// Copyright 2013 Google Inc. 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
/*
#ifndef OS_WINDOWS
#include "os/threads_posix.h"
#endif
#include "libusbi.h"
#include "libusb.h"
*/
import "C"
import (
"fmt"
"reflect"
"sync"
"time"
"unsafe"
)
var DefaultReadTimeout = 1 * time.Second
var DefaultWriteTimeout = 1 * time.Second
var DefaultControlTimeout = 250 * time.Millisecond //5 * time.Second
type Device struct {
handle *C.libusb_device_handle
// 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[uint8]int
// Detached kernel interfaces
detached map[uint8]int
}
func newDevice(handle *C.libusb_device_handle, desc *Descriptor) (*Device, error) {
ifaces := 0
d := &Device{
handle: handle,
Descriptor: desc,
ReadTimeout: DefaultReadTimeout,
WriteTimeout: DefaultWriteTimeout,
ControlTimeout: DefaultControlTimeout,
lock: new(sync.Mutex),
claimed: make(map[uint8]int, ifaces),
detached: make(map[uint8]int),
}
if err := d.detachKernelDriver(); err != nil {
d.Close()
return nil, err
}
return d, nil
}
// detachKernelDriver detaches any active kernel drivers, if supported by the platform.
// If there are any errors, like Context.ListDevices, only the final one will be returned.
func (d *Device) detachKernelDriver() (err error) {
for _, cfg := range d.Configs {
for _, iface := range cfg.Interfaces {
switch activeErr := C.libusb_kernel_driver_active(d.handle, C.int(iface.Number)); activeErr {
case C.LIBUSB_ERROR_NOT_SUPPORTED:
// no need to do any futher checking, no platform support
return
case 0:
continue
case 1:
switch detachErr := C.libusb_detach_kernel_driver(d.handle, C.int(iface.Number)); detachErr {
case C.LIBUSB_ERROR_NOT_SUPPORTED:
// shouldn't ever get here, should be caught by the outer switch
return
case 0:
d.detached[iface.Number]++
case C.LIBUSB_ERROR_NOT_FOUND:
// this status is returned if libusb's driver is already attached to the device
d.detached[iface.Number]++
default:
err = fmt.Errorf("usb: detach kernel driver: %s", usbError(detachErr))
}
default:
err = fmt.Errorf("usb: active kernel driver check: %s", usbError(activeErr))
}
}
}
return
}
// attachKernelDriver re-attaches kernel drivers to any previously detached interfaces, if supported by the platform.
// If there are any errors, like Context.ListDevices, only the final one will be returned.
func (d *Device) attachKernelDriver() (err error) {
for iface := range d.detached {
switch attachErr := C.libusb_attach_kernel_driver(d.handle, C.int(iface)); attachErr {
case C.LIBUSB_ERROR_NOT_SUPPORTED:
// no need to do any futher checking, no platform support
return
case 0:
continue
default:
err = fmt.Errorf("usb: attach kernel driver: %s", usbError(attachErr))
}
}
return
}
func (d *Device) Reset() error {
if errno := C.libusb_reset_device(d.handle); errno != 0 {
return usbError(errno)
}
return nil
}
func (d *Device) Control(rType, request uint8, val, idx uint16, data []byte) (int, error) {
//log.Printf("control xfer: %d:%d/%d:%d %x", idx, rType, request, val, string(data))
dataSlice := (*reflect.SliceHeader)(unsafe.Pointer(&data))
n := C.libusb_control_transfer(
d.handle,
C.uint8_t(rType),
C.uint8_t(request),
C.uint16_t(val),
C.uint16_t(idx),
(*C.uchar)(unsafe.Pointer(dataSlice.Data)),
C.uint16_t(len(data)),
C.uint(d.ControlTimeout/time.Millisecond))
if n < 0 {
return int(n), usbError(n)
}
return int(n), nil
}
// ActiveConfig returns the config id (not the index) of the active configuration.
// This corresponds to the ConfigInfo.Config field.
func (d *Device) ActiveConfig() (uint8, error) {
var cfg C.int
if errno := C.libusb_get_configuration(d.handle, &cfg); errno < 0 {
return 0, usbError(errno)
}
return uint8(cfg), nil
}
// 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 uint8) error {
if errno := C.libusb_set_configuration(d.handle, C.int(cfg)); errno < 0 {
return usbError(errno)
}
return nil
}
// Close 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 {
C.libusb_release_interface(d.handle, C.int(iface))
}
d.attachKernelDriver()
C.libusb_close(d.handle)
d.handle = nil
return nil
}
func (d *Device) OpenEndpoint(conf, iface, setup, epoint uint8) (Endpoint, error) {
end := &endpoint{
Device: d,
}
var setAlternate bool
for _, c := range d.Configs {
if c.Config != conf {
continue
}
debug.Printf("found conf: %#v\n", c)
for _, i := range c.Interfaces {
if i.Number != iface {
continue
}
debug.Printf("found iface: %#v\n", i)
for i, s := range i.Setups {
if s.Alternate != setup {
continue
}
setAlternate = i != 0
debug.Printf("found setup: %#v [default: %v]\n", s, !setAlternate)
for _, e := range s.Endpoints {
debug.Printf("ep %02x search: %#v\n", epoint, s)
if e.Address != epoint {
continue
}
end.InterfaceSetup = s
end.EndpointInfo = e
switch tt := TransferType(e.Attributes) & TRANSFER_TYPE_MASK; tt {
case TRANSFER_TYPE_BULK:
end.xfer = bulk_xfer
case TRANSFER_TYPE_INTERRUPT:
end.xfer = interrupt_xfer
case TRANSFER_TYPE_ISOCHRONOUS:
end.xfer = isochronous_xfer
default:
return nil, fmt.Errorf("usb: %s transfer is unsupported", tt)
}
goto found
}
return nil, fmt.Errorf("usb: unknown endpoint %02x", epoint)
}
return nil, fmt.Errorf("usb: unknown setup %02x", setup)
}
return nil, fmt.Errorf("usb: unknown interface %02x", iface)
}
return nil, fmt.Errorf("usb: unknown configuration %02x", conf)
found:
// Set the configuration
var activeConf C.int
if errno := C.libusb_get_configuration(d.handle, &activeConf); errno < 0 {
return nil, fmt.Errorf("usb: getcfg: %s", usbError(errno))
}
if int(activeConf) != int(conf) {
if errno := C.libusb_set_configuration(d.handle, C.int(conf)); errno < 0 {
return nil, fmt.Errorf("usb: setcfg: %s", usbError(errno))
}
}
// Claim the interface
if errno := C.libusb_claim_interface(d.handle, C.int(iface)); errno < 0 {
return nil, fmt.Errorf("usb: claim: %s", usbError(errno))
}
// Increment the claim count
d.lock.Lock()
d.claimed[iface]++
d.lock.Unlock() // unlock immediately because the next calls may block
// Choose the alternate
if setAlternate {
if errno := C.libusb_set_interface_alt_setting(d.handle, C.int(iface), C.int(setup)); errno < 0 {
debug.Printf("altsetting error: %s", usbError(errno))
return nil, fmt.Errorf("usb: setalt: %s", usbError(errno))
}
}
return end, nil
}
func (d *Device) GetStringDescriptor(desc_index int) (string, error) {
// allocate 200-byte array limited the length of string descriptor
goBuffer := make([]byte, 200)
// get string descriptor from libusb. if errno < 0 then there are any errors.
// if errno >= 0; it is a length of result string descriptor
errno := C.libusb_get_string_descriptor_ascii(
d.handle,
C.uint8_t(desc_index),
(*C.uchar)(unsafe.Pointer(&goBuffer[0])),
200)
// if any errors occur
if errno < 0 {
return "", fmt.Errorf("usb: getstr: %s", usbError(errno))
}
// convert slice of byte to string with limited length from errno
stringDescriptor := string(goBuffer[:errno])
return stringDescriptor, nil
}
