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freebsd/sys/dev/usb/usb_fdt_support.h
Ian Lepore bac5ec96f4 Add common support functions for USB devices configured via FDT data.
FDT data is sometimes used to configure usb devices which are hardwired into
an embedded system. Because the devices are instantiated by the usb
enumeration process rather than by ofwbus iterating through the fdt data, it
is somewhat difficult for a usb driver to locate fdt data that belongs to
it. In the past, various ad-hoc methods have been used, which can lead to
errors such applying configuration that should apply only to a hardwired
device onto a similar device attached by the user at runtime. For example,
if the user adds an ethernet device that uses the same driver as the builtin
ethernet, both devices might end up with the same MAC address.

These changes add a new usb_fdt_get_node() helper function that a driver can
use to locate FDT data that belongs to a single unique instance of the
device. This function locates the proper FDT data using the mechanism
detailed in the standard "usb-device.txt" binding document [1].

There is also a new usb_fdt_get_mac_addr() function, used to retrieve the
mac address for a given device instance from the fdt data. It uses
usb_fdt_get_node() to locate the right node in the FDT data, and attempts to
obtain the mac-address or local-mac-address property (in that order, the
same as linux does it).

The existing if_smsc driver is modified to use the new functions, both as an
example and for testing the new functions. Rpi and rpi2 boards use this
driver and provide the mac address via the fdt data.

[1] https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/usb/usb-device.txt

Differential Revision:	https://reviews.freebsd.org/D20262
2019-05-19 16:56:59 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _USB_FDT_SUPPORT_H_
#define _USB_FDT_SUPPORT_H_
struct usb_device;
struct usb_ether;
/*
* Get the device's MAC address from the FDT data. Fills in ue->ue_eaddr and
* returns 0 on success, otherwise leaves ue_eaddr untouched and returns
* non-zero. This first attempts to get the address from the "mac-address"
* property, and if that's not valid it tries the "local-mac-address" property;
* this matches the linux interpretation of the precedence of those properties.
*/
int usb_fdt_get_mac_addr(device_t dev, struct usb_ether* ue);
/* Get the FDT node for dev. Returns -1 if dev is not in the FDT data. */
phandle_t usb_fdt_get_node(device_t dev, struct usb_device* udev);
#endif