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authorSascha Hauer <s.hauer@pengutronix.de>2019-08-19 08:56:20 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2019-08-19 08:56:20 +0200
commit6940ba22c66ac1c713500027bf5f6832442a1410 (patch)
treea460f01b9807e1c17206a40dbc94b6f54167cf29 /dts/Bindings/arm/psci.yaml
parente66a790177410d7433e6672d97bb0b54455ba669 (diff)
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dts: update to v5.3-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/psci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Power State Coordination Interface (PSCI)
+
+maintainers:
+ - Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+
+description: |+
+ Firmware implementing the PSCI functions described in ARM document number
+ ARM DEN 0022A ("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.
+
+ 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:
+
+ r0 => 32-bit Function ID / return value
+ {r1 - r3} => Parameters
+
+ Note that the immediate field of the trapping instruction must be set
+ to #0.
+
+ [2] Power State Coordination Interface (PSCI) specification
+ http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
+
+properties:
+ compatible:
+ oneOf:
+ - description:
+ For implementations complying to PSCI versions prior to 0.2.
+ const: arm,psci
+
+ - description:
+ For implementations complying to PSCI 0.2.
+ const: arm,psci-0.2
+
+ - description:
+ For implementations complying to PSCI 0.2.
+ Function IDs are not required and should be ignored by an OS with
+ PSCI 0.2 support, but are permitted to be present for compatibility
+ with existing software when "arm,psci" is later in the compatible
+ list.
+ items:
+ - const: arm,psci-0.2
+ - const: arm,psci
+
+ - description:
+ For implementations complying to PSCI 1.0.
+ const: arm,psci-1.0
+
+ - description:
+ For implementations complying to PSCI 1.0.
+ PSCI 1.0 is backward compatible with PSCI 0.2 with minor
+ specification updates, as defined in the PSCI specification[2].
+ items:
+ - const: arm,psci-1.0
+ - const: arm,psci-0.2
+
+ method:
+ description: The method of calling the PSCI firmware.
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/string-array
+ - enum:
+ # SMC #0, with the register assignments specified in this binding.
+ - smc
+ # HVC #0, with the register assignments specified in this binding.
+ - hvc
+
+ cpu_suspend:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: Function ID for CPU_SUSPEND operation
+
+ cpu_off:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: Function ID for CPU_OFF operation
+
+ cpu_on:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: Function ID for CPU_ON operation
+
+ migrate:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: Function ID for MIGRATE operation
+
+ arm,psci-suspend-param:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ power_state parameter to pass to the PSCI suspend call.
+
+ Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie
+ idle state nodes with entry-method property is set to "psci", as per
+ bindings in [1]) must specify this property.
+
+ [1] Kernel documentation - ARM idle states bindings
+ Documentation/devicetree/bindings/arm/idle-states.txt
+
+
+required:
+ - compatible
+ - method
+
+allOf:
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: arm,psci
+ then:
+ required:
+ - cpu_off
+ - cpu_on
+
+examples:
+ - |+
+
+ // Case 1: PSCI v0.1 only.
+
+ psci {
+ compatible = "arm,psci";
+ method = "smc";
+ cpu_suspend = <0x95c10000>;
+ cpu_off = <0x95c10001>;
+ cpu_on = <0x95c10002>;
+ migrate = <0x95c10003>;
+ };
+
+ - |+
+
+ // Case 2: PSCI v0.2 only
+
+ psci {
+ compatible = "arm,psci-0.2";
+ method = "smc";
+ };
+
+
+ - |+
+
+ // Case 3: PSCI v0.2 and PSCI v0.1.
+
+ /*
+ * A DTB may provide IDs for use by kernels without PSCI 0.2 support,
+ * enabling firmware and hypervisors to support existing and new kernels.
+ * These IDs will be ignored by kernels with PSCI 0.2 support, which will
+ * use the standard PSCI 0.2 IDs exclusively.
+ */
+
+ psci {
+ compatible = "arm,psci-0.2", "arm,psci";
+ method = "hvc";
+
+ cpu_on = <0x95c10002>;
+ cpu_off = <0x95c10001>;
+ };
+...