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, msg);
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, msg);
210
211 return rc;
212 }
213
214 static int generic_resume(struct usb_device *udev, pm_message_t msg)
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, msg);
225 else
226 rc = usb_port_resume(udev, msg);
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
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