drivers/usb/core/generic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * drivers/usb/core/generic.c - generic driver for USB devices (not interfaces)
   4  *
   5  * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
   6  *
   7  * based on drivers/usb/usb.c which had the following copyrights:
   8  *      (C) Copyright Linus Torvalds 1999
   9  *      (C) Copyright Johannes Erdfelt 1999-2001
  10  *      (C) Copyright Andreas Gal 1999
  11  *      (C) Copyright Gregory P. Smith 1999
  12  *      (C) Copyright Deti Fliegl 1999 (new USB architecture)
  13  *      (C) Copyright Randy Dunlap 2000
  14  *      (C) Copyright David Brownell 2000-2004
  15  *      (C) Copyright Yggdrasil Computing, Inc. 2000
  16  *              (usb_device_id matching changes by Adam J. Richter)
  17  *      (C) Copyright Greg Kroah-Hartman 2002-2003
  18  *
  19  * Released under the GPLv2 only.
  20  */
  21
  22 #include <linux/usb.h>
  23 #include <linux/usb/hcd.h>
  24 #include <uapi/linux/usb/audio.h>
  25 #include "usb.h"
  26
  27 static inline const char *plural(int n)
  28 {
  29         return (n == 1 ? "" : "s");
  30 }
  31
  32 static int is_rndis(struct usb_interface_descriptor *desc)
  33 {
  34         return desc->bInterfaceClass == USB_CLASS_COMM
  35                 && desc->bInterfaceSubClass == 2
  36                 && desc->bInterfaceProtocol == 0xff;
  37 }
  38
  39 static int is_activesync(struct usb_interface_descriptor *desc)
  40 {
  41         return desc->bInterfaceClass == USB_CLASS_MISC
  42                 && desc->bInterfaceSubClass == 1
  43                 && desc->bInterfaceProtocol == 1;
  44 }
  45
  46 static bool is_audio(struct usb_interface_descriptor *desc)
  47 {
  48         return desc->bInterfaceClass == USB_CLASS_AUDIO;
  49 }
  50
  51 static bool is_uac3_config(struct usb_interface_descriptor *desc)
  52 {
  53         return desc->bInterfaceProtocol == UAC_VERSION_3;
  54 }
  55
  56 int usb_choose_configuration(struct usb_device *udev)
  57 {
  58         int i;
  59         int num_configs;
  60         int insufficient_power = 0;
  61         struct usb_host_config *c, *best;
  62         struct usb_device_driver *udriver;
  63
  64         /*
  65          * If a USB device (not an interface) doesn't have a driver then the
  66          * kernel has no business trying to select or install a configuration
  67          * for it.
  68          */
  69         if (!udev->dev.driver)
  70                 return -1;
  71         udriver = to_usb_device_driver(udev->dev.driver);
  72
  73         if (usb_device_is_owned(udev))
  74                 return 0;
  75
  76         if (udriver->choose_configuration) {
  77                 i = udriver->choose_configuration(udev);
  78                 if (i >= 0)
  79                         return i;
  80         }
  81
  82         best = NULL;
  83         c = udev->config;
  84         num_configs = udev->descriptor.bNumConfigurations;
  85         for (i = 0; i < num_configs; (i++, c++)) {
  86                 struct usb_interface_descriptor *desc = NULL;
  87
  88                 /* It's possible that a config has no interfaces! */
  89                 if (c->desc.bNumInterfaces > 0)
  90                         desc = &c->intf_cache[0]->altsetting->desc;
  91
  92                 /*
  93                  * HP's USB bus-powered keyboard has only one configuration
  94                  * and it claims to be self-powered; other devices may have
  95                  * similar errors in their descriptors.  If the next test
  96                  * were allowed to execute, such configurations would always
  97                  * be rejected and the devices would not work as expected.
  98                  * In the meantime, we run the risk of selecting a config
  99                  * that requires external power at a time when that power
 100                  * isn't available.  It seems to be the lesser of two evils.
 101                  *
 102                  * Bugzilla #6448 reports a device that appears to crash
 103                  * when it receives a GET_DEVICE_STATUS request!  We don't
 104                  * have any other way to tell whether a device is self-powered,
 105                  * but since we don't use that information anywhere but here,
 106                  * the call has been removed.
 107                  *
 108                  * Maybe the GET_DEVICE_STATUS call and the test below can
 109                  * be reinstated when device firmwares become more reliable.
 110                  * Don't hold your breath.
 111                  */
 112 #if 0
 113                 /* Rule out self-powered configs for a bus-powered device */
 114                 if (bus_powered && (c->desc.bmAttributes &
 115                                         USB_CONFIG_ATT_SELFPOWER))
 116                         continue;
 117 #endif
 118
 119                 /*
 120                  * The next test may not be as effective as it should be.
 121                  * Some hubs have errors in their descriptor, claiming
 122                  * to be self-powered when they are really bus-powered.
 123                  * We will overestimate the amount of current such hubs
 124                  * make available for each port.
 125                  *
 126                  * This is a fairly benign sort of failure.  It won't
 127                  * cause us to reject configurations that we should have
 128                  * accepted.
 129                  */
 130
 131                 /* Rule out configs that draw too much bus current */
 132                 if (usb_get_max_power(udev, c) > udev->bus_mA) {
 133                         insufficient_power++;
 134                         continue;
 135                 }
 136
 137                 /*
 138                  * Select first configuration as default for audio so that
 139                  * devices that don't comply with UAC3 protocol are supported.
 140                  * But, still iterate through other configurations and
 141                  * select UAC3 compliant config if present.
 142                  */
 143                 if (desc && is_audio(desc)) {
 144                         /* Always prefer the first found UAC3 config */
 145                         if (is_uac3_config(desc)) {
 146                                 best = c;
 147                                 break;
 148                         }
 149
 150                         /* If there is no UAC3 config, prefer the first config */
 151                         else if (i == 0)
 152                                 best = c;
 153
 154                         /* Unconditional continue, because the rest of the code
 155                          * in the loop is irrelevant for audio devices, and
 156                          * because it can reassign best, which for audio devices
 157                          * we don't want.
 158                          */
 159                         continue;
 160                 }
 161
 162                 /* When the first config's first interface is one of Microsoft's
 163                  * pet nonstandard Ethernet-over-USB protocols, ignore it unless
 164                  * this kernel has enabled the necessary host side driver.
 165                  * But: Don't ignore it if it's the only config.
 166                  */
 167                 if (i == 0 && num_configs > 1 && desc &&
 168                                 (is_rndis(desc) || is_activesync(desc))) {
 169 #if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
 170                         continue;
 171 #else
 172                         best = c;
 173 #endif
 174                 }
 175
 176                 /* From the remaining configs, choose the first one whose
 177                  * first interface is for a non-vendor-specific class.
 178                  * Reason: Linux is more likely to have a class driver
 179                  * than a vendor-specific driver. */
 180                 else if (udev->descriptor.bDeviceClass !=
 181                                                 USB_CLASS_VENDOR_SPEC &&
 182                                 (desc && desc->bInterfaceClass !=
 183                                                 USB_CLASS_VENDOR_SPEC)) {
 184                         best = c;
 185                         break;
 186                 }
 187
 188                 /* If all the remaining configs are vendor-specific,
 189                  * choose the first one. */
 190                 else if (!best)
 191                         best = c;
 192         }
 193
 194         if (insufficient_power > 0)
 195                 dev_info(&udev->dev, "rejected %d configuration%s "
 196                         "due to insufficient available bus power\n",
 197                         insufficient_power, plural(insufficient_power));
 198
 199         if (best) {
 200                 i = best->desc.bConfigurationValue;
 201                 dev_dbg(&udev->dev,
 202                         "configuration #%d chosen from %d choice%s\n",
 203                         i, num_configs, plural(num_configs));
 204         } else {
 205                 i = -1;
 206                 dev_warn(&udev->dev,
 207                         "no configuration chosen from %d choice%s\n",
 208                         num_configs, plural(num_configs));
 209         }
 210         return i;
 211 }
 212 EXPORT_SYMBOL_GPL(usb_choose_configuration);
 213
 214 static int __check_for_non_generic_match(struct device_driver *drv, void *data)
 215 {
 216         struct usb_device *udev = data;
 217         struct usb_device_driver *udrv;
 218
 219         if (!is_usb_device_driver(drv))
 220                 return 0;
 221         udrv = to_usb_device_driver(drv);
 222         if (udrv == &usb_generic_driver)
 223                 return 0;
 224         return usb_driver_applicable(udev, udrv);
 225 }
 226
 227 static bool usb_generic_driver_match(struct usb_device *udev)
 228 {
 229         if (udev->use_generic_driver)
 230                 return true;
 231
 232         /*
 233          * If any other driver wants the device, leave the device to this other
 234          * driver.
 235          */
 236         if (bus_for_each_drv(&usb_bus_type, NULL, udev, __check_for_non_generic_match))
 237                 return false;
 238
 239         return true;
 240 }
 241
 242 int usb_generic_driver_probe(struct usb_device *udev)
 243 {
 244         int err, c;
 245
 246         /* Choose and set the configuration.  This registers the interfaces
 247          * with the driver core and lets interface drivers bind to them.
 248          */
 249         if (udev->authorized == 0)
 250                 dev_err(&udev->dev, "Device is not authorized for usage\n");
 251         else {
 252                 c = usb_choose_configuration(udev);
 253                 if (c >= 0) {
 254                         err = usb_set_configuration(udev, c);
 255                         if (err && err != -ENODEV) {
 256                                 dev_err(&udev->dev, "can't set config #%d, error %d\n",
 257                                         c, err);
 258                                 /* This need not be fatal.  The user can try to
 259                                  * set other configurations. */
 260                         }
 261                 }
 262         }
 263         /* USB device state == configured ... usable */
 264         usb_notify_add_device(udev);
 265
 266         return 0;
 267 }
 268
 269 void usb_generic_driver_disconnect(struct usb_device *udev)
 270 {
 271         usb_notify_remove_device(udev);
 272
 273         /* if this is only an unbind, not a physical disconnect, then
 274          * unconfigure the device */
 275         if (udev->actconfig)
 276                 usb_set_configuration(udev, -1);
 277 }
 278
 279 #ifdef  CONFIG_PM
 280
 281 int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg)
 282 {
 283         int rc;
 284
 285         /* Normal USB devices suspend through their upstream port.
 286          * Root hubs don't have upstream ports to suspend,
 287          * so we have to shut down their downstream HC-to-USB
 288          * interfaces manually by doing a bus (or "global") suspend.
 289          */
 290         if (!udev->parent)
 291                 rc = hcd_bus_suspend(udev, msg);
 292
 293         /*
 294          * Non-root USB2 devices don't need to do anything for FREEZE
 295          * or PRETHAW. USB3 devices don't support global suspend and
 296          * needs to be selectively suspended.
 297          */
 298         else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
 299                  && (udev->speed < USB_SPEED_SUPER))
 300                 rc = 0;
 301         else
 302                 rc = usb_port_suspend(udev, msg);
 303
 304         if (rc == 0)
 305                 usbfs_notify_suspend(udev);
 306         return rc;
 307 }
 308
 309 int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg)
 310 {
 311         int rc;
 312
 313         /* Normal USB devices resume/reset through their upstream port.
 314          * Root hubs don't have upstream ports to resume or reset,
 315          * so we have to start up their downstream HC-to-USB
 316          * interfaces manually by doing a bus (or "global") resume.
 317          */
 318         if (!udev->parent)
 319                 rc = hcd_bus_resume(udev, msg);
 320         else
 321                 rc = usb_port_resume(udev, msg);
 322
 323         if (rc == 0)
 324                 usbfs_notify_resume(udev);
 325         return rc;
 326 }
 327
 328 #endif  /* CONFIG_PM */
 329
 330 struct usb_device_driver usb_generic_driver = {
 331         .name = "usb",
 332         .match = usb_generic_driver_match,
 333         .probe = usb_generic_driver_probe,
 334         .disconnect = usb_generic_driver_disconnect,
 335 #ifdef  CONFIG_PM
 336         .suspend = usb_generic_driver_suspend,
 337         .resume = usb_generic_driver_resume,
 338 #endif
 339         .supports_autosuspend = 1,
 340 };