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[v4,2/6] Documentation: devicetree: psci: define CPU suspend parameter

Message ID 1402503520-8611-3-git-send-email-lorenzo.pieralisi@arm.com
State New
Headers show

Commit Message

Lorenzo Pieralisi June 11, 2014, 4:18 p.m. UTC 
OS layers built on top of PSCI to enter low-power states require the
power_state parameter to be passed to the PSCI CPU suspend method.

This parameter is specific to a power state and platform specific,
therefore must be provided by firmware to the OS in order to enable
proper call sequence.

This patch adds a property in the PSCI bindings that describes how
the CPU suspend power_state parameter should be defined in DT in
all device nodes that rely on PSCI CPU suspend method usage.

Reviewed-by: Sebastian Capella <sebcape@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 Documentation/devicetree/bindings/arm/psci.txt | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
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Patch

diff --git a/Documentation/devicetree/bindings/arm/psci.txt b/Documentation/devicetree/bindings/arm/psci.txt
index b4a58f3..fae3eed 100644
--- a/Documentation/devicetree/bindings/arm/psci.txt
+++ b/Documentation/devicetree/bindings/arm/psci.txt
@@ -50,6 +50,14 @@  Main node optional properties:
 
  - migrate       : Function ID for MIGRATE operation
 
+Device tree nodes that require usage of PSCI CPU_SUSPEND function (ie idle
+states bindings[1]) must specify the following properties:
+
+- entry-method-param
+		Usage: Required for idle states bindings [1].
+		Value type: <u32>
+		Definition: power_state parameter to pass to the PSCI
+			    suspend call.
 
 Example:
 
@@ -64,7 +72,6 @@  Case 1: PSCI v0.1 only.
 		migrate		= <0x95c10003>;
 	};
 
-
 Case 2: PSCI v0.2 only
 
 	psci {
@@ -88,3 +95,6 @@  Case 3: PSCI v0.2 and PSCI v0.1.
 
 		...
 	};
+
+[1] Kernel documentation - ARM idle states bindings
+    Documentation/devicetree/bindings/arm/idle-states.txt