7f2e858408
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 <ivan.gorinov@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Rob Herring <robh@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Frank Rowand <frowand.list@gmail.com> Link: https://lkml.kernel.org/r/4b1a471a56ac0ebd7510f4759afce9104595d6da.1521753738.git.ivan.gorinov@intel.com
58 lines
1.4 KiB
Plaintext
58 lines
1.4 KiB
Plaintext
CE4100 Device Tree Bindings
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---------------------------
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The CE4100 SoC uses for in core peripherals the following compatible
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format: <vendor>,<chip>-<device>.
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Many of the "generic" devices like HPET or IO APIC have the ce4100
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name in their compatible property because they first appeared in this
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SoC.
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The CPU nodes
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-------------
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cpus {
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#address-cells = <1>;
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#size-cells = <0>;
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cpu@0 {
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device_type = "cpu";
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compatible = "intel,ce4100";
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reg = <0x00>;
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};
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cpu@2 {
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device_type = "cpu";
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compatible = "intel,ce4100";
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reg = <0x02>;
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};
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};
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A "cpu" node describes one logical processor (hardware thread).
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Required properties:
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- device_type
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Device type, must be "cpu".
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- reg
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Local APIC ID, the unique number assigned to each processor by
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system hardware.
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The SoC node
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------------
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This node describes the in-core peripherals. Required property:
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compatible = "intel,ce4100-cp";
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The PCI node
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------------
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This node describes the PCI bus on the SoC. Its property should be
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compatible = "intel,ce4100-pci", "pci";
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If the OS is using the IO-APIC for interrupt routing then the reported
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interrupt numbers for devices is no longer true. In order to obtain the
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correct interrupt number, the child node which represents the device has
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to contain the interrupt property. Besides the interrupt property it has
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to contain at least the reg property containing the PCI bus address and
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compatible property according to "PCI Bus Binding Revision 2.1".
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