xref: /linux/drivers/usb/core/hcd.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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/mutex.h>
42 #include <linux/pm_runtime.h>
43 
44 #include <linux/usb.h>
45 
46 #include "usb.h"
47 #include "hcd.h"
48 #include "hub.h"
49 
50 
51 /*-------------------------------------------------------------------------*/
52 
53 /*
54  * USB Host Controller Driver framework
55  *
56  * Plugs into usbcore (usb_bus) and lets HCDs share code, minimizing
57  * HCD-specific behaviors/bugs.
58  *
59  * This does error checks, tracks devices and urbs, and delegates to a
60  * "hc_driver" only for code (and data) that really needs to know about
61  * hardware differences.  That includes root hub registers, i/o queues,
62  * and so on ... but as little else as possible.
63  *
64  * Shared code includes most of the "root hub" code (these are emulated,
65  * though each HC's hardware works differently) and PCI glue, plus request
66  * tracking overhead.  The HCD code should only block on spinlocks or on
67  * hardware handshaking; blocking on software events (such as other kernel
68  * threads releasing resources, or completing actions) is all generic.
69  *
70  * Happens the USB 2.0 spec says this would be invisible inside the "USBD",
71  * and includes mostly a "HCDI" (HCD Interface) along with some APIs used
72  * only by the hub driver ... and that neither should be seen or used by
73  * usb client device drivers.
74  *
75  * Contributors of ideas or unattributed patches include: David Brownell,
76  * Roman Weissgaerber, Rory Bolt, Greg Kroah-Hartman, ...
77  *
78  * HISTORY:
79  * 2002-02-21	Pull in most of the usb_bus support from usb.c; some
80  *		associated cleanup.  "usb_hcd" still != "usb_bus".
81  * 2001-12-12	Initial patch version for Linux 2.5.1 kernel.
82  */
83 
84 /*-------------------------------------------------------------------------*/
85 
86 /* Keep track of which host controller drivers are loaded */
87 unsigned long usb_hcds_loaded;
88 EXPORT_SYMBOL_GPL(usb_hcds_loaded);
89 
90 /* host controllers we manage */
91 LIST_HEAD (usb_bus_list);
92 EXPORT_SYMBOL_GPL (usb_bus_list);
93 
94 /* used when allocating bus numbers */
95 #define USB_MAXBUS		64
96 struct usb_busmap {
97 	unsigned long busmap [USB_MAXBUS / (8*sizeof (unsigned long))];
98 };
99 static struct usb_busmap busmap;
100 
101 /* used when updating list of hcds */
102 DEFINE_MUTEX(usb_bus_list_lock);	/* exported only for usbfs */
103 EXPORT_SYMBOL_GPL (usb_bus_list_lock);
104 
105 /* used for controlling access to virtual root hubs */
106 static DEFINE_SPINLOCK(hcd_root_hub_lock);
107 
108 /* used when updating an endpoint's URB list */
109 static DEFINE_SPINLOCK(hcd_urb_list_lock);
110 
111 /* used to protect against unlinking URBs after the device is gone */
112 static DEFINE_SPINLOCK(hcd_urb_unlink_lock);
113 
114 /* wait queue for synchronous unlinks */
115 DECLARE_WAIT_QUEUE_HEAD(usb_kill_urb_queue);
116 
117 static inline int is_root_hub(struct usb_device *udev)
118 {
119 	return (udev->parent == NULL);
120 }
121 
122 /*-------------------------------------------------------------------------*/
123 
124 /*
125  * Sharable chunks of root hub code.
126  */
127 
128 /*-------------------------------------------------------------------------*/
129 
130 #define KERNEL_REL	((LINUX_VERSION_CODE >> 16) & 0x0ff)
131 #define KERNEL_VER	((LINUX_VERSION_CODE >> 8) & 0x0ff)
132 
133 /* usb 3.0 root hub device descriptor */
134 static const u8 usb3_rh_dev_descriptor[18] = {
135 	0x12,       /*  __u8  bLength; */
136 	0x01,       /*  __u8  bDescriptorType; Device */
137 	0x00, 0x03, /*  __le16 bcdUSB; v3.0 */
138 
139 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
140 	0x00,	    /*  __u8  bDeviceSubClass; */
141 	0x03,       /*  __u8  bDeviceProtocol; USB 3.0 hub */
142 	0x09,       /*  __u8  bMaxPacketSize0; 2^9 = 512 Bytes */
143 
144 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
145 	0x03, 0x00, /*  __le16 idProduct; device 0x0003 */
146 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
147 
148 	0x03,       /*  __u8  iManufacturer; */
149 	0x02,       /*  __u8  iProduct; */
150 	0x01,       /*  __u8  iSerialNumber; */
151 	0x01        /*  __u8  bNumConfigurations; */
152 };
153 
154 /* usb 2.0 root hub device descriptor */
155 static const u8 usb2_rh_dev_descriptor [18] = {
156 	0x12,       /*  __u8  bLength; */
157 	0x01,       /*  __u8  bDescriptorType; Device */
158 	0x00, 0x02, /*  __le16 bcdUSB; v2.0 */
159 
160 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
161 	0x00,	    /*  __u8  bDeviceSubClass; */
162 	0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
163 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
164 
165 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
166 	0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
167 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
168 
169 	0x03,       /*  __u8  iManufacturer; */
170 	0x02,       /*  __u8  iProduct; */
171 	0x01,       /*  __u8  iSerialNumber; */
172 	0x01        /*  __u8  bNumConfigurations; */
173 };
174 
175 /* no usb 2.0 root hub "device qualifier" descriptor: one speed only */
176 
177 /* usb 1.1 root hub device descriptor */
178 static const u8 usb11_rh_dev_descriptor [18] = {
179 	0x12,       /*  __u8  bLength; */
180 	0x01,       /*  __u8  bDescriptorType; Device */
181 	0x10, 0x01, /*  __le16 bcdUSB; v1.1 */
182 
183 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
184 	0x00,	    /*  __u8  bDeviceSubClass; */
185 	0x00,       /*  __u8  bDeviceProtocol; [ low/full speeds only ] */
186 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
187 
188 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
189 	0x01, 0x00, /*  __le16 idProduct; device 0x0001 */
190 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
191 
192 	0x03,       /*  __u8  iManufacturer; */
193 	0x02,       /*  __u8  iProduct; */
194 	0x01,       /*  __u8  iSerialNumber; */
195 	0x01        /*  __u8  bNumConfigurations; */
196 };
197 
198 
199 /*-------------------------------------------------------------------------*/
200 
201 /* Configuration descriptors for our root hubs */
202 
203 static const u8 fs_rh_config_descriptor [] = {
204 
205 	/* one configuration */
206 	0x09,       /*  __u8  bLength; */
207 	0x02,       /*  __u8  bDescriptorType; Configuration */
208 	0x19, 0x00, /*  __le16 wTotalLength; */
209 	0x01,       /*  __u8  bNumInterfaces; (1) */
210 	0x01,       /*  __u8  bConfigurationValue; */
211 	0x00,       /*  __u8  iConfiguration; */
212 	0xc0,       /*  __u8  bmAttributes;
213 				 Bit 7: must be set,
214 				     6: Self-powered,
215 				     5: Remote wakeup,
216 				     4..0: resvd */
217 	0x00,       /*  __u8  MaxPower; */
218 
219 	/* USB 1.1:
220 	 * USB 2.0, single TT organization (mandatory):
221 	 *	one interface, protocol 0
222 	 *
223 	 * USB 2.0, multiple TT organization (optional):
224 	 *	two interfaces, protocols 1 (like single TT)
225 	 *	and 2 (multiple TT mode) ... config is
226 	 *	sometimes settable
227 	 *	NOT IMPLEMENTED
228 	 */
229 
230 	/* one interface */
231 	0x09,       /*  __u8  if_bLength; */
232 	0x04,       /*  __u8  if_bDescriptorType; Interface */
233 	0x00,       /*  __u8  if_bInterfaceNumber; */
234 	0x00,       /*  __u8  if_bAlternateSetting; */
235 	0x01,       /*  __u8  if_bNumEndpoints; */
236 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
237 	0x00,       /*  __u8  if_bInterfaceSubClass; */
238 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
239 	0x00,       /*  __u8  if_iInterface; */
240 
241 	/* one endpoint (status change endpoint) */
242 	0x07,       /*  __u8  ep_bLength; */
243 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
244 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
245  	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
246  	0x02, 0x00, /*  __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) */
247 	0xff        /*  __u8  ep_bInterval; (255ms -- usb 2.0 spec) */
248 };
249 
250 static const u8 hs_rh_config_descriptor [] = {
251 
252 	/* one configuration */
253 	0x09,       /*  __u8  bLength; */
254 	0x02,       /*  __u8  bDescriptorType; Configuration */
255 	0x19, 0x00, /*  __le16 wTotalLength; */
256 	0x01,       /*  __u8  bNumInterfaces; (1) */
257 	0x01,       /*  __u8  bConfigurationValue; */
258 	0x00,       /*  __u8  iConfiguration; */
259 	0xc0,       /*  __u8  bmAttributes;
260 				 Bit 7: must be set,
261 				     6: Self-powered,
262 				     5: Remote wakeup,
263 				     4..0: resvd */
264 	0x00,       /*  __u8  MaxPower; */
265 
266 	/* USB 1.1:
267 	 * USB 2.0, single TT organization (mandatory):
268 	 *	one interface, protocol 0
269 	 *
270 	 * USB 2.0, multiple TT organization (optional):
271 	 *	two interfaces, protocols 1 (like single TT)
272 	 *	and 2 (multiple TT mode) ... config is
273 	 *	sometimes settable
274 	 *	NOT IMPLEMENTED
275 	 */
276 
277 	/* one interface */
278 	0x09,       /*  __u8  if_bLength; */
279 	0x04,       /*  __u8  if_bDescriptorType; Interface */
280 	0x00,       /*  __u8  if_bInterfaceNumber; */
281 	0x00,       /*  __u8  if_bAlternateSetting; */
282 	0x01,       /*  __u8  if_bNumEndpoints; */
283 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
284 	0x00,       /*  __u8  if_bInterfaceSubClass; */
285 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
286 	0x00,       /*  __u8  if_iInterface; */
287 
288 	/* one endpoint (status change endpoint) */
289 	0x07,       /*  __u8  ep_bLength; */
290 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
291 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
292  	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
293 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
294 		     * see hub.c:hub_configure() for details. */
295 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
296 	0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
297 };
298 
299 static const u8 ss_rh_config_descriptor[] = {
300 	/* one configuration */
301 	0x09,       /*  __u8  bLength; */
302 	0x02,       /*  __u8  bDescriptorType; Configuration */
303 	0x19, 0x00, /*  __le16 wTotalLength; FIXME */
304 	0x01,       /*  __u8  bNumInterfaces; (1) */
305 	0x01,       /*  __u8  bConfigurationValue; */
306 	0x00,       /*  __u8  iConfiguration; */
307 	0xc0,       /*  __u8  bmAttributes;
308 				 Bit 7: must be set,
309 				     6: Self-powered,
310 				     5: Remote wakeup,
311 				     4..0: resvd */
312 	0x00,       /*  __u8  MaxPower; */
313 
314 	/* one interface */
315 	0x09,       /*  __u8  if_bLength; */
316 	0x04,       /*  __u8  if_bDescriptorType; Interface */
317 	0x00,       /*  __u8  if_bInterfaceNumber; */
318 	0x00,       /*  __u8  if_bAlternateSetting; */
319 	0x01,       /*  __u8  if_bNumEndpoints; */
320 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
321 	0x00,       /*  __u8  if_bInterfaceSubClass; */
322 	0x00,       /*  __u8  if_bInterfaceProtocol; */
323 	0x00,       /*  __u8  if_iInterface; */
324 
325 	/* one endpoint (status change endpoint) */
326 	0x07,       /*  __u8  ep_bLength; */
327 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
328 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
329 	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
330 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
331 		     * see hub.c:hub_configure() for details. */
332 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
333 	0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
334 	/*
335 	 * All 3.0 hubs should have an endpoint companion descriptor,
336 	 * but we're ignoring that for now.  FIXME?
337 	 */
338 };
339 
340 /*-------------------------------------------------------------------------*/
341 
342 /**
343  * ascii2desc() - Helper routine for producing UTF-16LE string descriptors
344  * @s: Null-terminated ASCII (actually ISO-8859-1) string
345  * @buf: Buffer for USB string descriptor (header + UTF-16LE)
346  * @len: Length (in bytes; may be odd) of descriptor buffer.
347  *
348  * The return value is the number of bytes filled in: 2 + 2*strlen(s) or
349  * buflen, whichever is less.
350  *
351  * USB String descriptors can contain at most 126 characters; input
352  * strings longer than that are truncated.
353  */
354 static unsigned
355 ascii2desc(char const *s, u8 *buf, unsigned len)
356 {
357 	unsigned n, t = 2 + 2*strlen(s);
358 
359 	if (t > 254)
360 		t = 254;	/* Longest possible UTF string descriptor */
361 	if (len > t)
362 		len = t;
363 
364 	t += USB_DT_STRING << 8;	/* Now t is first 16 bits to store */
365 
366 	n = len;
367 	while (n--) {
368 		*buf++ = t;
369 		if (!n--)
370 			break;
371 		*buf++ = t >> 8;
372 		t = (unsigned char)*s++;
373 	}
374 	return len;
375 }
376 
377 /**
378  * rh_string() - provides string descriptors for root hub
379  * @id: the string ID number (0: langids, 1: serial #, 2: product, 3: vendor)
380  * @hcd: the host controller for this root hub
381  * @data: buffer for output packet
382  * @len: length of the provided buffer
383  *
384  * Produces either a manufacturer, product or serial number string for the
385  * virtual root hub device.
386  * Returns the number of bytes filled in: the length of the descriptor or
387  * of the provided buffer, whichever is less.
388  */
389 static unsigned
390 rh_string(int id, struct usb_hcd const *hcd, u8 *data, unsigned len)
391 {
392 	char buf[100];
393 	char const *s;
394 	static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04};
395 
396 	// language ids
397 	switch (id) {
398 	case 0:
399 		/* Array of LANGID codes (0x0409 is MSFT-speak for "en-us") */
400 		/* See http://www.usb.org/developers/docs/USB_LANGIDs.pdf */
401 		if (len > 4)
402 			len = 4;
403 		memcpy(data, langids, len);
404 		return len;
405 	case 1:
406 		/* Serial number */
407 		s = hcd->self.bus_name;
408 		break;
409 	case 2:
410 		/* Product name */
411 		s = hcd->product_desc;
412 		break;
413 	case 3:
414 		/* Manufacturer */
415 		snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
416 			init_utsname()->release, hcd->driver->description);
417 		s = buf;
418 		break;
419 	default:
420 		/* Can't happen; caller guarantees it */
421 		return 0;
422 	}
423 
424 	return ascii2desc(s, data, len);
425 }
426 
427 
428 /* Root hub control transfers execute synchronously */
429 static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
430 {
431 	struct usb_ctrlrequest *cmd;
432  	u16		typeReq, wValue, wIndex, wLength;
433 	u8		*ubuf = urb->transfer_buffer;
434 	u8		tbuf [sizeof (struct usb_hub_descriptor)]
435 		__attribute__((aligned(4)));
436 	const u8	*bufp = tbuf;
437 	unsigned	len = 0;
438 	int		status;
439 	u8		patch_wakeup = 0;
440 	u8		patch_protocol = 0;
441 
442 	might_sleep();
443 
444 	spin_lock_irq(&hcd_root_hub_lock);
445 	status = usb_hcd_link_urb_to_ep(hcd, urb);
446 	spin_unlock_irq(&hcd_root_hub_lock);
447 	if (status)
448 		return status;
449 	urb->hcpriv = hcd;	/* Indicate it's queued */
450 
451 	cmd = (struct usb_ctrlrequest *) urb->setup_packet;
452 	typeReq  = (cmd->bRequestType << 8) | cmd->bRequest;
453 	wValue   = le16_to_cpu (cmd->wValue);
454 	wIndex   = le16_to_cpu (cmd->wIndex);
455 	wLength  = le16_to_cpu (cmd->wLength);
456 
457 	if (wLength > urb->transfer_buffer_length)
458 		goto error;
459 
460 	urb->actual_length = 0;
461 	switch (typeReq) {
462 
463 	/* DEVICE REQUESTS */
464 
465 	/* The root hub's remote wakeup enable bit is implemented using
466 	 * driver model wakeup flags.  If this system supports wakeup
467 	 * through USB, userspace may change the default "allow wakeup"
468 	 * policy through sysfs or these calls.
469 	 *
470 	 * Most root hubs support wakeup from downstream devices, for
471 	 * runtime power management (disabling USB clocks and reducing
472 	 * VBUS power usage).  However, not all of them do so; silicon,
473 	 * board, and BIOS bugs here are not uncommon, so these can't
474 	 * be treated quite like external hubs.
475 	 *
476 	 * Likewise, not all root hubs will pass wakeup events upstream,
477 	 * to wake up the whole system.  So don't assume root hub and
478 	 * controller capabilities are identical.
479 	 */
480 
481 	case DeviceRequest | USB_REQ_GET_STATUS:
482 		tbuf [0] = (device_may_wakeup(&hcd->self.root_hub->dev)
483 					<< USB_DEVICE_REMOTE_WAKEUP)
484 				| (1 << USB_DEVICE_SELF_POWERED);
485 		tbuf [1] = 0;
486 		len = 2;
487 		break;
488 	case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
489 		if (wValue == USB_DEVICE_REMOTE_WAKEUP)
490 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 0);
491 		else
492 			goto error;
493 		break;
494 	case DeviceOutRequest | USB_REQ_SET_FEATURE:
495 		if (device_can_wakeup(&hcd->self.root_hub->dev)
496 				&& wValue == USB_DEVICE_REMOTE_WAKEUP)
497 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 1);
498 		else
499 			goto error;
500 		break;
501 	case DeviceRequest | USB_REQ_GET_CONFIGURATION:
502 		tbuf [0] = 1;
503 		len = 1;
504 			/* FALLTHROUGH */
505 	case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
506 		break;
507 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
508 		switch (wValue & 0xff00) {
509 		case USB_DT_DEVICE << 8:
510 			switch (hcd->driver->flags & HCD_MASK) {
511 			case HCD_USB3:
512 				bufp = usb3_rh_dev_descriptor;
513 				break;
514 			case HCD_USB2:
515 				bufp = usb2_rh_dev_descriptor;
516 				break;
517 			case HCD_USB11:
518 				bufp = usb11_rh_dev_descriptor;
519 				break;
520 			default:
521 				goto error;
522 			}
523 			len = 18;
524 			if (hcd->has_tt)
525 				patch_protocol = 1;
526 			break;
527 		case USB_DT_CONFIG << 8:
528 			switch (hcd->driver->flags & HCD_MASK) {
529 			case HCD_USB3:
530 				bufp = ss_rh_config_descriptor;
531 				len = sizeof ss_rh_config_descriptor;
532 				break;
533 			case HCD_USB2:
534 				bufp = hs_rh_config_descriptor;
535 				len = sizeof hs_rh_config_descriptor;
536 				break;
537 			case HCD_USB11:
538 				bufp = fs_rh_config_descriptor;
539 				len = sizeof fs_rh_config_descriptor;
540 				break;
541 			default:
542 				goto error;
543 			}
544 			if (device_can_wakeup(&hcd->self.root_hub->dev))
545 				patch_wakeup = 1;
546 			break;
547 		case USB_DT_STRING << 8:
548 			if ((wValue & 0xff) < 4)
549 				urb->actual_length = rh_string(wValue & 0xff,
550 						hcd, ubuf, wLength);
551 			else /* unsupported IDs --> "protocol stall" */
552 				goto error;
553 			break;
554 		default:
555 			goto error;
556 		}
557 		break;
558 	case DeviceRequest | USB_REQ_GET_INTERFACE:
559 		tbuf [0] = 0;
560 		len = 1;
561 			/* FALLTHROUGH */
562 	case DeviceOutRequest | USB_REQ_SET_INTERFACE:
563 		break;
564 	case DeviceOutRequest | USB_REQ_SET_ADDRESS:
565 		// wValue == urb->dev->devaddr
566 		dev_dbg (hcd->self.controller, "root hub device address %d\n",
567 			wValue);
568 		break;
569 
570 	/* INTERFACE REQUESTS (no defined feature/status flags) */
571 
572 	/* ENDPOINT REQUESTS */
573 
574 	case EndpointRequest | USB_REQ_GET_STATUS:
575 		// ENDPOINT_HALT flag
576 		tbuf [0] = 0;
577 		tbuf [1] = 0;
578 		len = 2;
579 			/* FALLTHROUGH */
580 	case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
581 	case EndpointOutRequest | USB_REQ_SET_FEATURE:
582 		dev_dbg (hcd->self.controller, "no endpoint features yet\n");
583 		break;
584 
585 	/* CLASS REQUESTS (and errors) */
586 
587 	default:
588 		/* non-generic request */
589 		switch (typeReq) {
590 		case GetHubStatus:
591 		case GetPortStatus:
592 			len = 4;
593 			break;
594 		case GetHubDescriptor:
595 			len = sizeof (struct usb_hub_descriptor);
596 			break;
597 		}
598 		status = hcd->driver->hub_control (hcd,
599 			typeReq, wValue, wIndex,
600 			tbuf, wLength);
601 		break;
602 error:
603 		/* "protocol stall" on error */
604 		status = -EPIPE;
605 	}
606 
607 	if (status) {
608 		len = 0;
609 		if (status != -EPIPE) {
610 			dev_dbg (hcd->self.controller,
611 				"CTRL: TypeReq=0x%x val=0x%x "
612 				"idx=0x%x len=%d ==> %d\n",
613 				typeReq, wValue, wIndex,
614 				wLength, status);
615 		}
616 	}
617 	if (len) {
618 		if (urb->transfer_buffer_length < len)
619 			len = urb->transfer_buffer_length;
620 		urb->actual_length = len;
621 		// always USB_DIR_IN, toward host
622 		memcpy (ubuf, bufp, len);
623 
624 		/* report whether RH hardware supports remote wakeup */
625 		if (patch_wakeup &&
626 				len > offsetof (struct usb_config_descriptor,
627 						bmAttributes))
628 			((struct usb_config_descriptor *)ubuf)->bmAttributes
629 				|= USB_CONFIG_ATT_WAKEUP;
630 
631 		/* report whether RH hardware has an integrated TT */
632 		if (patch_protocol &&
633 				len > offsetof(struct usb_device_descriptor,
634 						bDeviceProtocol))
635 			((struct usb_device_descriptor *) ubuf)->
636 					bDeviceProtocol = 1;
637 	}
638 
639 	/* any errors get returned through the urb completion */
640 	spin_lock_irq(&hcd_root_hub_lock);
641 	usb_hcd_unlink_urb_from_ep(hcd, urb);
642 
643 	/* This peculiar use of spinlocks echoes what real HC drivers do.
644 	 * Avoiding calls to local_irq_disable/enable makes the code
645 	 * RT-friendly.
646 	 */
647 	spin_unlock(&hcd_root_hub_lock);
648 	usb_hcd_giveback_urb(hcd, urb, status);
649 	spin_lock(&hcd_root_hub_lock);
650 
651 	spin_unlock_irq(&hcd_root_hub_lock);
652 	return 0;
653 }
654 
655 /*-------------------------------------------------------------------------*/
656 
657 /*
658  * Root Hub interrupt transfers are polled using a timer if the
659  * driver requests it; otherwise the driver is responsible for
660  * calling usb_hcd_poll_rh_status() when an event occurs.
661  *
662  * Completions are called in_interrupt(), but they may or may not
663  * be in_irq().
664  */
665 void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
666 {
667 	struct urb	*urb;
668 	int		length;
669 	unsigned long	flags;
670 	char		buffer[6];	/* Any root hubs with > 31 ports? */
671 
672 	if (unlikely(!hcd->rh_registered))
673 		return;
674 	if (!hcd->uses_new_polling && !hcd->status_urb)
675 		return;
676 
677 	length = hcd->driver->hub_status_data(hcd, buffer);
678 	if (length > 0) {
679 
680 		/* try to complete the status urb */
681 		spin_lock_irqsave(&hcd_root_hub_lock, flags);
682 		urb = hcd->status_urb;
683 		if (urb) {
684 			hcd->poll_pending = 0;
685 			hcd->status_urb = NULL;
686 			urb->actual_length = length;
687 			memcpy(urb->transfer_buffer, buffer, length);
688 
689 			usb_hcd_unlink_urb_from_ep(hcd, urb);
690 			spin_unlock(&hcd_root_hub_lock);
691 			usb_hcd_giveback_urb(hcd, urb, 0);
692 			spin_lock(&hcd_root_hub_lock);
693 		} else {
694 			length = 0;
695 			hcd->poll_pending = 1;
696 		}
697 		spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
698 	}
699 
700 	/* The USB 2.0 spec says 256 ms.  This is close enough and won't
701 	 * exceed that limit if HZ is 100. The math is more clunky than
702 	 * maybe expected, this is to make sure that all timers for USB devices
703 	 * fire at the same time to give the CPU a break inbetween */
704 	if (hcd->uses_new_polling ? hcd->poll_rh :
705 			(length == 0 && hcd->status_urb != NULL))
706 		mod_timer (&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
707 }
708 EXPORT_SYMBOL_GPL(usb_hcd_poll_rh_status);
709 
710 /* timer callback */
711 static void rh_timer_func (unsigned long _hcd)
712 {
713 	usb_hcd_poll_rh_status((struct usb_hcd *) _hcd);
714 }
715 
716 /*-------------------------------------------------------------------------*/
717 
718 static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
719 {
720 	int		retval;
721 	unsigned long	flags;
722 	unsigned	len = 1 + (urb->dev->maxchild / 8);
723 
724 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
725 	if (hcd->status_urb || urb->transfer_buffer_length < len) {
726 		dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
727 		retval = -EINVAL;
728 		goto done;
729 	}
730 
731 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
732 	if (retval)
733 		goto done;
734 
735 	hcd->status_urb = urb;
736 	urb->hcpriv = hcd;	/* indicate it's queued */
737 	if (!hcd->uses_new_polling)
738 		mod_timer(&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
739 
740 	/* If a status change has already occurred, report it ASAP */
741 	else if (hcd->poll_pending)
742 		mod_timer(&hcd->rh_timer, jiffies);
743 	retval = 0;
744  done:
745 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
746 	return retval;
747 }
748 
749 static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
750 {
751 	if (usb_endpoint_xfer_int(&urb->ep->desc))
752 		return rh_queue_status (hcd, urb);
753 	if (usb_endpoint_xfer_control(&urb->ep->desc))
754 		return rh_call_control (hcd, urb);
755 	return -EINVAL;
756 }
757 
758 /*-------------------------------------------------------------------------*/
759 
760 /* Unlinks of root-hub control URBs are legal, but they don't do anything
761  * since these URBs always execute synchronously.
762  */
763 static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
764 {
765 	unsigned long	flags;
766 	int		rc;
767 
768 	spin_lock_irqsave(&hcd_root_hub_lock, flags);
769 	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
770 	if (rc)
771 		goto done;
772 
773 	if (usb_endpoint_num(&urb->ep->desc) == 0) {	/* Control URB */
774 		;	/* Do nothing */
775 
776 	} else {				/* Status URB */
777 		if (!hcd->uses_new_polling)
778 			del_timer (&hcd->rh_timer);
779 		if (urb == hcd->status_urb) {
780 			hcd->status_urb = NULL;
781 			usb_hcd_unlink_urb_from_ep(hcd, urb);
782 
783 			spin_unlock(&hcd_root_hub_lock);
784 			usb_hcd_giveback_urb(hcd, urb, status);
785 			spin_lock(&hcd_root_hub_lock);
786 		}
787 	}
788  done:
789 	spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
790 	return rc;
791 }
792 
793 
794 
795 /*
796  * Show & store the current value of authorized_default
797  */
798 static ssize_t usb_host_authorized_default_show(struct device *dev,
799 						struct device_attribute *attr,
800 						char *buf)
801 {
802 	struct usb_device *rh_usb_dev = to_usb_device(dev);
803 	struct usb_bus *usb_bus = rh_usb_dev->bus;
804 	struct usb_hcd *usb_hcd;
805 
806 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
807 		return -ENODEV;
808 	usb_hcd = bus_to_hcd(usb_bus);
809 	return snprintf(buf, PAGE_SIZE, "%u\n", usb_hcd->authorized_default);
810 }
811 
812 static ssize_t usb_host_authorized_default_store(struct device *dev,
813 						 struct device_attribute *attr,
814 						 const char *buf, size_t size)
815 {
816 	ssize_t result;
817 	unsigned val;
818 	struct usb_device *rh_usb_dev = to_usb_device(dev);
819 	struct usb_bus *usb_bus = rh_usb_dev->bus;
820 	struct usb_hcd *usb_hcd;
821 
822 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
823 		return -ENODEV;
824 	usb_hcd = bus_to_hcd(usb_bus);
825 	result = sscanf(buf, "%u\n", &val);
826 	if (result == 1) {
827 		usb_hcd->authorized_default = val? 1 : 0;
828 		result = size;
829 	}
830 	else
831 		result = -EINVAL;
832 	return result;
833 }
834 
835 static DEVICE_ATTR(authorized_default, 0644,
836 	    usb_host_authorized_default_show,
837 	    usb_host_authorized_default_store);
838 
839 
840 /* Group all the USB bus attributes */
841 static struct attribute *usb_bus_attrs[] = {
842 		&dev_attr_authorized_default.attr,
843 		NULL,
844 };
845 
846 static struct attribute_group usb_bus_attr_group = {
847 	.name = NULL,	/* we want them in the same directory */
848 	.attrs = usb_bus_attrs,
849 };
850 
851 
852 
853 /*-------------------------------------------------------------------------*/
854 
855 /**
856  * usb_bus_init - shared initialization code
857  * @bus: the bus structure being initialized
858  *
859  * This code is used to initialize a usb_bus structure, memory for which is
860  * separately managed.
861  */
862 static void usb_bus_init (struct usb_bus *bus)
863 {
864 	memset (&bus->devmap, 0, sizeof(struct usb_devmap));
865 
866 	bus->devnum_next = 1;
867 
868 	bus->root_hub = NULL;
869 	bus->busnum = -1;
870 	bus->bandwidth_allocated = 0;
871 	bus->bandwidth_int_reqs  = 0;
872 	bus->bandwidth_isoc_reqs = 0;
873 
874 	INIT_LIST_HEAD (&bus->bus_list);
875 }
876 
877 /*-------------------------------------------------------------------------*/
878 
879 /**
880  * usb_register_bus - registers the USB host controller with the usb core
881  * @bus: pointer to the bus to register
882  * Context: !in_interrupt()
883  *
884  * Assigns a bus number, and links the controller into usbcore data
885  * structures so that it can be seen by scanning the bus list.
886  */
887 static int usb_register_bus(struct usb_bus *bus)
888 {
889 	int result = -E2BIG;
890 	int busnum;
891 
892 	mutex_lock(&usb_bus_list_lock);
893 	busnum = find_next_zero_bit (busmap.busmap, USB_MAXBUS, 1);
894 	if (busnum >= USB_MAXBUS) {
895 		printk (KERN_ERR "%s: too many buses\n", usbcore_name);
896 		goto error_find_busnum;
897 	}
898 	set_bit (busnum, busmap.busmap);
899 	bus->busnum = busnum;
900 
901 	/* Add it to the local list of buses */
902 	list_add (&bus->bus_list, &usb_bus_list);
903 	mutex_unlock(&usb_bus_list_lock);
904 
905 	usb_notify_add_bus(bus);
906 
907 	dev_info (bus->controller, "new USB bus registered, assigned bus "
908 		  "number %d\n", bus->busnum);
909 	return 0;
910 
911 error_find_busnum:
912 	mutex_unlock(&usb_bus_list_lock);
913 	return result;
914 }
915 
916 /**
917  * usb_deregister_bus - deregisters the USB host controller
918  * @bus: pointer to the bus to deregister
919  * Context: !in_interrupt()
920  *
921  * Recycles the bus number, and unlinks the controller from usbcore data
922  * structures so that it won't be seen by scanning the bus list.
923  */
924 static void usb_deregister_bus (struct usb_bus *bus)
925 {
926 	dev_info (bus->controller, "USB bus %d deregistered\n", bus->busnum);
927 
928 	/*
929 	 * NOTE: make sure that all the devices are removed by the
930 	 * controller code, as well as having it call this when cleaning
931 	 * itself up
932 	 */
933 	mutex_lock(&usb_bus_list_lock);
934 	list_del (&bus->bus_list);
935 	mutex_unlock(&usb_bus_list_lock);
936 
937 	usb_notify_remove_bus(bus);
938 
939 	clear_bit (bus->busnum, busmap.busmap);
940 }
941 
942 /**
943  * register_root_hub - called by usb_add_hcd() to register a root hub
944  * @hcd: host controller for this root hub
945  *
946  * This function registers the root hub with the USB subsystem.  It sets up
947  * the device properly in the device tree and then calls usb_new_device()
948  * to register the usb device.  It also assigns the root hub's USB address
949  * (always 1).
950  */
951 static int register_root_hub(struct usb_hcd *hcd)
952 {
953 	struct device *parent_dev = hcd->self.controller;
954 	struct usb_device *usb_dev = hcd->self.root_hub;
955 	const int devnum = 1;
956 	int retval;
957 
958 	usb_dev->devnum = devnum;
959 	usb_dev->bus->devnum_next = devnum + 1;
960 	memset (&usb_dev->bus->devmap.devicemap, 0,
961 			sizeof usb_dev->bus->devmap.devicemap);
962 	set_bit (devnum, usb_dev->bus->devmap.devicemap);
963 	usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
964 
965 	mutex_lock(&usb_bus_list_lock);
966 
967 	usb_dev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
968 	retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE);
969 	if (retval != sizeof usb_dev->descriptor) {
970 		mutex_unlock(&usb_bus_list_lock);
971 		dev_dbg (parent_dev, "can't read %s device descriptor %d\n",
972 				dev_name(&usb_dev->dev), retval);
973 		return (retval < 0) ? retval : -EMSGSIZE;
974 	}
975 
976 	retval = usb_new_device (usb_dev);
977 	if (retval) {
978 		dev_err (parent_dev, "can't register root hub for %s, %d\n",
979 				dev_name(&usb_dev->dev), retval);
980 	}
981 	mutex_unlock(&usb_bus_list_lock);
982 
983 	if (retval == 0) {
984 		spin_lock_irq (&hcd_root_hub_lock);
985 		hcd->rh_registered = 1;
986 		spin_unlock_irq (&hcd_root_hub_lock);
987 
988 		/* Did the HC die before the root hub was registered? */
989 		if (hcd->state == HC_STATE_HALT)
990 			usb_hc_died (hcd);	/* This time clean up */
991 	}
992 
993 	return retval;
994 }
995 
996 
997 /*-------------------------------------------------------------------------*/
998 
999 /**
1000  * usb_calc_bus_time - approximate periodic transaction time in nanoseconds
1001  * @speed: from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
1002  * @is_input: true iff the transaction sends data to the host
1003  * @isoc: true for isochronous transactions, false for interrupt ones
1004  * @bytecount: how many bytes in the transaction.
1005  *
1006  * Returns approximate bus time in nanoseconds for a periodic transaction.
1007  * See USB 2.0 spec section 5.11.3; only periodic transfers need to be
1008  * scheduled in software, this function is only used for such scheduling.
1009  */
1010 long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount)
1011 {
1012 	unsigned long	tmp;
1013 
1014 	switch (speed) {
1015 	case USB_SPEED_LOW: 	/* INTR only */
1016 		if (is_input) {
1017 			tmp = (67667L * (31L + 10L * BitTime (bytecount))) / 1000L;
1018 			return (64060L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
1019 		} else {
1020 			tmp = (66700L * (31L + 10L * BitTime (bytecount))) / 1000L;
1021 			return (64107L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
1022 		}
1023 	case USB_SPEED_FULL:	/* ISOC or INTR */
1024 		if (isoc) {
1025 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1026 			return (((is_input) ? 7268L : 6265L) + BW_HOST_DELAY + tmp);
1027 		} else {
1028 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1029 			return (9107L + BW_HOST_DELAY + tmp);
1030 		}
1031 	case USB_SPEED_HIGH:	/* ISOC or INTR */
1032 		// FIXME adjust for input vs output
1033 		if (isoc)
1034 			tmp = HS_NSECS_ISO (bytecount);
1035 		else
1036 			tmp = HS_NSECS (bytecount);
1037 		return tmp;
1038 	default:
1039 		pr_debug ("%s: bogus device speed!\n", usbcore_name);
1040 		return -1;
1041 	}
1042 }
1043 EXPORT_SYMBOL_GPL(usb_calc_bus_time);
1044 
1045 
1046 /*-------------------------------------------------------------------------*/
1047 
1048 /*
1049  * Generic HC operations.
1050  */
1051 
1052 /*-------------------------------------------------------------------------*/
1053 
1054 /**
1055  * usb_hcd_link_urb_to_ep - add an URB to its endpoint queue
1056  * @hcd: host controller to which @urb was submitted
1057  * @urb: URB being submitted
1058  *
1059  * Host controller drivers should call this routine in their enqueue()
1060  * method.  The HCD's private spinlock must be held and interrupts must
1061  * be disabled.  The actions carried out here are required for URB
1062  * submission, as well as for endpoint shutdown and for usb_kill_urb.
1063  *
1064  * Returns 0 for no error, otherwise a negative error code (in which case
1065  * the enqueue() method must fail).  If no error occurs but enqueue() fails
1066  * anyway, it must call usb_hcd_unlink_urb_from_ep() before releasing
1067  * the private spinlock and returning.
1068  */
1069 int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
1070 {
1071 	int		rc = 0;
1072 
1073 	spin_lock(&hcd_urb_list_lock);
1074 
1075 	/* Check that the URB isn't being killed */
1076 	if (unlikely(atomic_read(&urb->reject))) {
1077 		rc = -EPERM;
1078 		goto done;
1079 	}
1080 
1081 	if (unlikely(!urb->ep->enabled)) {
1082 		rc = -ENOENT;
1083 		goto done;
1084 	}
1085 
1086 	if (unlikely(!urb->dev->can_submit)) {
1087 		rc = -EHOSTUNREACH;
1088 		goto done;
1089 	}
1090 
1091 	/*
1092 	 * Check the host controller's state and add the URB to the
1093 	 * endpoint's queue.
1094 	 */
1095 	switch (hcd->state) {
1096 	case HC_STATE_RUNNING:
1097 	case HC_STATE_RESUMING:
1098 		urb->unlinked = 0;
1099 		list_add_tail(&urb->urb_list, &urb->ep->urb_list);
1100 		break;
1101 	default:
1102 		rc = -ESHUTDOWN;
1103 		goto done;
1104 	}
1105  done:
1106 	spin_unlock(&hcd_urb_list_lock);
1107 	return rc;
1108 }
1109 EXPORT_SYMBOL_GPL(usb_hcd_link_urb_to_ep);
1110 
1111 /**
1112  * usb_hcd_check_unlink_urb - check whether an URB may be unlinked
1113  * @hcd: host controller to which @urb was submitted
1114  * @urb: URB being checked for unlinkability
1115  * @status: error code to store in @urb if the unlink succeeds
1116  *
1117  * Host controller drivers should call this routine in their dequeue()
1118  * method.  The HCD's private spinlock must be held and interrupts must
1119  * be disabled.  The actions carried out here are required for making
1120  * sure than an unlink is valid.
1121  *
1122  * Returns 0 for no error, otherwise a negative error code (in which case
1123  * the dequeue() method must fail).  The possible error codes are:
1124  *
1125  *	-EIDRM: @urb was not submitted or has already completed.
1126  *		The completion function may not have been called yet.
1127  *
1128  *	-EBUSY: @urb has already been unlinked.
1129  */
1130 int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,
1131 		int status)
1132 {
1133 	struct list_head	*tmp;
1134 
1135 	/* insist the urb is still queued */
1136 	list_for_each(tmp, &urb->ep->urb_list) {
1137 		if (tmp == &urb->urb_list)
1138 			break;
1139 	}
1140 	if (tmp != &urb->urb_list)
1141 		return -EIDRM;
1142 
1143 	/* Any status except -EINPROGRESS means something already started to
1144 	 * unlink this URB from the hardware.  So there's no more work to do.
1145 	 */
1146 	if (urb->unlinked)
1147 		return -EBUSY;
1148 	urb->unlinked = status;
1149 
1150 	/* IRQ setup can easily be broken so that USB controllers
1151 	 * never get completion IRQs ... maybe even the ones we need to
1152 	 * finish unlinking the initial failed usb_set_address()
1153 	 * or device descriptor fetch.
1154 	 */
1155 	if (!test_bit(HCD_FLAG_SAW_IRQ, &hcd->flags) &&
1156 			!is_root_hub(urb->dev)) {
1157 		dev_warn(hcd->self.controller, "Unlink after no-IRQ?  "
1158 			"Controller is probably using the wrong IRQ.\n");
1159 		set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
1160 	}
1161 
1162 	return 0;
1163 }
1164 EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb);
1165 
1166 /**
1167  * usb_hcd_unlink_urb_from_ep - remove an URB from its endpoint queue
1168  * @hcd: host controller to which @urb was submitted
1169  * @urb: URB being unlinked
1170  *
1171  * Host controller drivers should call this routine before calling
1172  * usb_hcd_giveback_urb().  The HCD's private spinlock must be held and
1173  * interrupts must be disabled.  The actions carried out here are required
1174  * for URB completion.
1175  */
1176 void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
1177 {
1178 	/* clear all state linking urb to this dev (and hcd) */
1179 	spin_lock(&hcd_urb_list_lock);
1180 	list_del_init(&urb->urb_list);
1181 	spin_unlock(&hcd_urb_list_lock);
1182 }
1183 EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);
1184 
1185 /*
1186  * Some usb host controllers can only perform dma using a small SRAM area.
1187  * The usb core itself is however optimized for host controllers that can dma
1188  * using regular system memory - like pci devices doing bus mastering.
1189  *
1190  * To support host controllers with limited dma capabilites we provide dma
1191  * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag.
1192  * For this to work properly the host controller code must first use the
1193  * function dma_declare_coherent_memory() to point out which memory area
1194  * that should be used for dma allocations.
1195  *
1196  * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for
1197  * dma using dma_alloc_coherent() which in turn allocates from the memory
1198  * area pointed out with dma_declare_coherent_memory().
1199  *
1200  * So, to summarize...
1201  *
1202  * - We need "local" memory, canonical example being
1203  *   a small SRAM on a discrete controller being the
1204  *   only memory that the controller can read ...
1205  *   (a) "normal" kernel memory is no good, and
1206  *   (b) there's not enough to share
1207  *
1208  * - The only *portable* hook for such stuff in the
1209  *   DMA framework is dma_declare_coherent_memory()
1210  *
1211  * - So we use that, even though the primary requirement
1212  *   is that the memory be "local" (hence addressible
1213  *   by that device), not "coherent".
1214  *
1215  */
1216 
1217 static int hcd_alloc_coherent(struct usb_bus *bus,
1218 			      gfp_t mem_flags, dma_addr_t *dma_handle,
1219 			      void **vaddr_handle, size_t size,
1220 			      enum dma_data_direction dir)
1221 {
1222 	unsigned char *vaddr;
1223 
1224 	vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
1225 				 mem_flags, dma_handle);
1226 	if (!vaddr)
1227 		return -ENOMEM;
1228 
1229 	/*
1230 	 * Store the virtual address of the buffer at the end
1231 	 * of the allocated dma buffer. The size of the buffer
1232 	 * may be uneven so use unaligned functions instead
1233 	 * of just rounding up. It makes sense to optimize for
1234 	 * memory footprint over access speed since the amount
1235 	 * of memory available for dma may be limited.
1236 	 */
1237 	put_unaligned((unsigned long)*vaddr_handle,
1238 		      (unsigned long *)(vaddr + size));
1239 
1240 	if (dir == DMA_TO_DEVICE)
1241 		memcpy(vaddr, *vaddr_handle, size);
1242 
1243 	*vaddr_handle = vaddr;
1244 	return 0;
1245 }
1246 
1247 static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
1248 			      void **vaddr_handle, size_t size,
1249 			      enum dma_data_direction dir)
1250 {
1251 	unsigned char *vaddr = *vaddr_handle;
1252 
1253 	vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size));
1254 
1255 	if (dir == DMA_FROM_DEVICE)
1256 		memcpy(vaddr, *vaddr_handle, size);
1257 
1258 	hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle);
1259 
1260 	*vaddr_handle = vaddr;
1261 	*dma_handle = 0;
1262 }
1263 
1264 static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
1265 			   gfp_t mem_flags)
1266 {
1267 	enum dma_data_direction dir;
1268 	int ret = 0;
1269 
1270 	/* Map the URB's buffers for DMA access.
1271 	 * Lower level HCD code should use *_dma exclusively,
1272 	 * unless it uses pio or talks to another transport,
1273 	 * or uses the provided scatter gather list for bulk.
1274 	 */
1275 	if (is_root_hub(urb->dev))
1276 		return 0;
1277 
1278 	if (usb_endpoint_xfer_control(&urb->ep->desc)
1279 	    && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
1280 		if (hcd->self.uses_dma) {
1281 			urb->setup_dma = dma_map_single(
1282 					hcd->self.controller,
1283 					urb->setup_packet,
1284 					sizeof(struct usb_ctrlrequest),
1285 					DMA_TO_DEVICE);
1286 			if (dma_mapping_error(hcd->self.controller,
1287 						urb->setup_dma))
1288 				return -EAGAIN;
1289 		} else if (hcd->driver->flags & HCD_LOCAL_MEM)
1290 			ret = hcd_alloc_coherent(
1291 					urb->dev->bus, mem_flags,
1292 					&urb->setup_dma,
1293 					(void **)&urb->setup_packet,
1294 					sizeof(struct usb_ctrlrequest),
1295 					DMA_TO_DEVICE);
1296 	}
1297 
1298 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1299 	if (ret == 0 && urb->transfer_buffer_length != 0
1300 	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
1301 		if (hcd->self.uses_dma) {
1302 			urb->transfer_dma = dma_map_single (
1303 					hcd->self.controller,
1304 					urb->transfer_buffer,
1305 					urb->transfer_buffer_length,
1306 					dir);
1307 			if (dma_mapping_error(hcd->self.controller,
1308 						urb->transfer_dma))
1309 				return -EAGAIN;
1310 		} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
1311 			ret = hcd_alloc_coherent(
1312 					urb->dev->bus, mem_flags,
1313 					&urb->transfer_dma,
1314 					&urb->transfer_buffer,
1315 					urb->transfer_buffer_length,
1316 					dir);
1317 
1318 			if (ret && usb_endpoint_xfer_control(&urb->ep->desc)
1319 			    && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
1320 				hcd_free_coherent(urb->dev->bus,
1321 					&urb->setup_dma,
1322 					(void **)&urb->setup_packet,
1323 					sizeof(struct usb_ctrlrequest),
1324 					DMA_TO_DEVICE);
1325 		}
1326 	}
1327 	return ret;
1328 }
1329 
1330 static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
1331 {
1332 	enum dma_data_direction dir;
1333 
1334 	if (is_root_hub(urb->dev))
1335 		return;
1336 
1337 	if (usb_endpoint_xfer_control(&urb->ep->desc)
1338 	    && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
1339 		if (hcd->self.uses_dma)
1340 			dma_unmap_single(hcd->self.controller, urb->setup_dma,
1341 					sizeof(struct usb_ctrlrequest),
1342 					DMA_TO_DEVICE);
1343 		else if (hcd->driver->flags & HCD_LOCAL_MEM)
1344 			hcd_free_coherent(urb->dev->bus, &urb->setup_dma,
1345 					(void **)&urb->setup_packet,
1346 					sizeof(struct usb_ctrlrequest),
1347 					DMA_TO_DEVICE);
1348 	}
1349 
1350 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1351 	if (urb->transfer_buffer_length != 0
1352 	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
1353 		if (hcd->self.uses_dma)
1354 			dma_unmap_single(hcd->self.controller,
1355 					urb->transfer_dma,
1356 					urb->transfer_buffer_length,
1357 					dir);
1358 		else if (hcd->driver->flags & HCD_LOCAL_MEM)
1359 			hcd_free_coherent(urb->dev->bus, &urb->transfer_dma,
1360 					&urb->transfer_buffer,
1361 					urb->transfer_buffer_length,
1362 					dir);
1363 	}
1364 }
1365 
1366 /*-------------------------------------------------------------------------*/
1367 
1368 /* may be called in any context with a valid urb->dev usecount
1369  * caller surrenders "ownership" of urb
1370  * expects usb_submit_urb() to have sanity checked and conditioned all
1371  * inputs in the urb
1372  */
1373 int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
1374 {
1375 	int			status;
1376 	struct usb_hcd		*hcd = bus_to_hcd(urb->dev->bus);
1377 
1378 	/* increment urb's reference count as part of giving it to the HCD
1379 	 * (which will control it).  HCD guarantees that it either returns
1380 	 * an error or calls giveback(), but not both.
1381 	 */
1382 	usb_get_urb(urb);
1383 	atomic_inc(&urb->use_count);
1384 	atomic_inc(&urb->dev->urbnum);
1385 	usbmon_urb_submit(&hcd->self, urb);
1386 
1387 	/* NOTE requirements on root-hub callers (usbfs and the hub
1388 	 * driver, for now):  URBs' urb->transfer_buffer must be
1389 	 * valid and usb_buffer_{sync,unmap}() not be needed, since
1390 	 * they could clobber root hub response data.  Also, control
1391 	 * URBs must be submitted in process context with interrupts
1392 	 * enabled.
1393 	 */
1394 	status = map_urb_for_dma(hcd, urb, mem_flags);
1395 	if (unlikely(status)) {
1396 		usbmon_urb_submit_error(&hcd->self, urb, status);
1397 		goto error;
1398 	}
1399 
1400 	if (is_root_hub(urb->dev))
1401 		status = rh_urb_enqueue(hcd, urb);
1402 	else
1403 		status = hcd->driver->urb_enqueue(hcd, urb, mem_flags);
1404 
1405 	if (unlikely(status)) {
1406 		usbmon_urb_submit_error(&hcd->self, urb, status);
1407 		unmap_urb_for_dma(hcd, urb);
1408  error:
1409 		urb->hcpriv = NULL;
1410 		INIT_LIST_HEAD(&urb->urb_list);
1411 		atomic_dec(&urb->use_count);
1412 		atomic_dec(&urb->dev->urbnum);
1413 		if (atomic_read(&urb->reject))
1414 			wake_up(&usb_kill_urb_queue);
1415 		usb_put_urb(urb);
1416 	}
1417 	return status;
1418 }
1419 
1420 /*-------------------------------------------------------------------------*/
1421 
1422 /* this makes the hcd giveback() the urb more quickly, by kicking it
1423  * off hardware queues (which may take a while) and returning it as
1424  * soon as practical.  we've already set up the urb's return status,
1425  * but we can't know if the callback completed already.
1426  */
1427 static int unlink1(struct usb_hcd *hcd, struct urb *urb, int status)
1428 {
1429 	int		value;
1430 
1431 	if (is_root_hub(urb->dev))
1432 		value = usb_rh_urb_dequeue(hcd, urb, status);
1433 	else {
1434 
1435 		/* The only reason an HCD might fail this call is if
1436 		 * it has not yet fully queued the urb to begin with.
1437 		 * Such failures should be harmless. */
1438 		value = hcd->driver->urb_dequeue(hcd, urb, status);
1439 	}
1440 	return value;
1441 }
1442 
1443 /*
1444  * called in any context
1445  *
1446  * caller guarantees urb won't be recycled till both unlink()
1447  * and the urb's completion function return
1448  */
1449 int usb_hcd_unlink_urb (struct urb *urb, int status)
1450 {
1451 	struct usb_hcd		*hcd;
1452 	int			retval = -EIDRM;
1453 	unsigned long		flags;
1454 
1455 	/* Prevent the device and bus from going away while
1456 	 * the unlink is carried out.  If they are already gone
1457 	 * then urb->use_count must be 0, since disconnected
1458 	 * devices can't have any active URBs.
1459 	 */
1460 	spin_lock_irqsave(&hcd_urb_unlink_lock, flags);
1461 	if (atomic_read(&urb->use_count) > 0) {
1462 		retval = 0;
1463 		usb_get_dev(urb->dev);
1464 	}
1465 	spin_unlock_irqrestore(&hcd_urb_unlink_lock, flags);
1466 	if (retval == 0) {
1467 		hcd = bus_to_hcd(urb->dev->bus);
1468 		retval = unlink1(hcd, urb, status);
1469 		usb_put_dev(urb->dev);
1470 	}
1471 
1472 	if (retval == 0)
1473 		retval = -EINPROGRESS;
1474 	else if (retval != -EIDRM && retval != -EBUSY)
1475 		dev_dbg(&urb->dev->dev, "hcd_unlink_urb %p fail %d\n",
1476 				urb, retval);
1477 	return retval;
1478 }
1479 
1480 /*-------------------------------------------------------------------------*/
1481 
1482 /**
1483  * usb_hcd_giveback_urb - return URB from HCD to device driver
1484  * @hcd: host controller returning the URB
1485  * @urb: urb being returned to the USB device driver.
1486  * @status: completion status code for the URB.
1487  * Context: in_interrupt()
1488  *
1489  * This hands the URB from HCD to its USB device driver, using its
1490  * completion function.  The HCD has freed all per-urb resources
1491  * (and is done using urb->hcpriv).  It also released all HCD locks;
1492  * the device driver won't cause problems if it frees, modifies,
1493  * or resubmits this URB.
1494  *
1495  * If @urb was unlinked, the value of @status will be overridden by
1496  * @urb->unlinked.  Erroneous short transfers are detected in case
1497  * the HCD hasn't checked for them.
1498  */
1499 void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
1500 {
1501 	urb->hcpriv = NULL;
1502 	if (unlikely(urb->unlinked))
1503 		status = urb->unlinked;
1504 	else if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
1505 			urb->actual_length < urb->transfer_buffer_length &&
1506 			!status))
1507 		status = -EREMOTEIO;
1508 
1509 	unmap_urb_for_dma(hcd, urb);
1510 	usbmon_urb_complete(&hcd->self, urb, status);
1511 	usb_unanchor_urb(urb);
1512 
1513 	/* pass ownership to the completion handler */
1514 	urb->status = status;
1515 	urb->complete (urb);
1516 	atomic_dec (&urb->use_count);
1517 	if (unlikely(atomic_read(&urb->reject)))
1518 		wake_up (&usb_kill_urb_queue);
1519 	usb_put_urb (urb);
1520 }
1521 EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb);
1522 
1523 /*-------------------------------------------------------------------------*/
1524 
1525 /* Cancel all URBs pending on this endpoint and wait for the endpoint's
1526  * queue to drain completely.  The caller must first insure that no more
1527  * URBs can be submitted for this endpoint.
1528  */
1529 void usb_hcd_flush_endpoint(struct usb_device *udev,
1530 		struct usb_host_endpoint *ep)
1531 {
1532 	struct usb_hcd		*hcd;
1533 	struct urb		*urb;
1534 
1535 	if (!ep)
1536 		return;
1537 	might_sleep();
1538 	hcd = bus_to_hcd(udev->bus);
1539 
1540 	/* No more submits can occur */
1541 	spin_lock_irq(&hcd_urb_list_lock);
1542 rescan:
1543 	list_for_each_entry (urb, &ep->urb_list, urb_list) {
1544 		int	is_in;
1545 
1546 		if (urb->unlinked)
1547 			continue;
1548 		usb_get_urb (urb);
1549 		is_in = usb_urb_dir_in(urb);
1550 		spin_unlock(&hcd_urb_list_lock);
1551 
1552 		/* kick hcd */
1553 		unlink1(hcd, urb, -ESHUTDOWN);
1554 		dev_dbg (hcd->self.controller,
1555 			"shutdown urb %p ep%d%s%s\n",
1556 			urb, usb_endpoint_num(&ep->desc),
1557 			is_in ? "in" : "out",
1558 			({	char *s;
1559 
1560 				 switch (usb_endpoint_type(&ep->desc)) {
1561 				 case USB_ENDPOINT_XFER_CONTROL:
1562 					s = ""; break;
1563 				 case USB_ENDPOINT_XFER_BULK:
1564 					s = "-bulk"; break;
1565 				 case USB_ENDPOINT_XFER_INT:
1566 					s = "-intr"; break;
1567 				 default:
1568 			 		s = "-iso"; break;
1569 				};
1570 				s;
1571 			}));
1572 		usb_put_urb (urb);
1573 
1574 		/* list contents may have changed */
1575 		spin_lock(&hcd_urb_list_lock);
1576 		goto rescan;
1577 	}
1578 	spin_unlock_irq(&hcd_urb_list_lock);
1579 
1580 	/* Wait until the endpoint queue is completely empty */
1581 	while (!list_empty (&ep->urb_list)) {
1582 		spin_lock_irq(&hcd_urb_list_lock);
1583 
1584 		/* The list may have changed while we acquired the spinlock */
1585 		urb = NULL;
1586 		if (!list_empty (&ep->urb_list)) {
1587 			urb = list_entry (ep->urb_list.prev, struct urb,
1588 					urb_list);
1589 			usb_get_urb (urb);
1590 		}
1591 		spin_unlock_irq(&hcd_urb_list_lock);
1592 
1593 		if (urb) {
1594 			usb_kill_urb (urb);
1595 			usb_put_urb (urb);
1596 		}
1597 	}
1598 }
1599 
1600 /**
1601  * usb_hcd_alloc_bandwidth - check whether a new bandwidth setting exceeds
1602  *				the bus bandwidth
1603  * @udev: target &usb_device
1604  * @new_config: new configuration to install
1605  * @cur_alt: the current alternate interface setting
1606  * @new_alt: alternate interface setting that is being installed
1607  *
1608  * To change configurations, pass in the new configuration in new_config,
1609  * and pass NULL for cur_alt and new_alt.
1610  *
1611  * To reset a device's configuration (put the device in the ADDRESSED state),
1612  * pass in NULL for new_config, cur_alt, and new_alt.
1613  *
1614  * To change alternate interface settings, pass in NULL for new_config,
1615  * pass in the current alternate interface setting in cur_alt,
1616  * and pass in the new alternate interface setting in new_alt.
1617  *
1618  * Returns an error if the requested bandwidth change exceeds the
1619  * bus bandwidth or host controller internal resources.
1620  */
1621 int usb_hcd_alloc_bandwidth(struct usb_device *udev,
1622 		struct usb_host_config *new_config,
1623 		struct usb_host_interface *cur_alt,
1624 		struct usb_host_interface *new_alt)
1625 {
1626 	int num_intfs, i, j;
1627 	struct usb_host_interface *alt = NULL;
1628 	int ret = 0;
1629 	struct usb_hcd *hcd;
1630 	struct usb_host_endpoint *ep;
1631 
1632 	hcd = bus_to_hcd(udev->bus);
1633 	if (!hcd->driver->check_bandwidth)
1634 		return 0;
1635 
1636 	/* Configuration is being removed - set configuration 0 */
1637 	if (!new_config && !cur_alt) {
1638 		for (i = 1; i < 16; ++i) {
1639 			ep = udev->ep_out[i];
1640 			if (ep)
1641 				hcd->driver->drop_endpoint(hcd, udev, ep);
1642 			ep = udev->ep_in[i];
1643 			if (ep)
1644 				hcd->driver->drop_endpoint(hcd, udev, ep);
1645 		}
1646 		hcd->driver->check_bandwidth(hcd, udev);
1647 		return 0;
1648 	}
1649 	/* Check if the HCD says there's enough bandwidth.  Enable all endpoints
1650 	 * each interface's alt setting 0 and ask the HCD to check the bandwidth
1651 	 * of the bus.  There will always be bandwidth for endpoint 0, so it's
1652 	 * ok to exclude it.
1653 	 */
1654 	if (new_config) {
1655 		num_intfs = new_config->desc.bNumInterfaces;
1656 		/* Remove endpoints (except endpoint 0, which is always on the
1657 		 * schedule) from the old config from the schedule
1658 		 */
1659 		for (i = 1; i < 16; ++i) {
1660 			ep = udev->ep_out[i];
1661 			if (ep) {
1662 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1663 				if (ret < 0)
1664 					goto reset;
1665 			}
1666 			ep = udev->ep_in[i];
1667 			if (ep) {
1668 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1669 				if (ret < 0)
1670 					goto reset;
1671 			}
1672 		}
1673 		for (i = 0; i < num_intfs; ++i) {
1674 			struct usb_host_interface *first_alt;
1675 			int iface_num;
1676 
1677 			first_alt = &new_config->intf_cache[i]->altsetting[0];
1678 			iface_num = first_alt->desc.bInterfaceNumber;
1679 			/* Set up endpoints for alternate interface setting 0 */
1680 			alt = usb_find_alt_setting(new_config, iface_num, 0);
1681 			if (!alt)
1682 				/* No alt setting 0? Pick the first setting. */
1683 				alt = first_alt;
1684 
1685 			for (j = 0; j < alt->desc.bNumEndpoints; j++) {
1686 				ret = hcd->driver->add_endpoint(hcd, udev, &alt->endpoint[j]);
1687 				if (ret < 0)
1688 					goto reset;
1689 			}
1690 		}
1691 	}
1692 	if (cur_alt && new_alt) {
1693 		struct usb_interface *iface = usb_ifnum_to_if(udev,
1694 				cur_alt->desc.bInterfaceNumber);
1695 
1696 		if (iface->resetting_device) {
1697 			/*
1698 			 * The USB core just reset the device, so the xHCI host
1699 			 * and the device will think alt setting 0 is installed.
1700 			 * However, the USB core will pass in the alternate
1701 			 * setting installed before the reset as cur_alt.  Dig
1702 			 * out the alternate setting 0 structure, or the first
1703 			 * alternate setting if a broken device doesn't have alt
1704 			 * setting 0.
1705 			 */
1706 			cur_alt = usb_altnum_to_altsetting(iface, 0);
1707 			if (!cur_alt)
1708 				cur_alt = &iface->altsetting[0];
1709 		}
1710 
1711 		/* Drop all the endpoints in the current alt setting */
1712 		for (i = 0; i < cur_alt->desc.bNumEndpoints; i++) {
1713 			ret = hcd->driver->drop_endpoint(hcd, udev,
1714 					&cur_alt->endpoint[i]);
1715 			if (ret < 0)
1716 				goto reset;
1717 		}
1718 		/* Add all the endpoints in the new alt setting */
1719 		for (i = 0; i < new_alt->desc.bNumEndpoints; i++) {
1720 			ret = hcd->driver->add_endpoint(hcd, udev,
1721 					&new_alt->endpoint[i]);
1722 			if (ret < 0)
1723 				goto reset;
1724 		}
1725 	}
1726 	ret = hcd->driver->check_bandwidth(hcd, udev);
1727 reset:
1728 	if (ret < 0)
1729 		hcd->driver->reset_bandwidth(hcd, udev);
1730 	return ret;
1731 }
1732 
1733 /* Disables the endpoint: synchronizes with the hcd to make sure all
1734  * endpoint state is gone from hardware.  usb_hcd_flush_endpoint() must
1735  * have been called previously.  Use for set_configuration, set_interface,
1736  * driver removal, physical disconnect.
1737  *
1738  * example:  a qh stored in ep->hcpriv, holding state related to endpoint
1739  * type, maxpacket size, toggle, halt status, and scheduling.
1740  */
1741 void usb_hcd_disable_endpoint(struct usb_device *udev,
1742 		struct usb_host_endpoint *ep)
1743 {
1744 	struct usb_hcd		*hcd;
1745 
1746 	might_sleep();
1747 	hcd = bus_to_hcd(udev->bus);
1748 	if (hcd->driver->endpoint_disable)
1749 		hcd->driver->endpoint_disable(hcd, ep);
1750 }
1751 
1752 /**
1753  * usb_hcd_reset_endpoint - reset host endpoint state
1754  * @udev: USB device.
1755  * @ep:   the endpoint to reset.
1756  *
1757  * Resets any host endpoint state such as the toggle bit, sequence
1758  * number and current window.
1759  */
1760 void usb_hcd_reset_endpoint(struct usb_device *udev,
1761 			    struct usb_host_endpoint *ep)
1762 {
1763 	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
1764 
1765 	if (hcd->driver->endpoint_reset)
1766 		hcd->driver->endpoint_reset(hcd, ep);
1767 	else {
1768 		int epnum = usb_endpoint_num(&ep->desc);
1769 		int is_out = usb_endpoint_dir_out(&ep->desc);
1770 		int is_control = usb_endpoint_xfer_control(&ep->desc);
1771 
1772 		usb_settoggle(udev, epnum, is_out, 0);
1773 		if (is_control)
1774 			usb_settoggle(udev, epnum, !is_out, 0);
1775 	}
1776 }
1777 
1778 /* Protect against drivers that try to unlink URBs after the device
1779  * is gone, by waiting until all unlinks for @udev are finished.
1780  * Since we don't currently track URBs by device, simply wait until
1781  * nothing is running in the locked region of usb_hcd_unlink_urb().
1782  */
1783 void usb_hcd_synchronize_unlinks(struct usb_device *udev)
1784 {
1785 	spin_lock_irq(&hcd_urb_unlink_lock);
1786 	spin_unlock_irq(&hcd_urb_unlink_lock);
1787 }
1788 
1789 /*-------------------------------------------------------------------------*/
1790 
1791 /* called in any context */
1792 int usb_hcd_get_frame_number (struct usb_device *udev)
1793 {
1794 	struct usb_hcd	*hcd = bus_to_hcd(udev->bus);
1795 
1796 	if (!HC_IS_RUNNING (hcd->state))
1797 		return -ESHUTDOWN;
1798 	return hcd->driver->get_frame_number (hcd);
1799 }
1800 
1801 /*-------------------------------------------------------------------------*/
1802 
1803 #ifdef	CONFIG_PM
1804 
1805 int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg)
1806 {
1807 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
1808 	int		status;
1809 	int		old_state = hcd->state;
1810 
1811 	dev_dbg(&rhdev->dev, "bus %s%s\n",
1812 			(msg.event & PM_EVENT_AUTO ? "auto-" : ""), "suspend");
1813 	if (!hcd->driver->bus_suspend) {
1814 		status = -ENOENT;
1815 	} else {
1816 		hcd->state = HC_STATE_QUIESCING;
1817 		status = hcd->driver->bus_suspend(hcd);
1818 	}
1819 	if (status == 0) {
1820 		usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
1821 		hcd->state = HC_STATE_SUSPENDED;
1822 	} else {
1823 		hcd->state = old_state;
1824 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
1825 				"suspend", status);
1826 	}
1827 	return status;
1828 }
1829 
1830 int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
1831 {
1832 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
1833 	int		status;
1834 	int		old_state = hcd->state;
1835 
1836 	dev_dbg(&rhdev->dev, "usb %s%s\n",
1837 			(msg.event & PM_EVENT_AUTO ? "auto-" : ""), "resume");
1838 	if (!hcd->driver->bus_resume)
1839 		return -ENOENT;
1840 	if (hcd->state == HC_STATE_RUNNING)
1841 		return 0;
1842 
1843 	hcd->state = HC_STATE_RESUMING;
1844 	status = hcd->driver->bus_resume(hcd);
1845 	if (status == 0) {
1846 		/* TRSMRCY = 10 msec */
1847 		msleep(10);
1848 		usb_set_device_state(rhdev, rhdev->actconfig
1849 				? USB_STATE_CONFIGURED
1850 				: USB_STATE_ADDRESS);
1851 		hcd->state = HC_STATE_RUNNING;
1852 	} else {
1853 		hcd->state = old_state;
1854 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
1855 				"resume", status);
1856 		if (status != -ESHUTDOWN)
1857 			usb_hc_died(hcd);
1858 	}
1859 	return status;
1860 }
1861 
1862 #endif	/* CONFIG_PM */
1863 
1864 #ifdef	CONFIG_USB_SUSPEND
1865 
1866 /* Workqueue routine for root-hub remote wakeup */
1867 static void hcd_resume_work(struct work_struct *work)
1868 {
1869 	struct usb_hcd *hcd = container_of(work, struct usb_hcd, wakeup_work);
1870 	struct usb_device *udev = hcd->self.root_hub;
1871 
1872 	usb_lock_device(udev);
1873 	usb_remote_wakeup(udev);
1874 	usb_unlock_device(udev);
1875 }
1876 
1877 /**
1878  * usb_hcd_resume_root_hub - called by HCD to resume its root hub
1879  * @hcd: host controller for this root hub
1880  *
1881  * The USB host controller calls this function when its root hub is
1882  * suspended (with the remote wakeup feature enabled) and a remote
1883  * wakeup request is received.  The routine submits a workqueue request
1884  * to resume the root hub (that is, manage its downstream ports again).
1885  */
1886 void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
1887 {
1888 	unsigned long flags;
1889 
1890 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
1891 	if (hcd->rh_registered)
1892 		queue_work(pm_wq, &hcd->wakeup_work);
1893 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
1894 }
1895 EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hub);
1896 
1897 #endif	/* CONFIG_USB_SUSPEND */
1898 
1899 /*-------------------------------------------------------------------------*/
1900 
1901 #ifdef	CONFIG_USB_OTG
1902 
1903 /**
1904  * usb_bus_start_enum - start immediate enumeration (for OTG)
1905  * @bus: the bus (must use hcd framework)
1906  * @port_num: 1-based number of port; usually bus->otg_port
1907  * Context: in_interrupt()
1908  *
1909  * Starts enumeration, with an immediate reset followed later by
1910  * khubd identifying and possibly configuring the device.
1911  * This is needed by OTG controller drivers, where it helps meet
1912  * HNP protocol timing requirements for starting a port reset.
1913  */
1914 int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num)
1915 {
1916 	struct usb_hcd		*hcd;
1917 	int			status = -EOPNOTSUPP;
1918 
1919 	/* NOTE: since HNP can't start by grabbing the bus's address0_sem,
1920 	 * boards with root hubs hooked up to internal devices (instead of
1921 	 * just the OTG port) may need more attention to resetting...
1922 	 */
1923 	hcd = container_of (bus, struct usb_hcd, self);
1924 	if (port_num && hcd->driver->start_port_reset)
1925 		status = hcd->driver->start_port_reset(hcd, port_num);
1926 
1927 	/* run khubd shortly after (first) root port reset finishes;
1928 	 * it may issue others, until at least 50 msecs have passed.
1929 	 */
1930 	if (status == 0)
1931 		mod_timer(&hcd->rh_timer, jiffies + msecs_to_jiffies(10));
1932 	return status;
1933 }
1934 EXPORT_SYMBOL_GPL(usb_bus_start_enum);
1935 
1936 #endif
1937 
1938 /*-------------------------------------------------------------------------*/
1939 
1940 /**
1941  * usb_hcd_irq - hook IRQs to HCD framework (bus glue)
1942  * @irq: the IRQ being raised
1943  * @__hcd: pointer to the HCD whose IRQ is being signaled
1944  *
1945  * If the controller isn't HALTed, calls the driver's irq handler.
1946  * Checks whether the controller is now dead.
1947  */
1948 irqreturn_t usb_hcd_irq (int irq, void *__hcd)
1949 {
1950 	struct usb_hcd		*hcd = __hcd;
1951 	unsigned long		flags;
1952 	irqreturn_t		rc;
1953 
1954 	/* IRQF_DISABLED doesn't work correctly with shared IRQs
1955 	 * when the first handler doesn't use it.  So let's just
1956 	 * assume it's never used.
1957 	 */
1958 	local_irq_save(flags);
1959 
1960 	if (unlikely(hcd->state == HC_STATE_HALT ||
1961 		     !test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))) {
1962 		rc = IRQ_NONE;
1963 	} else if (hcd->driver->irq(hcd) == IRQ_NONE) {
1964 		rc = IRQ_NONE;
1965 	} else {
1966 		set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
1967 
1968 		if (unlikely(hcd->state == HC_STATE_HALT))
1969 			usb_hc_died(hcd);
1970 		rc = IRQ_HANDLED;
1971 	}
1972 
1973 	local_irq_restore(flags);
1974 	return rc;
1975 }
1976 
1977 /*-------------------------------------------------------------------------*/
1978 
1979 /**
1980  * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
1981  * @hcd: pointer to the HCD representing the controller
1982  *
1983  * This is called by bus glue to report a USB host controller that died
1984  * while operations may still have been pending.  It's called automatically
1985  * by the PCI glue, so only glue for non-PCI busses should need to call it.
1986  */
1987 void usb_hc_died (struct usb_hcd *hcd)
1988 {
1989 	unsigned long flags;
1990 
1991 	dev_err (hcd->self.controller, "HC died; cleaning up\n");
1992 
1993 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
1994 	if (hcd->rh_registered) {
1995 		hcd->poll_rh = 0;
1996 
1997 		/* make khubd clean up old urbs and devices */
1998 		usb_set_device_state (hcd->self.root_hub,
1999 				USB_STATE_NOTATTACHED);
2000 		usb_kick_khubd (hcd->self.root_hub);
2001 	}
2002 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
2003 }
2004 EXPORT_SYMBOL_GPL (usb_hc_died);
2005 
2006 /*-------------------------------------------------------------------------*/
2007 
2008 /**
2009  * usb_create_hcd - create and initialize an HCD structure
2010  * @driver: HC driver that will use this hcd
2011  * @dev: device for this HC, stored in hcd->self.controller
2012  * @bus_name: value to store in hcd->self.bus_name
2013  * Context: !in_interrupt()
2014  *
2015  * Allocate a struct usb_hcd, with extra space at the end for the
2016  * HC driver's private data.  Initialize the generic members of the
2017  * hcd structure.
2018  *
2019  * If memory is unavailable, returns NULL.
2020  */
2021 struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
2022 		struct device *dev, const char *bus_name)
2023 {
2024 	struct usb_hcd *hcd;
2025 
2026 	hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
2027 	if (!hcd) {
2028 		dev_dbg (dev, "hcd alloc failed\n");
2029 		return NULL;
2030 	}
2031 	dev_set_drvdata(dev, hcd);
2032 	kref_init(&hcd->kref);
2033 
2034 	usb_bus_init(&hcd->self);
2035 	hcd->self.controller = dev;
2036 	hcd->self.bus_name = bus_name;
2037 	hcd->self.uses_dma = (dev->dma_mask != NULL);
2038 
2039 	init_timer(&hcd->rh_timer);
2040 	hcd->rh_timer.function = rh_timer_func;
2041 	hcd->rh_timer.data = (unsigned long) hcd;
2042 #ifdef CONFIG_USB_SUSPEND
2043 	INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
2044 #endif
2045 	mutex_init(&hcd->bandwidth_mutex);
2046 
2047 	hcd->driver = driver;
2048 	hcd->product_desc = (driver->product_desc) ? driver->product_desc :
2049 			"USB Host Controller";
2050 	return hcd;
2051 }
2052 EXPORT_SYMBOL_GPL(usb_create_hcd);
2053 
2054 static void hcd_release (struct kref *kref)
2055 {
2056 	struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);
2057 
2058 	kfree(hcd);
2059 }
2060 
2061 struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd)
2062 {
2063 	if (hcd)
2064 		kref_get (&hcd->kref);
2065 	return hcd;
2066 }
2067 EXPORT_SYMBOL_GPL(usb_get_hcd);
2068 
2069 void usb_put_hcd (struct usb_hcd *hcd)
2070 {
2071 	if (hcd)
2072 		kref_put (&hcd->kref, hcd_release);
2073 }
2074 EXPORT_SYMBOL_GPL(usb_put_hcd);
2075 
2076 /**
2077  * usb_add_hcd - finish generic HCD structure initialization and register
2078  * @hcd: the usb_hcd structure to initialize
2079  * @irqnum: Interrupt line to allocate
2080  * @irqflags: Interrupt type flags
2081  *
2082  * Finish the remaining parts of generic HCD initialization: allocate the
2083  * buffers of consistent memory, register the bus, request the IRQ line,
2084  * and call the driver's reset() and start() routines.
2085  */
2086 int usb_add_hcd(struct usb_hcd *hcd,
2087 		unsigned int irqnum, unsigned long irqflags)
2088 {
2089 	int retval;
2090 	struct usb_device *rhdev;
2091 
2092 	dev_info(hcd->self.controller, "%s\n", hcd->product_desc);
2093 
2094 	hcd->authorized_default = hcd->wireless? 0 : 1;
2095 	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
2096 
2097 	/* HC is in reset state, but accessible.  Now do the one-time init,
2098 	 * bottom up so that hcds can customize the root hubs before khubd
2099 	 * starts talking to them.  (Note, bus id is assigned early too.)
2100 	 */
2101 	if ((retval = hcd_buffer_create(hcd)) != 0) {
2102 		dev_dbg(hcd->self.controller, "pool alloc failed\n");
2103 		return retval;
2104 	}
2105 
2106 	if ((retval = usb_register_bus(&hcd->self)) < 0)
2107 		goto err_register_bus;
2108 
2109 	if ((rhdev = usb_alloc_dev(NULL, &hcd->self, 0)) == NULL) {
2110 		dev_err(hcd->self.controller, "unable to allocate root hub\n");
2111 		retval = -ENOMEM;
2112 		goto err_allocate_root_hub;
2113 	}
2114 
2115 	switch (hcd->driver->flags & HCD_MASK) {
2116 	case HCD_USB11:
2117 		rhdev->speed = USB_SPEED_FULL;
2118 		break;
2119 	case HCD_USB2:
2120 		rhdev->speed = USB_SPEED_HIGH;
2121 		break;
2122 	case HCD_USB3:
2123 		rhdev->speed = USB_SPEED_SUPER;
2124 		break;
2125 	default:
2126 		goto err_allocate_root_hub;
2127 	}
2128 	hcd->self.root_hub = rhdev;
2129 
2130 	/* wakeup flag init defaults to "everything works" for root hubs,
2131 	 * but drivers can override it in reset() if needed, along with
2132 	 * recording the overall controller's system wakeup capability.
2133 	 */
2134 	device_init_wakeup(&rhdev->dev, 1);
2135 
2136 	/* "reset" is misnamed; its role is now one-time init. the controller
2137 	 * should already have been reset (and boot firmware kicked off etc).
2138 	 */
2139 	if (hcd->driver->reset && (retval = hcd->driver->reset(hcd)) < 0) {
2140 		dev_err(hcd->self.controller, "can't setup\n");
2141 		goto err_hcd_driver_setup;
2142 	}
2143 
2144 	/* NOTE: root hub and controller capabilities may not be the same */
2145 	if (device_can_wakeup(hcd->self.controller)
2146 			&& device_can_wakeup(&hcd->self.root_hub->dev))
2147 		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
2148 
2149 	/* enable irqs just before we start the controller */
2150 	if (hcd->driver->irq) {
2151 
2152 		/* IRQF_DISABLED doesn't work as advertised when used together
2153 		 * with IRQF_SHARED. As usb_hcd_irq() will always disable
2154 		 * interrupts we can remove it here.
2155 		 */
2156 		if (irqflags & IRQF_SHARED)
2157 			irqflags &= ~IRQF_DISABLED;
2158 
2159 		snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
2160 				hcd->driver->description, hcd->self.busnum);
2161 		if ((retval = request_irq(irqnum, &usb_hcd_irq, irqflags,
2162 				hcd->irq_descr, hcd)) != 0) {
2163 			dev_err(hcd->self.controller,
2164 					"request interrupt %d failed\n", irqnum);
2165 			goto err_request_irq;
2166 		}
2167 		hcd->irq = irqnum;
2168 		dev_info(hcd->self.controller, "irq %d, %s 0x%08llx\n", irqnum,
2169 				(hcd->driver->flags & HCD_MEMORY) ?
2170 					"io mem" : "io base",
2171 					(unsigned long long)hcd->rsrc_start);
2172 	} else {
2173 		hcd->irq = -1;
2174 		if (hcd->rsrc_start)
2175 			dev_info(hcd->self.controller, "%s 0x%08llx\n",
2176 					(hcd->driver->flags & HCD_MEMORY) ?
2177 					"io mem" : "io base",
2178 					(unsigned long long)hcd->rsrc_start);
2179 	}
2180 
2181 	if ((retval = hcd->driver->start(hcd)) < 0) {
2182 		dev_err(hcd->self.controller, "startup error %d\n", retval);
2183 		goto err_hcd_driver_start;
2184 	}
2185 
2186 	/* starting here, usbcore will pay attention to this root hub */
2187 	rhdev->bus_mA = min(500u, hcd->power_budget);
2188 	if ((retval = register_root_hub(hcd)) != 0)
2189 		goto err_register_root_hub;
2190 
2191 	retval = sysfs_create_group(&rhdev->dev.kobj, &usb_bus_attr_group);
2192 	if (retval < 0) {
2193 		printk(KERN_ERR "Cannot register USB bus sysfs attributes: %d\n",
2194 		       retval);
2195 		goto error_create_attr_group;
2196 	}
2197 	if (hcd->uses_new_polling && hcd->poll_rh)
2198 		usb_hcd_poll_rh_status(hcd);
2199 	return retval;
2200 
2201 error_create_attr_group:
2202 	mutex_lock(&usb_bus_list_lock);
2203 	usb_disconnect(&hcd->self.root_hub);
2204 	mutex_unlock(&usb_bus_list_lock);
2205 err_register_root_hub:
2206 	hcd->driver->stop(hcd);
2207 err_hcd_driver_start:
2208 	if (hcd->irq >= 0)
2209 		free_irq(irqnum, hcd);
2210 err_request_irq:
2211 err_hcd_driver_setup:
2212 	hcd->self.root_hub = NULL;
2213 	usb_put_dev(rhdev);
2214 err_allocate_root_hub:
2215 	usb_deregister_bus(&hcd->self);
2216 err_register_bus:
2217 	hcd_buffer_destroy(hcd);
2218 	return retval;
2219 }
2220 EXPORT_SYMBOL_GPL(usb_add_hcd);
2221 
2222 /**
2223  * usb_remove_hcd - shutdown processing for generic HCDs
2224  * @hcd: the usb_hcd structure to remove
2225  * Context: !in_interrupt()
2226  *
2227  * Disconnects the root hub, then reverses the effects of usb_add_hcd(),
2228  * invoking the HCD's stop() method.
2229  */
2230 void usb_remove_hcd(struct usb_hcd *hcd)
2231 {
2232 	dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);
2233 
2234 	if (HC_IS_RUNNING (hcd->state))
2235 		hcd->state = HC_STATE_QUIESCING;
2236 
2237 	dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
2238 	spin_lock_irq (&hcd_root_hub_lock);
2239 	hcd->rh_registered = 0;
2240 	spin_unlock_irq (&hcd_root_hub_lock);
2241 
2242 #ifdef CONFIG_USB_SUSPEND
2243 	cancel_work_sync(&hcd->wakeup_work);
2244 #endif
2245 
2246 	sysfs_remove_group(&hcd->self.root_hub->dev.kobj, &usb_bus_attr_group);
2247 	mutex_lock(&usb_bus_list_lock);
2248 	usb_disconnect(&hcd->self.root_hub);
2249 	mutex_unlock(&usb_bus_list_lock);
2250 
2251 	hcd->driver->stop(hcd);
2252 	hcd->state = HC_STATE_HALT;
2253 
2254 	hcd->poll_rh = 0;
2255 	del_timer_sync(&hcd->rh_timer);
2256 
2257 	if (hcd->irq >= 0)
2258 		free_irq(hcd->irq, hcd);
2259 	usb_deregister_bus(&hcd->self);
2260 	hcd_buffer_destroy(hcd);
2261 }
2262 EXPORT_SYMBOL_GPL(usb_remove_hcd);
2263 
2264 void
2265 usb_hcd_platform_shutdown(struct platform_device* dev)
2266 {
2267 	struct usb_hcd *hcd = platform_get_drvdata(dev);
2268 
2269 	if (hcd->driver->shutdown)
2270 		hcd->driver->shutdown(hcd);
2271 }
2272 EXPORT_SYMBOL_GPL(usb_hcd_platform_shutdown);
2273 
2274 /*-------------------------------------------------------------------------*/
2275 
2276 #if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)
2277 
2278 struct usb_mon_operations *mon_ops;
2279 
2280 /*
2281  * The registration is unlocked.
2282  * We do it this way because we do not want to lock in hot paths.
2283  *
2284  * Notice that the code is minimally error-proof. Because usbmon needs
2285  * symbols from usbcore, usbcore gets referenced and cannot be unloaded first.
2286  */
2287 
2288 int usb_mon_register (struct usb_mon_operations *ops)
2289 {
2290 
2291 	if (mon_ops)
2292 		return -EBUSY;
2293 
2294 	mon_ops = ops;
2295 	mb();
2296 	return 0;
2297 }
2298 EXPORT_SYMBOL_GPL (usb_mon_register);
2299 
2300 void usb_mon_deregister (void)
2301 {
2302 
2303 	if (mon_ops == NULL) {
2304 		printk(KERN_ERR "USB: monitor was not registered\n");
2305 		return;
2306 	}
2307 	mon_ops = NULL;
2308 	mb();
2309 }
2310 EXPORT_SYMBOL_GPL (usb_mon_deregister);
2311 
2312 #endif /* CONFIG_USB_MON || CONFIG_USB_MON_MODULE */
2313