* [PATCH v3] dt: update PSCI binding documentation for v0.2
@ 2013-08-27 0:50 Rob Herring
2013-09-03 9:52 ` Mark Rutland
0 siblings, 1 reply; 3+ messages in thread
From: Rob Herring @ 2013-08-27 0:50 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Mark Rutland, devicetree, Ian Campbell, Stefano Stabellini,
Marc Zyngier, Rob Herring, Matt Sealey, Dave Martin,
Christoffer Dall, Charles Garcia-Tobin
From: Rob Herring <rob.herring@calxeda.com>
The PSCI spec from ARM has been updated to 0.2 version. Update the
binding document to reflect the spec changes. For the binding, the
major changes are the addition of psci_version, affinity_info,
migrate_info_type, migrate_info_up_cpu, system_reset and system_off
functions. The recommended function ID numbering has also changed.
This update also defines 32 and 64 bit calling conventions. The calling
convention is defined on a per function ID basis.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>,
Cc: Charles Garcia-Tobin <Charles.Garcia-Tobin@arm.com>
Cc: Matt Sealey <neko@bakuhatsu.net>
Cc: devicetree@vger.kernel.org
---
v3: This version implements Mark's suggested binding with -32 and -64 suffixes.
Documentation/devicetree/bindings/arm/psci.txt | 62 +++++++++++++++++++-------
1 file changed, 46 insertions(+), 16 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt
index 433afe9..209bb04 100644
--- a/Documentation/devicetree/bindings/arm/psci.txt
+++ b/Documentation/devicetree/bindings/arm/psci.txt
@@ -1,16 +1,17 @@
* Power State Coordination Interface (PSCI)
Firmware implementing the PSCI functions described in ARM document number
-ARM DEN 0022A ("Power State Coordination Interface System Software on ARM
+ARM DEN 0022B ("Power State Coordination Interface System Software on ARM
processors") can be used by Linux to initiate various CPU-centric power
operations.
-Issue A of the specification describes functions for CPU suspend, hotplug
-and migration of secure software.
+Issue B of the specification describes functions for CPU suspend, hotplug,
+migration of secure software, and system level reset and powerdown.
Functions are invoked by trapping to the privilege level of the PSCI
firmware (specified as part of the binding below) and passing arguments
-in a manner similar to that specified by AAPCS:
+as defined in ARM document "SMC Calling Convention" (ARM DEN 0028) in a manner
+similar to that specified by AAPCS:
r0 => 32-bit Function ID / return value
{r1 - r3} => Parameters
@@ -21,10 +22,10 @@ to #0.
Main node required properties:
- - compatible : Must be "arm,psci"
+ - compatible : Must contain "arm,psci-0.2" or "arm,psci"
- - method : The method of calling the PSCI firmware. Permitted
- values are:
+ - method : The method defines the calling convention for the PSCI
+ firmware. Permitted values are:
"smc" : SMC #0, with the register assignments specified
in this binding.
@@ -32,24 +33,53 @@ Main node required properties:
"hvc" : HVC #0, with the register assignments specified
in this binding.
+ - psci_version : Function ID for PSCI_VERSION operation. Required for
+ "arm,psci-0.2" compatible version or later.
+
Main node optional properties:
- - cpu_suspend : Function ID for CPU_SUSPEND operation
+ - cpu_suspend[-<32|64] : Function ID for CPU_SUSPEND operation
+
+ - cpu_off : Function ID for CPU_OFF operation
+
+ - cpu_on[-<32|64] : Function ID for CPU_ON operation
+
+ - affinity_info[-<32|64] : Function ID for AFFINITY_INFO operation
- - cpu_off : Function ID for CPU_OFF operation
+ - migrate[-<32|64] : Function ID for MIGRATE operation
- - cpu_on : Function ID for CPU_ON operation
+ - migrate_info_type : Function ID for MIGRATE_INFO_TYPE operation
- - migrate : Function ID for MIGRATE operation
+ - migrate_info_up_cpu[-<32|64] : Function ID for MIGRATE_INFO_UP_CPU operation
+ - system_reset : Function ID for SYSTEM_RESET operation
+
+ - system_off : Function ID for SYSTEM_OFF operation
+
+Some function IDs support 32-bit and 64-bit calling conventions. If no size is
+specified, then the 32-bit calling convention is used. Therefore, all function
+IDs for 64-bit calling convention are required to have "-64" suffix. Use of the
+"-32" suffix is recommended, but not required for backwards compatibility.
Example:
psci {
- compatible = "arm,psci";
+ compatible = "arm,psci-0.2";
method = "smc";
- cpu_suspend = <0x95c10000>;
- cpu_off = <0x95c10001>;
- cpu_on = <0x95c10002>;
- migrate = <0x95c10003>;
+ psci_version = <0x84000000>;
+ cpu_suspend-32 = <0x84000001>;
+ cpu_suspend-64 = <0xc4000001>;
+ cpu_off = <0x84000002>;
+ cpu_on-32 = <0x84000003>;
+ cpu_on-64 = <0xc4000003>;
+ affinity_info-32 = <0x84000004>;
+ affinity_info-64 = <0xc4000004>;
+ migrate-32 = <0x84000005>;
+ migrate-64 = <0xc4000005>;
+ migrate_info_type = <0x84000006>;
+ migrate_info_up_cpu-32 = <0x84000007>;
+ migrate_info_up_cpu-64 = <0xc4000007>;
+ system_off = <0x84000008>;
+ system_reset = <0x84000009>;
};
+
--
1.8.1.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3] dt: update PSCI binding documentation for v0.2
2013-08-27 0:50 [PATCH v3] dt: update PSCI binding documentation for v0.2 Rob Herring
@ 2013-09-03 9:52 ` Mark Rutland
[not found] ` <20130903095235.GD18206-NuALmloUBlrZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Mark Rutland @ 2013-09-03 9:52 UTC (permalink / raw)
To: Rob Herring
Cc: devicetree@vger.kernel.org, Ian Campbell, Stefano Stabellini,
Marc Zyngier, rob.herring@calxeda.com, Christoffer Dall,
Matt Sealey, Dave P Martin, linux-arm-kernel@lists.infradead.org,
Charles Garcia-Tobin
On Tue, Aug 27, 2013 at 01:50:33AM +0100, Rob Herring wrote:
> From: Rob Herring <rob.herring@calxeda.com>
Hi Rob,
Sorry for the delay on reviewing this.
>
> The PSCI spec from ARM has been updated to 0.2 version. Update the
> binding document to reflect the spec changes. For the binding, the
> major changes are the addition of psci_version, affinity_info,
> migrate_info_type, migrate_info_up_cpu, system_reset and system_off
> functions. The recommended function ID numbering has also changed.
>
> This update also defines 32 and 64 bit calling conventions. The calling
> convention is defined on a per function ID basis.
>
> Signed-off-by: Rob Herring <rob.herring@calxeda.com>
> Cc: Dave Martin <Dave.Martin@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Ian Campbell <Ian.Campbell@citrix.com>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: Marc Zyngier <Marc.Zyngier@arm.com>
> Cc: Christoffer Dall <christoffer.dall@linaro.org>,
> Cc: Charles Garcia-Tobin <Charles.Garcia-Tobin@arm.com>
> Cc: Matt Sealey <neko@bakuhatsu.net>
> Cc: devicetree@vger.kernel.org
> ---
> v3: This version implements Mark's suggested binding with -32 and -64 suffixes.
>
> Documentation/devicetree/bindings/arm/psci.txt | 62 +++++++++++++++++++-------
> 1 file changed, 46 insertions(+), 16 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt
> index 433afe9..209bb04 100644
> --- a/Documentation/devicetree/bindings/arm/psci.txt
> +++ b/Documentation/devicetree/bindings/arm/psci.txt
> @@ -1,16 +1,17 @@
> * Power State Coordination Interface (PSCI)
>
> Firmware implementing the PSCI functions described in ARM document number
> -ARM DEN 0022A ("Power State Coordination Interface System Software on ARM
> +ARM DEN 0022B ("Power State Coordination Interface System Software on ARM
> processors") can be used by Linux to initiate various CPU-centric power
> operations.
>
> -Issue A of the specification describes functions for CPU suspend, hotplug
> -and migration of secure software.
> +Issue B of the specification describes functions for CPU suspend, hotplug,
> +migration of secure software, and system level reset and powerdown.
>
> Functions are invoked by trapping to the privilege level of the PSCI
> firmware (specified as part of the binding below) and passing arguments
> -in a manner similar to that specified by AAPCS:
> +as defined in ARM document "SMC Calling Convention" (ARM DEN 0028) in a manner
> +similar to that specified by AAPCS:
>
> r0 => 32-bit Function ID / return value
> {r1 - r3} => Parameters
> @@ -21,10 +22,10 @@ to #0.
>
> Main node required properties:
>
> - - compatible : Must be "arm,psci"
> + - compatible : Must contain "arm,psci-0.2" or "arm,psci"
>
> - - method : The method of calling the PSCI firmware. Permitted
> - values are:
> + - method : The method defines the calling convention for the PSCI
> + firmware. Permitted values are:
>
> "smc" : SMC #0, with the register assignments specified
> in this binding.
> @@ -32,24 +33,53 @@ Main node required properties:
> "hvc" : HVC #0, with the register assignments specified
> in this binding.
>
> + - psci_version : Function ID for PSCI_VERSION operation. Required for
> + "arm,psci-0.2" compatible version or later.
> +
While this seems sensible, I'm not sure that this needs to be mandatory.
> Main node optional properties:
>
> - - cpu_suspend : Function ID for CPU_SUSPEND operation
> + - cpu_suspend[-<32|64] : Function ID for CPU_SUSPEND operation
> +
> + - cpu_off : Function ID for CPU_OFF operation
> +
> + - cpu_on[-<32|64] : Function ID for CPU_ON operation
> +
> + - affinity_info[-<32|64] : Function ID for AFFINITY_INFO operation
>
> - - cpu_off : Function ID for CPU_OFF operation
> + - migrate[-<32|64] : Function ID for MIGRATE operation
>
> - - cpu_on : Function ID for CPU_ON operation
> + - migrate_info_type : Function ID for MIGRATE_INFO_TYPE operation
>
> - - migrate : Function ID for MIGRATE operation
> + - migrate_info_up_cpu[-<32|64] : Function ID for MIGRATE_INFO_UP_CPU operation
>
> + - system_reset : Function ID for SYSTEM_RESET operation
> +
> + - system_off : Function ID for SYSTEM_OFF operation
> +
> +Some function IDs support 32-bit and 64-bit calling conventions. If no size is
> +specified, then the 32-bit calling convention is used. Therefore, all function
> +IDs for 64-bit calling convention are required to have "-64" suffix. Use of the
> +"-32" suffix is recommended, but not required for backwards compatibility.
I don't think we can say that non suffixed IDs mean use the 32-bit
calling convention -- the arm64 PSCI code uses 64-bit parameters at the
moment for non-suffixed IDs.
I think if we say that callers should use their native register width
calling convention for non-suffixed IDs, it's compatible with all PSCI
implementations using DT in the wild currently. Implementations on v7
don't have AArch64 state, so can't ever use the 64-bit convention, and
existing 64-bit implementations like KVM has are implemented at EL2, so
the guest is stuck at a particular register width.
Given that, how about the below?
Some functions have have separate IDs for 32-bit and 64-bit calling
conventions. These separate function IDs are described with function
names with "-64" and "-32" suffixes (e.g. cpu_on-64). Where a function
name does not have a suffix, the ID may be used with either calling
convention depending on the CPU state -- AArch32 callers should use the
32-bit calling convention, and AArch64 callers should use the 64-bit
calling convention.
Thanks,
Mark.
>
> Example:
>
> psci {
> - compatible = "arm,psci";
> + compatible = "arm,psci-0.2";
> method = "smc";
> - cpu_suspend = <0x95c10000>;
> - cpu_off = <0x95c10001>;
> - cpu_on = <0x95c10002>;
> - migrate = <0x95c10003>;
> + psci_version = <0x84000000>;
> + cpu_suspend-32 = <0x84000001>;
> + cpu_suspend-64 = <0xc4000001>;
> + cpu_off = <0x84000002>;
> + cpu_on-32 = <0x84000003>;
> + cpu_on-64 = <0xc4000003>;
> + affinity_info-32 = <0x84000004>;
> + affinity_info-64 = <0xc4000004>;
> + migrate-32 = <0x84000005>;
> + migrate-64 = <0xc4000005>;
> + migrate_info_type = <0x84000006>;
> + migrate_info_up_cpu-32 = <0x84000007>;
> + migrate_info_up_cpu-64 = <0xc4000007>;
> + system_off = <0x84000008>;
> + system_reset = <0x84000009>;
> };
> +
> --
> 1.8.1.2
>
>
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2013-08-27 0:50 [PATCH v3] dt: update PSCI binding documentation for v0.2 Rob Herring
2013-09-03 9:52 ` Mark Rutland
[not found] ` <20130903095235.GD18206-NuALmloUBlrZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org>
2013-09-13 19:23 ` Rob Herring
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