OPP: Allow OPP table to be used for power-domains
v8 cover OPP: Allow OPP table to be used for power-domains
Hi,
Now that the performance state of PM domains are supported by the kernel (merged in linux-next), I am trying once again to define the bindings which we dropped until the code is merged first.
Summary:
Power-domains can also have their active states and this patchset enhances the OPP binding to define those.
The power domains can use the OPP bindings mostly as is. Though there are some changes required to support special cases:
- Allow "operating-points-v2" to contain multiple phandles for power domain providers providing multiple domains.
- A new property "required-opp" is added for the devices to specify the minimum required OPP of the master domain or any other type of device.
- Allow some of the OPP properties to accept magic values (firmware dependent) as the OS doesn't know the real freq/voltage values.
V7->V8:
- V7 1/2 divided into two patches. 1/3 is unchanged from V7.
- 2/3 renamed the property from "power-domain-opp" to "required-opp", as suggested by Rob.
- Added Ulf's reviewed-by for 1/3 and 3/3.
--
viresh
Viresh Kumar (3):
OPP: Allow OPP table to be used for power-domains
OPP: Introduce "required-opp" property
OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Documentation/devicetree/bindings/opp/opp.txt | 19 +++++++ .../devicetree/bindings/power/power_domain.txt | 65 ++++++++++++++++++++++ 2 files changed, 84 insertions(+)
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PATCH v8 1/3 OPP: Allow OPP table to be used for power-domains
Power-domains can also have their active states and this patch enhances the OPP binding to define those. The power domains can use the OPP bindings as is, with one additional change to Allow "operating-points-v2" property to contain multiple phandles for power domain providers providing multiple domains.
--- Documentation/devicetree/bindings/opp/opp.txt | 5 +++++ Documentation/devicetree/bindings/power/power_domain.txt | 6 ++++++ 2 files changed, 11 insertions(+)
Documentation/devicetree/bindings/opp/opp.txt +5 -0
@@ -45,6 +45,11 @@ Devices supporting OPPs must set their "operating-points-v2" property with phandle to a OPP table in their DT node. The OPP core will use this phandle to find the operating points for the device. +This can contain more than one phandle for power domain providers that provide +multiple power domains. That is, one phandle for each power domain. If only one +phandle is available, then the same OPP table will be used for all power domains +provided by the power domain provider. + If required, this can be extended for SoC vendor specific bindings. Such bindings should be documented as Documentation/devicetree/bindings/power/<vendor>-opp.txt and should have a compatible description like: "operating-points-v2-<vendor>".
Documentation/devicetree/bindings/power/power_domain.txt +6 -0
@@ -40,6 +40,12 @@ phandle arguments (so called PM domain specifiers) of length specified by the domain's idle states. In the absence of this property, the domain would be considered as capable of being powered-on or powered-off. +- operating-points-v2 : Phandles to the OPP tables of power domains provided by + a power domain provider. If the provider provides a single power domain only + or all the power domains provided by the provider have identical OPP tables, + then this shall contain a single phandle. Refer to ../opp/opp.txt for more + information. + Example: power: power-controller@12340000 {
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Quoted 6 lines · Viresh Kumar
Power-domains can also have their active states and this patch enhances the OPP binding to define those. The power domains can use the OPP bindings as is, with one additional change to Allow "operating-points-v2" property to contain multiple phandles for power domain providers providing multiple domains.
Quoted 6 lines
Reviewed-by Ulf Hansson <[email protected]>Signed-off-by Viresh Kumar <[email protected]>--- Documentation/devicetree/bindings/opp/opp.txt | 5 +++++ Documentation/devicetree/bindings/power/power_domain.txt | 6 ++++++ 2 files changed, 11 insertions(+)
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PATCH v8 2/3 OPP: Introduce "required-opp" property
In reply to Viresh KumarDevices have inter-dependencies some times. For example a device that needs to run at 800 MHz, needs another device (e.g. Its power domain) to be configured at a particular operating performance point.
This patch introduces a new property "required-opp" which can be present directly in a device's node (if it doesn't need to change its OPPs), or in device's OPP nodes. More details on the property can be seen in the binding itself.
--- Documentation/devicetree/bindings/opp/opp.txt | 8 +++ .../devicetree/bindings/power/power_domain.txt | 59 ++++++++++++++++++++++ 2 files changed, 67 insertions(+)
Documentation/devicetree/bindings/opp/opp.txt +8 -0
@@ -159,6 +159,14 @@ properties. - status: Marks the node enabled/disabled. +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an + OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / {
Documentation/devicetree/bindings/power/power_domain.txt +59 -0
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Re: [PATCH V8 2/3] OPP: Introduce "required-opp" property
Quoted 71 lines · Viresh Kumar
Devices have inter-dependencies some times. For example a device that needs to run at 800 MHz, needs another device (e.g. Its power domain) to be configured at a particular operating performance point.
This patch introduces a new property "required-opp" which can be present directly in a device's node (if it doesn't need to change its OPPs), or in device's OPP nodes. More details on the property can be seen in the binding itself.
Signed-off-by Viresh Kumar <[email protected]>--- Documentation/devicetree/bindings/opp/opp.txt | 8 +++ .../devicetree/bindings/power/power_domain.txt | 59 ++++++++++++++++++++++ 2 files changed, 67 insertions(+)Documentation/devicetree/bindings/opp/opp.txt +8
-0@@ -159,6 +159,14 @@ properties. - status: Marks the node enabled/disabled. +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an + OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / {Documentation/devicetree/bindings/power/power_domain.txt +29
-0@@ -126,4 +126,63 @@ The node above defines a typical PM domain consumer device, which is located inside a PM domain with index 0 of a power controller represented by a node with the label "power". +Optional properties: +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an + OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + +Example: +- OPP table for domain provider that provides two domains. + + domain0_opp_table: opp_table0 { + compatible = "operating-points-v2"; + + domain0_opp_0: opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <975000 970000 985000>; + }; + domain0_opp_1: opp-1100000000 { + opp-hz = /bits/ 64 <1100000000>; + opp-microvolt = <1000000 980000 1010000>; + }; + }; + + domain1_opp_table: opp_table1 { + compatible = "operating-points-v2"; + + domain1_opp_0: opp-1200000000 {
Documentation/devicetree/bindings/power/power_domain.txt The node above defines a typical PM domain consumer device, which is located · line 167
Quoted 10 lines
Documentation/devicetree/bindings/power/power_domain.txt +10
-0+ opp-hz = /bits/ 64 <1200000000>; + opp-microvolt = <975000 970000 985000>; + }; + domain1_opp_1: opp-1300000000 { + opp-hz = /bits/ 64 <1300000000>; + opp-microvolt = <1000000 980000 1010000>; + }; + }; + + parent: power-controller@12340000 {
Nitpick: Could you please change "parent" to "power", to be consistent with earlier examples.
Quoted 22 lines
Documentation/devicetree/bindings/power/power_domain.txt +20
-1+ compatible = "foo,power-controller"; + reg = <0x12340000 0x1000>; + #power-domain-cells = <1>; + operating-points-v2 = <&domain0_opp_table>, <&domain1_opp_table>; + }; + + leaky-device0@12350000 { + compatible = "foo,i-leak-current"; + reg = <0x12350000 0x1000>; + power-domains = <&parent 0>; + required-opp = <&domain0_opp_0>; + }; + + leaky-device1@12350000 { + compatible = "foo,i-leak-current"; + reg = <0x12350000 0x1000>; + power-domains = <&parent 1>; + required-opp = <&domain1_opp_1>; + }; + [1]. Documentation/devicetree/bindings/power/domain-idle-state.txt --
Quoted 2 lines
2.15.0.194.g9af6a3dea062
Besides the nitpick, feel free to add:
Kind regards
Uffe
Re: [PATCH V8 2/3] OPP: Introduce "required-opp" property
Quoted 2 lines · Ulf Hansson
Nitpick: Could you please change "parent" to "power", to be consistent with earlier examples.
Sure. Thanks for the review.
Signature · 1 line
viresh
Re: [PATCH V8 2/3] OPP: Introduce "required-opp" property
In reply to Viresh KumarQuoted 9 lines · Viresh Kumar
Devices have inter-dependencies some times. For example a device that needs to run at 800 MHz, needs another device (e.g. Its power domain) to be configured at a particular operating performance point.
This patch introduces a new property "required-opp" which can be present directly in a device's node (if it doesn't need to change its OPPs), or in device's OPP nodes. More details on the property can be seen in the binding itself.
Quoted 5 lines
Signed-off-by Viresh Kumar <[email protected]>--- Documentation/devicetree/bindings/opp/opp.txt | 8 +++ .../devicetree/bindings/power/power_domain.txt | 59 ++++++++++++++++++++++ 2 files changed, 67 insertions(+)
A couple of nits, otherwise:
Quoted 31 lines
Documentation/devicetree/bindings/opp/opp.txt +8
-0@@ -159,6 +159,14 @@ properties. - status: Marks the node enabled/disabled. +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an + OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / {Documentation/devicetree/bindings/power/power_domain.txt +3
-0@@ -126,4 +126,63 @@ The node above defines a typical PM domain consumer device, which is located inside a PM domain with index 0 of a power controller represented by a node with the label "power". +Optional properties: +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an
Documentation/devicetree/bindings/power/power_domain.txt The node above defines a typical PM domain consumer device, which is located · line 141
Quoted 10 lines
Documentation/devicetree/bindings/power/power_domain.txt +10
-0+ OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + +Example: +- OPP table for domain provider that provides two domains. + + domain0_opp_table: opp_table0 {
opp-table0
Documentation/devicetree/bindings/power/power_domain.txt The node above defines a typical PM domain consumer device, which is located · line 154
Quoted 13 lines
Documentation/devicetree/bindings/power/power_domain.txt +13
-0+ compatible = "operating-points-v2"; + + domain0_opp_0: opp-1000000000 { + opp-hz = /bits/ 64 <1000000000>; + opp-microvolt = <975000 970000 985000>; + }; + domain0_opp_1: opp-1100000000 { + opp-hz = /bits/ 64 <1100000000>; + opp-microvolt = <1000000 980000 1010000>; + }; + }; + + domain1_opp_table: opp_table1 {
opp-table1
Quoted 37 lines
Documentation/devicetree/bindings/power/power_domain.txt +33
-0+ compatible = "operating-points-v2"; + + domain1_opp_0: opp-1200000000 { + opp-hz = /bits/ 64 <1200000000>; + opp-microvolt = <975000 970000 985000>; + }; + domain1_opp_1: opp-1300000000 { + opp-hz = /bits/ 64 <1300000000>; + opp-microvolt = <1000000 980000 1010000>; + }; + }; + + parent: power-controller@12340000 { + compatible = "foo,power-controller"; + reg = <0x12340000 0x1000>; + #power-domain-cells = <1>; + operating-points-v2 = <&domain0_opp_table>, <&domain1_opp_table>; + }; + + leaky-device0@12350000 { + compatible = "foo,i-leak-current"; + reg = <0x12350000 0x1000>; + power-domains = <&parent 0>; + required-opp = <&domain0_opp_0>; + }; + + leaky-device1@12350000 { + compatible = "foo,i-leak-current"; + reg = <0x12350000 0x1000>; + power-domains = <&parent 1>; + required-opp = <&domain1_opp_1>; + }; + [1]. Documentation/devicetree/bindings/power/domain-idle-state.txtSignature · 1 line
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Re: [PATCH V8 2/3] OPP: Introduce "required-opp" property
In reply to Viresh KumarQuoted 8 lines · Viresh Kumar
Devices have inter-dependencies some times. For example a device that needs to run at 800 MHz, needs another device (e.g. Its power domain) to be configured at a particular operating performance point.
This patch introduces a new property "required-opp" which can be present directly in a device's node (if it doesn't need to change its OPPs), or in device's OPP nodes. More details on the property can be seen in the binding itself.
This is slightly updated based on Rob and Ulf's comments. Will apply it to the OPP tree with below diff.
Signature · 25 lines
viresh -------------------------8<------------------------- Subject: [PATCH] OPP: Introduce "required-opp" property Devices have inter-dependencies some times. For example a device that needs to run at 800 MHz, needs another device (e.g. Its power domain) to be configured at a particular operating performance point. This patch introduces a new property "required-opp" which can be present directly in a device's node (if it doesn't need to change its OPPs), or in device's OPP nodes. More details on the property can be seen in the binding itself. Reviewed-by: Ulf Hansson <[email protected]> Reviewed-by: Rob Herring <[email protected]> Signed-off-by: Viresh Kumar <[email protected]> --- Changes: - s/opp_table/opp-table for node names. - s/parent/power for domain alias. Documentation/devicetree/bindings/opp/opp.txt | 8 +++ .../devicetree/bindings/power/power_domain.txt | 59 ++++++++++++++++++++++ 2 files changed, 67 insertions(+)
Documentation/devicetree/bindings/opp/opp.txt +8 -0
@@ -159,6 +159,14 @@ properties. - status: Marks the node enabled/disabled. +- required-opp: This contains phandle to an OPP node in another device's OPP + table. It may contain an array of phandles, where each phandle points to an + OPP of a different device. It should not contain multiple phandles to the OPP + nodes in the same OPP table. This specifies the minimum required OPP of the + device(s), whose OPP's phandle is present in this property, for the + functioning of the current device at the current OPP (where this property is + present). + Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / {
Documentation/devicetree/bindings/power/power_domain.txt +59 -0
63 lines not on this page · raw message
PATCH v8 3/3 OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
In reply to Viresh KumarOn some platforms the exact frequency or voltage may be hidden from the OS by the firmware. Allow such configurations to pass magic values in the "opp-hz" or the "opp-microvolt" properties, which should be interpreted in a platform dependent way.
--- Documentation/devicetree/bindings/opp/opp.txt | 6 ++++++ 1 file changed, 6 insertions(+)
Documentation/devicetree/bindings/opp/opp.txt +6 -0
@@ -167,6 +167,12 @@ properties. functioning of the current device at the current OPP (where this property is present). + +On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware. + Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together. / {
Signature · 1 line
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Rob Herring
maintainerRe: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 16 lines · Viresh Kumar
On some platforms the exact frequency or voltage may be hidden from the OS by the firmware. Allow such configurations to pass magic values in the "opp-hz" or the "opp-microvolt" properties, which should be interpreted in a platform dependent way.
Reviewed-by Ulf Hansson <[email protected]>Signed-off-by Viresh Kumar <[email protected]>--- Documentation/devicetree/bindings/opp/opp.txt | 6 ++++++ 1 file changed, 6 insertions(+)Documentation/devicetree/bindings/opp/opp.txt +0
-0
Documentation/devicetree/bindings/opp/opp.txt properties. · line 174
Quoted 8 lines
Documentation/devicetree/bindings/opp/opp.txt +5
-0@@ -167,6 +167,12 @@ properties. functioning of the current device at the current OPP (where this property is present). + +On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware.
I'm still not convinced this is a good idea. If you have firmware partially managing things, then I think we should have platform specific bindings or drivers.
This is complex enough I'm not taking silence from Stephen as an okay.
Rob
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Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 8 lines · Rob Herring
Documentation/devicetree/bindings/opp/opp.txt properties. · line 174
Quoted 4 lines · Viresh Kumar
Documentation/devicetree/bindings/opp/opp.txt +4
-0+On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware.I'm still not convinced this is a good idea.
You were kind-of a few days back :)
lkml.kernel.org/r/CAL_JsqK-qtAaM_Ou5NtxcWR3F_q=8rMPJUm-VqGtKhbtWe5SAQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org
So here is the deal:
- I proposed "domain-performance-state" property for this stuff initially.
- But Kevin didn't like that and proposed reusing "opp-hz" and "opp-microvolt", which we all agreed to multiple times..
- And we are back to the same discussion now and its painful and time killing for all of us.
TBH, I don't have too strong preferences about any of the suggestions you guys have and I need you guys to tell me what binding changes to do here and I will do that.
Quoted 3 lines
If you have firmware
partially managing things, then I think we should have platform specific bindings or drivers.
What about the initial idea then, like "performance-state" for the power domains ? All platforms will anyway replicate that binding only.
Quoted 1 line
This is complex enough I'm not taking silence from Stephen as an okay.
Sure, but I am not sure how to make him speak :)
Signature · 5 lines
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Rob Herring
maintainerRe: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 10 lines · Viresh Kumar
Quoted 8 lines · Rob Herring
Documentation/devicetree/bindings/opp/opp.txt properties. · line 174
Quoted 4 lines · Viresh Kumar
Documentation/devicetree/bindings/opp/opp.txt +4
-0+On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware.I'm still not convinced this is a good idea.
Quoted 3 lines
You were kind-of a few days back :)
lkml.kernel.org/r/CAL_JsqK-qtAaM_Ou5NtxcWR3F_q=8rMPJUm-VqGtKhbtWe5SAQ@mail.gmail.com
Yeah, well that was before Stephen said anything.
Quoted 8 lines
So here is the deal:
- I proposed "domain-performance-state" property for this stuff initially.
- But Kevin didn't like that and proposed reusing "opp-hz" and "opp-microvolt", which we all agreed to multiple times..
- And we are back to the same discussion now and its painful and time killing for all of us.
There's bigger issues than where we put magic values as I raised in the other patch.
Quoted 10 lines
TBH, I don't have too strong preferences about any of the suggestions you guys have and I need you guys to tell me what binding changes to do here and I will do that.
Quoted 3 lines
If you have firmware
partially managing things, then I think we should have platform specific bindings or drivers.What about the initial idea then, like "performance-state" for the power domains ? All platforms will anyway replicate that binding only.
I don't really know. I don't really care either. I'll probably go along with what everyone agrees to, but the only one I see any agreement from is Ulf. Also, it is pretty vague as to what platforms will use this. You claimed you can support QCom scenarios, but there's really no evidence that that is true. What I don't want to see is this merged and then we need something more yet again in a few months for another platform.
Rob
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 37 lines · Rob Herring
Quoted 10 lines · Viresh Kumar
Quoted 8 lines · Rob Herring
Documentation/devicetree/bindings/opp/opp.txt properties. · line 174
Quoted 4 lines · Viresh Kumar
Documentation/devicetree/bindings/opp/opp.txt +4
-0+On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware.I'm still not convinced this is a good idea.
Quoted 3 lines
You were kind-of a few days back :)
lkml.kernel.org/r/CAL_JsqK-qtAaM_Ou5NtxcWR3F_q=8rMPJUm-VqGtKhbtWe5SAQ@mail.gmail.com
Yeah, well that was before Stephen said anything.
Quoted 8 lines
So here is the deal:
- I proposed "domain-performance-state" property for this stuff initially.
- But Kevin didn't like that and proposed reusing "opp-hz" and "opp-microvolt", which we all agreed to multiple times..
- And we are back to the same discussion now and its painful and time killing for all of us.There's bigger issues than where we put magic values as I raised in the other patch.
Quoted 8 lines
TBH, I don't have too strong preferences about any of the suggestions you guys have and I need you guys to tell me what binding changes to do here and I will do that.
Quoted 3 lines
If you have firmware
partially managing things, then I think we should have platform specific bindings or drivers.
Quoted 8 lines
Quoted 2 lines
What about the initial idea then, like "performance-state" for the power domains ? All platforms will anyway replicate that binding only.
I don't really know. I don't really care either. I'll probably go along with what everyone agrees to, but the only one I see any agreement from is Ulf. Also, it is pretty vague as to what platforms will use this. You claimed you can support QCom scenarios, but there's really no evidence that that is true.
Well, I sent out the code few days back based on these bindings and everyone can see how these bindings will get used now.
Quoted 3 lines
What I don't want to see is this
merged and then we need something more yet again in a few months for another platform.
Sure, I get your concerns.
So what we need now is:
- Stephen to start responding and clarify all the doubts he had as being silent isn't helping.
- Or Rajendra to post patches which can prove that this is usable. The last time I had a chat with him, he confirmed that he will post patches after 4.15-rc1 and he should have posted them by now, but he didn't :(
Signature · 1 line
viresh
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 15 lines · Viresh Kumar
Quoted 6 lines · Rob Herring
I don't really know. I don't really care either. I'll probably go along with what everyone agrees to, but the only one I see any agreement from is Ulf. Also, it is pretty vague as to what platforms will use this. You claimed you can support QCom scenarios, but there's really no evidence that that is true.
Well, I sent out the code few days back based on these bindings and everyone can see how these bindings will get used now.
Quoted 3 lines
What I don't want to see is this
merged and then we need something more yet again in a few months for another platform.
Quoted 6 lines
Sure, I get your concerns.
So what we need now is:
- Stephen to start responding and clarify all the doubts he had as being silent isn't helping.
What can I reply to specifically? From what I can tell, the patches have changed to this 'opp-required' thing in the past week and the position of 'generic OPP layer interprets magic values' doesn't look to have changed. Is that the summary? I can look deeply at the patches tomorrow.
Quoted 5 lines
- Or Rajendra to post patches which can prove that this is usable. The last time I had a chat with him, he confirmed that he will post patches after 4.15-rc1 and he should have posted them by now, but he didn't :(
I'd prefer either that, or some tree here that we can look at. I said this last time, I'm having a really hard time seeing how everything is going to work. The little drip of code, then DT binding, then maybe a small change in dts files, then maybe some code that uses the new APIs, etc. is pretty annoying. From my perspective you've chopped the problem up into pieces that don't stand on their own and then started sending patches for some parts without showing the overall result. It's like we're being taken on a ride in your development workflow, and we don't get to see what's coming around the corner, and the only assumption I can make is that you don't know either.
I'm actually confused how any of the code is even tested or used. It looks like things are getting merged without any users, for what exactly I'm not sure. Please, please, get an end-to-end solution going and actually use the code from day one on a real device that can use it.
Sorry for the rant, but my inbox keeps filling with patches for this series and I have no idea what's going on.
Signature · 6 lines
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Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 8 lines · Stephen Boyd
Quoted 4 lines · Viresh Kumar
So what we need now is:
- Stephen to start responding and clarify all the doubts he had as being silent isn't helping.
What can I reply to specifically?
I explained in detail how this stuff is going to get used last time you replied. Did you get a chance to look at that ? What am I supposed to do when you don't reply back to the clarifications I provide ?
https://marc.info/?l=linux-kernel&m=151202516128980&w=2
Quoted 5 lines
From what I can tell, the
patches have changed to this 'opp-required' thing in the past week and the position of 'generic OPP layer interprets magic values' doesn't look to have changed. Is that the summary? I can look deeply at the patches tomorrow.
Kind of yeah, because you didn't reply to my explanation on how the magic values are going to get used and so they never changed. Again, I don't have problems adding new property for performance-state thing or leave it for the platform, but I was sticking around the magic values because Kevin was strongly in favor of that earlier.
Quoted 6 lines
Quoted 4 lines
- Or Rajendra to post patches which can prove that this is usable. The last time I had a chat with him, he confirmed that he will post patches after 4.15-rc1 and he should have posted them by now, but he didn't :(
I'd prefer either that, or some tree here that we can look at.
I am quite sure Rajendra can help here, he had been testing this stuff on *real* hardware for ages now with me. This is what he shared with me earlier, based on what we have merged in the kernel today..
https://github.com/rrnayak/linux/commits/genpd-performance-state
Quoted 11 lines
I said this last time, I'm having a really hard time seeing how everything is going to work. The little drip of code, then DT binding, then maybe a small change in dts files, then maybe some code that uses the new APIs, etc. is pretty annoying. From my perspective you've chopped the problem up into pieces that don't stand on their own and then started sending patches for some parts without showing the overall result. It's like we're being taken on a ride in your development workflow, and we don't get to see what's coming around the corner, and the only assumption I can make is that you don't know either.
Quoted 5 lines
I'm actually confused how any of the code is even tested or used. It looks like things are getting merged without any users, for what exactly I'm not sure. Please, please, get an end-to-end solution going and actually use the code from day one on a real device that can use it.
There is just too much code, specially Qcom specific, and I can't fit all that in a single series really. Its going to be more annoying for people to see that. I used to keep some Qcom test code in the earlier series which got merged and was told by Rajendra that the Qcom stuff will get posted after 4.15-rc1, but that didn't happen. I can't post final code for that as it touches lots of things and its Qcom who needs to upstream it. Now how much test code can I keep supplying every time ?
I have already posted the code that will use these bindings few days back:
https://lkml.kernel.org/r/[email protected]
The only missing part left now (after bindings and above series) is, again, platform specific Qcom code to use it. Below is some dummy code to complete the story for you:
DT changes that shows two devices, mmc and dsp, using the performances states of domain:
foo: foo-power-domain@09000000 {
compatible = "foo,genpd";
#power-domain-cells = <0>;
operating-points-v2 = <&domain_opp_table>;
};
domain_opp_table: domain_opp_table {
compatible = "operating-points-v2";
domain_opp_1: opp00 {
opp-hz = /bits/ 64 <1>; //This is performances state
};
domain_opp_2: opp01 {
opp-hz = /bits/ 64 <2>;
};
domain_opp_3: opp02 {
opp-hz = /bits/ 64 <3>;
};
};
mmc@f7112000 {
compatible = "***";
***
power-domains = <&foo>;
operating-points-v2 = <&mmc_opp_table>;
};
mmc_opp_table: mmc-opp-table {
compatible = "operating-points-v2";
opp-shared;
opp00 {
opp-hz = /bits/ 64 <208000000>;
required-opp = <&domain_opp_1>;
};
opp01 {
opp-hz = /bits/ 64 <432000000>;
required-opp = <&domain_opp_2>;
};
opp02 {
opp-hz = /bits/ 64 <729000000>;
required-opp = <&domain_opp_2>;
};
opp03 {
opp-hz = /bits/ 64 <960000000>;
required-opp = <&domain_opp_3>;
};
};
dsp@f8152000 {
compatible = "***";
***
power-domains = <&foo>;
required-opp = <&domain_opp_2>;
};Platform specific power domain driver:
static int foo_set_performance(struct generic_pm_domain *genpd,
unsigned int state)
{
/* Set the state here */
return 0;
}static unsigned int foo_get_performance(struct generic_pm_domain *genpd,
struct dev_pm_opp *opp)
{
/*
* Simply return freq value as we passed the state in opp-hz. *
* If we choose to use platform-specific bindings instead of opp-hz,
* then only this routine requires to change to read the DT and provide
* the value from platform specific binding.
*/
return dev_pm_opp_get_freq(opp);
}
static const struct of_device_id pm_domain_of_match[] __initconst = {
{
.compatible = "foo,genpd",
},
{ },
};static int __init genpd_foo_init(void)
{
struct device_node *np;
struct generic_pm_domain *pd;
for_each_matching_node_and_match(np, pm_domain_of_match, NULL) {
pd = kzalloc(sizeof(*pd), GFP_KERNEL);
if (!pd)
return -ENOMEM;
pd->name = kstrdup_const(np->full_name, GFP_KERNEL);
if (!pd->name) {
of_node_put(np);
return -ENOMEM;
}
...
pd->set_performance_state = foo_set_performance;
pd->get_performance_state = foo_get_performance;
pm_genpd_init(pd, NULL, false);
of_genpd_add_provider_simple(np, pd);
}
return dev_pm_domain_attach(dev, false);
}device_initcall(genpd_foo_init);
There is nothing left after this from my end for performance-state stuff. That's all.
I don't mind rant from any of you or others (we are all good friends after all), but please please provide feedback. Its going to waste more time if you don't reply :)
Hope you have a very happy new year !!
--
viresh
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 22 lines · Viresh Kumar
Quoted 8 lines · Stephen Boyd
Quoted 4 lines · Viresh Kumar
So what we need now is:
- Stephen to start responding and clarify all the doubts he had as being silent isn't helping.
What can I reply to specifically?
I explained in detail how this stuff is going to get used last time you replied. Did you get a chance to look at that ? What am I supposed to do when you don't reply back to the clarifications I provide ?
https://marc.info/?l=linux-kernel&m=151202516128980&w=2
Quoted 5 lines
From what I can tell, the
patches have changed to this 'opp-required' thing in the past week and the position of 'generic OPP layer interprets magic values' doesn't look to have changed. Is that the summary? I can look deeply at the patches tomorrow.
Quoted 5 lines
Kind of yeah, because you didn't reply to my explanation on how the magic values are going to get used and so they never changed. Again, I don't have problems adding new property for performance-state thing or leave it for the platform, but I was sticking around the magic values because Kevin was strongly in favor of that earlier.
Could you please point to Kevin's comments and also include the reasoning behind magic values in the commit text for the patch? It would be very helpful to know why something is done a certain way. The two to three line commit text in this patch is not helpful right now.
Quoted 6 lines
Quoted 6 lines
Quoted 5 lines
- Or Rajendra to post patches which can prove that this is usable. The last time I had a chat with him, he confirmed that he will post patches after 4.15-rc1 and he should have posted them by now, but he didn't :(
Quoted 7 lines
Quoted 1 line
I'd prefer either that, or some tree here that we can look at.
I am quite sure Rajendra can help here, he had been testing this stuff on *real* hardware for ages now with me. This is what he shared with me earlier, based on what we have merged in the kernel today..
https://github.com/rrnayak/linux/commits/genpd-performance-state
Thanks for the pointer. That whole matching devices with of_match_device() is not looking good.
I don't see how we're going to convince each driver to move to using the OPP framework to set a performance state + clk frequency when they're going to want/need to have certain clks and regulators in hand to do something besides set the frequency or voltage. Probably we're going to have a hybrid approach, where some drivers can just set rate and voltage through OPP because it's fairly well fixed (think CPU or GPU frequency scaling), while other drivers are going to set frequency and voltage/performance state based on some calculation of their required frequency (think of display panels or even the uart baud rate or i2c bus frequency requirements).
For these other drivers, I don't really want to see the OPP framework proxy all the clk and regulator calls into the appropriate framework by wrapping clk_round_rate(), regulator_set_load(), etc. with opp_*() APIs. This becomes especially annoying if OPP framework is grabbing and holding these clk and regulator references in the core, instead of letting the driver figure that out and tell the OPP framework what resources it should operate on.
So really, I'm hoping that OPP framework "stays away" and acts as a data hole, sometimes, where we can look up the performance state for a particular frequency, but also have it do everything to set some particular performance state and frequency, etc. if the user wants that. And also OPP framework hopefully doesn't force a rigid set of frequencies that a particular clk can be set to, so that we can calculate frequencies for things like display panels based on height and width of the panel, or uart baud rate which is entirely use-case driven, and then ask OPP framework to tell us what the performance state of a particular domain would be if we are within some frequency range. Because sometimes we really can't determine every possible frequency that a clk can be running at, but we can figure out the maximum frequency that a clk can be running at for a particular voltage/performance state to support it.
Quoted 18 lines
Quoted 12 lines
I said this last time, I'm having a really hard time seeing how everything is going to work. The little drip of code, then DT binding, then maybe a small change in dts files, then maybe some code that uses the new APIs, etc. is pretty annoying. From my perspective you've chopped the problem up into pieces that don't stand on their own and then started sending patches for some parts without showing the overall result. It's like we're being taken on a ride in your development workflow, and we don't get to see what's coming around the corner, and the only assumption I can make is that you don't know either.
Quoted 5 lines
I'm actually confused how any of the code is even tested or used. It looks like things are getting merged without any users, for what exactly I'm not sure. Please, please, get an end-to-end solution going and actually use the code from day one on a real device that can use it.
Quoted 7 lines
There is just too much code, specially Qcom specific, and I can't fit all that in a single series really. Its going to be more annoying for people to see that. I used to keep some Qcom test code in the earlier series which got merged and was told by Rajendra that the Qcom stuff will get posted after 4.15-rc1, but that didn't happen. I can't post final code for that as it touches lots of things and its Qcom who needs to upstream it. Now how much test code can I keep supplying every time ?
I'm not asking for test code. A git tree pointer in cover letter is sufficient, with the full and complete solution to the problem. Then only a few patches out of the tree sent to the list is fine if you want to chunk it up into sub-topics. That way the list and reviewers aren't overloaded, but if someone wants to review the full picture they can do that easily.
Quoted 43 lines
I have already posted the code that will use these bindings few days back:
https://lkml.kernel.org/r/[email protected]
The only missing part left now (after bindings and above series) is, again, platform specific Qcom code to use it. Below is some dummy code to complete the story for you:
DT changes that shows two devices, mmc and dsp, using the performances states of domain:
foo: foo-power-domain@09000000 { compatible = "foo,genpd"; #power-domain-cells = <0>; operating-points-v2 = <&domain_opp_table>; }; domain_opp_table: domain_opp_table { compatible = "operating-points-v2"; domain_opp_1: opp00 { opp-hz = /bits/ 64 <1>; //This is performances state }; domain_opp_2: opp01 { opp-hz = /bits/ 64 <2>; }; domain_opp_3: opp02 { opp-hz = /bits/ 64 <3>; }; }; mmc@f7112000 { compatible = "***"; *** power-domains = <&foo>; operating-points-v2 = <&mmc_opp_table>; };
Quoted 7 lines
mmc_opp_table: mmc-opp-table {
compatible = "operating-points-v2";
opp-shared;
opp00 {
opp-hz = /bits/ 64 <208000000>;
required-opp = <&domain_opp_1>;It can have multiple phandles though, right? Makes me think it should have been called 'required-opps' instead.
Quoted 38 lines
}; opp01 { opp-hz = /bits/ 64 <432000000>; required-opp = <&domain_opp_2>; }; opp02 { opp-hz = /bits/ 64 <729000000>; required-opp = <&domain_opp_2>; }; opp03 { opp-hz = /bits/ 64 <960000000>; required-opp = <&domain_opp_3>; }; }; dsp@f8152000 { compatible = "***"; *** power-domains = <&foo>; required-opp = <&domain_opp_2>; };Platform specific power domain driver:
static int foo_set_performance(struct
generic_pm_domain*genpd,
unsigned int state){ /* Set the state here */ return 0; }
Quoted 9 lines
static unsigned int foo_get_performance(struct
generic_pm_domain*genpd,
structdev_pm_opp*opp)
{
/*
* Simply return freq value as we passed the state in opp-hz. *
* If we choose to use platform-specific bindings instead of opp-hz,
* then only this routine requires to change to read the DT and provide
* the value from platform specific binding.
If we wanted to change this function to do a platform specific thing, will we somehow get a way to access the DT node of the opp passed into this function? I don't see another way to do it.
Also, I don't see how the foo_get_performance function will use the genpd pointer passed here. Maybe that's never used?
Finally, I would think that a "getter" like this function would be informing the framework about what the current performance state is, not translating an OPP into a performance state. So the whole thing looks like a misnomer, and probably should be called something like xlate_opp_performance.
Signature · 2 lines
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 3 lines · Stephen Boyd
On 12/29, Viresh Kumar wrote:
Could you please point to Kevin's comments and also include the
https://lkml.kernel.org/r/[email protected]
Quoted 4 lines
reasoning behind magic values in the commit text for the patch? It would be very helpful to know why something is done a certain way. The two to three line commit text in this patch is not helpful right now.
Sure.
Quoted 4 lines
Thanks for the pointer. That whole matching devices with
of_match_device()is not looking good.
Yeah, I agree, but that was done because we didn't had these bindings then. Once these bindings are in place, we wouldn't require the of_match_device() thingy.
Quoted 11 lines
I don't see how we're going to convince each driver to move to using the OPP framework to set a performance state + clk frequency when they're going to want/need to have certain clks and regulators in hand to do something besides set the frequency or voltage. Probably we're going to have a hybrid approach, where some drivers can just set rate and voltage through OPP because it's fairly well fixed (think CPU or GPU frequency scaling), while other drivers are going to set frequency and voltage/performance state based on some calculation of their required frequency (think of display panels or even the uart baud rate or i2c bus frequency requirements).
The OPP framework doesn't (and shouldn't) force drivers to move to the dev_pm_opp_set_rate() API. That is optional and is provided to make user code simpler.
So, if a driver wants to handle everything by itself, it will just use the OPP core as "provider" for the data it needs and do everything by itself.
Quoted 8 lines
For these other drivers, I don't really want to see the OPP framework proxy all the clk and regulator calls into the appropriate framework by wrapping
clk_round_rate(),regulator_set_load(), etc. with opp_*() APIs. This becomes especially annoying if OPP framework is grabbing and holding these clk and regulator references in the core, instead of letting the driver figure that out and tell the OPP framework what resources it should operate on.
Sure.
Quoted 5 lines
So really, I'm hoping that OPP framework "stays away" and acts as a data hole, sometimes, where we can look up the performance state for a particular frequency, but also have it do everything to set some particular performance state and frequency, etc. if the user wants that.
That's how I see it as well.
Quoted 11 lines
And also OPP framework hopefully doesn't
force a rigid set of frequencies that a particular clk can be set to, so that we can calculate frequencies for things like display panels based on height and width of the panel, or uart baud rate which is entirely use-case driven, and then ask OPP framework to tell us what the performance state of a particular domain would be if we are within some frequency range. Because sometimes we really can't determine every possible frequency that a clk can be running at, but we can figure out the maximum frequency that a clk can be running at for a particular voltage/performance state to support it.
That makes sense to me. We can do that once we have someone who wants to use OPP core for such devices.
Quoted 6 lines
I'm not asking for test code. A git tree pointer in cover letter is sufficient, with the full and complete solution to the problem. Then only a few patches out of the tree sent to the list is fine if you want to chunk it up into sub-topics. That way the list and reviewers aren't overloaded, but if someone wants to review the full picture they can do that easily.
That's fine.
Quoted 10 lines
Quoted 7 lines
mmc_opp_table: mmc-opp-table { compatible = "operating-points-v2"; opp-shared; opp00 { opp-hz = /bits/ 64 <208000000>; required-opp = <&domain_opp_1>;It can have multiple phandles though, right? Makes me think it should have been called 'required-opps' instead.
Okay.
Quoted 10 lines
Quoted 9 lines
static unsigned int foo_get_performance(struct
generic_pm_domain*genpd,
structdev_pm_opp*opp)
{
/*
* Simply return freq value as we passed the state in opp-hz. *
* If we choose to use platform-specific bindings instead of opp-hz,
* then only this routine requires to change to read the DT and provide
* the value from platform specific binding.
Quoted 3 lines
If we wanted to change this function to do a platform specific thing, will we somehow get a way to access the DT node of the opp passed into this function?
Yes, we can do that. The OPP core already stores pointer to the node in the OPP structure, we will just need another API to expose that.
Quoted 2 lines
Also, I don't see how the
foo_get_performancefunction will use the genpd pointer passed here. Maybe that's never used?
It depends actually and I think its better to pass it anyway. What if a single driver is handling multiple genpds and wants to do things differently for them? It should know which genpd it is called for, looks like basic requirement to me.
Quoted 5 lines
Finally, I would think that a "getter" like this function would be informing the framework about what the current performance state is, not translating an OPP into a performance state. So the whole thing looks like a misnomer, and probably should be called something like
xlate_opp_performance.
Sure, I can name it anything.
So the question still stands, are we all okay for using magic values or we want platform specific properties ?
Signature · 1 line
viresh
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 6 lines · Viresh Kumar
Quoted 3 lines · Stephen Boyd
On 12/29, Viresh Kumar wrote:
Could you please point to Kevin's comments and also include the
Ok. That thread was months ago. Shocked I can't remember!
My read of Kevin's comments lead me to think he's saying that a generic 'domain-performance-state' property is worse than putting the numbers directly inside of the opp table with a comment above it. Now that's all fine, but now that we have required-opps binding we sort of have the domain-performance-state property again, but it's a phandle instead of a raw state number.
So we have
required-opps = <&perf_state>;
but what was proposed before was
domain-performance-state = <1>;
or Kevin's
opp-table = <100000 1>;
Quoted 1 line
From what I can tell, the domain-performance-state proposal was
at the same abstraction level as the OPP itself, but now that's moved to be inside of the power domain OPPs. So now we're talking about describing some power domains performance levels with the OPP binding, for a power domain, not describing a performance state for some unknown power domain that's associated with a device's OPP table.
The power domain is not running at any sort of frequency for us. It's using some particular voltage, but we may or may not know what that voltage is depending on the platform. This makes me see it as
power_domain_opp {
low: point0 {
opp-microvolt = <950000>
};
medium: point1 {
opp-microvolt = <975000>
};
high: point2 {
opp-microvolt = <1000000>
};
};for some sort of power domain that deals with voltages. This makes perfect sense. The power domain needs to be at some voltage and the binding says that. Honestly, the whole required-opps thing works great here and it's all wonderful, and it looks like can even be used for other OPP linking in the future, like connecting frequencies between CPUs and caches.
Where it starts to break down is when the voltage isn't known to the user, just some number that we've agreed means "low", "medium", "high" or whatever. Again, the binding looks similar:
power_domain_opp {
low: point0 {
qcom,corner = <0>;
};
medium: point1 {
qcom,corner = <10>;
};
high: point2 {
qcom,corner = <250>;
};
};but now the number is only meaningful to the power domain driver. What we really care about is associating some firmware specific information via the phandle to some frequency that a device is using. Behind the scenes of the firmware, that number is really being translated into some voltage, like opp-microvolt = <950000>, but we don't know what that is and it could vary at runtime.
It all feels really close, and it totally works for the non-magic value parts that we have to deal with, but I'm not convinced that we should stick the firmware specific information into some generic OPP property just so we don't have to review the binding again. Hopefully there's some other reason why we shouldn't come up with a firmware specific binding for this piece of information.
Quoted 10 lines
Quoted 7 lines
Quoted 3 lines
* If we choose to use platform-specific bindings instead of opp-hz,
* then only this routine requires to change to read the DT and provide
* the value from platform specific binding.If we wanted to change this function to do a platform specific thing, will we somehow get a way to access the DT node of the opp passed into this function?
Yes, we can do that. The OPP core already stores pointer to the node in the OPP structure, we will just need another API to expose that.
Great!
Quoted 8 lines
Quoted 3 lines
Also, I don't see how the
foo_get_performancefunction will use the genpd pointer passed here. Maybe that's never used?It depends actually and I think its better to pass it anyway. What if a single driver is handling multiple genpds and wants to do things differently for them? It should know which genpd it is called for, looks like basic requirement to me.
Ok, fair enough.
Quoted 8 lines
Quoted 6 lines
Finally, I would think that a "getter" like this function would be informing the framework about what the current performance state is, not translating an OPP into a performance state. So the whole thing looks like a misnomer, and probably should be called something like
xlate_opp_performance.Sure, I can name it anything.
Alright. Sounds like my read of the code is correct.
Quoted 4 lines
So the question still stands, are we all okay for using magic values or we want platform specific properties ?
Kevin?
Signature · 2 lines
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 11 lines · Stephen Boyd
My read of Kevin's comments lead me to think he's saying that a generic 'domain-performance-state' property is worse than putting the numbers directly inside of the opp table with a comment above it. Now that's all fine, but now that we have required-opps binding we sort of have the domain-performance-state property again, but it's a phandle instead of a raw state number.
So we have
required-opps = <&perf_state>;
Quoted 7 lines
but what was proposed before was
domain-performance-state = <1>;or Kevin's
opp-table = <100000 1>;
His concern was also on what will we do if "frequency" or other OPP properties aren't known tomorrow by the kernel but the firmware? In Qcom case, its just the voltage (corner) today, but it can very well be other properties tomorrow. Are we going to add more platform specific bindings then ? And this is the main reason why I have been aligned towards using something like this patch.
If we drop the magic-values idea and hence this patch, then we can either add a "domain-performance-state" property, which will only be used by the power domains or leave it for the platforms to add something like "qcom,corner".
All we are doing here is putting a voltage (corner) value, unknown to the kernel, in a new property instead of "opp-microvolt". But the above question still remains, what about other properties that may need magic values in future.
Honestly speaking, I am not sure what's the right thing to do here. I will do whatever you and Rob incline for.
Signature · 1 line
viresh
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 18 lines · Viresh Kumar
Quoted 17 lines · Stephen Boyd
My read of Kevin's comments lead me to think he's saying that a generic 'domain-performance-state' property is worse than putting the numbers directly inside of the opp table with a comment above it. Now that's all fine, but now that we have required-opps binding we sort of have the domain-performance-state property again, but it's a phandle instead of a raw state number.
So we have
required-opps = <&perf_state>;but what was proposed before was
domain-performance-state = <1>;or Kevin's
Quoted 7 lines
Quoted 1 line
opp-table = <100000 1>;His concern was also on what will we do if "frequency" or other OPP properties aren't known tomorrow by the kernel but the firmware? In Qcom case, its just the voltage (corner) today, but it can very well be other properties tomorrow. Are we going to add more platform specific bindings then ?
Yes, we would add more bindings.
Quoted 2 lines
And this is the main reason why I have been
aligned towards using something like this patch.
Once we exceed the number of properties that can fit into the existing voltage and frequency properties we'll only be able to make it work by adding a platform specific property. That's one concern, but it's a future concern so it's not a real problem yet.
If you can clearly describe in the commit text why we shouldn't use platform specific properties it would be helpful.
Quoted 6 lines
If we drop the magic-values idea and hence this patch, then we can either add a "domain-performance-state" property, which will only be used by the power domains or leave it for the platforms to add something like "qcom,corner".
Quoted 8 lines
All we are doing here is putting a voltage (corner) value, unknown to the kernel, in a new property instead of "opp-microvolt". But the above question still remains, what about other properties that may need magic values in future.
Honestly speaking, I am not sure what's the right thing to do here. I will do whatever you and Rob incline for.
Hopefully Rob and Kevin can reply here.
Signature · 2 lines
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
In reply to Viresh KumarQuoted 56 lines · Viresh Kumar
Quoted 37 lines · Rob Herring
Quoted 10 lines · Viresh Kumar
Quoted 8 lines · Rob Herring
Documentation/devicetree/bindings/opp/opp.txt properties. · line 174
Quoted 4 lines · Viresh Kumar
Documentation/devicetree/bindings/opp/opp.txt +4
-0+On some platforms the exact frequency or voltage may be hidden from the OS by +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain +magic values that represent the frequency or voltage in a firmware dependent +way, for example an index of an array in the firmware.I'm still not convinced this is a good idea.
Quoted 3 lines
You were kind-of a few days back :)
lkml.kernel.org/r/CAL_JsqK-qtAaM_Ou5NtxcWR3F_q=8rMPJUm-VqGtKhbtWe5SAQ@mail.gmail.com
Yeah, well that was before Stephen said anything.
Quoted 8 lines
So here is the deal:
- I proposed "domain-performance-state" property for this stuff initially.
- But Kevin didn't like that and proposed reusing "opp-hz" and "opp-microvolt", which we all agreed to multiple times..
- And we are back to the same discussion now and its painful and time killing for all of us.There's bigger issues than where we put magic values as I raised in the other patch.
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TBH, I don't have too strong preferences about any of the suggestions you guys have and I need you guys to tell me what binding changes to do here and I will do that.
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If you have firmware
partially managing things, then I think we should have platform specific bindings or drivers.Quoted 8 lines
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What about the initial idea then, like "performance-state" for the power domains ? All platforms will anyway replicate that binding only.
I don't really know. I don't really care either. I'll probably go along with what everyone agrees to, but the only one I see any agreement from is Ulf. Also, it is pretty vague as to what platforms will use this. You claimed you can support QCom scenarios, but there's really no evidence that that is true.
Well, I sent out the code few days back based on these bindings and everyone can see how these bindings will get used now.
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What I don't want to see is this
merged and then we need something more yet again in a few months for another platform.Sure, I get your concerns.
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So what we need now is:
- Stephen to start responding and clarify all the doubts he had as being silent isn't helping.
- Or Rajendra to post patches which can prove that this is usable. The last time I had a chat with him, he confirmed that he will post patches after 4.15-rc1 and he should have posted them by now, but he didn't :(
I would want to reiterate what I have been saying for a while, that for these patches to be usable on any qualcomm platform completely we need support to associate multiple power-domains to a single device which is missing today.
The last time this came up during a discussion at connect, I believe the understanding was to get this (performance state support) merged *after* we decide how to support multiple powerdomains per device.
What I have been testing with these patches is to move a single user (MMC, which BTW does not have to put requests on multiple powerdomains) to use this solution on a db820c (msm8996) device. Getting this merged now can open up issues for other devices (which can't move to this solution) since MMC alone would put requests to pull a *common* rail up/down while others can't.
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Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Quoted 3 lines · Rajendra Nayak
I would want to reiterate what I have been saying for a while, that for these patches to be usable on any qualcomm platform completely we need support to associate multiple power-domains to a single device which is missing today.
Sure, but I had the understanding based on our last communication that you are going to go with partial support for now and multiple domain thing will be done later on.
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What I have been testing with these patches is to move a single user (MMC, which BTW does not have to put requests on multiple powerdomains) to use this solution on a db820c (msm8996) device.
Right.
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Getting this merged now can open up issues for other devices (which can't move to this solution) since MMC alone would put requests to pull a *common* rail up/down while others can't.
Even on that I thought that you will artificially vote for a high requirement for those devices from some platform code initially, and remove that code once all the device drivers (you need) are updated to post their own requirements.
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Quoted 29 lines · Viresh Kumar
Hi,
Now that the performance state of PM domains are supported by the kernel (merged in linux-next), I am trying once again to define the bindings which we dropped until the code is merged first.
Summary:
Power-domains can also have their active states and this patchset enhances the OPP binding to define those.
The power domains can use the OPP bindings mostly as is. Though there are some changes required to support special cases:
- Allow "operating-points-v2" to contain multiple phandles for power domain providers providing multiple domains.
- A new property "required-opp" is added for the devices to specify the minimum required OPP of the master domain or any other type of device.
- Allow some of the OPP properties to accept magic values (firmware dependent) as the OS doesn't know the real freq/voltage values.
V7->V8:
- V7 1/2 divided into two patches. 1/3 is unchanged from V7.
- 2/3 renamed the property from "power-domain-opp" to "required-opp", as suggested by Rob.
- Added Ulf's reviewed-by for 1/3 and 3/3.
Quoted 8 lines
--
vireshViresh Kumar (3):
OPP: Allow OPP table to be used for power-domains
OPP: Introduce "required-opp" propertyOPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
Discussions are still going on for the last commit, though the first two are already Acked by Rob and Ulf and are quite independent of the third one.
Any objections to getting the first two merged for 4.16-rc1 ? I will send them to Rafael on Friday if no one objects.
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