xref: /linux/drivers/usb/core/hcd.c (revision c4ee0af3fa0dc65f690fc908f02b8355f9576ea0)
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/bcd.h>
26 #include <linux/module.h>
27 #include <linux/version.h>
28 #include <linux/kernel.h>
29 #include <linux/slab.h>
30 #include <linux/completion.h>
31 #include <linux/utsname.h>
32 #include <linux/mm.h>
33 #include <asm/io.h>
34 #include <linux/device.h>
35 #include <linux/dma-mapping.h>
36 #include <linux/mutex.h>
37 #include <asm/irq.h>
38 #include <asm/byteorder.h>
39 #include <asm/unaligned.h>
40 #include <linux/platform_device.h>
41 #include <linux/workqueue.h>
42 #include <linux/pm_runtime.h>
43 #include <linux/types.h>
44 
45 #include <linux/usb.h>
46 #include <linux/usb/hcd.h>
47 
48 #include "usb.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 static DECLARE_BITMAP(busmap, USB_MAXBUS);
97 
98 /* used when updating list of hcds */
99 DEFINE_MUTEX(usb_bus_list_lock);	/* exported only for usbfs */
100 EXPORT_SYMBOL_GPL (usb_bus_list_lock);
101 
102 /* used for controlling access to virtual root hubs */
103 static DEFINE_SPINLOCK(hcd_root_hub_lock);
104 
105 /* used when updating an endpoint's URB list */
106 static DEFINE_SPINLOCK(hcd_urb_list_lock);
107 
108 /* used to protect against unlinking URBs after the device is gone */
109 static DEFINE_SPINLOCK(hcd_urb_unlink_lock);
110 
111 /* wait queue for synchronous unlinks */
112 DECLARE_WAIT_QUEUE_HEAD(usb_kill_urb_queue);
113 
114 static inline int is_root_hub(struct usb_device *udev)
115 {
116 	return (udev->parent == NULL);
117 }
118 
119 /*-------------------------------------------------------------------------*/
120 
121 /*
122  * Sharable chunks of root hub code.
123  */
124 
125 /*-------------------------------------------------------------------------*/
126 #define KERNEL_REL	bin2bcd(((LINUX_VERSION_CODE >> 16) & 0x0ff))
127 #define KERNEL_VER	bin2bcd(((LINUX_VERSION_CODE >> 8) & 0x0ff))
128 
129 /* usb 3.0 root hub device descriptor */
130 static const u8 usb3_rh_dev_descriptor[18] = {
131 	0x12,       /*  __u8  bLength; */
132 	0x01,       /*  __u8  bDescriptorType; Device */
133 	0x00, 0x03, /*  __le16 bcdUSB; v3.0 */
134 
135 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
136 	0x00,	    /*  __u8  bDeviceSubClass; */
137 	0x03,       /*  __u8  bDeviceProtocol; USB 3.0 hub */
138 	0x09,       /*  __u8  bMaxPacketSize0; 2^9 = 512 Bytes */
139 
140 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation 0x1d6b */
141 	0x03, 0x00, /*  __le16 idProduct; device 0x0003 */
142 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
143 
144 	0x03,       /*  __u8  iManufacturer; */
145 	0x02,       /*  __u8  iProduct; */
146 	0x01,       /*  __u8  iSerialNumber; */
147 	0x01        /*  __u8  bNumConfigurations; */
148 };
149 
150 /* usb 2.5 (wireless USB 1.0) root hub device descriptor */
151 static const u8 usb25_rh_dev_descriptor[18] = {
152 	0x12,       /*  __u8  bLength; */
153 	0x01,       /*  __u8  bDescriptorType; Device */
154 	0x50, 0x02, /*  __le16 bcdUSB; v2.5 */
155 
156 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
157 	0x00,	    /*  __u8  bDeviceSubClass; */
158 	0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
159 	0xFF,       /*  __u8  bMaxPacketSize0; always 0xFF (WUSB Spec 7.4.1). */
160 
161 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation 0x1d6b */
162 	0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
163 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
164 
165 	0x03,       /*  __u8  iManufacturer; */
166 	0x02,       /*  __u8  iProduct; */
167 	0x01,       /*  __u8  iSerialNumber; */
168 	0x01        /*  __u8  bNumConfigurations; */
169 };
170 
171 /* usb 2.0 root hub device descriptor */
172 static const u8 usb2_rh_dev_descriptor[18] = {
173 	0x12,       /*  __u8  bLength; */
174 	0x01,       /*  __u8  bDescriptorType; Device */
175 	0x00, 0x02, /*  __le16 bcdUSB; v2.0 */
176 
177 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
178 	0x00,	    /*  __u8  bDeviceSubClass; */
179 	0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
180 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
181 
182 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation 0x1d6b */
183 	0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
184 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
185 
186 	0x03,       /*  __u8  iManufacturer; */
187 	0x02,       /*  __u8  iProduct; */
188 	0x01,       /*  __u8  iSerialNumber; */
189 	0x01        /*  __u8  bNumConfigurations; */
190 };
191 
192 /* no usb 2.0 root hub "device qualifier" descriptor: one speed only */
193 
194 /* usb 1.1 root hub device descriptor */
195 static const u8 usb11_rh_dev_descriptor[18] = {
196 	0x12,       /*  __u8  bLength; */
197 	0x01,       /*  __u8  bDescriptorType; Device */
198 	0x10, 0x01, /*  __le16 bcdUSB; v1.1 */
199 
200 	0x09,	    /*  __u8  bDeviceClass; HUB_CLASSCODE */
201 	0x00,	    /*  __u8  bDeviceSubClass; */
202 	0x00,       /*  __u8  bDeviceProtocol; [ low/full speeds only ] */
203 	0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */
204 
205 	0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation 0x1d6b */
206 	0x01, 0x00, /*  __le16 idProduct; device 0x0001 */
207 	KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */
208 
209 	0x03,       /*  __u8  iManufacturer; */
210 	0x02,       /*  __u8  iProduct; */
211 	0x01,       /*  __u8  iSerialNumber; */
212 	0x01        /*  __u8  bNumConfigurations; */
213 };
214 
215 
216 /*-------------------------------------------------------------------------*/
217 
218 /* Configuration descriptors for our root hubs */
219 
220 static const u8 fs_rh_config_descriptor[] = {
221 
222 	/* one configuration */
223 	0x09,       /*  __u8  bLength; */
224 	0x02,       /*  __u8  bDescriptorType; Configuration */
225 	0x19, 0x00, /*  __le16 wTotalLength; */
226 	0x01,       /*  __u8  bNumInterfaces; (1) */
227 	0x01,       /*  __u8  bConfigurationValue; */
228 	0x00,       /*  __u8  iConfiguration; */
229 	0xc0,       /*  __u8  bmAttributes;
230 				 Bit 7: must be set,
231 				     6: Self-powered,
232 				     5: Remote wakeup,
233 				     4..0: resvd */
234 	0x00,       /*  __u8  MaxPower; */
235 
236 	/* USB 1.1:
237 	 * USB 2.0, single TT organization (mandatory):
238 	 *	one interface, protocol 0
239 	 *
240 	 * USB 2.0, multiple TT organization (optional):
241 	 *	two interfaces, protocols 1 (like single TT)
242 	 *	and 2 (multiple TT mode) ... config is
243 	 *	sometimes settable
244 	 *	NOT IMPLEMENTED
245 	 */
246 
247 	/* one interface */
248 	0x09,       /*  __u8  if_bLength; */
249 	0x04,       /*  __u8  if_bDescriptorType; Interface */
250 	0x00,       /*  __u8  if_bInterfaceNumber; */
251 	0x00,       /*  __u8  if_bAlternateSetting; */
252 	0x01,       /*  __u8  if_bNumEndpoints; */
253 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
254 	0x00,       /*  __u8  if_bInterfaceSubClass; */
255 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
256 	0x00,       /*  __u8  if_iInterface; */
257 
258 	/* one endpoint (status change endpoint) */
259 	0x07,       /*  __u8  ep_bLength; */
260 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
261 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
262 	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
263 	0x02, 0x00, /*  __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) */
264 	0xff        /*  __u8  ep_bInterval; (255ms -- usb 2.0 spec) */
265 };
266 
267 static const u8 hs_rh_config_descriptor[] = {
268 
269 	/* one configuration */
270 	0x09,       /*  __u8  bLength; */
271 	0x02,       /*  __u8  bDescriptorType; Configuration */
272 	0x19, 0x00, /*  __le16 wTotalLength; */
273 	0x01,       /*  __u8  bNumInterfaces; (1) */
274 	0x01,       /*  __u8  bConfigurationValue; */
275 	0x00,       /*  __u8  iConfiguration; */
276 	0xc0,       /*  __u8  bmAttributes;
277 				 Bit 7: must be set,
278 				     6: Self-powered,
279 				     5: Remote wakeup,
280 				     4..0: resvd */
281 	0x00,       /*  __u8  MaxPower; */
282 
283 	/* USB 1.1:
284 	 * USB 2.0, single TT organization (mandatory):
285 	 *	one interface, protocol 0
286 	 *
287 	 * USB 2.0, multiple TT organization (optional):
288 	 *	two interfaces, protocols 1 (like single TT)
289 	 *	and 2 (multiple TT mode) ... config is
290 	 *	sometimes settable
291 	 *	NOT IMPLEMENTED
292 	 */
293 
294 	/* one interface */
295 	0x09,       /*  __u8  if_bLength; */
296 	0x04,       /*  __u8  if_bDescriptorType; Interface */
297 	0x00,       /*  __u8  if_bInterfaceNumber; */
298 	0x00,       /*  __u8  if_bAlternateSetting; */
299 	0x01,       /*  __u8  if_bNumEndpoints; */
300 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
301 	0x00,       /*  __u8  if_bInterfaceSubClass; */
302 	0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
303 	0x00,       /*  __u8  if_iInterface; */
304 
305 	/* one endpoint (status change endpoint) */
306 	0x07,       /*  __u8  ep_bLength; */
307 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
308 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
309 	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
310 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
311 		     * see hub.c:hub_configure() for details. */
312 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
313 	0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
314 };
315 
316 static const u8 ss_rh_config_descriptor[] = {
317 	/* one configuration */
318 	0x09,       /*  __u8  bLength; */
319 	0x02,       /*  __u8  bDescriptorType; Configuration */
320 	0x1f, 0x00, /*  __le16 wTotalLength; */
321 	0x01,       /*  __u8  bNumInterfaces; (1) */
322 	0x01,       /*  __u8  bConfigurationValue; */
323 	0x00,       /*  __u8  iConfiguration; */
324 	0xc0,       /*  __u8  bmAttributes;
325 				 Bit 7: must be set,
326 				     6: Self-powered,
327 				     5: Remote wakeup,
328 				     4..0: resvd */
329 	0x00,       /*  __u8  MaxPower; */
330 
331 	/* one interface */
332 	0x09,       /*  __u8  if_bLength; */
333 	0x04,       /*  __u8  if_bDescriptorType; Interface */
334 	0x00,       /*  __u8  if_bInterfaceNumber; */
335 	0x00,       /*  __u8  if_bAlternateSetting; */
336 	0x01,       /*  __u8  if_bNumEndpoints; */
337 	0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
338 	0x00,       /*  __u8  if_bInterfaceSubClass; */
339 	0x00,       /*  __u8  if_bInterfaceProtocol; */
340 	0x00,       /*  __u8  if_iInterface; */
341 
342 	/* one endpoint (status change endpoint) */
343 	0x07,       /*  __u8  ep_bLength; */
344 	0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
345 	0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
346 	0x03,       /*  __u8  ep_bmAttributes; Interrupt */
347 		    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
348 		     * see hub.c:hub_configure() for details. */
349 	(USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
350 	0x0c,       /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
351 
352 	/* one SuperSpeed endpoint companion descriptor */
353 	0x06,        /* __u8 ss_bLength */
354 	0x30,        /* __u8 ss_bDescriptorType; SuperSpeed EP Companion */
355 	0x00,        /* __u8 ss_bMaxBurst; allows 1 TX between ACKs */
356 	0x00,        /* __u8 ss_bmAttributes; 1 packet per service interval */
357 	0x02, 0x00   /* __le16 ss_wBytesPerInterval; 15 bits for max 15 ports */
358 };
359 
360 /* authorized_default behaviour:
361  * -1 is authorized for all devices except wireless (old behaviour)
362  * 0 is unauthorized for all devices
363  * 1 is authorized for all devices
364  */
365 static int authorized_default = -1;
366 module_param(authorized_default, int, S_IRUGO|S_IWUSR);
367 MODULE_PARM_DESC(authorized_default,
368 		"Default USB device authorization: 0 is not authorized, 1 is "
369 		"authorized, -1 is authorized except for wireless USB (default, "
370 		"old behaviour");
371 /*-------------------------------------------------------------------------*/
372 
373 /**
374  * ascii2desc() - Helper routine for producing UTF-16LE string descriptors
375  * @s: Null-terminated ASCII (actually ISO-8859-1) string
376  * @buf: Buffer for USB string descriptor (header + UTF-16LE)
377  * @len: Length (in bytes; may be odd) of descriptor buffer.
378  *
379  * Return: The number of bytes filled in: 2 + 2*strlen(s) or @len,
380  * whichever is less.
381  *
382  * Note:
383  * USB String descriptors can contain at most 126 characters; input
384  * strings longer than that are truncated.
385  */
386 static unsigned
387 ascii2desc(char const *s, u8 *buf, unsigned len)
388 {
389 	unsigned n, t = 2 + 2*strlen(s);
390 
391 	if (t > 254)
392 		t = 254;	/* Longest possible UTF string descriptor */
393 	if (len > t)
394 		len = t;
395 
396 	t += USB_DT_STRING << 8;	/* Now t is first 16 bits to store */
397 
398 	n = len;
399 	while (n--) {
400 		*buf++ = t;
401 		if (!n--)
402 			break;
403 		*buf++ = t >> 8;
404 		t = (unsigned char)*s++;
405 	}
406 	return len;
407 }
408 
409 /**
410  * rh_string() - provides string descriptors for root hub
411  * @id: the string ID number (0: langids, 1: serial #, 2: product, 3: vendor)
412  * @hcd: the host controller for this root hub
413  * @data: buffer for output packet
414  * @len: length of the provided buffer
415  *
416  * Produces either a manufacturer, product or serial number string for the
417  * virtual root hub device.
418  *
419  * Return: The number of bytes filled in: the length of the descriptor or
420  * of the provided buffer, whichever is less.
421  */
422 static unsigned
423 rh_string(int id, struct usb_hcd const *hcd, u8 *data, unsigned len)
424 {
425 	char buf[100];
426 	char const *s;
427 	static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04};
428 
429 	/* language ids */
430 	switch (id) {
431 	case 0:
432 		/* Array of LANGID codes (0x0409 is MSFT-speak for "en-us") */
433 		/* See http://www.usb.org/developers/docs/USB_LANGIDs.pdf */
434 		if (len > 4)
435 			len = 4;
436 		memcpy(data, langids, len);
437 		return len;
438 	case 1:
439 		/* Serial number */
440 		s = hcd->self.bus_name;
441 		break;
442 	case 2:
443 		/* Product name */
444 		s = hcd->product_desc;
445 		break;
446 	case 3:
447 		/* Manufacturer */
448 		snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
449 			init_utsname()->release, hcd->driver->description);
450 		s = buf;
451 		break;
452 	default:
453 		/* Can't happen; caller guarantees it */
454 		return 0;
455 	}
456 
457 	return ascii2desc(s, data, len);
458 }
459 
460 
461 /* Root hub control transfers execute synchronously */
462 static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
463 {
464 	struct usb_ctrlrequest *cmd;
465 	u16		typeReq, wValue, wIndex, wLength;
466 	u8		*ubuf = urb->transfer_buffer;
467 	unsigned	len = 0;
468 	int		status;
469 	u8		patch_wakeup = 0;
470 	u8		patch_protocol = 0;
471 	u16		tbuf_size;
472 	u8		*tbuf = NULL;
473 	const u8	*bufp;
474 
475 	might_sleep();
476 
477 	spin_lock_irq(&hcd_root_hub_lock);
478 	status = usb_hcd_link_urb_to_ep(hcd, urb);
479 	spin_unlock_irq(&hcd_root_hub_lock);
480 	if (status)
481 		return status;
482 	urb->hcpriv = hcd;	/* Indicate it's queued */
483 
484 	cmd = (struct usb_ctrlrequest *) urb->setup_packet;
485 	typeReq  = (cmd->bRequestType << 8) | cmd->bRequest;
486 	wValue   = le16_to_cpu (cmd->wValue);
487 	wIndex   = le16_to_cpu (cmd->wIndex);
488 	wLength  = le16_to_cpu (cmd->wLength);
489 
490 	if (wLength > urb->transfer_buffer_length)
491 		goto error;
492 
493 	/*
494 	 * tbuf should be at least as big as the
495 	 * USB hub descriptor.
496 	 */
497 	tbuf_size =  max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
498 	tbuf = kzalloc(tbuf_size, GFP_KERNEL);
499 	if (!tbuf)
500 		return -ENOMEM;
501 
502 	bufp = tbuf;
503 
504 
505 	urb->actual_length = 0;
506 	switch (typeReq) {
507 
508 	/* DEVICE REQUESTS */
509 
510 	/* The root hub's remote wakeup enable bit is implemented using
511 	 * driver model wakeup flags.  If this system supports wakeup
512 	 * through USB, userspace may change the default "allow wakeup"
513 	 * policy through sysfs or these calls.
514 	 *
515 	 * Most root hubs support wakeup from downstream devices, for
516 	 * runtime power management (disabling USB clocks and reducing
517 	 * VBUS power usage).  However, not all of them do so; silicon,
518 	 * board, and BIOS bugs here are not uncommon, so these can't
519 	 * be treated quite like external hubs.
520 	 *
521 	 * Likewise, not all root hubs will pass wakeup events upstream,
522 	 * to wake up the whole system.  So don't assume root hub and
523 	 * controller capabilities are identical.
524 	 */
525 
526 	case DeviceRequest | USB_REQ_GET_STATUS:
527 		tbuf[0] = (device_may_wakeup(&hcd->self.root_hub->dev)
528 					<< USB_DEVICE_REMOTE_WAKEUP)
529 				| (1 << USB_DEVICE_SELF_POWERED);
530 		tbuf[1] = 0;
531 		len = 2;
532 		break;
533 	case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
534 		if (wValue == USB_DEVICE_REMOTE_WAKEUP)
535 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 0);
536 		else
537 			goto error;
538 		break;
539 	case DeviceOutRequest | USB_REQ_SET_FEATURE:
540 		if (device_can_wakeup(&hcd->self.root_hub->dev)
541 				&& wValue == USB_DEVICE_REMOTE_WAKEUP)
542 			device_set_wakeup_enable(&hcd->self.root_hub->dev, 1);
543 		else
544 			goto error;
545 		break;
546 	case DeviceRequest | USB_REQ_GET_CONFIGURATION:
547 		tbuf[0] = 1;
548 		len = 1;
549 			/* FALLTHROUGH */
550 	case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
551 		break;
552 	case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
553 		switch (wValue & 0xff00) {
554 		case USB_DT_DEVICE << 8:
555 			switch (hcd->speed) {
556 			case HCD_USB3:
557 				bufp = usb3_rh_dev_descriptor;
558 				break;
559 			case HCD_USB25:
560 				bufp = usb25_rh_dev_descriptor;
561 				break;
562 			case HCD_USB2:
563 				bufp = usb2_rh_dev_descriptor;
564 				break;
565 			case HCD_USB11:
566 				bufp = usb11_rh_dev_descriptor;
567 				break;
568 			default:
569 				goto error;
570 			}
571 			len = 18;
572 			if (hcd->has_tt)
573 				patch_protocol = 1;
574 			break;
575 		case USB_DT_CONFIG << 8:
576 			switch (hcd->speed) {
577 			case HCD_USB3:
578 				bufp = ss_rh_config_descriptor;
579 				len = sizeof ss_rh_config_descriptor;
580 				break;
581 			case HCD_USB25:
582 			case HCD_USB2:
583 				bufp = hs_rh_config_descriptor;
584 				len = sizeof hs_rh_config_descriptor;
585 				break;
586 			case HCD_USB11:
587 				bufp = fs_rh_config_descriptor;
588 				len = sizeof fs_rh_config_descriptor;
589 				break;
590 			default:
591 				goto error;
592 			}
593 			if (device_can_wakeup(&hcd->self.root_hub->dev))
594 				patch_wakeup = 1;
595 			break;
596 		case USB_DT_STRING << 8:
597 			if ((wValue & 0xff) < 4)
598 				urb->actual_length = rh_string(wValue & 0xff,
599 						hcd, ubuf, wLength);
600 			else /* unsupported IDs --> "protocol stall" */
601 				goto error;
602 			break;
603 		case USB_DT_BOS << 8:
604 			goto nongeneric;
605 		default:
606 			goto error;
607 		}
608 		break;
609 	case DeviceRequest | USB_REQ_GET_INTERFACE:
610 		tbuf[0] = 0;
611 		len = 1;
612 			/* FALLTHROUGH */
613 	case DeviceOutRequest | USB_REQ_SET_INTERFACE:
614 		break;
615 	case DeviceOutRequest | USB_REQ_SET_ADDRESS:
616 		/* wValue == urb->dev->devaddr */
617 		dev_dbg (hcd->self.controller, "root hub device address %d\n",
618 			wValue);
619 		break;
620 
621 	/* INTERFACE REQUESTS (no defined feature/status flags) */
622 
623 	/* ENDPOINT REQUESTS */
624 
625 	case EndpointRequest | USB_REQ_GET_STATUS:
626 		/* ENDPOINT_HALT flag */
627 		tbuf[0] = 0;
628 		tbuf[1] = 0;
629 		len = 2;
630 			/* FALLTHROUGH */
631 	case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
632 	case EndpointOutRequest | USB_REQ_SET_FEATURE:
633 		dev_dbg (hcd->self.controller, "no endpoint features yet\n");
634 		break;
635 
636 	/* CLASS REQUESTS (and errors) */
637 
638 	default:
639 nongeneric:
640 		/* non-generic request */
641 		switch (typeReq) {
642 		case GetHubStatus:
643 		case GetPortStatus:
644 			len = 4;
645 			break;
646 		case GetHubDescriptor:
647 			len = sizeof (struct usb_hub_descriptor);
648 			break;
649 		case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
650 			/* len is returned by hub_control */
651 			break;
652 		}
653 		status = hcd->driver->hub_control (hcd,
654 			typeReq, wValue, wIndex,
655 			tbuf, wLength);
656 
657 		if (typeReq == GetHubDescriptor)
658 			usb_hub_adjust_deviceremovable(hcd->self.root_hub,
659 				(struct usb_hub_descriptor *)tbuf);
660 		break;
661 error:
662 		/* "protocol stall" on error */
663 		status = -EPIPE;
664 	}
665 
666 	if (status < 0) {
667 		len = 0;
668 		if (status != -EPIPE) {
669 			dev_dbg (hcd->self.controller,
670 				"CTRL: TypeReq=0x%x val=0x%x "
671 				"idx=0x%x len=%d ==> %d\n",
672 				typeReq, wValue, wIndex,
673 				wLength, status);
674 		}
675 	} else if (status > 0) {
676 		/* hub_control may return the length of data copied. */
677 		len = status;
678 		status = 0;
679 	}
680 	if (len) {
681 		if (urb->transfer_buffer_length < len)
682 			len = urb->transfer_buffer_length;
683 		urb->actual_length = len;
684 		/* always USB_DIR_IN, toward host */
685 		memcpy (ubuf, bufp, len);
686 
687 		/* report whether RH hardware supports remote wakeup */
688 		if (patch_wakeup &&
689 				len > offsetof (struct usb_config_descriptor,
690 						bmAttributes))
691 			((struct usb_config_descriptor *)ubuf)->bmAttributes
692 				|= USB_CONFIG_ATT_WAKEUP;
693 
694 		/* report whether RH hardware has an integrated TT */
695 		if (patch_protocol &&
696 				len > offsetof(struct usb_device_descriptor,
697 						bDeviceProtocol))
698 			((struct usb_device_descriptor *) ubuf)->
699 				bDeviceProtocol = USB_HUB_PR_HS_SINGLE_TT;
700 	}
701 
702 	kfree(tbuf);
703 
704 	/* any errors get returned through the urb completion */
705 	spin_lock_irq(&hcd_root_hub_lock);
706 	usb_hcd_unlink_urb_from_ep(hcd, urb);
707 	usb_hcd_giveback_urb(hcd, urb, status);
708 	spin_unlock_irq(&hcd_root_hub_lock);
709 	return 0;
710 }
711 
712 /*-------------------------------------------------------------------------*/
713 
714 /*
715  * Root Hub interrupt transfers are polled using a timer if the
716  * driver requests it; otherwise the driver is responsible for
717  * calling usb_hcd_poll_rh_status() when an event occurs.
718  *
719  * Completions are called in_interrupt(), but they may or may not
720  * be in_irq().
721  */
722 void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
723 {
724 	struct urb	*urb;
725 	int		length;
726 	unsigned long	flags;
727 	char		buffer[6];	/* Any root hubs with > 31 ports? */
728 
729 	if (unlikely(!hcd->rh_pollable))
730 		return;
731 	if (!hcd->uses_new_polling && !hcd->status_urb)
732 		return;
733 
734 	length = hcd->driver->hub_status_data(hcd, buffer);
735 	if (length > 0) {
736 
737 		/* try to complete the status urb */
738 		spin_lock_irqsave(&hcd_root_hub_lock, flags);
739 		urb = hcd->status_urb;
740 		if (urb) {
741 			clear_bit(HCD_FLAG_POLL_PENDING, &hcd->flags);
742 			hcd->status_urb = NULL;
743 			urb->actual_length = length;
744 			memcpy(urb->transfer_buffer, buffer, length);
745 
746 			usb_hcd_unlink_urb_from_ep(hcd, urb);
747 			usb_hcd_giveback_urb(hcd, urb, 0);
748 		} else {
749 			length = 0;
750 			set_bit(HCD_FLAG_POLL_PENDING, &hcd->flags);
751 		}
752 		spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
753 	}
754 
755 	/* The USB 2.0 spec says 256 ms.  This is close enough and won't
756 	 * exceed that limit if HZ is 100. The math is more clunky than
757 	 * maybe expected, this is to make sure that all timers for USB devices
758 	 * fire at the same time to give the CPU a break in between */
759 	if (hcd->uses_new_polling ? HCD_POLL_RH(hcd) :
760 			(length == 0 && hcd->status_urb != NULL))
761 		mod_timer (&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
762 }
763 EXPORT_SYMBOL_GPL(usb_hcd_poll_rh_status);
764 
765 /* timer callback */
766 static void rh_timer_func (unsigned long _hcd)
767 {
768 	usb_hcd_poll_rh_status((struct usb_hcd *) _hcd);
769 }
770 
771 /*-------------------------------------------------------------------------*/
772 
773 static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
774 {
775 	int		retval;
776 	unsigned long	flags;
777 	unsigned	len = 1 + (urb->dev->maxchild / 8);
778 
779 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
780 	if (hcd->status_urb || urb->transfer_buffer_length < len) {
781 		dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
782 		retval = -EINVAL;
783 		goto done;
784 	}
785 
786 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
787 	if (retval)
788 		goto done;
789 
790 	hcd->status_urb = urb;
791 	urb->hcpriv = hcd;	/* indicate it's queued */
792 	if (!hcd->uses_new_polling)
793 		mod_timer(&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
794 
795 	/* If a status change has already occurred, report it ASAP */
796 	else if (HCD_POLL_PENDING(hcd))
797 		mod_timer(&hcd->rh_timer, jiffies);
798 	retval = 0;
799  done:
800 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
801 	return retval;
802 }
803 
804 static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
805 {
806 	if (usb_endpoint_xfer_int(&urb->ep->desc))
807 		return rh_queue_status (hcd, urb);
808 	if (usb_endpoint_xfer_control(&urb->ep->desc))
809 		return rh_call_control (hcd, urb);
810 	return -EINVAL;
811 }
812 
813 /*-------------------------------------------------------------------------*/
814 
815 /* Unlinks of root-hub control URBs are legal, but they don't do anything
816  * since these URBs always execute synchronously.
817  */
818 static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
819 {
820 	unsigned long	flags;
821 	int		rc;
822 
823 	spin_lock_irqsave(&hcd_root_hub_lock, flags);
824 	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
825 	if (rc)
826 		goto done;
827 
828 	if (usb_endpoint_num(&urb->ep->desc) == 0) {	/* Control URB */
829 		;	/* Do nothing */
830 
831 	} else {				/* Status URB */
832 		if (!hcd->uses_new_polling)
833 			del_timer (&hcd->rh_timer);
834 		if (urb == hcd->status_urb) {
835 			hcd->status_urb = NULL;
836 			usb_hcd_unlink_urb_from_ep(hcd, urb);
837 			usb_hcd_giveback_urb(hcd, urb, status);
838 		}
839 	}
840  done:
841 	spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
842 	return rc;
843 }
844 
845 
846 
847 /*
848  * Show & store the current value of authorized_default
849  */
850 static ssize_t authorized_default_show(struct device *dev,
851 				       struct device_attribute *attr, char *buf)
852 {
853 	struct usb_device *rh_usb_dev = to_usb_device(dev);
854 	struct usb_bus *usb_bus = rh_usb_dev->bus;
855 	struct usb_hcd *usb_hcd;
856 
857 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
858 		return -ENODEV;
859 	usb_hcd = bus_to_hcd(usb_bus);
860 	return snprintf(buf, PAGE_SIZE, "%u\n", usb_hcd->authorized_default);
861 }
862 
863 static ssize_t authorized_default_store(struct device *dev,
864 					struct device_attribute *attr,
865 					const char *buf, size_t size)
866 {
867 	ssize_t result;
868 	unsigned val;
869 	struct usb_device *rh_usb_dev = to_usb_device(dev);
870 	struct usb_bus *usb_bus = rh_usb_dev->bus;
871 	struct usb_hcd *usb_hcd;
872 
873 	if (usb_bus == NULL)	/* FIXME: not sure if this case is possible */
874 		return -ENODEV;
875 	usb_hcd = bus_to_hcd(usb_bus);
876 	result = sscanf(buf, "%u\n", &val);
877 	if (result == 1) {
878 		usb_hcd->authorized_default = val ? 1 : 0;
879 		result = size;
880 	} else {
881 		result = -EINVAL;
882 	}
883 	return result;
884 }
885 static DEVICE_ATTR_RW(authorized_default);
886 
887 /* Group all the USB bus attributes */
888 static struct attribute *usb_bus_attrs[] = {
889 		&dev_attr_authorized_default.attr,
890 		NULL,
891 };
892 
893 static struct attribute_group usb_bus_attr_group = {
894 	.name = NULL,	/* we want them in the same directory */
895 	.attrs = usb_bus_attrs,
896 };
897 
898 
899 
900 /*-------------------------------------------------------------------------*/
901 
902 /**
903  * usb_bus_init - shared initialization code
904  * @bus: the bus structure being initialized
905  *
906  * This code is used to initialize a usb_bus structure, memory for which is
907  * separately managed.
908  */
909 static void usb_bus_init (struct usb_bus *bus)
910 {
911 	memset (&bus->devmap, 0, sizeof(struct usb_devmap));
912 
913 	bus->devnum_next = 1;
914 
915 	bus->root_hub = NULL;
916 	bus->busnum = -1;
917 	bus->bandwidth_allocated = 0;
918 	bus->bandwidth_int_reqs  = 0;
919 	bus->bandwidth_isoc_reqs = 0;
920 
921 	INIT_LIST_HEAD (&bus->bus_list);
922 }
923 
924 /*-------------------------------------------------------------------------*/
925 
926 /**
927  * usb_register_bus - registers the USB host controller with the usb core
928  * @bus: pointer to the bus to register
929  * Context: !in_interrupt()
930  *
931  * Assigns a bus number, and links the controller into usbcore data
932  * structures so that it can be seen by scanning the bus list.
933  *
934  * Return: 0 if successful. A negative error code otherwise.
935  */
936 static int usb_register_bus(struct usb_bus *bus)
937 {
938 	int result = -E2BIG;
939 	int busnum;
940 
941 	mutex_lock(&usb_bus_list_lock);
942 	busnum = find_next_zero_bit(busmap, USB_MAXBUS, 1);
943 	if (busnum >= USB_MAXBUS) {
944 		printk (KERN_ERR "%s: too many buses\n", usbcore_name);
945 		goto error_find_busnum;
946 	}
947 	set_bit(busnum, busmap);
948 	bus->busnum = busnum;
949 
950 	/* Add it to the local list of buses */
951 	list_add (&bus->bus_list, &usb_bus_list);
952 	mutex_unlock(&usb_bus_list_lock);
953 
954 	usb_notify_add_bus(bus);
955 
956 	dev_info (bus->controller, "new USB bus registered, assigned bus "
957 		  "number %d\n", bus->busnum);
958 	return 0;
959 
960 error_find_busnum:
961 	mutex_unlock(&usb_bus_list_lock);
962 	return result;
963 }
964 
965 /**
966  * usb_deregister_bus - deregisters the USB host controller
967  * @bus: pointer to the bus to deregister
968  * Context: !in_interrupt()
969  *
970  * Recycles the bus number, and unlinks the controller from usbcore data
971  * structures so that it won't be seen by scanning the bus list.
972  */
973 static void usb_deregister_bus (struct usb_bus *bus)
974 {
975 	dev_info (bus->controller, "USB bus %d deregistered\n", bus->busnum);
976 
977 	/*
978 	 * NOTE: make sure that all the devices are removed by the
979 	 * controller code, as well as having it call this when cleaning
980 	 * itself up
981 	 */
982 	mutex_lock(&usb_bus_list_lock);
983 	list_del (&bus->bus_list);
984 	mutex_unlock(&usb_bus_list_lock);
985 
986 	usb_notify_remove_bus(bus);
987 
988 	clear_bit(bus->busnum, busmap);
989 }
990 
991 /**
992  * register_root_hub - called by usb_add_hcd() to register a root hub
993  * @hcd: host controller for this root hub
994  *
995  * This function registers the root hub with the USB subsystem.  It sets up
996  * the device properly in the device tree and then calls usb_new_device()
997  * to register the usb device.  It also assigns the root hub's USB address
998  * (always 1).
999  *
1000  * Return: 0 if successful. A negative error code otherwise.
1001  */
1002 static int register_root_hub(struct usb_hcd *hcd)
1003 {
1004 	struct device *parent_dev = hcd->self.controller;
1005 	struct usb_device *usb_dev = hcd->self.root_hub;
1006 	const int devnum = 1;
1007 	int retval;
1008 
1009 	usb_dev->devnum = devnum;
1010 	usb_dev->bus->devnum_next = devnum + 1;
1011 	memset (&usb_dev->bus->devmap.devicemap, 0,
1012 			sizeof usb_dev->bus->devmap.devicemap);
1013 	set_bit (devnum, usb_dev->bus->devmap.devicemap);
1014 	usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
1015 
1016 	mutex_lock(&usb_bus_list_lock);
1017 
1018 	usb_dev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
1019 	retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE);
1020 	if (retval != sizeof usb_dev->descriptor) {
1021 		mutex_unlock(&usb_bus_list_lock);
1022 		dev_dbg (parent_dev, "can't read %s device descriptor %d\n",
1023 				dev_name(&usb_dev->dev), retval);
1024 		return (retval < 0) ? retval : -EMSGSIZE;
1025 	}
1026 	if (usb_dev->speed == USB_SPEED_SUPER) {
1027 		retval = usb_get_bos_descriptor(usb_dev);
1028 		if (retval < 0) {
1029 			mutex_unlock(&usb_bus_list_lock);
1030 			dev_dbg(parent_dev, "can't read %s bos descriptor %d\n",
1031 					dev_name(&usb_dev->dev), retval);
1032 			return retval;
1033 		}
1034 		usb_dev->lpm_capable = usb_device_supports_lpm(usb_dev);
1035 	}
1036 
1037 	retval = usb_new_device (usb_dev);
1038 	if (retval) {
1039 		dev_err (parent_dev, "can't register root hub for %s, %d\n",
1040 				dev_name(&usb_dev->dev), retval);
1041 	} else {
1042 		spin_lock_irq (&hcd_root_hub_lock);
1043 		hcd->rh_registered = 1;
1044 		spin_unlock_irq (&hcd_root_hub_lock);
1045 
1046 		/* Did the HC die before the root hub was registered? */
1047 		if (HCD_DEAD(hcd))
1048 			usb_hc_died (hcd);	/* This time clean up */
1049 	}
1050 	mutex_unlock(&usb_bus_list_lock);
1051 
1052 	return retval;
1053 }
1054 
1055 /*
1056  * usb_hcd_start_port_resume - a root-hub port is sending a resume signal
1057  * @bus: the bus which the root hub belongs to
1058  * @portnum: the port which is being resumed
1059  *
1060  * HCDs should call this function when they know that a resume signal is
1061  * being sent to a root-hub port.  The root hub will be prevented from
1062  * going into autosuspend until usb_hcd_end_port_resume() is called.
1063  *
1064  * The bus's private lock must be held by the caller.
1065  */
1066 void usb_hcd_start_port_resume(struct usb_bus *bus, int portnum)
1067 {
1068 	unsigned bit = 1 << portnum;
1069 
1070 	if (!(bus->resuming_ports & bit)) {
1071 		bus->resuming_ports |= bit;
1072 		pm_runtime_get_noresume(&bus->root_hub->dev);
1073 	}
1074 }
1075 EXPORT_SYMBOL_GPL(usb_hcd_start_port_resume);
1076 
1077 /*
1078  * usb_hcd_end_port_resume - a root-hub port has stopped sending a resume signal
1079  * @bus: the bus which the root hub belongs to
1080  * @portnum: the port which is being resumed
1081  *
1082  * HCDs should call this function when they know that a resume signal has
1083  * stopped being sent to a root-hub port.  The root hub will be allowed to
1084  * autosuspend again.
1085  *
1086  * The bus's private lock must be held by the caller.
1087  */
1088 void usb_hcd_end_port_resume(struct usb_bus *bus, int portnum)
1089 {
1090 	unsigned bit = 1 << portnum;
1091 
1092 	if (bus->resuming_ports & bit) {
1093 		bus->resuming_ports &= ~bit;
1094 		pm_runtime_put_noidle(&bus->root_hub->dev);
1095 	}
1096 }
1097 EXPORT_SYMBOL_GPL(usb_hcd_end_port_resume);
1098 
1099 /*-------------------------------------------------------------------------*/
1100 
1101 /**
1102  * usb_calc_bus_time - approximate periodic transaction time in nanoseconds
1103  * @speed: from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
1104  * @is_input: true iff the transaction sends data to the host
1105  * @isoc: true for isochronous transactions, false for interrupt ones
1106  * @bytecount: how many bytes in the transaction.
1107  *
1108  * Return: Approximate bus time in nanoseconds for a periodic transaction.
1109  *
1110  * Note:
1111  * See USB 2.0 spec section 5.11.3; only periodic transfers need to be
1112  * scheduled in software, this function is only used for such scheduling.
1113  */
1114 long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount)
1115 {
1116 	unsigned long	tmp;
1117 
1118 	switch (speed) {
1119 	case USB_SPEED_LOW: 	/* INTR only */
1120 		if (is_input) {
1121 			tmp = (67667L * (31L + 10L * BitTime (bytecount))) / 1000L;
1122 			return 64060L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp;
1123 		} else {
1124 			tmp = (66700L * (31L + 10L * BitTime (bytecount))) / 1000L;
1125 			return 64107L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp;
1126 		}
1127 	case USB_SPEED_FULL:	/* ISOC or INTR */
1128 		if (isoc) {
1129 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1130 			return ((is_input) ? 7268L : 6265L) + BW_HOST_DELAY + tmp;
1131 		} else {
1132 			tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
1133 			return 9107L + BW_HOST_DELAY + tmp;
1134 		}
1135 	case USB_SPEED_HIGH:	/* ISOC or INTR */
1136 		/* FIXME adjust for input vs output */
1137 		if (isoc)
1138 			tmp = HS_NSECS_ISO (bytecount);
1139 		else
1140 			tmp = HS_NSECS (bytecount);
1141 		return tmp;
1142 	default:
1143 		pr_debug ("%s: bogus device speed!\n", usbcore_name);
1144 		return -1;
1145 	}
1146 }
1147 EXPORT_SYMBOL_GPL(usb_calc_bus_time);
1148 
1149 
1150 /*-------------------------------------------------------------------------*/
1151 
1152 /*
1153  * Generic HC operations.
1154  */
1155 
1156 /*-------------------------------------------------------------------------*/
1157 
1158 /**
1159  * usb_hcd_link_urb_to_ep - add an URB to its endpoint queue
1160  * @hcd: host controller to which @urb was submitted
1161  * @urb: URB being submitted
1162  *
1163  * Host controller drivers should call this routine in their enqueue()
1164  * method.  The HCD's private spinlock must be held and interrupts must
1165  * be disabled.  The actions carried out here are required for URB
1166  * submission, as well as for endpoint shutdown and for usb_kill_urb.
1167  *
1168  * Return: 0 for no error, otherwise a negative error code (in which case
1169  * the enqueue() method must fail).  If no error occurs but enqueue() fails
1170  * anyway, it must call usb_hcd_unlink_urb_from_ep() before releasing
1171  * the private spinlock and returning.
1172  */
1173 int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
1174 {
1175 	int		rc = 0;
1176 
1177 	spin_lock(&hcd_urb_list_lock);
1178 
1179 	/* Check that the URB isn't being killed */
1180 	if (unlikely(atomic_read(&urb->reject))) {
1181 		rc = -EPERM;
1182 		goto done;
1183 	}
1184 
1185 	if (unlikely(!urb->ep->enabled)) {
1186 		rc = -ENOENT;
1187 		goto done;
1188 	}
1189 
1190 	if (unlikely(!urb->dev->can_submit)) {
1191 		rc = -EHOSTUNREACH;
1192 		goto done;
1193 	}
1194 
1195 	/*
1196 	 * Check the host controller's state and add the URB to the
1197 	 * endpoint's queue.
1198 	 */
1199 	if (HCD_RH_RUNNING(hcd)) {
1200 		urb->unlinked = 0;
1201 		list_add_tail(&urb->urb_list, &urb->ep->urb_list);
1202 	} else {
1203 		rc = -ESHUTDOWN;
1204 		goto done;
1205 	}
1206  done:
1207 	spin_unlock(&hcd_urb_list_lock);
1208 	return rc;
1209 }
1210 EXPORT_SYMBOL_GPL(usb_hcd_link_urb_to_ep);
1211 
1212 /**
1213  * usb_hcd_check_unlink_urb - check whether an URB may be unlinked
1214  * @hcd: host controller to which @urb was submitted
1215  * @urb: URB being checked for unlinkability
1216  * @status: error code to store in @urb if the unlink succeeds
1217  *
1218  * Host controller drivers should call this routine in their dequeue()
1219  * method.  The HCD's private spinlock must be held and interrupts must
1220  * be disabled.  The actions carried out here are required for making
1221  * sure than an unlink is valid.
1222  *
1223  * Return: 0 for no error, otherwise a negative error code (in which case
1224  * the dequeue() method must fail).  The possible error codes are:
1225  *
1226  *	-EIDRM: @urb was not submitted or has already completed.
1227  *		The completion function may not have been called yet.
1228  *
1229  *	-EBUSY: @urb has already been unlinked.
1230  */
1231 int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,
1232 		int status)
1233 {
1234 	struct list_head	*tmp;
1235 
1236 	/* insist the urb is still queued */
1237 	list_for_each(tmp, &urb->ep->urb_list) {
1238 		if (tmp == &urb->urb_list)
1239 			break;
1240 	}
1241 	if (tmp != &urb->urb_list)
1242 		return -EIDRM;
1243 
1244 	/* Any status except -EINPROGRESS means something already started to
1245 	 * unlink this URB from the hardware.  So there's no more work to do.
1246 	 */
1247 	if (urb->unlinked)
1248 		return -EBUSY;
1249 	urb->unlinked = status;
1250 	return 0;
1251 }
1252 EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb);
1253 
1254 /**
1255  * usb_hcd_unlink_urb_from_ep - remove an URB from its endpoint queue
1256  * @hcd: host controller to which @urb was submitted
1257  * @urb: URB being unlinked
1258  *
1259  * Host controller drivers should call this routine before calling
1260  * usb_hcd_giveback_urb().  The HCD's private spinlock must be held and
1261  * interrupts must be disabled.  The actions carried out here are required
1262  * for URB completion.
1263  */
1264 void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
1265 {
1266 	/* clear all state linking urb to this dev (and hcd) */
1267 	spin_lock(&hcd_urb_list_lock);
1268 	list_del_init(&urb->urb_list);
1269 	spin_unlock(&hcd_urb_list_lock);
1270 }
1271 EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);
1272 
1273 /*
1274  * Some usb host controllers can only perform dma using a small SRAM area.
1275  * The usb core itself is however optimized for host controllers that can dma
1276  * using regular system memory - like pci devices doing bus mastering.
1277  *
1278  * To support host controllers with limited dma capabilites we provide dma
1279  * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag.
1280  * For this to work properly the host controller code must first use the
1281  * function dma_declare_coherent_memory() to point out which memory area
1282  * that should be used for dma allocations.
1283  *
1284  * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for
1285  * dma using dma_alloc_coherent() which in turn allocates from the memory
1286  * area pointed out with dma_declare_coherent_memory().
1287  *
1288  * So, to summarize...
1289  *
1290  * - We need "local" memory, canonical example being
1291  *   a small SRAM on a discrete controller being the
1292  *   only memory that the controller can read ...
1293  *   (a) "normal" kernel memory is no good, and
1294  *   (b) there's not enough to share
1295  *
1296  * - The only *portable* hook for such stuff in the
1297  *   DMA framework is dma_declare_coherent_memory()
1298  *
1299  * - So we use that, even though the primary requirement
1300  *   is that the memory be "local" (hence addressible
1301  *   by that device), not "coherent".
1302  *
1303  */
1304 
1305 static int hcd_alloc_coherent(struct usb_bus *bus,
1306 			      gfp_t mem_flags, dma_addr_t *dma_handle,
1307 			      void **vaddr_handle, size_t size,
1308 			      enum dma_data_direction dir)
1309 {
1310 	unsigned char *vaddr;
1311 
1312 	if (*vaddr_handle == NULL) {
1313 		WARN_ON_ONCE(1);
1314 		return -EFAULT;
1315 	}
1316 
1317 	vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
1318 				 mem_flags, dma_handle);
1319 	if (!vaddr)
1320 		return -ENOMEM;
1321 
1322 	/*
1323 	 * Store the virtual address of the buffer at the end
1324 	 * of the allocated dma buffer. The size of the buffer
1325 	 * may be uneven so use unaligned functions instead
1326 	 * of just rounding up. It makes sense to optimize for
1327 	 * memory footprint over access speed since the amount
1328 	 * of memory available for dma may be limited.
1329 	 */
1330 	put_unaligned((unsigned long)*vaddr_handle,
1331 		      (unsigned long *)(vaddr + size));
1332 
1333 	if (dir == DMA_TO_DEVICE)
1334 		memcpy(vaddr, *vaddr_handle, size);
1335 
1336 	*vaddr_handle = vaddr;
1337 	return 0;
1338 }
1339 
1340 static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
1341 			      void **vaddr_handle, size_t size,
1342 			      enum dma_data_direction dir)
1343 {
1344 	unsigned char *vaddr = *vaddr_handle;
1345 
1346 	vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size));
1347 
1348 	if (dir == DMA_FROM_DEVICE)
1349 		memcpy(vaddr, *vaddr_handle, size);
1350 
1351 	hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle);
1352 
1353 	*vaddr_handle = vaddr;
1354 	*dma_handle = 0;
1355 }
1356 
1357 void usb_hcd_unmap_urb_setup_for_dma(struct usb_hcd *hcd, struct urb *urb)
1358 {
1359 	if (urb->transfer_flags & URB_SETUP_MAP_SINGLE)
1360 		dma_unmap_single(hcd->self.controller,
1361 				urb->setup_dma,
1362 				sizeof(struct usb_ctrlrequest),
1363 				DMA_TO_DEVICE);
1364 	else if (urb->transfer_flags & URB_SETUP_MAP_LOCAL)
1365 		hcd_free_coherent(urb->dev->bus,
1366 				&urb->setup_dma,
1367 				(void **) &urb->setup_packet,
1368 				sizeof(struct usb_ctrlrequest),
1369 				DMA_TO_DEVICE);
1370 
1371 	/* Make it safe to call this routine more than once */
1372 	urb->transfer_flags &= ~(URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL);
1373 }
1374 EXPORT_SYMBOL_GPL(usb_hcd_unmap_urb_setup_for_dma);
1375 
1376 static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
1377 {
1378 	if (hcd->driver->unmap_urb_for_dma)
1379 		hcd->driver->unmap_urb_for_dma(hcd, urb);
1380 	else
1381 		usb_hcd_unmap_urb_for_dma(hcd, urb);
1382 }
1383 
1384 void usb_hcd_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
1385 {
1386 	enum dma_data_direction dir;
1387 
1388 	usb_hcd_unmap_urb_setup_for_dma(hcd, urb);
1389 
1390 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1391 	if (urb->transfer_flags & URB_DMA_MAP_SG)
1392 		dma_unmap_sg(hcd->self.controller,
1393 				urb->sg,
1394 				urb->num_sgs,
1395 				dir);
1396 	else if (urb->transfer_flags & URB_DMA_MAP_PAGE)
1397 		dma_unmap_page(hcd->self.controller,
1398 				urb->transfer_dma,
1399 				urb->transfer_buffer_length,
1400 				dir);
1401 	else if (urb->transfer_flags & URB_DMA_MAP_SINGLE)
1402 		dma_unmap_single(hcd->self.controller,
1403 				urb->transfer_dma,
1404 				urb->transfer_buffer_length,
1405 				dir);
1406 	else if (urb->transfer_flags & URB_MAP_LOCAL)
1407 		hcd_free_coherent(urb->dev->bus,
1408 				&urb->transfer_dma,
1409 				&urb->transfer_buffer,
1410 				urb->transfer_buffer_length,
1411 				dir);
1412 
1413 	/* Make it safe to call this routine more than once */
1414 	urb->transfer_flags &= ~(URB_DMA_MAP_SG | URB_DMA_MAP_PAGE |
1415 			URB_DMA_MAP_SINGLE | URB_MAP_LOCAL);
1416 }
1417 EXPORT_SYMBOL_GPL(usb_hcd_unmap_urb_for_dma);
1418 
1419 static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
1420 			   gfp_t mem_flags)
1421 {
1422 	if (hcd->driver->map_urb_for_dma)
1423 		return hcd->driver->map_urb_for_dma(hcd, urb, mem_flags);
1424 	else
1425 		return usb_hcd_map_urb_for_dma(hcd, urb, mem_flags);
1426 }
1427 
1428 int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
1429 			    gfp_t mem_flags)
1430 {
1431 	enum dma_data_direction dir;
1432 	int ret = 0;
1433 
1434 	/* Map the URB's buffers for DMA access.
1435 	 * Lower level HCD code should use *_dma exclusively,
1436 	 * unless it uses pio or talks to another transport,
1437 	 * or uses the provided scatter gather list for bulk.
1438 	 */
1439 
1440 	if (usb_endpoint_xfer_control(&urb->ep->desc)) {
1441 		if (hcd->self.uses_pio_for_control)
1442 			return ret;
1443 		if (hcd->self.uses_dma) {
1444 			urb->setup_dma = dma_map_single(
1445 					hcd->self.controller,
1446 					urb->setup_packet,
1447 					sizeof(struct usb_ctrlrequest),
1448 					DMA_TO_DEVICE);
1449 			if (dma_mapping_error(hcd->self.controller,
1450 						urb->setup_dma))
1451 				return -EAGAIN;
1452 			urb->transfer_flags |= URB_SETUP_MAP_SINGLE;
1453 		} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
1454 			ret = hcd_alloc_coherent(
1455 					urb->dev->bus, mem_flags,
1456 					&urb->setup_dma,
1457 					(void **)&urb->setup_packet,
1458 					sizeof(struct usb_ctrlrequest),
1459 					DMA_TO_DEVICE);
1460 			if (ret)
1461 				return ret;
1462 			urb->transfer_flags |= URB_SETUP_MAP_LOCAL;
1463 		}
1464 	}
1465 
1466 	dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
1467 	if (urb->transfer_buffer_length != 0
1468 	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
1469 		if (hcd->self.uses_dma) {
1470 			if (urb->num_sgs) {
1471 				int n;
1472 
1473 				/* We don't support sg for isoc transfers ! */
1474 				if (usb_endpoint_xfer_isoc(&urb->ep->desc)) {
1475 					WARN_ON(1);
1476 					return -EINVAL;
1477 				}
1478 
1479 				n = dma_map_sg(
1480 						hcd->self.controller,
1481 						urb->sg,
1482 						urb->num_sgs,
1483 						dir);
1484 				if (n <= 0)
1485 					ret = -EAGAIN;
1486 				else
1487 					urb->transfer_flags |= URB_DMA_MAP_SG;
1488 				urb->num_mapped_sgs = n;
1489 				if (n != urb->num_sgs)
1490 					urb->transfer_flags |=
1491 							URB_DMA_SG_COMBINED;
1492 			} else if (urb->sg) {
1493 				struct scatterlist *sg = urb->sg;
1494 				urb->transfer_dma = dma_map_page(
1495 						hcd->self.controller,
1496 						sg_page(sg),
1497 						sg->offset,
1498 						urb->transfer_buffer_length,
1499 						dir);
1500 				if (dma_mapping_error(hcd->self.controller,
1501 						urb->transfer_dma))
1502 					ret = -EAGAIN;
1503 				else
1504 					urb->transfer_flags |= URB_DMA_MAP_PAGE;
1505 			} else {
1506 				urb->transfer_dma = dma_map_single(
1507 						hcd->self.controller,
1508 						urb->transfer_buffer,
1509 						urb->transfer_buffer_length,
1510 						dir);
1511 				if (dma_mapping_error(hcd->self.controller,
1512 						urb->transfer_dma))
1513 					ret = -EAGAIN;
1514 				else
1515 					urb->transfer_flags |= URB_DMA_MAP_SINGLE;
1516 			}
1517 		} else if (hcd->driver->flags & HCD_LOCAL_MEM) {
1518 			ret = hcd_alloc_coherent(
1519 					urb->dev->bus, mem_flags,
1520 					&urb->transfer_dma,
1521 					&urb->transfer_buffer,
1522 					urb->transfer_buffer_length,
1523 					dir);
1524 			if (ret == 0)
1525 				urb->transfer_flags |= URB_MAP_LOCAL;
1526 		}
1527 		if (ret && (urb->transfer_flags & (URB_SETUP_MAP_SINGLE |
1528 				URB_SETUP_MAP_LOCAL)))
1529 			usb_hcd_unmap_urb_for_dma(hcd, urb);
1530 	}
1531 	return ret;
1532 }
1533 EXPORT_SYMBOL_GPL(usb_hcd_map_urb_for_dma);
1534 
1535 /*-------------------------------------------------------------------------*/
1536 
1537 /* may be called in any context with a valid urb->dev usecount
1538  * caller surrenders "ownership" of urb
1539  * expects usb_submit_urb() to have sanity checked and conditioned all
1540  * inputs in the urb
1541  */
1542 int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
1543 {
1544 	int			status;
1545 	struct usb_hcd		*hcd = bus_to_hcd(urb->dev->bus);
1546 
1547 	/* increment urb's reference count as part of giving it to the HCD
1548 	 * (which will control it).  HCD guarantees that it either returns
1549 	 * an error or calls giveback(), but not both.
1550 	 */
1551 	usb_get_urb(urb);
1552 	atomic_inc(&urb->use_count);
1553 	atomic_inc(&urb->dev->urbnum);
1554 	usbmon_urb_submit(&hcd->self, urb);
1555 
1556 	/* NOTE requirements on root-hub callers (usbfs and the hub
1557 	 * driver, for now):  URBs' urb->transfer_buffer must be
1558 	 * valid and usb_buffer_{sync,unmap}() not be needed, since
1559 	 * they could clobber root hub response data.  Also, control
1560 	 * URBs must be submitted in process context with interrupts
1561 	 * enabled.
1562 	 */
1563 
1564 	if (is_root_hub(urb->dev)) {
1565 		status = rh_urb_enqueue(hcd, urb);
1566 	} else {
1567 		status = map_urb_for_dma(hcd, urb, mem_flags);
1568 		if (likely(status == 0)) {
1569 			status = hcd->driver->urb_enqueue(hcd, urb, mem_flags);
1570 			if (unlikely(status))
1571 				unmap_urb_for_dma(hcd, urb);
1572 		}
1573 	}
1574 
1575 	if (unlikely(status)) {
1576 		usbmon_urb_submit_error(&hcd->self, urb, status);
1577 		urb->hcpriv = NULL;
1578 		INIT_LIST_HEAD(&urb->urb_list);
1579 		atomic_dec(&urb->use_count);
1580 		atomic_dec(&urb->dev->urbnum);
1581 		if (atomic_read(&urb->reject))
1582 			wake_up(&usb_kill_urb_queue);
1583 		usb_put_urb(urb);
1584 	}
1585 	return status;
1586 }
1587 
1588 /*-------------------------------------------------------------------------*/
1589 
1590 /* this makes the hcd giveback() the urb more quickly, by kicking it
1591  * off hardware queues (which may take a while) and returning it as
1592  * soon as practical.  we've already set up the urb's return status,
1593  * but we can't know if the callback completed already.
1594  */
1595 static int unlink1(struct usb_hcd *hcd, struct urb *urb, int status)
1596 {
1597 	int		value;
1598 
1599 	if (is_root_hub(urb->dev))
1600 		value = usb_rh_urb_dequeue(hcd, urb, status);
1601 	else {
1602 
1603 		/* The only reason an HCD might fail this call is if
1604 		 * it has not yet fully queued the urb to begin with.
1605 		 * Such failures should be harmless. */
1606 		value = hcd->driver->urb_dequeue(hcd, urb, status);
1607 	}
1608 	return value;
1609 }
1610 
1611 /*
1612  * called in any context
1613  *
1614  * caller guarantees urb won't be recycled till both unlink()
1615  * and the urb's completion function return
1616  */
1617 int usb_hcd_unlink_urb (struct urb *urb, int status)
1618 {
1619 	struct usb_hcd		*hcd;
1620 	int			retval = -EIDRM;
1621 	unsigned long		flags;
1622 
1623 	/* Prevent the device and bus from going away while
1624 	 * the unlink is carried out.  If they are already gone
1625 	 * then urb->use_count must be 0, since disconnected
1626 	 * devices can't have any active URBs.
1627 	 */
1628 	spin_lock_irqsave(&hcd_urb_unlink_lock, flags);
1629 	if (atomic_read(&urb->use_count) > 0) {
1630 		retval = 0;
1631 		usb_get_dev(urb->dev);
1632 	}
1633 	spin_unlock_irqrestore(&hcd_urb_unlink_lock, flags);
1634 	if (retval == 0) {
1635 		hcd = bus_to_hcd(urb->dev->bus);
1636 		retval = unlink1(hcd, urb, status);
1637 		usb_put_dev(urb->dev);
1638 	}
1639 
1640 	if (retval == 0)
1641 		retval = -EINPROGRESS;
1642 	else if (retval != -EIDRM && retval != -EBUSY)
1643 		dev_dbg(&urb->dev->dev, "hcd_unlink_urb %p fail %d\n",
1644 				urb, retval);
1645 	return retval;
1646 }
1647 
1648 /*-------------------------------------------------------------------------*/
1649 
1650 static void __usb_hcd_giveback_urb(struct urb *urb)
1651 {
1652 	struct usb_hcd *hcd = bus_to_hcd(urb->dev->bus);
1653 	struct usb_anchor *anchor = urb->anchor;
1654 	int status = urb->unlinked;
1655 	unsigned long flags;
1656 
1657 	urb->hcpriv = NULL;
1658 	if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
1659 	    urb->actual_length < urb->transfer_buffer_length &&
1660 	    !status))
1661 		status = -EREMOTEIO;
1662 
1663 	unmap_urb_for_dma(hcd, urb);
1664 	usbmon_urb_complete(&hcd->self, urb, status);
1665 	usb_anchor_suspend_wakeups(anchor);
1666 	usb_unanchor_urb(urb);
1667 
1668 	/* pass ownership to the completion handler */
1669 	urb->status = status;
1670 
1671 	/*
1672 	 * We disable local IRQs here avoid possible deadlock because
1673 	 * drivers may call spin_lock() to hold lock which might be
1674 	 * acquired in one hard interrupt handler.
1675 	 *
1676 	 * The local_irq_save()/local_irq_restore() around complete()
1677 	 * will be removed if current USB drivers have been cleaned up
1678 	 * and no one may trigger the above deadlock situation when
1679 	 * running complete() in tasklet.
1680 	 */
1681 	local_irq_save(flags);
1682 	urb->complete(urb);
1683 	local_irq_restore(flags);
1684 
1685 	usb_anchor_resume_wakeups(anchor);
1686 	atomic_dec(&urb->use_count);
1687 	if (unlikely(atomic_read(&urb->reject)))
1688 		wake_up(&usb_kill_urb_queue);
1689 	usb_put_urb(urb);
1690 }
1691 
1692 static void usb_giveback_urb_bh(unsigned long param)
1693 {
1694 	struct giveback_urb_bh *bh = (struct giveback_urb_bh *)param;
1695 	struct list_head local_list;
1696 
1697 	spin_lock_irq(&bh->lock);
1698 	bh->running = true;
1699  restart:
1700 	list_replace_init(&bh->head, &local_list);
1701 	spin_unlock_irq(&bh->lock);
1702 
1703 	while (!list_empty(&local_list)) {
1704 		struct urb *urb;
1705 
1706 		urb = list_entry(local_list.next, struct urb, urb_list);
1707 		list_del_init(&urb->urb_list);
1708 		bh->completing_ep = urb->ep;
1709 		__usb_hcd_giveback_urb(urb);
1710 		bh->completing_ep = NULL;
1711 	}
1712 
1713 	/* check if there are new URBs to giveback */
1714 	spin_lock_irq(&bh->lock);
1715 	if (!list_empty(&bh->head))
1716 		goto restart;
1717 	bh->running = false;
1718 	spin_unlock_irq(&bh->lock);
1719 }
1720 
1721 /**
1722  * usb_hcd_giveback_urb - return URB from HCD to device driver
1723  * @hcd: host controller returning the URB
1724  * @urb: urb being returned to the USB device driver.
1725  * @status: completion status code for the URB.
1726  * Context: in_interrupt()
1727  *
1728  * This hands the URB from HCD to its USB device driver, using its
1729  * completion function.  The HCD has freed all per-urb resources
1730  * (and is done using urb->hcpriv).  It also released all HCD locks;
1731  * the device driver won't cause problems if it frees, modifies,
1732  * or resubmits this URB.
1733  *
1734  * If @urb was unlinked, the value of @status will be overridden by
1735  * @urb->unlinked.  Erroneous short transfers are detected in case
1736  * the HCD hasn't checked for them.
1737  */
1738 void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
1739 {
1740 	struct giveback_urb_bh *bh;
1741 	bool running, high_prio_bh;
1742 
1743 	/* pass status to tasklet via unlinked */
1744 	if (likely(!urb->unlinked))
1745 		urb->unlinked = status;
1746 
1747 	if (!hcd_giveback_urb_in_bh(hcd) && !is_root_hub(urb->dev)) {
1748 		__usb_hcd_giveback_urb(urb);
1749 		return;
1750 	}
1751 
1752 	if (usb_pipeisoc(urb->pipe) || usb_pipeint(urb->pipe)) {
1753 		bh = &hcd->high_prio_bh;
1754 		high_prio_bh = true;
1755 	} else {
1756 		bh = &hcd->low_prio_bh;
1757 		high_prio_bh = false;
1758 	}
1759 
1760 	spin_lock(&bh->lock);
1761 	list_add_tail(&urb->urb_list, &bh->head);
1762 	running = bh->running;
1763 	spin_unlock(&bh->lock);
1764 
1765 	if (running)
1766 		;
1767 	else if (high_prio_bh)
1768 		tasklet_hi_schedule(&bh->bh);
1769 	else
1770 		tasklet_schedule(&bh->bh);
1771 }
1772 EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb);
1773 
1774 /*-------------------------------------------------------------------------*/
1775 
1776 /* Cancel all URBs pending on this endpoint and wait for the endpoint's
1777  * queue to drain completely.  The caller must first insure that no more
1778  * URBs can be submitted for this endpoint.
1779  */
1780 void usb_hcd_flush_endpoint(struct usb_device *udev,
1781 		struct usb_host_endpoint *ep)
1782 {
1783 	struct usb_hcd		*hcd;
1784 	struct urb		*urb;
1785 
1786 	if (!ep)
1787 		return;
1788 	might_sleep();
1789 	hcd = bus_to_hcd(udev->bus);
1790 
1791 	/* No more submits can occur */
1792 	spin_lock_irq(&hcd_urb_list_lock);
1793 rescan:
1794 	list_for_each_entry (urb, &ep->urb_list, urb_list) {
1795 		int	is_in;
1796 
1797 		if (urb->unlinked)
1798 			continue;
1799 		usb_get_urb (urb);
1800 		is_in = usb_urb_dir_in(urb);
1801 		spin_unlock(&hcd_urb_list_lock);
1802 
1803 		/* kick hcd */
1804 		unlink1(hcd, urb, -ESHUTDOWN);
1805 		dev_dbg (hcd->self.controller,
1806 			"shutdown urb %p ep%d%s%s\n",
1807 			urb, usb_endpoint_num(&ep->desc),
1808 			is_in ? "in" : "out",
1809 			({	char *s;
1810 
1811 				 switch (usb_endpoint_type(&ep->desc)) {
1812 				 case USB_ENDPOINT_XFER_CONTROL:
1813 					s = ""; break;
1814 				 case USB_ENDPOINT_XFER_BULK:
1815 					s = "-bulk"; break;
1816 				 case USB_ENDPOINT_XFER_INT:
1817 					s = "-intr"; break;
1818 				 default:
1819 					s = "-iso"; break;
1820 				};
1821 				s;
1822 			}));
1823 		usb_put_urb (urb);
1824 
1825 		/* list contents may have changed */
1826 		spin_lock(&hcd_urb_list_lock);
1827 		goto rescan;
1828 	}
1829 	spin_unlock_irq(&hcd_urb_list_lock);
1830 
1831 	/* Wait until the endpoint queue is completely empty */
1832 	while (!list_empty (&ep->urb_list)) {
1833 		spin_lock_irq(&hcd_urb_list_lock);
1834 
1835 		/* The list may have changed while we acquired the spinlock */
1836 		urb = NULL;
1837 		if (!list_empty (&ep->urb_list)) {
1838 			urb = list_entry (ep->urb_list.prev, struct urb,
1839 					urb_list);
1840 			usb_get_urb (urb);
1841 		}
1842 		spin_unlock_irq(&hcd_urb_list_lock);
1843 
1844 		if (urb) {
1845 			usb_kill_urb (urb);
1846 			usb_put_urb (urb);
1847 		}
1848 	}
1849 }
1850 
1851 /**
1852  * usb_hcd_alloc_bandwidth - check whether a new bandwidth setting exceeds
1853  *				the bus bandwidth
1854  * @udev: target &usb_device
1855  * @new_config: new configuration to install
1856  * @cur_alt: the current alternate interface setting
1857  * @new_alt: alternate interface setting that is being installed
1858  *
1859  * To change configurations, pass in the new configuration in new_config,
1860  * and pass NULL for cur_alt and new_alt.
1861  *
1862  * To reset a device's configuration (put the device in the ADDRESSED state),
1863  * pass in NULL for new_config, cur_alt, and new_alt.
1864  *
1865  * To change alternate interface settings, pass in NULL for new_config,
1866  * pass in the current alternate interface setting in cur_alt,
1867  * and pass in the new alternate interface setting in new_alt.
1868  *
1869  * Return: An error if the requested bandwidth change exceeds the
1870  * bus bandwidth or host controller internal resources.
1871  */
1872 int usb_hcd_alloc_bandwidth(struct usb_device *udev,
1873 		struct usb_host_config *new_config,
1874 		struct usb_host_interface *cur_alt,
1875 		struct usb_host_interface *new_alt)
1876 {
1877 	int num_intfs, i, j;
1878 	struct usb_host_interface *alt = NULL;
1879 	int ret = 0;
1880 	struct usb_hcd *hcd;
1881 	struct usb_host_endpoint *ep;
1882 
1883 	hcd = bus_to_hcd(udev->bus);
1884 	if (!hcd->driver->check_bandwidth)
1885 		return 0;
1886 
1887 	/* Configuration is being removed - set configuration 0 */
1888 	if (!new_config && !cur_alt) {
1889 		for (i = 1; i < 16; ++i) {
1890 			ep = udev->ep_out[i];
1891 			if (ep)
1892 				hcd->driver->drop_endpoint(hcd, udev, ep);
1893 			ep = udev->ep_in[i];
1894 			if (ep)
1895 				hcd->driver->drop_endpoint(hcd, udev, ep);
1896 		}
1897 		hcd->driver->check_bandwidth(hcd, udev);
1898 		return 0;
1899 	}
1900 	/* Check if the HCD says there's enough bandwidth.  Enable all endpoints
1901 	 * each interface's alt setting 0 and ask the HCD to check the bandwidth
1902 	 * of the bus.  There will always be bandwidth for endpoint 0, so it's
1903 	 * ok to exclude it.
1904 	 */
1905 	if (new_config) {
1906 		num_intfs = new_config->desc.bNumInterfaces;
1907 		/* Remove endpoints (except endpoint 0, which is always on the
1908 		 * schedule) from the old config from the schedule
1909 		 */
1910 		for (i = 1; i < 16; ++i) {
1911 			ep = udev->ep_out[i];
1912 			if (ep) {
1913 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1914 				if (ret < 0)
1915 					goto reset;
1916 			}
1917 			ep = udev->ep_in[i];
1918 			if (ep) {
1919 				ret = hcd->driver->drop_endpoint(hcd, udev, ep);
1920 				if (ret < 0)
1921 					goto reset;
1922 			}
1923 		}
1924 		for (i = 0; i < num_intfs; ++i) {
1925 			struct usb_host_interface *first_alt;
1926 			int iface_num;
1927 
1928 			first_alt = &new_config->intf_cache[i]->altsetting[0];
1929 			iface_num = first_alt->desc.bInterfaceNumber;
1930 			/* Set up endpoints for alternate interface setting 0 */
1931 			alt = usb_find_alt_setting(new_config, iface_num, 0);
1932 			if (!alt)
1933 				/* No alt setting 0? Pick the first setting. */
1934 				alt = first_alt;
1935 
1936 			for (j = 0; j < alt->desc.bNumEndpoints; j++) {
1937 				ret = hcd->driver->add_endpoint(hcd, udev, &alt->endpoint[j]);
1938 				if (ret < 0)
1939 					goto reset;
1940 			}
1941 		}
1942 	}
1943 	if (cur_alt && new_alt) {
1944 		struct usb_interface *iface = usb_ifnum_to_if(udev,
1945 				cur_alt->desc.bInterfaceNumber);
1946 
1947 		if (!iface)
1948 			return -EINVAL;
1949 		if (iface->resetting_device) {
1950 			/*
1951 			 * The USB core just reset the device, so the xHCI host
1952 			 * and the device will think alt setting 0 is installed.
1953 			 * However, the USB core will pass in the alternate
1954 			 * setting installed before the reset as cur_alt.  Dig
1955 			 * out the alternate setting 0 structure, or the first
1956 			 * alternate setting if a broken device doesn't have alt
1957 			 * setting 0.
1958 			 */
1959 			cur_alt = usb_altnum_to_altsetting(iface, 0);
1960 			if (!cur_alt)
1961 				cur_alt = &iface->altsetting[0];
1962 		}
1963 
1964 		/* Drop all the endpoints in the current alt setting */
1965 		for (i = 0; i < cur_alt->desc.bNumEndpoints; i++) {
1966 			ret = hcd->driver->drop_endpoint(hcd, udev,
1967 					&cur_alt->endpoint[i]);
1968 			if (ret < 0)
1969 				goto reset;
1970 		}
1971 		/* Add all the endpoints in the new alt setting */
1972 		for (i = 0; i < new_alt->desc.bNumEndpoints; i++) {
1973 			ret = hcd->driver->add_endpoint(hcd, udev,
1974 					&new_alt->endpoint[i]);
1975 			if (ret < 0)
1976 				goto reset;
1977 		}
1978 	}
1979 	ret = hcd->driver->check_bandwidth(hcd, udev);
1980 reset:
1981 	if (ret < 0)
1982 		hcd->driver->reset_bandwidth(hcd, udev);
1983 	return ret;
1984 }
1985 
1986 /* Disables the endpoint: synchronizes with the hcd to make sure all
1987  * endpoint state is gone from hardware.  usb_hcd_flush_endpoint() must
1988  * have been called previously.  Use for set_configuration, set_interface,
1989  * driver removal, physical disconnect.
1990  *
1991  * example:  a qh stored in ep->hcpriv, holding state related to endpoint
1992  * type, maxpacket size, toggle, halt status, and scheduling.
1993  */
1994 void usb_hcd_disable_endpoint(struct usb_device *udev,
1995 		struct usb_host_endpoint *ep)
1996 {
1997 	struct usb_hcd		*hcd;
1998 
1999 	might_sleep();
2000 	hcd = bus_to_hcd(udev->bus);
2001 	if (hcd->driver->endpoint_disable)
2002 		hcd->driver->endpoint_disable(hcd, ep);
2003 }
2004 
2005 /**
2006  * usb_hcd_reset_endpoint - reset host endpoint state
2007  * @udev: USB device.
2008  * @ep:   the endpoint to reset.
2009  *
2010  * Resets any host endpoint state such as the toggle bit, sequence
2011  * number and current window.
2012  */
2013 void usb_hcd_reset_endpoint(struct usb_device *udev,
2014 			    struct usb_host_endpoint *ep)
2015 {
2016 	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
2017 
2018 	if (hcd->driver->endpoint_reset)
2019 		hcd->driver->endpoint_reset(hcd, ep);
2020 	else {
2021 		int epnum = usb_endpoint_num(&ep->desc);
2022 		int is_out = usb_endpoint_dir_out(&ep->desc);
2023 		int is_control = usb_endpoint_xfer_control(&ep->desc);
2024 
2025 		usb_settoggle(udev, epnum, is_out, 0);
2026 		if (is_control)
2027 			usb_settoggle(udev, epnum, !is_out, 0);
2028 	}
2029 }
2030 
2031 /**
2032  * usb_alloc_streams - allocate bulk endpoint stream IDs.
2033  * @interface:		alternate setting that includes all endpoints.
2034  * @eps:		array of endpoints that need streams.
2035  * @num_eps:		number of endpoints in the array.
2036  * @num_streams:	number of streams to allocate.
2037  * @mem_flags:		flags hcd should use to allocate memory.
2038  *
2039  * Sets up a group of bulk endpoints to have @num_streams stream IDs available.
2040  * Drivers may queue multiple transfers to different stream IDs, which may
2041  * complete in a different order than they were queued.
2042  *
2043  * Return: On success, the number of allocated streams. On failure, a negative
2044  * error code.
2045  */
2046 int usb_alloc_streams(struct usb_interface *interface,
2047 		struct usb_host_endpoint **eps, unsigned int num_eps,
2048 		unsigned int num_streams, gfp_t mem_flags)
2049 {
2050 	struct usb_hcd *hcd;
2051 	struct usb_device *dev;
2052 	int i;
2053 
2054 	dev = interface_to_usbdev(interface);
2055 	hcd = bus_to_hcd(dev->bus);
2056 	if (!hcd->driver->alloc_streams || !hcd->driver->free_streams)
2057 		return -EINVAL;
2058 	if (dev->speed != USB_SPEED_SUPER)
2059 		return -EINVAL;
2060 
2061 	/* Streams only apply to bulk endpoints. */
2062 	for (i = 0; i < num_eps; i++)
2063 		if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
2064 			return -EINVAL;
2065 
2066 	return hcd->driver->alloc_streams(hcd, dev, eps, num_eps,
2067 			num_streams, mem_flags);
2068 }
2069 EXPORT_SYMBOL_GPL(usb_alloc_streams);
2070 
2071 /**
2072  * usb_free_streams - free bulk endpoint stream IDs.
2073  * @interface:	alternate setting that includes all endpoints.
2074  * @eps:	array of endpoints to remove streams from.
2075  * @num_eps:	number of endpoints in the array.
2076  * @mem_flags:	flags hcd should use to allocate memory.
2077  *
2078  * Reverts a group of bulk endpoints back to not using stream IDs.
2079  * Can fail if we are given bad arguments, or HCD is broken.
2080  *
2081  * Return: On success, the number of allocated streams. On failure, a negative
2082  * error code.
2083  */
2084 int usb_free_streams(struct usb_interface *interface,
2085 		struct usb_host_endpoint **eps, unsigned int num_eps,
2086 		gfp_t mem_flags)
2087 {
2088 	struct usb_hcd *hcd;
2089 	struct usb_device *dev;
2090 	int i;
2091 
2092 	dev = interface_to_usbdev(interface);
2093 	hcd = bus_to_hcd(dev->bus);
2094 	if (dev->speed != USB_SPEED_SUPER)
2095 		return -EINVAL;
2096 
2097 	/* Streams only apply to bulk endpoints. */
2098 	for (i = 0; i < num_eps; i++)
2099 		if (!eps[i] || !usb_endpoint_xfer_bulk(&eps[i]->desc))
2100 			return -EINVAL;
2101 
2102 	return hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
2103 }
2104 EXPORT_SYMBOL_GPL(usb_free_streams);
2105 
2106 /* Protect against drivers that try to unlink URBs after the device
2107  * is gone, by waiting until all unlinks for @udev are finished.
2108  * Since we don't currently track URBs by device, simply wait until
2109  * nothing is running in the locked region of usb_hcd_unlink_urb().
2110  */
2111 void usb_hcd_synchronize_unlinks(struct usb_device *udev)
2112 {
2113 	spin_lock_irq(&hcd_urb_unlink_lock);
2114 	spin_unlock_irq(&hcd_urb_unlink_lock);
2115 }
2116 
2117 /*-------------------------------------------------------------------------*/
2118 
2119 /* called in any context */
2120 int usb_hcd_get_frame_number (struct usb_device *udev)
2121 {
2122 	struct usb_hcd	*hcd = bus_to_hcd(udev->bus);
2123 
2124 	if (!HCD_RH_RUNNING(hcd))
2125 		return -ESHUTDOWN;
2126 	return hcd->driver->get_frame_number (hcd);
2127 }
2128 
2129 /*-------------------------------------------------------------------------*/
2130 
2131 #ifdef	CONFIG_PM
2132 
2133 int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg)
2134 {
2135 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
2136 	int		status;
2137 	int		old_state = hcd->state;
2138 
2139 	dev_dbg(&rhdev->dev, "bus %ssuspend, wakeup %d\n",
2140 			(PMSG_IS_AUTO(msg) ? "auto-" : ""),
2141 			rhdev->do_remote_wakeup);
2142 	if (HCD_DEAD(hcd)) {
2143 		dev_dbg(&rhdev->dev, "skipped %s of dead bus\n", "suspend");
2144 		return 0;
2145 	}
2146 
2147 	if (!hcd->driver->bus_suspend) {
2148 		status = -ENOENT;
2149 	} else {
2150 		clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2151 		hcd->state = HC_STATE_QUIESCING;
2152 		status = hcd->driver->bus_suspend(hcd);
2153 	}
2154 	if (status == 0) {
2155 		usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
2156 		hcd->state = HC_STATE_SUSPENDED;
2157 
2158 		/* Did we race with a root-hub wakeup event? */
2159 		if (rhdev->do_remote_wakeup) {
2160 			char	buffer[6];
2161 
2162 			status = hcd->driver->hub_status_data(hcd, buffer);
2163 			if (status != 0) {
2164 				dev_dbg(&rhdev->dev, "suspend raced with wakeup event\n");
2165 				hcd_bus_resume(rhdev, PMSG_AUTO_RESUME);
2166 				status = -EBUSY;
2167 			}
2168 		}
2169 	} else {
2170 		spin_lock_irq(&hcd_root_hub_lock);
2171 		if (!HCD_DEAD(hcd)) {
2172 			set_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2173 			hcd->state = old_state;
2174 		}
2175 		spin_unlock_irq(&hcd_root_hub_lock);
2176 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
2177 				"suspend", status);
2178 	}
2179 	return status;
2180 }
2181 
2182 int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
2183 {
2184 	struct usb_hcd	*hcd = container_of(rhdev->bus, struct usb_hcd, self);
2185 	int		status;
2186 	int		old_state = hcd->state;
2187 
2188 	dev_dbg(&rhdev->dev, "usb %sresume\n",
2189 			(PMSG_IS_AUTO(msg) ? "auto-" : ""));
2190 	if (HCD_DEAD(hcd)) {
2191 		dev_dbg(&rhdev->dev, "skipped %s of dead bus\n", "resume");
2192 		return 0;
2193 	}
2194 	if (!hcd->driver->bus_resume)
2195 		return -ENOENT;
2196 	if (HCD_RH_RUNNING(hcd))
2197 		return 0;
2198 
2199 	hcd->state = HC_STATE_RESUMING;
2200 	status = hcd->driver->bus_resume(hcd);
2201 	clear_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
2202 	if (status == 0) {
2203 		struct usb_device *udev;
2204 		int port1;
2205 
2206 		spin_lock_irq(&hcd_root_hub_lock);
2207 		if (!HCD_DEAD(hcd)) {
2208 			usb_set_device_state(rhdev, rhdev->actconfig
2209 					? USB_STATE_CONFIGURED
2210 					: USB_STATE_ADDRESS);
2211 			set_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2212 			hcd->state = HC_STATE_RUNNING;
2213 		}
2214 		spin_unlock_irq(&hcd_root_hub_lock);
2215 
2216 		/*
2217 		 * Check whether any of the enabled ports on the root hub are
2218 		 * unsuspended.  If they are then a TRSMRCY delay is needed
2219 		 * (this is what the USB-2 spec calls a "global resume").
2220 		 * Otherwise we can skip the delay.
2221 		 */
2222 		usb_hub_for_each_child(rhdev, port1, udev) {
2223 			if (udev->state != USB_STATE_NOTATTACHED &&
2224 					!udev->port_is_suspended) {
2225 				usleep_range(10000, 11000);	/* TRSMRCY */
2226 				break;
2227 			}
2228 		}
2229 	} else {
2230 		hcd->state = old_state;
2231 		dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
2232 				"resume", status);
2233 		if (status != -ESHUTDOWN)
2234 			usb_hc_died(hcd);
2235 	}
2236 	return status;
2237 }
2238 
2239 #endif	/* CONFIG_PM */
2240 
2241 #ifdef	CONFIG_PM_RUNTIME
2242 
2243 /* Workqueue routine for root-hub remote wakeup */
2244 static void hcd_resume_work(struct work_struct *work)
2245 {
2246 	struct usb_hcd *hcd = container_of(work, struct usb_hcd, wakeup_work);
2247 	struct usb_device *udev = hcd->self.root_hub;
2248 
2249 	usb_lock_device(udev);
2250 	usb_remote_wakeup(udev);
2251 	usb_unlock_device(udev);
2252 }
2253 
2254 /**
2255  * usb_hcd_resume_root_hub - called by HCD to resume its root hub
2256  * @hcd: host controller for this root hub
2257  *
2258  * The USB host controller calls this function when its root hub is
2259  * suspended (with the remote wakeup feature enabled) and a remote
2260  * wakeup request is received.  The routine submits a workqueue request
2261  * to resume the root hub (that is, manage its downstream ports again).
2262  */
2263 void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
2264 {
2265 	unsigned long flags;
2266 
2267 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
2268 	if (hcd->rh_registered) {
2269 		set_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
2270 		queue_work(pm_wq, &hcd->wakeup_work);
2271 	}
2272 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
2273 }
2274 EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hub);
2275 
2276 #endif	/* CONFIG_PM_RUNTIME */
2277 
2278 /*-------------------------------------------------------------------------*/
2279 
2280 #ifdef	CONFIG_USB_OTG
2281 
2282 /**
2283  * usb_bus_start_enum - start immediate enumeration (for OTG)
2284  * @bus: the bus (must use hcd framework)
2285  * @port_num: 1-based number of port; usually bus->otg_port
2286  * Context: in_interrupt()
2287  *
2288  * Starts enumeration, with an immediate reset followed later by
2289  * khubd identifying and possibly configuring the device.
2290  * This is needed by OTG controller drivers, where it helps meet
2291  * HNP protocol timing requirements for starting a port reset.
2292  *
2293  * Return: 0 if successful.
2294  */
2295 int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num)
2296 {
2297 	struct usb_hcd		*hcd;
2298 	int			status = -EOPNOTSUPP;
2299 
2300 	/* NOTE: since HNP can't start by grabbing the bus's address0_sem,
2301 	 * boards with root hubs hooked up to internal devices (instead of
2302 	 * just the OTG port) may need more attention to resetting...
2303 	 */
2304 	hcd = container_of (bus, struct usb_hcd, self);
2305 	if (port_num && hcd->driver->start_port_reset)
2306 		status = hcd->driver->start_port_reset(hcd, port_num);
2307 
2308 	/* run khubd shortly after (first) root port reset finishes;
2309 	 * it may issue others, until at least 50 msecs have passed.
2310 	 */
2311 	if (status == 0)
2312 		mod_timer(&hcd->rh_timer, jiffies + msecs_to_jiffies(10));
2313 	return status;
2314 }
2315 EXPORT_SYMBOL_GPL(usb_bus_start_enum);
2316 
2317 #endif
2318 
2319 /*-------------------------------------------------------------------------*/
2320 
2321 /**
2322  * usb_hcd_irq - hook IRQs to HCD framework (bus glue)
2323  * @irq: the IRQ being raised
2324  * @__hcd: pointer to the HCD whose IRQ is being signaled
2325  *
2326  * If the controller isn't HALTed, calls the driver's irq handler.
2327  * Checks whether the controller is now dead.
2328  *
2329  * Return: %IRQ_HANDLED if the IRQ was handled. %IRQ_NONE otherwise.
2330  */
2331 irqreturn_t usb_hcd_irq (int irq, void *__hcd)
2332 {
2333 	struct usb_hcd		*hcd = __hcd;
2334 	irqreturn_t		rc;
2335 
2336 	if (unlikely(HCD_DEAD(hcd) || !HCD_HW_ACCESSIBLE(hcd)))
2337 		rc = IRQ_NONE;
2338 	else if (hcd->driver->irq(hcd) == IRQ_NONE)
2339 		rc = IRQ_NONE;
2340 	else
2341 		rc = IRQ_HANDLED;
2342 
2343 	return rc;
2344 }
2345 EXPORT_SYMBOL_GPL(usb_hcd_irq);
2346 
2347 /*-------------------------------------------------------------------------*/
2348 
2349 /**
2350  * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
2351  * @hcd: pointer to the HCD representing the controller
2352  *
2353  * This is called by bus glue to report a USB host controller that died
2354  * while operations may still have been pending.  It's called automatically
2355  * by the PCI glue, so only glue for non-PCI busses should need to call it.
2356  *
2357  * Only call this function with the primary HCD.
2358  */
2359 void usb_hc_died (struct usb_hcd *hcd)
2360 {
2361 	unsigned long flags;
2362 
2363 	dev_err (hcd->self.controller, "HC died; cleaning up\n");
2364 
2365 	spin_lock_irqsave (&hcd_root_hub_lock, flags);
2366 	clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2367 	set_bit(HCD_FLAG_DEAD, &hcd->flags);
2368 	if (hcd->rh_registered) {
2369 		clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2370 
2371 		/* make khubd clean up old urbs and devices */
2372 		usb_set_device_state (hcd->self.root_hub,
2373 				USB_STATE_NOTATTACHED);
2374 		usb_kick_khubd (hcd->self.root_hub);
2375 	}
2376 	if (usb_hcd_is_primary_hcd(hcd) && hcd->shared_hcd) {
2377 		hcd = hcd->shared_hcd;
2378 		if (hcd->rh_registered) {
2379 			clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2380 
2381 			/* make khubd clean up old urbs and devices */
2382 			usb_set_device_state(hcd->self.root_hub,
2383 					USB_STATE_NOTATTACHED);
2384 			usb_kick_khubd(hcd->self.root_hub);
2385 		}
2386 	}
2387 	spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
2388 	/* Make sure that the other roothub is also deallocated. */
2389 }
2390 EXPORT_SYMBOL_GPL (usb_hc_died);
2391 
2392 /*-------------------------------------------------------------------------*/
2393 
2394 static void init_giveback_urb_bh(struct giveback_urb_bh *bh)
2395 {
2396 
2397 	spin_lock_init(&bh->lock);
2398 	INIT_LIST_HEAD(&bh->head);
2399 	tasklet_init(&bh->bh, usb_giveback_urb_bh, (unsigned long)bh);
2400 }
2401 
2402 /**
2403  * usb_create_shared_hcd - create and initialize an HCD structure
2404  * @driver: HC driver that will use this hcd
2405  * @dev: device for this HC, stored in hcd->self.controller
2406  * @bus_name: value to store in hcd->self.bus_name
2407  * @primary_hcd: a pointer to the usb_hcd structure that is sharing the
2408  *              PCI device.  Only allocate certain resources for the primary HCD
2409  * Context: !in_interrupt()
2410  *
2411  * Allocate a struct usb_hcd, with extra space at the end for the
2412  * HC driver's private data.  Initialize the generic members of the
2413  * hcd structure.
2414  *
2415  * Return: On success, a pointer to the created and initialized HCD structure.
2416  * On failure (e.g. if memory is unavailable), %NULL.
2417  */
2418 struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver,
2419 		struct device *dev, const char *bus_name,
2420 		struct usb_hcd *primary_hcd)
2421 {
2422 	struct usb_hcd *hcd;
2423 
2424 	hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
2425 	if (!hcd) {
2426 		dev_dbg (dev, "hcd alloc failed\n");
2427 		return NULL;
2428 	}
2429 	if (primary_hcd == NULL) {
2430 		hcd->bandwidth_mutex = kmalloc(sizeof(*hcd->bandwidth_mutex),
2431 				GFP_KERNEL);
2432 		if (!hcd->bandwidth_mutex) {
2433 			kfree(hcd);
2434 			dev_dbg(dev, "hcd bandwidth mutex alloc failed\n");
2435 			return NULL;
2436 		}
2437 		mutex_init(hcd->bandwidth_mutex);
2438 		dev_set_drvdata(dev, hcd);
2439 	} else {
2440 		hcd->bandwidth_mutex = primary_hcd->bandwidth_mutex;
2441 		hcd->primary_hcd = primary_hcd;
2442 		primary_hcd->primary_hcd = primary_hcd;
2443 		hcd->shared_hcd = primary_hcd;
2444 		primary_hcd->shared_hcd = hcd;
2445 	}
2446 
2447 	kref_init(&hcd->kref);
2448 
2449 	usb_bus_init(&hcd->self);
2450 	hcd->self.controller = dev;
2451 	hcd->self.bus_name = bus_name;
2452 	hcd->self.uses_dma = (dev->dma_mask != NULL);
2453 
2454 	init_timer(&hcd->rh_timer);
2455 	hcd->rh_timer.function = rh_timer_func;
2456 	hcd->rh_timer.data = (unsigned long) hcd;
2457 #ifdef CONFIG_PM_RUNTIME
2458 	INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
2459 #endif
2460 
2461 	hcd->driver = driver;
2462 	hcd->speed = driver->flags & HCD_MASK;
2463 	hcd->product_desc = (driver->product_desc) ? driver->product_desc :
2464 			"USB Host Controller";
2465 	return hcd;
2466 }
2467 EXPORT_SYMBOL_GPL(usb_create_shared_hcd);
2468 
2469 /**
2470  * usb_create_hcd - create and initialize an HCD structure
2471  * @driver: HC driver that will use this hcd
2472  * @dev: device for this HC, stored in hcd->self.controller
2473  * @bus_name: value to store in hcd->self.bus_name
2474  * Context: !in_interrupt()
2475  *
2476  * Allocate a struct usb_hcd, with extra space at the end for the
2477  * HC driver's private data.  Initialize the generic members of the
2478  * hcd structure.
2479  *
2480  * Return: On success, a pointer to the created and initialized HCD
2481  * structure. On failure (e.g. if memory is unavailable), %NULL.
2482  */
2483 struct usb_hcd *usb_create_hcd(const struct hc_driver *driver,
2484 		struct device *dev, const char *bus_name)
2485 {
2486 	return usb_create_shared_hcd(driver, dev, bus_name, NULL);
2487 }
2488 EXPORT_SYMBOL_GPL(usb_create_hcd);
2489 
2490 /*
2491  * Roothubs that share one PCI device must also share the bandwidth mutex.
2492  * Don't deallocate the bandwidth_mutex until the last shared usb_hcd is
2493  * deallocated.
2494  *
2495  * Make sure to only deallocate the bandwidth_mutex when the primary HCD is
2496  * freed.  When hcd_release() is called for the non-primary HCD, set the
2497  * primary_hcd's shared_hcd pointer to null (since the non-primary HCD will be
2498  * freed shortly).
2499  */
2500 static void hcd_release (struct kref *kref)
2501 {
2502 	struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);
2503 
2504 	if (usb_hcd_is_primary_hcd(hcd))
2505 		kfree(hcd->bandwidth_mutex);
2506 	else
2507 		hcd->shared_hcd->shared_hcd = NULL;
2508 	kfree(hcd);
2509 }
2510 
2511 struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd)
2512 {
2513 	if (hcd)
2514 		kref_get (&hcd->kref);
2515 	return hcd;
2516 }
2517 EXPORT_SYMBOL_GPL(usb_get_hcd);
2518 
2519 void usb_put_hcd (struct usb_hcd *hcd)
2520 {
2521 	if (hcd)
2522 		kref_put (&hcd->kref, hcd_release);
2523 }
2524 EXPORT_SYMBOL_GPL(usb_put_hcd);
2525 
2526 int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
2527 {
2528 	if (!hcd->primary_hcd)
2529 		return 1;
2530 	return hcd == hcd->primary_hcd;
2531 }
2532 EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
2533 
2534 int usb_hcd_find_raw_port_number(struct usb_hcd *hcd, int port1)
2535 {
2536 	if (!hcd->driver->find_raw_port_number)
2537 		return port1;
2538 
2539 	return hcd->driver->find_raw_port_number(hcd, port1);
2540 }
2541 
2542 static int usb_hcd_request_irqs(struct usb_hcd *hcd,
2543 		unsigned int irqnum, unsigned long irqflags)
2544 {
2545 	int retval;
2546 
2547 	if (hcd->driver->irq) {
2548 
2549 		snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
2550 				hcd->driver->description, hcd->self.busnum);
2551 		retval = request_irq(irqnum, &usb_hcd_irq, irqflags,
2552 				hcd->irq_descr, hcd);
2553 		if (retval != 0) {
2554 			dev_err(hcd->self.controller,
2555 					"request interrupt %d failed\n",
2556 					irqnum);
2557 			return retval;
2558 		}
2559 		hcd->irq = irqnum;
2560 		dev_info(hcd->self.controller, "irq %d, %s 0x%08llx\n", irqnum,
2561 				(hcd->driver->flags & HCD_MEMORY) ?
2562 					"io mem" : "io base",
2563 					(unsigned long long)hcd->rsrc_start);
2564 	} else {
2565 		hcd->irq = 0;
2566 		if (hcd->rsrc_start)
2567 			dev_info(hcd->self.controller, "%s 0x%08llx\n",
2568 					(hcd->driver->flags & HCD_MEMORY) ?
2569 					"io mem" : "io base",
2570 					(unsigned long long)hcd->rsrc_start);
2571 	}
2572 	return 0;
2573 }
2574 
2575 /**
2576  * usb_add_hcd - finish generic HCD structure initialization and register
2577  * @hcd: the usb_hcd structure to initialize
2578  * @irqnum: Interrupt line to allocate
2579  * @irqflags: Interrupt type flags
2580  *
2581  * Finish the remaining parts of generic HCD initialization: allocate the
2582  * buffers of consistent memory, register the bus, request the IRQ line,
2583  * and call the driver's reset() and start() routines.
2584  */
2585 int usb_add_hcd(struct usb_hcd *hcd,
2586 		unsigned int irqnum, unsigned long irqflags)
2587 {
2588 	int retval;
2589 	struct usb_device *rhdev;
2590 
2591 	dev_info(hcd->self.controller, "%s\n", hcd->product_desc);
2592 
2593 	/* Keep old behaviour if authorized_default is not in [0, 1]. */
2594 	if (authorized_default < 0 || authorized_default > 1)
2595 		hcd->authorized_default = hcd->wireless ? 0 : 1;
2596 	else
2597 		hcd->authorized_default = authorized_default;
2598 	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
2599 
2600 	/* HC is in reset state, but accessible.  Now do the one-time init,
2601 	 * bottom up so that hcds can customize the root hubs before khubd
2602 	 * starts talking to them.  (Note, bus id is assigned early too.)
2603 	 */
2604 	if ((retval = hcd_buffer_create(hcd)) != 0) {
2605 		dev_dbg(hcd->self.controller, "pool alloc failed\n");
2606 		return retval;
2607 	}
2608 
2609 	if ((retval = usb_register_bus(&hcd->self)) < 0)
2610 		goto err_register_bus;
2611 
2612 	if ((rhdev = usb_alloc_dev(NULL, &hcd->self, 0)) == NULL) {
2613 		dev_err(hcd->self.controller, "unable to allocate root hub\n");
2614 		retval = -ENOMEM;
2615 		goto err_allocate_root_hub;
2616 	}
2617 	hcd->self.root_hub = rhdev;
2618 
2619 	switch (hcd->speed) {
2620 	case HCD_USB11:
2621 		rhdev->speed = USB_SPEED_FULL;
2622 		break;
2623 	case HCD_USB2:
2624 		rhdev->speed = USB_SPEED_HIGH;
2625 		break;
2626 	case HCD_USB25:
2627 		rhdev->speed = USB_SPEED_WIRELESS;
2628 		break;
2629 	case HCD_USB3:
2630 		rhdev->speed = USB_SPEED_SUPER;
2631 		break;
2632 	default:
2633 		retval = -EINVAL;
2634 		goto err_set_rh_speed;
2635 	}
2636 
2637 	/* wakeup flag init defaults to "everything works" for root hubs,
2638 	 * but drivers can override it in reset() if needed, along with
2639 	 * recording the overall controller's system wakeup capability.
2640 	 */
2641 	device_set_wakeup_capable(&rhdev->dev, 1);
2642 
2643 	/* HCD_FLAG_RH_RUNNING doesn't matter until the root hub is
2644 	 * registered.  But since the controller can die at any time,
2645 	 * let's initialize the flag before touching the hardware.
2646 	 */
2647 	set_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2648 
2649 	/* "reset" is misnamed; its role is now one-time init. the controller
2650 	 * should already have been reset (and boot firmware kicked off etc).
2651 	 */
2652 	if (hcd->driver->reset && (retval = hcd->driver->reset(hcd)) < 0) {
2653 		dev_err(hcd->self.controller, "can't setup: %d\n", retval);
2654 		goto err_hcd_driver_setup;
2655 	}
2656 	hcd->rh_pollable = 1;
2657 
2658 	/* NOTE: root hub and controller capabilities may not be the same */
2659 	if (device_can_wakeup(hcd->self.controller)
2660 			&& device_can_wakeup(&hcd->self.root_hub->dev))
2661 		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
2662 
2663 	/* initialize tasklets */
2664 	init_giveback_urb_bh(&hcd->high_prio_bh);
2665 	init_giveback_urb_bh(&hcd->low_prio_bh);
2666 
2667 	/* enable irqs just before we start the controller,
2668 	 * if the BIOS provides legacy PCI irqs.
2669 	 */
2670 	if (usb_hcd_is_primary_hcd(hcd) && irqnum) {
2671 		retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
2672 		if (retval)
2673 			goto err_request_irq;
2674 	}
2675 
2676 	hcd->state = HC_STATE_RUNNING;
2677 	retval = hcd->driver->start(hcd);
2678 	if (retval < 0) {
2679 		dev_err(hcd->self.controller, "startup error %d\n", retval);
2680 		goto err_hcd_driver_start;
2681 	}
2682 
2683 	/* starting here, usbcore will pay attention to this root hub */
2684 	if ((retval = register_root_hub(hcd)) != 0)
2685 		goto err_register_root_hub;
2686 
2687 	retval = sysfs_create_group(&rhdev->dev.kobj, &usb_bus_attr_group);
2688 	if (retval < 0) {
2689 		printk(KERN_ERR "Cannot register USB bus sysfs attributes: %d\n",
2690 		       retval);
2691 		goto error_create_attr_group;
2692 	}
2693 	if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
2694 		usb_hcd_poll_rh_status(hcd);
2695 
2696 	/*
2697 	 * Host controllers don't generate their own wakeup requests;
2698 	 * they only forward requests from the root hub.  Therefore
2699 	 * controllers should always be enabled for remote wakeup.
2700 	 */
2701 	device_wakeup_enable(hcd->self.controller);
2702 	return retval;
2703 
2704 error_create_attr_group:
2705 	clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2706 	if (HC_IS_RUNNING(hcd->state))
2707 		hcd->state = HC_STATE_QUIESCING;
2708 	spin_lock_irq(&hcd_root_hub_lock);
2709 	hcd->rh_registered = 0;
2710 	spin_unlock_irq(&hcd_root_hub_lock);
2711 
2712 #ifdef CONFIG_PM_RUNTIME
2713 	cancel_work_sync(&hcd->wakeup_work);
2714 #endif
2715 	mutex_lock(&usb_bus_list_lock);
2716 	usb_disconnect(&rhdev);		/* Sets rhdev to NULL */
2717 	mutex_unlock(&usb_bus_list_lock);
2718 err_register_root_hub:
2719 	hcd->rh_pollable = 0;
2720 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2721 	del_timer_sync(&hcd->rh_timer);
2722 	hcd->driver->stop(hcd);
2723 	hcd->state = HC_STATE_HALT;
2724 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2725 	del_timer_sync(&hcd->rh_timer);
2726 err_hcd_driver_start:
2727 	if (usb_hcd_is_primary_hcd(hcd) && hcd->irq > 0)
2728 		free_irq(irqnum, hcd);
2729 err_request_irq:
2730 err_hcd_driver_setup:
2731 err_set_rh_speed:
2732 	usb_put_dev(hcd->self.root_hub);
2733 err_allocate_root_hub:
2734 	usb_deregister_bus(&hcd->self);
2735 err_register_bus:
2736 	hcd_buffer_destroy(hcd);
2737 	return retval;
2738 }
2739 EXPORT_SYMBOL_GPL(usb_add_hcd);
2740 
2741 /**
2742  * usb_remove_hcd - shutdown processing for generic HCDs
2743  * @hcd: the usb_hcd structure to remove
2744  * Context: !in_interrupt()
2745  *
2746  * Disconnects the root hub, then reverses the effects of usb_add_hcd(),
2747  * invoking the HCD's stop() method.
2748  */
2749 void usb_remove_hcd(struct usb_hcd *hcd)
2750 {
2751 	struct usb_device *rhdev = hcd->self.root_hub;
2752 
2753 	dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);
2754 
2755 	usb_get_dev(rhdev);
2756 	sysfs_remove_group(&rhdev->dev.kobj, &usb_bus_attr_group);
2757 
2758 	clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
2759 	if (HC_IS_RUNNING (hcd->state))
2760 		hcd->state = HC_STATE_QUIESCING;
2761 
2762 	dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
2763 	spin_lock_irq (&hcd_root_hub_lock);
2764 	hcd->rh_registered = 0;
2765 	spin_unlock_irq (&hcd_root_hub_lock);
2766 
2767 #ifdef CONFIG_PM_RUNTIME
2768 	cancel_work_sync(&hcd->wakeup_work);
2769 #endif
2770 
2771 	mutex_lock(&usb_bus_list_lock);
2772 	usb_disconnect(&rhdev);		/* Sets rhdev to NULL */
2773 	mutex_unlock(&usb_bus_list_lock);
2774 
2775 	/*
2776 	 * tasklet_kill() isn't needed here because:
2777 	 * - driver's disconnect() called from usb_disconnect() should
2778 	 *   make sure its URBs are completed during the disconnect()
2779 	 *   callback
2780 	 *
2781 	 * - it is too late to run complete() here since driver may have
2782 	 *   been removed already now
2783 	 */
2784 
2785 	/* Prevent any more root-hub status calls from the timer.
2786 	 * The HCD might still restart the timer (if a port status change
2787 	 * interrupt occurs), but usb_hcd_poll_rh_status() won't invoke
2788 	 * the hub_status_data() callback.
2789 	 */
2790 	hcd->rh_pollable = 0;
2791 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2792 	del_timer_sync(&hcd->rh_timer);
2793 
2794 	hcd->driver->stop(hcd);
2795 	hcd->state = HC_STATE_HALT;
2796 
2797 	/* In case the HCD restarted the timer, stop it again. */
2798 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
2799 	del_timer_sync(&hcd->rh_timer);
2800 
2801 	if (usb_hcd_is_primary_hcd(hcd)) {
2802 		if (hcd->irq > 0)
2803 			free_irq(hcd->irq, hcd);
2804 	}
2805 
2806 	usb_put_dev(hcd->self.root_hub);
2807 	usb_deregister_bus(&hcd->self);
2808 	hcd_buffer_destroy(hcd);
2809 }
2810 EXPORT_SYMBOL_GPL(usb_remove_hcd);
2811 
2812 void
2813 usb_hcd_platform_shutdown(struct platform_device *dev)
2814 {
2815 	struct usb_hcd *hcd = platform_get_drvdata(dev);
2816 
2817 	if (hcd->driver->shutdown)
2818 		hcd->driver->shutdown(hcd);
2819 }
2820 EXPORT_SYMBOL_GPL(usb_hcd_platform_shutdown);
2821 
2822 /*-------------------------------------------------------------------------*/
2823 
2824 #if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)
2825 
2826 struct usb_mon_operations *mon_ops;
2827 
2828 /*
2829  * The registration is unlocked.
2830  * We do it this way because we do not want to lock in hot paths.
2831  *
2832  * Notice that the code is minimally error-proof. Because usbmon needs
2833  * symbols from usbcore, usbcore gets referenced and cannot be unloaded first.
2834  */
2835 
2836 int usb_mon_register (struct usb_mon_operations *ops)
2837 {
2838 
2839 	if (mon_ops)
2840 		return -EBUSY;
2841 
2842 	mon_ops = ops;
2843 	mb();
2844 	return 0;
2845 }
2846 EXPORT_SYMBOL_GPL (usb_mon_register);
2847 
2848 void usb_mon_deregister (void)
2849 {
2850 
2851 	if (mon_ops == NULL) {
2852 		printk(KERN_ERR "USB: monitor was not registered\n");
2853 		return;
2854 	}
2855 	mon_ops = NULL;
2856 	mb();
2857 }
2858 EXPORT_SYMBOL_GPL (usb_mon_deregister);
2859 
2860 #endif /* CONFIG_USB_MON || CONFIG_USB_MON_MODULE */
2861