108 lines
2.1 KiB
Go
108 lines
2.1 KiB
Go
package usb
|
|
|
|
/*
|
|
#include <libusb-1.0/libusb.h>
|
|
|
|
libusb_transfer_cb_fn callback();
|
|
*/
|
|
import "C"
|
|
|
|
import (
|
|
"log"
|
|
"reflect"
|
|
"runtime"
|
|
"time"
|
|
"unsafe"
|
|
)
|
|
|
|
//export iso_callback
|
|
func iso_callback(cptr unsafe.Pointer) {
|
|
ch := *(*chan struct{})(cptr)
|
|
close(ch)
|
|
}
|
|
|
|
func (end *endpoint) allocTransfer() *Transfer {
|
|
// Use libusb_get_max_iso_packet_size ?
|
|
const (
|
|
iso_packets = 242
|
|
packet_size = 1760
|
|
)
|
|
|
|
xfer := C.libusb_alloc_transfer(C.int(iso_packets))
|
|
if xfer == nil {
|
|
log.Printf("usb: transfer allocation failed?!")
|
|
return nil
|
|
}
|
|
|
|
xfer.dev_handle = end.Device.handle
|
|
xfer.endpoint = C.uchar(end.Address)
|
|
xfer._type = C.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
|
|
|
|
xfer.callback = C.callback()
|
|
xfer.timeout = C.uint(5 * time.Second / time.Millisecond)
|
|
|
|
buf := make([]byte, iso_packets*packet_size)
|
|
xfer.num_iso_packets = iso_packets
|
|
xfer.buffer = (*C.uchar)((unsafe.Pointer)(&buf[0]))
|
|
xfer.length = C.int(len(buf))
|
|
C.libusb_set_iso_packet_lengths(xfer, C.uint(len(buf)))
|
|
pkts := *(*[]C.struct_libusb_packet_descriptor)(unsafe.Pointer(&reflect.SliceHeader{
|
|
Data: uintptr(unsafe.Pointer(&xfer.iso_packet_desc)),
|
|
Len: iso_packets,
|
|
Cap: iso_packets,
|
|
}))
|
|
|
|
done := make(chan struct{})
|
|
xfer.user_data = (unsafe.Pointer)(&done)
|
|
|
|
t := &Transfer{
|
|
xfer: xfer,
|
|
pkts: pkts,
|
|
done: done,
|
|
buf: buf,
|
|
}
|
|
|
|
runtime.SetFinalizer(t, (*Transfer).Close)
|
|
|
|
return t
|
|
}
|
|
|
|
type Transfer struct {
|
|
xfer *C.struct_libusb_transfer
|
|
pkts []C.struct_libusb_packet_descriptor
|
|
done chan struct{}
|
|
buf []byte
|
|
}
|
|
|
|
func (xfer *Transfer) Submit() error {
|
|
if errno := C.libusb_submit_transfer(xfer.xfer); errno < 0 {
|
|
return usbError(errno)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (xfer *Transfer) Wait() (n int, err error) {
|
|
<-xfer.done
|
|
n = int(xfer.xfer.actual_length)
|
|
for _, pkt := range xfer.pkts {
|
|
log.Printf("PACKET[%4d] - %#v", pkt)
|
|
}
|
|
return n, err
|
|
}
|
|
|
|
func (xfer *Transfer) Close() error {
|
|
C.libusb_free_transfer(xfer.xfer)
|
|
return nil
|
|
}
|
|
|
|
func isochronous_xfer(e *endpoint, buf []byte, timeout time.Duration) (int, error) {
|
|
xfer := e.allocTransfer()
|
|
defer xfer.Close()
|
|
|
|
if err := xfer.Submit(); err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return xfer.Wait()
|
|
}
|