xref: /freebsd/sys/dev/ioat/ioat.c (revision e60680024afe8ec84ded577e77965e9a44595f2b)
1 /*-
2  * Copyright (C) 2012 Intel Corporation
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/conf.h>
34 #include <sys/ioccom.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/module.h>
39 #include <sys/mutex.h>
40 #include <sys/rman.h>
41 #include <sys/sbuf.h>
42 #include <sys/sysctl.h>
43 #include <sys/time.h>
44 #include <dev/pci/pcireg.h>
45 #include <dev/pci/pcivar.h>
46 #include <machine/bus.h>
47 #include <machine/resource.h>
48 #include <machine/stdarg.h>
49 
50 #include "ioat.h"
51 #include "ioat_hw.h"
52 #include "ioat_internal.h"
53 
54 #define	IOAT_INTR_TIMO	(hz / 10)
55 #define	IOAT_REFLK	(&ioat->submit_lock)
56 
57 static int ioat_probe(device_t device);
58 static int ioat_attach(device_t device);
59 static int ioat_detach(device_t device);
60 static int ioat_setup_intr(struct ioat_softc *ioat);
61 static int ioat_teardown_intr(struct ioat_softc *ioat);
62 static int ioat3_attach(device_t device);
63 static int ioat_start_channel(struct ioat_softc *ioat);
64 static int ioat_map_pci_bar(struct ioat_softc *ioat);
65 static void ioat_dmamap_cb(void *arg, bus_dma_segment_t *segs, int nseg,
66     int error);
67 static void ioat_interrupt_handler(void *arg);
68 static boolean_t ioat_model_resets_msix(struct ioat_softc *ioat);
69 static int chanerr_to_errno(uint32_t);
70 static void ioat_process_events(struct ioat_softc *ioat);
71 static inline uint32_t ioat_get_active(struct ioat_softc *ioat);
72 static inline uint32_t ioat_get_ring_space(struct ioat_softc *ioat);
73 static void ioat_free_ring(struct ioat_softc *, uint32_t size,
74     struct ioat_descriptor **);
75 static void ioat_free_ring_entry(struct ioat_softc *ioat,
76     struct ioat_descriptor *desc);
77 static struct ioat_descriptor *ioat_alloc_ring_entry(struct ioat_softc *,
78     int mflags);
79 static int ioat_reserve_space(struct ioat_softc *, uint32_t, int mflags);
80 static struct ioat_descriptor *ioat_get_ring_entry(struct ioat_softc *ioat,
81     uint32_t index);
82 static struct ioat_descriptor **ioat_prealloc_ring(struct ioat_softc *,
83     uint32_t size, boolean_t need_dscr, int mflags);
84 static int ring_grow(struct ioat_softc *, uint32_t oldorder,
85     struct ioat_descriptor **);
86 static int ring_shrink(struct ioat_softc *, uint32_t oldorder,
87     struct ioat_descriptor **);
88 static void ioat_halted_debug(struct ioat_softc *, uint32_t);
89 static void ioat_timer_callback(void *arg);
90 static void dump_descriptor(void *hw_desc);
91 static void ioat_submit_single(struct ioat_softc *ioat);
92 static void ioat_comp_update_map(void *arg, bus_dma_segment_t *seg, int nseg,
93     int error);
94 static int ioat_reset_hw(struct ioat_softc *ioat);
95 static void ioat_setup_sysctl(device_t device);
96 static int sysctl_handle_reset(SYSCTL_HANDLER_ARGS);
97 static inline struct ioat_softc *ioat_get(struct ioat_softc *,
98     enum ioat_ref_kind);
99 static inline void ioat_put(struct ioat_softc *, enum ioat_ref_kind);
100 static inline void _ioat_putn(struct ioat_softc *, uint32_t,
101     enum ioat_ref_kind, boolean_t);
102 static inline void ioat_putn(struct ioat_softc *, uint32_t,
103     enum ioat_ref_kind);
104 static inline void ioat_putn_locked(struct ioat_softc *, uint32_t,
105     enum ioat_ref_kind);
106 static void ioat_drain_locked(struct ioat_softc *);
107 
108 #define	ioat_log_message(v, ...) do {					\
109 	if ((v) <= g_ioat_debug_level) {				\
110 		device_printf(ioat->device, __VA_ARGS__);		\
111 	}								\
112 } while (0)
113 
114 MALLOC_DEFINE(M_IOAT, "ioat", "ioat driver memory allocations");
115 SYSCTL_NODE(_hw, OID_AUTO, ioat, CTLFLAG_RD, 0, "ioat node");
116 
117 static int g_force_legacy_interrupts;
118 SYSCTL_INT(_hw_ioat, OID_AUTO, force_legacy_interrupts, CTLFLAG_RDTUN,
119     &g_force_legacy_interrupts, 0, "Set to non-zero to force MSI-X disabled");
120 
121 int g_ioat_debug_level = 0;
122 SYSCTL_INT(_hw_ioat, OID_AUTO, debug_level, CTLFLAG_RWTUN, &g_ioat_debug_level,
123     0, "Set log level (0-3) for ioat(4). Higher is more verbose.");
124 
125 /*
126  * OS <-> Driver interface structures
127  */
128 static device_method_t ioat_pci_methods[] = {
129 	/* Device interface */
130 	DEVMETHOD(device_probe,     ioat_probe),
131 	DEVMETHOD(device_attach,    ioat_attach),
132 	DEVMETHOD(device_detach,    ioat_detach),
133 	{ 0, 0 }
134 };
135 
136 static driver_t ioat_pci_driver = {
137 	"ioat",
138 	ioat_pci_methods,
139 	sizeof(struct ioat_softc),
140 };
141 
142 static devclass_t ioat_devclass;
143 DRIVER_MODULE(ioat, pci, ioat_pci_driver, ioat_devclass, 0, 0);
144 MODULE_VERSION(ioat, 1);
145 
146 /*
147  * Private data structures
148  */
149 static struct ioat_softc *ioat_channel[IOAT_MAX_CHANNELS];
150 static int ioat_channel_index = 0;
151 SYSCTL_INT(_hw_ioat, OID_AUTO, channels, CTLFLAG_RD, &ioat_channel_index, 0,
152     "Number of IOAT channels attached");
153 
154 static struct _pcsid
155 {
156 	u_int32_t   type;
157 	const char  *desc;
158 } pci_ids[] = {
159 	{ 0x34308086, "TBG IOAT Ch0" },
160 	{ 0x34318086, "TBG IOAT Ch1" },
161 	{ 0x34328086, "TBG IOAT Ch2" },
162 	{ 0x34338086, "TBG IOAT Ch3" },
163 	{ 0x34298086, "TBG IOAT Ch4" },
164 	{ 0x342a8086, "TBG IOAT Ch5" },
165 	{ 0x342b8086, "TBG IOAT Ch6" },
166 	{ 0x342c8086, "TBG IOAT Ch7" },
167 
168 	{ 0x37108086, "JSF IOAT Ch0" },
169 	{ 0x37118086, "JSF IOAT Ch1" },
170 	{ 0x37128086, "JSF IOAT Ch2" },
171 	{ 0x37138086, "JSF IOAT Ch3" },
172 	{ 0x37148086, "JSF IOAT Ch4" },
173 	{ 0x37158086, "JSF IOAT Ch5" },
174 	{ 0x37168086, "JSF IOAT Ch6" },
175 	{ 0x37178086, "JSF IOAT Ch7" },
176 	{ 0x37188086, "JSF IOAT Ch0 (RAID)" },
177 	{ 0x37198086, "JSF IOAT Ch1 (RAID)" },
178 
179 	{ 0x3c208086, "SNB IOAT Ch0" },
180 	{ 0x3c218086, "SNB IOAT Ch1" },
181 	{ 0x3c228086, "SNB IOAT Ch2" },
182 	{ 0x3c238086, "SNB IOAT Ch3" },
183 	{ 0x3c248086, "SNB IOAT Ch4" },
184 	{ 0x3c258086, "SNB IOAT Ch5" },
185 	{ 0x3c268086, "SNB IOAT Ch6" },
186 	{ 0x3c278086, "SNB IOAT Ch7" },
187 	{ 0x3c2e8086, "SNB IOAT Ch0 (RAID)" },
188 	{ 0x3c2f8086, "SNB IOAT Ch1 (RAID)" },
189 
190 	{ 0x0e208086, "IVB IOAT Ch0" },
191 	{ 0x0e218086, "IVB IOAT Ch1" },
192 	{ 0x0e228086, "IVB IOAT Ch2" },
193 	{ 0x0e238086, "IVB IOAT Ch3" },
194 	{ 0x0e248086, "IVB IOAT Ch4" },
195 	{ 0x0e258086, "IVB IOAT Ch5" },
196 	{ 0x0e268086, "IVB IOAT Ch6" },
197 	{ 0x0e278086, "IVB IOAT Ch7" },
198 	{ 0x0e2e8086, "IVB IOAT Ch0 (RAID)" },
199 	{ 0x0e2f8086, "IVB IOAT Ch1 (RAID)" },
200 
201 	{ 0x2f208086, "HSW IOAT Ch0" },
202 	{ 0x2f218086, "HSW IOAT Ch1" },
203 	{ 0x2f228086, "HSW IOAT Ch2" },
204 	{ 0x2f238086, "HSW IOAT Ch3" },
205 	{ 0x2f248086, "HSW IOAT Ch4" },
206 	{ 0x2f258086, "HSW IOAT Ch5" },
207 	{ 0x2f268086, "HSW IOAT Ch6" },
208 	{ 0x2f278086, "HSW IOAT Ch7" },
209 	{ 0x2f2e8086, "HSW IOAT Ch0 (RAID)" },
210 	{ 0x2f2f8086, "HSW IOAT Ch1 (RAID)" },
211 
212 	{ 0x0c508086, "BWD IOAT Ch0" },
213 	{ 0x0c518086, "BWD IOAT Ch1" },
214 	{ 0x0c528086, "BWD IOAT Ch2" },
215 	{ 0x0c538086, "BWD IOAT Ch3" },
216 
217 	{ 0x6f508086, "BDXDE IOAT Ch0" },
218 	{ 0x6f518086, "BDXDE IOAT Ch1" },
219 	{ 0x6f528086, "BDXDE IOAT Ch2" },
220 	{ 0x6f538086, "BDXDE IOAT Ch3" },
221 
222 	{ 0x6f208086, "BDX IOAT Ch0" },
223 	{ 0x6f218086, "BDX IOAT Ch1" },
224 	{ 0x6f228086, "BDX IOAT Ch2" },
225 	{ 0x6f238086, "BDX IOAT Ch3" },
226 	{ 0x6f248086, "BDX IOAT Ch4" },
227 	{ 0x6f258086, "BDX IOAT Ch5" },
228 	{ 0x6f268086, "BDX IOAT Ch6" },
229 	{ 0x6f278086, "BDX IOAT Ch7" },
230 	{ 0x6f2e8086, "BDX IOAT Ch0 (RAID)" },
231 	{ 0x6f2f8086, "BDX IOAT Ch1 (RAID)" },
232 
233 	{ 0x00000000, NULL           }
234 };
235 
236 /*
237  * OS <-> Driver linkage functions
238  */
239 static int
240 ioat_probe(device_t device)
241 {
242 	struct _pcsid *ep;
243 	u_int32_t type;
244 
245 	type = pci_get_devid(device);
246 	for (ep = pci_ids; ep->type; ep++) {
247 		if (ep->type == type) {
248 			device_set_desc(device, ep->desc);
249 			return (0);
250 		}
251 	}
252 	return (ENXIO);
253 }
254 
255 static int
256 ioat_attach(device_t device)
257 {
258 	struct ioat_softc *ioat;
259 	int error;
260 
261 	ioat = DEVICE2SOFTC(device);
262 	ioat->device = device;
263 
264 	error = ioat_map_pci_bar(ioat);
265 	if (error != 0)
266 		goto err;
267 
268 	ioat->version = ioat_read_cbver(ioat);
269 	if (ioat->version < IOAT_VER_3_0) {
270 		error = ENODEV;
271 		goto err;
272 	}
273 
274 	error = ioat3_attach(device);
275 	if (error != 0)
276 		goto err;
277 
278 	error = pci_enable_busmaster(device);
279 	if (error != 0)
280 		goto err;
281 
282 	error = ioat_setup_intr(ioat);
283 	if (error != 0)
284 		goto err;
285 
286 	error = ioat_reset_hw(ioat);
287 	if (error != 0)
288 		goto err;
289 
290 	ioat_process_events(ioat);
291 	ioat_setup_sysctl(device);
292 
293 	ioat->chan_idx = ioat_channel_index;
294 	ioat_channel[ioat_channel_index++] = ioat;
295 	ioat_test_attach();
296 
297 err:
298 	if (error != 0)
299 		ioat_detach(device);
300 	return (error);
301 }
302 
303 static int
304 ioat_detach(device_t device)
305 {
306 	struct ioat_softc *ioat;
307 
308 	ioat = DEVICE2SOFTC(device);
309 
310 	ioat_test_detach();
311 
312 	mtx_lock(IOAT_REFLK);
313 	ioat->quiescing = TRUE;
314 	ioat_channel[ioat->chan_idx] = NULL;
315 
316 	ioat_drain_locked(ioat);
317 	mtx_unlock(IOAT_REFLK);
318 
319 	ioat_teardown_intr(ioat);
320 	callout_drain(&ioat->timer);
321 
322 	pci_disable_busmaster(device);
323 
324 	if (ioat->pci_resource != NULL)
325 		bus_release_resource(device, SYS_RES_MEMORY,
326 		    ioat->pci_resource_id, ioat->pci_resource);
327 
328 	if (ioat->ring != NULL)
329 		ioat_free_ring(ioat, 1 << ioat->ring_size_order, ioat->ring);
330 
331 	if (ioat->comp_update != NULL) {
332 		bus_dmamap_unload(ioat->comp_update_tag, ioat->comp_update_map);
333 		bus_dmamem_free(ioat->comp_update_tag, ioat->comp_update,
334 		    ioat->comp_update_map);
335 		bus_dma_tag_destroy(ioat->comp_update_tag);
336 	}
337 
338 	bus_dma_tag_destroy(ioat->hw_desc_tag);
339 
340 	return (0);
341 }
342 
343 static int
344 ioat_teardown_intr(struct ioat_softc *ioat)
345 {
346 
347 	if (ioat->tag != NULL)
348 		bus_teardown_intr(ioat->device, ioat->res, ioat->tag);
349 
350 	if (ioat->res != NULL)
351 		bus_release_resource(ioat->device, SYS_RES_IRQ,
352 		    rman_get_rid(ioat->res), ioat->res);
353 
354 	pci_release_msi(ioat->device);
355 	return (0);
356 }
357 
358 static int
359 ioat_start_channel(struct ioat_softc *ioat)
360 {
361 	uint64_t status;
362 	uint32_t chanerr;
363 	int i;
364 
365 	ioat_acquire(&ioat->dmaengine);
366 	ioat_null(&ioat->dmaengine, NULL, NULL, 0);
367 	ioat_release(&ioat->dmaengine);
368 
369 	for (i = 0; i < 100; i++) {
370 		DELAY(1);
371 		status = ioat_get_chansts(ioat);
372 		if (is_ioat_idle(status))
373 			return (0);
374 	}
375 
376 	chanerr = ioat_read_4(ioat, IOAT_CHANERR_OFFSET);
377 	ioat_log_message(0, "could not start channel: "
378 	    "status = %#jx error = %b\n", (uintmax_t)status, (int)chanerr,
379 	    IOAT_CHANERR_STR);
380 	return (ENXIO);
381 }
382 
383 /*
384  * Initialize Hardware
385  */
386 static int
387 ioat3_attach(device_t device)
388 {
389 	struct ioat_softc *ioat;
390 	struct ioat_descriptor **ring;
391 	struct ioat_descriptor *next;
392 	struct ioat_dma_hw_descriptor *dma_hw_desc;
393 	int i, num_descriptors;
394 	int error;
395 	uint8_t xfercap;
396 
397 	error = 0;
398 	ioat = DEVICE2SOFTC(device);
399 	ioat->capabilities = ioat_read_dmacapability(ioat);
400 
401 	ioat_log_message(1, "Capabilities: %b\n", (int)ioat->capabilities,
402 	    IOAT_DMACAP_STR);
403 
404 	xfercap = ioat_read_xfercap(ioat);
405 	ioat->max_xfer_size = 1 << xfercap;
406 
407 	ioat->intrdelay_supported = (ioat_read_2(ioat, IOAT_INTRDELAY_OFFSET) &
408 	    IOAT_INTRDELAY_SUPPORTED) != 0;
409 	if (ioat->intrdelay_supported)
410 		ioat->intrdelay_max = IOAT_INTRDELAY_US_MASK;
411 
412 	/* TODO: need to check DCA here if we ever do XOR/PQ */
413 
414 	mtx_init(&ioat->submit_lock, "ioat_submit", NULL, MTX_DEF);
415 	mtx_init(&ioat->cleanup_lock, "ioat_cleanup", NULL, MTX_DEF);
416 	callout_init(&ioat->timer, 1);
417 
418 	/* Establish lock order for Witness */
419 	mtx_lock(&ioat->submit_lock);
420 	mtx_lock(&ioat->cleanup_lock);
421 	mtx_unlock(&ioat->cleanup_lock);
422 	mtx_unlock(&ioat->submit_lock);
423 
424 	ioat->is_resize_pending = FALSE;
425 	ioat->is_completion_pending = FALSE;
426 	ioat->is_reset_pending = FALSE;
427 	ioat->is_channel_running = FALSE;
428 
429 	bus_dma_tag_create(bus_get_dma_tag(ioat->device), sizeof(uint64_t), 0x0,
430 	    BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL,
431 	    sizeof(uint64_t), 1, sizeof(uint64_t), 0, NULL, NULL,
432 	    &ioat->comp_update_tag);
433 
434 	error = bus_dmamem_alloc(ioat->comp_update_tag,
435 	    (void **)&ioat->comp_update, BUS_DMA_ZERO, &ioat->comp_update_map);
436 	if (ioat->comp_update == NULL)
437 		return (ENOMEM);
438 
439 	error = bus_dmamap_load(ioat->comp_update_tag, ioat->comp_update_map,
440 	    ioat->comp_update, sizeof(uint64_t), ioat_comp_update_map, ioat,
441 	    0);
442 	if (error != 0)
443 		return (error);
444 
445 	ioat->ring_size_order = IOAT_MIN_ORDER;
446 
447 	num_descriptors = 1 << ioat->ring_size_order;
448 
449 	bus_dma_tag_create(bus_get_dma_tag(ioat->device), 0x40, 0x0,
450 	    BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL,
451 	    sizeof(struct ioat_dma_hw_descriptor), 1,
452 	    sizeof(struct ioat_dma_hw_descriptor), 0, NULL, NULL,
453 	    &ioat->hw_desc_tag);
454 
455 	ioat->ring = malloc(num_descriptors * sizeof(*ring), M_IOAT,
456 	    M_ZERO | M_WAITOK);
457 	if (ioat->ring == NULL)
458 		return (ENOMEM);
459 
460 	ring = ioat->ring;
461 	for (i = 0; i < num_descriptors; i++) {
462 		ring[i] = ioat_alloc_ring_entry(ioat, M_WAITOK);
463 		if (ring[i] == NULL)
464 			return (ENOMEM);
465 
466 		ring[i]->id = i;
467 	}
468 
469 	for (i = 0; i < num_descriptors - 1; i++) {
470 		next = ring[i + 1];
471 		dma_hw_desc = ring[i]->u.dma;
472 
473 		dma_hw_desc->next = next->hw_desc_bus_addr;
474 	}
475 
476 	ring[i]->u.dma->next = ring[0]->hw_desc_bus_addr;
477 
478 	ioat->head = ioat->hw_head = 0;
479 	ioat->tail = 0;
480 	ioat->last_seen = 0;
481 	return (0);
482 }
483 
484 static int
485 ioat_map_pci_bar(struct ioat_softc *ioat)
486 {
487 
488 	ioat->pci_resource_id = PCIR_BAR(0);
489 	ioat->pci_resource = bus_alloc_resource_any(ioat->device,
490 	    SYS_RES_MEMORY, &ioat->pci_resource_id, RF_ACTIVE);
491 
492 	if (ioat->pci_resource == NULL) {
493 		ioat_log_message(0, "unable to allocate pci resource\n");
494 		return (ENODEV);
495 	}
496 
497 	ioat->pci_bus_tag = rman_get_bustag(ioat->pci_resource);
498 	ioat->pci_bus_handle = rman_get_bushandle(ioat->pci_resource);
499 	return (0);
500 }
501 
502 static void
503 ioat_comp_update_map(void *arg, bus_dma_segment_t *seg, int nseg, int error)
504 {
505 	struct ioat_softc *ioat = arg;
506 
507 	KASSERT(error == 0, ("%s: error:%d", __func__, error));
508 	ioat->comp_update_bus_addr = seg[0].ds_addr;
509 }
510 
511 static void
512 ioat_dmamap_cb(void *arg, bus_dma_segment_t *segs, int nseg, int error)
513 {
514 	bus_addr_t *baddr;
515 
516 	KASSERT(error == 0, ("%s: error:%d", __func__, error));
517 	baddr = arg;
518 	*baddr = segs->ds_addr;
519 }
520 
521 /*
522  * Interrupt setup and handlers
523  */
524 static int
525 ioat_setup_intr(struct ioat_softc *ioat)
526 {
527 	uint32_t num_vectors;
528 	int error;
529 	boolean_t use_msix;
530 	boolean_t force_legacy_interrupts;
531 
532 	use_msix = FALSE;
533 	force_legacy_interrupts = FALSE;
534 
535 	if (!g_force_legacy_interrupts && pci_msix_count(ioat->device) >= 1) {
536 		num_vectors = 1;
537 		pci_alloc_msix(ioat->device, &num_vectors);
538 		if (num_vectors == 1)
539 			use_msix = TRUE;
540 	}
541 
542 	if (use_msix) {
543 		ioat->rid = 1;
544 		ioat->res = bus_alloc_resource_any(ioat->device, SYS_RES_IRQ,
545 		    &ioat->rid, RF_ACTIVE);
546 	} else {
547 		ioat->rid = 0;
548 		ioat->res = bus_alloc_resource_any(ioat->device, SYS_RES_IRQ,
549 		    &ioat->rid, RF_SHAREABLE | RF_ACTIVE);
550 	}
551 	if (ioat->res == NULL) {
552 		ioat_log_message(0, "bus_alloc_resource failed\n");
553 		return (ENOMEM);
554 	}
555 
556 	ioat->tag = NULL;
557 	error = bus_setup_intr(ioat->device, ioat->res, INTR_MPSAFE |
558 	    INTR_TYPE_MISC, NULL, ioat_interrupt_handler, ioat, &ioat->tag);
559 	if (error != 0) {
560 		ioat_log_message(0, "bus_setup_intr failed\n");
561 		return (error);
562 	}
563 
564 	ioat_write_intrctrl(ioat, IOAT_INTRCTRL_MASTER_INT_EN);
565 	return (0);
566 }
567 
568 static boolean_t
569 ioat_model_resets_msix(struct ioat_softc *ioat)
570 {
571 	u_int32_t pciid;
572 
573 	pciid = pci_get_devid(ioat->device);
574 	switch (pciid) {
575 		/* BWD: */
576 	case 0x0c508086:
577 	case 0x0c518086:
578 	case 0x0c528086:
579 	case 0x0c538086:
580 		/* BDXDE: */
581 	case 0x6f508086:
582 	case 0x6f518086:
583 	case 0x6f528086:
584 	case 0x6f538086:
585 		return (TRUE);
586 	}
587 
588 	return (FALSE);
589 }
590 
591 static void
592 ioat_interrupt_handler(void *arg)
593 {
594 	struct ioat_softc *ioat = arg;
595 
596 	ioat->stats.interrupts++;
597 	ioat_process_events(ioat);
598 }
599 
600 static int
601 chanerr_to_errno(uint32_t chanerr)
602 {
603 
604 	if (chanerr == 0)
605 		return (0);
606 	if ((chanerr & (IOAT_CHANERR_XSADDERR | IOAT_CHANERR_XDADDERR)) != 0)
607 		return (EFAULT);
608 	if ((chanerr & (IOAT_CHANERR_RDERR | IOAT_CHANERR_WDERR)) != 0)
609 		return (EIO);
610 	/* This one is probably our fault: */
611 	if ((chanerr & IOAT_CHANERR_NDADDERR) != 0)
612 		return (EIO);
613 	return (EIO);
614 }
615 
616 static void
617 ioat_process_events(struct ioat_softc *ioat)
618 {
619 	struct ioat_descriptor *desc;
620 	struct bus_dmadesc *dmadesc;
621 	uint64_t comp_update, status;
622 	uint32_t completed, chanerr;
623 	int error;
624 
625 	mtx_lock(&ioat->cleanup_lock);
626 
627 	completed = 0;
628 	comp_update = *ioat->comp_update;
629 	status = comp_update & IOAT_CHANSTS_COMPLETED_DESCRIPTOR_MASK;
630 
631 	CTR0(KTR_IOAT, __func__);
632 
633 	if (status == ioat->last_seen)
634 		goto out;
635 
636 	while (1) {
637 		desc = ioat_get_ring_entry(ioat, ioat->tail);
638 		dmadesc = &desc->bus_dmadesc;
639 		CTR1(KTR_IOAT, "completing desc %d", ioat->tail);
640 
641 		if (dmadesc->callback_fn != NULL)
642 			dmadesc->callback_fn(dmadesc->callback_arg, 0);
643 
644 		completed++;
645 		ioat->tail++;
646 		if (desc->hw_desc_bus_addr == status)
647 			break;
648 	}
649 
650 	ioat->last_seen = desc->hw_desc_bus_addr;
651 
652 	if (ioat->head == ioat->tail) {
653 		ioat->is_completion_pending = FALSE;
654 		callout_reset(&ioat->timer, IOAT_INTR_TIMO,
655 		    ioat_timer_callback, ioat);
656 	}
657 
658 	ioat->stats.descriptors_processed += completed;
659 
660 out:
661 	ioat_write_chanctrl(ioat, IOAT_CHANCTRL_RUN);
662 	mtx_unlock(&ioat->cleanup_lock);
663 
664 	ioat_putn(ioat, completed, IOAT_ACTIVE_DESCR_REF);
665 	wakeup(&ioat->tail);
666 
667 	if (!is_ioat_halted(comp_update))
668 		return;
669 
670 	ioat->stats.channel_halts++;
671 
672 	/*
673 	 * Fatal programming error on this DMA channel.  Flush any outstanding
674 	 * work with error status and restart the engine.
675 	 */
676 	ioat_log_message(0, "Channel halted due to fatal programming error\n");
677 	mtx_lock(&ioat->submit_lock);
678 	mtx_lock(&ioat->cleanup_lock);
679 	ioat->quiescing = TRUE;
680 
681 	chanerr = ioat_read_4(ioat, IOAT_CHANERR_OFFSET);
682 	ioat_halted_debug(ioat, chanerr);
683 	ioat->stats.last_halt_chanerr = chanerr;
684 
685 	while (ioat_get_active(ioat) > 0) {
686 		desc = ioat_get_ring_entry(ioat, ioat->tail);
687 		dmadesc = &desc->bus_dmadesc;
688 		CTR1(KTR_IOAT, "completing err desc %d", ioat->tail);
689 
690 		if (dmadesc->callback_fn != NULL)
691 			dmadesc->callback_fn(dmadesc->callback_arg,
692 			    chanerr_to_errno(chanerr));
693 
694 		ioat_putn_locked(ioat, 1, IOAT_ACTIVE_DESCR_REF);
695 		ioat->tail++;
696 		ioat->stats.descriptors_processed++;
697 		ioat->stats.descriptors_error++;
698 	}
699 
700 	/* Clear error status */
701 	ioat_write_4(ioat, IOAT_CHANERR_OFFSET, chanerr);
702 
703 	mtx_unlock(&ioat->cleanup_lock);
704 	mtx_unlock(&ioat->submit_lock);
705 
706 	ioat_log_message(0, "Resetting channel to recover from error\n");
707 	error = ioat_reset_hw(ioat);
708 	KASSERT(error == 0, ("%s: reset failed: %d", __func__, error));
709 }
710 
711 /*
712  * User API functions
713  */
714 bus_dmaengine_t
715 ioat_get_dmaengine(uint32_t index)
716 {
717 	struct ioat_softc *sc;
718 
719 	if (index >= ioat_channel_index)
720 		return (NULL);
721 
722 	sc = ioat_channel[index];
723 	if (sc == NULL || sc->quiescing)
724 		return (NULL);
725 
726 	return (&ioat_get(sc, IOAT_DMAENGINE_REF)->dmaengine);
727 }
728 
729 void
730 ioat_put_dmaengine(bus_dmaengine_t dmaengine)
731 {
732 	struct ioat_softc *ioat;
733 
734 	ioat = to_ioat_softc(dmaengine);
735 	ioat_put(ioat, IOAT_DMAENGINE_REF);
736 }
737 
738 int
739 ioat_get_hwversion(bus_dmaengine_t dmaengine)
740 {
741 	struct ioat_softc *ioat;
742 
743 	ioat = to_ioat_softc(dmaengine);
744 	return (ioat->version);
745 }
746 
747 size_t
748 ioat_get_max_io_size(bus_dmaengine_t dmaengine)
749 {
750 	struct ioat_softc *ioat;
751 
752 	ioat = to_ioat_softc(dmaengine);
753 	return (ioat->max_xfer_size);
754 }
755 
756 int
757 ioat_set_interrupt_coalesce(bus_dmaengine_t dmaengine, uint16_t delay)
758 {
759 	struct ioat_softc *ioat;
760 
761 	ioat = to_ioat_softc(dmaengine);
762 	if (!ioat->intrdelay_supported)
763 		return (ENODEV);
764 	if (delay > ioat->intrdelay_max)
765 		return (ERANGE);
766 
767 	ioat_write_2(ioat, IOAT_INTRDELAY_OFFSET, delay);
768 	ioat->cached_intrdelay =
769 	    ioat_read_2(ioat, IOAT_INTRDELAY_OFFSET) & IOAT_INTRDELAY_US_MASK;
770 	return (0);
771 }
772 
773 uint16_t
774 ioat_get_max_coalesce_period(bus_dmaengine_t dmaengine)
775 {
776 	struct ioat_softc *ioat;
777 
778 	ioat = to_ioat_softc(dmaengine);
779 	return (ioat->intrdelay_max);
780 }
781 
782 void
783 ioat_acquire(bus_dmaengine_t dmaengine)
784 {
785 	struct ioat_softc *ioat;
786 
787 	ioat = to_ioat_softc(dmaengine);
788 	mtx_lock(&ioat->submit_lock);
789 	CTR0(KTR_IOAT, __func__);
790 }
791 
792 int
793 ioat_acquire_reserve(bus_dmaengine_t dmaengine, unsigned n, int mflags)
794 {
795 	struct ioat_softc *ioat;
796 	int error;
797 
798 	ioat = to_ioat_softc(dmaengine);
799 	ioat_acquire(dmaengine);
800 
801 	error = ioat_reserve_space(ioat, n, mflags);
802 	if (error != 0)
803 		ioat_release(dmaengine);
804 	return (error);
805 }
806 
807 void
808 ioat_release(bus_dmaengine_t dmaengine)
809 {
810 	struct ioat_softc *ioat;
811 
812 	ioat = to_ioat_softc(dmaengine);
813 	CTR0(KTR_IOAT, __func__);
814 	ioat_write_2(ioat, IOAT_DMACOUNT_OFFSET, (uint16_t)ioat->hw_head);
815 	mtx_unlock(&ioat->submit_lock);
816 }
817 
818 static struct ioat_descriptor *
819 ioat_op_generic(struct ioat_softc *ioat, uint8_t op,
820     uint32_t size, uint64_t src, uint64_t dst,
821     bus_dmaengine_callback_t callback_fn, void *callback_arg,
822     uint32_t flags)
823 {
824 	struct ioat_generic_hw_descriptor *hw_desc;
825 	struct ioat_descriptor *desc;
826 	int mflags;
827 
828 	mtx_assert(&ioat->submit_lock, MA_OWNED);
829 
830 	KASSERT((flags & ~DMA_ALL_FLAGS) == 0, ("Unrecognized flag(s): %#x",
831 		flags & ~DMA_ALL_FLAGS));
832 	if ((flags & DMA_NO_WAIT) != 0)
833 		mflags = M_NOWAIT;
834 	else
835 		mflags = M_WAITOK;
836 
837 	if (size > ioat->max_xfer_size) {
838 		ioat_log_message(0, "%s: max_xfer_size = %d, requested = %u\n",
839 		    __func__, ioat->max_xfer_size, (unsigned)size);
840 		return (NULL);
841 	}
842 
843 	if (ioat_reserve_space(ioat, 1, mflags) != 0)
844 		return (NULL);
845 
846 	desc = ioat_get_ring_entry(ioat, ioat->head);
847 	hw_desc = desc->u.generic;
848 
849 	hw_desc->u.control_raw = 0;
850 	hw_desc->u.control_generic.op = op;
851 	hw_desc->u.control_generic.completion_update = 1;
852 
853 	if ((flags & DMA_INT_EN) != 0)
854 		hw_desc->u.control_generic.int_enable = 1;
855 
856 	hw_desc->size = size;
857 	hw_desc->src_addr = src;
858 	hw_desc->dest_addr = dst;
859 
860 	desc->bus_dmadesc.callback_fn = callback_fn;
861 	desc->bus_dmadesc.callback_arg = callback_arg;
862 	return (desc);
863 }
864 
865 struct bus_dmadesc *
866 ioat_null(bus_dmaengine_t dmaengine, bus_dmaengine_callback_t callback_fn,
867     void *callback_arg, uint32_t flags)
868 {
869 	struct ioat_dma_hw_descriptor *hw_desc;
870 	struct ioat_descriptor *desc;
871 	struct ioat_softc *ioat;
872 
873 	CTR0(KTR_IOAT, __func__);
874 	ioat = to_ioat_softc(dmaengine);
875 
876 	desc = ioat_op_generic(ioat, IOAT_OP_COPY, 8, 0, 0, callback_fn,
877 	    callback_arg, flags);
878 	if (desc == NULL)
879 		return (NULL);
880 
881 	hw_desc = desc->u.dma;
882 	hw_desc->u.control.null = 1;
883 	ioat_submit_single(ioat);
884 	return (&desc->bus_dmadesc);
885 }
886 
887 struct bus_dmadesc *
888 ioat_copy(bus_dmaengine_t dmaengine, bus_addr_t dst,
889     bus_addr_t src, bus_size_t len, bus_dmaengine_callback_t callback_fn,
890     void *callback_arg, uint32_t flags)
891 {
892 	struct ioat_dma_hw_descriptor *hw_desc;
893 	struct ioat_descriptor *desc;
894 	struct ioat_softc *ioat;
895 
896 	CTR0(KTR_IOAT, __func__);
897 	ioat = to_ioat_softc(dmaengine);
898 
899 	if (((src | dst) & (0xffffull << 48)) != 0) {
900 		ioat_log_message(0, "%s: High 16 bits of src/dst invalid\n",
901 		    __func__);
902 		return (NULL);
903 	}
904 
905 	desc = ioat_op_generic(ioat, IOAT_OP_COPY, len, src, dst, callback_fn,
906 	    callback_arg, flags);
907 	if (desc == NULL)
908 		return (NULL);
909 
910 	hw_desc = desc->u.dma;
911 	if (g_ioat_debug_level >= 3)
912 		dump_descriptor(hw_desc);
913 
914 	ioat_submit_single(ioat);
915 	return (&desc->bus_dmadesc);
916 }
917 
918 struct bus_dmadesc *
919 ioat_copy_8k_aligned(bus_dmaengine_t dmaengine, bus_addr_t dst1,
920     bus_addr_t dst2, bus_addr_t src1, bus_addr_t src2,
921     bus_dmaengine_callback_t callback_fn, void *callback_arg, uint32_t flags)
922 {
923 	struct ioat_dma_hw_descriptor *hw_desc;
924 	struct ioat_descriptor *desc;
925 	struct ioat_softc *ioat;
926 
927 	CTR0(KTR_IOAT, __func__);
928 	ioat = to_ioat_softc(dmaengine);
929 
930 	if (((src1 | src2 | dst1 | dst2) & (0xffffull << 48)) != 0) {
931 		ioat_log_message(0, "%s: High 16 bits of src/dst invalid\n",
932 		    __func__);
933 		return (NULL);
934 	}
935 	if (((src1 | src2 | dst1 | dst2) & PAGE_MASK) != 0) {
936 		ioat_log_message(0, "%s: Addresses must be page-aligned\n",
937 		    __func__);
938 		return (NULL);
939 	}
940 
941 	desc = ioat_op_generic(ioat, IOAT_OP_COPY, 2 * PAGE_SIZE, src1, dst1,
942 	    callback_fn, callback_arg, flags);
943 	if (desc == NULL)
944 		return (NULL);
945 
946 	hw_desc = desc->u.dma;
947 	if (src2 != src1 + PAGE_SIZE) {
948 		hw_desc->u.control.src_page_break = 1;
949 		hw_desc->next_src_addr = src2;
950 	}
951 	if (dst2 != dst1 + PAGE_SIZE) {
952 		hw_desc->u.control.dest_page_break = 1;
953 		hw_desc->next_dest_addr = dst2;
954 	}
955 
956 	if (g_ioat_debug_level >= 3)
957 		dump_descriptor(hw_desc);
958 
959 	ioat_submit_single(ioat);
960 	return (&desc->bus_dmadesc);
961 }
962 
963 struct bus_dmadesc *
964 ioat_blockfill(bus_dmaengine_t dmaengine, bus_addr_t dst, uint64_t fillpattern,
965     bus_size_t len, bus_dmaengine_callback_t callback_fn, void *callback_arg,
966     uint32_t flags)
967 {
968 	struct ioat_fill_hw_descriptor *hw_desc;
969 	struct ioat_descriptor *desc;
970 	struct ioat_softc *ioat;
971 
972 	CTR0(KTR_IOAT, __func__);
973 	ioat = to_ioat_softc(dmaengine);
974 
975 	if ((ioat->capabilities & IOAT_DMACAP_BFILL) == 0) {
976 		ioat_log_message(0, "%s: Device lacks BFILL capability\n",
977 		    __func__);
978 		return (NULL);
979 	}
980 
981 	if ((dst & (0xffffull << 48)) != 0) {
982 		ioat_log_message(0, "%s: High 16 bits of dst invalid\n",
983 		    __func__);
984 		return (NULL);
985 	}
986 
987 	desc = ioat_op_generic(ioat, IOAT_OP_FILL, len, fillpattern, dst,
988 	    callback_fn, callback_arg, flags);
989 	if (desc == NULL)
990 		return (NULL);
991 
992 	hw_desc = desc->u.fill;
993 	if (g_ioat_debug_level >= 3)
994 		dump_descriptor(hw_desc);
995 
996 	ioat_submit_single(ioat);
997 	return (&desc->bus_dmadesc);
998 }
999 
1000 /*
1001  * Ring Management
1002  */
1003 static inline uint32_t
1004 ioat_get_active(struct ioat_softc *ioat)
1005 {
1006 
1007 	return ((ioat->head - ioat->tail) & ((1 << ioat->ring_size_order) - 1));
1008 }
1009 
1010 static inline uint32_t
1011 ioat_get_ring_space(struct ioat_softc *ioat)
1012 {
1013 
1014 	return ((1 << ioat->ring_size_order) - ioat_get_active(ioat) - 1);
1015 }
1016 
1017 static struct ioat_descriptor *
1018 ioat_alloc_ring_entry(struct ioat_softc *ioat, int mflags)
1019 {
1020 	struct ioat_generic_hw_descriptor *hw_desc;
1021 	struct ioat_descriptor *desc;
1022 	int error, busdmaflag;
1023 
1024 	error = ENOMEM;
1025 	hw_desc = NULL;
1026 
1027 	if ((mflags & M_WAITOK) != 0)
1028 		busdmaflag = BUS_DMA_WAITOK;
1029 	else
1030 		busdmaflag = BUS_DMA_NOWAIT;
1031 
1032 	desc = malloc(sizeof(*desc), M_IOAT, mflags);
1033 	if (desc == NULL)
1034 		goto out;
1035 
1036 	bus_dmamem_alloc(ioat->hw_desc_tag, (void **)&hw_desc,
1037 	    BUS_DMA_ZERO | busdmaflag, &ioat->hw_desc_map);
1038 	if (hw_desc == NULL)
1039 		goto out;
1040 
1041 	memset(&desc->bus_dmadesc, 0, sizeof(desc->bus_dmadesc));
1042 	desc->u.generic = hw_desc;
1043 
1044 	error = bus_dmamap_load(ioat->hw_desc_tag, ioat->hw_desc_map, hw_desc,
1045 	    sizeof(*hw_desc), ioat_dmamap_cb, &desc->hw_desc_bus_addr,
1046 	    busdmaflag);
1047 	if (error)
1048 		goto out;
1049 
1050 out:
1051 	if (error) {
1052 		ioat_free_ring_entry(ioat, desc);
1053 		return (NULL);
1054 	}
1055 	return (desc);
1056 }
1057 
1058 static void
1059 ioat_free_ring_entry(struct ioat_softc *ioat, struct ioat_descriptor *desc)
1060 {
1061 
1062 	if (desc == NULL)
1063 		return;
1064 
1065 	if (desc->u.generic)
1066 		bus_dmamem_free(ioat->hw_desc_tag, desc->u.generic,
1067 		    ioat->hw_desc_map);
1068 	free(desc, M_IOAT);
1069 }
1070 
1071 /*
1072  * Reserves space in this IOAT descriptor ring by ensuring enough slots remain
1073  * for 'num_descs'.
1074  *
1075  * If mflags contains M_WAITOK, blocks until enough space is available.
1076  *
1077  * Returns zero on success, or an errno on error.  If num_descs is beyond the
1078  * maximum ring size, returns EINVAl; if allocation would block and mflags
1079  * contains M_NOWAIT, returns EAGAIN.
1080  *
1081  * Must be called with the submit_lock held; returns with the lock held.  The
1082  * lock may be dropped to allocate the ring.
1083  *
1084  * (The submit_lock is needed to add any entries to the ring, so callers are
1085  * assured enough room is available.)
1086  */
1087 static int
1088 ioat_reserve_space(struct ioat_softc *ioat, uint32_t num_descs, int mflags)
1089 {
1090 	struct ioat_descriptor **new_ring;
1091 	uint32_t order;
1092 	int error;
1093 
1094 	mtx_assert(&ioat->submit_lock, MA_OWNED);
1095 	error = 0;
1096 
1097 	if (num_descs < 1 || num_descs > (1 << IOAT_MAX_ORDER)) {
1098 		error = EINVAL;
1099 		goto out;
1100 	}
1101 	if (ioat->quiescing) {
1102 		error = ENXIO;
1103 		goto out;
1104 	}
1105 
1106 	for (;;) {
1107 		if (ioat_get_ring_space(ioat) >= num_descs)
1108 			goto out;
1109 
1110 		order = ioat->ring_size_order;
1111 		if (ioat->is_resize_pending || order == IOAT_MAX_ORDER) {
1112 			if ((mflags & M_WAITOK) != 0) {
1113 				msleep(&ioat->tail, &ioat->submit_lock, 0,
1114 				    "ioat_rsz", 0);
1115 				continue;
1116 			}
1117 
1118 			error = EAGAIN;
1119 			break;
1120 		}
1121 
1122 		ioat->is_resize_pending = TRUE;
1123 		for (;;) {
1124 			mtx_unlock(&ioat->submit_lock);
1125 
1126 			new_ring = ioat_prealloc_ring(ioat, 1 << (order + 1),
1127 			    TRUE, mflags);
1128 
1129 			mtx_lock(&ioat->submit_lock);
1130 			KASSERT(ioat->ring_size_order == order,
1131 			    ("is_resize_pending should protect order"));
1132 
1133 			if (new_ring == NULL) {
1134 				KASSERT((mflags & M_WAITOK) == 0,
1135 				    ("allocation failed"));
1136 				error = EAGAIN;
1137 				break;
1138 			}
1139 
1140 			error = ring_grow(ioat, order, new_ring);
1141 			if (error == 0)
1142 				break;
1143 		}
1144 		ioat->is_resize_pending = FALSE;
1145 		wakeup(&ioat->tail);
1146 		if (error)
1147 			break;
1148 	}
1149 
1150 out:
1151 	mtx_assert(&ioat->submit_lock, MA_OWNED);
1152 	return (error);
1153 }
1154 
1155 static struct ioat_descriptor **
1156 ioat_prealloc_ring(struct ioat_softc *ioat, uint32_t size, boolean_t need_dscr,
1157     int mflags)
1158 {
1159 	struct ioat_descriptor **ring;
1160 	uint32_t i;
1161 	int error;
1162 
1163 	KASSERT(size > 0 && powerof2(size), ("bogus size"));
1164 
1165 	ring = malloc(size * sizeof(*ring), M_IOAT, M_ZERO | mflags);
1166 	if (ring == NULL)
1167 		return (NULL);
1168 
1169 	if (need_dscr) {
1170 		error = ENOMEM;
1171 		for (i = size / 2; i < size; i++) {
1172 			ring[i] = ioat_alloc_ring_entry(ioat, mflags);
1173 			if (ring[i] == NULL)
1174 				goto out;
1175 			ring[i]->id = i;
1176 		}
1177 	}
1178 	error = 0;
1179 
1180 out:
1181 	if (error != 0 && ring != NULL) {
1182 		ioat_free_ring(ioat, size, ring);
1183 		ring = NULL;
1184 	}
1185 	return (ring);
1186 }
1187 
1188 static void
1189 ioat_free_ring(struct ioat_softc *ioat, uint32_t size,
1190     struct ioat_descriptor **ring)
1191 {
1192 	uint32_t i;
1193 
1194 	for (i = 0; i < size; i++) {
1195 		if (ring[i] != NULL)
1196 			ioat_free_ring_entry(ioat, ring[i]);
1197 	}
1198 	free(ring, M_IOAT);
1199 }
1200 
1201 static struct ioat_descriptor *
1202 ioat_get_ring_entry(struct ioat_softc *ioat, uint32_t index)
1203 {
1204 
1205 	return (ioat->ring[index % (1 << ioat->ring_size_order)]);
1206 }
1207 
1208 static int
1209 ring_grow(struct ioat_softc *ioat, uint32_t oldorder,
1210     struct ioat_descriptor **newring)
1211 {
1212 	struct ioat_descriptor *tmp, *next;
1213 	struct ioat_dma_hw_descriptor *hw;
1214 	uint32_t oldsize, newsize, head, tail, i, end;
1215 	int error;
1216 
1217 	CTR0(KTR_IOAT, __func__);
1218 
1219 	mtx_assert(&ioat->submit_lock, MA_OWNED);
1220 
1221 	if (oldorder != ioat->ring_size_order || oldorder >= IOAT_MAX_ORDER) {
1222 		error = EINVAL;
1223 		goto out;
1224 	}
1225 
1226 	oldsize = (1 << oldorder);
1227 	newsize = (1 << (oldorder + 1));
1228 
1229 	mtx_lock(&ioat->cleanup_lock);
1230 
1231 	head = ioat->head & (oldsize - 1);
1232 	tail = ioat->tail & (oldsize - 1);
1233 
1234 	/* Copy old descriptors to new ring */
1235 	for (i = 0; i < oldsize; i++)
1236 		newring[i] = ioat->ring[i];
1237 
1238 	/*
1239 	 * If head has wrapped but tail hasn't, we must swap some descriptors
1240 	 * around so that tail can increment directly to head.
1241 	 */
1242 	if (head < tail) {
1243 		for (i = 0; i <= head; i++) {
1244 			tmp = newring[oldsize + i];
1245 
1246 			newring[oldsize + i] = newring[i];
1247 			newring[oldsize + i]->id = oldsize + i;
1248 
1249 			newring[i] = tmp;
1250 			newring[i]->id = i;
1251 		}
1252 		head += oldsize;
1253 	}
1254 
1255 	KASSERT(head >= tail, ("invariants"));
1256 
1257 	/* Head didn't wrap; we only need to link in oldsize..newsize */
1258 	if (head < oldsize) {
1259 		i = oldsize - 1;
1260 		end = newsize;
1261 	} else {
1262 		/* Head did wrap; link newhead..newsize and 0..oldhead */
1263 		i = head;
1264 		end = newsize + (head - oldsize) + 1;
1265 	}
1266 
1267 	/*
1268 	 * Fix up hardware ring, being careful not to trample the active
1269 	 * section (tail -> head).
1270 	 */
1271 	for (; i < end; i++) {
1272 		KASSERT((i & (newsize - 1)) < tail ||
1273 		    (i & (newsize - 1)) >= head, ("trampling snake"));
1274 
1275 		next = newring[(i + 1) & (newsize - 1)];
1276 		hw = newring[i & (newsize - 1)]->u.dma;
1277 		hw->next = next->hw_desc_bus_addr;
1278 	}
1279 
1280 	free(ioat->ring, M_IOAT);
1281 	ioat->ring = newring;
1282 	ioat->ring_size_order = oldorder + 1;
1283 	ioat->tail = tail;
1284 	ioat->head = head;
1285 	error = 0;
1286 
1287 	mtx_unlock(&ioat->cleanup_lock);
1288 out:
1289 	if (error)
1290 		ioat_free_ring(ioat, (1 << (oldorder + 1)), newring);
1291 	return (error);
1292 }
1293 
1294 static int
1295 ring_shrink(struct ioat_softc *ioat, uint32_t oldorder,
1296     struct ioat_descriptor **newring)
1297 {
1298 	struct ioat_dma_hw_descriptor *hw;
1299 	struct ioat_descriptor *ent, *next;
1300 	uint32_t oldsize, newsize, current_idx, new_idx, i;
1301 	int error;
1302 
1303 	CTR0(KTR_IOAT, __func__);
1304 
1305 	mtx_assert(&ioat->submit_lock, MA_OWNED);
1306 
1307 	if (oldorder != ioat->ring_size_order || oldorder <= IOAT_MIN_ORDER) {
1308 		error = EINVAL;
1309 		goto out_unlocked;
1310 	}
1311 
1312 	oldsize = (1 << oldorder);
1313 	newsize = (1 << (oldorder - 1));
1314 
1315 	mtx_lock(&ioat->cleanup_lock);
1316 
1317 	/* Can't shrink below current active set! */
1318 	if (ioat_get_active(ioat) >= newsize) {
1319 		error = ENOMEM;
1320 		goto out;
1321 	}
1322 
1323 	/*
1324 	 * Copy current descriptors to the new ring, dropping the removed
1325 	 * descriptors.
1326 	 */
1327 	for (i = 0; i < newsize; i++) {
1328 		current_idx = (ioat->tail + i) & (oldsize - 1);
1329 		new_idx = (ioat->tail + i) & (newsize - 1);
1330 
1331 		newring[new_idx] = ioat->ring[current_idx];
1332 		newring[new_idx]->id = new_idx;
1333 	}
1334 
1335 	/* Free deleted descriptors */
1336 	for (i = newsize; i < oldsize; i++) {
1337 		ent = ioat_get_ring_entry(ioat, ioat->tail + i);
1338 		ioat_free_ring_entry(ioat, ent);
1339 	}
1340 
1341 	/* Fix up hardware ring. */
1342 	hw = newring[(ioat->tail + newsize - 1) & (newsize - 1)]->u.dma;
1343 	next = newring[(ioat->tail + newsize) & (newsize - 1)];
1344 	hw->next = next->hw_desc_bus_addr;
1345 
1346 	free(ioat->ring, M_IOAT);
1347 	ioat->ring = newring;
1348 	ioat->ring_size_order = oldorder - 1;
1349 	error = 0;
1350 
1351 out:
1352 	mtx_unlock(&ioat->cleanup_lock);
1353 out_unlocked:
1354 	if (error)
1355 		ioat_free_ring(ioat, (1 << (oldorder - 1)), newring);
1356 	return (error);
1357 }
1358 
1359 static void
1360 ioat_halted_debug(struct ioat_softc *ioat, uint32_t chanerr)
1361 {
1362 	struct ioat_descriptor *desc;
1363 
1364 	ioat_log_message(0, "Channel halted (%b)\n", (int)chanerr,
1365 	    IOAT_CHANERR_STR);
1366 	if (chanerr == 0)
1367 		return;
1368 
1369 	mtx_assert(&ioat->cleanup_lock, MA_OWNED);
1370 
1371 	desc = ioat_get_ring_entry(ioat, ioat->tail + 0);
1372 	dump_descriptor(desc->u.raw);
1373 
1374 	desc = ioat_get_ring_entry(ioat, ioat->tail + 1);
1375 	dump_descriptor(desc->u.raw);
1376 }
1377 
1378 static void
1379 ioat_timer_callback(void *arg)
1380 {
1381 	struct ioat_descriptor **newring;
1382 	struct ioat_softc *ioat;
1383 	uint32_t order;
1384 
1385 	ioat = arg;
1386 	ioat_log_message(1, "%s\n", __func__);
1387 
1388 	if (ioat->is_completion_pending) {
1389 		ioat_process_events(ioat);
1390 		return;
1391 	}
1392 
1393 	/* Slowly scale the ring down if idle. */
1394 	mtx_lock(&ioat->submit_lock);
1395 	order = ioat->ring_size_order;
1396 	if (ioat->is_resize_pending || order == IOAT_MIN_ORDER) {
1397 		mtx_unlock(&ioat->submit_lock);
1398 		goto out;
1399 	}
1400 	ioat->is_resize_pending = TRUE;
1401 	mtx_unlock(&ioat->submit_lock);
1402 
1403 	newring = ioat_prealloc_ring(ioat, 1 << (order - 1), FALSE,
1404 	    M_NOWAIT);
1405 
1406 	mtx_lock(&ioat->submit_lock);
1407 	KASSERT(ioat->ring_size_order == order,
1408 	    ("resize_pending protects order"));
1409 
1410 	if (newring != NULL)
1411 		ring_shrink(ioat, order, newring);
1412 
1413 	ioat->is_resize_pending = FALSE;
1414 	mtx_unlock(&ioat->submit_lock);
1415 
1416 out:
1417 	if (ioat->ring_size_order > IOAT_MIN_ORDER)
1418 		callout_reset(&ioat->timer, 10 * hz,
1419 		    ioat_timer_callback, ioat);
1420 }
1421 
1422 /*
1423  * Support Functions
1424  */
1425 static void
1426 ioat_submit_single(struct ioat_softc *ioat)
1427 {
1428 
1429 	ioat_get(ioat, IOAT_ACTIVE_DESCR_REF);
1430 	atomic_add_rel_int(&ioat->head, 1);
1431 	atomic_add_rel_int(&ioat->hw_head, 1);
1432 
1433 	if (!ioat->is_completion_pending) {
1434 		ioat->is_completion_pending = TRUE;
1435 		callout_reset(&ioat->timer, IOAT_INTR_TIMO,
1436 		    ioat_timer_callback, ioat);
1437 	}
1438 
1439 	ioat->stats.descriptors_submitted++;
1440 }
1441 
1442 static int
1443 ioat_reset_hw(struct ioat_softc *ioat)
1444 {
1445 	uint64_t status;
1446 	uint32_t chanerr;
1447 	unsigned timeout;
1448 	int error;
1449 
1450 	mtx_lock(IOAT_REFLK);
1451 	ioat->quiescing = TRUE;
1452 	ioat_drain_locked(ioat);
1453 	mtx_unlock(IOAT_REFLK);
1454 
1455 	status = ioat_get_chansts(ioat);
1456 	if (is_ioat_active(status) || is_ioat_idle(status))
1457 		ioat_suspend(ioat);
1458 
1459 	/* Wait at most 20 ms */
1460 	for (timeout = 0; (is_ioat_active(status) || is_ioat_idle(status)) &&
1461 	    timeout < 20; timeout++) {
1462 		DELAY(1000);
1463 		status = ioat_get_chansts(ioat);
1464 	}
1465 	if (timeout == 20) {
1466 		error = ETIMEDOUT;
1467 		goto out;
1468 	}
1469 
1470 	KASSERT(ioat_get_active(ioat) == 0, ("active after quiesce"));
1471 
1472 	chanerr = ioat_read_4(ioat, IOAT_CHANERR_OFFSET);
1473 	ioat_write_4(ioat, IOAT_CHANERR_OFFSET, chanerr);
1474 
1475 	/*
1476 	 * IOAT v3 workaround - CHANERRMSK_INT with 3E07h to masks out errors
1477 	 *  that can cause stability issues for IOAT v3.
1478 	 */
1479 	pci_write_config(ioat->device, IOAT_CFG_CHANERRMASK_INT_OFFSET, 0x3e07,
1480 	    4);
1481 	chanerr = pci_read_config(ioat->device, IOAT_CFG_CHANERR_INT_OFFSET, 4);
1482 	pci_write_config(ioat->device, IOAT_CFG_CHANERR_INT_OFFSET, chanerr, 4);
1483 
1484 	/*
1485 	 * BDXDE and BWD models reset MSI-X registers on device reset.
1486 	 * Save/restore their contents manually.
1487 	 */
1488 	if (ioat_model_resets_msix(ioat)) {
1489 		ioat_log_message(1, "device resets MSI-X registers; saving\n");
1490 		pci_save_state(ioat->device);
1491 	}
1492 
1493 	ioat_reset(ioat);
1494 
1495 	/* Wait at most 20 ms */
1496 	for (timeout = 0; ioat_reset_pending(ioat) && timeout < 20; timeout++)
1497 		DELAY(1000);
1498 	if (timeout == 20) {
1499 		error = ETIMEDOUT;
1500 		goto out;
1501 	}
1502 
1503 	if (ioat_model_resets_msix(ioat)) {
1504 		ioat_log_message(1, "device resets registers; restored\n");
1505 		pci_restore_state(ioat->device);
1506 	}
1507 
1508 	/* Reset attempts to return the hardware to "halted." */
1509 	status = ioat_get_chansts(ioat);
1510 	if (is_ioat_active(status) || is_ioat_idle(status)) {
1511 		/* So this really shouldn't happen... */
1512 		ioat_log_message(0, "Device is active after a reset?\n");
1513 		ioat_write_chanctrl(ioat, IOAT_CHANCTRL_RUN);
1514 		error = 0;
1515 		goto out;
1516 	}
1517 
1518 	chanerr = ioat_read_4(ioat, IOAT_CHANERR_OFFSET);
1519 	if (chanerr != 0) {
1520 		mtx_lock(&ioat->cleanup_lock);
1521 		ioat_halted_debug(ioat, chanerr);
1522 		mtx_unlock(&ioat->cleanup_lock);
1523 		error = EIO;
1524 		goto out;
1525 	}
1526 
1527 	/*
1528 	 * Bring device back online after reset.  Writing CHAINADDR brings the
1529 	 * device back to active.
1530 	 *
1531 	 * The internal ring counter resets to zero, so we have to start over
1532 	 * at zero as well.
1533 	 */
1534 	ioat->tail = ioat->head = ioat->hw_head = 0;
1535 	ioat->last_seen = 0;
1536 
1537 	ioat_write_chanctrl(ioat, IOAT_CHANCTRL_RUN);
1538 	ioat_write_chancmp(ioat, ioat->comp_update_bus_addr);
1539 	ioat_write_chainaddr(ioat, ioat->ring[0]->hw_desc_bus_addr);
1540 	error = 0;
1541 
1542 out:
1543 	mtx_lock(IOAT_REFLK);
1544 	ioat->quiescing = FALSE;
1545 	mtx_unlock(IOAT_REFLK);
1546 
1547 	if (error == 0)
1548 		error = ioat_start_channel(ioat);
1549 
1550 	return (error);
1551 }
1552 
1553 static int
1554 sysctl_handle_chansts(SYSCTL_HANDLER_ARGS)
1555 {
1556 	struct ioat_softc *ioat;
1557 	struct sbuf sb;
1558 	uint64_t status;
1559 	int error;
1560 
1561 	ioat = arg1;
1562 
1563 	status = ioat_get_chansts(ioat) & IOAT_CHANSTS_STATUS;
1564 
1565 	sbuf_new_for_sysctl(&sb, NULL, 256, req);
1566 	switch (status) {
1567 	case IOAT_CHANSTS_ACTIVE:
1568 		sbuf_printf(&sb, "ACTIVE");
1569 		break;
1570 	case IOAT_CHANSTS_IDLE:
1571 		sbuf_printf(&sb, "IDLE");
1572 		break;
1573 	case IOAT_CHANSTS_SUSPENDED:
1574 		sbuf_printf(&sb, "SUSPENDED");
1575 		break;
1576 	case IOAT_CHANSTS_HALTED:
1577 		sbuf_printf(&sb, "HALTED");
1578 		break;
1579 	case IOAT_CHANSTS_ARMED:
1580 		sbuf_printf(&sb, "ARMED");
1581 		break;
1582 	default:
1583 		sbuf_printf(&sb, "UNKNOWN");
1584 		break;
1585 	}
1586 	error = sbuf_finish(&sb);
1587 	sbuf_delete(&sb);
1588 
1589 	if (error != 0 || req->newptr == NULL)
1590 		return (error);
1591 	return (EINVAL);
1592 }
1593 
1594 static int
1595 sysctl_handle_dpi(SYSCTL_HANDLER_ARGS)
1596 {
1597 	struct ioat_softc *ioat;
1598 	struct sbuf sb;
1599 #define	PRECISION	"1"
1600 	const uintmax_t factor = 10;
1601 	uintmax_t rate;
1602 	int error;
1603 
1604 	ioat = arg1;
1605 	sbuf_new_for_sysctl(&sb, NULL, 16, req);
1606 
1607 	if (ioat->stats.interrupts == 0) {
1608 		sbuf_printf(&sb, "NaN");
1609 		goto out;
1610 	}
1611 	rate = ioat->stats.descriptors_processed * factor /
1612 	    ioat->stats.interrupts;
1613 	sbuf_printf(&sb, "%ju.%." PRECISION "ju", rate / factor,
1614 	    rate % factor);
1615 #undef	PRECISION
1616 out:
1617 	error = sbuf_finish(&sb);
1618 	sbuf_delete(&sb);
1619 	if (error != 0 || req->newptr == NULL)
1620 		return (error);
1621 	return (EINVAL);
1622 }
1623 
1624 static int
1625 sysctl_handle_error(SYSCTL_HANDLER_ARGS)
1626 {
1627 	struct ioat_descriptor *desc;
1628 	struct ioat_softc *ioat;
1629 	int error, arg;
1630 
1631 	ioat = arg1;
1632 
1633 	arg = 0;
1634 	error = SYSCTL_OUT(req, &arg, sizeof(arg));
1635 	if (error != 0 || req->newptr == NULL)
1636 		return (error);
1637 
1638 	error = SYSCTL_IN(req, &arg, sizeof(arg));
1639 	if (error != 0)
1640 		return (error);
1641 
1642 	if (arg != 0) {
1643 		ioat_acquire(&ioat->dmaengine);
1644 		desc = ioat_op_generic(ioat, IOAT_OP_COPY, 1,
1645 		    0xffff000000000000ull, 0xffff000000000000ull, NULL, NULL,
1646 		    0);
1647 		if (desc == NULL)
1648 			error = ENOMEM;
1649 		else
1650 			ioat_submit_single(ioat);
1651 		ioat_release(&ioat->dmaengine);
1652 	}
1653 	return (error);
1654 }
1655 
1656 static int
1657 sysctl_handle_reset(SYSCTL_HANDLER_ARGS)
1658 {
1659 	struct ioat_softc *ioat;
1660 	int error, arg;
1661 
1662 	ioat = arg1;
1663 
1664 	arg = 0;
1665 	error = SYSCTL_OUT(req, &arg, sizeof(arg));
1666 	if (error != 0 || req->newptr == NULL)
1667 		return (error);
1668 
1669 	error = SYSCTL_IN(req, &arg, sizeof(arg));
1670 	if (error != 0)
1671 		return (error);
1672 
1673 	if (arg != 0)
1674 		error = ioat_reset_hw(ioat);
1675 
1676 	return (error);
1677 }
1678 
1679 static void
1680 dump_descriptor(void *hw_desc)
1681 {
1682 	int i, j;
1683 
1684 	for (i = 0; i < 2; i++) {
1685 		for (j = 0; j < 8; j++)
1686 			printf("%08x ", ((uint32_t *)hw_desc)[i * 8 + j]);
1687 		printf("\n");
1688 	}
1689 }
1690 
1691 static void
1692 ioat_setup_sysctl(device_t device)
1693 {
1694 	struct sysctl_oid_list *par, *statpar, *state, *hammer;
1695 	struct sysctl_ctx_list *ctx;
1696 	struct sysctl_oid *tree, *tmp;
1697 	struct ioat_softc *ioat;
1698 
1699 	ioat = DEVICE2SOFTC(device);
1700 	ctx = device_get_sysctl_ctx(device);
1701 	tree = device_get_sysctl_tree(device);
1702 	par = SYSCTL_CHILDREN(tree);
1703 
1704 	SYSCTL_ADD_INT(ctx, par, OID_AUTO, "version", CTLFLAG_RD,
1705 	    &ioat->version, 0, "HW version (0xMM form)");
1706 	SYSCTL_ADD_UINT(ctx, par, OID_AUTO, "max_xfer_size", CTLFLAG_RD,
1707 	    &ioat->max_xfer_size, 0, "HW maximum transfer size");
1708 	SYSCTL_ADD_INT(ctx, par, OID_AUTO, "intrdelay_supported", CTLFLAG_RD,
1709 	    &ioat->intrdelay_supported, 0, "Is INTRDELAY supported");
1710 	SYSCTL_ADD_U16(ctx, par, OID_AUTO, "intrdelay_max", CTLFLAG_RD,
1711 	    &ioat->intrdelay_max, 0,
1712 	    "Maximum configurable INTRDELAY on this channel (microseconds)");
1713 
1714 	tmp = SYSCTL_ADD_NODE(ctx, par, OID_AUTO, "state", CTLFLAG_RD, NULL,
1715 	    "IOAT channel internal state");
1716 	state = SYSCTL_CHILDREN(tmp);
1717 
1718 	SYSCTL_ADD_UINT(ctx, state, OID_AUTO, "ring_size_order", CTLFLAG_RD,
1719 	    &ioat->ring_size_order, 0, "SW descriptor ring size order");
1720 	SYSCTL_ADD_UINT(ctx, state, OID_AUTO, "head", CTLFLAG_RD, &ioat->head,
1721 	    0, "SW descriptor head pointer index");
1722 	SYSCTL_ADD_UINT(ctx, state, OID_AUTO, "tail", CTLFLAG_RD, &ioat->tail,
1723 	    0, "SW descriptor tail pointer index");
1724 	SYSCTL_ADD_UINT(ctx, state, OID_AUTO, "hw_head", CTLFLAG_RD,
1725 	    &ioat->hw_head, 0, "HW DMACOUNT");
1726 
1727 	SYSCTL_ADD_UQUAD(ctx, state, OID_AUTO, "last_completion", CTLFLAG_RD,
1728 	    ioat->comp_update, "HW addr of last completion");
1729 
1730 	SYSCTL_ADD_INT(ctx, state, OID_AUTO, "is_resize_pending", CTLFLAG_RD,
1731 	    &ioat->is_resize_pending, 0, "resize pending");
1732 	SYSCTL_ADD_INT(ctx, state, OID_AUTO, "is_completion_pending",
1733 	    CTLFLAG_RD, &ioat->is_completion_pending, 0, "completion pending");
1734 	SYSCTL_ADD_INT(ctx, state, OID_AUTO, "is_reset_pending", CTLFLAG_RD,
1735 	    &ioat->is_reset_pending, 0, "reset pending");
1736 	SYSCTL_ADD_INT(ctx, state, OID_AUTO, "is_channel_running", CTLFLAG_RD,
1737 	    &ioat->is_channel_running, 0, "channel running");
1738 
1739 	SYSCTL_ADD_PROC(ctx, state, OID_AUTO, "chansts",
1740 	    CTLTYPE_STRING | CTLFLAG_RD, ioat, 0, sysctl_handle_chansts, "A",
1741 	    "String of the channel status");
1742 
1743 	SYSCTL_ADD_U16(ctx, state, OID_AUTO, "intrdelay", CTLFLAG_RD,
1744 	    &ioat->cached_intrdelay, 0,
1745 	    "Current INTRDELAY on this channel (cached, microseconds)");
1746 
1747 	tmp = SYSCTL_ADD_NODE(ctx, par, OID_AUTO, "hammer", CTLFLAG_RD, NULL,
1748 	    "Big hammers (mostly for testing)");
1749 	hammer = SYSCTL_CHILDREN(tmp);
1750 
1751 	SYSCTL_ADD_PROC(ctx, hammer, OID_AUTO, "force_hw_reset",
1752 	    CTLTYPE_INT | CTLFLAG_RW, ioat, 0, sysctl_handle_reset, "I",
1753 	    "Set to non-zero to reset the hardware");
1754 	SYSCTL_ADD_PROC(ctx, hammer, OID_AUTO, "force_hw_error",
1755 	    CTLTYPE_INT | CTLFLAG_RW, ioat, 0, sysctl_handle_error, "I",
1756 	    "Set to non-zero to inject a recoverable hardware error");
1757 
1758 	tmp = SYSCTL_ADD_NODE(ctx, par, OID_AUTO, "stats", CTLFLAG_RD, NULL,
1759 	    "IOAT channel statistics");
1760 	statpar = SYSCTL_CHILDREN(tmp);
1761 
1762 	SYSCTL_ADD_UQUAD(ctx, statpar, OID_AUTO, "interrupts", CTLFLAG_RW,
1763 	    &ioat->stats.interrupts,
1764 	    "Number of interrupts processed on this channel");
1765 	SYSCTL_ADD_UQUAD(ctx, statpar, OID_AUTO, "descriptors", CTLFLAG_RW,
1766 	    &ioat->stats.descriptors_processed,
1767 	    "Number of descriptors processed on this channel");
1768 	SYSCTL_ADD_UQUAD(ctx, statpar, OID_AUTO, "submitted", CTLFLAG_RW,
1769 	    &ioat->stats.descriptors_submitted,
1770 	    "Number of descriptors submitted to this channel");
1771 	SYSCTL_ADD_UQUAD(ctx, statpar, OID_AUTO, "errored", CTLFLAG_RW,
1772 	    &ioat->stats.descriptors_error,
1773 	    "Number of descriptors failed by channel errors");
1774 	SYSCTL_ADD_U32(ctx, statpar, OID_AUTO, "halts", CTLFLAG_RW,
1775 	    &ioat->stats.channel_halts, 0,
1776 	    "Number of times the channel has halted");
1777 	SYSCTL_ADD_U32(ctx, statpar, OID_AUTO, "last_halt_chanerr", CTLFLAG_RW,
1778 	    &ioat->stats.last_halt_chanerr, 0,
1779 	    "The raw CHANERR when the channel was last halted");
1780 
1781 	SYSCTL_ADD_PROC(ctx, statpar, OID_AUTO, "desc_per_interrupt",
1782 	    CTLTYPE_STRING | CTLFLAG_RD, ioat, 0, sysctl_handle_dpi, "A",
1783 	    "Descriptors per interrupt");
1784 }
1785 
1786 static inline struct ioat_softc *
1787 ioat_get(struct ioat_softc *ioat, enum ioat_ref_kind kind)
1788 {
1789 	uint32_t old;
1790 
1791 	KASSERT(kind < IOAT_NUM_REF_KINDS, ("bogus"));
1792 
1793 	old = atomic_fetchadd_32(&ioat->refcnt, 1);
1794 	KASSERT(old < UINT32_MAX, ("refcnt overflow"));
1795 
1796 #ifdef INVARIANTS
1797 	old = atomic_fetchadd_32(&ioat->refkinds[kind], 1);
1798 	KASSERT(old < UINT32_MAX, ("refcnt kind overflow"));
1799 #endif
1800 
1801 	return (ioat);
1802 }
1803 
1804 static inline void
1805 ioat_putn(struct ioat_softc *ioat, uint32_t n, enum ioat_ref_kind kind)
1806 {
1807 
1808 	_ioat_putn(ioat, n, kind, FALSE);
1809 }
1810 
1811 static inline void
1812 ioat_putn_locked(struct ioat_softc *ioat, uint32_t n, enum ioat_ref_kind kind)
1813 {
1814 
1815 	_ioat_putn(ioat, n, kind, TRUE);
1816 }
1817 
1818 static inline void
1819 _ioat_putn(struct ioat_softc *ioat, uint32_t n, enum ioat_ref_kind kind,
1820     boolean_t locked)
1821 {
1822 	uint32_t old;
1823 
1824 	KASSERT(kind < IOAT_NUM_REF_KINDS, ("bogus"));
1825 
1826 	if (n == 0)
1827 		return;
1828 
1829 #ifdef INVARIANTS
1830 	old = atomic_fetchadd_32(&ioat->refkinds[kind], -n);
1831 	KASSERT(old >= n, ("refcnt kind underflow"));
1832 #endif
1833 
1834 	/* Skip acquiring the lock if resulting refcnt > 0. */
1835 	for (;;) {
1836 		old = ioat->refcnt;
1837 		if (old <= n)
1838 			break;
1839 		if (atomic_cmpset_32(&ioat->refcnt, old, old - n))
1840 			return;
1841 	}
1842 
1843 	if (locked)
1844 		mtx_assert(IOAT_REFLK, MA_OWNED);
1845 	else
1846 		mtx_lock(IOAT_REFLK);
1847 
1848 	old = atomic_fetchadd_32(&ioat->refcnt, -n);
1849 	KASSERT(old >= n, ("refcnt error"));
1850 
1851 	if (old == n)
1852 		wakeup(IOAT_REFLK);
1853 	if (!locked)
1854 		mtx_unlock(IOAT_REFLK);
1855 }
1856 
1857 static inline void
1858 ioat_put(struct ioat_softc *ioat, enum ioat_ref_kind kind)
1859 {
1860 
1861 	ioat_putn(ioat, 1, kind);
1862 }
1863 
1864 static void
1865 ioat_drain_locked(struct ioat_softc *ioat)
1866 {
1867 
1868 	mtx_assert(IOAT_REFLK, MA_OWNED);
1869 	while (ioat->refcnt > 0)
1870 		msleep(IOAT_REFLK, IOAT_REFLK, 0, "ioat_drain", 0);
1871 }
1872