core.py

# MicroPython USB host library, compatible with PyUSB.
# MIT license; Copyright (c) 2021-2024 Damien P. George

importsys
importffi
importuctypes

ifsys.maxsize>>32:
UINTPTR_SIZE=8
UINTPTR=uctypes.UINT64
else:
UINTPTR_SIZE=4
UINTPTR=uctypes.UINT32


def_align_word(x):
return (x+UINTPTR_SIZE-1) &~(UINTPTR_SIZE-1)


ptr_descriptor= (0|uctypes.ARRAY, 1|UINTPTR)

libusb_device_descriptor= {
"bLength": 0|uctypes.UINT8,
"bDescriptorType": 1|uctypes.UINT8,
"bcdUSB": 2|uctypes.UINT16,
"bDeviceClass": 4|uctypes.UINT8,
"bDeviceSubClass": 5|uctypes.UINT8,
"bDeviceProtocol": 6|uctypes.UINT8,
"bMaxPacketSize0": 7|uctypes.UINT8,
"idVendor": 8|uctypes.UINT16,
"idProduct": 10|uctypes.UINT16,
"bcdDevice": 12|uctypes.UINT16,
"iManufacturer": 14|uctypes.UINT8,
"iProduct": 15|uctypes.UINT8,
"iSerialNumber": 16|uctypes.UINT8,
"bNumConfigurations": 17|uctypes.UINT8,
}

libusb_config_descriptor= {
"bLength": 0|uctypes.UINT8,
"bDescriptorType": 1|uctypes.UINT8,
"wTotalLength": 2|uctypes.UINT16,
"bNumInterfaces": 4|uctypes.UINT8,
"bConfigurationValue": 5|uctypes.UINT8,
"iConfiguration": 6|uctypes.UINT8,
"bmAttributes": 7|uctypes.UINT8,
"MaxPower": 8|uctypes.UINT8,
"interface": _align_word(9) |UINTPTR, # array of libusb_interface
"extra": (_align_word(9) +UINTPTR_SIZE) |UINTPTR,
"extra_length": (_align_word(9) +2*UINTPTR_SIZE) |uctypes.INT,
}

libusb_interface= {
"altsetting": 0|UINTPTR, # array of libusb_interface_descriptor
"num_altsetting": UINTPTR_SIZE|uctypes.INT,
}

libusb_interface_descriptor= {
"bLength": 0|uctypes.UINT8,
"bDescriptorType": 1|uctypes.UINT8,
"bInterfaceNumber": 2|uctypes.UINT8,
"bAlternateSetting": 3|uctypes.UINT8,
"bNumEndpoints": 4|uctypes.UINT8,
"bInterfaceClass": 5|uctypes.UINT8,
"bInterfaceSubClass": 6|uctypes.UINT8,
"bInterfaceProtocol": 7|uctypes.UINT8,
"iInterface": 8|uctypes.UINT8,
"endpoint": _align_word(9) |UINTPTR,
"extra": (_align_word(9) +UINTPTR_SIZE) |UINTPTR,
"extra_length": (_align_word(9) +2*UINTPTR_SIZE) |uctypes.INT,
}

libusb=ffi.open("libusb-1.0.so")
libusb_init=libusb.func("i", "libusb_init", "p")
libusb_exit=libusb.func("v", "libusb_exit", "p")
libusb_get_device_list=libusb.func("i", "libusb_get_device_list", "pp") # return is ssize_t
libusb_free_device_list=libusb.func("v", "libusb_free_device_list", "pi")
libusb_get_device_descriptor=libusb.func("i", "libusb_get_device_descriptor", "pp")
libusb_get_config_descriptor=libusb.func("i", "libusb_get_config_descriptor", "pBp")
libusb_free_config_descriptor=libusb.func("v", "libusb_free_config_descriptor", "p")
libusb_open=libusb.func("i", "libusb_open", "pp")
libusb_set_configuration=libusb.func("i", "libusb_set_configuration", "pi")
libusb_claim_interface=libusb.func("i", "libusb_claim_interface", "pi")
libusb_control_transfer=libusb.func("i", "libusb_control_transfer", "pBBHHpHI")


def_new(sdesc):
buf=bytearray(uctypes.sizeof(sdesc))
s=uctypes.struct(uctypes.addressof(buf), sdesc)
returns


classInterface:
def__init__(self, descr):
# Public attributes.
self.bInterfaceClass=descr.bInterfaceClass
self.bInterfaceSubClass=descr.bInterfaceSubClass
self.iInterface=descr.iInterface
self.extra_descriptors=uctypes.bytes_at(descr.extra, descr.extra_length)


classConfiguration:
def__init__(self, dev, cfg_idx):
cfgs=_new(ptr_descriptor)
iflibusb_get_config_descriptor(dev._dev, cfg_idx, cfgs) !=0:
libusb_exit(0)
raiseException
descr=uctypes.struct(cfgs[0], libusb_config_descriptor)

# Extract all needed info because descr is going to be free'd at the end.
self._itfs= []
itf_array=uctypes.struct(
descr.interface, (0|uctypes.ARRAY, descr.bNumInterfaces, libusb_interface)
 )
foriinrange(descr.bNumInterfaces):
itf=itf_array[i]
alt_array=uctypes.struct(
itf.altsetting,
 (0|uctypes.ARRAY, itf.num_altsetting, libusb_interface_descriptor),
 )
forjinrange(itf.num_altsetting):
alt=alt_array[j]
self._itfs.append(Interface(alt))

# Public attributes.
self.bNumInterfaces=descr.bNumInterfaces
self.bConfigurationValue=descr.bConfigurationValue
self.bmAttributes=descr.bmAttributes
self.bMaxPower=descr.MaxPower
self.extra_descriptors=uctypes.bytes_at(descr.extra, descr.extra_length)

# Free descr memory in the driver.
libusb_free_config_descriptor(cfgs[0])

def__iter__(self):
returniter(self._itfs)


classDevice:
_TIMEOUT_DEFAULT=1000

def__init__(self, dev, descr):
self._dev=dev
self._num_cfg=descr.bNumConfigurations
self._handle=None
self._claim_itf=set()

# Public attributes.
self.idVendor=descr.idVendor
self.idProduct=descr.idProduct

def__iter__(self):
foriinrange(self._num_cfg):
yieldConfiguration(self, i)

def__getitem__(self, i):
returnConfiguration(self, i)

def_open(self):
ifself._handleisNone:
# Open the USB device.
handle=_new(ptr_descriptor)
iflibusb_open(self._dev, handle) !=0:
libusb_exit(0)
raiseException
self._handle=handle[0]

def_claim_interface(self, i):
iflibusb_claim_interface(self._handle, i) !=0:
libusb_exit(0)
raiseException

defset_configuration(self):
# Select default configuration.
self._open()
cfg=Configuration(self, 0).bConfigurationValue
ret=libusb_set_configuration(self._handle, cfg)
ifret!=0:
libusb_exit(0)
raiseException

defctrl_transfer(
self, bmRequestType, bRequest, wValue=0, wIndex=0, data_or_wLength=None, timeout=None
 ):
ifdata_or_wLengthisNone:
l=0
data=bytes()
elifisinstance(data_or_wLength, int):
l=data_or_wLength
data=bytearray(l)
else:
l=len(data_or_wLength)
data=data_or_wLength
self._open()
ifwIndex&0xFFnotinself._claim_itf:
self._claim_interface(wIndex&0xFF)
self._claim_itf.add(wIndex&0xFF)
iftimeoutisNone:
timeout=self._TIMEOUT_DEFAULT
ret=libusb_control_transfer(
self._handle, bmRequestType, bRequest, wValue, wIndex, data, l, timeout*1000
 )
ifret<0:
libusb_exit(0)
raiseException
ifisinstance(data_or_wLength, int):
returndata
else:
returnret


deffind(*, find_all=False, custom_match=None, idVendor=None, idProduct=None):
iflibusb_init(0) <0:
raiseException

devs=_new(ptr_descriptor)
count=libusb_get_device_list(0, devs)
ifcount<0:
libusb_exit(0)
raiseException

dev_array=uctypes.struct(devs[0], (0|uctypes.ARRAY, count|UINTPTR))
descr=_new(libusb_device_descriptor)
devices=None
foriinrange(count):
libusb_get_device_descriptor(dev_array[i], descr)
ifidVendoranddescr.idVendor!=idVendor:
continue
ifidProductanddescr.idProduct!=idProduct:
continue
device=Device(dev_array[i], descr)
ifcustom_matchandnotcustom_match(device):
continue
ifnotfind_all:
returndevice
ifnotdevices:
devices= []
devices.append(device)
returndevices