* ACPI support for System Control and Management Interface (SCMI) @ 2020-04-10 2:26 Hanjun Guo 2020-04-14 2:55 ` Thanu Rangarajan 2020-04-14 10:54 ` Sudeep Holla 0 siblings, 2 replies; 5+ messages in thread From: Hanjun Guo @ 2020-04-10 2:26 UTC (permalink / raw) To: Sudeep Holla, 'Thanu Rangarajan', Charles Garcia-Tobin Cc: John Garry, 'Matteo Carlini', Shameerali Kolothum Thodi, Linuxarm, Jonathan Cameron, linux-arm-kernel Hi Sudeep, We are working on the enablement of SCMI for Kunepeng920, which is a server chip using ACPI, but I didn't see the ACPI support in the mainline kernel for SCMI. Kunpeng920 and the upcomming Kunpeng930 have thermal sensors and other system management features which needs the SCMI for abstraction layer, do we have plan to support ACPI for SCMI? Happy easter! Thanks Hanjun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ACPI support for System Control and Management Interface (SCMI) 2020-04-10 2:26 ACPI support for System Control and Management Interface (SCMI) Hanjun Guo @ 2020-04-14 2:55 ` Thanu Rangarajan 2020-04-14 10:54 ` Sudeep Holla 1 sibling, 0 replies; 5+ messages in thread From: Thanu Rangarajan @ 2020-04-14 2:55 UTC (permalink / raw) To: guohanjun, Sudeep Holla, Charles Garcia-Tobin, Souvik Chakravarty Cc: John Garry, Matteo Carlini, Shameerali Kolothum Thodi, Linuxarm, Jonathan Cameron, linux-arm-kernel + Souvik On 10/04/2020, 07:57, "Hanjun Guo" <guohanjun@huawei.com> wrote: Hi Sudeep, We are working on the enablement of SCMI for Kunepeng920, which is a server chip using ACPI, but I didn't see the ACPI support in the mainline kernel for SCMI. Kunpeng920 and the upcomming Kunpeng930 have thermal sensors and other system management features which needs the SCMI for abstraction layer, do we have plan to support ACPI for SCMI? Happy easter! Thanks Hanjun IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ACPI support for System Control and Management Interface (SCMI) 2020-04-10 2:26 ACPI support for System Control and Management Interface (SCMI) Hanjun Guo 2020-04-14 2:55 ` Thanu Rangarajan @ 2020-04-14 10:54 ` Sudeep Holla 2020-04-14 12:08 ` Souvik Chakravarty 1 sibling, 1 reply; 5+ messages in thread From: Sudeep Holla @ 2020-04-14 10:54 UTC (permalink / raw) To: Hanjun Guo Cc: 'Thanu Rangarajan', Sudeep Holla, souvik.chakravarty, John Garry, Linuxarm, Shameerali Kolothum Thodi, Matteo Carlini, Jonathan Cameron, linux-arm-kernel, Charles Garcia-Tobin On Fri, Apr 10, 2020 at 10:26:41AM +0800, Hanjun Guo wrote: > Hi Sudeep, > > We are working on the enablement of SCMI for Kunepeng920, > which is a server chip using ACPI, but I didn't see the > ACPI support in the mainline kernel for SCMI. > > Kunpeng920 and the upcomming Kunpeng930 have thermal > sensors and other system management features which > needs the SCMI for abstraction layer, do we have plan > to support ACPI for SCMI? > Yes and No. Yes, because the same SCMI compliant firmware needs to work with ACPI as SCMI is designed so. No, because we don't plan to add another SCMI layer below ACPI in the kernel. ACPI specification was extended to support special PCC types to support the same. IIUC things like sensors are supported using power meter objects in ACPI and you must be able to use PCC opregion for it or any custom mechanism to achieve that. However one need to add PCC opregion handler in Linux. The main idea is you must use existing ACPI methods and we don't plan to add anything special for SCMI. SCMI Perf protocol is compatible with CPPC. We can discuss details once you explore PCC opregion or any alternative you come up with. I am no ACPI firmware expert and I reckon you may have other interesting ideas. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: ACPI support for System Control and Management Interface (SCMI) 2020-04-14 10:54 ` Sudeep Holla @ 2020-04-14 12:08 ` Souvik Chakravarty 2020-04-18 2:16 ` Hanjun Guo 0 siblings, 1 reply; 5+ messages in thread From: Souvik Chakravarty @ 2020-04-14 12:08 UTC (permalink / raw) To: Sudeep Holla, guohanjun Cc: Thanu Rangarajan, Sudeep Holla, John Garry, Linuxarm, Shameerali Kolothum Thodi, Matteo Carlini, Jonathan Cameron, linux-arm-kernel, Charles Garcia-Tobin > From: Sudeep Holla <sudeep.holla@arm.com> > Subject: Re: ACPI support for System Control and Management Interface > (SCMI) > > On Fri, Apr 10, 2020 at 10:26:41AM +0800, Hanjun Guo wrote: > > Hi Sudeep, > > > > We are working on the enablement of SCMI for Kunepeng920, which is a > > server chip using ACPI, but I didn't see the ACPI support in the > > mainline kernel for SCMI. > > > > Kunpeng920 and the upcomming Kunpeng930 have thermal sensors and > other > > system management features which needs the SCMI for abstraction layer, > > do we have plan to support ACPI for SCMI? > > > > Yes and No. > > Yes, because the same SCMI compliant firmware needs to work with ACPI as > SCMI is designed so. > > No, because we don't plan to add another SCMI layer below ACPI in the > kernel. ACPI specification was extended to support special PCC types to > support the same. IIUC things like sensors are supported using power meter > objects in ACPI and you must be able to use PCC opregion for it or any > custom mechanism to achieve that. However one need to add PCC opregion > handler in Linux. The main idea is you must use existing ACPI methods and > we don't plan to add anything special for SCMI. Additionally, if you already have an SCMI compliant firmware that uses Shared Memory based transport, it is compatible with PCC Type 3 Channels in ACPI. > > SCMI Perf protocol is compatible with CPPC. We can discuss details once you > explore PCC opregion or any alternative you come up with. I am no ACPI > firmware expert and I reckon you may have other interesting ideas. > > -- > Regards, > Sudeep IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ACPI support for System Control and Management Interface (SCMI) 2020-04-14 12:08 ` Souvik Chakravarty @ 2020-04-18 2:16 ` Hanjun Guo 0 siblings, 0 replies; 5+ messages in thread From: Hanjun Guo @ 2020-04-18 2:16 UTC (permalink / raw) To: Souvik Chakravarty, Sudeep Holla Cc: Thanu Rangarajan, John Garry, Linuxarm, Shameerali Kolothum Thodi, Matteo Carlini, Jonathan Cameron, linux-arm-kernel, Charles Garcia-Tobin Hi Sudeep, Souvik, On 2020/4/14 20:08, Souvik Chakravarty wrote: >> From: Sudeep Holla <sudeep.holla@arm.com> >> Subject: Re: ACPI support for System Control and Management Interface >> (SCMI) >> >> On Fri, Apr 10, 2020 at 10:26:41AM +0800, Hanjun Guo wrote: >>> Hi Sudeep, >>> >>> We are working on the enablement of SCMI for Kunepeng920, which is a >>> server chip using ACPI, but I didn't see the ACPI support in the >>> mainline kernel for SCMI. >>> >>> Kunpeng920 and the upcomming Kunpeng930 have thermal sensors and >> other >>> system management features which needs the SCMI for abstraction layer, >>> do we have plan to support ACPI for SCMI? >>> >> >> Yes and No. >> >> Yes, because the same SCMI compliant firmware needs to work with ACPI as >> SCMI is designed so. >> >> No, because we don't plan to add another SCMI layer below ACPI in the >> kernel. ACPI specification was extended to support special PCC types to >> support the same. IIUC things like sensors are supported using power meter >> objects in ACPI and you must be able to use PCC opregion for it or any >> custom mechanism to achieve that. However one need to add PCC opregion >> handler in Linux. The main idea is you must use existing ACPI methods and >> we don't plan to add anything special for SCMI. > > Additionally, if you already have an SCMI compliant firmware that uses > Shared Memory based transport, it is compatible with PCC Type 3 Channels > in ACPI. We had a disscusion interally (with firmware folks) and this works for our sensor usecase too, thanks! > >> >> SCMI Perf protocol is compatible with CPPC. We can discuss details once you >> explore PCC opregion or any alternative you come up with. I am no ACPI >> firmware expert and I reckon you may have other interesting ideas. Sensor works via PCC channels, and SCMI based clock/reset/cpufreq also have other abstraction level to make it work on ACPI based system, so for now no more requirements are needed, I will update if we got new ones :) Thanks Hanjun _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
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