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Diffstat (limited to 'Documentation/devicetree/bindings/arm/vexpress.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/arm/vexpress.txt | 68 |
1 files changed, 67 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/arm/vexpress.txt b/Documentation/devicetree/bindings/arm/vexpress.txt index ec8b50cbb2e8..5d9996b9eabf 100644 --- a/Documentation/devicetree/bindings/arm/vexpress.txt +++ b/Documentation/devicetree/bindings/arm/vexpress.txt @@ -11,6 +11,10 @@ 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"; @@ -45,6 +49,10 @@ Optional properties in the root node: - 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.: @@ -59,6 +67,52 @@ with device_type = "cpu" property for every available core, eg.: }; }; + +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. + +Nodes describing devices controlled by this infrastructure should +point at the bridge device node: +- bridge phandle: + arm,vexpress,config-bridge = <phandle>; +This property can be also defined in a parent node (eg. for a DCC) +and is effective for all children. + + +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 @@ -96,13 +150,16 @@ The tile description must define "ranges", "interrupt-map-mask" and "interrupt-map" properties to translate the motherboard's address and interrupt space into one used by the tile's processor. -Abbreviated example: + +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>; @@ -134,6 +191,15 @@ Abbreviated example: <0x2c000100 0x100>; }; + dcc { + compatible = "simple-bus"; + arm,vexpress,config-bridge = <&v2m_sysreg>; + + osc@0 { + compatible = "arm,vexpress-osc"; + }; + }; + motherboard { /* CS0 is visible at 0x08000000 */ ranges = <0 0 0x08000000 0x04000000>; |