xref: /linux/drivers/usb/core/hcd.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  * (C) Copyright Linus Torvalds 1999
3  * (C) Copyright Johannes Erdfelt 1999-2001
4  * (C) Copyright Andreas Gal 1999
5  * (C) Copyright Gregory P. Smith 1999
6  * (C) Copyright Deti Fliegl 1999
7  * (C) Copyright Randy Dunlap 2000
8  * (C) Copyright David Brownell 2000-2002
9  *
10  * This program is free software; you can redistribute it and/or modify it
11  * under the terms of the GNU General Public License as published by the
12  * Free Software Foundation; either version 2 of the License, or (at your
13  * option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18  * for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software Foundation,
22  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23  */
24 
25 #include <linux/module.h>
26 #include <linux/version.h>
27 #include <linux/kernel.h>
28 #include <linux/slab.h>
29 #include <linux/completion.h>
30 #include <linux/utsname.h>
31 #include <linux/mm.h>
32 #include <asm/io.h>
33 #include <linux/device.h>
34 #include <linux/dma-mapping.h>
35 #include <linux/mutex.h>
36 #include <asm/irq.h>
37 #include <asm/byteorder.h>
38 #include <asm/unaligned.h>
39 #include <linux/platform_device.h>
40 #include <linux/workqueue.h>
41 #include <linux/pm_runtime.h>
42 
43 #include <linux/usb.h>
44 #include <linux/usb/hcd.h>
45 
46 #include "usb.h"
47 
48 
49 /*-------------------------------------------------------------------------*/
50 
51 /*
52  * USB Host Controller Driver framework
53  *
54  * Plugs into usbcore (usb_bus) and lets HCDs share code, minimizing
55  * HCD-specific behaviors/bugs.
56  *
57  * This does error checks, tracks devices and urbs, and delegates to a
58  * "hc_driver" only for code (and data) that really needs to know about
59  * hardware differences.  That includes root hub registers, i/o queues,
60  * and so on ... but as little else as possible.
61  *
62  * Shared code includes most of the "root hub" code (these are emulated,
63  * though each HC's hardware works differently) and PCI glue, plus request
64  * tracking overhead.  The HCD code should only block on spinlocks or on
65  * hardware handshaking; blocking on software events (such as other kernel
66  * threads releasing resources, or completing actions) is all generic.
67  *
68  * Happens the USB 2.0 spec says this would be invisible inside the "USBD",
69  * and includes mostly a "HCDI" (HCD Interface) along with some APIs used
70  * only by the hub driver ... and that neither should be seen or used by
71  * usb client device drivers.
72  *
73  * Contributors of ideas or unattributed patches include: David Brownell,
74  * Roman Weissgaerber, Rory Bolt, Greg Kroah-Hartman, ...
75  *
76  * HISTORY:
77  * 2002-02-21	Pull in most of the usb_bus support from usb.c; some
78  *		associated cleanup.  "usb_hcd" still != "usb_bus".
79  * 2001-12-12	Initial patch version for Linux 2.5.1 kernel.
80  */
81 
82 /*-------------------------------------------------------------------------*/
83 
84 /* Keep track of which host controller drivers are loaded */
85 unsigned long usb_hcds_loaded;
86 EXPORT_SYMBOL_GPL(usb_hcds_loaded);
87 
88 /* host controllers we manage */
89 LIST_HEAD (usb_bus_list);
90 EXPORT_SYMBOL_GPL (usb_bus_list);
91 
92 /* used when allocating bus numbers */
93 #define USB_MAXBUS		64
94 struct usb_busmap {
95 	unsigned long busmap [USB_MAXBUS / (8*sizeof (unsigned long))];
96 };
97 static struct usb_busmap busmap;
98 
99 /* used when updating list of hcds */
100 DEFINE_MUTEX(usb_bus_list_lock);	/* exported only for usbfs */
101 EXPORT_SYMBOL_GPL (usb_bus_list_lock);
102 
103 /* used for controlling access to virtual root hubs */
104 static DEFINE_SPINLOCK(hcd_root_hub_lock);
105 
106 /* used when updating an endpoint's URB list */
107 static DEFINE_SPINLOCK(hcd_urb_list_lock);
108 
109 /* used to protect against unlinking URBs after the device is gone */
110 static DEFINE_SPINLOCK(hcd_urb_unlink_lock);
111 
112 /* wait queue for synchronous unlinks */
113 DECLARE_WAIT_QUEUE_HEAD(usb_kill_urb_queue);
114 
115 static inline int is_root_hub(struct usb_device *udev)
116 {
117 	return (udev->parent == NULL);
118 }
119 
120 /*-------------------------------------------------------------------------*/
121 
122 /*
123  * Sharable chunks of root hub code.
124  */
125 
126 /*-------------------------------------------------------------------------*/
127 
128 #define KERNEL_REL	((LINUX_VERSION_CODE >> 16) & 0x0ff)
129 #define KERNEL_VER	((LINUX_VERSION_CODE >> 8) & 0x0ff)
130 
131 /* usb 3.0 root hub device descriptor */
132 static const u8 usb3_rh_dev_descriptor[18] = {
133 	0x12,       /*  __u8  bLength; */
134 	0x01,       /*  __u8  bDescriptorType; Device */
135 	0x00, 0x03, /*  __le16 bcdUSB; v3.0 */
136 
137 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
138 	0x00,	    /*  __u8  bDeviceSubClass; */
139 	0x03,       /*  __u8  bDeviceProtocol; USB 3.0 hub */
140 	0x09,       /*  __u8  bMaxPacketSize0; 2^9 = 512 Bytes */
141 
142 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
143 	0x03, 0x00, /*  __le16 idProduct; device 0x0003 */
144 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
145 
146 	0x03,       /*  __u8  iManufacturer; */
147 	0x02,       /*  __u8  iProduct; */
148 	0x01,       /*  __u8  iSerialNumber; */
149 	0x01        /*  __u8  bNumConfigurations; */
150 };
151 
152 /* usb 2.0 root hub device descriptor */
153 static const u8 usb2_rh_dev_descriptor [18] = {
154 	0x12,       /*  __u8  bLength; */
155 	0x01,       /*  __u8  bDescriptorType; Device */
156 	0x00, 0x02, /*  __le16 bcdUSB; v2.0 */
157 
158 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
159 	0x00,	    /*  __u8  bDeviceSubClass; */
160 	0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
161 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
162 
163 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
164 	0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
165 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
166 
167 	0x03,       /*  __u8  iManufacturer; */
168 	0x02,       /*  __u8  iProduct; */
169 	0x01,       /*  __u8  iSerialNumber; */
170 	0x01        /*  __u8  bNumConfigurations; */
171 };
172 
173 /* no usb 2.0 root hub "device qualifier" descriptor: one speed only */
174 
175 /* usb 1.1 root hub device descriptor */
176 static const u8 usb11_rh_dev_descriptor [18] = {
177 	0x12,       /*  __u8  bLength; */
178 	0x01,       /*  __u8  bDescriptorType; Device */
179 	0x10, 0x01, /*  __le16 bcdUSB; v1.1 */
180 
181 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
182 	0x00,	    /*  __u8  bDeviceSubClass; */
183 	0x00,       /*  __u8  bDeviceProtocol; [ low/full speeds only ] */
184 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
185 
186 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
187 	0x01, 0x00, /*  __le16 idProduct; device 0x0001 */
188 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
189 
190 	0x03,       /*  __u8  iManufacturer; */
191 	0x02,       /*  __u8  iProduct; */
192 	0x01,       /*  __u8  iSerialNumber; */
193 	0x01        /*  __u8  bNumConfigurations; */
194 };
195 
196 
197 /*-------------------------------------------------------------------------*/
198 
199 /* Configuration descriptors for our root hubs */
200 
201 static const u8 fs_rh_config_descriptor [] = {
202 
203 	/* one configuration */
204 	0x09,       /*  __u8  bLength; */
205 	0x02,       /*  __u8  bDescriptorType; Configuration */
206 	0x19, 0x00, /*  __le16 wTotalLength; */
207 	0x01,       /*  __u8  bNumInterfaces; (1) */
208 	0x01,       /*  __u8  bConfigurationValue; */
209 	0x00,       /*  __u8  iConfiguration; */
210 	0xc0,       /*  __u8  bmAttributes;
211 				 Bit 7: must be set,
212 				     6: Self-powered,
213 				     5: Remote wakeup,
214 				     4..0: resvd */
215 	0x00,       /*  __u8  MaxPower; */
216 
217 	/* USB 1.1:
218 	 * USB 2.0, single TT organization (mandatory):
219 	 *	one interface, protocol 0
220 	 *
221 	 * USB 2.0, multiple TT organization (optional):
222 	 *	two interfaces, protocols 1 (like single TT)
223 	 *	and 2 (multiple TT mode) ... config is
224 	 *	sometimes settable
225 	 *	NOT IMPLEMENTED
226 	 */
227 
228 	/* one interface */
229 	0x09,       /*  __u8  if_bLength; */
230 	0x04,       /*  __u8  if_bDescriptorType; Interface */
231 	0x00,       /*  __u8  if_bInterfaceNumber; */
232 	0x00,       /*  __u8  if_bAlternateSetting; */
233 	0x01,       /*  __u8  if_bNumEndpoints; */
234 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
235 	0x00,       /*  __u8  if_bInterfaceSubClass; */
236 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
237 	0x00,       /*  __u8  if_iInterface; */
238 
239 	/* one endpoint (status change endpoint) */
240 	0x07,       /*  __u8  ep_bLength; */
241 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
242 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
243  	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
244  	0x02, 0x00, /*  __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) */
245 	0xff        /*  __u8  ep_bInterval; (255ms -- usb 2.0 spec) */
246 };
247 
248 static const u8 hs_rh_config_descriptor [] = {
249 
250 	/* one configuration */
251 	0x09,       /*  __u8  bLength; */
252 	0x02,       /*  __u8  bDescriptorType; Configuration */
253 	0x19, 0x00, /*  __le16 wTotalLength; */
254 	0x01,       /*  __u8  bNumInterfaces; (1) */
255 	0x01,       /*  __u8  bConfigurationValue; */
256 	0x00,       /*  __u8  iConfiguration; */
257 	0xc0,       /*  __u8  bmAttributes;
258 				 Bit 7: must be set,
259 				     6: Self-powered,
260 				     5: Remote wakeup,
261 				     4..0: resvd */
262 	0x00,       /*  __u8  MaxPower; */
263 
264 	/* USB 1.1:
265 	 * USB 2.0, single TT organization (mandatory):
266 	 *	one interface, protocol 0
267 	 *
268 	 * USB 2.0, multiple TT organization (optional):
269 	 *	two interfaces, protocols 1 (like single TT)
270 	 *	and 2 (multiple TT mode) ... config is
271 	 *	sometimes settable
272 	 *	NOT IMPLEMENTED
273 	 */
274 
275 	/* one interface */
276 	0x09,       /*  __u8  if_bLength; */
277 	0x04,       /*  __u8  if_bDescriptorType; Interface */
278 	0x00,       /*  __u8  if_bInterfaceNumber; */
279 	0x00,       /*  __u8  if_bAlternateSetting; */
280 	0x01,       /*  __u8  if_bNumEndpoints; */
281 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
282 	0x00,       /*  __u8  if_bInterfaceSubClass; */
283 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
284 	0x00,       /*  __u8  if_iInterface; */
285 
286 	/* one endpoint (status change endpoint) */
287 	0x07,       /*  __u8  ep_bLength; */
288 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
289 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
290  	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
291 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
292 		     * see hub.c:hub_configure() for details. */
293 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
294 	0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
295 };
296 
297 static const u8 ss_rh_config_descriptor[] = {
298 	/* one configuration */
299 	0x09,       /*  __u8  bLength; */
300 	0x02,       /*  __u8  bDescriptorType; Configuration */
301 	0x19, 0x00, /*  __le16 wTotalLength; FIXME */
302 	0x01,       /*  __u8  bNumInterfaces; (1) */
303 	0x01,       /*  __u8  bConfigurationValue; */
304 	0x00,       /*  __u8  iConfiguration; */
305 	0xc0,       /*  __u8  bmAttributes;
306 				 Bit 7: must be set,
307 				     6: Self-powered,
308 				     5: Remote wakeup,
309 				     4..0: resvd */
310 	0x00,       /*  __u8  MaxPower; */
311 
312 	/* one interface */
313 	0x09,       /*  __u8  if_bLength; */
314 	0x04,       /*  __u8  if_bDescriptorType; Interface */
315 	0x00,       /*  __u8  if_bInterfaceNumber; */
316 	0x00,       /*  __u8  if_bAlternateSetting; */
317 	0x01,       /*  __u8  if_bNumEndpoints; */
318 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
319 	0x00,       /*  __u8  if_bInterfaceSubClass; */
320 	0x00,       /*  __u8  if_bInterfaceProtocol; */
321 	0x00,       /*  __u8  if_iInterface; */
322 
323 	/* one endpoint (status change endpoint) */
324 	0x07,       /*  __u8  ep_bLength; */
325 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
326 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
327 	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
328 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
329 		     * see hub.c:hub_configure() for details. */
330 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
331 	0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
332 	/*
333 	 * All 3.0 hubs should have an endpoint companion descriptor,
334 	 * but we're ignoring that for now.  FIXME?
335 	 */
336 };
337 
338 /*-------------------------------------------------------------------------*/
339 
340 /**
341  * ascii2desc() - Helper routine for producing UTF-16LE string descriptors
342  * @s: Null-terminated ASCII (actually ISO-8859-1) string
343  * @buf: Buffer for USB string descriptor (header + UTF-16LE)
344  * @len: Length (in bytes; may be odd) of descriptor buffer.
345  *
346  * The return value is the number of bytes filled in: 2 + 2*strlen(s) or
347  * buflen, whichever is less.
348  *
349  * USB String descriptors can contain at most 126 characters; input
350  * strings longer than that are truncated.
351  */
352 static unsigned
353 ascii2desc(char const *s, u8 *buf, unsigned len)
354 {
355 	unsigned n, t = 2 + 2*strlen(s);
356 
357 	if (t > 254)
358 		t = 254;	/* Longest possible UTF string descriptor */
359 	if (len > t)
360 		len = t;
361 
362 	t += USB_DT_STRING << 8;	/* Now t is first 16 bits to store */
363 
364 	n = len;
365 	while (n--) {
366 		*buf++ = t;
367 		if (!n--)
368 			break;
369 		*buf++ = t >> 8;
370 		t = (unsigned char)*s++;
371 	}
372 	return len;
373 }
374 
375 /**
376  * rh_string() - provides string descriptors for root hub
377  * @id: the string ID number (0: langids, 1: serial #, 2: product, 3: vendor)
378  * @hcd: the host controller for this root hub
379  * @data: buffer for output packet
380  * @len: length of the provided buffer
381  *
382  * Produces either a manufacturer, product or serial number string for the
383  * virtual root hub device.
384  * Returns the number of bytes filled in: the length of the descriptor or
385  * of the provided buffer, whichever is less.
386  */
387 static unsigned
388 rh_string(int id, struct usb_hcd const *hcd, u8 *data, unsigned len)
389 {
390 	char buf[100];
391 	char const *s;
392 	static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04};
393 
394 	// language ids
395 	switch (id) {
396 	case 0:
397 		/* Array of LANGID codes (0x0409 is MSFT-speak for "en-us") */
398 		/* See http://www.usb.org/developers/docs/USB_LANGIDs.pdf */
399 		if (len > 4)
400 			len = 4;
401 		memcpy(data, langids, len);
402 		return len;
403 	case 1:
404 		/* Serial number */
405 		s = hcd->self.bus_name;
406 		break;
407 	case 2:
408 		/* Product name */
409 		s = hcd->product_desc;
410 		break;
411 	case 3:
412 		/* Manufacturer */
413 		snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
414 			init_utsname()->release, hcd->driver->description);
415 		s = buf;
416 		break;
417 	default:
418 		/* Can't happen; caller guarantees it */
419 		return 0;
420 	}
421 
422 	return ascii2desc(s, data, len);
423 }
424 
425 
426 /* Root hub control transfers execute synchronously */
427 static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
428 {
429 	struct usb_ctrlrequest *cmd;
430  	u16		typeReq, wValue, wIndex, wLength;
431 	u8		*ubuf = urb->transfer_buffer;
432 	u8		tbuf [sizeof (struct usb_hub_descriptor)]
433 		__attribute__((aligned(4)));
434 	const u8	*bufp = tbuf;
435 	unsigned	len = 0;
436 	int		status;
437 	u8		patch_wakeup = 0;
438 	u8		patch_protocol = 0;
439 
440 	might_sleep();
441 
442 	spin_lock_irq(&hcd_root_hub_lock);
443 	status = usb_hcd_link_urb_to_ep(hcd, urb);
444 	spin_unlock_irq(&hcd_root_hub_lock);
445 	if (status)
446 		return status;
447 	urb->hcpriv = hcd;	/* Indicate it's queued */
448 
449 	cmd = (struct usb_ctrlrequest *) urb->setup_packet;
450 	typeReq  = (cmd->bRequestType << 8) | cmd->bRequest;
451 	wValue   = le16_to_cpu (cmd->wValue);
452 	wIndex   = le16_to_cpu (cmd->wIndex);
453 	wLength  = le16_to_cpu (cmd->wLength);
454 
455 	if (wLength > urb->transfer_buffer_length)
456 		goto error;
457 
458 	urb->actual_length = 0;
459 	switch (typeReq) {
460 
461 	/* DEVICE REQUESTS */
462 
463 	/* The root hub's remote wakeup enable bit is implemented using
464 	 * driver model wakeup flags.  If this system supports wakeup
465 	 * through USB, userspace may change the default "allow wakeup"
466 	 * policy through sysfs or these calls.
467 	 *
468 	 * Most root hubs support wakeup from downstream devices, for
469 	 * runtime power management (disabling USB clocks and reducing
470 	 * VBUS power usage).  However, not all of them do so; silicon,
471 	 * board, and BIOS bugs here are not uncommon, so these can't
472 	 * be treated quite like external hubs.
473 	 *
474 	 * Likewise, not all root hubs will pass wakeup events upstream,
475 	 * to wake up the whole system.  So don't assume root hub and
476 	 * controller capabilities are identical.
477 	 */
478 
479 	case DeviceRequest | USB_REQ_GET_STATUS:
480 		tbuf [0] = (device_may_wakeup(&hcd->self.root_hub->dev)
481 					<< USB_DEVICE_REMOTE_WAKEUP)
482 				| (1 << USB_DEVICE_SELF_POWERED);
483 		tbuf [1] = 0;
484 		len = 2;
485 		break;
486 	case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
487 		if (wValue == USB_DEVICE_REMOTE_WAKEUP)
488 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 0);
489 		else
490 			goto error;
491 		break;
492 	case DeviceOutRequest | USB_REQ_SET_FEATURE:
493 		if (device_can_wakeup(&hcd->self.root_hub->dev)
494 				&& wValue == USB_DEVICE_REMOTE_WAKEUP)
495 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 1);
496 		else
497 			goto error;
498 		break;
499 	case DeviceRequest | USB_REQ_GET_CONFIGURATION:
500 		tbuf [0] = 1;
501 		len = 1;
502 			/* FALLTHROUGH */
503 	case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
504 		break;
505 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
506 		switch (wValue & 0xff00) {
507 		case USB_DT_DEVICE << 8:
508 			switch (hcd->driver->flags & HCD_MASK) {
509 			case HCD_USB3:
510 				bufp = usb3_rh_dev_descriptor;
511 				break;
512 			case HCD_USB2:
513 				bufp = usb2_rh_dev_descriptor;
514 				break;
515 			case HCD_USB11:
516 				bufp = usb11_rh_dev_descriptor;
517 				break;
518 			default:
519 				goto error;
520 			}
521 			len = 18;
522 			if (hcd->has_tt)
523 				patch_protocol = 1;
524 			break;
525 		case USB_DT_CONFIG << 8:
526 			switch (hcd->driver->flags & HCD_MASK) {
527 			case HCD_USB3:
528 				bufp = ss_rh_config_descriptor;
529 				len = sizeof ss_rh_config_descriptor;
530 				break;
531 			case HCD_USB2:
532 				bufp = hs_rh_config_descriptor;
533 				len = sizeof hs_rh_config_descriptor;
534 				break;
535 			case HCD_USB11:
536 				bufp = fs_rh_config_descriptor;
537 				len = sizeof fs_rh_config_descriptor;
538 				break;
539 			default:
540 				goto error;
541 			}
542 			if (device_can_wakeup(&hcd->self.root_hub->dev))
543 				patch_wakeup = 1;
544 			break;
545 		case USB_DT_STRING << 8:
546 			if ((wValue & 0xff) < 4)
547 				urb->actual_length = rh_string(wValue & 0xff,
548 						hcd, ubuf, wLength);
549 			else /* unsupported IDs --> "protocol stall" */
550 				goto error;
551 			break;
552 		default:
553 			goto error;
554 		}
555 		break;
556 	case DeviceRequest | USB_REQ_GET_INTERFACE:
557 		tbuf [0] = 0;
558 		len = 1;
559 			/* FALLTHROUGH */
560 	case DeviceOutRequest | USB_REQ_SET_INTERFACE:
561 		break;
562 	case DeviceOutRequest | USB_REQ_SET_ADDRESS:
563 		// wValue == urb->dev->devaddr
564 		dev_dbg (hcd->self.controller, "root hub device address %d\n",
565 			wValue);
566 		break;
567 
568 	/* INTERFACE REQUESTS (no defined feature/status flags) */
569 
570 	/* ENDPOINT REQUESTS */
571 
572 	case EndpointRequest | USB_REQ_GET_STATUS:
573 		// ENDPOINT_HALT flag
574 		tbuf [0] = 0;
575 		tbuf [1] = 0;
576 		len = 2;
577 			/* FALLTHROUGH */
578 	case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
579 	case EndpointOutRequest | USB_REQ_SET_FEATURE:
580 		dev_dbg (hcd->self.controller, "no endpoint features yet\n");
581 		break;
582 
583 	/* CLASS REQUESTS (and errors) */
584 
585 	default:
586 		/* non-generic request */
587 		switch (typeReq) {
588 		case GetHubStatus:
589 		case GetPortStatus:
590 			len = 4;
591 			break;
592 		case GetHubDescriptor:
593 			len = sizeof (struct usb_hub_descriptor);
594 			break;
595 		}
596 		status = hcd->driver->hub_control (hcd,
597 			typeReq, wValue, wIndex,
598 			tbuf, wLength);
599 		break;
600 error:
601 		/* "protocol stall" on error */
602 		status = -EPIPE;
603 	}
604 
605 	if (status) {
606 		len = 0;
607 		if (status != -EPIPE) {
608 			dev_dbg (hcd->self.controller,
609 				"CTRL: TypeReq=0x%x val=0x%x "
610 				"idx=0x%x len=%d ==> %d\n",
611 				typeReq, wValue, wIndex,
612 				wLength, status);
613 		}
614 	}
615 	if (len) {
616 		if (urb->transfer_buffer_length < len)
617 			len = urb->transfer_buffer_length;
618 		urb->actual_length = len;
619 		// always USB_DIR_IN, toward host
620 		memcpy (ubuf, bufp, len);
621 
622 		/* report whether RH hardware supports remote wakeup */
623 		if (patch_wakeup &&
624 				len > offsetof (struct usb_config_descriptor,
625 						bmAttributes))
626 			((struct usb_config_descriptor *)ubuf)->bmAttributes
627 				|= USB_CONFIG_ATT_WAKEUP;
628 
629 		/* report whether RH hardware has an integrated TT */
630 		if (patch_protocol &&
631 				len > offsetof(struct usb_device_descriptor,
632 						bDeviceProtocol))
633 			((struct usb_device_descriptor *) ubuf)->
634 					bDeviceProtocol = 1;
635 	}
636 
637 	/* any errors get returned through the urb completion */
638 	spin_lock_irq(&hcd_root_hub_lock);
639 	usb_hcd_unlink_urb_from_ep(hcd, urb);
640 
641 	/* This peculiar use of spinlocks echoes what real HC drivers do.
642 	 * Avoiding calls to local_irq_disable/enable makes the code
643 	 * RT-friendly.
644 	 */
645 	spin_unlock(&hcd_root_hub_lock);
646 	usb_hcd_giveback_urb(hcd, urb, status);
647 	spin_lock(&hcd_root_hub_lock);
648 
649 	spin_unlock_irq(&hcd_root_hub_lock);
650 	return 0;
651 }
652 
653 /*-------------------------------------------------------------------------*/
654 
655 /*
656  * Root Hub interrupt transfers are polled using a timer if the
657  * driver requests it; otherwise the driver is responsible for
658  * calling usb_hcd_poll_rh_status() when an event occurs.
659  *
660  * Completions are called in_interrupt(), but they may or may not
661  * be in_irq().
662  */
663 void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
664 {
665 	struct urb	*urb;
666 	int		length;
667 	unsigned long	flags;
668 	char		buffer[6];	/* Any root hubs with > 31 ports? */
669 
670 	if (unlikely(!hcd->rh_pollable))
671 		return;
672 	if (!hcd->uses_new_polling && !hcd->status_urb)
673 		return;
674 
675 	length = hcd->driver->hub_status_data(hcd, buffer);
676 	if (length > 0) {
677 
678 		/* try to complete the status urb */
679 		spin_lock_irqsave(&hcd_root_hub_lock, flags);
680 		urb = hcd->status_urb;
681 		if (urb) {
682 			clear_bit(HCD_FLAG_POLL_PENDING, &hcd->flags);
683 			hcd->status_urb = NULL;
684 			urb->actual_length = length;
685 			memcpy(urb->transfer_buffer, buffer, length);
686 
687 			usb_hcd_unlink_urb_from_ep(hcd, urb);
688 			spin_unlock(&hcd_root_hub_lock);
689 			usb_hcd_giveback_urb(hcd, urb, 0);
690 			spin_lock(&hcd_root_hub_lock);
691 		} else {
692 			length = 0;
693 			set_bit(HCD_FLAG_POLL_PENDING, &hcd->flags);
694 		}
695 		spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
696 	}
697 
698 	/* The USB 2.0 spec says 256 ms.  This is close enough and won't
699 	 * exceed that limit if HZ is 100. The math is more clunky than
700 	 * maybe expected, this is to make sure that all timers for USB devices
701 	 * fire at the same time to give the CPU a break inbetween */
702 	if (hcd->uses_new_polling ? HCD_POLL_RH(hcd) :
703 			(length == 0 && hcd->status_urb != NULL))
704 		mod_timer (&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
705 }
706 EXPORT_SYMBOL_GPL(usb_hcd_poll_rh_status);
707 
708 /* timer callback */
709 static void rh_timer_func (unsigned long _hcd)
710 {
711 	usb_hcd_poll_rh_status((struct usb_hcd *) _hcd);
712 }
713 
714 /*-------------------------------------------------------------------------*/
715 
716 static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
717 {
718 	int		retval;
719 	unsigned long	flags;
720 	unsigned	len = 1 + (urb->dev->maxchild / 8);
721 
722 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
723 	if (hcd->status_urb || urb->transfer_buffer_length < len) {
724 		dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
725 		retval = -EINVAL;
726 		goto done;
727 	}
728 
729 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
730 	if (retval)
731 		goto done;
732 
733 	hcd->status_urb = urb;
734 	urb->hcpriv = hcd;	/* indicate it's queued */
735 	if (!hcd->uses_new_polling)
736 		mod_timer(&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
737 
738 	/* If a status change has already occurred, report it ASAP */
739 	else if (HCD_POLL_PENDING(hcd))
740 		mod_timer(&hcd->rh_timer, jiffies);
741 	retval = 0;
742  done:
743 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
744 	return retval;
745 }
746 
747 static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
748 {
749 	if (usb_endpoint_xfer_int(&urb->ep->desc))
750 		return rh_queue_status (hcd, urb);
751 	if (usb_endpoint_xfer_control(&urb->ep->desc))
752 		return rh_call_control (hcd, urb);
753 	return -EINVAL;
754 }
755 
756 /*-------------------------------------------------------------------------*/
757 
758 /* Unlinks of root-hub control URBs are legal, but they don't do anything
759  * since these URBs always execute synchronously.
760  */
761 static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
762 {
763 	unsigned long	flags;
764 	int		rc;
765 
766 	spin_lock_irqsave(&hcd_root_hub_lock, flags);
767 	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
768 	if (rc)
769 		goto done;
770 
771 	if (usb_endpoint_num(&urb->ep->desc) == 0) {	/* Control URB */
772 		;	/* Do nothing */
773 
774 	} else {				/* Status URB */
775 		if (!hcd->uses_new_polling)
776 			del_timer (&hcd->rh_timer);
777 		if (urb == hcd->status_urb) {
778 			hcd->status_urb = NULL;
779 			usb_hcd_unlink_urb_from_ep(hcd, urb);
780 
781 			spin_unlock(&hcd_root_hub_lock);
782 			usb_hcd_giveback_urb(hcd, urb, status);
783 			spin_lock(&hcd_root_hub_lock);
784 		}
785 	}
786  done:
787 	spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
788 	return rc;
789 }
790 
791 
792 
793 /*
794  * Show & store the current value of authorized_default
795  */
796 static ssize_t usb_host_authorized_default_show(struct device *dev,
797 						struct device_attribute *attr,
798 						char *buf)
799 {
800 	struct usb_device *rh_usb_dev = to_usb_device(dev);
801 	struct usb_bus *usb_bus = rh_usb_dev->bus;
802 	struct usb_hcd *usb_hcd;
803 
804 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
805 		return -ENODEV;
806 	usb_hcd = bus_to_hcd(usb_bus);
807 	return snprintf(buf, PAGE_SIZE, "%u\n", usb_hcd->authorized_default);
808 }
809 
810 static ssize_t usb_host_authorized_default_store(struct device *dev,
811 						 struct device_attribute *attr,
812 						 const char *buf, size_t size)
813 {
814 	ssize_t result;
815 	unsigned val;
816 	struct usb_device *rh_usb_dev = to_usb_device(dev);
817 	struct usb_bus *usb_bus = rh_usb_dev->bus;
818 	struct usb_hcd *usb_hcd;
819 
820 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
821 		return -ENODEV;
822 	usb_hcd = bus_to_hcd(usb_bus);
823 	result = sscanf(buf, "%u\n", &val);
824 	if (result == 1) {
825 		usb_hcd->authorized_default = val? 1 : 0;
826 		result = size;
827 	}
828 	else
829 		result = -EINVAL;
830 	return result;
831 }
832 
833 static DEVICE_ATTR(authorized_default, 0644,
834 	    usb_host_authorized_default_show,
835 	    usb_host_authorized_default_store);
836 
837 
838 /* Group all the USB bus attributes */
839 static struct attribute *usb_bus_attrs[] = {
840 		&dev_attr_authorized_default.attr,
841 		NULL,
842 };
843 
844 static struct attribute_group usb_bus_attr_group = {
845 	.name = NULL,	/* we want them in the same directory */
846 	.attrs = usb_bus_attrs,
847 };
848 
849 
850 
851 /*-------------------------------------------------------------------------*/
852 
853 /**
854  * usb_bus_init - shared initialization code
855  * @bus: the bus structure being initialized
856  *
857  * This code is used to initialize a usb_bus structure, memory for which is
858  * separately managed.
859  */
860 static void usb_bus_init (struct usb_bus *bus)
861 {
862 	memset (&bus->devmap, 0, sizeof(struct usb_devmap));
863 
864 	bus->devnum_next = 1;
865 
866 	bus->root_hub = NULL;
867 	bus->busnum = -1;
868 	bus->bandwidth_allocated = 0;
869 	bus->bandwidth_int_reqs  = 0;
870 	bus->bandwidth_isoc_reqs = 0;
871 
872 	INIT_LIST_HEAD (&bus->bus_list);
873 }
874 
875 /*-------------------------------------------------------------------------*/
876 
877 /**
878  * usb_register_bus - registers the USB host controller with the usb core
879  * @bus: pointer to the bus to register
880  * Context: !in_interrupt()
881  *
882  * Assigns a bus number, and links the controller into usbcore data
883  * structures so that it can be seen by scanning the bus list.
884  */
885 static int usb_register_bus(struct usb_bus *bus)
886 {
887 	int result = -E2BIG;
888 	int busnum;
889 
890 	mutex_lock(&usb_bus_list_lock);
891 	busnum = find_next_zero_bit (busmap.busmap, USB_MAXBUS, 1);
892 	if (busnum >= USB_MAXBUS) {
893 		printk (KERN_ERR "%s: too many buses\n", usbcore_name);
894 		goto error_find_busnum;
895 	}
896 	set_bit (busnum, busmap.busmap);
897 	bus->busnum = busnum;
898 
899 	/* Add it to the local list of buses */
900 	list_add (&bus->bus_list, &usb_bus_list);
901 	mutex_unlock(&usb_bus_list_lock);
902 
903 	usb_notify_add_bus(bus);
904 
905 	dev_info (bus->controller, "new USB bus registered, assigned bus "
906 		  "number %d\n", bus->busnum);
907 	return 0;
908 
909 error_find_busnum:
910 	mutex_unlock(&usb_bus_list_lock);
911 	return result;
912 }
913 
914 /**
915  * usb_deregister_bus - deregisters the USB host controller
916  * @bus: pointer to the bus to deregister
917  * Context: !in_interrupt()
918  *
919  * Recycles the bus number, and unlinks the controller from usbcore data
920  * structures so that it won't be seen by scanning the bus list.
921  */
922 static void usb_deregister_bus (struct usb_bus *bus)
923 {
924 	dev_info (bus->controller, "USB bus %d deregistered\n", bus->busnum);
925 
926 	/*
927 	 * NOTE: make sure that all the devices are removed by the
928 	 * controller code, as well as having it call this when cleaning
929 	 * itself up
930 	 */
931 	mutex_lock(&usb_bus_list_lock);
932 	list_del (&bus->bus_list);
933 	mutex_unlock(&usb_bus_list_lock);
934 
935 	usb_notify_remove_bus(bus);
936 
937 	clear_bit (bus->busnum, busmap.busmap);
938 }
939 
940 /**
941  * register_root_hub - called by usb_add_hcd() to register a root hub
942  * @hcd: host controller for this root hub
943  *
944  * This function registers the root hub with the USB subsystem.  It sets up
945  * the device properly in the device tree and then calls usb_new_device()
946  * to register the usb device.  It also assigns the root hub's USB address
947  * (always 1).
948  */
949 static int register_root_hub(struct usb_hcd *hcd)
950 {
951 	struct device *parent_dev = hcd->self.controller;
952 	struct usb_device *usb_dev = hcd->self.root_hub;
953 	const int devnum = 1;
954 	int retval;
955 
956 	usb_dev->devnum = devnum;
957 	usb_dev->bus->devnum_next = devnum + 1;
958 	memset (&usb_dev->bus->devmap.devicemap, 0,
959 			sizeof usb_dev->bus->devmap.devicemap);
960 	set_bit (devnum, usb_dev->bus->devmap.devicemap);
961 	usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
962 
963 	mutex_lock(&usb_bus_list_lock);
964 
965 	usb_dev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
966 	retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE);
967 	if (retval != sizeof usb_dev->descriptor) {
968 		mutex_unlock(&usb_bus_list_lock);
969 		dev_dbg (parent_dev, "can't read %s device descriptor %d\n",
970 				dev_name(&usb_dev->dev), retval);
971 		return (retval < 0) ? retval : -EMSGSIZE;
972 	}
973 
974 	retval = usb_new_device (usb_dev);
975 	if (retval) {
976 		dev_err (parent_dev, "can't register root hub for %s, %d\n",
977 				dev_name(&usb_dev->dev), retval);
978 	}
979 	mutex_unlock(&usb_bus_list_lock);
980 
981 	if (retval == 0) {
982 		spin_lock_irq (&hcd_root_hub_lock);
983 		hcd->rh_registered = 1;
984 		spin_unlock_irq (&hcd_root_hub_lock);
985 
986 		/* Did the HC die before the root hub was registered? */
987 		if (hcd->state == HC_STATE_HALT)
988 			usb_hc_died (hcd);	/* This time clean up */
989 	}
990 
991 	return retval;
992 }
993 
994 
995 /*-------------------------------------------------------------------------*/
996 
997 /**
998  * usb_calc_bus_time - approximate periodic transaction time in nanoseconds
999  * @speed: from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
1000  * @is_input: true iff the transaction sends data to the host
1001  * @isoc: true for isochronous transactions, false for interrupt ones
1002  * @bytecount: how many bytes in the transaction.
1003  *
1004  * Returns approximate bus time in nanoseconds for a periodic transaction.
1005  * See USB 2.0 spec section 5.11.3; only periodic transfers need to be
1006  * scheduled in software, this function is only used for such scheduling.
1007  */
1008 long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount)
1009 {
1010 	unsigned long	tmp;
1011 
1012 	switch (speed) {
1013 	case USB_SPEED_LOW: 	/* INTR only */
1014 		if (is_input) {
1015 			tmp = (67667L * (31L + 10L * BitTime (bytecount))) / 1000L;
1016 			return (64060L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
1017 		} else {
1018 			tmp = (66700L * (31L + 10L * BitTime (bytecount))) / 1000L;
1019 			return (64107L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
1020 		}
1021 	case USB_SPEED_FULL:	/* ISOC or INTR */
1022 		if (isoc) {
1023 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1024 			return (((is_input) ? 7268L : 6265L) + BW_HOST_DELAY + tmp);
1025 		} else {
1026 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1027 			return (9107L + BW_HOST_DELAY + tmp);
1028 		}
1029 	case USB_SPEED_HIGH:	/* ISOC or INTR */
1030 		// FIXME adjust for input vs output
1031 		if (isoc)
1032 			tmp = HS_NSECS_ISO (bytecount);
1033 		else
1034 			tmp = HS_NSECS (bytecount);
1035 		return tmp;
1036 	default:
1037 		pr_debug ("%s: bogus device speed!\n", usbcore_name);
1038 		return -1;
1039 	}
1040 }
1041 EXPORT_SYMBOL_GPL(usb_calc_bus_time);
1042 
1043 
1044 /*-------------------------------------------------------------------------*/
1045 
1046 /*
1047  * Generic HC operations.
1048  */
1049 
1050 /*-------------------------------------------------------------------------*/
1051 
1052 /**
1053  * usb_hcd_link_urb_to_ep - add an URB to its endpoint queue
1054  * @hcd: host controller to which @urb was submitted
1055  * @urb: URB being submitted
1056  *
1057  * Host controller drivers should call this routine in their enqueue()
1058  * method.  The HCD's private spinlock must be held and interrupts must
1059  * be disabled.  The actions carried out here are required for URB
1060  * submission, as well as for endpoint shutdown and for usb_kill_urb.
1061  *
1062  * Returns 0 for no error, otherwise a negative error code (in which case
1063  * the enqueue() method must fail).  If no error occurs but enqueue() fails
1064  * anyway, it must call usb_hcd_unlink_urb_from_ep() before releasing
1065  * the private spinlock and returning.
1066  */
1067 int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
1068 {
1069 	int		rc = 0;
1070 
1071 	spin_lock(&hcd_urb_list_lock);
1072 
1073 	/* Check that the URB isn't being killed */
1074 	if (unlikely(atomic_read(&urb->reject))) {
1075 		rc = -EPERM;
1076 		goto done;
1077 	}
1078 
1079 	if (unlikely(!urb->ep->enabled)) {
1080 		rc = -ENOENT;
1081 		goto done;
1082 	}
1083 
1084 	if (unlikely(!urb->dev->can_submit)) {
1085 		rc = -EHOSTUNREACH;
1086 		goto done;
1087 	}
1088 
1089 	/*
1090 	 * Check the host controller's state and add the URB to the
1091 	 * endpoint's queue.
1092 	 */
1093 	switch (hcd->state) {
1094 	case HC_STATE_RUNNING:
1095 	case HC_STATE_RESUMING:
1096 		urb->unlinked = 0;
1097 		list_add_tail(&urb->urb_list, &urb->ep->urb_list);
1098 		break;
1099 	default:
1100 		rc = -ESHUTDOWN;
1101 		goto done;
1102 	}
1103  done:
1104 	spin_unlock(&hcd_urb_list_lock);
1105 	return rc;
1106 }
1107 EXPORT_SYMBOL_GPL(usb_hcd_link_urb_to_ep);
1108 
1109 /**
1110  * usb_hcd_check_unlink_urb - check whether an URB may be unlinked
1111  * @hcd: host controller to which @urb was submitted
1112  * @urb: URB being checked for unlinkability
1113  * @status: error code to store in @urb if the unlink succeeds
1114  *
1115  * Host controller drivers should call this routine in their dequeue()
1116  * method.  The HCD's private spinlock must be held and interrupts must
1117  * be disabled.  The actions carried out here are required for making
1118  * sure than an unlink is valid.
1119  *
1120  * Returns 0 for no error, otherwise a negative error code (in which case
1121  * the dequeue() method must fail).  The possible error codes are:
1122  *
1123  *	-EIDRM: @urb was not submitted or has already completed.
1124  *		The completion function may not have been called yet.
1125  *
1126  *	-EBUSY: @urb has already been unlinked.
1127  */
1128 int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,
1129 		int status)
1130 {
1131 	struct list_head	*tmp;
1132 
1133 	/* insist the urb is still queued */
1134 	list_for_each(tmp, &urb->ep->urb_list) {
1135 		if (tmp == &urb->urb_list)
1136 			break;
1137 	}
1138 	if (tmp != &urb->urb_list)
1139 		return -EIDRM;
1140 
1141 	/* Any status except -EINPROGRESS means something already started to
1142 	 * unlink this URB from the hardware.  So there's no more work to do.
1143 	 */
1144 	if (urb->unlinked)
1145 		return -EBUSY;
1146 	urb->unlinked = status;
1147 
1148 	/* IRQ setup can easily be broken so that USB controllers
1149 	 * never get completion IRQs ... maybe even the ones we need to
1150 	 * finish unlinking the initial failed usb_set_address()
1151 	 * or device descriptor fetch.
1152 	 */
1153 	if (!HCD_SAW_IRQ(hcd) && !is_root_hub(urb->dev)) {
1154 		dev_warn(hcd->self.controller, "Unlink after no-IRQ?  "
1155 			"Controller is probably using the wrong IRQ.\n");
1156 		set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
1157 	}
1158 
1159 	return 0;
1160 }
1161 EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb);
1162 
1163 /**
1164  * usb_hcd_unlink_urb_from_ep - remove an URB from its endpoint queue
1165  * @hcd: host controller to which @urb was submitted
1166  * @urb: URB being unlinked
1167  *
1168  * Host controller drivers should call this routine before calling
1169  * usb_hcd_giveback_urb().  The HCD's private spinlock must be held and
1170  * interrupts must be disabled.  The actions carried out here are required
1171  * for URB completion.
1172  */
1173 void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
1174 {
1175 	/* clear all state linking urb to this dev (and hcd) */
1176 	spin_lock(&hcd_urb_list_lock);
1177 	list_del_init(&urb->urb_list);
1178 	spin_unlock(&hcd_urb_list_lock);
1179 }
1180 EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);
1181 
1182 /*
1183  * Some usb host controllers can only perform dma using a small SRAM area.
1184  * The usb core itself is however optimized for host controllers that can dma
1185  * using regular system memory - like pci devices doing bus mastering.
1186  *
1187  * To support host controllers with limited dma capabilites we provide dma
1188  * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag.
1189  * For this to work properly the host controller code must first use the
1190  * function dma_declare_coherent_memory() to point out which memory area
1191  * that should be used for dma allocations.
1192  *
1193  * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for
1194  * dma using dma_alloc_coherent() which in turn allocates from the memory
1195  * area pointed out with dma_declare_coherent_memory().
1196  *
1197  * So, to summarize...
1198  *
1199  * - We need "local" memory, canonical example being
1200  *   a small SRAM on a discrete controller being the
1201  *   only memory that the controller can read ...
1202  *   (a) "normal" kernel memory is no good, and
1203  *   (b) there's not enough to share
1204  *
1205  * - The only *portable* hook for such stuff in the
1206  *   DMA framework is dma_declare_coherent_memory()
1207  *
1208  * - So we use that, even though the primary requirement
1209  *   is that the memory be "local" (hence addressible
1210  *   by that device), not "coherent".
1211  *
1212  */
1213 
1214 static int hcd_alloc_coherent(struct usb_bus *bus,
1215 			      gfp_t mem_flags, dma_addr_t *dma_handle,
1216 			      void **vaddr_handle, size_t size,
1217 			      enum dma_data_direction dir)
1218 {
1219 	unsigned char *vaddr;
1220 
1221 	if (*vaddr_handle == NULL) {
1222 		WARN_ON_ONCE(1);
1223 		return -EFAULT;
1224 	}
1225 
1226 	vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
1227 				 mem_flags, dma_handle);
1228 	if (!vaddr)
1229 		return -ENOMEM;
1230 
1231 	/*
1232 	 * Store the virtual address of the buffer at the end
1233 	 * of the allocated dma buffer. The size of the buffer
1234 	 * may be uneven so use unaligned functions instead
1235 	 * of just rounding up. It makes sense to optimize for
1236 	 * memory footprint over access speed since the amount
1237 	 * of memory available for dma may be limited.
1238 	 */
1239 	put_unaligned((unsigned long)*vaddr_handle,
1240 		      (unsigned long *)(vaddr + size));
1241 
1242 	if (dir == DMA_TO_DEVICE)
1243 		memcpy(vaddr, *vaddr_handle, size);
1244 
1245 	*vaddr_handle = vaddr;
1246 	return 0;
1247 }
1248 
1249 static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
1250 			      void **vaddr_handle, size_t size,
1251 			      enum dma_data_direction dir)
1252 {
1253 	unsigned char *vaddr = *vaddr_handle;
1254 
1255 	vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size));
1256 
1257 	if (dir == DMA_FROM_DEVICE)
1258 		memcpy(vaddr, *vaddr_handle, size);
1259 
1260 	hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle);
1261 
1262 	*vaddr_handle = vaddr;
1263 	*dma_handle = 0;
1264 }
1265 
1266 static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
1267 {
1268 	enum dma_data_direction dir;
1269 
1270 	if (urb->transfer_flags & URB_SETUP_MAP_SINGLE)
1271 		dma_unmap_single(hcd->self.controller,
1272 				urb->setup_dma,
1273 				sizeof(struct usb_ctrlrequest),
1274 				DMA_TO_DEVICE);
1275 	else if (urb->transfer_flags & URB_SETUP_MAP_LOCAL)
1276 		hcd_free_coherent(urb->dev->bus,
1277 				&urb->setup_dma,
1278 				(void **) &urb->setup_packet,
1279 				sizeof(struct usb_ctrlrequest),
1280 				DMA_TO_DEVICE);
1281 
1282 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1283 	if (urb->transfer_flags & URB_DMA_MAP_SG)
1284 		dma_unmap_sg(hcd->self.controller,
1285 				urb->sg,
1286 				urb->num_sgs,
1287 				dir);
1288 	else if (urb->transfer_flags & URB_DMA_MAP_PAGE)
1289 		dma_unmap_page(hcd->self.controller,
1290 				urb->transfer_dma,
1291 				urb->transfer_buffer_length,
1292 				dir);
1293 	else if (urb->transfer_flags & URB_DMA_MAP_SINGLE)
1294 		dma_unmap_single(hcd->self.controller,
1295 				urb->transfer_dma,
1296 				urb->transfer_buffer_length,
1297 				dir);
1298 	else if (urb->transfer_flags & URB_MAP_LOCAL)
1299 		hcd_free_coherent(urb->dev->bus,
1300 				&urb->transfer_dma,
1301 				&urb->transfer_buffer,
1302 				urb->transfer_buffer_length,
1303 				dir);
1304 
1305 	/* Make it safe to call this routine more than once */
1306 	urb->transfer_flags &= ~(URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
1307 			URB_DMA_MAP_SG | URB_DMA_MAP_PAGE |
1308 			URB_DMA_MAP_SINGLE | URB_MAP_LOCAL);
1309 }
1310 
1311 static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
1312 			   gfp_t mem_flags)
1313 {
1314 	enum dma_data_direction dir;
1315 	int ret = 0;
1316 
1317 	/* Map the URB's buffers for DMA access.
1318 	 * Lower level HCD code should use *_dma exclusively,
1319 	 * unless it uses pio or talks to another transport,
1320 	 * or uses the provided scatter gather list for bulk.
1321 	 */
1322 
1323 	if (usb_endpoint_xfer_control(&urb->ep->desc)) {
1324 		if (hcd->self.uses_dma) {
1325 			urb->setup_dma = dma_map_single(
1326 					hcd->self.controller,
1327 					urb->setup_packet,
1328 					sizeof(struct usb_ctrlrequest),
1329 					DMA_TO_DEVICE);
1330 			if (dma_mapping_error(hcd->self.controller,
1331 						urb->setup_dma))
1332 				return -EAGAIN;
1333 			urb->transfer_flags |= URB_SETUP_MAP_SINGLE;
1334 		} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
1335 			ret = hcd_alloc_coherent(
1336 					urb->dev->bus, mem_flags,
1337 					&urb->setup_dma,
1338 					(void **)&urb->setup_packet,
1339 					sizeof(struct usb_ctrlrequest),
1340 					DMA_TO_DEVICE);
1341 			if (ret)
1342 				return ret;
1343 			urb->transfer_flags |= URB_SETUP_MAP_LOCAL;
1344 		}
1345 	}
1346 
1347 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1348 	if (urb->transfer_buffer_length != 0
1349 	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
1350 		if (hcd->self.uses_dma) {
1351 			if (urb->num_sgs) {
1352 				int n = dma_map_sg(
1353 						hcd->self.controller,
1354 						urb->sg,
1355 						urb->num_sgs,
1356 						dir);
1357 				if (n <= 0)
1358 					ret = -EAGAIN;
1359 				else
1360 					urb->transfer_flags |= URB_DMA_MAP_SG;
1361 				if (n != urb->num_sgs) {
1362 					urb->num_sgs = n;
1363 					urb->transfer_flags |=
1364 							URB_DMA_SG_COMBINED;
1365 				}
1366 			} else if (urb->sg) {
1367 				struct scatterlist *sg = urb->sg;
1368 				urb->transfer_dma = dma_map_page(
1369 						hcd->self.controller,
1370 						sg_page(sg),
1371 						sg->offset,
1372 						urb->transfer_buffer_length,
1373 						dir);
1374 				if (dma_mapping_error(hcd->self.controller,
1375 						urb->transfer_dma))
1376 					ret = -EAGAIN;
1377 				else
1378 					urb->transfer_flags |= URB_DMA_MAP_PAGE;
1379 			} else {
1380 				urb->transfer_dma = dma_map_single(
1381 						hcd->self.controller,
1382 						urb->transfer_buffer,
1383 						urb->transfer_buffer_length,
1384 						dir);
1385 				if (dma_mapping_error(hcd->self.controller,
1386 						urb->transfer_dma))
1387 					ret = -EAGAIN;
1388 				else
1389 					urb->transfer_flags |= URB_DMA_MAP_SINGLE;
1390 			}
1391 		} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
1392 			ret = hcd_alloc_coherent(
1393 					urb->dev->bus, mem_flags,
1394 					&urb->transfer_dma,
1395 					&urb->transfer_buffer,
1396 					urb->transfer_buffer_length,
1397 					dir);
1398 			if (ret == 0)
1399 				urb->transfer_flags |= URB_MAP_LOCAL;
1400 		}
1401 		if (ret && (urb->transfer_flags & (URB_SETUP_MAP_SINGLE |
1402 				URB_SETUP_MAP_LOCAL)))
1403 			unmap_urb_for_dma(hcd, urb);
1404 	}
1405 	return ret;
1406 }
1407 
1408 /*-------------------------------------------------------------------------*/
1409 
1410 /* may be called in any context with a valid urb->dev usecount
1411  * caller surrenders "ownership" of urb
1412  * expects usb_submit_urb() to have sanity checked and conditioned all
1413  * inputs in the urb
1414  */
1415 int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
1416 {
1417 	int			status;
1418 	struct usb_hcd		*hcd = bus_to_hcd(urb->dev->bus);
1419 
1420 	/* increment urb's reference count as part of giving it to the HCD
1421 	 * (which will control it).  HCD guarantees that it either returns
1422 	 * an error or calls giveback(), but not both.
1423 	 */
1424 	usb_get_urb(urb);
1425 	atomic_inc(&urb->use_count);
1426 	atomic_inc(&urb->dev->urbnum);
1427 	usbmon_urb_submit(&hcd->self, urb);
1428 
1429 	/* NOTE requirements on root-hub callers (usbfs and the hub
1430 	 * driver, for now):  URBs' urb->transfer_buffer must be
1431 	 * valid and usb_buffer_{sync,unmap}() not be needed, since
1432 	 * they could clobber root hub response data.  Also, control
1433 	 * URBs must be submitted in process context with interrupts
1434 	 * enabled.
1435 	 */
1436 
1437 	if (is_root_hub(urb->dev)) {
1438 		status = rh_urb_enqueue(hcd, urb);
1439 	} else {
1440 		status = map_urb_for_dma(hcd, urb, mem_flags);
1441 		if (likely(status == 0)) {
1442 			status = hcd->driver->urb_enqueue(hcd, urb, mem_flags);
1443 			if (unlikely(status))
1444 				unmap_urb_for_dma(hcd, urb);
1445 		}
1446 	}
1447 
1448 	if (unlikely(status)) {
1449 		usbmon_urb_submit_error(&hcd->self, urb, status);
1450 		urb->hcpriv = NULL;
1451 		INIT_LIST_HEAD(&urb->urb_list);
1452 		atomic_dec(&urb->use_count);
1453 		atomic_dec(&urb->dev->urbnum);
1454 		if (atomic_read(&urb->reject))
1455 			wake_up(&usb_kill_urb_queue);
1456 		usb_put_urb(urb);
1457 	}
1458 	return status;
1459 }
1460 
1461 /*-------------------------------------------------------------------------*/
1462 
1463 /* this makes the hcd giveback() the urb more quickly, by kicking it
1464  * off hardware queues (which may take a while) and returning it as
1465  * soon as practical.  we've already set up the urb's return status,
1466  * but we can't know if the callback completed already.
1467  */
1468 static int unlink1(struct usb_hcd *hcd, struct urb *urb, int status)
1469 {
1470 	int		value;
1471 
1472 	if (is_root_hub(urb->dev))
1473 		value = usb_rh_urb_dequeue(hcd, urb, status);
1474 	else {
1475 
1476 		/* The only reason an HCD might fail this call is if
1477 		 * it has not yet fully queued the urb to begin with.
1478 		 * Such failures should be harmless. */
1479 		value = hcd->driver->urb_dequeue(hcd, urb, status);
1480 	}
1481 	return value;
1482 }
1483 
1484 /*
1485  * called in any context
1486  *
1487  * caller guarantees urb won't be recycled till both unlink()
1488  * and the urb's completion function return
1489  */
1490 int usb_hcd_unlink_urb (struct urb *urb, int status)
1491 {
1492 	struct usb_hcd		*hcd;
1493 	int			retval = -EIDRM;
1494 	unsigned long		flags;
1495 
1496 	/* Prevent the device and bus from going away while
1497 	 * the unlink is carried out.  If they are already gone
1498 	 * then urb->use_count must be 0, since disconnected
1499 	 * devices can't have any active URBs.
1500 	 */
1501 	spin_lock_irqsave(&hcd_urb_unlink_lock, flags);
1502 	if (atomic_read(&urb->use_count) > 0) {
1503 		retval = 0;
1504 		usb_get_dev(urb->dev);
1505 	}
1506 	spin_unlock_irqrestore(&hcd_urb_unlink_lock, flags);
1507 	if (retval == 0) {
1508 		hcd = bus_to_hcd(urb->dev->bus);
1509 		retval = unlink1(hcd, urb, status);
1510 		usb_put_dev(urb->dev);
1511 	}
1512 
1513 	if (retval == 0)
1514 		retval = -EINPROGRESS;
1515 	else if (retval != -EIDRM && retval != -EBUSY)
1516 		dev_dbg(&urb->dev->dev, "hcd_unlink_urb %p fail %d\n",
1517 				urb, retval);
1518 	return retval;
1519 }
1520 
1521 /*-------------------------------------------------------------------------*/
1522 
1523 /**
1524  * usb_hcd_giveback_urb - return URB from HCD to device driver
1525  * @hcd: host controller returning the URB
1526  * @urb: urb being returned to the USB device driver.
1527  * @status: completion status code for the URB.
1528  * Context: in_interrupt()
1529  *
1530  * This hands the URB from HCD to its USB device driver, using its
1531  * completion function.  The HCD has freed all per-urb resources
1532  * (and is done using urb->hcpriv).  It also released all HCD locks;
1533  * the device driver won't cause problems if it frees, modifies,
1534  * or resubmits this URB.
1535  *
1536  * If @urb was unlinked, the value of @status will be overridden by
1537  * @urb->unlinked.  Erroneous short transfers are detected in case
1538  * the HCD hasn't checked for them.
1539  */
1540 void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
1541 {
1542 	urb->hcpriv = NULL;
1543 	if (unlikely(urb->unlinked))
1544 		status = urb->unlinked;
1545 	else if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
1546 			urb->actual_length < urb->transfer_buffer_length &&
1547 			!status))
1548 		status = -EREMOTEIO;
1549 
1550 	unmap_urb_for_dma(hcd, urb);
1551 	usbmon_urb_complete(&hcd->self, urb, status);
1552 	usb_unanchor_urb(urb);
1553 
1554 	/* pass ownership to the completion handler */
1555 	urb->status = status;
1556 	urb->complete (urb);
1557 	atomic_dec (&urb->use_count);
1558 	if (unlikely(atomic_read(&urb->reject)))
1559 		wake_up (&usb_kill_urb_queue);
1560 	usb_put_urb (urb);
1561 }
1562 EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb);
1563 
1564 /*-------------------------------------------------------------------------*/
1565 
1566 /* Cancel all URBs pending on this endpoint and wait for the endpoint's
1567  * queue to drain completely.  The caller must first insure that no more
1568  * URBs can be submitted for this endpoint.
1569  */
1570 void usb_hcd_flush_endpoint(struct usb_device *udev,
1571 		struct usb_host_endpoint *ep)
1572 {
1573 	struct usb_hcd		*hcd;
1574 	struct urb		*urb;
1575 
1576 	if (!ep)
1577 		return;
1578 	might_sleep();
1579 	hcd = bus_to_hcd(udev->bus);
1580 
1581 	/* No more submits can occur */
1582 	spin_lock_irq(&hcd_urb_list_lock);
1583 rescan:
1584 	list_for_each_entry (urb, &ep->urb_list, urb_list) {
1585 		int	is_in;
1586 
1587 		if (urb->unlinked)
1588 			continue;
1589 		usb_get_urb (urb);
1590 		is_in = usb_urb_dir_in(urb);
1591 		spin_unlock(&hcd_urb_list_lock);
1592 
1593 		/* kick hcd */
1594 		unlink1(hcd, urb, -ESHUTDOWN);
1595 		dev_dbg (hcd->self.controller,
1596 			"shutdown urb %p ep%d%s%s\n",
1597 			urb, usb_endpoint_num(&ep->desc),
1598 			is_in ? "in" : "out",
1599 			({	char *s;
1600 
1601 				 switch (usb_endpoint_type(&ep->desc)) {
1602 				 case USB_ENDPOINT_XFER_CONTROL:
1603 					s = ""; break;
1604 				 case USB_ENDPOINT_XFER_BULK:
1605 					s = "-bulk"; break;
1606 				 case USB_ENDPOINT_XFER_INT:
1607 					s = "-intr"; break;
1608 				 default:
1609 			 		s = "-iso"; break;
1610 				};
1611 				s;
1612 			}));
1613 		usb_put_urb (urb);
1614 
1615 		/* list contents may have changed */
1616 		spin_lock(&hcd_urb_list_lock);
1617 		goto rescan;
1618 	}
1619 	spin_unlock_irq(&hcd_urb_list_lock);
1620 
1621 	/* Wait until the endpoint queue is completely empty */
1622 	while (!list_empty (&ep->urb_list)) {
1623 		spin_lock_irq(&hcd_urb_list_lock);
1624 
1625 		/* The list may have changed while we acquired the spinlock */
1626 		urb = NULL;
1627 		if (!list_empty (&ep->urb_list)) {
1628 			urb = list_entry (ep->urb_list.prev, struct urb,
1629 					urb_list);
1630 			usb_get_urb (urb);
1631 		}
1632 		spin_unlock_irq(&hcd_urb_list_lock);
1633 
1634 		if (urb) {
1635 			usb_kill_urb (urb);
1636 			usb_put_urb (urb);
1637 		}
1638 	}
1639 }
1640 
1641 /**
1642  * usb_hcd_alloc_bandwidth - check whether a new bandwidth setting exceeds
1643  *				the bus bandwidth
1644  * @udev: target &usb_device
1645  * @new_config: new configuration to install
1646  * @cur_alt: the current alternate interface setting
1647  * @new_alt: alternate interface setting that is being installed
1648  *
1649  * To change configurations, pass in the new configuration in new_config,
1650  * and pass NULL for cur_alt and new_alt.
1651  *
1652  * To reset a device's configuration (put the device in the ADDRESSED state),
1653  * pass in NULL for new_config, cur_alt, and new_alt.
1654  *
1655  * To change alternate interface settings, pass in NULL for new_config,
1656  * pass in the current alternate interface setting in cur_alt,
1657  * and pass in the new alternate interface setting in new_alt.
1658  *
1659  * Returns an error if the requested bandwidth change exceeds the
1660  * bus bandwidth or host controller internal resources.
1661  */
1662 int usb_hcd_alloc_bandwidth(struct usb_device *udev,
1663 		struct usb_host_config *new_config,
1664 		struct usb_host_interface *cur_alt,
1665 		struct usb_host_interface *new_alt)
1666 {
1667 	int num_intfs, i, j;
1668 	struct usb_host_interface *alt = NULL;
1669 	int ret = 0;
1670 	struct usb_hcd *hcd;
1671 	struct usb_host_endpoint *ep;
1672 
1673 	hcd = bus_to_hcd(udev->bus);
1674 	if (!hcd->driver->check_bandwidth)
1675 		return 0;
1676 
1677 	/* Configuration is being removed - set configuration 0 */
1678 	if (!new_config && !cur_alt) {
1679 		for (i = 1; i < 16; ++i) {
1680 			ep = udev->ep_out[i];
1681 			if (ep)
1682 				hcd->driver->drop_endpoint(hcd, udev, ep);
1683 			ep = udev->ep_in[i];
1684 			if (ep)
1685 				hcd->driver->drop_endpoint(hcd, udev, ep);
1686 		}
1687 		hcd->driver->check_bandwidth(hcd, udev);
1688 		return 0;
1689 	}
1690 	/* Check if the HCD says there's enough bandwidth.  Enable all endpoints
1691 	 * each interface's alt setting 0 and ask the HCD to check the bandwidth
1692 	 * of the bus.  There will always be bandwidth for endpoint 0, so it's
1693 	 * ok to exclude it.
1694 	 */
1695 	if (new_config) {
1696 		num_intfs = new_config->desc.bNumInterfaces;
1697 		/* Remove endpoints (except endpoint 0, which is always on the
1698 		 * schedule) from the old config from the schedule
1699 		 */
1700 		for (i = 1; i < 16; ++i) {
1701 			ep = udev->ep_out[i];
1702 			if (ep) {
1703 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1704 				if (ret < 0)
1705 					goto reset;
1706 			}
1707 			ep = udev->ep_in[i];
1708 			if (ep) {
1709 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1710 				if (ret < 0)
1711 					goto reset;
1712 			}
1713 		}
1714 		for (i = 0; i < num_intfs; ++i) {
1715 			struct usb_host_interface *first_alt;
1716 			int iface_num;
1717 
1718 			first_alt = &new_config->intf_cache[i]->altsetting[0];
1719 			iface_num = first_alt->desc.bInterfaceNumber;
1720 			/* Set up endpoints for alternate interface setting 0 */
1721 			alt = usb_find_alt_setting(new_config, iface_num, 0);
1722 			if (!alt)
1723 				/* No alt setting 0? Pick the first setting. */
1724 				alt = first_alt;
1725 
1726 			for (j = 0; j < alt->desc.bNumEndpoints; j++) {
1727 				ret = hcd->driver->add_endpoint(hcd, udev, &alt->endpoint[j]);
1728 				if (ret < 0)
1729 					goto reset;
1730 			}
1731 		}
1732 	}
1733 	if (cur_alt && new_alt) {
1734 		struct usb_interface *iface = usb_ifnum_to_if(udev,
1735 				cur_alt->desc.bInterfaceNumber);
1736 
1737 		if (iface->resetting_device) {
1738 			/*
1739 			 * The USB core just reset the device, so the xHCI host
1740 			 * and the device will think alt setting 0 is installed.
1741 			 * However, the USB core will pass in the alternate
1742 			 * setting installed before the reset as cur_alt.  Dig
1743 			 * out the alternate setting 0 structure, or the first
1744 			 * alternate setting if a broken device doesn't have alt
1745 			 * setting 0.
1746 			 */
1747 			cur_alt = usb_altnum_to_altsetting(iface, 0);
1748 			if (!cur_alt)
1749 				cur_alt = &iface->altsetting[0];
1750 		}
1751 
1752 		/* Drop all the endpoints in the current alt setting */
1753 		for (i = 0; i < cur_alt->desc.bNumEndpoints; i++) {
1754 			ret = hcd->driver->drop_endpoint(hcd, udev,
1755 					&cur_alt->endpoint[i]);
1756 			if (ret < 0)
1757 				goto reset;
1758 		}
1759 		/* Add all the endpoints in the new alt setting */
1760 		for (i = 0; i < new_alt->desc.bNumEndpoints; i++) {
1761 			ret = hcd->driver->add_endpoint(hcd, udev,
1762 					&new_alt->endpoint[i]);
1763 			if (ret < 0)
1764 				goto reset;
1765 		}
1766 	}
1767 	ret = hcd->driver->check_bandwidth(hcd, udev);
1768 reset:
1769 	if (ret < 0)
1770 		hcd->driver->reset_bandwidth(hcd, udev);
1771 	return ret;
1772 }
1773 
1774 /* Disables the endpoint: synchronizes with the hcd to make sure all
1775  * endpoint state is gone from hardware.  usb_hcd_flush_endpoint() must
1776  * have been called previously.  Use for set_configuration, set_interface,
1777  * driver removal, physical disconnect.
1778  *
1779  * example:  a qh stored in ep->hcpriv, holding state related to endpoint
1780  * type, maxpacket size, toggle, halt status, and scheduling.
1781  */
1782 void usb_hcd_disable_endpoint(struct usb_device *udev,
1783 		struct usb_host_endpoint *ep)
1784 {
1785 	struct usb_hcd		*hcd;
1786 
1787 	might_sleep();
1788 	hcd = bus_to_hcd(udev->bus);
1789 	if (hcd->driver->endpoint_disable)
1790 		hcd->driver->endpoint_disable(hcd, ep);
1791 }
1792 
1793 /**
1794  * usb_hcd_reset_endpoint - reset host endpoint state
1795  * @udev: USB device.
1796  * @ep:   the endpoint to reset.
1797  *
1798  * Resets any host endpoint state such as the toggle bit, sequence
1799  * number and current window.
1800  */
1801 void usb_hcd_reset_endpoint(struct usb_device *udev,
1802 			    struct usb_host_endpoint *ep)
1803 {
1804 	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
1805 
1806 	if (hcd->driver->endpoint_reset)
1807 		hcd->driver->endpoint_reset(hcd, ep);
1808 	else {
1809 		int epnum = usb_endpoint_num(&ep->desc);
1810 		int is_out = usb_endpoint_dir_out(&ep->desc);
1811 		int is_control = usb_endpoint_xfer_control(&ep->desc);
1812 
1813 		usb_settoggle(udev, epnum, is_out, 0);
1814 		if (is_control)
1815 			usb_settoggle(udev, epnum, !is_out, 0);
1816 	}
1817 }
1818 
1819 /**
1820  * usb_alloc_streams - allocate bulk endpoint stream IDs.
1821  * @interface:		alternate setting that includes all endpoints.
1822  * @eps:		array of endpoints that need streams.
1823  * @num_eps:		number of endpoints in the array.
1824  * @num_streams:	number of streams to allocate.
1825  * @mem_flags:		flags hcd should use to allocate memory.
1826  *
1827  * Sets up a group of bulk endpoints to have num_streams stream IDs available.
1828  * Drivers may queue multiple transfers to different stream IDs, which may
1829  * complete in a different order than they were queued.
1830  */
1831 int usb_alloc_streams(struct usb_interface *interface,
1832 		struct usb_host_endpoint **eps, unsigned int num_eps,
1833 		unsigned int num_streams, gfp_t mem_flags)
1834 {
1835 	struct usb_hcd *hcd;
1836 	struct usb_device *dev;
1837 	int i;
1838 
1839 	dev = interface_to_usbdev(interface);
1840 	hcd = bus_to_hcd(dev->bus);
1841 	if (!hcd->driver->alloc_streams || !hcd->driver->free_streams)
1842 		return -EINVAL;
1843 	if (dev->speed != USB_SPEED_SUPER)
1844 		return -EINVAL;
1845 
1846 	/* Streams only apply to bulk endpoints. */
1847 	for (i = 0; i < num_eps; i++)
1848 		if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
1849 			return -EINVAL;
1850 
1851 	return hcd->driver->alloc_streams(hcd, dev, eps, num_eps,
1852 			num_streams, mem_flags);
1853 }
1854 EXPORT_SYMBOL_GPL(usb_alloc_streams);
1855 
1856 /**
1857  * usb_free_streams - free bulk endpoint stream IDs.
1858  * @interface:	alternate setting that includes all endpoints.
1859  * @eps:	array of endpoints to remove streams from.
1860  * @num_eps:	number of endpoints in the array.
1861  * @mem_flags:	flags hcd should use to allocate memory.
1862  *
1863  * Reverts a group of bulk endpoints back to not using stream IDs.
1864  * Can fail if we are given bad arguments, or HCD is broken.
1865  */
1866 void usb_free_streams(struct usb_interface *interface,
1867 		struct usb_host_endpoint **eps, unsigned int num_eps,
1868 		gfp_t mem_flags)
1869 {
1870 	struct usb_hcd *hcd;
1871 	struct usb_device *dev;
1872 	int i;
1873 
1874 	dev = interface_to_usbdev(interface);
1875 	hcd = bus_to_hcd(dev->bus);
1876 	if (dev->speed != USB_SPEED_SUPER)
1877 		return;
1878 
1879 	/* Streams only apply to bulk endpoints. */
1880 	for (i = 0; i < num_eps; i++)
1881 		if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
1882 			return;
1883 
1884 	hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
1885 }
1886 EXPORT_SYMBOL_GPL(usb_free_streams);
1887 
1888 /* Protect against drivers that try to unlink URBs after the device
1889  * is gone, by waiting until all unlinks for @udev are finished.
1890  * Since we don't currently track URBs by device, simply wait until
1891  * nothing is running in the locked region of usb_hcd_unlink_urb().
1892  */
1893 void usb_hcd_synchronize_unlinks(struct usb_device *udev)
1894 {
1895 	spin_lock_irq(&hcd_urb_unlink_lock);
1896 	spin_unlock_irq(&hcd_urb_unlink_lock);
1897 }
1898 
1899 /*-------------------------------------------------------------------------*/
1900 
1901 /* called in any context */
1902 int usb_hcd_get_frame_number (struct usb_device *udev)
1903 {
1904 	struct usb_hcd	*hcd = bus_to_hcd(udev->bus);
1905 
1906 	if (!HC_IS_RUNNING (hcd->state))
1907 		return -ESHUTDOWN;
1908 	return hcd->driver->get_frame_number (hcd);
1909 }
1910 
1911 /*-------------------------------------------------------------------------*/
1912 
1913 #ifdef	CONFIG_PM
1914 
1915 int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg)
1916 {
1917 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
1918 	int		status;
1919 	int		old_state = hcd->state;
1920 
1921 	dev_dbg(&rhdev->dev, "bus %s%s\n",
1922 			(msg.event & PM_EVENT_AUTO ? "auto-" : ""), "suspend");
1923 	if (!hcd->driver->bus_suspend) {
1924 		status = -ENOENT;
1925 	} else {
1926 		hcd->state = HC_STATE_QUIESCING;
1927 		status = hcd->driver->bus_suspend(hcd);
1928 	}
1929 	if (status == 0) {
1930 		usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
1931 		hcd->state = HC_STATE_SUSPENDED;
1932 	} else {
1933 		hcd->state = old_state;
1934 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
1935 				"suspend", status);
1936 	}
1937 	return status;
1938 }
1939 
1940 int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
1941 {
1942 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
1943 	int		status;
1944 	int		old_state = hcd->state;
1945 
1946 	dev_dbg(&rhdev->dev, "usb %s%s\n",
1947 			(msg.event & PM_EVENT_AUTO ? "auto-" : ""), "resume");
1948 	clear_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
1949 	if (!hcd->driver->bus_resume)
1950 		return -ENOENT;
1951 	if (hcd->state == HC_STATE_RUNNING)
1952 		return 0;
1953 
1954 	hcd->state = HC_STATE_RESUMING;
1955 	status = hcd->driver->bus_resume(hcd);
1956 	if (status == 0) {
1957 		/* TRSMRCY = 10 msec */
1958 		msleep(10);
1959 		usb_set_device_state(rhdev, rhdev->actconfig
1960 				? USB_STATE_CONFIGURED
1961 				: USB_STATE_ADDRESS);
1962 		hcd->state = HC_STATE_RUNNING;
1963 	} else {
1964 		hcd->state = old_state;
1965 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
1966 				"resume", status);
1967 		if (status != -ESHUTDOWN)
1968 			usb_hc_died(hcd);
1969 	}
1970 	return status;
1971 }
1972 
1973 #endif	/* CONFIG_PM */
1974 
1975 #ifdef	CONFIG_USB_SUSPEND
1976 
1977 /* Workqueue routine for root-hub remote wakeup */
1978 static void hcd_resume_work(struct work_struct *work)
1979 {
1980 	struct usb_hcd *hcd = container_of(work, struct usb_hcd, wakeup_work);
1981 	struct usb_device *udev = hcd->self.root_hub;
1982 
1983 	usb_lock_device(udev);
1984 	usb_remote_wakeup(udev);
1985 	usb_unlock_device(udev);
1986 }
1987 
1988 /**
1989  * usb_hcd_resume_root_hub - called by HCD to resume its root hub
1990  * @hcd: host controller for this root hub
1991  *
1992  * The USB host controller calls this function when its root hub is
1993  * suspended (with the remote wakeup feature enabled) and a remote
1994  * wakeup request is received.  The routine submits a workqueue request
1995  * to resume the root hub (that is, manage its downstream ports again).
1996  */
1997 void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
1998 {
1999 	unsigned long flags;
2000 
2001 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
2002 	if (hcd->rh_registered) {
2003 		set_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
2004 		queue_work(pm_wq, &hcd->wakeup_work);
2005 	}
2006 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
2007 }
2008 EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hub);
2009 
2010 #endif	/* CONFIG_USB_SUSPEND */
2011 
2012 /*-------------------------------------------------------------------------*/
2013 
2014 #ifdef	CONFIG_USB_OTG
2015 
2016 /**
2017  * usb_bus_start_enum - start immediate enumeration (for OTG)
2018  * @bus: the bus (must use hcd framework)
2019  * @port_num: 1-based number of port; usually bus->otg_port
2020  * Context: in_interrupt()
2021  *
2022  * Starts enumeration, with an immediate reset followed later by
2023  * khubd identifying and possibly configuring the device.
2024  * This is needed by OTG controller drivers, where it helps meet
2025  * HNP protocol timing requirements for starting a port reset.
2026  */
2027 int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num)
2028 {
2029 	struct usb_hcd		*hcd;
2030 	int			status = -EOPNOTSUPP;
2031 
2032 	/* NOTE: since HNP can't start by grabbing the bus's address0_sem,
2033 	 * boards with root hubs hooked up to internal devices (instead of
2034 	 * just the OTG port) may need more attention to resetting...
2035 	 */
2036 	hcd = container_of (bus, struct usb_hcd, self);
2037 	if (port_num && hcd->driver->start_port_reset)
2038 		status = hcd->driver->start_port_reset(hcd, port_num);
2039 
2040 	/* run khubd shortly after (first) root port reset finishes;
2041 	 * it may issue others, until at least 50 msecs have passed.
2042 	 */
2043 	if (status == 0)
2044 		mod_timer(&hcd->rh_timer, jiffies + msecs_to_jiffies(10));
2045 	return status;
2046 }
2047 EXPORT_SYMBOL_GPL(usb_bus_start_enum);
2048 
2049 #endif
2050 
2051 /*-------------------------------------------------------------------------*/
2052 
2053 /**
2054  * usb_hcd_irq - hook IRQs to HCD framework (bus glue)
2055  * @irq: the IRQ being raised
2056  * @__hcd: pointer to the HCD whose IRQ is being signaled
2057  *
2058  * If the controller isn't HALTed, calls the driver's irq handler.
2059  * Checks whether the controller is now dead.
2060  */
2061 irqreturn_t usb_hcd_irq (int irq, void *__hcd)
2062 {
2063 	struct usb_hcd		*hcd = __hcd;
2064 	unsigned long		flags;
2065 	irqreturn_t		rc;
2066 
2067 	/* IRQF_DISABLED doesn't work correctly with shared IRQs
2068 	 * when the first handler doesn't use it.  So let's just
2069 	 * assume it's never used.
2070 	 */
2071 	local_irq_save(flags);
2072 
2073 	if (unlikely(hcd->state == HC_STATE_HALT || !HCD_HW_ACCESSIBLE(hcd))) {
2074 		rc = IRQ_NONE;
2075 	} else if (hcd->driver->irq(hcd) == IRQ_NONE) {
2076 		rc = IRQ_NONE;
2077 	} else {
2078 		set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
2079 
2080 		if (unlikely(hcd->state == HC_STATE_HALT))
2081 			usb_hc_died(hcd);
2082 		rc = IRQ_HANDLED;
2083 	}
2084 
2085 	local_irq_restore(flags);
2086 	return rc;
2087 }
2088 EXPORT_SYMBOL_GPL(usb_hcd_irq);
2089 
2090 /*-------------------------------------------------------------------------*/
2091 
2092 /**
2093  * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
2094  * @hcd: pointer to the HCD representing the controller
2095  *
2096  * This is called by bus glue to report a USB host controller that died
2097  * while operations may still have been pending.  It's called automatically
2098  * by the PCI glue, so only glue for non-PCI busses should need to call it.
2099  */
2100 void usb_hc_died (struct usb_hcd *hcd)
2101 {
2102 	unsigned long flags;
2103 
2104 	dev_err (hcd->self.controller, "HC died; cleaning up\n");
2105 
2106 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
2107 	if (hcd->rh_registered) {
2108 		clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2109 
2110 		/* make khubd clean up old urbs and devices */
2111 		usb_set_device_state (hcd->self.root_hub,
2112 				USB_STATE_NOTATTACHED);
2113 		usb_kick_khubd (hcd->self.root_hub);
2114 	}
2115 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
2116 }
2117 EXPORT_SYMBOL_GPL (usb_hc_died);
2118 
2119 /*-------------------------------------------------------------------------*/
2120 
2121 /**
2122  * usb_create_hcd - create and initialize an HCD structure
2123  * @driver: HC driver that will use this hcd
2124  * @dev: device for this HC, stored in hcd->self.controller
2125  * @bus_name: value to store in hcd->self.bus_name
2126  * Context: !in_interrupt()
2127  *
2128  * Allocate a struct usb_hcd, with extra space at the end for the
2129  * HC driver's private data.  Initialize the generic members of the
2130  * hcd structure.
2131  *
2132  * If memory is unavailable, returns NULL.
2133  */
2134 struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
2135 		struct device *dev, const char *bus_name)
2136 {
2137 	struct usb_hcd *hcd;
2138 
2139 	hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
2140 	if (!hcd) {
2141 		dev_dbg (dev, "hcd alloc failed\n");
2142 		return NULL;
2143 	}
2144 	dev_set_drvdata(dev, hcd);
2145 	kref_init(&hcd->kref);
2146 
2147 	usb_bus_init(&hcd->self);
2148 	hcd->self.controller = dev;
2149 	hcd->self.bus_name = bus_name;
2150 	hcd->self.uses_dma = (dev->dma_mask != NULL);
2151 
2152 	init_timer(&hcd->rh_timer);
2153 	hcd->rh_timer.function = rh_timer_func;
2154 	hcd->rh_timer.data = (unsigned long) hcd;
2155 #ifdef CONFIG_USB_SUSPEND
2156 	INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
2157 #endif
2158 	mutex_init(&hcd->bandwidth_mutex);
2159 
2160 	hcd->driver = driver;
2161 	hcd->product_desc = (driver->product_desc) ? driver->product_desc :
2162 			"USB Host Controller";
2163 	return hcd;
2164 }
2165 EXPORT_SYMBOL_GPL(usb_create_hcd);
2166 
2167 static void hcd_release (struct kref *kref)
2168 {
2169 	struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);
2170 
2171 	kfree(hcd);
2172 }
2173 
2174 struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd)
2175 {
2176 	if (hcd)
2177 		kref_get (&hcd->kref);
2178 	return hcd;
2179 }
2180 EXPORT_SYMBOL_GPL(usb_get_hcd);
2181 
2182 void usb_put_hcd (struct usb_hcd *hcd)
2183 {
2184 	if (hcd)
2185 		kref_put (&hcd->kref, hcd_release);
2186 }
2187 EXPORT_SYMBOL_GPL(usb_put_hcd);
2188 
2189 /**
2190  * usb_add_hcd - finish generic HCD structure initialization and register
2191  * @hcd: the usb_hcd structure to initialize
2192  * @irqnum: Interrupt line to allocate
2193  * @irqflags: Interrupt type flags
2194  *
2195  * Finish the remaining parts of generic HCD initialization: allocate the
2196  * buffers of consistent memory, register the bus, request the IRQ line,
2197  * and call the driver's reset() and start() routines.
2198  */
2199 int usb_add_hcd(struct usb_hcd *hcd,
2200 		unsigned int irqnum, unsigned long irqflags)
2201 {
2202 	int retval;
2203 	struct usb_device *rhdev;
2204 
2205 	dev_info(hcd->self.controller, "%s\n", hcd->product_desc);
2206 
2207 	hcd->authorized_default = hcd->wireless? 0 : 1;
2208 	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
2209 
2210 	/* HC is in reset state, but accessible.  Now do the one-time init,
2211 	 * bottom up so that hcds can customize the root hubs before khubd
2212 	 * starts talking to them.  (Note, bus id is assigned early too.)
2213 	 */
2214 	if ((retval = hcd_buffer_create(hcd)) != 0) {
2215 		dev_dbg(hcd->self.controller, "pool alloc failed\n");
2216 		return retval;
2217 	}
2218 
2219 	if ((retval = usb_register_bus(&hcd->self)) < 0)
2220 		goto err_register_bus;
2221 
2222 	if ((rhdev = usb_alloc_dev(NULL, &hcd->self, 0)) == NULL) {
2223 		dev_err(hcd->self.controller, "unable to allocate root hub\n");
2224 		retval = -ENOMEM;
2225 		goto err_allocate_root_hub;
2226 	}
2227 	hcd->self.root_hub = rhdev;
2228 
2229 	switch (hcd->driver->flags & HCD_MASK) {
2230 	case HCD_USB11:
2231 		rhdev->speed = USB_SPEED_FULL;
2232 		break;
2233 	case HCD_USB2:
2234 		rhdev->speed = USB_SPEED_HIGH;
2235 		break;
2236 	case HCD_USB3:
2237 		rhdev->speed = USB_SPEED_SUPER;
2238 		break;
2239 	default:
2240 		goto err_set_rh_speed;
2241 	}
2242 
2243 	/* wakeup flag init defaults to "everything works" for root hubs,
2244 	 * but drivers can override it in reset() if needed, along with
2245 	 * recording the overall controller's system wakeup capability.
2246 	 */
2247 	device_init_wakeup(&rhdev->dev, 1);
2248 
2249 	/* "reset" is misnamed; its role is now one-time init. the controller
2250 	 * should already have been reset (and boot firmware kicked off etc).
2251 	 */
2252 	if (hcd->driver->reset && (retval = hcd->driver->reset(hcd)) < 0) {
2253 		dev_err(hcd->self.controller, "can't setup\n");
2254 		goto err_hcd_driver_setup;
2255 	}
2256 	hcd->rh_pollable = 1;
2257 
2258 	/* NOTE: root hub and controller capabilities may not be the same */
2259 	if (device_can_wakeup(hcd->self.controller)
2260 			&& device_can_wakeup(&hcd->self.root_hub->dev))
2261 		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
2262 
2263 	/* enable irqs just before we start the controller */
2264 	if (hcd->driver->irq) {
2265 
2266 		/* IRQF_DISABLED doesn't work as advertised when used together
2267 		 * with IRQF_SHARED. As usb_hcd_irq() will always disable
2268 		 * interrupts we can remove it here.
2269 		 */
2270 		if (irqflags & IRQF_SHARED)
2271 			irqflags &= ~IRQF_DISABLED;
2272 
2273 		snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
2274 				hcd->driver->description, hcd->self.busnum);
2275 		if ((retval = request_irq(irqnum, &usb_hcd_irq, irqflags,
2276 				hcd->irq_descr, hcd)) != 0) {
2277 			dev_err(hcd->self.controller,
2278 					"request interrupt %d failed\n", irqnum);
2279 			goto err_request_irq;
2280 		}
2281 		hcd->irq = irqnum;
2282 		dev_info(hcd->self.controller, "irq %d, %s 0x%08llx\n", irqnum,
2283 				(hcd->driver->flags & HCD_MEMORY) ?
2284 					"io mem" : "io base",
2285 					(unsigned long long)hcd->rsrc_start);
2286 	} else {
2287 		hcd->irq = -1;
2288 		if (hcd->rsrc_start)
2289 			dev_info(hcd->self.controller, "%s 0x%08llx\n",
2290 					(hcd->driver->flags & HCD_MEMORY) ?
2291 					"io mem" : "io base",
2292 					(unsigned long long)hcd->rsrc_start);
2293 	}
2294 
2295 	if ((retval = hcd->driver->start(hcd)) < 0) {
2296 		dev_err(hcd->self.controller, "startup error %d\n", retval);
2297 		goto err_hcd_driver_start;
2298 	}
2299 
2300 	/* starting here, usbcore will pay attention to this root hub */
2301 	rhdev->bus_mA = min(500u, hcd->power_budget);
2302 	if ((retval = register_root_hub(hcd)) != 0)
2303 		goto err_register_root_hub;
2304 
2305 	retval = sysfs_create_group(&rhdev->dev.kobj, &usb_bus_attr_group);
2306 	if (retval < 0) {
2307 		printk(KERN_ERR "Cannot register USB bus sysfs attributes: %d\n",
2308 		       retval);
2309 		goto error_create_attr_group;
2310 	}
2311 	if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
2312 		usb_hcd_poll_rh_status(hcd);
2313 	return retval;
2314 
2315 error_create_attr_group:
2316 	if (HC_IS_RUNNING(hcd->state))
2317 		hcd->state = HC_STATE_QUIESCING;
2318 	spin_lock_irq(&hcd_root_hub_lock);
2319 	hcd->rh_registered = 0;
2320 	spin_unlock_irq(&hcd_root_hub_lock);
2321 
2322 #ifdef CONFIG_USB_SUSPEND
2323 	cancel_work_sync(&hcd->wakeup_work);
2324 #endif
2325 	mutex_lock(&usb_bus_list_lock);
2326 	usb_disconnect(&rhdev);		/* Sets rhdev to NULL */
2327 	mutex_unlock(&usb_bus_list_lock);
2328 err_register_root_hub:
2329 	hcd->rh_pollable = 0;
2330 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2331 	del_timer_sync(&hcd->rh_timer);
2332 	hcd->driver->stop(hcd);
2333 	hcd->state = HC_STATE_HALT;
2334 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2335 	del_timer_sync(&hcd->rh_timer);
2336 err_hcd_driver_start:
2337 	if (hcd->irq >= 0)
2338 		free_irq(irqnum, hcd);
2339 err_request_irq:
2340 err_hcd_driver_setup:
2341 err_set_rh_speed:
2342 	usb_put_dev(hcd->self.root_hub);
2343 err_allocate_root_hub:
2344 	usb_deregister_bus(&hcd->self);
2345 err_register_bus:
2346 	hcd_buffer_destroy(hcd);
2347 	return retval;
2348 }
2349 EXPORT_SYMBOL_GPL(usb_add_hcd);
2350 
2351 /**
2352  * usb_remove_hcd - shutdown processing for generic HCDs
2353  * @hcd: the usb_hcd structure to remove
2354  * Context: !in_interrupt()
2355  *
2356  * Disconnects the root hub, then reverses the effects of usb_add_hcd(),
2357  * invoking the HCD's stop() method.
2358  */
2359 void usb_remove_hcd(struct usb_hcd *hcd)
2360 {
2361 	struct usb_device *rhdev = hcd->self.root_hub;
2362 
2363 	dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);
2364 
2365 	usb_get_dev(rhdev);
2366 	sysfs_remove_group(&rhdev->dev.kobj, &usb_bus_attr_group);
2367 
2368 	if (HC_IS_RUNNING (hcd->state))
2369 		hcd->state = HC_STATE_QUIESCING;
2370 
2371 	dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
2372 	spin_lock_irq (&hcd_root_hub_lock);
2373 	hcd->rh_registered = 0;
2374 	spin_unlock_irq (&hcd_root_hub_lock);
2375 
2376 #ifdef CONFIG_USB_SUSPEND
2377 	cancel_work_sync(&hcd->wakeup_work);
2378 #endif
2379 
2380 	mutex_lock(&usb_bus_list_lock);
2381 	usb_disconnect(&rhdev);		/* Sets rhdev to NULL */
2382 	mutex_unlock(&usb_bus_list_lock);
2383 
2384 	/* Prevent any more root-hub status calls from the timer.
2385 	 * The HCD might still restart the timer (if a port status change
2386 	 * interrupt occurs), but usb_hcd_poll_rh_status() won't invoke
2387 	 * the hub_status_data() callback.
2388 	 */
2389 	hcd->rh_pollable = 0;
2390 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2391 	del_timer_sync(&hcd->rh_timer);
2392 
2393 	hcd->driver->stop(hcd);
2394 	hcd->state = HC_STATE_HALT;
2395 
2396 	/* In case the HCD restarted the timer, stop it again. */
2397 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2398 	del_timer_sync(&hcd->rh_timer);
2399 
2400 	if (hcd->irq >= 0)
2401 		free_irq(hcd->irq, hcd);
2402 
2403 	usb_put_dev(hcd->self.root_hub);
2404 	usb_deregister_bus(&hcd->self);
2405 	hcd_buffer_destroy(hcd);
2406 }
2407 EXPORT_SYMBOL_GPL(usb_remove_hcd);
2408 
2409 void
2410 usb_hcd_platform_shutdown(struct platform_device* dev)
2411 {
2412 	struct usb_hcd *hcd = platform_get_drvdata(dev);
2413 
2414 	if (hcd->driver->shutdown)
2415 		hcd->driver->shutdown(hcd);
2416 }
2417 EXPORT_SYMBOL_GPL(usb_hcd_platform_shutdown);
2418 
2419 /*-------------------------------------------------------------------------*/
2420 
2421 #if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)
2422 
2423 struct usb_mon_operations *mon_ops;
2424 
2425 /*
2426  * The registration is unlocked.
2427  * We do it this way because we do not want to lock in hot paths.
2428  *
2429  * Notice that the code is minimally error-proof. Because usbmon needs
2430  * symbols from usbcore, usbcore gets referenced and cannot be unloaded first.
2431  */
2432 
2433 int usb_mon_register (struct usb_mon_operations *ops)
2434 {
2435 
2436 	if (mon_ops)
2437 		return -EBUSY;
2438 
2439 	mon_ops = ops;
2440 	mb();
2441 	return 0;
2442 }
2443 EXPORT_SYMBOL_GPL (usb_mon_register);
2444 
2445 void usb_mon_deregister (void)
2446 {
2447 
2448 	if (mon_ops == NULL) {
2449 		printk(KERN_ERR "USB: monitor was not registered\n");
2450 		return;
2451 	}
2452 	mon_ops = NULL;
2453 	mb();
2454 }
2455 EXPORT_SYMBOL_GPL (usb_mon_deregister);
2456 
2457 #endif /* CONFIG_USB_MON || CONFIG_USB_MON_MODULE */
2458