usb: Add support for USB device discovery
This builds on the PCI support to enable the discovery of USB devices.
This is primarily intended to be used for the discovery of Edge-based
heterogeneous accelerators that are connected via USB, such as the Coral
USB Accelerator and the Intel NCS2 - our main motivation for adding this
capability to NFD, and as part of our work in the SODALITE H2020
project.
USB devices may define their base class at either the device or
interface levels. In the case where no device class is set, the
per-device interfaces are enumerated instead. USB devices may
furthermore have multiple interfaces, which may or may not use the
identical class across each interface. We therefore report device
existence for each unique class definition to enable more fine-grained
labelling and node selection.
The default labelling format includes the class, vendor and device
(product) IDs, as follows:
feature.node.kubernetes.io/usb-fe_1a6e_089a.present=true
As with PCI, a subset of device classes are whitelisted for matching.
By default, there are only a subset of device classes under which
accelerators tend to be mapped, which is used as the basis for
the whitelist. These are:
- Video
- Miscellaneous
- Application Specific
- Vendor Specific
For those interested in matching other classes, this may be extended
by using the UsbId rule provided through the custom source. A full
list of class codes is provided by the USB-IF at:
https://www.usb.org/defined-class-codes
For the moment, owing to a lack of a demonstrable use case, neither
the subclass nor the protocol information are exposed. If this
becomes necessary, support for these attributes can be trivially
added.
Signed-off-by: Paul Mundt <paul.mundt@adaptant.io>
2020-05-14 22:32:55 +02:00
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/*
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Copyright 2020 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package busutils
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import (
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"fmt"
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"io/ioutil"
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"log"
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"path"
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"path/filepath"
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"strings"
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)
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type UsbDeviceInfo map[string]string
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type UsbClassMap map[string]UsbDeviceInfo
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var DefaultUsbDevAttrs = []string{"class", "vendor", "device"}
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// The USB device sysfs files do not have terribly user friendly names, map
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// these for consistency with the PCI matcher.
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var devAttrFileMap = map[string]string{
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"class": "bDeviceClass",
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"device": "idProduct",
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"vendor": "idVendor",
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}
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func readSingleUsbSysfsAttribute(path string) (string, error) {
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data, err := ioutil.ReadFile(path)
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if err != nil {
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return "", fmt.Errorf("failed to read device attribute %s: %v", filepath.Base(path), err)
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}
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attrVal := strings.TrimSpace(string(data))
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return attrVal, nil
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}
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// Read a single USB device attribute
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// A USB attribute in this context, maps to the corresponding sysfs file
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func readSingleUsbAttribute(devPath string, attrName string) (string, error) {
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return readSingleUsbSysfsAttribute(path.Join(devPath, devAttrFileMap[attrName]))
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}
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// Read information of one USB device
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func readUsbDevInfo(devPath string, deviceAttrSpec map[string]bool) (UsbClassMap, error) {
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classmap := UsbClassMap{}
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info := UsbDeviceInfo{}
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2020-05-19 16:39:02 +03:00
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for attr := range deviceAttrSpec {
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usb: Add support for USB device discovery
This builds on the PCI support to enable the discovery of USB devices.
This is primarily intended to be used for the discovery of Edge-based
heterogeneous accelerators that are connected via USB, such as the Coral
USB Accelerator and the Intel NCS2 - our main motivation for adding this
capability to NFD, and as part of our work in the SODALITE H2020
project.
USB devices may define their base class at either the device or
interface levels. In the case where no device class is set, the
per-device interfaces are enumerated instead. USB devices may
furthermore have multiple interfaces, which may or may not use the
identical class across each interface. We therefore report device
existence for each unique class definition to enable more fine-grained
labelling and node selection.
The default labelling format includes the class, vendor and device
(product) IDs, as follows:
feature.node.kubernetes.io/usb-fe_1a6e_089a.present=true
As with PCI, a subset of device classes are whitelisted for matching.
By default, there are only a subset of device classes under which
accelerators tend to be mapped, which is used as the basis for
the whitelist. These are:
- Video
- Miscellaneous
- Application Specific
- Vendor Specific
For those interested in matching other classes, this may be extended
by using the UsbId rule provided through the custom source. A full
list of class codes is provided by the USB-IF at:
https://www.usb.org/defined-class-codes
For the moment, owing to a lack of a demonstrable use case, neither
the subclass nor the protocol information are exposed. If this
becomes necessary, support for these attributes can be trivially
added.
Signed-off-by: Paul Mundt <paul.mundt@adaptant.io>
2020-05-14 22:32:55 +02:00
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attrVal, _ := readSingleUsbAttribute(devPath, attr)
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if len(attrVal) > 0 {
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info[attr] = attrVal
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}
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}
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// USB devices encode their class information either at the device or the interface level. If the device class
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// is set, return as-is.
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if info["class"] != "00" {
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classmap[info["class"]] = info
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} else {
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// Otherwise, if a 00 is presented at the device level, descend to the interface level.
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interfaces, err := filepath.Glob(devPath + "/*/bInterfaceClass")
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if err != nil {
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return classmap, err
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}
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// A device may, notably, have multiple interfaces with mixed classes, so we create a unique device for each
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// unique interface class.
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for _, intf := range interfaces {
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// Determine the interface class
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attrVal, err := readSingleUsbSysfsAttribute(intf)
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if err != nil {
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return classmap, err
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}
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attr := UsbDeviceInfo{}
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for k, v := range info {
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attr[k] = v
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}
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attr["class"] = attrVal
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classmap[attrVal] = attr
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}
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}
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return classmap, nil
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}
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// List available USB devices and retrieve device attributes.
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// deviceAttrSpec is a map which specifies which attributes to retrieve.
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// a false value for a specific attribute marks the attribute as optional.
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// a true value for a specific attribute marks the attribute as mandatory.
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// "class" attribute is considered mandatory.
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// DetectUsb() will fail if the retrieval of a mandatory attribute fails.
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func DetectUsb(deviceAttrSpec map[string]bool) (map[string][]UsbDeviceInfo, error) {
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// Unlike PCI, the USB sysfs interface includes entries not just for
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// devices. We work around this by globbing anything that includes a
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// valid product ID.
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const devicePath = "/sys/bus/usb/devices/*/idProduct"
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devInfo := make(map[string][]UsbDeviceInfo)
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devices, err := filepath.Glob(devicePath)
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if err != nil {
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return nil, err
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}
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// "class" is a mandatory attribute, inject it to spec if needed.
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deviceAttrSpec["class"] = true
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// Iterate over devices
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for _, device := range devices {
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devMap, err := readUsbDevInfo(filepath.Dir(device), deviceAttrSpec)
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if err != nil {
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log.Print(err)
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continue
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}
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for class, info := range devMap {
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devInfo[class] = append(devInfo[class], info)
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}
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}
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return devInfo, nil
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}
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