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 "usb.h" 22 #include "hcd.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 */ 109 if (i == 0 && desc && (is_rndis(desc) || is_activesync(desc))) { 110 #if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE) 111 continue; 112 #else 113 best = c; 114 #endif 115 } 116 117 /* From the remaining configs, choose the first one whose 118 * first interface is for a non-vendor-specific class. 119 * Reason: Linux is more likely to have a class driver 120 * than a vendor-specific driver. */ 121 else if (udev->descriptor.bDeviceClass != 122 USB_CLASS_VENDOR_SPEC && 123 (!desc || desc->bInterfaceClass != 124 USB_CLASS_VENDOR_SPEC)) { 125 best = c; 126 break; 127 } 128 129 /* If all the remaining configs are vendor-specific, 130 * choose the first one. */ 131 else if (!best) 132 best = c; 133 } 134 135 if (insufficient_power > 0) 136 dev_info(&udev->dev, "rejected %d configuration%s " 137 "due to insufficient available bus power\n", 138 insufficient_power, plural(insufficient_power)); 139 140 if (best) { 141 i = best->desc.bConfigurationValue; 142 dev_info(&udev->dev, 143 "configuration #%d chosen from %d choice%s\n", 144 i, num_configs, plural(num_configs)); 145 } else { 146 i = -1; 147 dev_warn(&udev->dev, 148 "no configuration chosen from %d choice%s\n", 149 num_configs, plural(num_configs)); 150 } 151 return i; 152 } 153 154 static int generic_probe(struct usb_device *udev) 155 { 156 int err, c; 157 158 /* Choose and set the configuration. This registers the interfaces 159 * with the driver core and lets interface drivers bind to them. 160 */ 161 if (udev->authorized == 0) 162 dev_err(&udev->dev, "Device is not authorized for usage\n"); 163 else { 164 c = usb_choose_configuration(udev); 165 if (c >= 0) { 166 err = usb_set_configuration(udev, c); 167 if (err) { 168 dev_err(&udev->dev, "can't set config #%d, error %d\n", 169 c, err); 170 /* This need not be fatal. The user can try to 171 * set other configurations. */ 172 } 173 } 174 } 175 /* USB device state == configured ... usable */ 176 usb_notify_add_device(udev); 177 178 return 0; 179 } 180 181 static void generic_disconnect(struct usb_device *udev) 182 { 183 usb_notify_remove_device(udev); 184 185 /* if this is only an unbind, not a physical disconnect, then 186 * unconfigure the device */ 187 if (udev->actconfig) 188 usb_set_configuration(udev, -1); 189 } 190 191 #ifdef CONFIG_PM 192 193 static int generic_suspend(struct usb_device *udev, pm_message_t msg) 194 { 195 int rc; 196 197 /* Normal USB devices suspend through their upstream port. 198 * Root hubs don't have upstream ports to suspend, 199 * so we have to shut down their downstream HC-to-USB 200 * interfaces manually by doing a bus (or "global") suspend. 201 */ 202 if (!udev->parent) 203 rc = hcd_bus_suspend(udev); 204 205 /* Non-root devices don't need to do anything for FREEZE or PRETHAW */ 206 else if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW) 207 rc = 0; 208 else 209 rc = usb_port_suspend(udev); 210 211 return rc; 212 } 213 214 static int generic_resume(struct usb_device *udev) 215 { 216 int rc; 217 218 /* Normal USB devices resume/reset through their upstream port. 219 * Root hubs don't have upstream ports to resume or reset, 220 * so we have to start up their downstream HC-to-USB 221 * interfaces manually by doing a bus (or "global") resume. 222 */ 223 if (!udev->parent) 224 rc = hcd_bus_resume(udev); 225 else 226 rc = usb_port_resume(udev); 227 return rc; 228 } 229 230 #endif /* CONFIG_PM */ 231 232 struct usb_device_driver usb_generic_driver = { 233 .name = "usb", 234 .probe = generic_probe, 235 .disconnect = generic_disconnect, 236 #ifdef CONFIG_PM 237 .suspend = generic_suspend, 238 .resume = generic_resume, 239 #endif 240 .supports_autosuspend = 1, 241 }; 242