Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt

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System
Linux kernel
Corpus path
Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt
Extension
.txt
Size
7187 bytes
Lines
259
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

ARM Broadcom STB platforms Device Tree Bindings
-----------------------------------------------
Boards with Broadcom Brahma15 ARM-based BCMxxxx (generally BCM7xxx variants)
SoC shall have the following DT organization:

Required root node properties:
    - compatible: "brcm,bcm<chip_id>", "brcm,brcmstb"

example:
/ {
    #address-cells = <2>;
    #size-cells = <2>;
    model = "Broadcom STB (bcm7445)";
    compatible = "brcm,bcm7445", "brcm,brcmstb";

Further, syscon nodes that map platform-specific registers used for general
system control is required:

    - compatible: "brcm,bcm<chip_id>-sun-top-ctrl", "syscon"
    - compatible: "brcm,bcm<chip_id>-cpu-biu-ctrl",
		  "brcm,brcmstb-cpu-biu-ctrl",
		  "syscon"
    - compatible: "brcm,bcm<chip_id>-hif-continuation", "syscon"

cpu-biu-ctrl node
-------------------
SoCs with Broadcom Brahma15 ARM-based and Brahma53 ARM64-based CPUs have a
specific Bus Interface Unit (BIU) block which controls and interfaces the CPU
complex to the different Memory Controller Ports (MCP), one per memory
controller (MEMC). This BIU block offers a feature called Write Pairing which
consists in collapsing two adjacent cache lines into a single (bursted) write
transaction towards the memory controller (MEMC) to maximize write bandwidth.

Required properties:

    - compatible: must be "brcm,bcm7445-cpu-biu-ctrl", "brcm,brcmstb-cpu-biu-ctrl", "syscon"

Optional properties:

    - brcm,write-pairing:
	Boolean property, which when present indicates that the chip
	supports write-pairing.

example:
    rdb {
        #address-cells = <1>;
        #size-cells = <1>;
        compatible = "simple-bus";
        ranges = <0 0x00 0xf0000000 0x1000000>;

        sun_top_ctrl: syscon@404000 {
            compatible = "brcm,bcm7445-sun-top-ctrl", "syscon";
            reg = <0x404000 0x51c>;
        };

        hif_cpubiuctrl: syscon@3e2400 {
            compatible = "brcm,bcm7445-cpu-biu-ctrl", "brcm,brcmstb-cpu-biu-ctrl", "syscon";
            reg = <0x3e2400 0x5b4>;
            brcm,write-pairing;
        };

        hif_continuation: syscon@452000 {
            compatible = "brcm,bcm7445-hif-continuation", "syscon";
            reg = <0x452000 0x100>;
        };
    };

Nodes that allow for support of SMP initialization and reboot are required:

smpboot

Annotation

Implementation Notes