1 /* 2 * drivers/usb/generic.c - generic driver for USB devices (not interfaces) 3 * 4 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de> 5 * 6 * based on drivers/usb/usb.c which had the following copyrights: 7 * (C) Copyright Linus Torvalds 1999 8 * (C) Copyright Johannes Erdfelt 1999-2001 9 * (C) Copyright Andreas Gal 1999 10 * (C) Copyright Gregory P. Smith 1999 11 * (C) Copyright Deti Fliegl 1999 (new USB architecture) 12 * (C) Copyright Randy Dunlap 2000 13 * (C) Copyright David Brownell 2000-2004 14 * (C) Copyright Yggdrasil Computing, Inc. 2000 15 * (usb_device_id matching changes by Adam J. Richter) 16 * (C) Copyright Greg Kroah-Hartman 2002-2003 17 * 18 */ 19 20 #include <linux/usb.h> 21 #include <linux/usb/hcd.h> 22 #include "usb.h" 23 24 static inline const char *plural(int n) 25 { 26 return (n == 1 ? "" : "s"); 27 } 28 29 static int is_rndis(struct usb_interface_descriptor *desc) 30 { 31 return desc->bInterfaceClass == USB_CLASS_COMM 32 && desc->bInterfaceSubClass == 2 33 && desc->bInterfaceProtocol == 0xff; 34 } 35 36 static int is_activesync(struct usb_interface_descriptor *desc) 37 { 38 return desc->bInterfaceClass == USB_CLASS_MISC 39 && desc->bInterfaceSubClass == 1 40 && desc->bInterfaceProtocol == 1; 41 } 42 43 int usb_choose_configuration(struct usb_device *udev) 44 { 45 int i; 46 int num_configs; 47 int insufficient_power = 0; 48 struct usb_host_config *c, *best; 49 50 if (usb_device_is_owned(udev)) 51 return 0; 52 53 best = NULL; 54 c = udev->config; 55 num_configs = udev->descriptor.bNumConfigurations; 56 for (i = 0; i < num_configs; (i++, c++)) { 57 struct usb_interface_descriptor *desc = NULL; 58 59 /* It's possible that a config has no interfaces! */ 60 if (c->desc.bNumInterfaces > 0) 61 desc = &c->intf_cache[0]->altsetting->desc; 62 63 /* 64 * HP's USB bus-powered keyboard has only one configuration 65 * and it claims to be self-powered; other devices may have 66 * similar errors in their descriptors. If the next test 67 * were allowed to execute, such configurations would always 68 * be rejected and the devices would not work as expected. 69 * In the meantime, we run the risk of selecting a config 70 * that requires external power at a time when that power 71 * isn't available. It seems to be the lesser of two evils. 72 * 73 * Bugzilla #6448 reports a device that appears to crash 74 * when it receives a GET_DEVICE_STATUS request! We don't 75 * have any other way to tell whether a device is self-powered, 76 * but since we don't use that information anywhere but here, 77 * the call has been removed. 78 * 79 * Maybe the GET_DEVICE_STATUS call and the test below can 80 * be reinstated when device firmwares become more reliable. 81 * Don't hold your breath. 82 */ 83 #if 0 84 /* Rule out self-powered configs for a bus-powered device */ 85 if (bus_powered && (c->desc.bmAttributes & 86 USB_CONFIG_ATT_SELFPOWER)) 87 continue; 88 #endif 89 90 /* 91 * The next test may not be as effective as it should be. 92 * Some hubs have errors in their descriptor, claiming 93 * to be self-powered when they are really bus-powered. 94 * We will overestimate the amount of current such hubs 95 * make available for each port. 96 * 97 * This is a fairly benign sort of failure. It won't 98 * cause us to reject configurations that we should have 99 * accepted. 100 */ 101 102 /* Rule out configs that draw too much bus current */ 103 if (usb_get_max_power(udev, c) > udev->bus_mA) { 104 insufficient_power++; 105 continue; 106 } 107 108 /* When the first config's first interface is one of Microsoft's 109 * pet nonstandard Ethernet-over-USB protocols, ignore it unless 110 * this kernel has enabled the necessary host side driver. 111 * But: Don't ignore it if it's the only config. 112 */ 113 if (i == 0 && num_configs > 1 && desc && 114 (is_rndis(desc) || is_activesync(desc))) { 115 #if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE) 116 continue; 117 #else 118 best = c; 119 #endif 120 } 121 122 /* From the remaining configs, choose the first one whose 123 * first interface is for a non-vendor-specific class. 124 * Reason: Linux is more likely to have a class driver 125 * than a vendor-specific driver. */ 126 else if (udev->descriptor.bDeviceClass != 127 USB_CLASS_VENDOR_SPEC && 128 (desc && desc->bInterfaceClass != 129 USB_CLASS_VENDOR_SPEC)) { 130 best = c; 131 break; 132 } 133 134 /* If all the remaining configs are vendor-specific, 135 * choose the first one. */ 136 else if (!best) 137 best = c; 138 } 139 140 if (insufficient_power > 0) 141 dev_info(&udev->dev, "rejected %d configuration%s " 142 "due to insufficient available bus power\n", 143 insufficient_power, plural(insufficient_power)); 144 145 if (best) { 146 i = best->desc.bConfigurationValue; 147 dev_dbg(&udev->dev, 148 "configuration #%d chosen from %d choice%s\n", 149 i, num_configs, plural(num_configs)); 150 } else { 151 i = -1; 152 dev_warn(&udev->dev, 153 "no configuration chosen from %d choice%s\n", 154 num_configs, plural(num_configs)); 155 } 156 return i; 157 } 158 EXPORT_SYMBOL_GPL(usb_choose_configuration); 159 160 static int generic_probe(struct usb_device *udev) 161 { 162 int err, c; 163 164 /* Choose and set the configuration. This registers the interfaces 165 * with the driver core and lets interface drivers bind to them. 166 */ 167 if (udev->authorized == 0) 168 dev_err(&udev->dev, "Device is not authorized for usage\n"); 169 else { 170 c = usb_choose_configuration(udev); 171 if (c >= 0) { 172 err = usb_set_configuration(udev, c); 173 if (err && err != -ENODEV) { 174 dev_err(&udev->dev, "can't set config #%d, error %d\n", 175 c, err); 176 /* This need not be fatal. The user can try to 177 * set other configurations. */ 178 } 179 } 180 } 181 /* USB device state == configured ... usable */ 182 usb_notify_add_device(udev); 183 184 return 0; 185 } 186 187 static void generic_disconnect(struct usb_device *udev) 188 { 189 usb_notify_remove_device(udev); 190 191 /* if this is only an unbind, not a physical disconnect, then 192 * unconfigure the device */ 193 if (udev->actconfig) 194 usb_set_configuration(udev, -1); 195 } 196 197 #ifdef CONFIG_PM 198 199 static int generic_suspend(struct usb_device *udev, pm_message_t msg) 200 { 201 int rc; 202 203 /* Normal USB devices suspend through their upstream port. 204 * Root hubs don't have upstream ports to suspend, 205 * so we have to shut down their downstream HC-to-USB 206 * interfaces manually by doing a bus (or "global") suspend. 207 */ 208 if (!udev->parent) 209 rc = hcd_bus_suspend(udev, msg); 210 211 /* Non-root devices don't need to do anything for FREEZE or PRETHAW */ 212 else if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW) 213 rc = 0; 214 else 215 rc = usb_port_suspend(udev, msg); 216 217 return rc; 218 } 219 220 static int generic_resume(struct usb_device *udev, pm_message_t msg) 221 { 222 int rc; 223 224 /* Normal USB devices resume/reset through their upstream port. 225 * Root hubs don't have upstream ports to resume or reset, 226 * so we have to start up their downstream HC-to-USB 227 * interfaces manually by doing a bus (or "global") resume. 228 */ 229 if (!udev->parent) 230 rc = hcd_bus_resume(udev, msg); 231 else 232 rc = usb_port_resume(udev, msg); 233 return rc; 234 } 235 236 #endif /* CONFIG_PM */ 237 238 struct usb_device_driver usb_generic_driver = { 239 .name = "usb", 240 .probe = generic_probe, 241 .disconnect = generic_disconnect, 242 #ifdef CONFIG_PM 243 .suspend = generic_suspend, 244 .resume = generic_resume, 245 #endif 246 .supports_autosuspend = 1, 247 }; 248