1# Copyright 2015 The Chromium OS Authors. All rights reserved. 2# Use of this source code is governed by a BSD-style license that can be 3# found in the LICENSE file. 4 5"""An interface to access the local USB facade.""" 6 7import glob 8import logging 9import os 10import time 11 12from autotest_lib.client.bin import utils 13from autotest_lib.client.cros.audio import cras_dbus_utils 14from autotest_lib.client.cros.audio import cras_utils 15 16 17class USBFacadeNativeError(Exception): 18 """Error in USBFacadeNative.""" 19 pass 20 21 22class USBFacadeNative(object): 23 """Facade to access the USB-related functionality. 24 25 Property: 26 _drivers_manager: A USBDeviceDriversManager object used to manage the 27 status of drivers associated with the USB audio gadget 28 on the host side. 29 30 """ 31 _DEFAULT_DEVICE_PRODUCT_NAME = 'Linux USB Audio Gadget' 32 _TIMEOUT_FINDING_USB_DEVICE_SECS = 10 33 _TIMEOUT_CRAS_NODES_CHANGE_SECS = 30 34 35 def __init__(self): 36 """Initializes the USB facade. 37 38 The _drivers_manager is set with a USBDeviceDriversManager, which is 39 used to control the visibility and availability of a USB device on a 40 host Cros device. 41 42 """ 43 self._drivers_manager = USBDeviceDriversManager() 44 45 46 def _reenumerate_usb_devices(self): 47 """Resets host controller to re-enumerate usb devices.""" 48 self._drivers_manager.reset_host_controller() 49 50 51 def plug(self): 52 """Sets and plugs the USB device into the host. 53 54 The USB device is initially set to one with the default product name, 55 which is assumed to be the name of the USB audio gadget on Chameleon. 56 This method blocks until Cras enumerate USB nodes within a timeout 57 specified in _wait_for_nodes_changed. 58 59 """ 60 # Only supports controlling one USB device of default name. 61 device_name = self._DEFAULT_DEVICE_PRODUCT_NAME 62 63 def find_usb_device(): 64 """Find USB device with name device_name. 65 66 @returns: True if succeed to find the device, False otherwise. 67 68 """ 69 try: 70 self._drivers_manager.find_usb_device(device_name) 71 return True 72 except USBDeviceDriversManagerError: 73 logging.debug('Can not find %s yet' % device_name) 74 return False 75 76 if self._drivers_manager.has_found_device(device_name): 77 if self._drivers_manager.drivers_are_bound(): 78 return 79 self._drivers_manager.bind_usb_drivers() 80 self._wait_for_nodes_changed() 81 else: 82 # If driver manager has not found device yet, re-enumerate USB 83 # devices. The correct USB driver will be binded automatically. 84 self._reenumerate_usb_devices() 85 self._wait_for_nodes_changed() 86 # Wait some time for paths and fields in sysfs to be created. 87 utils.poll_for_condition( 88 condition=find_usb_device, 89 desc='Find USB device', 90 timeout=self._TIMEOUT_FINDING_USB_DEVICE_SECS) 91 92 93 def unplug(self): 94 """Unplugs the USB device from the host.""" 95 self._drivers_manager.unbind_usb_drivers() 96 97 98 def _wait_for_nodes_changed(self): 99 """Waits for Cras to enumerate USB nodes. 100 101 USB nodes will be plugged, but not necessarily selected. 102 103 """ 104 def find_usb_node(): 105 """Checks if USB input and output nodes are plugged. 106 107 @returns: True if USB input and output nodes are plugged. False 108 otherwise. 109 """ 110 out_nodes, in_nodes = cras_utils.get_plugged_node_types() 111 logging.info('Cras nodes: output: %s, input: %s', 112 out_nodes, in_nodes) 113 return 'USB' in out_nodes and 'USB' in in_nodes 114 115 utils.poll_for_condition( 116 condition=find_usb_node, 117 desc='Find USB node', 118 timeout=self._TIMEOUT_CRAS_NODES_CHANGE_SECS) 119 120 121class USBDeviceDriversManagerError(Exception): 122 """Error in USBDeviceDriversManager.""" 123 pass 124 125 126class HostControllerDriver(object): 127 """Abstract a host controller driver. 128 129 This class stores id and path like: 130 path: /sys/bus/pci/drivers/echi_hcd 131 id: 0000:00:1a.0 132 Then, it can bind/unbind driver by writing 133 0000:00:1a.0 to /sys/bus/pci/drivers/echi_hcd/bind 134 and /sys/bus/pci/drivers/echi_hcd/unbind. 135 136 """ 137 def __init__(self, hcd_id, hcd_path): 138 """Inits an HostControllerDriver object. 139 140 @param hcd_id: The HCD id, e.g. 0000:00:1a.0 141 @param hcd_path: The path to HCD, e.g. /sys/bus/pci/drivers/echi_hcd. 142 143 """ 144 logging.debug('hcd id: %s, hcd path: %s', hcd_id, hcd_path) 145 self._hcd_id = hcd_id 146 self._hcd_path = hcd_path 147 148 149 def reset(self): 150 """Resets HCD by unbinding and binding driver.""" 151 utils.open_write_close( 152 os.path.join(self._hcd_path, 'unbind'), self._hcd_id) 153 utils.open_write_close( 154 os.path.join(self._hcd_path, 'bind'), self._hcd_id) 155 156 157class USBDeviceDriversManager(object): 158 """The class to control the USB drivers associated with a USB device. 159 160 By binding/unbinding certain USB driver, we can emulate the plug/unplug 161 action on that bus. However, this method only applies when the USB driver 162 has already been binded once. 163 To solve above problem, we can unbind then bind USB host controller driver 164 (HCD), then, HCD will re-enumerate all the USB devices. This method has 165 a side effect that all the USB devices will be disconnected for several 166 seconds, so we should only do it if needed. 167 Note that there might be multiple HCDs, e.g. 0000:00:1a.0 for bus1 and 168 0000:00:1b.0 for bus2. 169 170 Properties: 171 _device_product_name: The product name given to the USB device. 172 _device_bus_id: The bus ID of the USB device in the host. 173 _hcd_ids: The host controller driver IDs. 174 _hcds: A list of HostControllerDrivers. 175 176 """ 177 # The file to write to bind USB drivers of specified device 178 _USB_BIND_FILE_PATH = '/sys/bus/usb/drivers/usb/bind' 179 # The file to write to unbind USB drivers of specified device 180 _USB_UNBIND_FILE_PATH = '/sys/bus/usb/drivers/usb/unbind' 181 # The file path that exists when drivers are bound for current device 182 _USB_BOUND_DRIVERS_FILE_PATH = '/sys/bus/usb/drivers/usb/%s/driver' 183 # The pattern to glob usb drivers 184 _USB_DRIVER_GLOB_PATTERN = '/sys/bus/usb/drivers/usb/usb?/' 185 # The path to search for HCD on PCI or platform bus. 186 # The HCD id should be filled in the end. 187 _HCD_GLOB_PATTERNS = [ 188 '/sys/bus/pci/drivers/*/%s', 189 '/sys/bus/platform/drivers/*/%s'] 190 191 192 def __init__(self): 193 """Initializes the manager. 194 195 _device_product_name and _device_bus_id are initially set to None. 196 197 """ 198 self._device_product_name = None 199 self._device_bus_id = None 200 self._hcd_ids = None 201 self._hcds = None 202 self._find_hcd_ids() 203 self._create_hcds() 204 205 206 def _find_hcd_ids(self): 207 """Finds host controller driver ids for USB. 208 209 We can find the HCD id for USB from driver's realpath. 210 E.g. On ARM device: 211 /sys/bus/usb/drivers/usb/usb1 links to 212 /sys/devices/soc0/70090000.usb/xhci-hcd.0.auto/usb1 213 => HCD id is xhci-hcd.0.auto 214 215 E.g. On X86 device: 216 /sys/bus/usb/drivers/usb/usb1 links to 217 /sys/devices/pci0000:00/0000:00:14.0/usb1 218 => HCD id is 0000:00:14.0 219 220 There might be multiple HCD ids like 0000:00:1a.0 for usb1, 221 and 0000:00:1d.0 for usb2. 222 223 @raises: USBDeviceDriversManagerError if HCD id can not be found. 224 225 """ 226 def _get_dir_name(path): 227 return os.path.basename(os.path.dirname(path)) 228 229 hcd_ids = set() 230 231 for search_root_path in glob.glob(self._USB_DRIVER_GLOB_PATTERN): 232 hcd_id = _get_dir_name(os.path.realpath(search_root_path)) 233 hcd_ids.add(hcd_id) 234 235 if not hcd_ids: 236 raise USBDeviceDriversManagerError('Can not find HCD id') 237 238 self._hcd_ids = hcd_ids 239 logging.debug('Found HCD ids: %s', self._hcd_ids) 240 241 242 def _create_hcds(self): 243 """Finds HCD paths from HCD id and create HostControllerDrivers. 244 245 HCD is under /sys/bus/pci/drivers/ for x86 boards, and under 246 /sys/bus/platform/drivers/ for ARM boards. 247 248 For each HCD id, finds HCD by checking HCD id under it, e.g. 249 /sys/bus/pci/drivers/ehci_hcd has 0000:00:1a.0 under it. 250 Then, create a HostControllerDriver and store it in self._hcds. 251 252 @raises: USBDeviceDriversManagerError if there are multiple 253 HCD path found for a given HCD id. 254 255 @raises: USBDeviceDriversManagerError if no HostControllerDriver is found. 256 257 """ 258 self._hcds = [] 259 260 for hcd_id in self._hcd_ids: 261 for glob_pattern in self._HCD_GLOB_PATTERNS: 262 glob_pattern = glob_pattern % hcd_id 263 hcd_id_paths = glob.glob(glob_pattern) 264 if not hcd_id_paths: 265 continue 266 if len(hcd_id_paths) > 1: 267 raise USBDeviceDriversManagerError( 268 'More than 1 HCD id path found: %s' % hcd_id_paths) 269 hcd_id_path = hcd_id_paths[0] 270 271 # Gets /sys/bus/pci/drivers/echi_hcd from 272 # /sys/bus/pci/drivers/echi_hcd/0000:00:1a.0 273 hcd_path = os.path.dirname(hcd_id_path) 274 self._hcds.append( 275 HostControllerDriver(hcd_id=hcd_id, hcd_path=hcd_path)) 276 277 278 def reset_host_controller(self): 279 """Resets host controller by unbinding then binding HCD. 280 281 @raises: USBDeviceDriversManagerError if there is no HCD to control. 282 283 """ 284 if not self._hcds: 285 raise USBDeviceDriversManagerError('HCD is not found yet') 286 for hcd in self._hcds: 287 hcd.reset() 288 289 290 def _find_usb_device_bus_id(self, product_name): 291 """Finds the bus ID of the USB device with the given product name. 292 293 @param product_name: The product name of the USB device as it appears 294 to the host. 295 296 @returns: The bus ID of the USB device if it is detected by the host 297 successfully; or None if there is no such device with the 298 given product name. 299 300 """ 301 def product_matched(path): 302 """Checks if the product field matches expected product name. 303 304 @returns: True if the product name matches, False otherwise. 305 306 """ 307 read_product_name = utils.read_one_line(path) 308 logging.debug('Read product at %s = %s', path, read_product_name) 309 return read_product_name == product_name 310 311 # Find product field at these possible paths: 312 # '/sys/bus/usb/drivers/usb/usbX/X-Y/product' => bus id is X-Y. 313 # '/sys/bus/usb/drivers/usb/usbX/X-Y/X-Y.Z/product' => bus id is X-Y.Z. 314 315 for search_root_path in glob.glob(self._USB_DRIVER_GLOB_PATTERN): 316 logging.debug('search_root_path: %s', search_root_path) 317 for root, dirs, _ in os.walk(search_root_path): 318 logging.debug('root: %s', root) 319 for bus_id in dirs: 320 logging.debug('bus_id: %s', bus_id) 321 product_path = os.path.join(root, bus_id, 'product') 322 logging.debug('product_path: %s', product_path) 323 if not os.path.exists(product_path): 324 continue 325 if not product_matched(product_path): 326 continue 327 logging.debug( 328 'Bus ID of %s found: %s', product_name, bus_id) 329 return bus_id 330 331 logging.error('Bus ID of %s not found', product_name) 332 return None 333 334 335 def has_found_device(self, product_name): 336 """Checks if the device has been found. 337 338 @param product_name: The product name of the USB device as it appears 339 to the host. 340 341 @returns: True if device has been found, False otherwise. 342 343 """ 344 return self._device_product_name == product_name 345 346 347 def find_usb_device(self, product_name): 348 """Sets _device_product_name and _device_bus_id if it can be found. 349 350 @param product_name: The product name of the USB device as it appears 351 to the host. 352 353 @raises: USBDeviceDriversManagerError if device bus ID cannot be found 354 for the device with the given product name. 355 356 """ 357 device_bus_id = self._find_usb_device_bus_id(product_name) 358 if device_bus_id is None: 359 error_message = 'Cannot find device with product name: %s' 360 raise USBDeviceDriversManagerError(error_message % product_name) 361 else: 362 self._device_product_name = product_name 363 self._device_bus_id = device_bus_id 364 365 366 def drivers_are_bound(self): 367 """Checks whether the drivers with the of current device are bound. 368 369 If the drivers are already bound, calling bind_usb_drivers will be 370 redundant and also result in an error. 371 372 @return: True if the path to the drivers exist, meaning the drivers 373 are already bound. False otherwise. 374 375 """ 376 if self._device_bus_id is None: 377 raise USBDeviceDriversManagerError('USB Bus ID is not set yet.') 378 driver_path = self._USB_BOUND_DRIVERS_FILE_PATH % self._device_bus_id 379 return os.path.exists(driver_path) 380 381 382 def bind_usb_drivers(self): 383 """Binds the USB driver(s) of the current device to the host. 384 385 This is applied to all the drivers associated with and listed under 386 the USB device with the current _device_product_name and _device_bus_id. 387 388 @raises: USBDeviceDriversManagerError if device bus ID for this instance 389 has not been set yet. 390 391 """ 392 if self._device_bus_id is None: 393 raise USBDeviceDriversManagerError('USB Bus ID is not set yet.') 394 if self.drivers_are_bound(): 395 return 396 utils.open_write_close(self._USB_BIND_FILE_PATH, 397 self._device_bus_id) 398 399 400 def unbind_usb_drivers(self): 401 """Unbinds the USB driver(s) of the current device from the host. 402 403 This is applied to all the drivers associated with and listed under 404 the USB device with the current _device_product_name and _device_bus_id. 405 406 @raises: USBDeviceDriversManagerError if device bus ID for this instance 407 has not been set yet. 408 409 """ 410 if self._device_bus_id is None: 411 raise USBDeviceDriversManagerError('USB Bus ID is not set yet.') 412 if not self.drivers_are_bound(): 413 return 414 utils.open_write_close(self._USB_UNBIND_FILE_PATH, 415 self._device_bus_id) 416