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diff --git a/Documentation/devicetree/bindings/arm/vexpress.txt b/Documentation/devicetree/bindings/arm/vexpress.txt new file mode 100644 index 000000000..39844cd0b --- /dev/null +++ b/Documentation/devicetree/bindings/arm/vexpress.txt @@ -0,0 +1,229 @@ +ARM Versatile Express boards family +----------------------------------- + +ARM's Versatile Express platform consists of a motherboard and one +or more daughterboards (tiles). The motherboard provides a set of +peripherals. Processor and RAM "live" on the tiles. + +The motherboard and each core tile should be described by a separate +Device Tree source file, with the tile's description including +the motherboard file using a /include/ directive. As the motherboard +can be initialized in one of two different configurations ("memory +maps"), care must be taken to include the correct one. + + +Root node +--------- + +Required properties in the root node: +- compatible value: + compatible = "arm,vexpress,<model>", "arm,vexpress"; + where <model> is the full tile model name (as used in the tile's + Technical Reference Manual), eg.: + - for Coretile Express A5x2 (V2P-CA5s): + compatible = "arm,vexpress,v2p-ca5s", "arm,vexpress"; + - for Coretile Express A9x4 (V2P-CA9): + compatible = "arm,vexpress,v2p-ca9", "arm,vexpress"; + If a tile comes in several variants or can be used in more then one + configuration, the compatible value should be: + compatible = "arm,vexpress,<model>,<variant>", \ + "arm,vexpress,<model>", "arm,vexpress"; + eg: + - Coretile Express A15x2 (V2P-CA15) with Tech Chip 1: + compatible = "arm,vexpress,v2p-ca15,tc1", \ + "arm,vexpress,v2p-ca15", "arm,vexpress"; + - LogicTile Express 13MG (V2F-2XV6) running Cortex-A7 (3 cores) SMM: + compatible = "arm,vexpress,v2f-2xv6,ca7x3", \ + "arm,vexpress,v2f-2xv6", "arm,vexpress"; + +Optional properties in the root node: +- tile model name (use name from the tile's Technical Reference + Manual, eg. "V2P-CA5s") + model = "<model>"; +- tile's HBI number (unique ARM's board model ID, visible on the + PCB's silkscreen) in hexadecimal transcription: + arm,hbi = <0xhbi> + eg: + - for Coretile Express A5x2 (V2P-CA5s) HBI-0191: + arm,hbi = <0x191>; + - Coretile Express A9x4 (V2P-CA9) HBI-0225: + arm,hbi = <0x225>; + + +CPU nodes +--------- + +Top-level standard "cpus" node is required. It must contain a node +with device_type = "cpu" property for every available core, eg.: + + cpus { + #address-cells = <1>; + #size-cells = <0>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a5"; + reg = <0>; + }; + }; + + +Configuration infrastructure +---------------------------- + +The platform has an elaborated configuration system, consisting of +microcontrollers residing on the mother- and daughterboards known +as Motherboard/Daughterboard Configuration Controller (MCC and DCC). +The controllers are responsible for the platform initialization +(reset generation, flash programming, FPGA bitfiles loading etc.) +but also control clock generators, voltage regulators, gather +environmental data like temperature, power consumption etc. Even +the video output switch (FPGA) is controlled that way. + +The controllers are not mapped into normal memory address space +and must be accessed through bridges - other devices capable +of generating transactions on the configuration bus. + +The nodes describing configuration controllers must define +the following properties: +- compatible value: + compatible = "arm,vexpress,config-bus"; +- bridge phandle: + arm,vexpress,config-bridge = <phandle>; +and children describing available functions. + + +Platform topology +----------------- + +As Versatile Express can be configured in number of physically +different setups, the device tree should describe platform topology. +Root node and main motherboard node must define the following +property, describing physical location of the children nodes: +- site number: + arm,vexpress,site = <number>; + where 0 means motherboard, 1 or 2 are daugtherboard sites, + 0xf means "master" site (site containing main CPU tile) +- when daughterboards are stacked on one site, their position + in the stack be be described with: + arm,vexpress,position = <number>; +- when describing tiles consisting more than one DCC, its number + can be described with: + arm,vexpress,dcc = <number>; + +Any of the numbers above defaults to zero if not defined in +the node or any of its parent. + + +Motherboard +----------- + +The motherboard description file provides a single "motherboard" node +using 2 address cells corresponding to the Static Memory Bus used +between the motherboard and the tile. The first cell defines the Chip +Select (CS) line number, the second cell address offset within the CS. +All interrupt lines between the motherboard and the tile are active +high and are described using single cell. + +Optional properties of the "motherboard" node: +- motherboard's memory map variant: + arm,v2m-memory-map = "<name>"; + where name is one of: + - "rs1" - for RS1 map (i.a. peripherals on CS3); this map is also + referred to as "ARM Cortex-A Series memory map": + arm,v2m-memory-map = "rs1"; + When this property is missing, the motherboard is using the original + memory map (also known as the "Legacy memory map", primarily used + with the original CoreTile Express A9x4) with peripherals on CS7. + +Motherboard .dtsi files provide a set of labelled peripherals that +can be used to obtain required phandle in the tile's "aliases" node: +- UARTs, note that the numbers correspond to the physical connectors + on the motherboard's back panel: + v2m_serial0, v2m_serial1, v2m_serial2 and v2m_serial3 +- I2C controllers: + v2m_i2c_dvi and v2m_i2c_pcie +- SP804 timers: + v2m_timer01 and v2m_timer23 + +The tile description should define a "smb" node, describing the +Static Memory Bus between the tile and motherboard. It must define +the following properties: +- "simple-bus" compatible value (to ensure creation of the children) + compatible = "simple-bus"; +- mapping of the SMB CS/offset addresses into main address space: + #address-cells = <2>; + #size-cells = <1>; + ranges = <...>; +- interrupts mapping: + #interrupt-cells = <1>; + interrupt-map-mask = <0 0 63>; + interrupt-map = <...>; + + +Example of a VE tile description (simplified) +--------------------------------------------- + +/dts-v1/; + +/ { + model = "V2P-CA5s"; + arm,hbi = <0x225>; + arm,vexpress,site = <0xf>; + compatible = "arm,vexpress-v2p-ca5s", "arm,vexpress"; + interrupt-parent = <&gic>; + #address-cells = <1>; + #size-cells = <1>; + + chosen { }; + + aliases { + serial0 = &v2m_serial0; + }; + + cpus { + #address-cells = <1>; + #size-cells = <0>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a5"; + reg = <0>; + }; + }; + + gic: interrupt-controller@2c001000 { + compatible = "arm,cortex-a9-gic"; + #interrupt-cells = <3>; + #address-cells = <0>; + interrupt-controller; + reg = <0x2c001000 0x1000>, + <0x2c000100 0x100>; + }; + + dcc { + compatible = "arm,vexpress,config-bus"; + arm,vexpress,config-bridge = <&v2m_sysreg>; + + osc@0 { + compatible = "arm,vexpress-osc"; + }; + }; + + smb { + compatible = "simple-bus"; + + #address-cells = <2>; + #size-cells = <1>; + /* CS0 is visible at 0x08000000 */ + ranges = <0 0 0x08000000 0x04000000>; + + #interrupt-cells = <1>; + interrupt-map-mask = <0 0 63>; + /* Active high IRQ 0 is connected to GIC's SPI0 */ + interrupt-map = <0 0 0 &gic 0 0 4>; + + /include/ "vexpress-v2m-rs1.dtsi" + }; +}; + |