From 7f2e85840871f199057e65232ebde846192ed989 Mon Sep 17 00:00:00 2001 From: Ivan Gorinov Date: Thu, 22 Mar 2018 14:35:33 -0700 Subject: [PATCH] of/Documentation: Specify local APIC ID in "reg" Use the "reg" property to specify the processor's local APIC ID instead of setting it to the CPU node index in Device Tree. Local APIC ID is assigned by hardware and visible in the APIC ID register. Some processor models allow APIC ID to be changed by software, but CPUID instruction executed with %eax = 0x0b always returns the initial ID in %edx. Local APIC ID does not match the node index in many systems. Signed-off-by: Ivan Gorinov Signed-off-by: Thomas Gleixner Reviewed-by: Andy Shevchenko Reviewed-by: Rob Herring Cc: Mark Rutland Cc: Rob Herring Cc: Frank Rowand Link: https://lkml.kernel.org/r/4b1a471a56ac0ebd7510f4759afce9104595d6da.1521753738.git.ivan.gorinov@intel.com --- .../devicetree/bindings/x86/ce4100.txt | 37 ++++++++++++++----- 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/Documentation/devicetree/bindings/x86/ce4100.txt b/Documentation/devicetree/bindings/x86/ce4100.txt index b49ae593a60b..cd1221bfb539 100644 --- a/Documentation/devicetree/bindings/x86/ce4100.txt +++ b/Documentation/devicetree/bindings/x86/ce4100.txt @@ -7,17 +7,36 @@ Many of the "generic" devices like HPET or IO APIC have the ce4100 name in their compatible property because they first appeared in this SoC. -The CPU node ------------- - cpu@0 { - device_type = "cpu"; - compatible = "intel,ce4100"; - reg = <0>; - lapic = <&lapic0>; +The CPU nodes +------------- + + cpus { + #address-cells = <1>; + #size-cells = <0>; + + cpu@0 { + device_type = "cpu"; + compatible = "intel,ce4100"; + reg = <0x00>; + }; + + cpu@2 { + device_type = "cpu"; + compatible = "intel,ce4100"; + reg = <0x02>; + }; }; -The reg property describes the CPU number. The lapic property points to -the local APIC timer. +A "cpu" node describes one logical processor (hardware thread). + +Required properties: + +- device_type + Device type, must be "cpu". + +- reg + Local APIC ID, the unique number assigned to each processor by + system hardware. The SoC node ------------ -- GitLab