powerpc/fsl: define binding for fsl mpic interrupt controllers
Define the binding for compatible = "fsl,mpic", including the definition of 4-cell interrupt specifiers. The 3rd and 4th cells are needed to define additional types of interrupt source outside the "normal" external and internal interrupts in FSL SoCs. Define error interrupt, IPIs, and PIC timer sources. Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>hifive-unleashed-5.1
Stuart Yoder
Kumar Gala
parent
6820fead71
commit
5205287554
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@ -1,42 +1,211 @@
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* OpenPIC and its interrupt numbers on Freescale's e500/e600 cores
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=====================================================================
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Freescale MPIC Interrupt Controller Node
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Copyright (C) 2010,2011 Freescale Semiconductor Inc.
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=====================================================================
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The OpenPIC specification does not specify which interrupt source has to
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become which interrupt number. This is up to the software implementation
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of the interrupt controller. The only requirement is that every
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interrupt source has to have an unique interrupt number / vector number.
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To accomplish this the current implementation assigns the number zero to
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the first source, the number one to the second source and so on until
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all interrupt sources have their unique number.
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Usually the assigned vector number equals the interrupt number mentioned
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in the documentation for a given core / CPU. This is however not true
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for the e500 cores (MPC85XX CPUs) where the documentation distinguishes
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between internal and external interrupt sources and starts counting at
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zero for both of them.
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The Freescale MPIC interrupt controller is found on all PowerQUICC
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and QorIQ processors and is compatible with the Open PIC. The
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notable difference from Open PIC binding is the addition of 2
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additional cells in the interrupt specifier defining interrupt type
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information.
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So what to write for external interrupt source X or internal interrupt
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source Y into the device tree? Here is an example:
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PROPERTIES
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The memory map for the interrupt controller in the MPC8544[0] shows,
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that the first interrupt source starts at 0x5_0000 (PIC Register Address
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Map-Interrupt Source Configuration Registers). This source becomes the
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number zero therefore:
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External interrupt 0 = interrupt number 0
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External interrupt 1 = interrupt number 1
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External interrupt 2 = interrupt number 2
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...
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Every interrupt number allocates 0x20 bytes register space. So to get
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its number it is sufficient to shift the lower 16bits to right by five.
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So for the external interrupt 10 we have:
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0x0140 >> 5 = 10
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- compatible
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Usage: required
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Value type: <string>
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Definition: Shall include "fsl,mpic". Freescale MPIC
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controllers compatible with this binding have Block
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Revision Registers BRR1 and BRR2 at offset 0x0 and
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0x10 in the MPIC.
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After the external sources, the internal sources follow. The in core I2C
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controller on the MPC8544 for instance has the internal source number
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27. Oo obtain its interrupt number we take the lower 16bits of its memory
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address (0x5_0560) and shift it right:
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0x0560 >> 5 = 43
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- reg
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Usage: required
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Value type: <prop-encoded-array>
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Definition: A standard property. Specifies the physical
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offset and length of the device's registers within the
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CCSR address space.
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Therefore the I2C device node for the MPC8544 CPU has to have the
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interrupt number 43 specified in the device tree.
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- interrupt-controller
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Usage: required
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Value type: <empty>
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Definition: Specifies that this node is an interrupt
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controller
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[0] MPC8544E PowerQUICCTM III, Integrated Host Processor Family Reference Manual
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MPC8544ERM Rev. 1 10/2007
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- #interrupt-cells
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Usage: required
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Value type: <u32>
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Definition: Shall be 2 or 4. A value of 2 means that interrupt
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specifiers do not contain the interrupt-type or type-specific
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information cells.
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- #address-cells
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Usage: required
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Value type: <u32>
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Definition: Shall be 0.
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- pic-no-reset
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Usage: optional
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Value type: <empty>
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Definition: The presence of this property specifies that the
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MPIC must not be reset by the client program, and that
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the boot program has initialized all interrupt source
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configuration registers to a sane state-- masked or
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directed at other cores. This ensures that the client
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program will not receive interrupts for sources not belonging
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to the client. The presence of this property also mandates
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that any initialization related to interrupt sources shall
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be limited to sources explicitly referenced in the device tree.
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INTERRUPT SPECIFIER DEFINITION
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Interrupt specifiers consists of 4 cells encoded as
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follows:
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<1st-cell> interrupt-number
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Identifies the interrupt source. The meaning
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depends on the type of interrupt.
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Note: If the interrupt-type cell is undefined
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(i.e. #interrupt-cells = 2), this cell
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should be interpreted the same as for
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interrupt-type 0-- i.e. an external or
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normal SoC device interrupt.
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<2nd-cell> level-sense information, encoded as follows:
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0 = low-to-high edge triggered
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1 = active low level-sensitive
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2 = active high level-sensitive
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3 = high-to-low edge triggered
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<3rd-cell> interrupt-type
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The following types are supported:
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0 = external or normal SoC device interrupt
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The interrupt-number cell contains
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the SoC device interrupt number. The
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type-specific cell is undefined. The
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interrupt-number is derived from the
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MPIC a block of registers referred to as
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the "Interrupt Source Configuration Registers".
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Each source has 32-bytes of registers
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(vector/priority and destination) in this
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region. So interrupt 0 is at offset 0x0,
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interrupt 1 is at offset 0x20, and so on.
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1 = error interrupt
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The interrupt-number cell contains
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the SoC device interrupt number for
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the error interrupt. The type-specific
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cell identifies the specific error
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interrupt number.
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2 = MPIC inter-processor interrupt (IPI)
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The interrupt-number cell identifies
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the MPIC IPI number. The type-specific
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cell is undefined.
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3 = MPIC timer interrupt
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The interrupt-number cell identifies
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the MPIC timer number. The type-specific
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cell is undefined.
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<4th-cell> type-specific information
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The type-specific cell is encoded as follows:
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- For interrupt-type 1 (error interrupt),
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the type-specific cell contains the
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bit number of the error interrupt in the
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Error Interrupt Summary Register.
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EXAMPLE 1
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/*
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* mpic interrupt controller with 4 cells per specifier
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*/
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mpic: pic@40000 {
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compatible = "fsl,mpic";
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interrupt-controller;
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#interrupt-cells = <4>;
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#address-cells = <0>;
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reg = <0x40000 0x40000>;
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};
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EXAMPLE 2
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/*
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* The MPC8544 I2C controller node has an internal
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* interrupt number of 27. As per the reference manual
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* this corresponds to interrupt source configuration
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* registers at 0x5_0560.
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*
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* The interrupt source configuration registers begin
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* at 0x5_0000.
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*
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* To compute the interrupt specifier interrupt number
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*
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* 0x560 >> 5 = 43
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*
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* The interrupt source configuration registers begin
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* at 0x5_0000, and so the i2c vector/priority registers
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* are at 0x5_0560.
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*/
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i2c@3000 {
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#address-cells = <1>;
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#size-cells = <0>;
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cell-index = <0>;
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compatible = "fsl-i2c";
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reg = <0x3000 0x100>;
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interrupts = <43 2>;
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interrupt-parent = <&mpic>;
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dfsrr;
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};
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EXAMPLE 3
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/*
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* Definition of a node defining the 4
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* MPIC IPI interrupts. Note the interrupt
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* type of 2.
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*/
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ipi@410a0 {
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compatible = "fsl,mpic-ipi";
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reg = <0x40040 0x10>;
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interrupts = <0 0 2 0
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1 0 2 0
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2 0 2 0
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3 0 2 0>;
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};
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EXAMPLE 4
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/*
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* Definition of a node defining the MPIC
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* global timers. Note the interrupt
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* type of 3.
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*/
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timer0: timer@41100 {
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compatible = "fsl,mpic-global-timer";
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reg = <0x41100 0x100>;
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interrupts = <0 0 3 0
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1 0 3 0
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2 0 3 0
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3 0 3 0>;
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};
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EXAMPLE 5
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/*
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* Definition of an error interrupt (interupt type 1).
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* SoC interrupt number is 16 and the specific error
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* interrupt bit in the error interrupt summary register
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* is 23.
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*/
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memory-controller@8000 {
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compatible = "fsl,p4080-memory-controller";
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reg = <0x8000 0x1000>;
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interrupts = <16 2 1 23>;
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};
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