Files
gousb/usb/device.go
2017-04-26 22:22:07 +02:00

234 lines
6.4 KiB
Go

// Copyright 2013 Google Inc. All rights reserved.
// Copyright 2016 the gousb Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package usb
import (
"fmt"
"sync"
"time"
)
var (
// DefaultReadTimeout controls the default timeout for IN endpoint transfers.
DefaultReadTimeout = 1 * time.Second
// DefaultWriteTimeout controls the default timeout for OUT endpoint transfers.
DefaultWriteTimeout = 1 * time.Second
// DefaultControlTimeout controls the default timeout for control transfers.
DefaultControlTimeout = 250 * time.Millisecond
)
// Device represents an opened USB device.
type Device struct {
handle *libusbDevHandle
// Embed the device information for easy access
*Descriptor
// Timeouts
ReadTimeout time.Duration
WriteTimeout time.Duration
ControlTimeout time.Duration
// Claimed interfaces
lock *sync.Mutex
claimed map[int]int
}
func newDevice(handle *libusbDevHandle, desc *Descriptor) *Device {
ifaces := 0
d := &Device{
handle: handle,
Descriptor: desc,
ReadTimeout: DefaultReadTimeout,
WriteTimeout: DefaultWriteTimeout,
ControlTimeout: DefaultControlTimeout,
lock: new(sync.Mutex),
claimed: make(map[int]int, ifaces),
}
return d
}
// Reset performs a USB port reset to reinitialize a device.
func (d *Device) Reset() error {
return libusb.reset(d.handle)
}
// Control sends a control request to the device.
func (d *Device) Control(rType, request uint8, val, idx uint16, data []byte) (int, error) {
return libusb.control(d.handle, d.ControlTimeout, rType, request, val, idx, data)
}
// ActiveConfig returns the config id (not the index) of the active configuration.
// This corresponds to the ConfigInfo.Config field.
func (d *Device) ActiveConfig() (int, error) {
ret, err := libusb.getConfig(d.handle)
return int(ret), err
}
// SetConfig attempts to change the active configuration.
// The cfg provided is the config id (not the index) of the configuration to set,
// which corresponds to the ConfigInfo.Config field.
func (d *Device) SetConfig(cfg int) error {
return libusb.setConfig(d.handle, uint8(cfg))
}
// Close closes the device.
func (d *Device) Close() error {
if d.handle == nil {
return fmt.Errorf("usb: double close on device")
}
d.lock.Lock()
defer d.lock.Unlock()
for iface := range d.claimed {
libusb.release(d.handle, uint8(iface))
}
libusb.close(d.handle)
d.handle = nil
return nil
}
func (d *Device) openEndpoint(cfgNum, ifNum, setNum, epAddr int) (*endpoint, error) {
var cfg *ConfigInfo
for _, c := range d.Configs {
if c.Config == cfgNum {
debug.Printf("found conf: %+v\n", c)
cfg = &c
break
}
}
if cfg == nil {
return nil, fmt.Errorf("usb: unknown configuration 0x%02x", cfgNum)
}
var intf *InterfaceInfo
for _, i := range cfg.Interfaces {
if i.Number == ifNum {
debug.Printf("found iface: %+v\n", i)
intf = &i
break
}
}
if intf == nil {
return nil, fmt.Errorf("usb: unknown interface 0x%02x", ifNum)
}
var setAlternate bool
var ifs *InterfaceSetting
for i, s := range intf.AltSettings {
if s.Alternate == setNum {
setAlternate = i != 0
debug.Printf("found setup: %+v [default: %v]\n", s, !setAlternate)
ifs = &s
break
}
}
if ifs == nil {
return nil, fmt.Errorf("usb: unknown setup 0x%02x", setNum)
}
var ep *EndpointInfo
for _, e := range ifs.Endpoints {
if endpointAddr(e.Number, e.Direction) == epAddr {
debug.Printf("found ep #%d %s in %+v\n", e.Number, e.Direction, *ifs)
ep = &e
break
}
}
if ep == nil {
return nil, fmt.Errorf("usb: didn't find endpoint address 0x%02x", epAddr)
}
end := newEndpoint(d.handle, *ifs, *ep)
// Set the configuration
activeConf, err := libusb.getConfig(d.handle)
if err != nil {
return nil, fmt.Errorf("usb: getcfg: %s", err)
}
if activeConf != uint8(cfgNum) {
if err := libusb.setConfig(d.handle, uint8(cfgNum)); err != nil {
return nil, fmt.Errorf("usb: setcfg: %s", err)
}
}
// Claim the interface
if err := libusb.claim(d.handle, uint8(ifNum)); err != nil {
return nil, fmt.Errorf("usb: claim: %s", err)
}
// Increment the claim count
d.lock.Lock()
d.claimed[ifNum]++
d.lock.Unlock() // unlock immediately because the next calls may block
// Choose the alternate
if setAlternate {
if err := libusb.setAlt(d.handle, uint8(ifNum), uint8(setNum)); err != nil {
return nil, fmt.Errorf("usb: setalt: %s", err)
}
}
return end, nil
}
// InEndpoint prepares an IN endpoint for transfer.
func (d *Device) InEndpoint(cfgNum, ifNum, setNum, epNum int) (*InEndpoint, error) {
ep, err := d.openEndpoint(cfgNum, ifNum, setNum, endpointAddr(epNum, EndpointDirectionIn))
if err != nil {
return nil, err
}
ep.SetTimeout(d.ReadTimeout)
return &InEndpoint{
endpoint: ep,
}, nil
}
// OutEndpoint prepares an OUT endpoint for transfer.
func (d *Device) OutEndpoint(cfgNum, ifNum, setNum, epNum int) (*OutEndpoint, error) {
ep, err := d.openEndpoint(cfgNum, ifNum, setNum, endpointAddr(epNum, EndpointDirectionOut))
if err != nil {
return nil, err
}
ep.SetTimeout(d.WriteTimeout)
return &OutEndpoint{
endpoint: ep,
}, nil
}
// GetStringDescriptor returns a device string descriptor with the given index
// number. The first supported language is always used and the returned
// descriptor string is converted to ASCII (non-ASCII characters are replaced
// with "?").
func (d *Device) GetStringDescriptor(descIndex int) (string, error) {
return libusb.getStringDesc(d.handle, descIndex)
}
// SetAutoDetach enables/disables libusb's automatic kernel driver detachment.
// When autodetach is enabled libusb will automatically detach the kernel driver
// on the interface and reattach it when releasing the interface.
// Automatic kernel driver detachment is disabled on newly opened device handles by default.
func (d *Device) SetAutoDetach(autodetach bool) error {
var autodetachInt int
switch autodetach {
case true:
autodetachInt = 1
case false:
autodetachInt = 0
}
return libusb.setAutoDetach(d.handle, autodetachInt)
}