drivers/usb/core/generic.c

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