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 24static inline const char *plural(int n) 25{ 26 return (n == 1 ? "" : "s"); 27} 28 29static 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 36static 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 43int 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 81 /* 82 * The next test may not be as effective as it should be. 83 * Some hubs have errors in their descriptor, claiming 84 * to be self-powered when they are really bus-powered. 85 * We will overestimate the amount of current such hubs 86 * make available for each port. 87 * 88 * This is a fairly benign sort of failure. It won't 89 * cause us to reject configurations that we should have 90 * accepted. 91 */ 92 93 /* Rule out configs that draw too much bus current */ 94 if (c->desc.bMaxPower * 2 > udev->bus_mA) { 95 insufficient_power++; 96 continue; 97 } 98 99 /* When the first config's first interface is one of Microsoft's 100 * pet nonstandard Ethernet-over-USB protocols, ignore it unless 101 * this kernel has enabled the necessary host side driver. 102 * But: Don't ignore it if it's the only config. 103 */ 104 if (i == 0 && num_configs > 1 && desc && 105 (is_rndis(desc) || is_activesync(desc))) { 106#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE) 107 continue; 108#else 109 best = c; 110#endif 111 } 112 113 /* From the remaining configs, choose the first one whose 114 * first interface is for a non-vendor-specific class. 115 * Reason: Linux is more likely to have a class driver 116 * than a vendor-specific driver. */ 117 else if (udev->descriptor.bDeviceClass != 118 USB_CLASS_VENDOR_SPEC && 119 (desc && desc->bInterfaceClass != 120 USB_CLASS_VENDOR_SPEC)) { 121 best = c; 122 break; 123 } 124 125 /* If all the remaining configs are vendor-specific, 126 * choose the first one. */ 127 else if (!best) 128 best = c; 129 } 130 131 if (insufficient_power > 0) 132 dev_info(&udev->dev, "rejected %d configuration%s " 133 "due to insufficient available bus power\n", 134 insufficient_power, plural(insufficient_power)); 135 136 if (best) { 137 i = best->desc.bConfigurationValue; 138 dev_dbg(&udev->dev, 139 "configuration #%d chosen from %d choice%s\n", 140 i, num_configs, plural(num_configs)); 141 } else { 142 i = -1; 143 dev_warn(&udev->dev, 144 "no configuration chosen from %d choice%s\n", 145 num_configs, plural(num_configs)); 146 } 147 return i; 148} 149 150static int generic_probe(struct usb_device *udev) 151{ 152 int err, c; 153 154 /* Choose and set the configuration. This registers the interfaces 155 * with the driver core and lets interface drivers bind to them. 156 */ 157 if (usb_device_is_owned(udev)) 158 ; /* Don't configure if the device is owned */ 159 else if (udev->authorized == 0) 160 dev_err(&udev->dev, "Device is not authorized for usage\n"); 161 else { 162 c = usb_choose_configuration(udev); 163 if (c >= 0) { 164 err = usb_set_configuration(udev, c); 165 if (err) { 166 dev_err(&udev->dev, "can't set config #%d, error %d\n", 167 c, err); 168 /* This need not be fatal. The user can try to 169 * set other configurations. */ 170 } 171 } 172 } 173 /* USB device state == configured ... usable */ 174 usb_notify_add_device(udev); 175 176 return 0; 177} 178 179static void generic_disconnect(struct usb_device *udev) 180{ 181 usb_notify_remove_device(udev); 182 183 /* if this is only an unbind, not a physical disconnect, then 184 * unconfigure the device */ 185 if (udev->actconfig) 186 usb_set_configuration(udev, -1); 187} 188 189#ifdef CONFIG_PM 190 191static int generic_suspend(struct usb_device *udev, pm_message_t msg) 192{ 193 int rc; 194 195 /* Normal USB devices suspend through their upstream port. 196 * Root hubs don't have upstream ports to suspend, 197 * so we have to shut down their downstream HC-to-USB 198 * interfaces manually by doing a bus (or "global") suspend. 199 */ 200 if (!udev->parent) 201 rc = hcd_bus_suspend(udev, msg); 202 203 /* Non-root devices don't need to do anything for FREEZE or PRETHAW */ 204 else if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW) 205 rc = 0; 206 else 207 rc = usb_port_suspend(udev, msg); 208 209 return rc; 210} 211 212static int generic_resume(struct usb_device *udev, pm_message_t msg) 213{ 214 int rc; 215 216 /* Normal USB devices resume/reset through their upstream port. 217 * Root hubs don't have upstream ports to resume or reset, 218 * so we have to start up their downstream HC-to-USB 219 * interfaces manually by doing a bus (or "global") resume. 220 */ 221 if (!udev->parent) 222 rc = hcd_bus_resume(udev, msg); 223 else 224 rc = usb_port_resume(udev, msg); 225 return rc; 226} 227 228#endif /* CONFIG_PM */ 229 230struct usb_device_driver usb_generic_driver = { 231 .name = "usb", 232 .probe = generic_probe, 233 .disconnect = generic_disconnect, 234#ifdef CONFIG_PM 235 .suspend = generic_suspend, 236 .resume = generic_resume, 237#endif 238 .supports_autosuspend = 1, 239}; 240