xref: /openbmc/qemu/hw/usb/hcd-ehci.c (revision 7562f907)
1 /*
2  * QEMU USB EHCI Emulation
3  *
4  * Copyright(c) 2008  Emutex Ltd. (address@hidden)
5  * Copyright(c) 2011-2012 Red Hat, Inc.
6  *
7  * Red Hat Authors:
8  * Gerd Hoffmann <kraxel@redhat.com>
9  * Hans de Goede <hdegoede@redhat.com>
10  *
11  * EHCI project was started by Mark Burkley, with contributions by
12  * Niels de Vos.  David S. Ahern continued working on it.  Kevin Wolf,
13  * Jan Kiszka and Vincent Palatin contributed bugfixes.
14  *
15  *
16  * This library is free software; you can redistribute it and/or
17  * modify it under the terms of the GNU Lesser General Public
18  * License as published by the Free Software Foundation; either
19  * version 2 of the License, or(at your option) any later version.
20  *
21  * This library is distributed in the hope that it will be useful,
22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24  * Lesser General Public License for more details.
25  *
26  * You should have received a copy of the GNU General Public License
27  * along with this program; if not, see <http://www.gnu.org/licenses/>.
28  */
29 
30 #include "qemu/osdep.h"
31 #include "qapi/error.h"
32 #include "hw/usb/ehci-regs.h"
33 #include "hw/usb/hcd-ehci.h"
34 #include "trace.h"
35 
36 #define FRAME_TIMER_FREQ 1000
37 #define FRAME_TIMER_NS   (NANOSECONDS_PER_SECOND / FRAME_TIMER_FREQ)
38 #define UFRAME_TIMER_NS  (FRAME_TIMER_NS / 8)
39 
40 #define NB_MAXINTRATE    8        // Max rate at which controller issues ints
41 #define BUFF_SIZE        5*4096   // Max bytes to transfer per transaction
42 #define MAX_QH           100      // Max allowable queue heads in a chain
43 #define MIN_UFR_PER_TICK 24       /* Min frames to process when catching up */
44 #define PERIODIC_ACTIVE  512      /* Micro-frames */
45 
46 /*  Internal periodic / asynchronous schedule state machine states
47  */
48 typedef enum {
49     EST_INACTIVE = 1000,
50     EST_ACTIVE,
51     EST_EXECUTING,
52     EST_SLEEPING,
53     /*  The following states are internal to the state machine function
54     */
55     EST_WAITLISTHEAD,
56     EST_FETCHENTRY,
57     EST_FETCHQH,
58     EST_FETCHITD,
59     EST_FETCHSITD,
60     EST_ADVANCEQUEUE,
61     EST_FETCHQTD,
62     EST_EXECUTE,
63     EST_WRITEBACK,
64     EST_HORIZONTALQH
65 } EHCI_STATES;
66 
67 /* macros for accessing fields within next link pointer entry */
68 #define NLPTR_GET(x)             ((x) & 0xffffffe0)
69 #define NLPTR_TYPE_GET(x)        (((x) >> 1) & 3)
70 #define NLPTR_TBIT(x)            ((x) & 1)  // 1=invalid, 0=valid
71 
72 /* link pointer types */
73 #define NLPTR_TYPE_ITD           0     // isoc xfer descriptor
74 #define NLPTR_TYPE_QH            1     // queue head
75 #define NLPTR_TYPE_STITD         2     // split xaction, isoc xfer descriptor
76 #define NLPTR_TYPE_FSTN          3     // frame span traversal node
77 
78 #define SET_LAST_RUN_CLOCK(s) \
79     (s)->last_run_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
80 
81 /* nifty macros from Arnon's EHCI version  */
82 #define get_field(data, field) \
83     (((data) & field##_MASK) >> field##_SH)
84 
85 #define set_field(data, newval, field) do { \
86     uint32_t val = *data; \
87     val &= ~ field##_MASK; \
88     val |= ((newval) << field##_SH) & field##_MASK; \
89     *data = val; \
90     } while(0)
91 
92 static const char *ehci_state_names[] = {
93     [EST_INACTIVE]     = "INACTIVE",
94     [EST_ACTIVE]       = "ACTIVE",
95     [EST_EXECUTING]    = "EXECUTING",
96     [EST_SLEEPING]     = "SLEEPING",
97     [EST_WAITLISTHEAD] = "WAITLISTHEAD",
98     [EST_FETCHENTRY]   = "FETCH ENTRY",
99     [EST_FETCHQH]      = "FETCH QH",
100     [EST_FETCHITD]     = "FETCH ITD",
101     [EST_ADVANCEQUEUE] = "ADVANCEQUEUE",
102     [EST_FETCHQTD]     = "FETCH QTD",
103     [EST_EXECUTE]      = "EXECUTE",
104     [EST_WRITEBACK]    = "WRITEBACK",
105     [EST_HORIZONTALQH] = "HORIZONTALQH",
106 };
107 
108 static const char *ehci_mmio_names[] = {
109     [USBCMD]            = "USBCMD",
110     [USBSTS]            = "USBSTS",
111     [USBINTR]           = "USBINTR",
112     [FRINDEX]           = "FRINDEX",
113     [PERIODICLISTBASE]  = "P-LIST BASE",
114     [ASYNCLISTADDR]     = "A-LIST ADDR",
115     [CONFIGFLAG]        = "CONFIGFLAG",
116 };
117 
118 static int ehci_state_executing(EHCIQueue *q);
119 static int ehci_state_writeback(EHCIQueue *q);
120 static int ehci_state_advqueue(EHCIQueue *q);
121 static int ehci_fill_queue(EHCIPacket *p);
122 static void ehci_free_packet(EHCIPacket *p);
123 
124 static const char *nr2str(const char **n, size_t len, uint32_t nr)
125 {
126     if (nr < len && n[nr] != NULL) {
127         return n[nr];
128     } else {
129         return "unknown";
130     }
131 }
132 
133 static const char *state2str(uint32_t state)
134 {
135     return nr2str(ehci_state_names, ARRAY_SIZE(ehci_state_names), state);
136 }
137 
138 static const char *addr2str(hwaddr addr)
139 {
140     return nr2str(ehci_mmio_names, ARRAY_SIZE(ehci_mmio_names), addr);
141 }
142 
143 static void ehci_trace_usbsts(uint32_t mask, int state)
144 {
145     /* interrupts */
146     if (mask & USBSTS_INT) {
147         trace_usb_ehci_usbsts("INT", state);
148     }
149     if (mask & USBSTS_ERRINT) {
150         trace_usb_ehci_usbsts("ERRINT", state);
151     }
152     if (mask & USBSTS_PCD) {
153         trace_usb_ehci_usbsts("PCD", state);
154     }
155     if (mask & USBSTS_FLR) {
156         trace_usb_ehci_usbsts("FLR", state);
157     }
158     if (mask & USBSTS_HSE) {
159         trace_usb_ehci_usbsts("HSE", state);
160     }
161     if (mask & USBSTS_IAA) {
162         trace_usb_ehci_usbsts("IAA", state);
163     }
164 
165     /* status */
166     if (mask & USBSTS_HALT) {
167         trace_usb_ehci_usbsts("HALT", state);
168     }
169     if (mask & USBSTS_REC) {
170         trace_usb_ehci_usbsts("REC", state);
171     }
172     if (mask & USBSTS_PSS) {
173         trace_usb_ehci_usbsts("PSS", state);
174     }
175     if (mask & USBSTS_ASS) {
176         trace_usb_ehci_usbsts("ASS", state);
177     }
178 }
179 
180 static inline void ehci_set_usbsts(EHCIState *s, int mask)
181 {
182     if ((s->usbsts & mask) == mask) {
183         return;
184     }
185     ehci_trace_usbsts(mask, 1);
186     s->usbsts |= mask;
187 }
188 
189 static inline void ehci_clear_usbsts(EHCIState *s, int mask)
190 {
191     if ((s->usbsts & mask) == 0) {
192         return;
193     }
194     ehci_trace_usbsts(mask, 0);
195     s->usbsts &= ~mask;
196 }
197 
198 /* update irq line */
199 static inline void ehci_update_irq(EHCIState *s)
200 {
201     int level = 0;
202 
203     if ((s->usbsts & USBINTR_MASK) & s->usbintr) {
204         level = 1;
205     }
206 
207     trace_usb_ehci_irq(level, s->frindex, s->usbsts, s->usbintr);
208     qemu_set_irq(s->irq, level);
209 }
210 
211 /* flag interrupt condition */
212 static inline void ehci_raise_irq(EHCIState *s, int intr)
213 {
214     if (intr & (USBSTS_PCD | USBSTS_FLR | USBSTS_HSE)) {
215         s->usbsts |= intr;
216         ehci_update_irq(s);
217     } else {
218         s->usbsts_pending |= intr;
219     }
220 }
221 
222 /*
223  * Commit pending interrupts (added via ehci_raise_irq),
224  * at the rate allowed by "Interrupt Threshold Control".
225  */
226 static inline void ehci_commit_irq(EHCIState *s)
227 {
228     uint32_t itc;
229 
230     if (!s->usbsts_pending) {
231         return;
232     }
233     if (s->usbsts_frindex > s->frindex) {
234         return;
235     }
236 
237     itc = (s->usbcmd >> 16) & 0xff;
238     s->usbsts |= s->usbsts_pending;
239     s->usbsts_pending = 0;
240     s->usbsts_frindex = s->frindex + itc;
241     ehci_update_irq(s);
242 }
243 
244 static void ehci_update_halt(EHCIState *s)
245 {
246     if (s->usbcmd & USBCMD_RUNSTOP) {
247         ehci_clear_usbsts(s, USBSTS_HALT);
248     } else {
249         if (s->astate == EST_INACTIVE && s->pstate == EST_INACTIVE) {
250             ehci_set_usbsts(s, USBSTS_HALT);
251         }
252     }
253 }
254 
255 static void ehci_set_state(EHCIState *s, int async, int state)
256 {
257     if (async) {
258         trace_usb_ehci_state("async", state2str(state));
259         s->astate = state;
260         if (s->astate == EST_INACTIVE) {
261             ehci_clear_usbsts(s, USBSTS_ASS);
262             ehci_update_halt(s);
263         } else {
264             ehci_set_usbsts(s, USBSTS_ASS);
265         }
266     } else {
267         trace_usb_ehci_state("periodic", state2str(state));
268         s->pstate = state;
269         if (s->pstate == EST_INACTIVE) {
270             ehci_clear_usbsts(s, USBSTS_PSS);
271             ehci_update_halt(s);
272         } else {
273             ehci_set_usbsts(s, USBSTS_PSS);
274         }
275     }
276 }
277 
278 static int ehci_get_state(EHCIState *s, int async)
279 {
280     return async ? s->astate : s->pstate;
281 }
282 
283 static void ehci_set_fetch_addr(EHCIState *s, int async, uint32_t addr)
284 {
285     if (async) {
286         s->a_fetch_addr = addr;
287     } else {
288         s->p_fetch_addr = addr;
289     }
290 }
291 
292 static int ehci_get_fetch_addr(EHCIState *s, int async)
293 {
294     return async ? s->a_fetch_addr : s->p_fetch_addr;
295 }
296 
297 static void ehci_trace_qh(EHCIQueue *q, hwaddr addr, EHCIqh *qh)
298 {
299     /* need three here due to argument count limits */
300     trace_usb_ehci_qh_ptrs(q, addr, qh->next,
301                            qh->current_qtd, qh->next_qtd, qh->altnext_qtd);
302     trace_usb_ehci_qh_fields(addr,
303                              get_field(qh->epchar, QH_EPCHAR_RL),
304                              get_field(qh->epchar, QH_EPCHAR_MPLEN),
305                              get_field(qh->epchar, QH_EPCHAR_EPS),
306                              get_field(qh->epchar, QH_EPCHAR_EP),
307                              get_field(qh->epchar, QH_EPCHAR_DEVADDR));
308     trace_usb_ehci_qh_bits(addr,
309                            (bool)(qh->epchar & QH_EPCHAR_C),
310                            (bool)(qh->epchar & QH_EPCHAR_H),
311                            (bool)(qh->epchar & QH_EPCHAR_DTC),
312                            (bool)(qh->epchar & QH_EPCHAR_I));
313 }
314 
315 static void ehci_trace_qtd(EHCIQueue *q, hwaddr addr, EHCIqtd *qtd)
316 {
317     /* need three here due to argument count limits */
318     trace_usb_ehci_qtd_ptrs(q, addr, qtd->next, qtd->altnext);
319     trace_usb_ehci_qtd_fields(addr,
320                               get_field(qtd->token, QTD_TOKEN_TBYTES),
321                               get_field(qtd->token, QTD_TOKEN_CPAGE),
322                               get_field(qtd->token, QTD_TOKEN_CERR),
323                               get_field(qtd->token, QTD_TOKEN_PID));
324     trace_usb_ehci_qtd_bits(addr,
325                             (bool)(qtd->token & QTD_TOKEN_IOC),
326                             (bool)(qtd->token & QTD_TOKEN_ACTIVE),
327                             (bool)(qtd->token & QTD_TOKEN_HALT),
328                             (bool)(qtd->token & QTD_TOKEN_BABBLE),
329                             (bool)(qtd->token & QTD_TOKEN_XACTERR));
330 }
331 
332 static void ehci_trace_itd(EHCIState *s, hwaddr addr, EHCIitd *itd)
333 {
334     trace_usb_ehci_itd(addr, itd->next,
335                        get_field(itd->bufptr[1], ITD_BUFPTR_MAXPKT),
336                        get_field(itd->bufptr[2], ITD_BUFPTR_MULT),
337                        get_field(itd->bufptr[0], ITD_BUFPTR_EP),
338                        get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR));
339 }
340 
341 static void ehci_trace_sitd(EHCIState *s, hwaddr addr,
342                             EHCIsitd *sitd)
343 {
344     trace_usb_ehci_sitd(addr, sitd->next,
345                         (bool)(sitd->results & SITD_RESULTS_ACTIVE));
346 }
347 
348 static void ehci_trace_guest_bug(EHCIState *s, const char *message)
349 {
350     trace_usb_ehci_guest_bug(message);
351     fprintf(stderr, "ehci warning: %s\n", message);
352 }
353 
354 static inline bool ehci_enabled(EHCIState *s)
355 {
356     return s->usbcmd & USBCMD_RUNSTOP;
357 }
358 
359 static inline bool ehci_async_enabled(EHCIState *s)
360 {
361     return ehci_enabled(s) && (s->usbcmd & USBCMD_ASE);
362 }
363 
364 static inline bool ehci_periodic_enabled(EHCIState *s)
365 {
366     return ehci_enabled(s) && (s->usbcmd & USBCMD_PSE);
367 }
368 
369 /* Get an array of dwords from main memory */
370 static inline int get_dwords(EHCIState *ehci, uint32_t addr,
371                              uint32_t *buf, int num)
372 {
373     int i;
374 
375     if (!ehci->as) {
376         ehci_raise_irq(ehci, USBSTS_HSE);
377         ehci->usbcmd &= ~USBCMD_RUNSTOP;
378         trace_usb_ehci_dma_error();
379         return -1;
380     }
381 
382     for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
383         dma_memory_read(ehci->as, addr, buf, sizeof(*buf));
384         *buf = le32_to_cpu(*buf);
385     }
386 
387     return num;
388 }
389 
390 /* Put an array of dwords in to main memory */
391 static inline int put_dwords(EHCIState *ehci, uint32_t addr,
392                              uint32_t *buf, int num)
393 {
394     int i;
395 
396     if (!ehci->as) {
397         ehci_raise_irq(ehci, USBSTS_HSE);
398         ehci->usbcmd &= ~USBCMD_RUNSTOP;
399         trace_usb_ehci_dma_error();
400         return -1;
401     }
402 
403     for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
404         uint32_t tmp = cpu_to_le32(*buf);
405         dma_memory_write(ehci->as, addr, &tmp, sizeof(tmp));
406     }
407 
408     return num;
409 }
410 
411 static int ehci_get_pid(EHCIqtd *qtd)
412 {
413     switch (get_field(qtd->token, QTD_TOKEN_PID)) {
414     case 0:
415         return USB_TOKEN_OUT;
416     case 1:
417         return USB_TOKEN_IN;
418     case 2:
419         return USB_TOKEN_SETUP;
420     default:
421         fprintf(stderr, "bad token\n");
422         return 0;
423     }
424 }
425 
426 static bool ehci_verify_qh(EHCIQueue *q, EHCIqh *qh)
427 {
428     uint32_t devaddr = get_field(qh->epchar, QH_EPCHAR_DEVADDR);
429     uint32_t endp    = get_field(qh->epchar, QH_EPCHAR_EP);
430     if ((devaddr != get_field(q->qh.epchar, QH_EPCHAR_DEVADDR)) ||
431         (endp    != get_field(q->qh.epchar, QH_EPCHAR_EP)) ||
432         (qh->current_qtd != q->qh.current_qtd) ||
433         (q->async && qh->next_qtd != q->qh.next_qtd) ||
434         (memcmp(&qh->altnext_qtd, &q->qh.altnext_qtd,
435                                  7 * sizeof(uint32_t)) != 0) ||
436         (q->dev != NULL && q->dev->addr != devaddr)) {
437         return false;
438     } else {
439         return true;
440     }
441 }
442 
443 static bool ehci_verify_qtd(EHCIPacket *p, EHCIqtd *qtd)
444 {
445     if (p->qtdaddr != p->queue->qtdaddr ||
446         (p->queue->async && !NLPTR_TBIT(p->qtd.next) &&
447             (p->qtd.next != qtd->next)) ||
448         (!NLPTR_TBIT(p->qtd.altnext) && (p->qtd.altnext != qtd->altnext)) ||
449         p->qtd.token != qtd->token ||
450         p->qtd.bufptr[0] != qtd->bufptr[0]) {
451         return false;
452     } else {
453         return true;
454     }
455 }
456 
457 static bool ehci_verify_pid(EHCIQueue *q, EHCIqtd *qtd)
458 {
459     int ep  = get_field(q->qh.epchar, QH_EPCHAR_EP);
460     int pid = ehci_get_pid(qtd);
461 
462     /* Note the pid changing is normal for ep 0 (the control ep) */
463     if (q->last_pid && ep != 0 && pid != q->last_pid) {
464         return false;
465     } else {
466         return true;
467     }
468 }
469 
470 /* Finish executing and writeback a packet outside of the regular
471    fetchqh -> fetchqtd -> execute -> writeback cycle */
472 static void ehci_writeback_async_complete_packet(EHCIPacket *p)
473 {
474     EHCIQueue *q = p->queue;
475     EHCIqtd qtd;
476     EHCIqh qh;
477     int state;
478 
479     /* Verify the qh + qtd, like we do when going through fetchqh & fetchqtd */
480     get_dwords(q->ehci, NLPTR_GET(q->qhaddr),
481                (uint32_t *) &qh, sizeof(EHCIqh) >> 2);
482     get_dwords(q->ehci, NLPTR_GET(q->qtdaddr),
483                (uint32_t *) &qtd, sizeof(EHCIqtd) >> 2);
484     if (!ehci_verify_qh(q, &qh) || !ehci_verify_qtd(p, &qtd)) {
485         p->async = EHCI_ASYNC_INITIALIZED;
486         ehci_free_packet(p);
487         return;
488     }
489 
490     state = ehci_get_state(q->ehci, q->async);
491     ehci_state_executing(q);
492     ehci_state_writeback(q); /* Frees the packet! */
493     if (!(q->qh.token & QTD_TOKEN_HALT)) {
494         ehci_state_advqueue(q);
495     }
496     ehci_set_state(q->ehci, q->async, state);
497 }
498 
499 /* packet management */
500 
501 static EHCIPacket *ehci_alloc_packet(EHCIQueue *q)
502 {
503     EHCIPacket *p;
504 
505     p = g_new0(EHCIPacket, 1);
506     p->queue = q;
507     usb_packet_init(&p->packet);
508     QTAILQ_INSERT_TAIL(&q->packets, p, next);
509     trace_usb_ehci_packet_action(p->queue, p, "alloc");
510     return p;
511 }
512 
513 static void ehci_free_packet(EHCIPacket *p)
514 {
515     if (p->async == EHCI_ASYNC_FINISHED &&
516             !(p->queue->qh.token & QTD_TOKEN_HALT)) {
517         ehci_writeback_async_complete_packet(p);
518         return;
519     }
520     trace_usb_ehci_packet_action(p->queue, p, "free");
521     if (p->async == EHCI_ASYNC_INFLIGHT) {
522         usb_cancel_packet(&p->packet);
523     }
524     if (p->async == EHCI_ASYNC_FINISHED &&
525             p->packet.status == USB_RET_SUCCESS) {
526         fprintf(stderr,
527                 "EHCI: Dropping completed packet from halted %s ep %02X\n",
528                 (p->pid == USB_TOKEN_IN) ? "in" : "out",
529                 get_field(p->queue->qh.epchar, QH_EPCHAR_EP));
530     }
531     if (p->async != EHCI_ASYNC_NONE) {
532         usb_packet_unmap(&p->packet, &p->sgl);
533         qemu_sglist_destroy(&p->sgl);
534     }
535     QTAILQ_REMOVE(&p->queue->packets, p, next);
536     usb_packet_cleanup(&p->packet);
537     g_free(p);
538 }
539 
540 /* queue management */
541 
542 static EHCIQueue *ehci_alloc_queue(EHCIState *ehci, uint32_t addr, int async)
543 {
544     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
545     EHCIQueue *q;
546 
547     q = g_malloc0(sizeof(*q));
548     q->ehci = ehci;
549     q->qhaddr = addr;
550     q->async = async;
551     QTAILQ_INIT(&q->packets);
552     QTAILQ_INSERT_HEAD(head, q, next);
553     trace_usb_ehci_queue_action(q, "alloc");
554     return q;
555 }
556 
557 static void ehci_queue_stopped(EHCIQueue *q)
558 {
559     int endp  = get_field(q->qh.epchar, QH_EPCHAR_EP);
560 
561     if (!q->last_pid || !q->dev) {
562         return;
563     }
564 
565     usb_device_ep_stopped(q->dev, usb_ep_get(q->dev, q->last_pid, endp));
566 }
567 
568 static int ehci_cancel_queue(EHCIQueue *q)
569 {
570     EHCIPacket *p;
571     int packets = 0;
572 
573     p = QTAILQ_FIRST(&q->packets);
574     if (p == NULL) {
575         goto leave;
576     }
577 
578     trace_usb_ehci_queue_action(q, "cancel");
579     do {
580         ehci_free_packet(p);
581         packets++;
582     } while ((p = QTAILQ_FIRST(&q->packets)) != NULL);
583 
584 leave:
585     ehci_queue_stopped(q);
586     return packets;
587 }
588 
589 static int ehci_reset_queue(EHCIQueue *q)
590 {
591     int packets;
592 
593     trace_usb_ehci_queue_action(q, "reset");
594     packets = ehci_cancel_queue(q);
595     q->dev = NULL;
596     q->qtdaddr = 0;
597     q->last_pid = 0;
598     return packets;
599 }
600 
601 static void ehci_free_queue(EHCIQueue *q, const char *warn)
602 {
603     EHCIQueueHead *head = q->async ? &q->ehci->aqueues : &q->ehci->pqueues;
604     int cancelled;
605 
606     trace_usb_ehci_queue_action(q, "free");
607     cancelled = ehci_cancel_queue(q);
608     if (warn && cancelled > 0) {
609         ehci_trace_guest_bug(q->ehci, warn);
610     }
611     QTAILQ_REMOVE(head, q, next);
612     g_free(q);
613 }
614 
615 static EHCIQueue *ehci_find_queue_by_qh(EHCIState *ehci, uint32_t addr,
616                                         int async)
617 {
618     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
619     EHCIQueue *q;
620 
621     QTAILQ_FOREACH(q, head, next) {
622         if (addr == q->qhaddr) {
623             return q;
624         }
625     }
626     return NULL;
627 }
628 
629 static void ehci_queues_rip_unused(EHCIState *ehci, int async)
630 {
631     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
632     const char *warn = async ? "guest unlinked busy QH" : NULL;
633     uint64_t maxage = FRAME_TIMER_NS * ehci->maxframes * 4;
634     EHCIQueue *q, *tmp;
635 
636     QTAILQ_FOREACH_SAFE(q, head, next, tmp) {
637         if (q->seen) {
638             q->seen = 0;
639             q->ts = ehci->last_run_ns;
640             continue;
641         }
642         if (ehci->last_run_ns < q->ts + maxage) {
643             continue;
644         }
645         ehci_free_queue(q, warn);
646     }
647 }
648 
649 static void ehci_queues_rip_unseen(EHCIState *ehci, int async)
650 {
651     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
652     EHCIQueue *q, *tmp;
653 
654     QTAILQ_FOREACH_SAFE(q, head, next, tmp) {
655         if (!q->seen) {
656             ehci_free_queue(q, NULL);
657         }
658     }
659 }
660 
661 static void ehci_queues_rip_device(EHCIState *ehci, USBDevice *dev, int async)
662 {
663     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
664     EHCIQueue *q, *tmp;
665 
666     QTAILQ_FOREACH_SAFE(q, head, next, tmp) {
667         if (q->dev != dev) {
668             continue;
669         }
670         ehci_free_queue(q, NULL);
671     }
672 }
673 
674 static void ehci_queues_rip_all(EHCIState *ehci, int async)
675 {
676     EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;
677     const char *warn = async ? "guest stopped busy async schedule" : NULL;
678     EHCIQueue *q, *tmp;
679 
680     QTAILQ_FOREACH_SAFE(q, head, next, tmp) {
681         ehci_free_queue(q, warn);
682     }
683 }
684 
685 /* Attach or detach a device on root hub */
686 
687 static void ehci_attach(USBPort *port)
688 {
689     EHCIState *s = port->opaque;
690     uint32_t *portsc = &s->portsc[port->index];
691     const char *owner = (*portsc & PORTSC_POWNER) ? "comp" : "ehci";
692 
693     trace_usb_ehci_port_attach(port->index, owner, port->dev->product_desc);
694 
695     if (*portsc & PORTSC_POWNER) {
696         USBPort *companion = s->companion_ports[port->index];
697         companion->dev = port->dev;
698         companion->ops->attach(companion);
699         return;
700     }
701 
702     *portsc |= PORTSC_CONNECT;
703     *portsc |= PORTSC_CSC;
704 
705     ehci_raise_irq(s, USBSTS_PCD);
706 }
707 
708 static void ehci_detach(USBPort *port)
709 {
710     EHCIState *s = port->opaque;
711     uint32_t *portsc = &s->portsc[port->index];
712     const char *owner = (*portsc & PORTSC_POWNER) ? "comp" : "ehci";
713 
714     trace_usb_ehci_port_detach(port->index, owner);
715 
716     if (*portsc & PORTSC_POWNER) {
717         USBPort *companion = s->companion_ports[port->index];
718         companion->ops->detach(companion);
719         companion->dev = NULL;
720         /*
721          * EHCI spec 4.2.2: "When a disconnect occurs... On the event,
722          * the port ownership is returned immediately to the EHCI controller."
723          */
724         *portsc &= ~PORTSC_POWNER;
725         return;
726     }
727 
728     ehci_queues_rip_device(s, port->dev, 0);
729     ehci_queues_rip_device(s, port->dev, 1);
730 
731     *portsc &= ~(PORTSC_CONNECT|PORTSC_PED|PORTSC_SUSPEND);
732     *portsc |= PORTSC_CSC;
733 
734     ehci_raise_irq(s, USBSTS_PCD);
735 }
736 
737 static void ehci_child_detach(USBPort *port, USBDevice *child)
738 {
739     EHCIState *s = port->opaque;
740     uint32_t portsc = s->portsc[port->index];
741 
742     if (portsc & PORTSC_POWNER) {
743         USBPort *companion = s->companion_ports[port->index];
744         companion->ops->child_detach(companion, child);
745         return;
746     }
747 
748     ehci_queues_rip_device(s, child, 0);
749     ehci_queues_rip_device(s, child, 1);
750 }
751 
752 static void ehci_wakeup(USBPort *port)
753 {
754     EHCIState *s = port->opaque;
755     uint32_t *portsc = &s->portsc[port->index];
756 
757     if (*portsc & PORTSC_POWNER) {
758         USBPort *companion = s->companion_ports[port->index];
759         if (companion->ops->wakeup) {
760             companion->ops->wakeup(companion);
761         }
762         return;
763     }
764 
765     if (*portsc & PORTSC_SUSPEND) {
766         trace_usb_ehci_port_wakeup(port->index);
767         *portsc |= PORTSC_FPRES;
768         ehci_raise_irq(s, USBSTS_PCD);
769     }
770 
771     qemu_bh_schedule(s->async_bh);
772 }
773 
774 static void ehci_register_companion(USBBus *bus, USBPort *ports[],
775                                     uint32_t portcount, uint32_t firstport,
776                                     Error **errp)
777 {
778     EHCIState *s = container_of(bus, EHCIState, bus);
779     uint32_t i;
780 
781     if (firstport + portcount > NB_PORTS) {
782         error_setg(errp, "firstport must be between 0 and %u",
783                    NB_PORTS - portcount);
784         return;
785     }
786 
787     for (i = 0; i < portcount; i++) {
788         if (s->companion_ports[firstport + i]) {
789             error_setg(errp, "firstport %u asks for ports %u-%u,"
790                        " but port %u has a companion assigned already",
791                        firstport, firstport, firstport + portcount - 1,
792                        firstport + i);
793             return;
794         }
795     }
796 
797     for (i = 0; i < portcount; i++) {
798         s->companion_ports[firstport + i] = ports[i];
799         s->ports[firstport + i].speedmask |=
800             USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL;
801         /* Ensure devs attached before the initial reset go to the companion */
802         s->portsc[firstport + i] = PORTSC_POWNER;
803     }
804 
805     s->companion_count++;
806     s->caps[0x05] = (s->companion_count << 4) | portcount;
807 }
808 
809 static void ehci_wakeup_endpoint(USBBus *bus, USBEndpoint *ep,
810                                  unsigned int stream)
811 {
812     EHCIState *s = container_of(bus, EHCIState, bus);
813     uint32_t portsc = s->portsc[ep->dev->port->index];
814 
815     if (portsc & PORTSC_POWNER) {
816         return;
817     }
818 
819     s->periodic_sched_active = PERIODIC_ACTIVE;
820     qemu_bh_schedule(s->async_bh);
821 }
822 
823 static USBDevice *ehci_find_device(EHCIState *ehci, uint8_t addr)
824 {
825     USBDevice *dev;
826     USBPort *port;
827     int i;
828 
829     for (i = 0; i < NB_PORTS; i++) {
830         port = &ehci->ports[i];
831         if (!(ehci->portsc[i] & PORTSC_PED)) {
832             DPRINTF("Port %d not enabled\n", i);
833             continue;
834         }
835         dev = usb_find_device(port, addr);
836         if (dev != NULL) {
837             return dev;
838         }
839     }
840     return NULL;
841 }
842 
843 /* 4.1 host controller initialization */
844 void ehci_reset(void *opaque)
845 {
846     EHCIState *s = opaque;
847     int i;
848     USBDevice *devs[NB_PORTS];
849 
850     trace_usb_ehci_reset();
851 
852     /*
853      * Do the detach before touching portsc, so that it correctly gets send to
854      * us or to our companion based on PORTSC_POWNER before the reset.
855      */
856     for(i = 0; i < NB_PORTS; i++) {
857         devs[i] = s->ports[i].dev;
858         if (devs[i] && devs[i]->attached) {
859             usb_detach(&s->ports[i]);
860         }
861     }
862 
863     memset(&s->opreg, 0x00, sizeof(s->opreg));
864     memset(&s->portsc, 0x00, sizeof(s->portsc));
865 
866     s->usbcmd = NB_MAXINTRATE << USBCMD_ITC_SH;
867     s->usbsts = USBSTS_HALT;
868     s->usbsts_pending = 0;
869     s->usbsts_frindex = 0;
870     ehci_update_irq(s);
871 
872     s->astate = EST_INACTIVE;
873     s->pstate = EST_INACTIVE;
874 
875     for(i = 0; i < NB_PORTS; i++) {
876         if (s->companion_ports[i]) {
877             s->portsc[i] = PORTSC_POWNER | PORTSC_PPOWER;
878         } else {
879             s->portsc[i] = PORTSC_PPOWER;
880         }
881         if (devs[i] && devs[i]->attached) {
882             usb_attach(&s->ports[i]);
883             usb_device_reset(devs[i]);
884         }
885     }
886     ehci_queues_rip_all(s, 0);
887     ehci_queues_rip_all(s, 1);
888     timer_del(s->frame_timer);
889     qemu_bh_cancel(s->async_bh);
890 }
891 
892 static uint64_t ehci_caps_read(void *ptr, hwaddr addr,
893                                unsigned size)
894 {
895     EHCIState *s = ptr;
896     return s->caps[addr];
897 }
898 
899 static void ehci_caps_write(void *ptr, hwaddr addr,
900                              uint64_t val, unsigned size)
901 {
902 }
903 
904 static uint64_t ehci_opreg_read(void *ptr, hwaddr addr,
905                                 unsigned size)
906 {
907     EHCIState *s = ptr;
908     uint32_t val;
909 
910     switch (addr) {
911     case FRINDEX:
912         /* Round down to mult of 8, else it can go backwards on migration */
913         val = s->frindex & ~7;
914         break;
915     default:
916         val = s->opreg[addr >> 2];
917     }
918 
919     trace_usb_ehci_opreg_read(addr + s->opregbase, addr2str(addr), val);
920     return val;
921 }
922 
923 static uint64_t ehci_port_read(void *ptr, hwaddr addr,
924                                unsigned size)
925 {
926     EHCIState *s = ptr;
927     uint32_t val;
928 
929     val = s->portsc[addr >> 2];
930     trace_usb_ehci_portsc_read(addr + s->portscbase, addr >> 2, val);
931     return val;
932 }
933 
934 static void handle_port_owner_write(EHCIState *s, int port, uint32_t owner)
935 {
936     USBDevice *dev = s->ports[port].dev;
937     uint32_t *portsc = &s->portsc[port];
938     uint32_t orig;
939 
940     if (s->companion_ports[port] == NULL)
941         return;
942 
943     owner = owner & PORTSC_POWNER;
944     orig  = *portsc & PORTSC_POWNER;
945 
946     if (!(owner ^ orig)) {
947         return;
948     }
949 
950     if (dev && dev->attached) {
951         usb_detach(&s->ports[port]);
952     }
953 
954     *portsc &= ~PORTSC_POWNER;
955     *portsc |= owner;
956 
957     if (dev && dev->attached) {
958         usb_attach(&s->ports[port]);
959     }
960 }
961 
962 static void ehci_port_write(void *ptr, hwaddr addr,
963                             uint64_t val, unsigned size)
964 {
965     EHCIState *s = ptr;
966     int port = addr >> 2;
967     uint32_t *portsc = &s->portsc[port];
968     uint32_t old = *portsc;
969     USBDevice *dev = s->ports[port].dev;
970 
971     trace_usb_ehci_portsc_write(addr + s->portscbase, addr >> 2, val);
972 
973     /* Clear rwc bits */
974     *portsc &= ~(val & PORTSC_RWC_MASK);
975     /* The guest may clear, but not set the PED bit */
976     *portsc &= val | ~PORTSC_PED;
977     /* POWNER is masked out by RO_MASK as it is RO when we've no companion */
978     handle_port_owner_write(s, port, val);
979     /* And finally apply RO_MASK */
980     val &= PORTSC_RO_MASK;
981 
982     if ((val & PORTSC_PRESET) && !(*portsc & PORTSC_PRESET)) {
983         trace_usb_ehci_port_reset(port, 1);
984     }
985 
986     if (!(val & PORTSC_PRESET) &&(*portsc & PORTSC_PRESET)) {
987         trace_usb_ehci_port_reset(port, 0);
988         if (dev && dev->attached) {
989             usb_port_reset(&s->ports[port]);
990             *portsc &= ~PORTSC_CSC;
991         }
992 
993         /*
994          *  Table 2.16 Set the enable bit(and enable bit change) to indicate
995          *  to SW that this port has a high speed device attached
996          */
997         if (dev && dev->attached && (dev->speedmask & USB_SPEED_MASK_HIGH)) {
998             val |= PORTSC_PED;
999         }
1000     }
1001 
1002     if ((val & PORTSC_SUSPEND) && !(*portsc & PORTSC_SUSPEND)) {
1003         trace_usb_ehci_port_suspend(port);
1004     }
1005     if (!(val & PORTSC_FPRES) && (*portsc & PORTSC_FPRES)) {
1006         trace_usb_ehci_port_resume(port);
1007         val &= ~PORTSC_SUSPEND;
1008     }
1009 
1010     *portsc &= ~PORTSC_RO_MASK;
1011     *portsc |= val;
1012     trace_usb_ehci_portsc_change(addr + s->portscbase, addr >> 2, *portsc, old);
1013 }
1014 
1015 static void ehci_opreg_write(void *ptr, hwaddr addr,
1016                              uint64_t val, unsigned size)
1017 {
1018     EHCIState *s = ptr;
1019     uint32_t *mmio = s->opreg + (addr >> 2);
1020     uint32_t old = *mmio;
1021     int i;
1022 
1023     trace_usb_ehci_opreg_write(addr + s->opregbase, addr2str(addr), val);
1024 
1025     switch (addr) {
1026     case USBCMD:
1027         if (val & USBCMD_HCRESET) {
1028             ehci_reset(s);
1029             val = s->usbcmd;
1030             break;
1031         }
1032 
1033         /* not supporting dynamic frame list size at the moment */
1034         if ((val & USBCMD_FLS) && !(s->usbcmd & USBCMD_FLS)) {
1035             fprintf(stderr, "attempt to set frame list size -- value %d\n",
1036                     (int)val & USBCMD_FLS);
1037             val &= ~USBCMD_FLS;
1038         }
1039 
1040         if (val & USBCMD_IAAD) {
1041             /*
1042              * Process IAAD immediately, otherwise the Linux IAAD watchdog may
1043              * trigger and re-use a qh without us seeing the unlink.
1044              */
1045             s->async_stepdown = 0;
1046             qemu_bh_schedule(s->async_bh);
1047             trace_usb_ehci_doorbell_ring();
1048         }
1049 
1050         if (((USBCMD_RUNSTOP | USBCMD_PSE | USBCMD_ASE) & val) !=
1051             ((USBCMD_RUNSTOP | USBCMD_PSE | USBCMD_ASE) & s->usbcmd)) {
1052             if (s->pstate == EST_INACTIVE) {
1053                 SET_LAST_RUN_CLOCK(s);
1054             }
1055             s->usbcmd = val; /* Set usbcmd for ehci_update_halt() */
1056             ehci_update_halt(s);
1057             s->async_stepdown = 0;
1058             qemu_bh_schedule(s->async_bh);
1059         }
1060         break;
1061 
1062     case USBSTS:
1063         val &= USBSTS_RO_MASK;              // bits 6 through 31 are RO
1064         ehci_clear_usbsts(s, val);          // bits 0 through 5 are R/WC
1065         val = s->usbsts;
1066         ehci_update_irq(s);
1067         break;
1068 
1069     case USBINTR:
1070         val &= USBINTR_MASK;
1071         if (ehci_enabled(s) && (USBSTS_FLR & val)) {
1072             qemu_bh_schedule(s->async_bh);
1073         }
1074         break;
1075 
1076     case FRINDEX:
1077         val &= 0x00003fff; /* frindex is 14bits */
1078         s->usbsts_frindex = val;
1079         break;
1080 
1081     case CONFIGFLAG:
1082         val &= 0x1;
1083         if (val) {
1084             for(i = 0; i < NB_PORTS; i++)
1085                 handle_port_owner_write(s, i, 0);
1086         }
1087         break;
1088 
1089     case PERIODICLISTBASE:
1090         if (ehci_periodic_enabled(s)) {
1091             fprintf(stderr,
1092               "ehci: PERIODIC list base register set while periodic schedule\n"
1093               "      is enabled and HC is enabled\n");
1094         }
1095         break;
1096 
1097     case ASYNCLISTADDR:
1098         if (ehci_async_enabled(s)) {
1099             fprintf(stderr,
1100               "ehci: ASYNC list address register set while async schedule\n"
1101               "      is enabled and HC is enabled\n");
1102         }
1103         break;
1104     }
1105 
1106     *mmio = val;
1107     trace_usb_ehci_opreg_change(addr + s->opregbase, addr2str(addr),
1108                                 *mmio, old);
1109 }
1110 
1111 /*
1112  *  Write the qh back to guest physical memory.  This step isn't
1113  *  in the EHCI spec but we need to do it since we don't share
1114  *  physical memory with our guest VM.
1115  *
1116  *  The first three dwords are read-only for the EHCI, so skip them
1117  *  when writing back the qh.
1118  */
1119 static void ehci_flush_qh(EHCIQueue *q)
1120 {
1121     uint32_t *qh = (uint32_t *) &q->qh;
1122     uint32_t dwords = sizeof(EHCIqh) >> 2;
1123     uint32_t addr = NLPTR_GET(q->qhaddr);
1124 
1125     put_dwords(q->ehci, addr + 3 * sizeof(uint32_t), qh + 3, dwords - 3);
1126 }
1127 
1128 // 4.10.2
1129 
1130 static int ehci_qh_do_overlay(EHCIQueue *q)
1131 {
1132     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
1133     int i;
1134     int dtoggle;
1135     int ping;
1136     int eps;
1137     int reload;
1138 
1139     assert(p != NULL);
1140     assert(p->qtdaddr == q->qtdaddr);
1141 
1142     // remember values in fields to preserve in qh after overlay
1143 
1144     dtoggle = q->qh.token & QTD_TOKEN_DTOGGLE;
1145     ping    = q->qh.token & QTD_TOKEN_PING;
1146 
1147     q->qh.current_qtd = p->qtdaddr;
1148     q->qh.next_qtd    = p->qtd.next;
1149     q->qh.altnext_qtd = p->qtd.altnext;
1150     q->qh.token       = p->qtd.token;
1151 
1152 
1153     eps = get_field(q->qh.epchar, QH_EPCHAR_EPS);
1154     if (eps == EHCI_QH_EPS_HIGH) {
1155         q->qh.token &= ~QTD_TOKEN_PING;
1156         q->qh.token |= ping;
1157     }
1158 
1159     reload = get_field(q->qh.epchar, QH_EPCHAR_RL);
1160     set_field(&q->qh.altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
1161 
1162     for (i = 0; i < 5; i++) {
1163         q->qh.bufptr[i] = p->qtd.bufptr[i];
1164     }
1165 
1166     if (!(q->qh.epchar & QH_EPCHAR_DTC)) {
1167         // preserve QH DT bit
1168         q->qh.token &= ~QTD_TOKEN_DTOGGLE;
1169         q->qh.token |= dtoggle;
1170     }
1171 
1172     q->qh.bufptr[1] &= ~BUFPTR_CPROGMASK_MASK;
1173     q->qh.bufptr[2] &= ~BUFPTR_FRAMETAG_MASK;
1174 
1175     ehci_flush_qh(q);
1176 
1177     return 0;
1178 }
1179 
1180 static int ehci_init_transfer(EHCIPacket *p)
1181 {
1182     uint32_t cpage, offset, bytes, plen;
1183     dma_addr_t page;
1184 
1185     cpage  = get_field(p->qtd.token, QTD_TOKEN_CPAGE);
1186     bytes  = get_field(p->qtd.token, QTD_TOKEN_TBYTES);
1187     offset = p->qtd.bufptr[0] & ~QTD_BUFPTR_MASK;
1188     qemu_sglist_init(&p->sgl, p->queue->ehci->device, 5, p->queue->ehci->as);
1189 
1190     while (bytes > 0) {
1191         if (cpage > 4) {
1192             fprintf(stderr, "cpage out of range (%d)\n", cpage);
1193             qemu_sglist_destroy(&p->sgl);
1194             return -1;
1195         }
1196 
1197         page  = p->qtd.bufptr[cpage] & QTD_BUFPTR_MASK;
1198         page += offset;
1199         plen  = bytes;
1200         if (plen > 4096 - offset) {
1201             plen = 4096 - offset;
1202             offset = 0;
1203             cpage++;
1204         }
1205 
1206         qemu_sglist_add(&p->sgl, page, plen);
1207         bytes -= plen;
1208     }
1209     return 0;
1210 }
1211 
1212 static void ehci_finish_transfer(EHCIQueue *q, int len)
1213 {
1214     uint32_t cpage, offset;
1215 
1216     if (len > 0) {
1217         /* update cpage & offset */
1218         cpage  = get_field(q->qh.token, QTD_TOKEN_CPAGE);
1219         offset = q->qh.bufptr[0] & ~QTD_BUFPTR_MASK;
1220 
1221         offset += len;
1222         cpage  += offset >> QTD_BUFPTR_SH;
1223         offset &= ~QTD_BUFPTR_MASK;
1224 
1225         set_field(&q->qh.token, cpage, QTD_TOKEN_CPAGE);
1226         q->qh.bufptr[0] &= QTD_BUFPTR_MASK;
1227         q->qh.bufptr[0] |= offset;
1228     }
1229 }
1230 
1231 static void ehci_async_complete_packet(USBPort *port, USBPacket *packet)
1232 {
1233     EHCIPacket *p;
1234     EHCIState *s = port->opaque;
1235     uint32_t portsc = s->portsc[port->index];
1236 
1237     if (portsc & PORTSC_POWNER) {
1238         USBPort *companion = s->companion_ports[port->index];
1239         companion->ops->complete(companion, packet);
1240         return;
1241     }
1242 
1243     p = container_of(packet, EHCIPacket, packet);
1244     assert(p->async == EHCI_ASYNC_INFLIGHT);
1245 
1246     if (packet->status == USB_RET_REMOVE_FROM_QUEUE) {
1247         trace_usb_ehci_packet_action(p->queue, p, "remove");
1248         ehci_free_packet(p);
1249         return;
1250     }
1251 
1252     trace_usb_ehci_packet_action(p->queue, p, "wakeup");
1253     p->async = EHCI_ASYNC_FINISHED;
1254 
1255     if (!p->queue->async) {
1256         s->periodic_sched_active = PERIODIC_ACTIVE;
1257     }
1258     qemu_bh_schedule(s->async_bh);
1259 }
1260 
1261 static void ehci_execute_complete(EHCIQueue *q)
1262 {
1263     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
1264     uint32_t tbytes;
1265 
1266     assert(p != NULL);
1267     assert(p->qtdaddr == q->qtdaddr);
1268     assert(p->async == EHCI_ASYNC_INITIALIZED ||
1269            p->async == EHCI_ASYNC_FINISHED);
1270 
1271     DPRINTF("execute_complete: qhaddr 0x%x, next 0x%x, qtdaddr 0x%x, "
1272             "status %d, actual_length %d\n",
1273             q->qhaddr, q->qh.next, q->qtdaddr,
1274             p->packet.status, p->packet.actual_length);
1275 
1276     switch (p->packet.status) {
1277     case USB_RET_SUCCESS:
1278         break;
1279     case USB_RET_IOERROR:
1280     case USB_RET_NODEV:
1281         q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_XACTERR);
1282         set_field(&q->qh.token, 0, QTD_TOKEN_CERR);
1283         ehci_raise_irq(q->ehci, USBSTS_ERRINT);
1284         break;
1285     case USB_RET_STALL:
1286         q->qh.token |= QTD_TOKEN_HALT;
1287         ehci_raise_irq(q->ehci, USBSTS_ERRINT);
1288         break;
1289     case USB_RET_NAK:
1290         set_field(&q->qh.altnext_qtd, 0, QH_ALTNEXT_NAKCNT);
1291         return; /* We're not done yet with this transaction */
1292     case USB_RET_BABBLE:
1293         q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_BABBLE);
1294         ehci_raise_irq(q->ehci, USBSTS_ERRINT);
1295         break;
1296     default:
1297         /* should not be triggerable */
1298         fprintf(stderr, "USB invalid response %d\n", p->packet.status);
1299         g_assert_not_reached();
1300         break;
1301     }
1302 
1303     /* TODO check 4.12 for splits */
1304     tbytes = get_field(q->qh.token, QTD_TOKEN_TBYTES);
1305     if (tbytes && p->pid == USB_TOKEN_IN) {
1306         tbytes -= p->packet.actual_length;
1307         if (tbytes) {
1308             /* 4.15.1.2 must raise int on a short input packet */
1309             ehci_raise_irq(q->ehci, USBSTS_INT);
1310             if (q->async) {
1311                 q->ehci->int_req_by_async = true;
1312             }
1313         }
1314     } else {
1315         tbytes = 0;
1316     }
1317     DPRINTF("updating tbytes to %d\n", tbytes);
1318     set_field(&q->qh.token, tbytes, QTD_TOKEN_TBYTES);
1319 
1320     ehci_finish_transfer(q, p->packet.actual_length);
1321     usb_packet_unmap(&p->packet, &p->sgl);
1322     qemu_sglist_destroy(&p->sgl);
1323     p->async = EHCI_ASYNC_NONE;
1324 
1325     q->qh.token ^= QTD_TOKEN_DTOGGLE;
1326     q->qh.token &= ~QTD_TOKEN_ACTIVE;
1327 
1328     if (q->qh.token & QTD_TOKEN_IOC) {
1329         ehci_raise_irq(q->ehci, USBSTS_INT);
1330         if (q->async) {
1331             q->ehci->int_req_by_async = true;
1332         }
1333     }
1334 }
1335 
1336 /* 4.10.3 returns "again" */
1337 static int ehci_execute(EHCIPacket *p, const char *action)
1338 {
1339     USBEndpoint *ep;
1340     int endp;
1341     bool spd;
1342 
1343     assert(p->async == EHCI_ASYNC_NONE ||
1344            p->async == EHCI_ASYNC_INITIALIZED);
1345 
1346     if (!(p->qtd.token & QTD_TOKEN_ACTIVE)) {
1347         fprintf(stderr, "Attempting to execute inactive qtd\n");
1348         return -1;
1349     }
1350 
1351     if (get_field(p->qtd.token, QTD_TOKEN_TBYTES) > BUFF_SIZE) {
1352         ehci_trace_guest_bug(p->queue->ehci,
1353                              "guest requested more bytes than allowed");
1354         return -1;
1355     }
1356 
1357     if (!ehci_verify_pid(p->queue, &p->qtd)) {
1358         ehci_queue_stopped(p->queue); /* Mark the ep in the prev dir stopped */
1359     }
1360     p->pid = ehci_get_pid(&p->qtd);
1361     p->queue->last_pid = p->pid;
1362     endp = get_field(p->queue->qh.epchar, QH_EPCHAR_EP);
1363     ep = usb_ep_get(p->queue->dev, p->pid, endp);
1364 
1365     if (p->async == EHCI_ASYNC_NONE) {
1366         if (ehci_init_transfer(p) != 0) {
1367             return -1;
1368         }
1369 
1370         spd = (p->pid == USB_TOKEN_IN && NLPTR_TBIT(p->qtd.altnext) == 0);
1371         usb_packet_setup(&p->packet, p->pid, ep, 0, p->qtdaddr, spd,
1372                          (p->qtd.token & QTD_TOKEN_IOC) != 0);
1373         usb_packet_map(&p->packet, &p->sgl);
1374         p->async = EHCI_ASYNC_INITIALIZED;
1375     }
1376 
1377     trace_usb_ehci_packet_action(p->queue, p, action);
1378     usb_handle_packet(p->queue->dev, &p->packet);
1379     DPRINTF("submit: qh 0x%x next 0x%x qtd 0x%x pid 0x%x len %zd endp 0x%x "
1380             "status %d actual_length %d\n", p->queue->qhaddr, p->qtd.next,
1381             p->qtdaddr, p->pid, p->packet.iov.size, endp, p->packet.status,
1382             p->packet.actual_length);
1383 
1384     if (p->packet.actual_length > BUFF_SIZE) {
1385         fprintf(stderr, "ret from usb_handle_packet > BUFF_SIZE\n");
1386         return -1;
1387     }
1388 
1389     return 1;
1390 }
1391 
1392 /*  4.7.2
1393  */
1394 
1395 static int ehci_process_itd(EHCIState *ehci,
1396                             EHCIitd *itd,
1397                             uint32_t addr)
1398 {
1399     USBDevice *dev;
1400     USBEndpoint *ep;
1401     uint32_t i, len, pid, dir, devaddr, endp;
1402     uint32_t pg, off, ptr1, ptr2, max, mult;
1403 
1404     ehci->periodic_sched_active = PERIODIC_ACTIVE;
1405 
1406     dir =(itd->bufptr[1] & ITD_BUFPTR_DIRECTION);
1407     devaddr = get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR);
1408     endp = get_field(itd->bufptr[0], ITD_BUFPTR_EP);
1409     max = get_field(itd->bufptr[1], ITD_BUFPTR_MAXPKT);
1410     mult = get_field(itd->bufptr[2], ITD_BUFPTR_MULT);
1411 
1412     for(i = 0; i < 8; i++) {
1413         if (itd->transact[i] & ITD_XACT_ACTIVE) {
1414             pg   = get_field(itd->transact[i], ITD_XACT_PGSEL);
1415             off  = itd->transact[i] & ITD_XACT_OFFSET_MASK;
1416             len  = get_field(itd->transact[i], ITD_XACT_LENGTH);
1417 
1418             if (len > max * mult) {
1419                 len = max * mult;
1420             }
1421             if (len > BUFF_SIZE || pg > 6) {
1422                 return -1;
1423             }
1424 
1425             ptr1 = (itd->bufptr[pg] & ITD_BUFPTR_MASK);
1426             qemu_sglist_init(&ehci->isgl, ehci->device, 2, ehci->as);
1427             if (off + len > 4096) {
1428                 /* transfer crosses page border */
1429                 if (pg == 6) {
1430                     qemu_sglist_destroy(&ehci->isgl);
1431                     return -1;  /* avoid page pg + 1 */
1432                 }
1433                 ptr2 = (itd->bufptr[pg + 1] & ITD_BUFPTR_MASK);
1434                 uint32_t len2 = off + len - 4096;
1435                 uint32_t len1 = len - len2;
1436                 qemu_sglist_add(&ehci->isgl, ptr1 + off, len1);
1437                 qemu_sglist_add(&ehci->isgl, ptr2, len2);
1438             } else {
1439                 qemu_sglist_add(&ehci->isgl, ptr1 + off, len);
1440             }
1441 
1442             pid = dir ? USB_TOKEN_IN : USB_TOKEN_OUT;
1443 
1444             dev = ehci_find_device(ehci, devaddr);
1445             ep = usb_ep_get(dev, pid, endp);
1446             if (ep && ep->type == USB_ENDPOINT_XFER_ISOC) {
1447                 usb_packet_setup(&ehci->ipacket, pid, ep, 0, addr, false,
1448                                  (itd->transact[i] & ITD_XACT_IOC) != 0);
1449                 usb_packet_map(&ehci->ipacket, &ehci->isgl);
1450                 usb_handle_packet(dev, &ehci->ipacket);
1451                 usb_packet_unmap(&ehci->ipacket, &ehci->isgl);
1452             } else {
1453                 DPRINTF("ISOCH: attempt to addess non-iso endpoint\n");
1454                 ehci->ipacket.status = USB_RET_NAK;
1455                 ehci->ipacket.actual_length = 0;
1456             }
1457             qemu_sglist_destroy(&ehci->isgl);
1458 
1459             switch (ehci->ipacket.status) {
1460             case USB_RET_SUCCESS:
1461                 break;
1462             default:
1463                 fprintf(stderr, "Unexpected iso usb result: %d\n",
1464                         ehci->ipacket.status);
1465                 /* Fall through */
1466             case USB_RET_IOERROR:
1467             case USB_RET_NODEV:
1468                 /* 3.3.2: XACTERR is only allowed on IN transactions */
1469                 if (dir) {
1470                     itd->transact[i] |= ITD_XACT_XACTERR;
1471                     ehci_raise_irq(ehci, USBSTS_ERRINT);
1472                 }
1473                 break;
1474             case USB_RET_BABBLE:
1475                 itd->transact[i] |= ITD_XACT_BABBLE;
1476                 ehci_raise_irq(ehci, USBSTS_ERRINT);
1477                 break;
1478             case USB_RET_NAK:
1479                 /* no data for us, so do a zero-length transfer */
1480                 ehci->ipacket.actual_length = 0;
1481                 break;
1482             }
1483             if (!dir) {
1484                 set_field(&itd->transact[i], len - ehci->ipacket.actual_length,
1485                           ITD_XACT_LENGTH); /* OUT */
1486             } else {
1487                 set_field(&itd->transact[i], ehci->ipacket.actual_length,
1488                           ITD_XACT_LENGTH); /* IN */
1489             }
1490             if (itd->transact[i] & ITD_XACT_IOC) {
1491                 ehci_raise_irq(ehci, USBSTS_INT);
1492             }
1493             itd->transact[i] &= ~ITD_XACT_ACTIVE;
1494         }
1495     }
1496     return 0;
1497 }
1498 
1499 
1500 /*  This state is the entry point for asynchronous schedule
1501  *  processing.  Entry here consitutes a EHCI start event state (4.8.5)
1502  */
1503 static int ehci_state_waitlisthead(EHCIState *ehci,  int async)
1504 {
1505     EHCIqh qh;
1506     int i = 0;
1507     int again = 0;
1508     uint32_t entry = ehci->asynclistaddr;
1509 
1510     /* set reclamation flag at start event (4.8.6) */
1511     if (async) {
1512         ehci_set_usbsts(ehci, USBSTS_REC);
1513     }
1514 
1515     ehci_queues_rip_unused(ehci, async);
1516 
1517     /*  Find the head of the list (4.9.1.1) */
1518     for(i = 0; i < MAX_QH; i++) {
1519         if (get_dwords(ehci, NLPTR_GET(entry), (uint32_t *) &qh,
1520                        sizeof(EHCIqh) >> 2) < 0) {
1521             return 0;
1522         }
1523         ehci_trace_qh(NULL, NLPTR_GET(entry), &qh);
1524 
1525         if (qh.epchar & QH_EPCHAR_H) {
1526             if (async) {
1527                 entry |= (NLPTR_TYPE_QH << 1);
1528             }
1529 
1530             ehci_set_fetch_addr(ehci, async, entry);
1531             ehci_set_state(ehci, async, EST_FETCHENTRY);
1532             again = 1;
1533             goto out;
1534         }
1535 
1536         entry = qh.next;
1537         if (entry == ehci->asynclistaddr) {
1538             break;
1539         }
1540     }
1541 
1542     /* no head found for list. */
1543 
1544     ehci_set_state(ehci, async, EST_ACTIVE);
1545 
1546 out:
1547     return again;
1548 }
1549 
1550 
1551 /*  This state is the entry point for periodic schedule processing as
1552  *  well as being a continuation state for async processing.
1553  */
1554 static int ehci_state_fetchentry(EHCIState *ehci, int async)
1555 {
1556     int again = 0;
1557     uint32_t entry = ehci_get_fetch_addr(ehci, async);
1558 
1559     if (NLPTR_TBIT(entry)) {
1560         ehci_set_state(ehci, async, EST_ACTIVE);
1561         goto out;
1562     }
1563 
1564     /* section 4.8, only QH in async schedule */
1565     if (async && (NLPTR_TYPE_GET(entry) != NLPTR_TYPE_QH)) {
1566         fprintf(stderr, "non queue head request in async schedule\n");
1567         return -1;
1568     }
1569 
1570     switch (NLPTR_TYPE_GET(entry)) {
1571     case NLPTR_TYPE_QH:
1572         ehci_set_state(ehci, async, EST_FETCHQH);
1573         again = 1;
1574         break;
1575 
1576     case NLPTR_TYPE_ITD:
1577         ehci_set_state(ehci, async, EST_FETCHITD);
1578         again = 1;
1579         break;
1580 
1581     case NLPTR_TYPE_STITD:
1582         ehci_set_state(ehci, async, EST_FETCHSITD);
1583         again = 1;
1584         break;
1585 
1586     default:
1587         /* TODO: handle FSTN type */
1588         fprintf(stderr, "FETCHENTRY: entry at %X is of type %d "
1589                 "which is not supported yet\n", entry, NLPTR_TYPE_GET(entry));
1590         return -1;
1591     }
1592 
1593 out:
1594     return again;
1595 }
1596 
1597 static EHCIQueue *ehci_state_fetchqh(EHCIState *ehci, int async)
1598 {
1599     uint32_t entry;
1600     EHCIQueue *q;
1601     EHCIqh qh;
1602 
1603     entry = ehci_get_fetch_addr(ehci, async);
1604     q = ehci_find_queue_by_qh(ehci, entry, async);
1605     if (q == NULL) {
1606         q = ehci_alloc_queue(ehci, entry, async);
1607     }
1608 
1609     q->seen++;
1610     if (q->seen > 1) {
1611         /* we are going in circles -- stop processing */
1612         ehci_set_state(ehci, async, EST_ACTIVE);
1613         q = NULL;
1614         goto out;
1615     }
1616 
1617     if (get_dwords(ehci, NLPTR_GET(q->qhaddr),
1618                    (uint32_t *) &qh, sizeof(EHCIqh) >> 2) < 0) {
1619         q = NULL;
1620         goto out;
1621     }
1622     ehci_trace_qh(q, NLPTR_GET(q->qhaddr), &qh);
1623 
1624     /*
1625      * The overlay area of the qh should never be changed by the guest,
1626      * except when idle, in which case the reset is a nop.
1627      */
1628     if (!ehci_verify_qh(q, &qh)) {
1629         if (ehci_reset_queue(q) > 0) {
1630             ehci_trace_guest_bug(ehci, "guest updated active QH");
1631         }
1632     }
1633     q->qh = qh;
1634 
1635     q->transact_ctr = get_field(q->qh.epcap, QH_EPCAP_MULT);
1636     if (q->transact_ctr == 0) { /* Guest bug in some versions of windows */
1637         q->transact_ctr = 4;
1638     }
1639 
1640     if (q->dev == NULL) {
1641         q->dev = ehci_find_device(q->ehci,
1642                                   get_field(q->qh.epchar, QH_EPCHAR_DEVADDR));
1643     }
1644 
1645     if (async && (q->qh.epchar & QH_EPCHAR_H)) {
1646 
1647         /*  EHCI spec version 1.0 Section 4.8.3 & 4.10.1 */
1648         if (ehci->usbsts & USBSTS_REC) {
1649             ehci_clear_usbsts(ehci, USBSTS_REC);
1650         } else {
1651             DPRINTF("FETCHQH:  QH 0x%08x. H-bit set, reclamation status reset"
1652                        " - done processing\n", q->qhaddr);
1653             ehci_set_state(ehci, async, EST_ACTIVE);
1654             q = NULL;
1655             goto out;
1656         }
1657     }
1658 
1659 #if EHCI_DEBUG
1660     if (q->qhaddr != q->qh.next) {
1661     DPRINTF("FETCHQH:  QH 0x%08x (h %x halt %x active %x) next 0x%08x\n",
1662                q->qhaddr,
1663                q->qh.epchar & QH_EPCHAR_H,
1664                q->qh.token & QTD_TOKEN_HALT,
1665                q->qh.token & QTD_TOKEN_ACTIVE,
1666                q->qh.next);
1667     }
1668 #endif
1669 
1670     if (q->qh.token & QTD_TOKEN_HALT) {
1671         ehci_set_state(ehci, async, EST_HORIZONTALQH);
1672 
1673     } else if ((q->qh.token & QTD_TOKEN_ACTIVE) &&
1674                (NLPTR_TBIT(q->qh.current_qtd) == 0)) {
1675         q->qtdaddr = q->qh.current_qtd;
1676         ehci_set_state(ehci, async, EST_FETCHQTD);
1677 
1678     } else {
1679         /*  EHCI spec version 1.0 Section 4.10.2 */
1680         ehci_set_state(ehci, async, EST_ADVANCEQUEUE);
1681     }
1682 
1683 out:
1684     return q;
1685 }
1686 
1687 static int ehci_state_fetchitd(EHCIState *ehci, int async)
1688 {
1689     uint32_t entry;
1690     EHCIitd itd;
1691 
1692     assert(!async);
1693     entry = ehci_get_fetch_addr(ehci, async);
1694 
1695     if (get_dwords(ehci, NLPTR_GET(entry), (uint32_t *) &itd,
1696                    sizeof(EHCIitd) >> 2) < 0) {
1697         return -1;
1698     }
1699     ehci_trace_itd(ehci, entry, &itd);
1700 
1701     if (ehci_process_itd(ehci, &itd, entry) != 0) {
1702         return -1;
1703     }
1704 
1705     put_dwords(ehci, NLPTR_GET(entry), (uint32_t *) &itd,
1706                sizeof(EHCIitd) >> 2);
1707     ehci_set_fetch_addr(ehci, async, itd.next);
1708     ehci_set_state(ehci, async, EST_FETCHENTRY);
1709 
1710     return 1;
1711 }
1712 
1713 static int ehci_state_fetchsitd(EHCIState *ehci, int async)
1714 {
1715     uint32_t entry;
1716     EHCIsitd sitd;
1717 
1718     assert(!async);
1719     entry = ehci_get_fetch_addr(ehci, async);
1720 
1721     if (get_dwords(ehci, NLPTR_GET(entry), (uint32_t *)&sitd,
1722                    sizeof(EHCIsitd) >> 2) < 0) {
1723         return 0;
1724     }
1725     ehci_trace_sitd(ehci, entry, &sitd);
1726 
1727     if (!(sitd.results & SITD_RESULTS_ACTIVE)) {
1728         /* siTD is not active, nothing to do */;
1729     } else {
1730         /* TODO: split transfers are not implemented */
1731         fprintf(stderr, "WARNING: Skipping active siTD\n");
1732     }
1733 
1734     ehci_set_fetch_addr(ehci, async, sitd.next);
1735     ehci_set_state(ehci, async, EST_FETCHENTRY);
1736     return 1;
1737 }
1738 
1739 /* Section 4.10.2 - paragraph 3 */
1740 static int ehci_state_advqueue(EHCIQueue *q)
1741 {
1742 #if 0
1743     /* TO-DO: 4.10.2 - paragraph 2
1744      * if I-bit is set to 1 and QH is not active
1745      * go to horizontal QH
1746      */
1747     if (I-bit set) {
1748         ehci_set_state(ehci, async, EST_HORIZONTALQH);
1749         goto out;
1750     }
1751 #endif
1752 
1753     /*
1754      * want data and alt-next qTD is valid
1755      */
1756     if (((q->qh.token & QTD_TOKEN_TBYTES_MASK) != 0) &&
1757         (NLPTR_TBIT(q->qh.altnext_qtd) == 0)) {
1758         q->qtdaddr = q->qh.altnext_qtd;
1759         ehci_set_state(q->ehci, q->async, EST_FETCHQTD);
1760 
1761     /*
1762      *  next qTD is valid
1763      */
1764     } else if (NLPTR_TBIT(q->qh.next_qtd) == 0) {
1765         q->qtdaddr = q->qh.next_qtd;
1766         ehci_set_state(q->ehci, q->async, EST_FETCHQTD);
1767 
1768     /*
1769      *  no valid qTD, try next QH
1770      */
1771     } else {
1772         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1773     }
1774 
1775     return 1;
1776 }
1777 
1778 /* Section 4.10.2 - paragraph 4 */
1779 static int ehci_state_fetchqtd(EHCIQueue *q)
1780 {
1781     EHCIqtd qtd;
1782     EHCIPacket *p;
1783     int again = 1;
1784 
1785     if (get_dwords(q->ehci, NLPTR_GET(q->qtdaddr), (uint32_t *) &qtd,
1786                    sizeof(EHCIqtd) >> 2) < 0) {
1787         return 0;
1788     }
1789     ehci_trace_qtd(q, NLPTR_GET(q->qtdaddr), &qtd);
1790 
1791     p = QTAILQ_FIRST(&q->packets);
1792     if (p != NULL) {
1793         if (!ehci_verify_qtd(p, &qtd)) {
1794             ehci_cancel_queue(q);
1795             if (qtd.token & QTD_TOKEN_ACTIVE) {
1796                 ehci_trace_guest_bug(q->ehci, "guest updated active qTD");
1797             }
1798             p = NULL;
1799         } else {
1800             p->qtd = qtd;
1801             ehci_qh_do_overlay(q);
1802         }
1803     }
1804 
1805     if (!(qtd.token & QTD_TOKEN_ACTIVE)) {
1806         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1807     } else if (p != NULL) {
1808         switch (p->async) {
1809         case EHCI_ASYNC_NONE:
1810         case EHCI_ASYNC_INITIALIZED:
1811             /* Not yet executed (MULT), or previously nacked (int) packet */
1812             ehci_set_state(q->ehci, q->async, EST_EXECUTE);
1813             break;
1814         case EHCI_ASYNC_INFLIGHT:
1815             /* Check if the guest has added new tds to the queue */
1816             again = ehci_fill_queue(QTAILQ_LAST(&q->packets, pkts_head));
1817             /* Unfinished async handled packet, go horizontal */
1818             ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1819             break;
1820         case EHCI_ASYNC_FINISHED:
1821             /* Complete executing of the packet */
1822             ehci_set_state(q->ehci, q->async, EST_EXECUTING);
1823             break;
1824         }
1825     } else {
1826         p = ehci_alloc_packet(q);
1827         p->qtdaddr = q->qtdaddr;
1828         p->qtd = qtd;
1829         ehci_set_state(q->ehci, q->async, EST_EXECUTE);
1830     }
1831 
1832     return again;
1833 }
1834 
1835 static int ehci_state_horizqh(EHCIQueue *q)
1836 {
1837     int again = 0;
1838 
1839     if (ehci_get_fetch_addr(q->ehci, q->async) != q->qh.next) {
1840         ehci_set_fetch_addr(q->ehci, q->async, q->qh.next);
1841         ehci_set_state(q->ehci, q->async, EST_FETCHENTRY);
1842         again = 1;
1843     } else {
1844         ehci_set_state(q->ehci, q->async, EST_ACTIVE);
1845     }
1846 
1847     return again;
1848 }
1849 
1850 /* Returns "again" */
1851 static int ehci_fill_queue(EHCIPacket *p)
1852 {
1853     USBEndpoint *ep = p->packet.ep;
1854     EHCIQueue *q = p->queue;
1855     EHCIqtd qtd = p->qtd;
1856     uint32_t qtdaddr;
1857 
1858     for (;;) {
1859         if (NLPTR_TBIT(qtd.next) != 0) {
1860             break;
1861         }
1862         qtdaddr = qtd.next;
1863         /*
1864          * Detect circular td lists, Windows creates these, counting on the
1865          * active bit going low after execution to make the queue stop.
1866          */
1867         QTAILQ_FOREACH(p, &q->packets, next) {
1868             if (p->qtdaddr == qtdaddr) {
1869                 goto leave;
1870             }
1871         }
1872         if (get_dwords(q->ehci, NLPTR_GET(qtdaddr),
1873                        (uint32_t *) &qtd, sizeof(EHCIqtd) >> 2) < 0) {
1874             return -1;
1875         }
1876         ehci_trace_qtd(q, NLPTR_GET(qtdaddr), &qtd);
1877         if (!(qtd.token & QTD_TOKEN_ACTIVE)) {
1878             break;
1879         }
1880         if (!ehci_verify_pid(q, &qtd)) {
1881             ehci_trace_guest_bug(q->ehci, "guest queued token with wrong pid");
1882             break;
1883         }
1884         p = ehci_alloc_packet(q);
1885         p->qtdaddr = qtdaddr;
1886         p->qtd = qtd;
1887         if (ehci_execute(p, "queue") == -1) {
1888             return -1;
1889         }
1890         assert(p->packet.status == USB_RET_ASYNC);
1891         p->async = EHCI_ASYNC_INFLIGHT;
1892     }
1893 leave:
1894     usb_device_flush_ep_queue(ep->dev, ep);
1895     return 1;
1896 }
1897 
1898 static int ehci_state_execute(EHCIQueue *q)
1899 {
1900     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
1901     int again = 0;
1902 
1903     assert(p != NULL);
1904     assert(p->qtdaddr == q->qtdaddr);
1905 
1906     if (ehci_qh_do_overlay(q) != 0) {
1907         return -1;
1908     }
1909 
1910     // TODO verify enough time remains in the uframe as in 4.4.1.1
1911     // TODO write back ptr to async list when done or out of time
1912 
1913     /* 4.10.3, bottom of page 82, go horizontal on transaction counter == 0 */
1914     if (!q->async && q->transact_ctr == 0) {
1915         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1916         again = 1;
1917         goto out;
1918     }
1919 
1920     if (q->async) {
1921         ehci_set_usbsts(q->ehci, USBSTS_REC);
1922     }
1923 
1924     again = ehci_execute(p, "process");
1925     if (again == -1) {
1926         goto out;
1927     }
1928     if (p->packet.status == USB_RET_ASYNC) {
1929         ehci_flush_qh(q);
1930         trace_usb_ehci_packet_action(p->queue, p, "async");
1931         p->async = EHCI_ASYNC_INFLIGHT;
1932         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1933         if (q->async) {
1934             again = ehci_fill_queue(p);
1935         } else {
1936             again = 1;
1937         }
1938         goto out;
1939     }
1940 
1941     ehci_set_state(q->ehci, q->async, EST_EXECUTING);
1942     again = 1;
1943 
1944 out:
1945     return again;
1946 }
1947 
1948 static int ehci_state_executing(EHCIQueue *q)
1949 {
1950     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
1951 
1952     assert(p != NULL);
1953     assert(p->qtdaddr == q->qtdaddr);
1954 
1955     ehci_execute_complete(q);
1956 
1957     /* 4.10.3 */
1958     if (!q->async && q->transact_ctr > 0) {
1959         q->transact_ctr--;
1960     }
1961 
1962     /* 4.10.5 */
1963     if (p->packet.status == USB_RET_NAK) {
1964         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
1965     } else {
1966         ehci_set_state(q->ehci, q->async, EST_WRITEBACK);
1967     }
1968 
1969     ehci_flush_qh(q);
1970     return 1;
1971 }
1972 
1973 
1974 static int ehci_state_writeback(EHCIQueue *q)
1975 {
1976     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
1977     uint32_t *qtd, addr;
1978     int again = 0;
1979 
1980     /*  Write back the QTD from the QH area */
1981     assert(p != NULL);
1982     assert(p->qtdaddr == q->qtdaddr);
1983 
1984     ehci_trace_qtd(q, NLPTR_GET(p->qtdaddr), (EHCIqtd *) &q->qh.next_qtd);
1985     qtd = (uint32_t *) &q->qh.next_qtd;
1986     addr = NLPTR_GET(p->qtdaddr);
1987     put_dwords(q->ehci, addr + 2 * sizeof(uint32_t), qtd + 2, 2);
1988     ehci_free_packet(p);
1989 
1990     /*
1991      * EHCI specs say go horizontal here.
1992      *
1993      * We can also advance the queue here for performance reasons.  We
1994      * need to take care to only take that shortcut in case we've
1995      * processed the qtd just written back without errors, i.e. halt
1996      * bit is clear.
1997      */
1998     if (q->qh.token & QTD_TOKEN_HALT) {
1999         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
2000         again = 1;
2001     } else {
2002         ehci_set_state(q->ehci, q->async, EST_ADVANCEQUEUE);
2003         again = 1;
2004     }
2005     return again;
2006 }
2007 
2008 /*
2009  * This is the state machine that is common to both async and periodic
2010  */
2011 
2012 static void ehci_advance_state(EHCIState *ehci, int async)
2013 {
2014     EHCIQueue *q = NULL;
2015     int itd_count = 0;
2016     int again;
2017 
2018     do {
2019         switch(ehci_get_state(ehci, async)) {
2020         case EST_WAITLISTHEAD:
2021             again = ehci_state_waitlisthead(ehci, async);
2022             break;
2023 
2024         case EST_FETCHENTRY:
2025             again = ehci_state_fetchentry(ehci, async);
2026             break;
2027 
2028         case EST_FETCHQH:
2029             q = ehci_state_fetchqh(ehci, async);
2030             if (q != NULL) {
2031                 assert(q->async == async);
2032                 again = 1;
2033             } else {
2034                 again = 0;
2035             }
2036             break;
2037 
2038         case EST_FETCHITD:
2039             again = ehci_state_fetchitd(ehci, async);
2040             itd_count++;
2041             break;
2042 
2043         case EST_FETCHSITD:
2044             again = ehci_state_fetchsitd(ehci, async);
2045             itd_count++;
2046             break;
2047 
2048         case EST_ADVANCEQUEUE:
2049             assert(q != NULL);
2050             again = ehci_state_advqueue(q);
2051             break;
2052 
2053         case EST_FETCHQTD:
2054             assert(q != NULL);
2055             again = ehci_state_fetchqtd(q);
2056             break;
2057 
2058         case EST_HORIZONTALQH:
2059             assert(q != NULL);
2060             again = ehci_state_horizqh(q);
2061             break;
2062 
2063         case EST_EXECUTE:
2064             assert(q != NULL);
2065             again = ehci_state_execute(q);
2066             if (async) {
2067                 ehci->async_stepdown = 0;
2068             }
2069             break;
2070 
2071         case EST_EXECUTING:
2072             assert(q != NULL);
2073             if (async) {
2074                 ehci->async_stepdown = 0;
2075             }
2076             again = ehci_state_executing(q);
2077             break;
2078 
2079         case EST_WRITEBACK:
2080             assert(q != NULL);
2081             again = ehci_state_writeback(q);
2082             if (!async) {
2083                 ehci->periodic_sched_active = PERIODIC_ACTIVE;
2084             }
2085             break;
2086 
2087         default:
2088             fprintf(stderr, "Bad state!\n");
2089             again = -1;
2090             g_assert_not_reached();
2091             break;
2092         }
2093 
2094         if (again < 0 || itd_count > 16) {
2095             /* TODO: notify guest (raise HSE irq?) */
2096             fprintf(stderr, "processing error - resetting ehci HC\n");
2097             ehci_reset(ehci);
2098             again = 0;
2099         }
2100     }
2101     while (again);
2102 }
2103 
2104 static void ehci_advance_async_state(EHCIState *ehci)
2105 {
2106     const int async = 1;
2107 
2108     switch(ehci_get_state(ehci, async)) {
2109     case EST_INACTIVE:
2110         if (!ehci_async_enabled(ehci)) {
2111             break;
2112         }
2113         ehci_set_state(ehci, async, EST_ACTIVE);
2114         // No break, fall through to ACTIVE
2115 
2116     case EST_ACTIVE:
2117         if (!ehci_async_enabled(ehci)) {
2118             ehci_queues_rip_all(ehci, async);
2119             ehci_set_state(ehci, async, EST_INACTIVE);
2120             break;
2121         }
2122 
2123         /* make sure guest has acknowledged the doorbell interrupt */
2124         /* TO-DO: is this really needed? */
2125         if (ehci->usbsts & USBSTS_IAA) {
2126             DPRINTF("IAA status bit still set.\n");
2127             break;
2128         }
2129 
2130         /* check that address register has been set */
2131         if (ehci->asynclistaddr == 0) {
2132             break;
2133         }
2134 
2135         ehci_set_state(ehci, async, EST_WAITLISTHEAD);
2136         ehci_advance_state(ehci, async);
2137 
2138         /* If the doorbell is set, the guest wants to make a change to the
2139          * schedule. The host controller needs to release cached data.
2140          * (section 4.8.2)
2141          */
2142         if (ehci->usbcmd & USBCMD_IAAD) {
2143             /* Remove all unseen qhs from the async qhs queue */
2144             ehci_queues_rip_unseen(ehci, async);
2145             trace_usb_ehci_doorbell_ack();
2146             ehci->usbcmd &= ~USBCMD_IAAD;
2147             ehci_raise_irq(ehci, USBSTS_IAA);
2148         }
2149         break;
2150 
2151     default:
2152         /* this should only be due to a developer mistake */
2153         fprintf(stderr, "ehci: Bad asynchronous state %d. "
2154                 "Resetting to active\n", ehci->astate);
2155         g_assert_not_reached();
2156     }
2157 }
2158 
2159 static void ehci_advance_periodic_state(EHCIState *ehci)
2160 {
2161     uint32_t entry;
2162     uint32_t list;
2163     const int async = 0;
2164 
2165     // 4.6
2166 
2167     switch(ehci_get_state(ehci, async)) {
2168     case EST_INACTIVE:
2169         if (!(ehci->frindex & 7) && ehci_periodic_enabled(ehci)) {
2170             ehci_set_state(ehci, async, EST_ACTIVE);
2171             // No break, fall through to ACTIVE
2172         } else
2173             break;
2174 
2175     case EST_ACTIVE:
2176         if (!(ehci->frindex & 7) && !ehci_periodic_enabled(ehci)) {
2177             ehci_queues_rip_all(ehci, async);
2178             ehci_set_state(ehci, async, EST_INACTIVE);
2179             break;
2180         }
2181 
2182         list = ehci->periodiclistbase & 0xfffff000;
2183         /* check that register has been set */
2184         if (list == 0) {
2185             break;
2186         }
2187         list |= ((ehci->frindex & 0x1ff8) >> 1);
2188 
2189         if (get_dwords(ehci, list, &entry, 1) < 0) {
2190             break;
2191         }
2192 
2193         DPRINTF("PERIODIC state adv fr=%d.  [%08X] -> %08X\n",
2194                 ehci->frindex / 8, list, entry);
2195         ehci_set_fetch_addr(ehci, async,entry);
2196         ehci_set_state(ehci, async, EST_FETCHENTRY);
2197         ehci_advance_state(ehci, async);
2198         ehci_queues_rip_unused(ehci, async);
2199         break;
2200 
2201     default:
2202         /* this should only be due to a developer mistake */
2203         fprintf(stderr, "ehci: Bad periodic state %d. "
2204                 "Resetting to active\n", ehci->pstate);
2205         g_assert_not_reached();
2206     }
2207 }
2208 
2209 static void ehci_update_frindex(EHCIState *ehci, int uframes)
2210 {
2211     if (!ehci_enabled(ehci) && ehci->pstate == EST_INACTIVE) {
2212         return;
2213     }
2214 
2215     /* Generate FLR interrupt if frame index rolls over 0x2000 */
2216     if ((ehci->frindex % 0x2000) + uframes >= 0x2000) {
2217         ehci_raise_irq(ehci, USBSTS_FLR);
2218     }
2219 
2220     /* How many times will frindex roll over 0x4000 with this frame count?
2221      * usbsts_frindex is decremented by 0x4000 on rollover until it reaches 0
2222      */
2223     int rollovers = (ehci->frindex + uframes) / 0x4000;
2224     if (rollovers > 0) {
2225         if (ehci->usbsts_frindex >= (rollovers * 0x4000)) {
2226             ehci->usbsts_frindex -= 0x4000 * rollovers;
2227         } else {
2228             ehci->usbsts_frindex = 0;
2229         }
2230     }
2231 
2232     ehci->frindex = (ehci->frindex + uframes) % 0x4000;
2233 }
2234 
2235 static void ehci_frame_timer(void *opaque)
2236 {
2237     EHCIState *ehci = opaque;
2238     int need_timer = 0;
2239     int64_t expire_time, t_now;
2240     uint64_t ns_elapsed;
2241     int uframes, skipped_uframes;
2242     int i;
2243 
2244     t_now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
2245     ns_elapsed = t_now - ehci->last_run_ns;
2246     uframes = ns_elapsed / UFRAME_TIMER_NS;
2247 
2248     if (ehci_periodic_enabled(ehci) || ehci->pstate != EST_INACTIVE) {
2249         need_timer++;
2250 
2251         if (uframes > (ehci->maxframes * 8)) {
2252             skipped_uframes = uframes - (ehci->maxframes * 8);
2253             ehci_update_frindex(ehci, skipped_uframes);
2254             ehci->last_run_ns += UFRAME_TIMER_NS * skipped_uframes;
2255             uframes -= skipped_uframes;
2256             DPRINTF("WARNING - EHCI skipped %d uframes\n", skipped_uframes);
2257         }
2258 
2259         for (i = 0; i < uframes; i++) {
2260             /*
2261              * If we're running behind schedule, we should not catch up
2262              * too fast, as that will make some guests unhappy:
2263              * 1) We must process a minimum of MIN_UFR_PER_TICK frames,
2264              *    otherwise we will never catch up
2265              * 2) Process frames until the guest has requested an irq (IOC)
2266              */
2267             if (i >= MIN_UFR_PER_TICK) {
2268                 ehci_commit_irq(ehci);
2269                 if ((ehci->usbsts & USBINTR_MASK) & ehci->usbintr) {
2270                     break;
2271                 }
2272             }
2273             if (ehci->periodic_sched_active) {
2274                 ehci->periodic_sched_active--;
2275             }
2276             ehci_update_frindex(ehci, 1);
2277             if ((ehci->frindex & 7) == 0) {
2278                 ehci_advance_periodic_state(ehci);
2279             }
2280             ehci->last_run_ns += UFRAME_TIMER_NS;
2281         }
2282     } else {
2283         ehci->periodic_sched_active = 0;
2284         ehci_update_frindex(ehci, uframes);
2285         ehci->last_run_ns += UFRAME_TIMER_NS * uframes;
2286     }
2287 
2288     if (ehci->periodic_sched_active) {
2289         ehci->async_stepdown = 0;
2290     } else if (ehci->async_stepdown < ehci->maxframes / 2) {
2291         ehci->async_stepdown++;
2292     }
2293 
2294     /*  Async is not inside loop since it executes everything it can once
2295      *  called
2296      */
2297     if (ehci_async_enabled(ehci) || ehci->astate != EST_INACTIVE) {
2298         need_timer++;
2299         ehci_advance_async_state(ehci);
2300     }
2301 
2302     ehci_commit_irq(ehci);
2303     if (ehci->usbsts_pending) {
2304         need_timer++;
2305         ehci->async_stepdown = 0;
2306     }
2307 
2308     if (ehci_enabled(ehci) && (ehci->usbintr & USBSTS_FLR)) {
2309         need_timer++;
2310     }
2311 
2312     if (need_timer) {
2313         /* If we've raised int, we speed up the timer, so that we quickly
2314          * notice any new packets queued up in response */
2315         if (ehci->int_req_by_async && (ehci->usbsts & USBSTS_INT)) {
2316             expire_time = t_now +
2317                 NANOSECONDS_PER_SECOND / (FRAME_TIMER_FREQ * 4);
2318             ehci->int_req_by_async = false;
2319         } else {
2320             expire_time = t_now + (NANOSECONDS_PER_SECOND
2321                                * (ehci->async_stepdown+1) / FRAME_TIMER_FREQ);
2322         }
2323         timer_mod(ehci->frame_timer, expire_time);
2324     }
2325 }
2326 
2327 static const MemoryRegionOps ehci_mmio_caps_ops = {
2328     .read = ehci_caps_read,
2329     .write = ehci_caps_write,
2330     .valid.min_access_size = 1,
2331     .valid.max_access_size = 4,
2332     .impl.min_access_size = 1,
2333     .impl.max_access_size = 1,
2334     .endianness = DEVICE_LITTLE_ENDIAN,
2335 };
2336 
2337 static const MemoryRegionOps ehci_mmio_opreg_ops = {
2338     .read = ehci_opreg_read,
2339     .write = ehci_opreg_write,
2340     .valid.min_access_size = 4,
2341     .valid.max_access_size = 4,
2342     .endianness = DEVICE_LITTLE_ENDIAN,
2343 };
2344 
2345 static const MemoryRegionOps ehci_mmio_port_ops = {
2346     .read = ehci_port_read,
2347     .write = ehci_port_write,
2348     .valid.min_access_size = 4,
2349     .valid.max_access_size = 4,
2350     .endianness = DEVICE_LITTLE_ENDIAN,
2351 };
2352 
2353 static USBPortOps ehci_port_ops = {
2354     .attach = ehci_attach,
2355     .detach = ehci_detach,
2356     .child_detach = ehci_child_detach,
2357     .wakeup = ehci_wakeup,
2358     .complete = ehci_async_complete_packet,
2359 };
2360 
2361 static USBBusOps ehci_bus_ops_companion = {
2362     .register_companion = ehci_register_companion,
2363     .wakeup_endpoint = ehci_wakeup_endpoint,
2364 };
2365 static USBBusOps ehci_bus_ops_standalone = {
2366     .wakeup_endpoint = ehci_wakeup_endpoint,
2367 };
2368 
2369 static void usb_ehci_pre_save(void *opaque)
2370 {
2371     EHCIState *ehci = opaque;
2372     uint32_t new_frindex;
2373 
2374     /* Round down frindex to a multiple of 8 for migration compatibility */
2375     new_frindex = ehci->frindex & ~7;
2376     ehci->last_run_ns -= (ehci->frindex - new_frindex) * UFRAME_TIMER_NS;
2377     ehci->frindex = new_frindex;
2378 }
2379 
2380 static int usb_ehci_post_load(void *opaque, int version_id)
2381 {
2382     EHCIState *s = opaque;
2383     int i;
2384 
2385     for (i = 0; i < NB_PORTS; i++) {
2386         USBPort *companion = s->companion_ports[i];
2387         if (companion == NULL) {
2388             continue;
2389         }
2390         if (s->portsc[i] & PORTSC_POWNER) {
2391             companion->dev = s->ports[i].dev;
2392         } else {
2393             companion->dev = NULL;
2394         }
2395     }
2396 
2397     return 0;
2398 }
2399 
2400 static void usb_ehci_vm_state_change(void *opaque, int running, RunState state)
2401 {
2402     EHCIState *ehci = opaque;
2403 
2404     /*
2405      * We don't migrate the EHCIQueue-s, instead we rebuild them for the
2406      * schedule in guest memory. We must do the rebuilt ASAP, so that
2407      * USB-devices which have async handled packages have a packet in the
2408      * ep queue to match the completion with.
2409      */
2410     if (state == RUN_STATE_RUNNING) {
2411         ehci_advance_async_state(ehci);
2412     }
2413 
2414     /*
2415      * The schedule rebuilt from guest memory could cause the migration dest
2416      * to miss a QH unlink, and fail to cancel packets, since the unlinked QH
2417      * will never have existed on the destination. Therefor we must flush the
2418      * async schedule on savevm to catch any not yet noticed unlinks.
2419      */
2420     if (state == RUN_STATE_SAVE_VM) {
2421         ehci_advance_async_state(ehci);
2422         ehci_queues_rip_unseen(ehci, 1);
2423     }
2424 }
2425 
2426 const VMStateDescription vmstate_ehci = {
2427     .name        = "ehci-core",
2428     .version_id  = 2,
2429     .minimum_version_id  = 1,
2430     .pre_save    = usb_ehci_pre_save,
2431     .post_load   = usb_ehci_post_load,
2432     .fields = (VMStateField[]) {
2433         /* mmio registers */
2434         VMSTATE_UINT32(usbcmd, EHCIState),
2435         VMSTATE_UINT32(usbsts, EHCIState),
2436         VMSTATE_UINT32_V(usbsts_pending, EHCIState, 2),
2437         VMSTATE_UINT32_V(usbsts_frindex, EHCIState, 2),
2438         VMSTATE_UINT32(usbintr, EHCIState),
2439         VMSTATE_UINT32(frindex, EHCIState),
2440         VMSTATE_UINT32(ctrldssegment, EHCIState),
2441         VMSTATE_UINT32(periodiclistbase, EHCIState),
2442         VMSTATE_UINT32(asynclistaddr, EHCIState),
2443         VMSTATE_UINT32(configflag, EHCIState),
2444         VMSTATE_UINT32(portsc[0], EHCIState),
2445         VMSTATE_UINT32(portsc[1], EHCIState),
2446         VMSTATE_UINT32(portsc[2], EHCIState),
2447         VMSTATE_UINT32(portsc[3], EHCIState),
2448         VMSTATE_UINT32(portsc[4], EHCIState),
2449         VMSTATE_UINT32(portsc[5], EHCIState),
2450         /* frame timer */
2451         VMSTATE_TIMER_PTR(frame_timer, EHCIState),
2452         VMSTATE_UINT64(last_run_ns, EHCIState),
2453         VMSTATE_UINT32(async_stepdown, EHCIState),
2454         /* schedule state */
2455         VMSTATE_UINT32(astate, EHCIState),
2456         VMSTATE_UINT32(pstate, EHCIState),
2457         VMSTATE_UINT32(a_fetch_addr, EHCIState),
2458         VMSTATE_UINT32(p_fetch_addr, EHCIState),
2459         VMSTATE_END_OF_LIST()
2460     }
2461 };
2462 
2463 void usb_ehci_realize(EHCIState *s, DeviceState *dev, Error **errp)
2464 {
2465     int i;
2466 
2467     if (s->portnr > NB_PORTS) {
2468         error_setg(errp, "Too many ports! Max. port number is %d.",
2469                    NB_PORTS);
2470         return;
2471     }
2472 
2473     usb_bus_new(&s->bus, sizeof(s->bus), s->companion_enable ?
2474                 &ehci_bus_ops_companion : &ehci_bus_ops_standalone, dev);
2475     for (i = 0; i < s->portnr; i++) {
2476         usb_register_port(&s->bus, &s->ports[i], s, i, &ehci_port_ops,
2477                           USB_SPEED_MASK_HIGH);
2478         s->ports[i].dev = 0;
2479     }
2480 
2481     s->frame_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ehci_frame_timer, s);
2482     s->async_bh = qemu_bh_new(ehci_frame_timer, s);
2483     s->device = dev;
2484 
2485     s->vmstate = qemu_add_vm_change_state_handler(usb_ehci_vm_state_change, s);
2486 }
2487 
2488 void usb_ehci_unrealize(EHCIState *s, DeviceState *dev, Error **errp)
2489 {
2490     trace_usb_ehci_unrealize();
2491 
2492     if (s->frame_timer) {
2493         timer_del(s->frame_timer);
2494         timer_free(s->frame_timer);
2495         s->frame_timer = NULL;
2496     }
2497     if (s->async_bh) {
2498         qemu_bh_delete(s->async_bh);
2499     }
2500 
2501     ehci_queues_rip_all(s, 0);
2502     ehci_queues_rip_all(s, 1);
2503 
2504     memory_region_del_subregion(&s->mem, &s->mem_caps);
2505     memory_region_del_subregion(&s->mem, &s->mem_opreg);
2506     memory_region_del_subregion(&s->mem, &s->mem_ports);
2507 
2508     usb_bus_release(&s->bus);
2509 
2510     if (s->vmstate) {
2511         qemu_del_vm_change_state_handler(s->vmstate);
2512     }
2513 }
2514 
2515 void usb_ehci_init(EHCIState *s, DeviceState *dev)
2516 {
2517     /* 2.2 host controller interface version */
2518     s->caps[0x00] = (uint8_t)(s->opregbase - s->capsbase);
2519     s->caps[0x01] = 0x00;
2520     s->caps[0x02] = 0x00;
2521     s->caps[0x03] = 0x01;        /* HC version */
2522     s->caps[0x04] = s->portnr;   /* Number of downstream ports */
2523     s->caps[0x05] = 0x00;        /* No companion ports at present */
2524     s->caps[0x06] = 0x00;
2525     s->caps[0x07] = 0x00;
2526     s->caps[0x08] = 0x80;        /* We can cache whole frame, no 64-bit */
2527     s->caps[0x0a] = 0x00;
2528     s->caps[0x0b] = 0x00;
2529 
2530     QTAILQ_INIT(&s->aqueues);
2531     QTAILQ_INIT(&s->pqueues);
2532     usb_packet_init(&s->ipacket);
2533 
2534     memory_region_init(&s->mem, OBJECT(dev), "ehci", MMIO_SIZE);
2535     memory_region_init_io(&s->mem_caps, OBJECT(dev), &ehci_mmio_caps_ops, s,
2536                           "capabilities", CAPA_SIZE);
2537     memory_region_init_io(&s->mem_opreg, OBJECT(dev), &ehci_mmio_opreg_ops, s,
2538                           "operational", s->portscbase);
2539     memory_region_init_io(&s->mem_ports, OBJECT(dev), &ehci_mmio_port_ops, s,
2540                           "ports", 4 * s->portnr);
2541 
2542     memory_region_add_subregion(&s->mem, s->capsbase, &s->mem_caps);
2543     memory_region_add_subregion(&s->mem, s->opregbase, &s->mem_opreg);
2544     memory_region_add_subregion(&s->mem, s->opregbase + s->portscbase,
2545                                 &s->mem_ports);
2546 }
2547 
2548 void usb_ehci_finalize(EHCIState *s)
2549 {
2550     usb_packet_cleanup(&s->ipacket);
2551 }
2552 
2553 /*
2554  * vim: expandtab ts=4
2555  */
2556