xref: /netbsd-src/sys/dev/pci/virtio.c (revision e89934bbf778a6d6d6894877c4da59d0c7835b0f)
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 
49 static int	virtio_match(device_t, cfdata_t, void *);
50 static void	virtio_attach(device_t, device_t, void *);
51 static int	virtio_rescan(device_t, const char *, const int *);
52 static int	virtio_detach(device_t, int);
53 static int	virtio_intr(void *arg);
54 static int	virtio_msix_queue_intr(void *);
55 static int	virtio_msix_config_intr(void *);
56 static int	virtio_setup_msix_vectors(struct virtio_softc *);
57 static int	virtio_setup_msix_interrupts(struct virtio_softc *,
58 		    struct pci_attach_args *);
59 static int	virtio_setup_intx_interrupt(struct virtio_softc *,
60 		    struct pci_attach_args *);
61 static int	virtio_setup_interrupts(struct virtio_softc *);
62 static void	virtio_soft_intr(void *arg);
63 static void	virtio_init_vq(struct virtio_softc *,
64 		    struct virtqueue *, const bool);
65 
66 CFATTACH_DECL3_NEW(virtio, sizeof(struct virtio_softc),
67     virtio_match, virtio_attach, virtio_detach, NULL, virtio_rescan, NULL,
68     DVF_DETACH_SHUTDOWN);
69 
70 static void
71 virtio_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 
84 static int
85 virtio_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 
103 static 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 
121 static int
122 virtio_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 
154 static int
155 virtio_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 
200 error:
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 
211 static int
212 virtio_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 
236 static int
237 virtio_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 
316 static void
317 virtio_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 */
371 static int
372 virtio_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 
416 static int
417 virtio_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  */
460 void
461 virtio_reset(struct virtio_softc *sc)
462 {
463 	virtio_device_reset(sc);
464 }
465 
466 void
467 virtio_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 
505 void
506 virtio_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  */
514 uint32_t
515 virtio_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  */
539 uint8_t
540 virtio_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 
546 uint16_t
547 virtio_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 
553 uint32_t
554 virtio_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 
560 uint64_t
561 virtio_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 
573 void
574 virtio_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 
581 void
582 virtio_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 
589 void
590 virtio_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 
597 void
598 virtio_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  */
612 static int
613 virtio_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 
636 static int
637 virtio_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 
652 static int
653 virtio_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 
662 static void
663 virtio_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  */
675 static inline void
676 vq_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 
683 static inline void
684 vq_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 
693 static inline void
694 vq_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 
703 static inline void
704 vq_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  */
722 int
723 virtio_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  */
748 void
749 virtio_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 
756 void
757 virtio_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  */
767 static void
768 virtio_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  */
814 int
815 virtio_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 
926 err:
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 
940 int
941 virtio_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  */
979 static struct vq_entry *
980 vq_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 
996 static void
997 vq_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  */
1041 int
1042 virtio_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  */
1061 int
1062 virtio_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  */
1131 int
1132 virtio_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 
1155 int
1156 virtio_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  */
1181 int
1182 virtio_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 
1198 notify:
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  */
1222 int
1223 virtio_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  */
1252 int
1253 virtio_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  */
1283 int
1284 virtio_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 
1300 MODULE(MODULE_CLASS_DRIVER, virtio, "pci");
1301 
1302 #ifdef _MODULE
1303 #include "ioconf.c"
1304 #endif
1305 
1306 static int
1307 virtio_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