Hi Arnaud, On 18.06.2018 11:32, Arnaud Pouliquen wrote: > Hi Oleksij, > > On 06/15/2018 06:37 PM, Oleksij Rempel wrote: >> Hi Arnaud, >> >> On Fri, Jun 15, 2018 at 03:21:19PM +0200, Arnaud Pouliquen wrote: >>> Hi Oleksij, >>> >>> Nice to see that we have the same needs. >>> We push several month ago an RFC based on something similar but i hope >>> more generic... >>> could you have a look? >>> >>> https://www.spinics.net/lists/linux-remoteproc/msg01823.html >> >> I took a look at dt binding. >> It would be really better to not redefine device nodes again. >> DT is providing HW description and if it is still the same IP core >> then most probably it is still the same from all CPUs. Most probably >> there is different interrupt controller and memory offset, but all other >> parts should be the same. >> In long term it would be great to reduce duplicated information which is >> needed to added system developer. > This is a valid point. We are also thinking about this. But just > disabling a peripheral that is used seems also not logic from our point > of view. Right now I don't see any thing bad on disabling it. For master CPU it is indeed disabled and should not be accesable. What is your argumentation about this? > Furthermore how to you manage followings use cases: > - peripheral clock is not the same for master and remote processor > => you potentially need to redefine the clocks IMO, not devicetree specific discussion > - clock, regulator or pin are not managed by the Linux if peripheral is > assigned to the remote processor, but controlled by the remote processor > directly (isolation, protection on shared resource access...). > => In this case we must not handle the resource in Linux. IMO, not devicetree specific discussion > - Need a specific management of a peripheral, due to secure, isolation, > or any other reason related to the platform. > => specific driver that can be bind as srm child (platform srm_dev). IMO, not devicetree specific discussion > To sum-up. We name shared (or system) resources every resources that > have to be shared between the master and the remote processor. The list > of these resources depends on the platform (and on peripheral of a > platform). That's why we decide to redefine the node. sorry, i can't follow here. I don't claim to replace your solution, especially if you have working code I would be happy to take it over ASAP. > In fact the good solution could be in the middle of this both design > solutions. Means choice between redefining the node properties or just > provide an handle to the soc one. For this we are thinking about a > phandle to the soc node. > something like ("parent-device" naming is just for the example) > m4_uart1 { > assigned-clock-rates = <240000000>; > parent-device = { &uart1}; > }; > > Another advantage of a phandle would be to be able to check that the > device is disabled on Linux side and could offer the possibility to > switch the peripheral between master and slave during the runtime. Is it a workaround for a system without devicetree overlay? I don't see why we should provide extra container for not really extra information. Or do I miss something? > To finish, an additional information: We are implementing on top of SRM > a dynamic part based on rpmsg that allows to reconfigure the shared > resource to allows for instance to: > - change the clock rate > - change pin states > - change regulator constraints > According to first discussion with Bjorn, we need to share this part > also to present the global picture ,we would like to propose. Ok, so it looks like we are working on same thing. And you probably already have most of the code to make this work. Did you made Linux implementation only for Master or both (Master and Slave) parts? >> >>> Could be nice if we could find a generic solution... >> >> I would be happy to have generic solution. > > Our solution is a base for discussion. If several companies are > interested in, any feedback and contributions to have a generic solution > is welcome. > And of course we need the approval of the maintainers on the design. i'm sure, every thing will be OK ;) >> >>> Best Regards >>> Arnaud >>> >>> On 06/15/2018 01:57 PM, Oleksij Rempel wrote: >>>> On AMP systems we need to make sure that some device >>>> nodes are not used by main system and reserved for >>>> external system. Some of configuration should be >>>> maintained by main system. For example clocks and pins. >>>> >>>> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> >>>> --- >>>> .../devicetree/bindings/remoteproc/imx-rproc.txt | 13 +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/remoteproc/imx-rproc.txt b/Documentation/devicetree/bindings/remoteproc/imx-rproc.txt >>>> index fbcefd965dc4..40bec03e094c 100644 >>>> --- a/Documentation/devicetree/bindings/remoteproc/imx-rproc.txt >>>> +++ b/Documentation/devicetree/bindings/remoteproc/imx-rproc.txt >>>> @@ -15,6 +15,7 @@ Required properties: >>>> Optional properties: >>>> - memory-region list of phandels to the reserved memory regions. >>>> (See: ../reserved-memory/reserved-memory.txt) >>>> +- remote-nodes list of device node phandels used by remote system. >>>> >>>> Example: >>>> m4_reserved_sysmem1: cm4@80000000 { >>>> @@ -25,9 +26,21 @@ Example: >>>> reg = <0x81000000 0x80000>; >>>> }; >>>> >>>> + /* node reserved for rproc */ >>>> + &uart1 { >>>> + assigned-clock-rates = <240000000>; >>>> + status = "disabled"; >>>> + }; >>>> + >>>> + &gpt2 { >>>> + assigned-clock-rates = <24000000>; >>>> + status = "disabled"; >>>> + }; >>>> + >>>> imx7d-cm4 { >>>> compatible = "fsl,imx7d-cm4"; >>>> memory-region = <&m4_reserved_sysmem1>, <&m4_reserved_sysmem2>; >>>> syscon = <&src>; >>>> clocks = <&clks IMX7D_ARM_M4_ROOT_CLK>; >>>> + remote-nodes = <&gpt2>, <&uart1>; >>>> }; >>>> >>> >> >
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