summaryrefslogtreecommitdiff
path: root/drivers/usb/core/generic.c
blob: 22c887f5c49751e026c72ce19e2a35abb9100240 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/usb/generic.c - generic driver for USB devices (not interfaces)
 *
 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
 *
 * based on drivers/usb/usb.c which had the following copyrights:
 *	(C) Copyright Linus Torvalds 1999
 *	(C) Copyright Johannes Erdfelt 1999-2001
 *	(C) Copyright Andreas Gal 1999
 *	(C) Copyright Gregory P. Smith 1999
 *	(C) Copyright Deti Fliegl 1999 (new USB architecture)
 *	(C) Copyright Randy Dunlap 2000
 *	(C) Copyright David Brownell 2000-2004
 *	(C) Copyright Yggdrasil Computing, Inc. 2000
 *		(usb_device_id matching changes by Adam J. Richter)
 *	(C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * Released under the GPLv2 only.
 */

#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <uapi/linux/usb/audio.h>
#include "usb.h"

static inline const char *plural(int n)
{
	return (n == 1 ? "" : "s");
}

static int is_rndis(struct usb_interface_descriptor *desc)
{
	return desc->bInterfaceClass == USB_CLASS_COMM
		&& desc->bInterfaceSubClass == 2
		&& desc->bInterfaceProtocol == 0xff;
}

static int is_activesync(struct usb_interface_descriptor *desc)
{
	return desc->bInterfaceClass == USB_CLASS_MISC
		&& desc->bInterfaceSubClass == 1
		&& desc->bInterfaceProtocol == 1;
}

static bool is_audio(struct usb_interface_descriptor *desc)
{
	return desc->bInterfaceClass == USB_CLASS_AUDIO;
}

static bool is_uac3_config(struct usb_interface_descriptor *desc)
{
	return desc->bInterfaceProtocol == UAC_VERSION_3;
}

int usb_choose_configuration(struct usb_device *udev)
{
	int i;
	int num_configs;
	int insufficient_power = 0;
	struct usb_host_config *c, *best;

	if (usb_device_is_owned(udev))
		return 0;

	best = NULL;
	c = udev->config;
	num_configs = udev->descriptor.bNumConfigurations;
	for (i = 0; i < num_configs; (i++, c++)) {
		struct usb_interface_descriptor	*desc = NULL;

		/* It's possible that a config has no interfaces! */
		if (c->desc.bNumInterfaces > 0)
			desc = &c->intf_cache[0]->altsetting->desc;

		/*
		 * HP's USB bus-powered keyboard has only one configuration
		 * and it claims to be self-powered; other devices may have
		 * similar errors in their descriptors.  If the next test
		 * were allowed to execute, such configurations would always
		 * be rejected and the devices would not work as expected.
		 * In the meantime, we run the risk of selecting a config
		 * that requires external power at a time when that power
		 * isn't available.  It seems to be the lesser of two evils.
		 *
		 * Bugzilla #6448 reports a device that appears to crash
		 * when it receives a GET_DEVICE_STATUS request!  We don't
		 * have any other way to tell whether a device is self-powered,
		 * but since we don't use that information anywhere but here,
		 * the call has been removed.
		 *
		 * Maybe the GET_DEVICE_STATUS call and the test below can
		 * be reinstated when device firmwares become more reliable.
		 * Don't hold your breath.
		 */
#if 0
		/* Rule out self-powered configs for a bus-powered device */
		if (bus_powered && (c->desc.bmAttributes &
					USB_CONFIG_ATT_SELFPOWER))
			continue;
#endif

		/*
		 * The next test may not be as effective as it should be.
		 * Some hubs have errors in their descriptor, claiming
		 * to be self-powered when they are really bus-powered.
		 * We will overestimate the amount of current such hubs
		 * make available for each port.
		 *
		 * This is a fairly benign sort of failure.  It won't
		 * cause us to reject configurations that we should have
		 * accepted.
		 */

		/* Rule out configs that draw too much bus current */
		if (usb_get_max_power(udev, c) > udev->bus_mA) {
			insufficient_power++;
			continue;
		}

		/*
		 * Select first configuration as default for audio so that
		 * devices that don't comply with UAC3 protocol are supported.
		 * But, still iterate through other configurations and
		 * select UAC3 compliant config if present.
		 */
		if (desc && is_audio(desc)) {
			/* Always prefer the first found UAC3 config */
			if (is_uac3_config(desc)) {
				best = c;
				break;
			}

			/* If there is no UAC3 config, prefer the first config */
			else if (i == 0)
				best = c;

			/* Unconditional continue, because the rest of the code
			 * in the loop is irrelevant for audio devices, and
			 * because it can reassign best, which for audio devices
			 * we don't want.
			 */
			continue;
		}

		/* When the first config's first interface is one of Microsoft's
		 * pet nonstandard Ethernet-over-USB protocols, ignore it unless
		 * this kernel has enabled the necessary host side driver.
		 * But: Don't ignore it if it's the only config.
		 */
		if (i == 0 && num_configs > 1 && desc &&
				(is_rndis(desc) || is_activesync(desc))) {
#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
			continue;
#else
			best = c;
#endif
		}

		/* From the remaining configs, choose the first one whose
		 * first interface is for a non-vendor-specific class.
		 * Reason: Linux is more likely to have a class driver
		 * than a vendor-specific driver. */
		else if (udev->descriptor.bDeviceClass !=
						USB_CLASS_VENDOR_SPEC &&
				(desc && desc->bInterfaceClass !=
						USB_CLASS_VENDOR_SPEC)) {
			best = c;
			break;
		}

		/* If all the remaining configs are vendor-specific,
		 * choose the first one. */
		else if (!best)
			best = c;
	}

	if (insufficient_power > 0)
		dev_info(&udev->dev, "rejected %d configuration%s "
			"due to insufficient available bus power\n",
			insufficient_power, plural(insufficient_power));

	if (best) {
		i = best->desc.bConfigurationValue;
		dev_dbg(&udev->dev,
			"configuration #%d chosen from %d choice%s\n",
			i, num_configs, plural(num_configs));
	} else {
		i = -1;
		dev_warn(&udev->dev,
			"no configuration chosen from %d choice%s\n",
			num_configs, plural(num_configs));
	}
	return i;
}
EXPORT_SYMBOL_GPL(usb_choose_configuration);

static int __check_for_non_generic_match(struct device_driver *drv, void *data)
{
	struct usb_device *udev = data;
	struct usb_device_driver *udrv;

	if (!is_usb_device_driver(drv))
		return 0;
	udrv = to_usb_device_driver(drv);
	if (udrv == &usb_generic_driver)
		return 0;
	if (usb_device_match_id(udev, udrv->id_table) != NULL)
		return 1;
	return (udrv->match && udrv->match(udev));
}

static bool usb_generic_driver_match(struct usb_device *udev)
{
	if (udev->use_generic_driver)
		return true;

	/*
	 * If any other driver wants the device, leave the device to this other
	 * driver.
	 */
	if (bus_for_each_drv(&usb_bus_type, NULL, udev, __check_for_non_generic_match))
		return false;

	return true;
}

int usb_generic_driver_probe(struct usb_device *udev)
{
	int err, c;

	/* Choose and set the configuration.  This registers the interfaces
	 * with the driver core and lets interface drivers bind to them.
	 */
	if (udev->authorized == 0)
		dev_err(&udev->dev, "Device is not authorized for usage\n");
	else {
		c = usb_choose_configuration(udev);
		if (c >= 0) {
			err = usb_set_configuration(udev, c);
			if (err && err != -ENODEV) {
				dev_err(&udev->dev, "can't set config #%d, error %d\n",
					c, err);
				/* This need not be fatal.  The user can try to
				 * set other configurations. */
			}
		}
	}
	/* USB device state == configured ... usable */
	usb_notify_add_device(udev);

	return 0;
}

void usb_generic_driver_disconnect(struct usb_device *udev)
{
	usb_notify_remove_device(udev);

	/* if this is only an unbind, not a physical disconnect, then
	 * unconfigure the device */
	if (udev->actconfig)
		usb_set_configuration(udev, -1);
}

#ifdef	CONFIG_PM

int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg)
{
	int rc;

	/* Normal USB devices suspend through their upstream port.
	 * Root hubs don't have upstream ports to suspend,
	 * so we have to shut down their downstream HC-to-USB
	 * interfaces manually by doing a bus (or "global") suspend.
	 */
	if (!udev->parent)
		rc = hcd_bus_suspend(udev, msg);

	/*
	 * Non-root USB2 devices don't need to do anything for FREEZE
	 * or PRETHAW. USB3 devices don't support global suspend and
	 * needs to be selectively suspended.
	 */
	else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
		 && (udev->speed < USB_SPEED_SUPER))
		rc = 0;
	else
		rc = usb_port_suspend(udev, msg);

	if (rc == 0)
		usbfs_notify_suspend(udev);
	return rc;
}

int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg)
{
	int rc;

	/* Normal USB devices resume/reset through their upstream port.
	 * Root hubs don't have upstream ports to resume or reset,
	 * so we have to start up their downstream HC-to-USB
	 * interfaces manually by doing a bus (or "global") resume.
	 */
	if (!udev->parent)
		rc = hcd_bus_resume(udev, msg);
	else
		rc = usb_port_resume(udev, msg);

	if (rc == 0)
		usbfs_notify_resume(udev);
	return rc;
}

#endif	/* CONFIG_PM */

struct usb_device_driver usb_generic_driver = {
	.name =	"usb",
	.match = usb_generic_driver_match,
	.probe = usb_generic_driver_probe,
	.disconnect = usb_generic_driver_disconnect,
#ifdef	CONFIG_PM
	.suspend = usb_generic_driver_suspend,
	.resume = usb_generic_driver_resume,
#endif
	.supports_autosuspend = 1,
};