5b5a2e348ecb86c434f59ccbf32d6797a73e3758
[pandora-kernel.git] / drivers / staging / usbip / vhci_hcd.c
1 /*
2  * Copyright (C) 2003-2008 Takahiro Hirofuchi
3  *
4  * This is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
17  * USA.
18  */
19
20
21 #include "usbip_common.h"
22 #include "vhci.h"
23
24 #define DRIVER_VERSION "1.0"
25 #define DRIVER_AUTHOR "Takahiro Hirofuchi"
26 #define DRIVER_DESC "Virtual Host Controller Interface Driver for USB/IP"
27 #define DRIVER_LICENCE "GPL"
28 MODULE_AUTHOR(DRIVER_AUTHOR);
29 MODULE_DESCRIPTION(DRIVER_DESC);
30 MODULE_LICENSE(DRIVER_LICENCE);
31
32
33
34 /*
35  * TODO
36  *      - update root hub emulation
37  *      - move the emulation code to userland ?
38  *              porting to other operating systems
39  *              minimize kernel code
40  *      - add suspend/resume code
41  *      - clean up everything
42  */
43
44
45 /* See usb gadget dummy hcd */
46
47
48 static int vhci_hub_status(struct usb_hcd *hcd, char *buff);
49 static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
50                 u16 wIndex, char *buff, u16 wLength);
51 static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
52                                                         gfp_t mem_flags);
53 static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status);
54 static int vhci_start(struct usb_hcd *vhci_hcd);
55 static void vhci_stop(struct usb_hcd *hcd);
56 static int vhci_get_frame_number(struct usb_hcd *hcd);
57
58 static const char driver_name[] = "vhci_hcd";
59 static const char driver_desc[] = "USB/IP Virtual Host Contoroller";
60
61 struct vhci_hcd *the_controller;
62
63 static const char *bit_desc[] = {
64         "CONNECTION",           /*0*/
65         "ENABLE",               /*1*/
66         "SUSPEND",              /*2*/
67         "OVER_CURRENT",         /*3*/
68         "RESET",                /*4*/
69         "R5",           /*5*/
70         "R6",           /*6*/
71         "R7",           /*7*/
72         "POWER",                /*8*/
73         "LOWSPEED",             /*9*/
74         "HIGHSPEED",            /*10*/
75         "PORT_TEST",            /*11*/
76         "INDICATOR",            /*12*/
77         "R13",          /*13*/
78         "R14",          /*14*/
79         "R15",          /*15*/
80         "C_CONNECTION",         /*16*/
81         "C_ENABLE",             /*17*/
82         "C_SUSPEND",            /*18*/
83         "C_OVER_CURRENT",       /*19*/
84         "C_RESET",              /*20*/
85         "R21",          /*21*/
86         "R22",          /*22*/
87         "R23",          /*23*/
88         "R24",          /*24*/
89         "R25",          /*25*/
90         "R26",          /*26*/
91         "R27",          /*27*/
92         "R28",          /*28*/
93         "R29",          /*29*/
94         "R30",          /*30*/
95         "R31",          /*31*/
96 };
97
98
99 static void dump_port_status(u32 status)
100 {
101         int i = 0;
102
103         printk(KERN_DEBUG "status %08x:", status);
104         for (i = 0; i < 32; i++) {
105                 if (status & (1 << i))
106                         printk(" %s", bit_desc[i]);
107         }
108
109         printk("\n");
110 }
111
112
113
114 void rh_port_connect(int rhport, enum usb_device_speed speed)
115 {
116         unsigned long   flags;
117
118         dbg_vhci_rh("rh_port_connect %d\n", rhport);
119
120         spin_lock_irqsave(&the_controller->lock, flags);
121
122         the_controller->port_status[rhport] |= USB_PORT_STAT_CONNECTION
123                 | (1 << USB_PORT_FEAT_C_CONNECTION);
124
125         switch (speed) {
126         case USB_SPEED_HIGH:
127                 the_controller->port_status[rhport] |= USB_PORT_STAT_HIGH_SPEED;
128                 break;
129         case USB_SPEED_LOW:
130                 the_controller->port_status[rhport] |= USB_PORT_STAT_LOW_SPEED;
131                 break;
132         default:
133                 break;
134         }
135
136         /* spin_lock(&the_controller->vdev[rhport].ud.lock);
137          * the_controller->vdev[rhport].ud.status = VDEV_CONNECT;
138          * spin_unlock(&the_controller->vdev[rhport].ud.lock); */
139
140         the_controller->pending_port = rhport;
141
142         spin_unlock_irqrestore(&the_controller->lock, flags);
143
144         usb_hcd_poll_rh_status(vhci_to_hcd(the_controller));
145 }
146
147 void rh_port_disconnect(int rhport)
148 {
149         unsigned long flags;
150
151         dbg_vhci_rh("rh_port_disconnect %d\n", rhport);
152
153         spin_lock_irqsave(&the_controller->lock, flags);
154         /* stop_activity(dum, driver); */
155         the_controller->port_status[rhport] &= ~USB_PORT_STAT_CONNECTION;
156         the_controller->port_status[rhport] |=
157                                         (1 << USB_PORT_FEAT_C_CONNECTION);
158
159
160         /* not yet complete the disconnection
161          * spin_lock(&vdev->ud.lock);
162          * vdev->ud.status = VHC_ST_DISCONNECT;
163          * spin_unlock(&vdev->ud.lock); */
164
165         spin_unlock_irqrestore(&the_controller->lock, flags);
166 }
167
168
169
170 /*----------------------------------------------------------------------*/
171
172 #define PORT_C_MASK \
173         ((USB_PORT_STAT_C_CONNECTION \
174           | USB_PORT_STAT_C_ENABLE \
175           | USB_PORT_STAT_C_SUSPEND \
176           | USB_PORT_STAT_C_OVERCURRENT \
177           | USB_PORT_STAT_C_RESET) << 16)
178
179 /*
180  * This function is almostly the same as dummy_hcd.c:dummy_hub_status() without
181  * suspend/resume support. But, it is modified to provide multiple ports.
182  *
183  * @buf: a bitmap to show which port status has been changed.
184  *  bit  0: reserved or used for another purpose?
185  *  bit  1: the status of port 0 has been changed.
186  *  bit  2: the status of port 1 has been changed.
187  *  ...
188  *  bit  7: the status of port 6 has been changed.
189  *  bit  8: the status of port 7 has been changed.
190  *  ...
191  *  bit 15: the status of port 14 has been changed.
192  *
193  * So, the maximum number of ports is 31 ( port 0 to port 30) ?
194  *
195  * The return value is the actual transfered length in byte. If nothing has
196  * been changed, return 0. In the case that the number of ports is less than or
197  * equal to 6 (VHCI_NPORTS==7), return 1.
198  *
199  */
200 static int vhci_hub_status(struct usb_hcd *hcd, char *buf)
201 {
202         struct vhci_hcd *vhci;
203         unsigned long   flags;
204         int             retval = 0;
205
206         /* the enough buffer is allocated according to USB_MAXCHILDREN */
207         unsigned long   *event_bits = (unsigned long *) buf;
208         int             rhport;
209         int             changed = 0;
210
211
212         *event_bits = 0;
213
214         vhci = hcd_to_vhci(hcd);
215
216         spin_lock_irqsave(&vhci->lock, flags);
217         if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
218                 dbg_vhci_rh("hw accessible flag in on?\n");
219                 goto done;
220         }
221
222         /* check pseudo status register for each port */
223         for (rhport = 0; rhport < VHCI_NPORTS; rhport++) {
224                 if ((vhci->port_status[rhport] & PORT_C_MASK)) {
225                         /* The status of a port has been changed, */
226                         dbg_vhci_rh("port %d is changed\n", rhport);
227
228                         *event_bits |= 1 << (rhport + 1);
229                         changed = 1;
230                 }
231         }
232
233         uinfo("changed %d\n", changed);
234
235         if (hcd->state == HC_STATE_SUSPENDED)
236                 usb_hcd_resume_root_hub(hcd);
237
238         if (changed)
239                 retval = 1 + (VHCI_NPORTS / 8);
240         else
241                 retval = 0;
242
243 done:
244         spin_unlock_irqrestore(&vhci->lock, flags);
245         return retval;
246 }
247
248 /* See hub_configure in hub.c */
249 static inline void hub_descriptor(struct usb_hub_descriptor *desc)
250 {
251         memset(desc, 0, sizeof(*desc));
252         desc->bDescriptorType = 0x29;
253         desc->bDescLength = 9;
254         desc->wHubCharacteristics = (__force __u16)
255                 (__constant_cpu_to_le16(0x0001));
256         desc->bNbrPorts = VHCI_NPORTS;
257         desc->bitmap[0] = 0xff;
258         desc->bitmap[1] = 0xff;
259 }
260
261 static int vhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
262                             u16 wIndex, char *buf, u16 wLength)
263 {
264         struct vhci_hcd *dum;
265         int             retval = 0;
266         unsigned long   flags;
267         int             rhport;
268
269         u32 prev_port_status[VHCI_NPORTS];
270
271         if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))
272                 return -ETIMEDOUT;
273
274         /*
275          * NOTE:
276          * wIndex shows the port number and begins from 1.
277          */
278         dbg_vhci_rh("typeReq %x wValue %x wIndex %x\n", typeReq, wValue,
279                                                                 wIndex);
280         if (wIndex > VHCI_NPORTS)
281                 printk(KERN_ERR "%s: invalid port number %d\n", __func__, wIndex);
282         rhport = ((__u8)(wIndex & 0x00ff)) - 1;
283
284         dum = hcd_to_vhci(hcd);
285
286         spin_lock_irqsave(&dum->lock, flags);
287
288         /* store old status and compare now and old later */
289         if (dbg_flag_vhci_rh) {
290                 int i = 0;
291                 for (i = 0; i < VHCI_NPORTS; i++)
292                         prev_port_status[i] = dum->port_status[i];
293         }
294
295         switch (typeReq) {
296         case ClearHubFeature:
297                 dbg_vhci_rh(" ClearHubFeature\n");
298                 break;
299         case ClearPortFeature:
300                 switch (wValue) {
301                 case USB_PORT_FEAT_SUSPEND:
302                         if (dum->port_status[rhport] & USB_PORT_STAT_SUSPEND) {
303                                 /* 20msec signaling */
304                                 dum->resuming = 1;
305                                 dum->re_timeout =
306                                         jiffies + msecs_to_jiffies(20);
307                         }
308                         break;
309                 case USB_PORT_FEAT_POWER:
310                         dbg_vhci_rh(" ClearPortFeature: USB_PORT_FEAT_POWER\n");
311                         dum->port_status[rhport] = 0;
312                         /* dum->address = 0; */
313                         /* dum->hdev = 0; */
314                         dum->resuming = 0;
315                         break;
316                 case USB_PORT_FEAT_C_RESET:
317                         dbg_vhci_rh(" ClearPortFeature: "
318                                         "USB_PORT_FEAT_C_RESET\n");
319                         switch (dum->vdev[rhport].speed) {
320                         case USB_SPEED_HIGH:
321                                 dum->port_status[rhport] |=
322                                                 USB_PORT_STAT_HIGH_SPEED;
323                                 break;
324                         case USB_SPEED_LOW:
325                                 dum->port_status[rhport] |=
326                                                 USB_PORT_STAT_LOW_SPEED;
327                                 break;
328                         default:
329                                 break;
330                         }
331                 default:
332                         dbg_vhci_rh(" ClearPortFeature: default %x\n", wValue);
333                         dum->port_status[rhport] &= ~(1 << wValue);
334                 }
335                 break;
336         case GetHubDescriptor:
337                 dbg_vhci_rh(" GetHubDescriptor\n");
338                 hub_descriptor((struct usb_hub_descriptor *) buf);
339                 break;
340         case GetHubStatus:
341                 dbg_vhci_rh(" GetHubStatus\n");
342                 *(__le32 *) buf = __constant_cpu_to_le32(0);
343                 break;
344         case GetPortStatus:
345                 dbg_vhci_rh(" GetPortStatus port %x\n", wIndex);
346                 if (wIndex > VHCI_NPORTS || wIndex < 1) {
347                         printk(KERN_ERR "%s: invalid port number %d\n",
348                                __func__, wIndex);
349                         retval = -EPIPE;
350                 }
351
352                 /* we do no care of resume. */
353
354                 /* whoever resets or resumes must GetPortStatus to
355                  * complete it!!
356                  *                                   */
357                 if (dum->resuming && time_after(jiffies, dum->re_timeout)) {
358                         printk(KERN_ERR "%s: not yet\n", __func__);
359                         dum->port_status[rhport] |=
360                                         (1 << USB_PORT_FEAT_C_SUSPEND);
361                         dum->port_status[rhport] &=
362                                         ~(1 << USB_PORT_FEAT_SUSPEND);
363                         dum->resuming = 0;
364                         dum->re_timeout = 0;
365                         /* if (dum->driver && dum->driver->resume) {
366                          *      spin_unlock (&dum->lock);
367                          *      dum->driver->resume (&dum->gadget);
368                          *      spin_lock (&dum->lock);
369                          * } */
370                 }
371
372                 if ((dum->port_status[rhport] & (1 << USB_PORT_FEAT_RESET)) !=
373                                 0 && time_after(jiffies, dum->re_timeout)) {
374                         dum->port_status[rhport] |=
375                                                 (1 << USB_PORT_FEAT_C_RESET);
376                         dum->port_status[rhport] &=
377                                                 ~(1 << USB_PORT_FEAT_RESET);
378                         dum->re_timeout = 0;
379
380                         if (dum->vdev[rhport].ud.status ==
381                                                         VDEV_ST_NOTASSIGNED) {
382                                 dbg_vhci_rh(" enable rhport %d (status %u)\n",
383                                                 rhport,
384                                                 dum->vdev[rhport].ud.status);
385                                 dum->port_status[rhport] |=
386                                                         USB_PORT_STAT_ENABLE;
387                         }
388 #if 0
389                         if (dum->driver) {
390
391                                 dum->port_status[rhport] |=
392                                                         USB_PORT_STAT_ENABLE;
393                                 /* give it the best speed we agree on */
394                                 dum->gadget.speed = dum->driver->speed;
395                                 dum->gadget.ep0->maxpacket = 64;
396                                 switch (dum->gadget.speed) {
397                                 case USB_SPEED_HIGH:
398                                         dum->port_status[rhport] |=
399                                         USB_PORT_STAT_HIGH_SPEED;
400                                         break;
401                                 case USB_SPEED_LOW:
402                                         dum->gadget.ep0->maxpacket = 8;
403                                         dum->port_status[rhport] |=
404                                         USB_PORT_STAT_LOW_SPEED;
405                                         break;
406                                 default:
407                                         dum->gadget.speed = USB_SPEED_FULL;
408                                         break;
409                                 }
410                         }
411 #endif
412
413                 }
414                 ((u16 *) buf)[0] = cpu_to_le16(dum->port_status[rhport]);
415                 ((u16 *) buf)[1] =
416                                 cpu_to_le16(dum->port_status[rhport] >> 16);
417
418                 dbg_vhci_rh(" GetPortStatus bye %x %x\n", ((u16 *)buf)[0],
419                                                         ((u16 *)buf)[1]);
420                 break;
421         case SetHubFeature:
422                 dbg_vhci_rh(" SetHubFeature\n");
423                 retval = -EPIPE;
424                 break;
425         case SetPortFeature:
426                 switch (wValue) {
427                 case USB_PORT_FEAT_SUSPEND:
428                         dbg_vhci_rh(" SetPortFeature: "
429                                         "USB_PORT_FEAT_SUSPEND\n");
430                         printk(KERN_ERR "%s: not yet\n", __func__);
431 #if 0
432                         dum->port_status[rhport] |=
433                                                 (1 << USB_PORT_FEAT_SUSPEND);
434                         if (dum->driver->suspend) {
435                                 spin_unlock(&dum->lock);
436                                 dum->driver->suspend(&dum->gadget);
437                                 spin_lock(&dum->lock);
438                         }
439 #endif
440                         break;
441                 case USB_PORT_FEAT_RESET:
442                         dbg_vhci_rh(" SetPortFeature: USB_PORT_FEAT_RESET\n");
443                         /* if it's already running, disconnect first */
444                         if (dum->port_status[rhport] & USB_PORT_STAT_ENABLE) {
445                                 dum->port_status[rhport] &=
446                                                 ~(USB_PORT_STAT_ENABLE |
447                                                   USB_PORT_STAT_LOW_SPEED |
448                                                   USB_PORT_STAT_HIGH_SPEED);
449 #if 0
450                                 if (dum->driver) {
451                                         dev_dbg(hardware, "disconnect\n");
452                                         stop_activity(dum, dum->driver);
453                                 }
454 #endif
455
456                                 /* FIXME test that code path! */
457                         }
458                         /* 50msec reset signaling */
459                         dum->re_timeout = jiffies + msecs_to_jiffies(50);
460
461                         /* FALLTHROUGH */
462                 default:
463                         dbg_vhci_rh(" SetPortFeature: default %d\n", wValue);
464                         dum->port_status[rhport] |= (1 << wValue);
465                 }
466                 break;
467
468         default:
469                 printk(KERN_ERR "%s: default: no such request\n", __func__);
470                 /* dev_dbg (hardware,
471                  *              "hub control req%04x v%04x i%04x l%d\n",
472                  *              typeReq, wValue, wIndex, wLength); */
473
474                 /* "protocol stall" on error */
475                 retval = -EPIPE;
476         }
477
478         if (dbg_flag_vhci_rh) {
479                 printk(KERN_DEBUG "port %d\n", rhport);
480                 dump_port_status(prev_port_status[rhport]);
481                 dump_port_status(dum->port_status[rhport]);
482         }
483         dbg_vhci_rh(" bye\n");
484
485         spin_unlock_irqrestore(&dum->lock, flags);
486
487         return retval;
488 }
489
490
491
492 /*----------------------------------------------------------------------*/
493
494 static struct vhci_device *get_vdev(struct usb_device *udev)
495 {
496         int i;
497
498         if (!udev)
499                 return NULL;
500
501         for (i = 0; i < VHCI_NPORTS; i++)
502                 if (the_controller->vdev[i].udev == udev)
503                         return port_to_vdev(i);
504
505         return NULL;
506 }
507
508 static void vhci_tx_urb(struct urb *urb)
509 {
510         struct vhci_device *vdev = get_vdev(urb->dev);
511         struct vhci_priv *priv;
512         unsigned long flag;
513
514         if (!vdev) {
515                 err("could not get virtual device");
516                 /* BUG(); */
517                 return;
518         }
519
520         spin_lock_irqsave(&vdev->priv_lock, flag);
521
522         priv = kzalloc(sizeof(struct vhci_priv), GFP_ATOMIC);
523         if (!priv) {
524                 dev_err(&urb->dev->dev, "malloc vhci_priv\n");
525                 spin_unlock_irqrestore(&vdev->priv_lock, flag);
526                 usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_MALLOC);
527                 return;
528         }
529
530         priv->seqnum = atomic_inc_return(&the_controller->seqnum);
531         if (priv->seqnum == 0xffff)
532                 uinfo("seqnum max\n");
533
534         priv->vdev = vdev;
535         priv->urb = urb;
536
537         urb->hcpriv = (void *) priv;
538
539
540         list_add_tail(&priv->list, &vdev->priv_tx);
541
542         wake_up(&vdev->waitq_tx);
543         spin_unlock_irqrestore(&vdev->priv_lock, flag);
544 }
545
546 static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
547                             gfp_t mem_flags)
548 {
549         struct device *dev = &urb->dev->dev;
550         int ret = 0;
551         unsigned long flags;
552
553         dbg_vhci_hc("enter, usb_hcd %p urb %p mem_flags %d\n",
554                     hcd, urb, mem_flags);
555
556         /* patch to usb_sg_init() is in 2.5.60 */
557         BUG_ON(!urb->transfer_buffer && urb->transfer_buffer_length);
558
559         spin_lock_irqsave(&the_controller->lock, flags);
560
561         /* check HC is active or not */
562         if (!HC_IS_RUNNING(hcd->state)) {
563                 dev_err(dev, "HC is not running\n");
564                 spin_unlock_irqrestore(&the_controller->lock, flags);
565                 return -ENODEV;
566         }
567
568         if (urb->status != -EINPROGRESS) {
569                 dev_err(dev, "URB already unlinked!, status %d\n", urb->status);
570                 spin_unlock_irqrestore(&the_controller->lock, flags);
571                 return urb->status;
572         }
573
574         ret = usb_hcd_link_urb_to_ep(hcd, urb);
575         if (ret)
576                 goto no_need_unlink;
577
578         /*
579          * The enumelation process is as follows;
580          *
581          *  1. Get_Descriptor request to DevAddrs(0) EndPoint(0)
582          *     to get max packet length of default pipe
583          *
584          *  2. Set_Address request to DevAddr(0) EndPoint(0)
585          *
586          */
587
588         if (usb_pipedevice(urb->pipe) == 0) {
589                 __u8 type = usb_pipetype(urb->pipe);
590                 struct usb_ctrlrequest *ctrlreq =
591                                 (struct usb_ctrlrequest *) urb->setup_packet;
592                 struct vhci_device *vdev =
593                                 port_to_vdev(the_controller->pending_port);
594
595                 if (type != PIPE_CONTROL || !ctrlreq) {
596                         dev_err(dev, "invalid request to devnum 0\n");
597                         ret = EINVAL;
598                         goto no_need_xmit;
599                 }
600
601                 switch (ctrlreq->bRequest) {
602                 case USB_REQ_SET_ADDRESS:
603                         /* set_address may come when a device is reset */
604                         dev_info(dev, "SetAddress Request (%d) to port %d\n",
605                                  ctrlreq->wValue, vdev->rhport);
606
607                         vdev->udev = urb->dev;
608
609                         spin_lock(&vdev->ud.lock);
610                         vdev->ud.status = VDEV_ST_USED;
611                         spin_unlock(&vdev->ud.lock);
612
613                         if (urb->status == -EINPROGRESS) {
614                                 /* This request is successfully completed. */
615                                 /* If not -EINPROGRESS, possibly unlinked. */
616                                 urb->status = 0;
617                         }
618
619                         goto no_need_xmit;
620
621                 case USB_REQ_GET_DESCRIPTOR:
622                         if (ctrlreq->wValue == (USB_DT_DEVICE << 8))
623                                 dbg_vhci_hc("Not yet?: "
624                                                 "Get_Descriptor to device 0 "
625                                                 "(get max pipe size)\n");
626
627                         /* FIXME: reference count? (usb_get_dev()) */
628                         vdev->udev = urb->dev;
629                         goto out;
630
631                 default:
632                         /* NOT REACHED */
633                         dev_err(dev, "invalid request to devnum 0 bRequest %u, "
634                                 "wValue %u\n", ctrlreq->bRequest,
635                                 ctrlreq->wValue);
636                         ret =  -EINVAL;
637                         goto no_need_xmit;
638                 }
639
640         }
641
642 out:
643         vhci_tx_urb(urb);
644
645         spin_unlock_irqrestore(&the_controller->lock, flags);
646
647         return 0;
648
649 no_need_xmit:
650         usb_hcd_unlink_urb_from_ep(hcd, urb);
651 no_need_unlink:
652         spin_unlock_irqrestore(&the_controller->lock, flags);
653
654         usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);
655
656         return 0;
657 }
658
659 /*
660  * vhci_rx gives back the urb after receiving the reply of the urb.  If an
661  * unlink pdu is sent or not, vhci_rx receives a normal return pdu and gives
662  * back its urb. For the driver unlinking the urb, the content of the urb is
663  * not important, but the calling to its completion handler is important; the
664  * completion of unlinking is notified by the completion handler.
665  *
666  *
667  * CLIENT SIDE
668  *
669  * - When vhci_hcd receives RET_SUBMIT,
670  *
671  *      - case 1a). the urb of the pdu is not unlinking.
672  *              - normal case
673  *              => just give back the urb
674  *
675  *      - case 1b). the urb of the pdu is unlinking.
676  *              - usbip.ko will return a reply of the unlinking request.
677  *              => give back the urb now and go to case 2b).
678  *
679  * - When vhci_hcd receives RET_UNLINK,
680  *
681  *      - case 2a). a submit request is still pending in vhci_hcd.
682  *              - urb was really pending in usbip.ko and urb_unlink_urb() was
683  *                completed there.
684  *              => free a pending submit request
685  *              => notify unlink completeness by giving back the urb
686  *
687  *      - case 2b). a submit request is *not* pending in vhci_hcd.
688  *              - urb was already given back to the core driver.
689  *              => do not give back the urb
690  *
691  *
692  * SERVER SIDE
693  *
694  * - When usbip receives CMD_UNLINK,
695  *
696  *      - case 3a). the urb of the unlink request is now in submission.
697  *              => do usb_unlink_urb().
698  *              => after the unlink is completed, send RET_UNLINK.
699  *
700  *      - case 3b). the urb of the unlink request is not in submission.
701  *              - may be already completed or never be received
702  *              => send RET_UNLINK
703  *
704  */
705 static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
706 {
707         unsigned long flags;
708         struct vhci_priv *priv;
709         struct vhci_device *vdev;
710
711         uinfo("vhci_hcd: dequeue a urb %p\n", urb);
712
713
714         spin_lock_irqsave(&the_controller->lock, flags);
715
716         priv = urb->hcpriv;
717         if (!priv) {
718                 /* URB was never linked! or will be soon given back by
719                  * vhci_rx. */
720                 spin_unlock_irqrestore(&the_controller->lock, flags);
721                 return 0;
722         }
723
724         {
725                 int ret = 0;
726                 ret = usb_hcd_check_unlink_urb(hcd, urb, status);
727                 if (ret) {
728                         spin_unlock_irqrestore(&the_controller->lock, flags);
729                         return 0;
730                 }
731         }
732
733          /* send unlink request here? */
734         vdev = priv->vdev;
735
736         if (!vdev->ud.tcp_socket) {
737                 /* tcp connection is closed */
738                 unsigned long flags2;
739
740                 spin_lock_irqsave(&vdev->priv_lock, flags2);
741
742                 uinfo("vhci_hcd: device %p seems to be disconnected\n", vdev);
743                 list_del(&priv->list);
744                 kfree(priv);
745                 urb->hcpriv = NULL;
746
747                 spin_unlock_irqrestore(&vdev->priv_lock, flags2);
748
749         } else {
750                 /* tcp connection is alive */
751                 unsigned long flags2;
752                 struct vhci_unlink *unlink;
753
754                 spin_lock_irqsave(&vdev->priv_lock, flags2);
755
756                 /* setup CMD_UNLINK pdu */
757                 unlink = kzalloc(sizeof(struct vhci_unlink), GFP_ATOMIC);
758                 if (!unlink) {
759                         uerr("malloc vhci_unlink\n");
760                         spin_unlock_irqrestore(&vdev->priv_lock, flags2);
761                         spin_unlock_irqrestore(&the_controller->lock, flags);
762                         usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_MALLOC);
763                         return -ENOMEM;
764                 }
765
766                 unlink->seqnum = atomic_inc_return(&the_controller->seqnum);
767                 if (unlink->seqnum == 0xffff)
768                         uinfo("seqnum max\n");
769
770                 unlink->unlink_seqnum = priv->seqnum;
771
772                 uinfo("vhci_hcd: device %p seems to be still connected\n",
773                                                                         vdev);
774
775                 /* send cmd_unlink and try to cancel the pending URB in the
776                  * peer */
777                 list_add_tail(&unlink->list, &vdev->unlink_tx);
778                 wake_up(&vdev->waitq_tx);
779
780                 spin_unlock_irqrestore(&vdev->priv_lock, flags2);
781         }
782
783
784         /*
785          * If tcp connection is alive, we have sent CMD_UNLINK.
786          * vhci_rx will receive RET_UNLINK and give back the URB.
787          * Otherwise, we give back it here.
788          */
789         if (!vdev->ud.tcp_socket) {
790                 /* tcp connection is closed */
791                 uinfo("vhci_hcd: vhci_urb_dequeue() gives back urb %p\n", urb);
792
793                 usb_hcd_unlink_urb_from_ep(hcd, urb);
794
795                 spin_unlock_irqrestore(&the_controller->lock, flags);
796                 usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
797                                                                 urb->status);
798                 spin_lock_irqsave(&the_controller->lock, flags);
799         }
800
801         spin_unlock_irqrestore(&the_controller->lock, flags);
802
803         dbg_vhci_hc("leave\n");
804         return 0;
805 }
806
807
808 static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
809 {
810         struct vhci_unlink *unlink, *tmp;
811
812         spin_lock(&vdev->priv_lock);
813
814         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
815                 list_del(&unlink->list);
816                 kfree(unlink);
817         }
818
819         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
820                 list_del(&unlink->list);
821                 kfree(unlink);
822         }
823
824         spin_unlock(&vdev->priv_lock);
825 }
826
827 /*
828  * The important thing is that only one context begins cleanup.
829  * This is why error handling and cleanup become simple.
830  * We do not want to consider race condition as possible.
831  */
832 static void vhci_shutdown_connection(struct usbip_device *ud)
833 {
834         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
835
836         /* need this? see stub_dev.c */
837         if (ud->tcp_socket) {
838                 udbg("shutdown tcp_socket %p\n", ud->tcp_socket);
839                 kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
840         }
841
842         usbip_stop_threads(&vdev->ud);
843         uinfo("stop threads\n");
844
845         /* active connection is closed */
846         if (vdev->ud.tcp_socket != NULL) {
847                 sock_release(vdev->ud.tcp_socket);
848                 vdev->ud.tcp_socket = NULL;
849         }
850         uinfo("release socket\n");
851
852         vhci_device_unlink_cleanup(vdev);
853
854         /*
855          * rh_port_disconnect() is a trigger of ...
856          *   usb_disable_device():
857          *      disable all the endpoints for a USB device.
858          *   usb_disable_endpoint():
859          *      disable endpoints. pending urbs are unlinked(dequeued).
860          *
861          * NOTE: After calling rh_port_disconnect(), the USB device drivers of a
862          * deteched device should release used urbs in a cleanup function(i.e.
863          * xxx_disconnect()). Therefore, vhci_hcd does not need to release
864          * pushed urbs and their private data in this function.
865          *
866          * NOTE: vhci_dequeue() must be considered carefully. When shutdowning
867          * a connection, vhci_shutdown_connection() expects vhci_dequeue()
868          * gives back pushed urbs and frees their private data by request of
869          * the cleanup function of a USB driver. When unlinking a urb with an
870          * active connection, vhci_dequeue() does not give back the urb which
871          * is actually given back by vhci_rx after receiving its return pdu.
872          *
873          */
874         rh_port_disconnect(vdev->rhport);
875
876         uinfo("disconnect device\n");
877 }
878
879
880 static void vhci_device_reset(struct usbip_device *ud)
881 {
882         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
883
884         spin_lock(&ud->lock);
885
886         vdev->speed  = 0;
887         vdev->devid  = 0;
888
889         ud->tcp_socket = NULL;
890
891         ud->status = VDEV_ST_NULL;
892
893         spin_unlock(&ud->lock);
894 }
895
896 static void vhci_device_unusable(struct usbip_device *ud)
897 {
898         spin_lock(&ud->lock);
899
900         ud->status = VDEV_ST_ERROR;
901
902         spin_unlock(&ud->lock);
903 }
904
905 static void vhci_device_init(struct vhci_device *vdev)
906 {
907         memset(vdev, 0, sizeof(*vdev));
908
909         usbip_task_init(&vdev->ud.tcp_rx, "vhci_rx", vhci_rx_loop);
910         usbip_task_init(&vdev->ud.tcp_tx, "vhci_tx", vhci_tx_loop);
911
912         vdev->ud.side   = USBIP_VHCI;
913         vdev->ud.status = VDEV_ST_NULL;
914         /* vdev->ud.lock   = SPIN_LOCK_UNLOCKED; */
915         spin_lock_init(&vdev->ud.lock);
916
917         INIT_LIST_HEAD(&vdev->priv_rx);
918         INIT_LIST_HEAD(&vdev->priv_tx);
919         INIT_LIST_HEAD(&vdev->unlink_tx);
920         INIT_LIST_HEAD(&vdev->unlink_rx);
921         /* vdev->priv_lock = SPIN_LOCK_UNLOCKED; */
922         spin_lock_init(&vdev->priv_lock);
923
924         init_waitqueue_head(&vdev->waitq_tx);
925
926         vdev->ud.eh_ops.shutdown = vhci_shutdown_connection;
927         vdev->ud.eh_ops.reset = vhci_device_reset;
928         vdev->ud.eh_ops.unusable = vhci_device_unusable;
929
930         usbip_start_eh(&vdev->ud);
931 }
932
933
934 /*----------------------------------------------------------------------*/
935
936 static int vhci_start(struct usb_hcd *hcd)
937 {
938         struct vhci_hcd *vhci = hcd_to_vhci(hcd);
939         int rhport;
940         int err = 0;
941
942         dbg_vhci_hc("enter vhci_start\n");
943
944
945         /* initialize private data of usb_hcd */
946
947         for (rhport = 0; rhport < VHCI_NPORTS; rhport++) {
948                 struct vhci_device *vdev = &vhci->vdev[rhport];
949                 vhci_device_init(vdev);
950                 vdev->rhport = rhport;
951         }
952
953         atomic_set(&vhci->seqnum, 0);
954         spin_lock_init(&vhci->lock);
955
956
957
958         hcd->power_budget = 0; /* no limit */
959         hcd->state  = HC_STATE_RUNNING;
960         hcd->uses_new_polling = 1;
961
962
963         /* vhci_hcd is now ready to be controlled through sysfs */
964         err = sysfs_create_group(&vhci_dev(vhci)->kobj, &dev_attr_group);
965         if (err) {
966                 uerr("create sysfs files\n");
967                 return err;
968         }
969
970         return 0;
971 }
972
973 static void vhci_stop(struct usb_hcd *hcd)
974 {
975         struct vhci_hcd *vhci = hcd_to_vhci(hcd);
976         int rhport = 0;
977
978         dbg_vhci_hc("stop VHCI controller\n");
979
980
981         /* 1. remove the userland interface of vhci_hcd */
982         sysfs_remove_group(&vhci_dev(vhci)->kobj, &dev_attr_group);
983
984         /* 2. shutdown all the ports of vhci_hcd */
985         for (rhport = 0 ; rhport < VHCI_NPORTS; rhport++) {
986                 struct vhci_device *vdev = &vhci->vdev[rhport];
987
988                 usbip_event_add(&vdev->ud, VDEV_EVENT_REMOVED);
989                 usbip_stop_eh(&vdev->ud);
990         }
991
992
993         uinfo("vhci_stop done\n");
994 }
995
996 /*----------------------------------------------------------------------*/
997
998 static int vhci_get_frame_number(struct usb_hcd *hcd)
999 {
1000         uerr("Not yet implemented\n");
1001         return 0;
1002 }
1003
1004
1005 #ifdef CONFIG_PM
1006
1007 /* FIXME: suspend/resume */
1008 static int vhci_bus_suspend(struct usb_hcd *hcd)
1009 {
1010         struct vhci_hcd *vhci = hcd_to_vhci(hcd);
1011
1012         dev_dbg(&hcd->self.root_hub->dev, "%s\n", __func__);
1013
1014         spin_lock_irq(&vhci->lock);
1015         /* vhci->rh_state = DUMMY_RH_SUSPENDED;
1016          * set_link_state(vhci); */
1017         hcd->state = HC_STATE_SUSPENDED;
1018         spin_unlock_irq(&vhci->lock);
1019
1020         return 0;
1021 }
1022
1023 static int vhci_bus_resume(struct usb_hcd *hcd)
1024 {
1025         struct vhci_hcd *vhci = hcd_to_vhci(hcd);
1026         int rc = 0;
1027
1028         dev_dbg(&hcd->self.root_hub->dev, "%s\n", __func__);
1029
1030         spin_lock_irq(&vhci->lock);
1031         if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
1032                 rc = -ESHUTDOWN;
1033         } else {
1034                 /* vhci->rh_state = DUMMY_RH_RUNNING;
1035                  * set_link_state(vhci);
1036                  * if (!list_empty(&vhci->urbp_list))
1037                  *      mod_timer(&vhci->timer, jiffies); */
1038                 hcd->state = HC_STATE_RUNNING;
1039         }
1040         spin_unlock_irq(&vhci->lock);
1041         return rc;
1042
1043         return 0;
1044 }
1045
1046 #else
1047
1048 #define vhci_bus_suspend      NULL
1049 #define vhci_bus_resume       NULL
1050 #endif
1051
1052
1053
1054 static struct hc_driver vhci_hc_driver = {
1055         .description    = driver_name,
1056         .product_desc   = driver_desc,
1057         .hcd_priv_size  = sizeof(struct vhci_hcd),
1058
1059         .flags          = HCD_USB2,
1060
1061         .start          = vhci_start,
1062         .stop           = vhci_stop,
1063
1064         .urb_enqueue    = vhci_urb_enqueue,
1065         .urb_dequeue    = vhci_urb_dequeue,
1066
1067         .get_frame_number = vhci_get_frame_number,
1068
1069         .hub_status_data = vhci_hub_status,
1070         .hub_control    = vhci_hub_control,
1071         .bus_suspend    = vhci_bus_suspend,
1072         .bus_resume     = vhci_bus_resume,
1073 };
1074
1075 static int vhci_hcd_probe(struct platform_device *pdev)
1076 {
1077         struct usb_hcd          *hcd;
1078         int                     ret;
1079
1080         uinfo("proving...\n");
1081
1082         dbg_vhci_hc("name %s id %d\n", pdev->name, pdev->id);
1083
1084         /* will be removed */
1085         if (pdev->dev.dma_mask) {
1086                 dev_info(&pdev->dev, "vhci_hcd DMA not supported\n");
1087                 return -EINVAL;
1088         }
1089
1090         /*
1091          * Allocate and initialize hcd.
1092          * Our private data is also allocated automatically.
1093          */
1094         hcd = usb_create_hcd(&vhci_hc_driver, &pdev->dev, pdev->dev.bus_id);
1095         if (!hcd) {
1096                 uerr("create hcd failed\n");
1097                 return -ENOMEM;
1098         }
1099
1100
1101         /* this is private data for vhci_hcd */
1102         the_controller = hcd_to_vhci(hcd);
1103
1104         /*
1105          * Finish generic HCD structure initialization and register.
1106          * Call the driver's reset() and start() routines.
1107          */
1108         ret = usb_add_hcd(hcd, 0, 0);
1109         if (ret != 0) {
1110                 uerr("usb_add_hcd failed %d\n", ret);
1111                 usb_put_hcd(hcd);
1112                 the_controller = NULL;
1113                 return ret;
1114         }
1115
1116
1117         dbg_vhci_hc("bye\n");
1118         return 0;
1119 }
1120
1121
1122 static int vhci_hcd_remove(struct platform_device *pdev)
1123 {
1124         struct usb_hcd  *hcd;
1125
1126         hcd = platform_get_drvdata(pdev);
1127         if (!hcd)
1128                 return 0;
1129
1130         /*
1131          * Disconnects the root hub,
1132          * then reverses the effects of usb_add_hcd(),
1133          * invoking the HCD's stop() methods.
1134          */
1135         usb_remove_hcd(hcd);
1136         usb_put_hcd(hcd);
1137         the_controller = NULL;
1138
1139
1140         return 0;
1141 }
1142
1143
1144
1145 #ifdef CONFIG_PM
1146
1147 /* what should happen for USB/IP under suspend/resume? */
1148 static int vhci_hcd_suspend(struct platform_device *pdev, pm_message_t state)
1149 {
1150         struct usb_hcd *hcd;
1151         int rhport = 0;
1152         int connected = 0;
1153         int ret = 0;
1154
1155         dev_dbg(&pdev->dev, "%s\n", __func__);
1156
1157         hcd = platform_get_drvdata(pdev);
1158
1159         spin_lock(&the_controller->lock);
1160
1161         for (rhport = 0; rhport < VHCI_NPORTS; rhport++)
1162                 if (the_controller->port_status[rhport] &
1163                                                 USB_PORT_STAT_CONNECTION)
1164                         connected += 1;
1165
1166         spin_unlock(&the_controller->lock);
1167
1168         if (connected > 0) {
1169                 uinfo("We have %d active connection%s. Do not suspend.\n",
1170                                 connected, (connected == 1 ? "" : "s"));
1171                 ret =  -EBUSY;
1172         } else {
1173                 uinfo("suspend vhci_hcd");
1174                 clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
1175         }
1176
1177         return ret;
1178 }
1179
1180 static int vhci_hcd_resume(struct platform_device *pdev)
1181 {
1182         struct usb_hcd *hcd;
1183
1184         dev_dbg(&pdev->dev, "%s\n", __func__);
1185
1186         hcd = platform_get_drvdata(pdev);
1187         set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
1188         usb_hcd_poll_rh_status(hcd);
1189
1190         return 0;
1191 }
1192
1193 #else
1194
1195 #define vhci_hcd_suspend        NULL
1196 #define vhci_hcd_resume         NULL
1197
1198 #endif
1199
1200
1201 static struct platform_driver vhci_driver = {
1202         .probe  = vhci_hcd_probe,
1203         .remove = __devexit_p(vhci_hcd_remove),
1204         .suspend = vhci_hcd_suspend,
1205         .resume = vhci_hcd_resume,
1206         .driver = {
1207                 .name = (char *) driver_name,
1208                 .owner = THIS_MODULE,
1209         },
1210 };
1211
1212 /*----------------------------------------------------------------------*/
1213
1214 /*
1215  * The VHCI 'device' is 'virtual'; not a real plug&play hardware.
1216  * We need to add this virtual device as a platform device arbitrarily:
1217  *      1. platform_device_register()
1218  */
1219 static void the_pdev_release(struct device *dev)
1220 {
1221         return;
1222 }
1223
1224 static struct platform_device the_pdev = {
1225         /* should be the same name as driver_name */
1226         .name = (char *) driver_name,
1227         .id = -1,
1228         .dev = {
1229                 /* .driver = &vhci_driver, */
1230                 .release = the_pdev_release,
1231         },
1232 };
1233
1234 static int __init vhci_init(void)
1235 {
1236         int ret;
1237
1238         dbg_vhci_hc("enter\n");
1239         if (usb_disabled())
1240                 return -ENODEV;
1241
1242         printk(KERN_INFO KBUILD_MODNAME ": %s, %s\n", driver_name,
1243                DRIVER_VERSION);
1244
1245         ret = platform_driver_register(&vhci_driver);
1246         if (ret < 0)
1247                 goto err_driver_register;
1248
1249         ret = platform_device_register(&the_pdev);
1250         if (ret < 0)
1251                 goto err_platform_device_register;
1252
1253         dbg_vhci_hc("bye\n");
1254         return ret;
1255
1256         /* error occurred */
1257 err_platform_device_register:
1258         platform_driver_unregister(&vhci_driver);
1259
1260 err_driver_register:
1261         dbg_vhci_hc("bye\n");
1262         return ret;
1263 }
1264 module_init(vhci_init);
1265
1266 static void __exit vhci_cleanup(void)
1267 {
1268         dbg_vhci_hc("enter\n");
1269
1270         platform_device_unregister(&the_pdev);
1271         platform_driver_unregister(&vhci_driver);
1272
1273         dbg_vhci_hc("bye\n");
1274 }
1275 module_exit(vhci_cleanup);