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