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 27static inline const char *plural(int n) 28{ 29 return (n == 1 ? "" : "s"); 30} 31 32static 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 39static 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 46static bool is_audio(struct usb_interface_descriptor *desc) 47{ 48 return desc->bInterfaceClass == USB_CLASS_AUDIO; 49} 50 51static bool is_uac3_config(struct usb_interface_descriptor *desc) 52{ 53 return desc->bInterfaceProtocol == UAC_VERSION_3; 54} 55 56int 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} 212EXPORT_SYMBOL_GPL(usb_choose_configuration); 213 214static 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 227static 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 242int 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 269void 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 281int 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 309int 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 330struct 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}; 341