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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/usb/core/generic.c - generic driver for USB devices (not interfaces)
4 *
5 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
6 *
7 * based on drivers/usb/usb.c which had the following copyrights:
8 * (C) Copyright Linus Torvalds 1999
9 * (C) Copyright Johannes Erdfelt 1999-2001
10 * (C) Copyright Andreas Gal 1999
11 * (C) Copyright Gregory P. Smith 1999
12 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
13 * (C) Copyright Randy Dunlap 2000
14 * (C) Copyright David Brownell 2000-2004
15 * (C) Copyright Yggdrasil Computing, Inc. 2000
16 * (usb_device_id matching changes by Adam J. Richter)
17 * (C) Copyright Greg Kroah-Hartman 2002-2003
18 *
19 * Released under the GPLv2 only.
20 */
21
22#include <linux/usb.h>
23#include <linux/usb/hcd.h>
24#include <uapi/linux/usb/audio.h>
25#include "usb.h"
26
27static inline const char *plural(int n)
28{
29 return (n == 1 ? "" : "s");
30}
31
32static int is_rndis(struct usb_interface_descriptor *desc)
33{
34 return desc->bInterfaceClass == USB_CLASS_COMM
35 && desc->bInterfaceSubClass == 2
36 && desc->bInterfaceProtocol == 0xff;
37}
38
39static int is_activesync(struct usb_interface_descriptor *desc)
40{
41 return desc->bInterfaceClass == USB_CLASS_MISC
42 && desc->bInterfaceSubClass == 1
43 && desc->bInterfaceProtocol == 1;
44}
45
46static bool is_audio(struct usb_interface_descriptor *desc)
47{
48 return desc->bInterfaceClass == USB_CLASS_AUDIO;
49}
50
51static bool is_uac3_config(struct usb_interface_descriptor *desc)
52{
53 return desc->bInterfaceProtocol == UAC_VERSION_3;
54}
55
56int usb_choose_configuration(struct usb_device *udev)
57{
58 int i;
59 int num_configs;
60 int insufficient_power = 0;
61 struct usb_host_config *c, *best;
62 struct usb_device_driver *udriver;
63
64 /*
65 * If a USB device (not an interface) doesn't have a driver then the
66 * kernel has no business trying to select or install a configuration
67 * for it.
68 */
69 if (!udev->dev.driver)
70 return -1;
71 udriver = to_usb_device_driver(udev->dev.driver);
72
73 if (usb_device_is_owned(udev))
74 return 0;
75
76 if (udriver->choose_configuration) {
77 i = udriver->choose_configuration(udev);
78 if (i >= 0)
79 return i;
80 }
81
82 best = NULL;
83 c = udev->config;
84 num_configs = udev->descriptor.bNumConfigurations;
85 for (i = 0; i < num_configs; (i++, c++)) {
86 struct usb_interface_descriptor *desc = NULL;
87
88 /* It's possible that a config has no interfaces! */
89 if (c->desc.bNumInterfaces > 0)
90 desc = &c->intf_cache[0]->altsetting->desc;
91
92 /*
93 * HP's USB bus-powered keyboard has only one configuration
94 * and it claims to be self-powered; other devices may have
95 * similar errors in their descriptors. If the next test
96 * were allowed to execute, such configurations would always
97 * be rejected and the devices would not work as expected.
98 * In the meantime, we run the risk of selecting a config
99 * that requires external power at a time when that power
100 * isn't available. It seems to be the lesser of two evils.
101 *
102 * Bugzilla #6448 reports a device that appears to crash
103 * when it receives a GET_DEVICE_STATUS request! We don't
104 * have any other way to tell whether a device is self-powered,
105 * but since we don't use that information anywhere but here,
106 * the call has been removed.
107 *
108 * Maybe the GET_DEVICE_STATUS call and the test below can
109 * be reinstated when device firmwares become more reliable.
110 * Don't hold your breath.
111 */
112#if 0
113 /* Rule out self-powered configs for a bus-powered device */
114 if (bus_powered && (c->desc.bmAttributes &
115 USB_CONFIG_ATT_SELFPOWER))
116 continue;
117#endif
118
119 /*
120 * The next test may not be as effective as it should be.
121 * Some hubs have errors in their descriptor, claiming
122 * to be self-powered when they are really bus-powered.
123 * We will overestimate the amount of current such hubs
124 * make available for each port.
125 *
126 * This is a fairly benign sort of failure. It won't
127 * cause us to reject configurations that we should have
128 * accepted.
129 */
130
131 /* Rule out configs that draw too much bus current */
132 if (usb_get_max_power(udev, c) > udev->bus_mA) {
133 insufficient_power++;
134 continue;
135 }
136
137 /*
138 * Select first configuration as default for audio so that
139 * devices that don't comply with UAC3 protocol are supported.
140 * But, still iterate through other configurations and
141 * select UAC3 compliant config if present.
142 */
143 if (desc && is_audio(desc)) {
144 /* Always prefer the first found UAC3 config */
145 if (is_uac3_config(desc)) {
146 best = c;
147 break;
148 }
149
150 /* If there is no UAC3 config, prefer the first config */
151 else if (i == 0)
152 best = c;
153
154 /* Unconditional continue, because the rest of the code
155 * in the loop is irrelevant for audio devices, and
156 * because it can reassign best, which for audio devices
157 * we don't want.
158 */
159 continue;
160 }
161
162 /* When the first config's first interface is one of Microsoft's
163 * pet nonstandard Ethernet-over-USB protocols, ignore it unless
164 * this kernel has enabled the necessary host side driver.
165 * But: Don't ignore it if it's the only config.
166 */
167 if (i == 0 && num_configs > 1 && desc &&
168 (is_rndis(desc) || is_activesync(desc))) {
169#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
170 continue;
171#else
172 best = c;
173#endif
174 }
175
176 /* From the remaining configs, choose the first one whose
177 * first interface is for a non-vendor-specific class.
178 * Reason: Linux is more likely to have a class driver
179 * than a vendor-specific driver. */
180 else if (udev->descriptor.bDeviceClass !=
181 USB_CLASS_VENDOR_SPEC &&
182 (desc && desc->bInterfaceClass !=
183 USB_CLASS_VENDOR_SPEC)) {
184 best = c;
185 break;
186 }
187
188 /* If all the remaining configs are vendor-specific,
189 * choose the first one. */
190 else if (!best)
191 best = c;
192 }
193
194 if (insufficient_power > 0)
195 dev_info(&udev->dev, "rejected %d configuration%s "
196 "due to insufficient available bus power\n",
197 insufficient_power, plural(insufficient_power));
198
199 if (best) {
200 i = best->desc.bConfigurationValue;
201 dev_dbg(&udev->dev,
202 "configuration #%d chosen from %d choice%s\n",
203 i, num_configs, plural(num_configs));
204 } else {
205 i = -1;
206 dev_warn(&udev->dev,
207 "no configuration chosen from %d choice%s\n",
208 num_configs, plural(num_configs));
209 }
210 return i;
211}
212EXPORT_SYMBOL_GPL(usb_choose_configuration);
213
214static int __check_for_non_generic_match(struct device_driver *drv, void *data)
215{
216 struct usb_device *udev = data;
217 struct usb_device_driver *udrv;
218
219 if (!is_usb_device_driver(drv))
220 return 0;
221 udrv = to_usb_device_driver(drv);
222 if (udrv == &usb_generic_driver)
223 return 0;
224 return usb_driver_applicable(udev, udrv);
225}
226
227static bool usb_generic_driver_match(struct usb_device *udev)
228{
229 if (udev->use_generic_driver)
230 return true;
231
232 /*
233 * If any other driver wants the device, leave the device to this other
234 * driver.
235 */
236 if (bus_for_each_drv(&usb_bus_type, NULL, udev, __check_for_non_generic_match))
237 return false;
238
239 return true;
240}
241
242int usb_generic_driver_probe(struct usb_device *udev)
243{
244 int err, c;
245
246 /* Choose and set the configuration. This registers the interfaces
247 * with the driver core and lets interface drivers bind to them.
248 */
249 if (udev->authorized == 0)
250 dev_err(&udev->dev, "Device is not authorized for usage\n");
251 else {
252 c = usb_choose_configuration(udev);
253 if (c >= 0) {
254 err = usb_set_configuration(udev, c);
255 if (err && err != -ENODEV) {
256 dev_err(&udev->dev, "can't set config #%d, error %d\n",
257 c, err);
258 /* This need not be fatal. The user can try to
259 * set other configurations. */
260 }
261 }
262 }
263 /* USB device state == configured ... usable */
264 usb_notify_add_device(udev);
265
266 return 0;
267}
268
269void usb_generic_driver_disconnect(struct usb_device *udev)
270{
271 usb_notify_remove_device(udev);
272
273 /* if this is only an unbind, not a physical disconnect, then
274 * unconfigure the device */
275 if (udev->actconfig)
276 usb_set_configuration(udev, -1);
277}
278
279#ifdef CONFIG_PM
280
281int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg)
282{
283 int rc;
284
285 /* Normal USB devices suspend through their upstream port.
286 * Root hubs don't have upstream ports to suspend,
287 * so we have to shut down their downstream HC-to-USB
288 * interfaces manually by doing a bus (or "global") suspend.
289 */
290 if (!udev->parent)
291 rc = hcd_bus_suspend(udev, msg);
292
293 /*
294 * Non-root USB2 devices don't need to do anything for FREEZE
295 * or PRETHAW. USB3 devices don't support global suspend and
296 * needs to be selectively suspended.
297 */
298 else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
299 && (udev->speed < USB_SPEED_SUPER))
300 rc = 0;
301 else
302 rc = usb_port_suspend(udev, msg);
303
304 if (rc == 0)
305 usbfs_notify_suspend(udev);
306 return rc;
307}
308
309int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg)
310{
311 int rc;
312
313 /* Normal USB devices resume/reset through their upstream port.
314 * Root hubs don't have upstream ports to resume or reset,
315 * so we have to start up their downstream HC-to-USB
316 * interfaces manually by doing a bus (or "global") resume.
317 */
318 if (!udev->parent)
319 rc = hcd_bus_resume(udev, msg);
320 else
321 rc = usb_port_resume(udev, msg);
322
323 if (rc == 0)
324 usbfs_notify_resume(udev);
325 return rc;
326}
327
328#endif /* CONFIG_PM */
329
330struct usb_device_driver usb_generic_driver = {
331 .name = "usb",
332 .match = usb_generic_driver_match,
333 .probe = usb_generic_driver_probe,
334 .disconnect = usb_generic_driver_disconnect,
335#ifdef CONFIG_PM
336 .suspend = usb_generic_driver_suspend,
337 .resume = usb_generic_driver_resume,
338#endif
339 .supports_autosuspend = 1,
340};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/usb/generic.c - generic driver for USB devices (not interfaces)
4 *
5 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
6 *
7 * based on drivers/usb/usb.c which had the following copyrights:
8 * (C) Copyright Linus Torvalds 1999
9 * (C) Copyright Johannes Erdfelt 1999-2001
10 * (C) Copyright Andreas Gal 1999
11 * (C) Copyright Gregory P. Smith 1999
12 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
13 * (C) Copyright Randy Dunlap 2000
14 * (C) Copyright David Brownell 2000-2004
15 * (C) Copyright Yggdrasil Computing, Inc. 2000
16 * (usb_device_id matching changes by Adam J. Richter)
17 * (C) Copyright Greg Kroah-Hartman 2002-2003
18 *
19 * Released under the GPLv2 only.
20 */
21
22#include <linux/usb.h>
23#include <linux/usb/hcd.h>
24#include "usb.h"
25
26static inline const char *plural(int n)
27{
28 return (n == 1 ? "" : "s");
29}
30
31static int is_rndis(struct usb_interface_descriptor *desc)
32{
33 return desc->bInterfaceClass == USB_CLASS_COMM
34 && desc->bInterfaceSubClass == 2
35 && desc->bInterfaceProtocol == 0xff;
36}
37
38static int is_activesync(struct usb_interface_descriptor *desc)
39{
40 return desc->bInterfaceClass == USB_CLASS_MISC
41 && desc->bInterfaceSubClass == 1
42 && desc->bInterfaceProtocol == 1;
43}
44
45int usb_choose_configuration(struct usb_device *udev)
46{
47 int i;
48 int num_configs;
49 int insufficient_power = 0;
50 struct usb_host_config *c, *best;
51
52 if (usb_device_is_owned(udev))
53 return 0;
54
55 best = NULL;
56 c = udev->config;
57 num_configs = udev->descriptor.bNumConfigurations;
58 for (i = 0; i < num_configs; (i++, c++)) {
59 struct usb_interface_descriptor *desc = NULL;
60
61 /* It's possible that a config has no interfaces! */
62 if (c->desc.bNumInterfaces > 0)
63 desc = &c->intf_cache[0]->altsetting->desc;
64
65 /*
66 * HP's USB bus-powered keyboard has only one configuration
67 * and it claims to be self-powered; other devices may have
68 * similar errors in their descriptors. If the next test
69 * were allowed to execute, such configurations would always
70 * be rejected and the devices would not work as expected.
71 * In the meantime, we run the risk of selecting a config
72 * that requires external power at a time when that power
73 * isn't available. It seems to be the lesser of two evils.
74 *
75 * Bugzilla #6448 reports a device that appears to crash
76 * when it receives a GET_DEVICE_STATUS request! We don't
77 * have any other way to tell whether a device is self-powered,
78 * but since we don't use that information anywhere but here,
79 * the call has been removed.
80 *
81 * Maybe the GET_DEVICE_STATUS call and the test below can
82 * be reinstated when device firmwares become more reliable.
83 * Don't hold your breath.
84 */
85#if 0
86 /* Rule out self-powered configs for a bus-powered device */
87 if (bus_powered && (c->desc.bmAttributes &
88 USB_CONFIG_ATT_SELFPOWER))
89 continue;
90#endif
91
92 /*
93 * The next test may not be as effective as it should be.
94 * Some hubs have errors in their descriptor, claiming
95 * to be self-powered when they are really bus-powered.
96 * We will overestimate the amount of current such hubs
97 * make available for each port.
98 *
99 * This is a fairly benign sort of failure. It won't
100 * cause us to reject configurations that we should have
101 * accepted.
102 */
103
104 /* Rule out configs that draw too much bus current */
105 if (usb_get_max_power(udev, c) > udev->bus_mA) {
106 insufficient_power++;
107 continue;
108 }
109
110 /* When the first config's first interface is one of Microsoft's
111 * pet nonstandard Ethernet-over-USB protocols, ignore it unless
112 * this kernel has enabled the necessary host side driver.
113 * But: Don't ignore it if it's the only config.
114 */
115 if (i == 0 && num_configs > 1 && desc &&
116 (is_rndis(desc) || is_activesync(desc))) {
117#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
118 continue;
119#else
120 best = c;
121#endif
122 }
123
124 /* From the remaining configs, choose the first one whose
125 * first interface is for a non-vendor-specific class.
126 * Reason: Linux is more likely to have a class driver
127 * than a vendor-specific driver. */
128 else if (udev->descriptor.bDeviceClass !=
129 USB_CLASS_VENDOR_SPEC &&
130 (desc && desc->bInterfaceClass !=
131 USB_CLASS_VENDOR_SPEC)) {
132 best = c;
133 break;
134 }
135
136 /* If all the remaining configs are vendor-specific,
137 * choose the first one. */
138 else if (!best)
139 best = c;
140 }
141
142 if (insufficient_power > 0)
143 dev_info(&udev->dev, "rejected %d configuration%s "
144 "due to insufficient available bus power\n",
145 insufficient_power, plural(insufficient_power));
146
147 if (best) {
148 i = best->desc.bConfigurationValue;
149 dev_dbg(&udev->dev,
150 "configuration #%d chosen from %d choice%s\n",
151 i, num_configs, plural(num_configs));
152 } else {
153 i = -1;
154 dev_warn(&udev->dev,
155 "no configuration chosen from %d choice%s\n",
156 num_configs, plural(num_configs));
157 }
158 return i;
159}
160EXPORT_SYMBOL_GPL(usb_choose_configuration);
161
162static int generic_probe(struct usb_device *udev)
163{
164 int err, c;
165
166 /* Choose and set the configuration. This registers the interfaces
167 * with the driver core and lets interface drivers bind to them.
168 */
169 if (udev->authorized == 0)
170 dev_err(&udev->dev, "Device is not authorized for usage\n");
171 else {
172 c = usb_choose_configuration(udev);
173 if (c >= 0) {
174 err = usb_set_configuration(udev, c);
175 if (err && err != -ENODEV) {
176 dev_err(&udev->dev, "can't set config #%d, error %d\n",
177 c, err);
178 /* This need not be fatal. The user can try to
179 * set other configurations. */
180 }
181 }
182 }
183 /* USB device state == configured ... usable */
184 usb_notify_add_device(udev);
185
186 return 0;
187}
188
189static void generic_disconnect(struct usb_device *udev)
190{
191 usb_notify_remove_device(udev);
192
193 /* if this is only an unbind, not a physical disconnect, then
194 * unconfigure the device */
195 if (udev->actconfig)
196 usb_set_configuration(udev, -1);
197}
198
199#ifdef CONFIG_PM
200
201static int generic_suspend(struct usb_device *udev, pm_message_t msg)
202{
203 int rc;
204
205 /* Normal USB devices suspend through their upstream port.
206 * Root hubs don't have upstream ports to suspend,
207 * so we have to shut down their downstream HC-to-USB
208 * interfaces manually by doing a bus (or "global") suspend.
209 */
210 if (!udev->parent)
211 rc = hcd_bus_suspend(udev, msg);
212
213 /*
214 * Non-root USB2 devices don't need to do anything for FREEZE
215 * or PRETHAW. USB3 devices don't support global suspend and
216 * needs to be selectively suspended.
217 */
218 else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
219 && (udev->speed < USB_SPEED_SUPER))
220 rc = 0;
221 else
222 rc = usb_port_suspend(udev, msg);
223
224 return rc;
225}
226
227static int generic_resume(struct usb_device *udev, pm_message_t msg)
228{
229 int rc;
230
231 /* Normal USB devices resume/reset through their upstream port.
232 * Root hubs don't have upstream ports to resume or reset,
233 * so we have to start up their downstream HC-to-USB
234 * interfaces manually by doing a bus (or "global") resume.
235 */
236 if (!udev->parent)
237 rc = hcd_bus_resume(udev, msg);
238 else
239 rc = usb_port_resume(udev, msg);
240 return rc;
241}
242
243#endif /* CONFIG_PM */
244
245struct usb_device_driver usb_generic_driver = {
246 .name = "usb",
247 .probe = generic_probe,
248 .disconnect = generic_disconnect,
249#ifdef CONFIG_PM
250 .suspend = generic_suspend,
251 .resume = generic_resume,
252#endif
253 .supports_autosuspend = 1,
254};