OF_xref_from_device9freebsd

Usage

Overview

When a device tree node references another node, the driver may need to get a device_t instance associated with the referenced node. For instance, an Ethernet driver accessing a PHY device. To make this possible, the kernel maintains a table that maps effective handles to device_t instances.

OF_device_register_xref() adds a map entry from the effective phandle xref to device dev. If a mapping entry for xref already exists, it is replaced with the new one. The function always returns 0.

OF_device_from_xref() returns a device_t instance associated with the effective phandle xref. If no such mapping exists, the function returns NULL.

OF_xref_from_device() returns the effective phandle associated with the device dev. If no such mapping exists, the function returns 0.

Examples

    static int
    acmephy_attach(device_t dev)
    {
        phandle_t node;
	/* PHY node is referenced from eth device, register it */
        node = ofw_bus_get_node(dev);
        OF_device_register_xref(OF_xref_from_node(node), dev);
        return (0);
    }