virtio.c revision 1.19
1/*	$NetBSD: virtio.c,v 1.19 2016/11/29 22:04:42 uwe Exp $	*/
2
3/*
4 * Copyright (c) 2010 Minoura Makoto.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__KERNEL_RCSID(0, "$NetBSD: virtio.c,v 1.19 2016/11/29 22:04:42 uwe Exp $");
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#include <sys/atomic.h>
35#include <sys/bus.h>
36#include <sys/device.h>
37#include <sys/kmem.h>
38#include <sys/module.h>
39
40#include <dev/pci/pcidevs.h>
41#include <dev/pci/pcireg.h>
42#include <dev/pci/pcivar.h>
43
44#include <dev/pci/virtioreg.h>
45#include <dev/pci/virtiovar.h>
46
47#define MINSEG_INDIRECT		2 /* use indirect if nsegs >= this value */
48
49static int	virtio_match(device_t, cfdata_t, void *);
50static void	virtio_attach(device_t, device_t, void *);
51static int	virtio_rescan(device_t, const char *, const int *);
52static int	virtio_detach(device_t, int);
53static int	virtio_intr(void *arg);
54static int	virtio_msix_queue_intr(void *);
55static int	virtio_msix_config_intr(void *);
56static int	virtio_setup_msix_vectors(struct virtio_softc *);
57static int	virtio_setup_msix_interrupts(struct virtio_softc *,
58		    struct pci_attach_args *);
59static int	virtio_setup_intx_interrupt(struct virtio_softc *,
60		    struct pci_attach_args *);
61static int	virtio_setup_interrupts(struct virtio_softc *);
62static void	virtio_soft_intr(void *arg);
63static void	virtio_init_vq(struct virtio_softc *,
64		    struct virtqueue *, const bool);
65
66CFATTACH_DECL3_NEW(virtio, sizeof(struct virtio_softc),
67    virtio_match, virtio_attach, virtio_detach, NULL, virtio_rescan, NULL,
68    DVF_DETACH_SHUTDOWN);
69
70static void
71virtio_set_status(struct virtio_softc *sc, int status)
72{
73	int old = 0;
74
75	if (status != 0)
76		old = bus_space_read_1(sc->sc_iot, sc->sc_ioh,
77				       VIRTIO_CONFIG_DEVICE_STATUS);
78	bus_space_write_1(sc->sc_iot, sc->sc_ioh, VIRTIO_CONFIG_DEVICE_STATUS,
79			  status|old);
80}
81
82#define virtio_device_reset(sc)	virtio_set_status((sc), 0)
83
84static int
85virtio_match(device_t parent, cfdata_t match, void *aux)
86{
87	struct pci_attach_args *pa;
88
89	pa = (struct pci_attach_args *)aux;
90	switch (PCI_VENDOR(pa->pa_id)) {
91	case PCI_VENDOR_QUMRANET:
92		if ((PCI_PRODUCT_QUMRANET_VIRTIO_1000 <=
93		     PCI_PRODUCT(pa->pa_id)) &&
94		    (PCI_PRODUCT(pa->pa_id) <=
95		     PCI_PRODUCT_QUMRANET_VIRTIO_103F))
96			return 1;
97		break;
98	}
99
100	return 0;
101}
102
103static const char *virtio_device_name[] = {
104	"Unknown (0)",			/* 0 */
105	"Network",			/* 1 */
106	"Block",			/* 2 */
107	"Console",			/* 3 */
108	"Entropy",			/* 4 */
109	"Memory Balloon",		/* 5 */
110	"I/O Memory",			/* 6 */
111	"Remote Processor Messaging",	/* 7 */
112	"SCSI",				/* 8 */
113	"9P Transport",			/* 9 */
114	"mac80211 wlan",		/* 10 */
115};
116#define NDEVNAMES	__arraycount(virtio_device_name)
117
118#define VIRTIO_MSIX_CONFIG_VECTOR_INDEX	0
119#define VIRTIO_MSIX_QUEUE_VECTOR_INDEX	1
120
121static int
122virtio_setup_msix_vectors(struct virtio_softc *sc)
123{
124	int offset, vector, ret, qid;
125
126	offset = VIRTIO_CONFIG_MSI_CONFIG_VECTOR;
127	vector = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
128
129	bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, vector);
130	ret = bus_space_read_2(sc->sc_iot, sc->sc_ioh, offset);
131	aprint_debug_dev(sc->sc_dev, "expected=%d, actual=%d\n",
132	    vector, ret);
133	if (ret != vector)
134		return -1;
135
136	for (qid = 0; qid < sc->sc_nvqs; qid++) {
137		offset = VIRTIO_CONFIG_QUEUE_SELECT;
138		bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, qid);
139
140		offset = VIRTIO_CONFIG_MSI_QUEUE_VECTOR;
141		vector = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
142
143		bus_space_write_2(sc->sc_iot, sc->sc_ioh, offset, vector);
144		ret = bus_space_read_2(sc->sc_iot, sc->sc_ioh, offset);
145		aprint_debug_dev(sc->sc_dev, "expected=%d, actual=%d\n",
146		    vector, ret);
147		if (ret != vector)
148			return -1;
149	}
150
151	return 0;
152}
153
154static int
155virtio_setup_msix_interrupts(struct virtio_softc *sc,
156    struct pci_attach_args *pa)
157{
158	device_t self = sc->sc_dev;
159	pci_chipset_tag_t pc = pa->pa_pc;
160	char intrbuf[PCI_INTRSTR_LEN];
161	char const *intrstr;
162	int idx;
163
164	idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
165	if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
166		pci_intr_setattr(pc, &sc->sc_ihp[idx], PCI_INTR_MPSAFE, true);
167
168	sc->sc_ihs[idx] = pci_intr_establish_xname(pc, sc->sc_ihp[idx], IPL_NET,
169	    virtio_msix_config_intr, sc, device_xname(sc->sc_dev));
170	if (sc->sc_ihs[idx] == NULL) {
171		aprint_error_dev(self, "couldn't establish MSI-X for config\n");
172		goto error;
173	}
174
175	idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
176	if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
177		pci_intr_setattr(pc, &sc->sc_ihp[idx], PCI_INTR_MPSAFE, true);
178
179	sc->sc_ihs[idx] = pci_intr_establish_xname(pc, sc->sc_ihp[idx], IPL_NET,
180	    virtio_msix_queue_intr, sc, device_xname(sc->sc_dev));
181	if (sc->sc_ihs[idx] == NULL) {
182		aprint_error_dev(self, "couldn't establish MSI-X for queues\n");
183		goto error;
184	}
185
186	if (virtio_setup_msix_vectors(sc) != 0) {
187		aprint_error_dev(self, "couldn't setup MSI-X vectors\n");
188		goto error;
189	}
190
191	idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
192	intrstr = pci_intr_string(pc, sc->sc_ihp[idx], intrbuf, sizeof(intrbuf));
193	aprint_normal_dev(self, "config interrupting at %s\n", intrstr);
194	idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
195	intrstr = pci_intr_string(pc, sc->sc_ihp[idx], intrbuf, sizeof(intrbuf));
196	aprint_normal_dev(self, "queues interrupting at %s\n", intrstr);
197
198	return 0;
199
200error:
201	idx = VIRTIO_MSIX_CONFIG_VECTOR_INDEX;
202	if (sc->sc_ihs[idx] != NULL)
203		pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[idx]);
204	idx = VIRTIO_MSIX_QUEUE_VECTOR_INDEX;
205	if (sc->sc_ihs[idx] != NULL)
206		pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[idx]);
207
208	return -1;
209}
210
211static int
212virtio_setup_intx_interrupt(struct virtio_softc *sc,
213    struct pci_attach_args *pa)
214{
215	device_t self = sc->sc_dev;
216	pci_chipset_tag_t pc = pa->pa_pc;
217	char intrbuf[PCI_INTRSTR_LEN];
218	char const *intrstr;
219
220	if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
221		pci_intr_setattr(pc, &sc->sc_ihp[0], PCI_INTR_MPSAFE, true);
222
223	sc->sc_ihs[0] = pci_intr_establish_xname(pc, sc->sc_ihp[0],
224	    IPL_NET, virtio_intr, sc, device_xname(sc->sc_dev));
225	if (sc->sc_ihs[0] == NULL) {
226		aprint_error_dev(self, "couldn't establish INTx\n");
227		return -1;
228	}
229
230	intrstr = pci_intr_string(pc, sc->sc_ihp[0], intrbuf, sizeof(intrbuf));
231	aprint_normal_dev(self, "interrupting at %s\n", intrstr);
232
233	return 0;
234}
235
236static int
237virtio_setup_interrupts(struct virtio_softc *sc)
238{
239	device_t self = sc->sc_dev;
240	pci_chipset_tag_t pc = sc->sc_pa.pa_pc;
241	int error;
242	int nmsix;
243	int counts[PCI_INTR_TYPE_SIZE];
244	pci_intr_type_t max_type;
245
246	nmsix = pci_msix_count(sc->sc_pa.pa_pc, sc->sc_pa.pa_tag);
247	aprint_debug_dev(self, "pci_msix_count=%d\n", nmsix);
248
249	/* We need at least two: one for config and the other for queues */
250	if ((sc->sc_flags & VIRTIO_F_PCI_INTR_MSIX) == 0 || nmsix < 2) {
251		/* Try INTx only */
252		max_type = PCI_INTR_TYPE_INTX;
253		counts[PCI_INTR_TYPE_INTX] = 1;
254	} else {
255		/* Try MSI-X first and INTx second */
256		max_type = PCI_INTR_TYPE_MSIX;
257		counts[PCI_INTR_TYPE_MSIX] = 2;
258		counts[PCI_INTR_TYPE_MSI] = 0;
259		counts[PCI_INTR_TYPE_INTX] = 1;
260	}
261
262 retry:
263	error = pci_intr_alloc(&sc->sc_pa, &sc->sc_ihp, counts, max_type);
264	if (error != 0) {
265		aprint_error_dev(self, "couldn't map interrupt\n");
266		return -1;
267	}
268
269	if (pci_intr_type(pc, sc->sc_ihp[0]) == PCI_INTR_TYPE_MSIX) {
270		sc->sc_ihs = kmem_alloc(sizeof(*sc->sc_ihs) * 2,
271		    KM_SLEEP);
272		if (sc->sc_ihs == NULL) {
273			pci_intr_release(pc, sc->sc_ihp, 2);
274
275			/* Retry INTx */
276			max_type = PCI_INTR_TYPE_INTX;
277			counts[PCI_INTR_TYPE_INTX] = 1;
278			goto retry;
279		}
280
281		error = virtio_setup_msix_interrupts(sc, &sc->sc_pa);
282		if (error != 0) {
283			kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * 2);
284			pci_intr_release(pc, sc->sc_ihp, 2);
285
286			/* Retry INTx */
287			max_type = PCI_INTR_TYPE_INTX;
288			counts[PCI_INTR_TYPE_INTX] = 1;
289			goto retry;
290		}
291
292		sc->sc_ihs_num = 2;
293		sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_MSI;
294	} else if (pci_intr_type(pc, sc->sc_ihp[0]) == PCI_INTR_TYPE_INTX) {
295		sc->sc_ihs = kmem_alloc(sizeof(*sc->sc_ihs) * 1,
296		    KM_SLEEP);
297		if (sc->sc_ihs == NULL) {
298			pci_intr_release(pc, sc->sc_ihp, 1);
299			return -1;
300		}
301
302		error = virtio_setup_intx_interrupt(sc, &sc->sc_pa);
303		if (error != 0) {
304			kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * 1);
305			pci_intr_release(pc, sc->sc_ihp, 1);
306			return -1;
307		}
308
309		sc->sc_ihs_num = 1;
310		sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI;
311	}
312
313	return 0;
314}
315
316static void
317virtio_attach(device_t parent, device_t self, void *aux)
318{
319	struct virtio_softc *sc = device_private(self);
320	struct pci_attach_args *pa = (struct pci_attach_args *)aux;
321	pci_chipset_tag_t pc = pa->pa_pc;
322	pcitag_t tag = pa->pa_tag;
323	int revision;
324	pcireg_t id;
325
326	revision = PCI_REVISION(pa->pa_class);
327	if (revision != 0) {
328		aprint_normal(": unknown revision 0x%02x; giving up\n",
329			      revision);
330		return;
331	}
332	aprint_normal("\n");
333	aprint_naive("\n");
334
335	/* subsystem ID shows what I am */
336	id = pci_conf_read(pc, tag, PCI_SUBSYS_ID_REG);
337	aprint_normal_dev(self, "Virtio %s Device (rev. 0x%02x)\n",
338			  (PCI_SUBSYS_ID(id) < NDEVNAMES?
339			   virtio_device_name[PCI_SUBSYS_ID(id)] : "Unknown"),
340			  revision);
341
342	sc->sc_dev = self;
343	sc->sc_pc = pc;
344	sc->sc_tag = tag;
345	sc->sc_iot = pa->pa_iot;
346	if (pci_dma64_available(pa))
347		sc->sc_dmat = pa->pa_dmat64;
348	else
349		sc->sc_dmat = pa->pa_dmat;
350	sc->sc_config_offset = VIRTIO_CONFIG_DEVICE_CONFIG_NOMSI;
351
352	if (pci_mapreg_map(pa, PCI_MAPREG_START, PCI_MAPREG_TYPE_IO, 0,
353			   &sc->sc_iot, &sc->sc_ioh, NULL, &sc->sc_iosize)) {
354		aprint_error_dev(self, "can't map i/o space\n");
355		return;
356	}
357
358	virtio_device_reset(sc);
359	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_ACK);
360	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_DRIVER);
361
362	/* XXX: use softc as aux... */
363	sc->sc_childdevid = PCI_SUBSYS_ID(id);
364	sc->sc_child = NULL;
365	sc->sc_pa = *pa;
366	virtio_rescan(self, "virtio", 0);
367	return;
368}
369
370/* ARGSUSED */
371static int
372virtio_rescan(device_t self, const char *attr, const int *scan_flags)
373{
374	struct virtio_softc *sc;
375	int r;
376
377	sc = device_private(self);
378	if (sc->sc_child)	/* Child already attached? */
379		return 0;
380	config_found_ia(self, attr, sc, NULL);
381	if (sc->sc_child == NULL) {
382		aprint_error_dev(self,
383				 "no matching child driver; not configured\n");
384		return 0;
385	}
386	if (sc->sc_child == (void*)1) { /* this shows error */
387		aprint_error_dev(self,
388				 "virtio configuration failed\n");
389		virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_FAILED);
390		return 0;
391	}
392
393	r = virtio_setup_interrupts(sc);
394	if (r != 0) {
395		aprint_error_dev(self, "failed to setup interrupts\n");
396		virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_FAILED);
397		return 0;
398	}
399
400	sc->sc_soft_ih = NULL;
401	if (sc->sc_flags & VIRTIO_F_PCI_INTR_SOFTINT) {
402		u_int flags = SOFTINT_NET;
403		if (sc->sc_flags & VIRTIO_F_PCI_INTR_MPSAFE)
404			flags |= SOFTINT_MPSAFE;
405
406		sc->sc_soft_ih = softint_establish(flags, virtio_soft_intr, sc);
407		if (sc->sc_soft_ih == NULL)
408			aprint_error(": failed to establish soft interrupt\n");
409	}
410
411	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK);
412
413	return 0;
414}
415
416static int
417virtio_detach(device_t self, int flags)
418{
419	struct virtio_softc *sc = device_private(self);
420	int r;
421	int i;
422
423	if (sc->sc_child != 0 && sc->sc_child != (void*)1) {
424		r = config_detach(sc->sc_child, flags);
425		if (r)
426			return r;
427	}
428	KASSERT(sc->sc_child == 0 || sc->sc_child == (void*)1);
429	KASSERT(sc->sc_vqs == 0);
430	for (i = 0; i < sc->sc_ihs_num; i++) {
431		if (sc->sc_ihs[i] == NULL)
432			continue;
433		pci_intr_disestablish(sc->sc_pc, sc->sc_ihs[i]);
434	}
435	pci_intr_release(sc->sc_pc, sc->sc_ihp, sc->sc_ihs_num);
436	if (sc->sc_ihs != NULL)
437		kmem_free(sc->sc_ihs, sizeof(*sc->sc_ihs) * sc->sc_ihs_num);
438	sc->sc_ihs_num = 0;
439	if (sc->sc_iosize)
440		bus_space_unmap(sc->sc_iot, sc->sc_ioh, sc->sc_iosize);
441	sc->sc_iosize = 0;
442
443	return 0;
444}
445
446/*
447 * Reset the device.
448 */
449/*
450 * To reset the device to a known state, do following:
451 *	virtio_reset(sc);	     // this will stop the device activity
452 *	<dequeue finished requests>; // virtio_dequeue() still can be called
453 *	<revoke pending requests in the vqs if any>;
454 *	virtio_reinit_begin(sc);     // dequeue prohibitted
455 *	newfeatures = virtio_negotiate_features(sc, requestedfeatures);
456 *	<some other initialization>;
457 *	virtio_reinit_end(sc);	     // device activated; enqueue allowed
458 * Once attached, feature negotiation can only be allowed after virtio_reset.
459 */
460void
461virtio_reset(struct virtio_softc *sc)
462{
463	virtio_device_reset(sc);
464}
465
466void
467virtio_reinit_start(struct virtio_softc *sc)
468{
469	int i;
470
471	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_ACK);
472	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_DRIVER);
473	for (i = 0; i < sc->sc_nvqs; i++) {
474		int n;
475		struct virtqueue *vq = &sc->sc_vqs[i];
476		bus_space_write_2(sc->sc_iot, sc->sc_ioh,
477				  VIRTIO_CONFIG_QUEUE_SELECT,
478				  vq->vq_index);
479		n = bus_space_read_2(sc->sc_iot, sc->sc_ioh,
480				     VIRTIO_CONFIG_QUEUE_SIZE);
481		if (n == 0)	/* vq disappeared */
482			continue;
483		if (n != vq->vq_num) {
484			panic("%s: virtqueue size changed, vq index %d\n",
485			      device_xname(sc->sc_dev),
486			      vq->vq_index);
487		}
488		virtio_init_vq(sc, vq, true);
489		bus_space_write_4(sc->sc_iot, sc->sc_ioh,
490				  VIRTIO_CONFIG_QUEUE_ADDRESS,
491				  (vq->vq_dmamap->dm_segs[0].ds_addr
492				   / VIRTIO_PAGE_SIZE));
493	}
494
495	/* MSI-X should have more than one handles where INTx has just one */
496	if (sc->sc_ihs_num > 1) {
497		if (virtio_setup_msix_vectors(sc) != 0) {
498			aprint_error_dev(sc->sc_dev,
499			    "couldn't setup MSI-X vectors\n");
500			return;
501		}
502	}
503}
504
505void
506virtio_reinit_end(struct virtio_softc *sc)
507{
508	virtio_set_status(sc, VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK);
509}
510
511/*
512 * Feature negotiation.
513 */
514uint32_t
515virtio_negotiate_features(struct virtio_softc *sc, uint32_t guest_features)
516{
517	uint32_t r;
518
519	if (!(device_cfdata(sc->sc_dev)->cf_flags & 1) &&
520	    !(device_cfdata(sc->sc_child)->cf_flags & 1)) /* XXX */
521		guest_features |= VIRTIO_F_RING_INDIRECT_DESC;
522	r = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
523			     VIRTIO_CONFIG_DEVICE_FEATURES);
524	r &= guest_features;
525	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
526			  VIRTIO_CONFIG_GUEST_FEATURES, r);
527	sc->sc_features = r;
528	if (r & VIRTIO_F_RING_INDIRECT_DESC)
529		sc->sc_indirect = true;
530	else
531		sc->sc_indirect = false;
532
533	return r;
534}
535
536/*
537 * Device configuration registers.
538 */
539uint8_t
540virtio_read_device_config_1(struct virtio_softc *sc, int index)
541{
542	return bus_space_read_1(sc->sc_iot, sc->sc_ioh,
543				sc->sc_config_offset + index);
544}
545
546uint16_t
547virtio_read_device_config_2(struct virtio_softc *sc, int index)
548{
549	return bus_space_read_2(sc->sc_iot, sc->sc_ioh,
550				sc->sc_config_offset + index);
551}
552
553uint32_t
554virtio_read_device_config_4(struct virtio_softc *sc, int index)
555{
556	return bus_space_read_4(sc->sc_iot, sc->sc_ioh,
557				sc->sc_config_offset + index);
558}
559
560uint64_t
561virtio_read_device_config_8(struct virtio_softc *sc, int index)
562{
563	uint64_t r;
564
565	r = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
566			     sc->sc_config_offset + index + sizeof(uint32_t));
567	r <<= 32;
568	r += bus_space_read_4(sc->sc_iot, sc->sc_ioh,
569			      sc->sc_config_offset + index);
570	return r;
571}
572
573void
574virtio_write_device_config_1(struct virtio_softc *sc,
575			     int index, uint8_t value)
576{
577	bus_space_write_1(sc->sc_iot, sc->sc_ioh,
578			  sc->sc_config_offset + index, value);
579}
580
581void
582virtio_write_device_config_2(struct virtio_softc *sc,
583			     int index, uint16_t value)
584{
585	bus_space_write_2(sc->sc_iot, sc->sc_ioh,
586			  sc->sc_config_offset + index, value);
587}
588
589void
590virtio_write_device_config_4(struct virtio_softc *sc,
591			     int index, uint32_t value)
592{
593	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
594			  sc->sc_config_offset + index, value);
595}
596
597void
598virtio_write_device_config_8(struct virtio_softc *sc,
599			     int index, uint64_t value)
600{
601	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
602			  sc->sc_config_offset + index,
603			  value & 0xffffffff);
604	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
605			  sc->sc_config_offset + index + sizeof(uint32_t),
606			  value >> 32);
607}
608
609/*
610 * Interrupt handler.
611 */
612static int
613virtio_intr(void *arg)
614{
615	struct virtio_softc *sc = arg;
616	int isr, r = 0;
617
618	/* check and ack the interrupt */
619	isr = bus_space_read_1(sc->sc_iot, sc->sc_ioh,
620			       VIRTIO_CONFIG_ISR_STATUS);
621	if (isr == 0)
622		return 0;
623	if ((isr & VIRTIO_CONFIG_ISR_CONFIG_CHANGE) &&
624	    (sc->sc_config_change != NULL))
625		r = (sc->sc_config_change)(sc);
626	if (sc->sc_intrhand != NULL) {
627		if (sc->sc_soft_ih != NULL)
628			softint_schedule(sc->sc_soft_ih);
629		else
630			r |= (sc->sc_intrhand)(sc);
631	}
632
633	return r;
634}
635
636static int
637virtio_msix_queue_intr(void *arg)
638{
639	struct virtio_softc *sc = arg;
640	int r = 0;
641
642	if (sc->sc_intrhand != NULL) {
643		if (sc->sc_soft_ih != NULL)
644			softint_schedule(sc->sc_soft_ih);
645		else
646			r |= (sc->sc_intrhand)(sc);
647	}
648
649	return r;
650}
651
652static int
653virtio_msix_config_intr(void *arg)
654{
655	struct virtio_softc *sc = arg;
656
657	/* TODO: handle events */
658	aprint_debug_dev(sc->sc_dev, "%s\n", __func__);
659	return 1;
660}
661
662static void
663virtio_soft_intr(void *arg)
664{
665	struct virtio_softc *sc = arg;
666
667	KASSERT(sc->sc_intrhand != NULL);
668
669	(sc->sc_intrhand)(sc);
670}
671
672/*
673 * dmamap sync operations for a virtqueue.
674 */
675static inline void
676vq_sync_descs(struct virtio_softc *sc, struct virtqueue *vq, int ops)
677{
678	/* availoffset == sizeof(vring_desc)*vq_num */
679	bus_dmamap_sync(sc->sc_dmat, vq->vq_dmamap, 0, vq->vq_availoffset,
680			ops);
681}
682
683static inline void
684vq_sync_aring(struct virtio_softc *sc, struct virtqueue *vq, int ops)
685{
686	bus_dmamap_sync(sc->sc_dmat, vq->vq_dmamap,
687			vq->vq_availoffset,
688			offsetof(struct vring_avail, ring)
689			 + vq->vq_num * sizeof(uint16_t),
690			ops);
691}
692
693static inline void
694vq_sync_uring(struct virtio_softc *sc, struct virtqueue *vq, int ops)
695{
696	bus_dmamap_sync(sc->sc_dmat, vq->vq_dmamap,
697			vq->vq_usedoffset,
698			offsetof(struct vring_used, ring)
699			 + vq->vq_num * sizeof(struct vring_used_elem),
700			ops);
701}
702
703static inline void
704vq_sync_indirect(struct virtio_softc *sc, struct virtqueue *vq, int slot,
705		     int ops)
706{
707	int offset = vq->vq_indirectoffset
708		      + sizeof(struct vring_desc) * vq->vq_maxnsegs * slot;
709
710	bus_dmamap_sync(sc->sc_dmat, vq->vq_dmamap,
711			offset, sizeof(struct vring_desc) * vq->vq_maxnsegs,
712			ops);
713}
714
715/*
716 * Can be used as sc_intrhand.
717 */
718/*
719 * Scan vq, bus_dmamap_sync for the vqs (not for the payload),
720 * and calls (*vq_done)() if some entries are consumed.
721 */
722int
723virtio_vq_intr(struct virtio_softc *sc)
724{
725	struct virtqueue *vq;
726	int i, r = 0;
727
728	for (i = 0; i < sc->sc_nvqs; i++) {
729		vq = &sc->sc_vqs[i];
730		if (vq->vq_queued) {
731			vq->vq_queued = 0;
732			vq_sync_aring(sc, vq, BUS_DMASYNC_POSTWRITE);
733		}
734		vq_sync_uring(sc, vq, BUS_DMASYNC_POSTREAD);
735		membar_consumer();
736		if (vq->vq_used_idx != vq->vq_used->idx) {
737			if (vq->vq_done)
738				r |= (vq->vq_done)(vq);
739		}
740	}
741
742	return r;
743}
744
745/*
746 * Start/stop vq interrupt.  No guarantee.
747 */
748void
749virtio_stop_vq_intr(struct virtio_softc *sc, struct virtqueue *vq)
750{
751	vq->vq_avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
752	vq_sync_aring(sc, vq, BUS_DMASYNC_PREWRITE);
753	vq->vq_queued++;
754}
755
756void
757virtio_start_vq_intr(struct virtio_softc *sc, struct virtqueue *vq)
758{
759	vq->vq_avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
760	vq_sync_aring(sc, vq, BUS_DMASYNC_PREWRITE);
761	vq->vq_queued++;
762}
763
764/*
765 * Initialize vq structure.
766 */
767static void
768virtio_init_vq(struct virtio_softc *sc, struct virtqueue *vq,
769    const bool reinit)
770{
771	int i, j;
772	int vq_size = vq->vq_num;
773
774	memset(vq->vq_vaddr, 0, vq->vq_bytesize);
775
776	/* build the indirect descriptor chain */
777	if (vq->vq_indirect != NULL) {
778		struct vring_desc *vd;
779
780		for (i = 0; i < vq_size; i++) {
781			vd = vq->vq_indirect;
782			vd += vq->vq_maxnsegs * i;
783			for (j = 0; j < vq->vq_maxnsegs-1; j++)
784				vd[j].next = j + 1;
785		}
786	}
787
788	/* free slot management */
789	SIMPLEQ_INIT(&vq->vq_freelist);
790	for (i = 0; i < vq_size; i++) {
791		SIMPLEQ_INSERT_TAIL(&vq->vq_freelist,
792				    &vq->vq_entries[i], qe_list);
793		vq->vq_entries[i].qe_index = i;
794	}
795	if (!reinit)
796		mutex_init(&vq->vq_freelist_lock, MUTEX_SPIN, sc->sc_ipl);
797
798	/* enqueue/dequeue status */
799	vq->vq_avail_idx = 0;
800	vq->vq_used_idx = 0;
801	vq->vq_queued = 0;
802	if (!reinit) {
803		mutex_init(&vq->vq_aring_lock, MUTEX_SPIN, sc->sc_ipl);
804		mutex_init(&vq->vq_uring_lock, MUTEX_SPIN, sc->sc_ipl);
805	}
806	vq_sync_aring(sc, vq, BUS_DMASYNC_PREWRITE);
807	vq_sync_uring(sc, vq, BUS_DMASYNC_PREREAD);
808	vq->vq_queued++;
809}
810
811/*
812 * Allocate/free a vq.
813 */
814int
815virtio_alloc_vq(struct virtio_softc *sc, struct virtqueue *vq, int index,
816    int maxsegsize, int maxnsegs, const char *name)
817{
818	int vq_size, allocsize1, allocsize2, allocsize3, allocsize = 0;
819	int rsegs, r;
820#define VIRTQUEUE_ALIGN(n)	(((n)+(VIRTIO_PAGE_SIZE-1))&	\
821				 ~(VIRTIO_PAGE_SIZE-1))
822
823	memset(vq, 0, sizeof(*vq));
824
825	bus_space_write_2(sc->sc_iot, sc->sc_ioh,
826			  VIRTIO_CONFIG_QUEUE_SELECT, index);
827	vq_size = bus_space_read_2(sc->sc_iot, sc->sc_ioh,
828				   VIRTIO_CONFIG_QUEUE_SIZE);
829	if (vq_size == 0) {
830		aprint_error_dev(sc->sc_dev,
831				 "virtqueue not exist, index %d for %s\n",
832				 index, name);
833		goto err;
834	}
835	/* allocsize1: descriptor table + avail ring + pad */
836	allocsize1 = VIRTQUEUE_ALIGN(sizeof(struct vring_desc)*vq_size
837				     + sizeof(uint16_t)*(2+vq_size));
838	/* allocsize2: used ring + pad */
839	allocsize2 = VIRTQUEUE_ALIGN(sizeof(uint16_t)*2
840				     + sizeof(struct vring_used_elem)*vq_size);
841	/* allocsize3: indirect table */
842	if (sc->sc_indirect && maxnsegs >= MINSEG_INDIRECT)
843		allocsize3 = sizeof(struct vring_desc) * maxnsegs * vq_size;
844	else
845		allocsize3 = 0;
846	allocsize = allocsize1 + allocsize2 + allocsize3;
847
848	/* alloc and map the memory */
849	r = bus_dmamem_alloc(sc->sc_dmat, allocsize, VIRTIO_PAGE_SIZE, 0,
850			     &vq->vq_segs[0], 1, &rsegs, BUS_DMA_NOWAIT);
851	if (r != 0) {
852		aprint_error_dev(sc->sc_dev,
853				 "virtqueue %d for %s allocation failed, "
854				 "error code %d\n", index, name, r);
855		goto err;
856	}
857	r = bus_dmamem_map(sc->sc_dmat, &vq->vq_segs[0], 1, allocsize,
858			   &vq->vq_vaddr, BUS_DMA_NOWAIT);
859	if (r != 0) {
860		aprint_error_dev(sc->sc_dev,
861				 "virtqueue %d for %s map failed, "
862				 "error code %d\n", index, name, r);
863		goto err;
864	}
865	r = bus_dmamap_create(sc->sc_dmat, allocsize, 1, allocsize, 0,
866			      BUS_DMA_NOWAIT, &vq->vq_dmamap);
867	if (r != 0) {
868		aprint_error_dev(sc->sc_dev,
869				 "virtqueue %d for %s dmamap creation failed, "
870				 "error code %d\n", index, name, r);
871		goto err;
872	}
873	r = bus_dmamap_load(sc->sc_dmat, vq->vq_dmamap,
874			    vq->vq_vaddr, allocsize, NULL, BUS_DMA_NOWAIT);
875	if (r != 0) {
876		aprint_error_dev(sc->sc_dev,
877				 "virtqueue %d for %s dmamap load failed, "
878				 "error code %d\n", index, name, r);
879		goto err;
880	}
881
882	/* set the vq address */
883	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
884			  VIRTIO_CONFIG_QUEUE_ADDRESS,
885			  (vq->vq_dmamap->dm_segs[0].ds_addr
886			   / VIRTIO_PAGE_SIZE));
887
888	/* remember addresses and offsets for later use */
889	vq->vq_owner = sc;
890	vq->vq_num = vq_size;
891	vq->vq_index = index;
892	vq->vq_desc = vq->vq_vaddr;
893	vq->vq_availoffset = sizeof(struct vring_desc)*vq_size;
894	vq->vq_avail = (void*)(((char*)vq->vq_desc) + vq->vq_availoffset);
895	vq->vq_usedoffset = allocsize1;
896	vq->vq_used = (void*)(((char*)vq->vq_desc) + vq->vq_usedoffset);
897	if (allocsize3 > 0) {
898		vq->vq_indirectoffset = allocsize1 + allocsize2;
899		vq->vq_indirect = (void*)(((char*)vq->vq_desc)
900					  + vq->vq_indirectoffset);
901	}
902	vq->vq_bytesize = allocsize;
903	vq->vq_maxsegsize = maxsegsize;
904	vq->vq_maxnsegs = maxnsegs;
905
906	/* free slot management */
907	vq->vq_entries = kmem_zalloc(sizeof(struct vq_entry)*vq_size,
908				     KM_NOSLEEP);
909	if (vq->vq_entries == NULL) {
910		r = ENOMEM;
911		goto err;
912	}
913
914	virtio_init_vq(sc, vq, false);
915
916	aprint_verbose_dev(sc->sc_dev,
917			   "allocated %u byte for virtqueue %d for %s, "
918			   "size %d\n", allocsize, index, name, vq_size);
919	if (allocsize3 > 0)
920		aprint_verbose_dev(sc->sc_dev,
921				   "using %d byte (%d entries) "
922				   "indirect descriptors\n",
923				   allocsize3, maxnsegs * vq_size);
924	return 0;
925
926err:
927	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
928			  VIRTIO_CONFIG_QUEUE_ADDRESS, 0);
929	if (vq->vq_dmamap)
930		bus_dmamap_destroy(sc->sc_dmat, vq->vq_dmamap);
931	if (vq->vq_vaddr)
932		bus_dmamem_unmap(sc->sc_dmat, vq->vq_vaddr, allocsize);
933	if (vq->vq_segs[0].ds_addr)
934		bus_dmamem_free(sc->sc_dmat, &vq->vq_segs[0], 1);
935	memset(vq, 0, sizeof(*vq));
936
937	return -1;
938}
939
940int
941virtio_free_vq(struct virtio_softc *sc, struct virtqueue *vq)
942{
943	struct vq_entry *qe;
944	int i = 0;
945
946	/* device must be already deactivated */
947	/* confirm the vq is empty */
948	SIMPLEQ_FOREACH(qe, &vq->vq_freelist, qe_list) {
949		i++;
950	}
951	if (i != vq->vq_num) {
952		printf("%s: freeing non-empty vq, index %d\n",
953		       device_xname(sc->sc_dev), vq->vq_index);
954		return EBUSY;
955	}
956
957	/* tell device that there's no virtqueue any longer */
958	bus_space_write_2(sc->sc_iot, sc->sc_ioh,
959			  VIRTIO_CONFIG_QUEUE_SELECT, vq->vq_index);
960	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
961			  VIRTIO_CONFIG_QUEUE_ADDRESS, 0);
962
963	kmem_free(vq->vq_entries, sizeof(*vq->vq_entries) * vq->vq_num);
964	bus_dmamap_unload(sc->sc_dmat, vq->vq_dmamap);
965	bus_dmamap_destroy(sc->sc_dmat, vq->vq_dmamap);
966	bus_dmamem_unmap(sc->sc_dmat, vq->vq_vaddr, vq->vq_bytesize);
967	bus_dmamem_free(sc->sc_dmat, &vq->vq_segs[0], 1);
968	mutex_destroy(&vq->vq_freelist_lock);
969	mutex_destroy(&vq->vq_uring_lock);
970	mutex_destroy(&vq->vq_aring_lock);
971	memset(vq, 0, sizeof(*vq));
972
973	return 0;
974}
975
976/*
977 * Free descriptor management.
978 */
979static struct vq_entry *
980vq_alloc_entry(struct virtqueue *vq)
981{
982	struct vq_entry *qe;
983
984	mutex_enter(&vq->vq_freelist_lock);
985	if (SIMPLEQ_EMPTY(&vq->vq_freelist)) {
986		mutex_exit(&vq->vq_freelist_lock);
987		return NULL;
988	}
989	qe = SIMPLEQ_FIRST(&vq->vq_freelist);
990	SIMPLEQ_REMOVE_HEAD(&vq->vq_freelist, qe_list);
991	mutex_exit(&vq->vq_freelist_lock);
992
993	return qe;
994}
995
996static void
997vq_free_entry(struct virtqueue *vq, struct vq_entry *qe)
998{
999	mutex_enter(&vq->vq_freelist_lock);
1000	SIMPLEQ_INSERT_TAIL(&vq->vq_freelist, qe, qe_list);
1001	mutex_exit(&vq->vq_freelist_lock);
1002
1003	return;
1004}
1005
1006/*
1007 * Enqueue several dmamaps as a single request.
1008 */
1009/*
1010 * Typical usage:
1011 *  <queue size> number of followings are stored in arrays
1012 *  - command blocks (in dmamem) should be pre-allocated and mapped
1013 *  - dmamaps for command blocks should be pre-allocated and loaded
1014 *  - dmamaps for payload should be pre-allocated
1015 *      r = virtio_enqueue_prep(sc, vq, &slot);		// allocate a slot
1016 *	if (r)		// currently 0 or EAGAIN
1017 *	  return r;
1018 *	r = bus_dmamap_load(dmat, dmamap_payload[slot], data, count, ..);
1019 *	if (r) {
1020 *	  virtio_enqueue_abort(sc, vq, slot);
1021 *	  return r;
1022 *	}
1023 *	r = virtio_enqueue_reserve(sc, vq, slot,
1024 *				   dmamap_payload[slot]->dm_nsegs+1);
1025 *							// ^ +1 for command
1026 *	if (r) {	// currently 0 or EAGAIN
1027 *	  bus_dmamap_unload(dmat, dmamap_payload[slot]);
1028 *	  return r;					// do not call abort()
1029 *	}
1030 *	<setup and prepare commands>
1031 *	bus_dmamap_sync(dmat, dmamap_cmd[slot],... BUS_DMASYNC_PREWRITE);
1032 *	bus_dmamap_sync(dmat, dmamap_payload[slot],...);
1033 *	virtio_enqueue(sc, vq, slot, dmamap_cmd[slot], false);
1034 *	virtio_enqueue(sc, vq, slot, dmamap_payload[slot], iswrite);
1035 *	virtio_enqueue_commit(sc, vq, slot, true);
1036 */
1037
1038/*
1039 * enqueue_prep: allocate a slot number
1040 */
1041int
1042virtio_enqueue_prep(struct virtio_softc *sc, struct virtqueue *vq, int *slotp)
1043{
1044	struct vq_entry *qe1;
1045
1046	KASSERT(slotp != NULL);
1047
1048	qe1 = vq_alloc_entry(vq);
1049	if (qe1 == NULL)
1050		return EAGAIN;
1051	/* next slot is not allocated yet */
1052	qe1->qe_next = -1;
1053	*slotp = qe1->qe_index;
1054
1055	return 0;
1056}
1057
1058/*
1059 * enqueue_reserve: allocate remaining slots and build the descriptor chain.
1060 */
1061int
1062virtio_enqueue_reserve(struct virtio_softc *sc, struct virtqueue *vq,
1063		       int slot, int nsegs)
1064{
1065	int indirect;
1066	struct vq_entry *qe1 = &vq->vq_entries[slot];
1067
1068	KASSERT(qe1->qe_next == -1);
1069	KASSERT(1 <= nsegs && nsegs <= vq->vq_num);
1070
1071	if ((vq->vq_indirect != NULL) &&
1072	    (nsegs >= MINSEG_INDIRECT) &&
1073	    (nsegs <= vq->vq_maxnsegs))
1074		indirect = 1;
1075	else
1076		indirect = 0;
1077	qe1->qe_indirect = indirect;
1078
1079	if (indirect) {
1080		struct vring_desc *vd;
1081		int i;
1082
1083		vd = &vq->vq_desc[qe1->qe_index];
1084		vd->addr = vq->vq_dmamap->dm_segs[0].ds_addr
1085			+ vq->vq_indirectoffset;
1086		vd->addr += sizeof(struct vring_desc)
1087			* vq->vq_maxnsegs * qe1->qe_index;
1088		vd->len = sizeof(struct vring_desc) * nsegs;
1089		vd->flags = VRING_DESC_F_INDIRECT;
1090
1091		vd = vq->vq_indirect;
1092		vd += vq->vq_maxnsegs * qe1->qe_index;
1093		qe1->qe_desc_base = vd;
1094
1095		for (i = 0; i < nsegs-1; i++) {
1096			vd[i].flags = VRING_DESC_F_NEXT;
1097		}
1098		vd[i].flags = 0;
1099		qe1->qe_next = 0;
1100
1101		return 0;
1102	} else {
1103		struct vring_desc *vd;
1104		struct vq_entry *qe;
1105		int i, s;
1106
1107		vd = &vq->vq_desc[0];
1108		qe1->qe_desc_base = vd;
1109		qe1->qe_next = qe1->qe_index;
1110		s = slot;
1111		for (i = 0; i < nsegs - 1; i++) {
1112			qe = vq_alloc_entry(vq);
1113			if (qe == NULL) {
1114				vd[s].flags = 0;
1115				virtio_enqueue_abort(sc, vq, slot);
1116				return EAGAIN;
1117			}
1118			vd[s].flags = VRING_DESC_F_NEXT;
1119			vd[s].next = qe->qe_index;
1120			s = qe->qe_index;
1121		}
1122		vd[s].flags = 0;
1123
1124		return 0;
1125	}
1126}
1127
1128/*
1129 * enqueue: enqueue a single dmamap.
1130 */
1131int
1132virtio_enqueue(struct virtio_softc *sc, struct virtqueue *vq, int slot,
1133	       bus_dmamap_t dmamap, bool write)
1134{
1135	struct vq_entry *qe1 = &vq->vq_entries[slot];
1136	struct vring_desc *vd = qe1->qe_desc_base;
1137	int i;
1138	int s = qe1->qe_next;
1139
1140	KASSERT(s >= 0);
1141	KASSERT(dmamap->dm_nsegs > 0);
1142
1143	for (i = 0; i < dmamap->dm_nsegs; i++) {
1144		vd[s].addr = dmamap->dm_segs[i].ds_addr;
1145		vd[s].len = dmamap->dm_segs[i].ds_len;
1146		if (!write)
1147			vd[s].flags |= VRING_DESC_F_WRITE;
1148		s = vd[s].next;
1149	}
1150	qe1->qe_next = s;
1151
1152	return 0;
1153}
1154
1155int
1156virtio_enqueue_p(struct virtio_softc *sc, struct virtqueue *vq, int slot,
1157		 bus_dmamap_t dmamap, bus_addr_t start, bus_size_t len,
1158		 bool write)
1159{
1160	struct vq_entry *qe1 = &vq->vq_entries[slot];
1161	struct vring_desc *vd = qe1->qe_desc_base;
1162	int s = qe1->qe_next;
1163
1164	KASSERT(s >= 0);
1165	KASSERT(dmamap->dm_nsegs == 1); /* XXX */
1166	KASSERT((dmamap->dm_segs[0].ds_len > start) &&
1167		(dmamap->dm_segs[0].ds_len >= start + len));
1168
1169	vd[s].addr = dmamap->dm_segs[0].ds_addr + start;
1170	vd[s].len = len;
1171	if (!write)
1172		vd[s].flags |= VRING_DESC_F_WRITE;
1173	qe1->qe_next = vd[s].next;
1174
1175	return 0;
1176}
1177
1178/*
1179 * enqueue_commit: add it to the aring.
1180 */
1181int
1182virtio_enqueue_commit(struct virtio_softc *sc, struct virtqueue *vq, int slot,
1183		      bool notifynow)
1184{
1185	struct vq_entry *qe1;
1186
1187	if (slot < 0) {
1188		mutex_enter(&vq->vq_aring_lock);
1189		goto notify;
1190	}
1191	vq_sync_descs(sc, vq, BUS_DMASYNC_PREWRITE);
1192	qe1 = &vq->vq_entries[slot];
1193	if (qe1->qe_indirect)
1194		vq_sync_indirect(sc, vq, slot, BUS_DMASYNC_PREWRITE);
1195	mutex_enter(&vq->vq_aring_lock);
1196	vq->vq_avail->ring[(vq->vq_avail_idx++) % vq->vq_num] = slot;
1197
1198notify:
1199	if (notifynow) {
1200		vq_sync_aring(sc, vq, BUS_DMASYNC_PREWRITE);
1201		vq_sync_uring(sc, vq, BUS_DMASYNC_PREREAD);
1202		membar_producer();
1203		vq->vq_avail->idx = vq->vq_avail_idx;
1204		vq_sync_aring(sc, vq, BUS_DMASYNC_PREWRITE);
1205		membar_producer();
1206		vq->vq_queued++;
1207		vq_sync_uring(sc, vq, BUS_DMASYNC_POSTREAD);
1208		membar_consumer();
1209		if (!(vq->vq_used->flags & VRING_USED_F_NO_NOTIFY))
1210			bus_space_write_2(sc->sc_iot, sc->sc_ioh,
1211					  VIRTIO_CONFIG_QUEUE_NOTIFY,
1212					  vq->vq_index);
1213	}
1214	mutex_exit(&vq->vq_aring_lock);
1215
1216	return 0;
1217}
1218
1219/*
1220 * enqueue_abort: rollback.
1221 */
1222int
1223virtio_enqueue_abort(struct virtio_softc *sc, struct virtqueue *vq, int slot)
1224{
1225	struct vq_entry *qe = &vq->vq_entries[slot];
1226	struct vring_desc *vd;
1227	int s;
1228
1229	if (qe->qe_next < 0) {
1230		vq_free_entry(vq, qe);
1231		return 0;
1232	}
1233
1234	s = slot;
1235	vd = &vq->vq_desc[0];
1236	while (vd[s].flags & VRING_DESC_F_NEXT) {
1237		s = vd[s].next;
1238		vq_free_entry(vq, qe);
1239		qe = &vq->vq_entries[s];
1240	}
1241	vq_free_entry(vq, qe);
1242	return 0;
1243}
1244
1245/*
1246 * Dequeue a request.
1247 */
1248/*
1249 * dequeue: dequeue a request from uring; dmamap_sync for uring is
1250 *	    already done in the interrupt handler.
1251 */
1252int
1253virtio_dequeue(struct virtio_softc *sc, struct virtqueue *vq,
1254	       int *slotp, int *lenp)
1255{
1256	uint16_t slot, usedidx;
1257	struct vq_entry *qe;
1258
1259	if (vq->vq_used_idx == vq->vq_used->idx)
1260		return ENOENT;
1261	mutex_enter(&vq->vq_uring_lock);
1262	usedidx = vq->vq_used_idx++;
1263	mutex_exit(&vq->vq_uring_lock);
1264	usedidx %= vq->vq_num;
1265	slot = vq->vq_used->ring[usedidx].id;
1266	qe = &vq->vq_entries[slot];
1267
1268	if (qe->qe_indirect)
1269		vq_sync_indirect(sc, vq, slot, BUS_DMASYNC_POSTWRITE);
1270
1271	if (slotp)
1272		*slotp = slot;
1273	if (lenp)
1274		*lenp = vq->vq_used->ring[usedidx].len;
1275
1276	return 0;
1277}
1278
1279/*
1280 * dequeue_commit: complete dequeue; the slot is recycled for future use.
1281 *                 if you forget to call this the slot will be leaked.
1282 */
1283int
1284virtio_dequeue_commit(struct virtio_softc *sc, struct virtqueue *vq, int slot)
1285{
1286	struct vq_entry *qe = &vq->vq_entries[slot];
1287	struct vring_desc *vd = &vq->vq_desc[0];
1288	int s = slot;
1289
1290	while (vd[s].flags & VRING_DESC_F_NEXT) {
1291		s = vd[s].next;
1292		vq_free_entry(vq, qe);
1293		qe = &vq->vq_entries[s];
1294	}
1295	vq_free_entry(vq, qe);
1296
1297	return 0;
1298}
1299
1300MODULE(MODULE_CLASS_DRIVER, virtio, "pci");
1301
1302#ifdef _MODULE
1303#include "ioconf.c"
1304#endif
1305
1306static int
1307virtio_modcmd(modcmd_t cmd, void *opaque)
1308{
1309	int error = 0;
1310
1311#ifdef _MODULE
1312	switch (cmd) {
1313	case MODULE_CMD_INIT:
1314		error = config_init_component(cfdriver_ioconf_virtio,
1315		    cfattach_ioconf_virtio, cfdata_ioconf_virtio);
1316		break;
1317	case MODULE_CMD_FINI:
1318		error = config_fini_component(cfdriver_ioconf_virtio,
1319		    cfattach_ioconf_virtio, cfdata_ioconf_virtio);
1320		break;
1321	default:
1322		error = ENOTTY;
1323		break;
1324	}
1325#endif
1326
1327	return error;
1328}
1329