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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 : 0 : return (n == 1 ? "" : "s"); 30 : : } 31 : : 32 : : static int is_rndis(struct usb_interface_descriptor *desc) 33 : : { 34 : 1 : return desc->bInterfaceClass == USB_CLASS_COMM 35 : 1 : && desc->bInterfaceSubClass == 2 36 : 1 : && desc->bInterfaceProtocol == 0xff; 37 : : } 38 : : 39 : : static int is_activesync(struct usb_interface_descriptor *desc) 40 : : { 41 : : return desc->bInterfaceClass == USB_CLASS_MISC 42 : 0 : && desc->bInterfaceSubClass == 1 43 : 0 : && desc->bInterfaceProtocol == 1; 44 : : } 45 : : 46 : : static bool is_audio(struct usb_interface_descriptor *desc) 47 : : { 48 : 3 : return desc->bInterfaceClass == USB_CLASS_AUDIO; 49 : : } 50 : : 51 : : static bool is_uac3_config(struct usb_interface_descriptor *desc) 52 : : { 53 : 0 : return desc->bInterfaceProtocol == UAC_VERSION_3; 54 : : } 55 : : 56 : 3 : 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 : 3 : if (usb_device_is_owned(udev)) 64 : : return 0; 65 : : 66 : : best = NULL; 67 : 3 : c = udev->config; 68 : 3 : num_configs = udev->descriptor.bNumConfigurations; 69 : 3 : 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 : 3 : if (c->desc.bNumInterfaces > 0) 74 : 3 : 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 : 3 : if (usb_get_max_power(udev, c) > udev->bus_mA) { 117 : 0 : insufficient_power++; 118 : 0 : 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 : 3 : if (desc && is_audio(desc)) { 128 : : /* Always prefer the first found UAC3 config */ 129 : 0 : if (is_uac3_config(desc)) { 130 : 0 : best = c; 131 : 0 : break; 132 : : } 133 : : 134 : : /* If there is no UAC3 config, prefer the first config */ 135 : 0 : 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 : 0 : 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 : 3 : if (i == 0 && num_configs > 1 && desc && 152 : 0 : (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 : 3 : else if (udev->descriptor.bDeviceClass != 165 : 3 : USB_CLASS_VENDOR_SPEC && 166 : 3 : (desc && desc->bInterfaceClass != 167 : : USB_CLASS_VENDOR_SPEC)) { 168 : 3 : best = c; 169 : 3 : break; 170 : : } 171 : : 172 : : /* If all the remaining configs are vendor-specific, 173 : : * choose the first one. */ 174 : 2 : else if (!best) 175 : : best = c; 176 : : } 177 : : 178 : 3 : if (insufficient_power > 0) 179 : 0 : dev_info(&udev->dev, "rejected %d configuration%s " 180 : : "due to insufficient available bus power\n", 181 : : insufficient_power, plural(insufficient_power)); 182 : : 183 : 3 : if (best) { 184 : 3 : 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 : 0 : dev_warn(&udev->dev, 191 : : "no configuration chosen from %d choice%s\n", 192 : : num_configs, plural(num_configs)); 193 : 0 : dev_warn(&udev->dev, "No support over %dmA\n", udev->bus_mA); 194 : : } 195 : 3 : return i; 196 : : } 197 : : EXPORT_SYMBOL_GPL(usb_choose_configuration); 198 : : 199 : 3 : static int generic_probe(struct usb_device *udev) 200 : : { 201 : : int err, c; 202 : : 203 : : /* Choose and set the configuration. This registers the interfaces 204 : : * with the driver core and lets interface drivers bind to them. 205 : : */ 206 : 3 : if (udev->authorized == 0) 207 : 0 : dev_err(&udev->dev, "Device is not authorized for usage\n"); 208 : : else { 209 : 3 : c = usb_choose_configuration(udev); 210 : 3 : if (c >= 0) { 211 : 3 : err = usb_set_configuration(udev, c); 212 : 3 : if (err && err != -ENODEV) { 213 : 0 : dev_err(&udev->dev, "can't set config #%d, error %d\n", 214 : : c, err); 215 : : /* This need not be fatal. The user can try to 216 : : * set other configurations. */ 217 : : } 218 : : } 219 : : } 220 : : /* USB device state == configured ... usable */ 221 : 3 : usb_notify_add_device(udev); 222 : : 223 : 3 : return 0; 224 : : } 225 : : 226 : 0 : static void generic_disconnect(struct usb_device *udev) 227 : : { 228 : 0 : usb_notify_remove_device(udev); 229 : : 230 : : /* if this is only an unbind, not a physical disconnect, then 231 : : * unconfigure the device */ 232 : 0 : if (udev->actconfig) 233 : 0 : usb_set_configuration(udev, -1); 234 : 0 : } 235 : : 236 : : #ifdef CONFIG_PM 237 : : 238 : 0 : static int generic_suspend(struct usb_device *udev, pm_message_t msg) 239 : : { 240 : : int rc; 241 : : 242 : : /* Normal USB devices suspend through their upstream port. 243 : : * Root hubs don't have upstream ports to suspend, 244 : : * so we have to shut down their downstream HC-to-USB 245 : : * interfaces manually by doing a bus (or "global") suspend. 246 : : */ 247 : 0 : if (!udev->parent) 248 : 0 : rc = hcd_bus_suspend(udev, msg); 249 : : 250 : : /* 251 : : * Non-root USB2 devices don't need to do anything for FREEZE 252 : : * or PRETHAW. USB3 devices don't support global suspend and 253 : : * needs to be selectively suspended. 254 : : */ 255 : 0 : else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW) 256 : 0 : && (udev->speed < USB_SPEED_SUPER)) 257 : : rc = 0; 258 : : else 259 : 0 : rc = usb_port_suspend(udev, msg); 260 : : 261 : 0 : if (rc == 0) 262 : 0 : usbfs_notify_suspend(udev); 263 : 0 : return rc; 264 : : } 265 : : 266 : 0 : static int generic_resume(struct usb_device *udev, pm_message_t msg) 267 : : { 268 : : int rc; 269 : : 270 : : /* Normal USB devices resume/reset through their upstream port. 271 : : * Root hubs don't have upstream ports to resume or reset, 272 : : * so we have to start up their downstream HC-to-USB 273 : : * interfaces manually by doing a bus (or "global") resume. 274 : : */ 275 : 0 : if (!udev->parent) 276 : 0 : rc = hcd_bus_resume(udev, msg); 277 : : else 278 : 0 : rc = usb_port_resume(udev, msg); 279 : : 280 : 0 : if (rc == 0) 281 : 0 : usbfs_notify_resume(udev); 282 : 0 : return rc; 283 : : } 284 : : 285 : : #endif /* CONFIG_PM */ 286 : : 287 : : struct usb_device_driver usb_generic_driver = { 288 : : .name = "usb", 289 : : .probe = generic_probe, 290 : : .disconnect = generic_disconnect, 291 : : #ifdef CONFIG_PM 292 : : .suspend = generic_suspend, 293 : : .resume = generic_resume, 294 : : #endif 295 : : .supports_autosuspend = 1, 296 : : };