All: Give a look at Stefano's example. Reply on the list about what doesn't work for your use case > > * Stefano: Bring access field back into the proposal for discussion sooner than later > > * Stefano: Include chosen node proposal in example to list so we have whole view of what we are trying to achieve. Target early 2020. > Looking for intent & what it's doing. Can get into syntax later. > > * Stefano: Note open question: What about top level memory node & reserved memory b/c that's connected? > > * Stefano: Start a thread on CPUs, chosen, memory, reserved memory nodes on list & we can discuss each of them & cases we might have missed > > * Bruce: Send out info on how to prune System DT into DTs. Target early 2020. > > * Nathalie: Confirm if Rob can make Jan 8th 22nd at 9am PST timeslot > > > > For info about the list, link to the archives, to unsubscribe yourself, or > > for someone to subscribe themselves, visit: > > https://lists.openampproject.org/mailman/listinfo/system-dt > > For information about the System Device Trees effort, including a link to > > the intro presentation from Linaro Connect SAN19: > > https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees > > > > Best regards, > > Nathalie C. Chan King Choy > > Project Manager focused on Open Source and Community > > > > > > > > >

4 years, 11 months

Re: [System-dt] System Device Tree call - January

by Nathalie Chan King Choy

Hi all, Calling for agenda items for the System Device Tree call next Wednesday. Best regards, Nathalie -----Original Appointment----- From: Nathalie Chan King Choy Sent: Friday, December 13, 2019 3:39 PM To: Nathalie Chan King Choy; system-dt(a)lists.openampproject.org Cc: Raghuraman, Arvind; nathalie-ckc(a)kestrel-omnitech.com; Bruce Ashfield; Ed T. Mooring; Tony McDowell; Varis, Pekka; Milea, Danut Gabriel (Danut); joakim.bech(a)linaro.org; Vincent Chardon; Markham, Joel (GE Global Research, US); robherring2(a)gmail.com; Kepa, Krzysztof (GE Global Research); don.harbin(a)linaro.org; mathieu.poirier(a)linaro.org; Mark Hambleton; ilias.apalodimas(a)linaro.org; Ravikumar Chakaravarthy; Michael May; Sakamoto, Hirokazu; Grant Likely; Petr Lukas; francois.ozog(a)linaro.org; Clément Leger; Loic PALLARDY; Tomas Evensen Subject: System Device Tree call - January When: Wednesday, January 22, 2020 9:00 AM-10:00 AM (UTC-08:00) Pacific Time (US & Canada). Where: Zoom Hi all, Please join the call on Zoom: https://zoom.us/my/openampproject (If you need the meeting ID, it's 9031895760) The notes from the previous call (Dec 11) can be found on the OpenAMP wiki at this link: https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2019#2019D… Action items from the previous call: * Rob: Reply to Stefano's latest response on list * All: Give a look at Stefano's example. Reply on the list about what doesn't work for your use case * Stefano: Bring access field back into the proposal for discussion sooner than later * Stefano: Include chosen node proposal in example to list so we have whole view of what we are trying to achieve. Target early 2020. Looking for intent & what it's doing. Can get into syntax later. * Stefano: Note open question: What about top level memory node & reserved memory b/c that's connected? * Stefano: Start a thread on CPUs, chosen, memory, reserved memory nodes on list & we can discuss each of them & cases we might have missed * Bruce: Send out info on how to prune System DT into DTs. Target early 2020. * Nathalie: Confirm if Rob can make Jan 8th 22nd at 9am PST timeslot For info about the list, link to the archives, to unsubscribe yourself, or for someone to subscribe themselves, visit: https://lists.openampproject.org/mailman/listinfo/system-dt For information about the System Device Trees effort, including a link to the intro presentation from Linaro Connect SAN19: https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees Best regards, Nathalie C. Chan King Choy Project Manager focused on Open Source and Community

4 years, 11 months

software domains and top level nodes

by Stefano Stabellini

Hi all, I would like to follow-up on system device tree and specifically on one of the action items from the last call. Rob raised the interesting question of what is the interaction between the new system device tree concepts and the top level nodes (memory, reserved-memory, cpus, chosen). I am going to write here my observations. As a short summary, the system device tree concepts are: - Multiple top level "cpus,cluster" nodes to describe heterogenous CPU clusters. - A new "indirect-bus" which is a type of bus that does not automatically map to the parent address space. - An address-map property to express the different address mappings of the different cpus clusters and can be used to map indirect-bus nodes. These new nodes and properties allow us to describe multiple heterogenous cpus clusters with potentially different address mappings, which can be expressed using indirect-bus and address-map. We also have new concepts for software domains configurations: - Multiple "openamp,domain" nodes (currently proposed under /chosen) to specify software configurations and MPU configurations. - A new "access" property under each "openamp,domain" node with links to nodes accessible from the cpus cluster. Openamp,domain nodes allow us to define the cpus cluster and set of hardware resources that together form a software domain. The access property defines the list of resources available to one particular cluster and maps well into MPU configurations (sometimes called "firewall configurations" during the calls.) See the attached full example. I am going to go through the major top level nodes and expand on how the new concepts affect them. /cpus ===== /cpus is the top level node that contains the description of the cpus in the system. With system device tree, it is not the only cpus cluster, additional cpus clusters can be described by other top level nodes compatible with "cpus,cluster". However, /cpus remains the default cluster. An OS reading device tree should assume that it is running on /cpus. From a compatibility perspective, if an OS doesn't understand or recognize the other "cpus,cluster" nodes, it can ignore them, and just process /cpus. Buses compatible with "indirect-bus" do not map automatically to the parent address space, which means that /cpus won't be able to access them, unless an address-map property is specified under /cpus to express the mapping. This is the only new limitation introduced for /cpus. Again, from a compatibility perspective an OS that doesn't understand the address-map property would just ignore both it and the bus, so again, it is an opt-in new functionality. So far in my examples "openamp,domain" nodes refer to "cpus,cluster" nodes only, not to /cpus. There is a question on whether we want to allow "openamp,domain" nodes to define a software domain running on /cpus. We could go either way, but for simplicity I think we can avoid it. "openamp,domain" nodes express accessibility restrictions while /cpus is meant to be able to access everything by default. If we want to specify hard accessibility settings for all clusters, it is possible to write a pure system device tree without /cpus, where all cpus clusters are described by "cpus,cluster" nodes and there is no expectation that an OS will be able to use it without going through some transformations by lopper (or other tools.) /chosen ======= The /chosen node is used for software configurations, such as bootargs (Linux command line). When multiple "openamp,domains" nodes are present the configurations directly under /chosen continue to refer to the software running on /cpus, while domain specific configurations need to go under each domain node. As an example: - /chosen/bootargs refers to the software running on /cpus - /chosen/openamp_r5/bootargs refers to the openamp_r5 domain /memory ======= The /memory node describes the main memory in the system. Like for any device node, all cpus clusters can address it. indirect-bus and address-map can be used to express addressing differences. It might be required to carve out special memory reservations for each domain. These configurations are expressed under /reserved-memory as we do today for any other reserved regions. /reserved-memory ================ /reserved-memory is used to describe particular reserved memory regions for special use by software. With system device tree /reserved-memory becomes useful to describe domain specific memory reservations too. Memory ranges for special use by "openamp,domain" nodes are expressed under /reserved-memory following the usual set of rules. Each "openamp,domain" node links to any relevant reserved-memory regions using the access property. The rest is to be used by /cpus. For instance: - /reserved-memory/memory_r5 is linked and used by /chosen/openamp_r5 - other regions under /reserved-memory, not linked by any "openamp,domain" nodes, go to the default /cpus We should use a specific compatible string to identify reserved memory regions meant for openamp,domain nodes, so that a legacy OS will safely ignore them. I added compatible = "openamp,domain-memory-v1"; to the example under the /reserved-memory/memory_r5.

4 years, 11 months

System Device Tree call - January

by Nathalie Chan King Choy

Hi all, Please join the call on Zoom: https://zoom.us/my/openampproject (If you need the meeting ID, it's 9031895760) The notes from the previous call (Dec 11) can be found on the OpenAMP wiki at this link: https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2019#2019D… Action items from the previous call: * Rob: Reply to Stefano's latest response on list * All: Give a look at Stefano's example. Reply on the list about what doesn't work for your use case * Stefano: Bring access field back into the proposal for discussion sooner than later * Stefano: Include chosen node proposal in example to list so we have whole view of what we are trying to achieve. Target early 2020. Looking for intent & what it's doing. Can get into syntax later. * Stefano: Note open question: What about top level memory node & reserved memory b/c that's connected? * Stefano: Start a thread on CPUs, chosen, memory, reserved memory nodes on list & we can discuss each of them & cases we might have missed * Bruce: Send out info on how to prune System DT into DTs. Target early 2020. * Nathalie: Confirm if Rob can make Jan 8th 22nd at 9am PST timeslot For info about the list, link to the archives, to unsubscribe yourself, or for someone to subscribe themselves, visit: https://lists.openampproject.org/mailman/listinfo/system-dt For information about the System Device Trees effort, including a link to the intro presentation from Linaro Connect SAN19: https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees Best regards, Nathalie C. Chan King Choy Project Manager focused on Open Source and Community

4 years, 11 months

Re: [System-dt] Calling for agenda items: System Device Tree call - January

by Nathalie Chan King Choy

Hi all, Stefano has recommended to push the call out a couple weeks, to give more time for things to progress. Calendar update will be sent momentarily. If you have recently subscribed to the system-dt list and don't have the calendar invitation, please let me know & I will send it to you. Best regards, Nathalie From: System-dt <system-dt-bounces(a)lists.openampproject.org> On Behalf Of Nathalie Chan King Choy via System-dt Sent: Monday, January 6, 2020 2:23 PM To: system-dt(a)lists.openampproject.org Subject: [System-dt] Calling for agenda items: System Device Tree call - January EXTERNAL EMAIL Happy New Year! This Wednesday, Jan 8th is the next System Device Tree call. Please send your suggestions for agenda items. Thanks & regards, Nathalie -----Original Appointment----- From: Nathalie Chan King Choy Sent: Friday, December 13, 2019 3:39 PM To: Nathalie Chan King Choy; system-dt(a)lists.openampproject.org<mailto:system-dt@lists.openampproject.org> Cc: Raghuraman, Arvind; nathalie-ckc(a)kestrel-omnitech.com<mailto:nathalie-ckc@kestrel-omnitech.com>; Bruce Ashfield; Ed T. Mooring; Tony McDowell; Varis, Pekka; Milea, Danut Gabriel (Danut); joakim.bech(a)linaro.org<mailto:joakim.bech@linaro.org>; Vincent Chardon; Markham, Joel (GE Global Research, US); robherring2(a)gmail.com<mailto:robherring2@gmail.com>; Kepa, Krzysztof (GE Global Research); don.harbin(a)linaro.org<mailto:don.harbin@linaro.org>; mathieu.poirier(a)linaro.org<mailto:mathieu.poirier@linaro.org>; Mark Hambleton; ilias.apalodimas(a)linaro.org<mailto:ilias.apalodimas@linaro.org>; Ravikumar Chakaravarthy; Michael May; Sakamoto, Hirokazu Subject: System Device Tree call - January When: Wednesday, January 8, 2020 9:00 AM-10:00 AM (UTC-08:00) Pacific Time (US & Canada). Where: Zoom Hi all, Please join the call on Zoom: https://zoom.us/my/openampproject (If you need the meeting ID, it's 9031895760) The notes from the previous call (Dec 11) can be found on the OpenAMP wiki at this link: https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2019#2019D… Action items from the previous call: * Rob: Reply to Stefano's latest response on list * All: Give a look at Stefano's example. Reply on the list about what doesn't work for your use case * Stefano: Bring access field back into the proposal for discussion sooner than later * Stefano: Include chosen node proposal in example to list so we have whole view of what we are trying to achieve. Target early 2020. Looking for intent & what it's doing. Can get into syntax later. * Stefano: Note open question: What about top level memory node & reserved memory b/c that's connected? * Stefano: Start a thread on CPUs, chosen, memory, reserved memory nodes on list & we can discuss each of them & cases we might have missed * Bruce: Send out info on how to prune System DT into DTs. Target early 2020. * Nathalie: Confirm if Rob can make Jan 8th at 9am PST timeslot For info about the list, link to the archives, to unsubscribe yourself, or for someone to subscribe themselves, visit: https://lists.openampproject.org/mailman/listinfo/system-dt For information about the System Device Trees effort, including a link to the intro presentation from Linaro Connect SAN19: https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees Best regards, Nathalie C. Chan King Choy Project Manager focused on Open Source and Community

4 years, 11 months

Calling for agenda items: System Device Tree call - January

by Nathalie Chan King Choy

Happy New Year! This Wednesday, Jan 8th is the next System Device Tree call. Please send your suggestions for agenda items. Thanks & regards, Nathalie -----Original Appointment----- From: Nathalie Chan King Choy Sent: Friday, December 13, 2019 3:39 PM To: Nathalie Chan King Choy; system-dt(a)lists.openampproject.org Cc: Raghuraman, Arvind; nathalie-ckc(a)kestrel-omnitech.com; Bruce Ashfield; Ed T. Mooring; Tony McDowell; Varis, Pekka; Milea, Danut Gabriel (Danut); joakim.bech(a)linaro.org; Vincent Chardon; Markham, Joel (GE Global Research, US); robherring2(a)gmail.com; Kepa, Krzysztof (GE Global Research); don.harbin(a)linaro.org; mathieu.poirier(a)linaro.org; Mark Hambleton; ilias.apalodimas(a)linaro.org; Ravikumar Chakaravarthy; Michael May; Sakamoto, Hirokazu Subject: System Device Tree call - January When: Wednesday, January 8, 2020 9:00 AM-10:00 AM (UTC-08:00) Pacific Time (US & Canada). Where: Zoom Hi all, Please join the call on Zoom: https://zoom.us/my/openampproject (If you need the meeting ID, it's 9031895760) The notes from the previous call (Dec 11) can be found on the OpenAMP wiki at this link: https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2019#2019D… Action items from the previous call: * Rob: Reply to Stefano's latest response on list * All: Give a look at Stefano's example. Reply on the list about what doesn't work for your use case * Stefano: Bring access field back into the proposal for discussion sooner than later * Stefano: Include chosen node proposal in example to list so we have whole view of what we are trying to achieve. Target early 2020. Looking for intent & what it's doing. Can get into syntax later. * Stefano: Note open question: What about top level memory node & reserved memory b/c that's connected? * Stefano: Start a thread on CPUs, chosen, memory, reserved memory nodes on list & we can discuss each of them & cases we might have missed * Bruce: Send out info on how to prune System DT into DTs. Target early 2020. * Nathalie: Confirm if Rob can make Jan 8th at 9am PST timeslot For info about the list, link to the archives, to unsubscribe yourself, or for someone to subscribe themselves, visit: https://lists.openampproject.org/mailman/listinfo/system-dt For information about the System Device Trees effort, including a link to the intro presentation from Linaro Connect SAN19: https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees Best regards, Nathalie C. Chan King Choy Project Manager focused on Open Source and Community

4 years, 11 months

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System-dt January 2020