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