xref: /freebsd/sys/dev/ntb/ntb_transport.c (revision 0957b409)
1 /*-
2  * Copyright (c) 2016-2017 Alexander Motin <mav@FreeBSD.org>
3  * Copyright (C) 2013 Intel Corporation
4  * Copyright (C) 2015 EMC Corporation
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 AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * The Non-Transparent Bridge (NTB) is a device that allows you to connect
31  * two or more systems using a PCI-e links, providing remote memory access.
32  *
33  * This module contains a transport for sending and receiving messages by
34  * writing to remote memory window(s) provided by underlying NTB device.
35  *
36  * NOTE: Much of the code in this module is shared with Linux. Any patches may
37  * be picked up and redistributed in Linux with a dual GPL/BSD license.
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/param.h>
44 #include <sys/kernel.h>
45 #include <sys/systm.h>
46 #include <sys/bus.h>
47 #include <sys/ktr.h>
48 #include <sys/limits.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/module.h>
53 #include <sys/mutex.h>
54 #include <sys/queue.h>
55 #include <sys/sysctl.h>
56 #include <sys/taskqueue.h>
57 
58 #include <vm/vm.h>
59 #include <vm/pmap.h>
60 
61 #include <machine/bus.h>
62 
63 #include "ntb.h"
64 #include "ntb_transport.h"
65 
66 #define KTR_NTB KTR_SPARE3
67 
68 #define NTB_TRANSPORT_VERSION	4
69 
70 static SYSCTL_NODE(_hw, OID_AUTO, ntb_transport, CTLFLAG_RW, 0, "ntb_transport");
71 
72 static unsigned g_ntb_transport_debug_level;
73 SYSCTL_UINT(_hw_ntb_transport, OID_AUTO, debug_level, CTLFLAG_RWTUN,
74     &g_ntb_transport_debug_level, 0,
75     "ntb_transport log level -- higher is more verbose");
76 #define ntb_printf(lvl, ...) do {			\
77 	if ((lvl) <= g_ntb_transport_debug_level) {	\
78 		printf(__VA_ARGS__);			\
79 	}						\
80 } while (0)
81 
82 static unsigned transport_mtu = 0x10000;
83 
84 static uint64_t max_mw_size;
85 SYSCTL_UQUAD(_hw_ntb_transport, OID_AUTO, max_mw_size, CTLFLAG_RDTUN, &max_mw_size, 0,
86     "If enabled (non-zero), limit the size of large memory windows. "
87     "Both sides of the NTB MUST set the same value here.");
88 
89 static unsigned enable_xeon_watchdog;
90 SYSCTL_UINT(_hw_ntb_transport, OID_AUTO, enable_xeon_watchdog, CTLFLAG_RDTUN,
91     &enable_xeon_watchdog, 0, "If non-zero, write a register every second to "
92     "keep a watchdog from tearing down the NTB link");
93 
94 STAILQ_HEAD(ntb_queue_list, ntb_queue_entry);
95 
96 typedef uint32_t ntb_q_idx_t;
97 
98 struct ntb_queue_entry {
99 	/* ntb_queue list reference */
100 	STAILQ_ENTRY(ntb_queue_entry) entry;
101 
102 	/* info on data to be transferred */
103 	void		*cb_data;
104 	void		*buf;
105 	uint32_t	len;
106 	uint32_t	flags;
107 
108 	struct ntb_transport_qp		*qp;
109 	struct ntb_payload_header	*x_hdr;
110 	ntb_q_idx_t	index;
111 };
112 
113 struct ntb_rx_info {
114 	ntb_q_idx_t	entry;
115 };
116 
117 struct ntb_transport_qp {
118 	struct ntb_transport_ctx	*transport;
119 	device_t		 dev;
120 
121 	void			*cb_data;
122 
123 	bool			client_ready;
124 	volatile bool		link_is_up;
125 	uint8_t			qp_num;	/* Only 64 QPs are allowed.  0-63 */
126 
127 	struct ntb_rx_info	*rx_info;
128 	struct ntb_rx_info	*remote_rx_info;
129 
130 	void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
131 	    void *data, int len);
132 	struct ntb_queue_list	tx_free_q;
133 	struct mtx		ntb_tx_free_q_lock;
134 	caddr_t			tx_mw;
135 	bus_addr_t		tx_mw_phys;
136 	ntb_q_idx_t		tx_index;
137 	ntb_q_idx_t		tx_max_entry;
138 	uint64_t		tx_max_frame;
139 
140 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
141 	    void *data, int len);
142 	struct ntb_queue_list	rx_post_q;
143 	struct ntb_queue_list	rx_pend_q;
144 	/* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
145 	struct mtx		ntb_rx_q_lock;
146 	struct task		rxc_db_work;
147 	struct taskqueue	*rxc_tq;
148 	caddr_t			rx_buff;
149 	ntb_q_idx_t		rx_index;
150 	ntb_q_idx_t		rx_max_entry;
151 	uint64_t		rx_max_frame;
152 
153 	void (*event_handler)(void *data, enum ntb_link_event status);
154 	struct callout		link_work;
155 	struct callout		rx_full;
156 
157 	uint64_t		last_rx_no_buf;
158 
159 	/* Stats */
160 	uint64_t		rx_bytes;
161 	uint64_t		rx_pkts;
162 	uint64_t		rx_ring_empty;
163 	uint64_t		rx_err_no_buf;
164 	uint64_t		rx_err_oflow;
165 	uint64_t		rx_err_ver;
166 	uint64_t		tx_bytes;
167 	uint64_t		tx_pkts;
168 	uint64_t		tx_ring_full;
169 	uint64_t		tx_err_no_buf;
170 
171 	struct mtx		tx_lock;
172 };
173 
174 struct ntb_transport_mw {
175 	vm_paddr_t	phys_addr;
176 	size_t		phys_size;
177 	size_t		xlat_align;
178 	size_t		xlat_align_size;
179 	bus_addr_t	addr_limit;
180 	/* Tx buff is off vbase / phys_addr */
181 	caddr_t		vbase;
182 	size_t		xlat_size;
183 	size_t		buff_size;
184 	/* Rx buff is off virt_addr / dma_addr */
185 	bus_dma_tag_t	dma_tag;
186 	bus_dmamap_t	dma_map;
187 	caddr_t		virt_addr;
188 	bus_addr_t	dma_addr;
189 };
190 
191 struct ntb_transport_child {
192 	device_t	dev;
193 	int		consumer;
194 	int		qpoff;
195 	int		qpcnt;
196 	struct ntb_transport_child *next;
197 };
198 
199 struct ntb_transport_ctx {
200 	device_t		 dev;
201 	struct ntb_transport_child *child;
202 	struct ntb_transport_mw	*mw_vec;
203 	struct ntb_transport_qp	*qp_vec;
204 	unsigned		mw_count;
205 	unsigned		qp_count;
206 	uint64_t		qp_bitmap;
207 	volatile bool		link_is_up;
208 	enum ntb_speed		link_speed;
209 	enum ntb_width		link_width;
210 	struct callout		link_work;
211 	struct callout		link_watchdog;
212 	struct task		link_cleanup;
213 };
214 
215 enum {
216 	NTBT_DESC_DONE_FLAG = 1 << 0,
217 	NTBT_LINK_DOWN_FLAG = 1 << 1,
218 };
219 
220 struct ntb_payload_header {
221 	ntb_q_idx_t ver;
222 	uint32_t len;
223 	uint32_t flags;
224 };
225 
226 enum {
227 	/*
228 	 * The order of this enum is part of the remote protocol.  Do not
229 	 * reorder without bumping protocol version (and it's probably best
230 	 * to keep the protocol in lock-step with the Linux NTB driver.
231 	 */
232 	NTBT_VERSION = 0,
233 	NTBT_QP_LINKS,
234 	NTBT_NUM_QPS,
235 	NTBT_NUM_MWS,
236 	/*
237 	 * N.B.: transport_link_work assumes MW1 enums = MW0 + 2.
238 	 */
239 	NTBT_MW0_SZ_HIGH,
240 	NTBT_MW0_SZ_LOW,
241 	NTBT_MW1_SZ_HIGH,
242 	NTBT_MW1_SZ_LOW,
243 
244 	/*
245 	 * Some NTB-using hardware have a watchdog to work around NTB hangs; if
246 	 * a register or doorbell isn't written every few seconds, the link is
247 	 * torn down.  Write an otherwise unused register every few seconds to
248 	 * work around this watchdog.
249 	 */
250 	NTBT_WATCHDOG_SPAD = 15
251 };
252 
253 #define QP_TO_MW(nt, qp)	((qp) % nt->mw_count)
254 #define NTB_QP_DEF_NUM_ENTRIES	100
255 #define NTB_LINK_DOWN_TIMEOUT	100
256 
257 static int ntb_transport_probe(device_t dev);
258 static int ntb_transport_attach(device_t dev);
259 static int ntb_transport_detach(device_t dev);
260 static void ntb_transport_init_queue(struct ntb_transport_ctx *nt,
261     unsigned int qp_num);
262 static int ntb_process_tx(struct ntb_transport_qp *qp,
263     struct ntb_queue_entry *entry);
264 static void ntb_transport_rxc_db(void *arg, int pending);
265 static int ntb_process_rxc(struct ntb_transport_qp *qp);
266 static void ntb_memcpy_rx(struct ntb_transport_qp *qp,
267     struct ntb_queue_entry *entry, void *offset);
268 static inline void ntb_rx_copy_callback(struct ntb_transport_qp *qp,
269     void *data);
270 static void ntb_complete_rxc(struct ntb_transport_qp *qp);
271 static void ntb_transport_doorbell_callback(void *data, uint32_t vector);
272 static void ntb_transport_event_callback(void *data);
273 static void ntb_transport_link_work(void *arg);
274 static int ntb_set_mw(struct ntb_transport_ctx *, int num_mw, size_t size);
275 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw);
276 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
277     unsigned int qp_num);
278 static void ntb_qp_link_work(void *arg);
279 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt);
280 static void ntb_transport_link_cleanup_work(void *, int);
281 static void ntb_qp_link_down(struct ntb_transport_qp *qp);
282 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp);
283 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp);
284 static void ntb_send_link_down(struct ntb_transport_qp *qp);
285 static void ntb_list_add(struct mtx *lock, struct ntb_queue_entry *entry,
286     struct ntb_queue_list *list);
287 static struct ntb_queue_entry *ntb_list_rm(struct mtx *lock,
288     struct ntb_queue_list *list);
289 static struct ntb_queue_entry *ntb_list_mv(struct mtx *lock,
290     struct ntb_queue_list *from, struct ntb_queue_list *to);
291 static void xeon_link_watchdog_hb(void *);
292 
293 static const struct ntb_ctx_ops ntb_transport_ops = {
294 	.link_event = ntb_transport_event_callback,
295 	.db_event = ntb_transport_doorbell_callback,
296 };
297 
298 MALLOC_DEFINE(M_NTB_T, "ntb_transport", "ntb transport driver");
299 
300 static inline void
301 iowrite32(uint32_t val, void *addr)
302 {
303 
304 	bus_space_write_4(X86_BUS_SPACE_MEM, 0/* HACK */, (uintptr_t)addr,
305 	    val);
306 }
307 
308 /* Transport Init and teardown */
309 
310 static void
311 xeon_link_watchdog_hb(void *arg)
312 {
313 	struct ntb_transport_ctx *nt;
314 
315 	nt = arg;
316 	ntb_spad_write(nt->dev, NTBT_WATCHDOG_SPAD, 0);
317 	callout_reset(&nt->link_watchdog, 1 * hz, xeon_link_watchdog_hb, nt);
318 }
319 
320 static int
321 ntb_transport_probe(device_t dev)
322 {
323 
324 	device_set_desc(dev, "NTB Transport");
325 	return (0);
326 }
327 
328 static int
329 ntb_transport_attach(device_t dev)
330 {
331 	struct ntb_transport_ctx *nt = device_get_softc(dev);
332 	struct ntb_transport_child **cpp = &nt->child;
333 	struct ntb_transport_child *nc;
334 	struct ntb_transport_mw *mw;
335 	uint64_t db_bitmap, size;
336 	int rc, i, db_count, spad_count, qp, qpu, qpo, qpt;
337 	char cfg[128] = "";
338 	char buf[32];
339 	char *n, *np, *c, *name;
340 
341 	nt->dev = dev;
342 	nt->mw_count = ntb_mw_count(dev);
343 	spad_count = ntb_spad_count(dev);
344 	db_bitmap = ntb_db_valid_mask(dev);
345 	db_count = flsll(db_bitmap);
346 	KASSERT(db_bitmap == (1 << db_count) - 1,
347 	    ("Doorbells are not sequential (%jx).\n", db_bitmap));
348 
349 	if (nt->mw_count == 0) {
350 		device_printf(dev, "At least 1 memory window required.\n");
351 		return (ENXIO);
352 	}
353 	if (spad_count < 6) {
354 		device_printf(dev, "At least 6 scratchpads required.\n");
355 		return (ENXIO);
356 	}
357 	if (spad_count < 4 + 2 * nt->mw_count) {
358 		nt->mw_count = (spad_count - 4) / 2;
359 		device_printf(dev, "Scratchpads enough only for %d "
360 		    "memory windows.\n", nt->mw_count);
361 	}
362 	if (db_bitmap == 0) {
363 		device_printf(dev, "At least one doorbell required.\n");
364 		return (ENXIO);
365 	}
366 
367 	nt->mw_vec = malloc(nt->mw_count * sizeof(*nt->mw_vec), M_NTB_T,
368 	    M_WAITOK | M_ZERO);
369 	for (i = 0; i < nt->mw_count; i++) {
370 		mw = &nt->mw_vec[i];
371 
372 		rc = ntb_mw_get_range(dev, i, &mw->phys_addr, &mw->vbase,
373 		    &mw->phys_size, &mw->xlat_align, &mw->xlat_align_size,
374 		    &mw->addr_limit);
375 		if (rc != 0)
376 			goto err;
377 
378 		mw->buff_size = 0;
379 		mw->xlat_size = 0;
380 		mw->virt_addr = NULL;
381 		mw->dma_addr = 0;
382 
383 		rc = ntb_mw_set_wc(dev, i, VM_MEMATTR_WRITE_COMBINING);
384 		if (rc)
385 			ntb_printf(0, "Unable to set mw%d caching\n", i);
386 
387 		/*
388 		 * Try to preallocate receive memory early, since there may
389 		 * be not enough contiguous memory later.  It is quite likely
390 		 * that NTB windows are symmetric and this allocation remain,
391 		 * but even if not, we will just reallocate it later.
392 		 */
393 		size = mw->phys_size;
394 		if (max_mw_size != 0 && size > max_mw_size)
395 			size = max_mw_size;
396 		ntb_set_mw(nt, i, size);
397 	}
398 
399 	qpu = 0;
400 	qpo = imin(db_count, nt->mw_count);
401 	qpt = db_count;
402 
403 	snprintf(buf, sizeof(buf), "hint.%s.%d.config", device_get_name(dev),
404 	    device_get_unit(dev));
405 	TUNABLE_STR_FETCH(buf, cfg, sizeof(cfg));
406 	n = cfg;
407 	i = 0;
408 	while ((c = strsep(&n, ",")) != NULL) {
409 		np = c;
410 		name = strsep(&np, ":");
411 		if (name != NULL && name[0] == 0)
412 			name = NULL;
413 		qp = (np && np[0] != 0) ? strtol(np, NULL, 10) : qpo - qpu;
414 		if (qp <= 0)
415 			qp = 1;
416 
417 		if (qp > qpt - qpu) {
418 			device_printf(dev, "Not enough resources for config\n");
419 			break;
420 		}
421 
422 		nc = malloc(sizeof(*nc), M_DEVBUF, M_WAITOK | M_ZERO);
423 		nc->consumer = i;
424 		nc->qpoff = qpu;
425 		nc->qpcnt = qp;
426 		nc->dev = device_add_child(dev, name, -1);
427 		if (nc->dev == NULL) {
428 			device_printf(dev, "Can not add child.\n");
429 			break;
430 		}
431 		device_set_ivars(nc->dev, nc);
432 		*cpp = nc;
433 		cpp = &nc->next;
434 
435 		if (bootverbose) {
436 			device_printf(dev, "%d \"%s\": queues %d",
437 			    i, name, qpu);
438 			if (qp > 1)
439 				printf("-%d", qpu + qp - 1);
440 			printf("\n");
441 		}
442 
443 		qpu += qp;
444 		i++;
445 	}
446 	nt->qp_count = qpu;
447 
448 	nt->qp_vec = malloc(nt->qp_count * sizeof(*nt->qp_vec), M_NTB_T,
449 	    M_WAITOK | M_ZERO);
450 
451 	for (i = 0; i < nt->qp_count; i++)
452 		ntb_transport_init_queue(nt, i);
453 
454 	callout_init(&nt->link_work, 0);
455 	callout_init(&nt->link_watchdog, 0);
456 	TASK_INIT(&nt->link_cleanup, 0, ntb_transport_link_cleanup_work, nt);
457 	nt->link_is_up = false;
458 
459 	rc = ntb_set_ctx(dev, nt, &ntb_transport_ops);
460 	if (rc != 0)
461 		goto err;
462 
463 	ntb_link_enable(dev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
464 
465 	if (enable_xeon_watchdog != 0)
466 		callout_reset(&nt->link_watchdog, 0, xeon_link_watchdog_hb, nt);
467 
468 	bus_generic_attach(dev);
469 	return (0);
470 
471 err:
472 	free(nt->qp_vec, M_NTB_T);
473 	free(nt->mw_vec, M_NTB_T);
474 	return (rc);
475 }
476 
477 static int
478 ntb_transport_detach(device_t dev)
479 {
480 	struct ntb_transport_ctx *nt = device_get_softc(dev);
481 	struct ntb_transport_child **cpp = &nt->child;
482 	struct ntb_transport_child *nc;
483 	int error = 0, i;
484 
485 	while ((nc = *cpp) != NULL) {
486 		*cpp = (*cpp)->next;
487 		error = device_delete_child(dev, nc->dev);
488 		if (error)
489 			break;
490 		free(nc, M_DEVBUF);
491 	}
492 	KASSERT(nt->qp_bitmap == 0,
493 	    ("Some queues not freed on detach (%jx)", nt->qp_bitmap));
494 
495 	ntb_transport_link_cleanup(nt);
496 	taskqueue_drain(taskqueue_swi, &nt->link_cleanup);
497 	callout_drain(&nt->link_work);
498 	callout_drain(&nt->link_watchdog);
499 
500 	ntb_link_disable(dev);
501 	ntb_clear_ctx(dev);
502 
503 	for (i = 0; i < nt->mw_count; i++)
504 		ntb_free_mw(nt, i);
505 
506 	free(nt->qp_vec, M_NTB_T);
507 	free(nt->mw_vec, M_NTB_T);
508 	return (0);
509 }
510 
511 static int
512 ntb_transport_print_child(device_t dev, device_t child)
513 {
514 	struct ntb_transport_child *nc = device_get_ivars(child);
515 	int retval;
516 
517 	retval = bus_print_child_header(dev, child);
518 	if (nc->qpcnt > 0) {
519 		printf(" queue %d", nc->qpoff);
520 		if (nc->qpcnt > 1)
521 			printf("-%d", nc->qpoff + nc->qpcnt - 1);
522 	}
523 	retval += printf(" at consumer %d", nc->consumer);
524 	retval += bus_print_child_domain(dev, child);
525 	retval += bus_print_child_footer(dev, child);
526 
527 	return (retval);
528 }
529 
530 static int
531 ntb_transport_child_location_str(device_t dev, device_t child, char *buf,
532     size_t buflen)
533 {
534 	struct ntb_transport_child *nc = device_get_ivars(child);
535 
536 	snprintf(buf, buflen, "consumer=%d", nc->consumer);
537 	return (0);
538 }
539 
540 int
541 ntb_transport_queue_count(device_t dev)
542 {
543 	struct ntb_transport_child *nc = device_get_ivars(dev);
544 
545 	return (nc->qpcnt);
546 }
547 
548 static void
549 ntb_transport_init_queue(struct ntb_transport_ctx *nt, unsigned int qp_num)
550 {
551 	struct ntb_transport_mw *mw;
552 	struct ntb_transport_qp *qp;
553 	vm_paddr_t mw_base;
554 	uint64_t mw_size, qp_offset;
555 	size_t tx_size;
556 	unsigned num_qps_mw, mw_num, mw_count;
557 
558 	mw_count = nt->mw_count;
559 	mw_num = QP_TO_MW(nt, qp_num);
560 	mw = &nt->mw_vec[mw_num];
561 
562 	qp = &nt->qp_vec[qp_num];
563 	qp->qp_num = qp_num;
564 	qp->transport = nt;
565 	qp->dev = nt->dev;
566 	qp->client_ready = false;
567 	qp->event_handler = NULL;
568 	ntb_qp_link_down_reset(qp);
569 
570 	if (mw_num < nt->qp_count % mw_count)
571 		num_qps_mw = nt->qp_count / mw_count + 1;
572 	else
573 		num_qps_mw = nt->qp_count / mw_count;
574 
575 	mw_base = mw->phys_addr;
576 	mw_size = mw->phys_size;
577 
578 	tx_size = mw_size / num_qps_mw;
579 	qp_offset = tx_size * (qp_num / mw_count);
580 
581 	qp->tx_mw = mw->vbase + qp_offset;
582 	KASSERT(qp->tx_mw != NULL, ("uh oh?"));
583 
584 	/* XXX Assumes that a vm_paddr_t is equivalent to bus_addr_t */
585 	qp->tx_mw_phys = mw_base + qp_offset;
586 	KASSERT(qp->tx_mw_phys != 0, ("uh oh?"));
587 
588 	tx_size -= sizeof(struct ntb_rx_info);
589 	qp->rx_info = (void *)(qp->tx_mw + tx_size);
590 
591 	/* Due to house-keeping, there must be at least 2 buffs */
592 	qp->tx_max_frame = qmin(transport_mtu, tx_size / 2);
593 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
594 
595 	callout_init(&qp->link_work, 0);
596 	callout_init(&qp->rx_full, 1);
597 
598 	mtx_init(&qp->ntb_rx_q_lock, "ntb rx q", NULL, MTX_SPIN);
599 	mtx_init(&qp->ntb_tx_free_q_lock, "ntb tx free q", NULL, MTX_SPIN);
600 	mtx_init(&qp->tx_lock, "ntb transport tx", NULL, MTX_DEF);
601 	TASK_INIT(&qp->rxc_db_work, 0, ntb_transport_rxc_db, qp);
602 	qp->rxc_tq = taskqueue_create("ntbt_rx", M_WAITOK,
603 	    taskqueue_thread_enqueue, &qp->rxc_tq);
604 	taskqueue_start_threads(&qp->rxc_tq, 1, PI_NET, "%s rx%d",
605 	    device_get_nameunit(nt->dev), qp_num);
606 
607 	STAILQ_INIT(&qp->rx_post_q);
608 	STAILQ_INIT(&qp->rx_pend_q);
609 	STAILQ_INIT(&qp->tx_free_q);
610 }
611 
612 void
613 ntb_transport_free_queue(struct ntb_transport_qp *qp)
614 {
615 	struct ntb_transport_ctx *nt = qp->transport;
616 	struct ntb_queue_entry *entry;
617 
618 	callout_drain(&qp->link_work);
619 
620 	ntb_db_set_mask(qp->dev, 1ull << qp->qp_num);
621 	taskqueue_drain_all(qp->rxc_tq);
622 	taskqueue_free(qp->rxc_tq);
623 
624 	qp->cb_data = NULL;
625 	qp->rx_handler = NULL;
626 	qp->tx_handler = NULL;
627 	qp->event_handler = NULL;
628 
629 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q)))
630 		free(entry, M_NTB_T);
631 
632 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q)))
633 		free(entry, M_NTB_T);
634 
635 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
636 		free(entry, M_NTB_T);
637 
638 	nt->qp_bitmap &= ~(1 << qp->qp_num);
639 }
640 
641 /**
642  * ntb_transport_create_queue - Create a new NTB transport layer queue
643  * @rx_handler: receive callback function
644  * @tx_handler: transmit callback function
645  * @event_handler: event callback function
646  *
647  * Create a new NTB transport layer queue and provide the queue with a callback
648  * routine for both transmit and receive.  The receive callback routine will be
649  * used to pass up data when the transport has received it on the queue.   The
650  * transmit callback routine will be called when the transport has completed the
651  * transmission of the data on the queue and the data is ready to be freed.
652  *
653  * RETURNS: pointer to newly created ntb_queue, NULL on error.
654  */
655 struct ntb_transport_qp *
656 ntb_transport_create_queue(device_t dev, int q,
657     const struct ntb_queue_handlers *handlers, void *data)
658 {
659 	struct ntb_transport_child *nc = device_get_ivars(dev);
660 	struct ntb_transport_ctx *nt = device_get_softc(device_get_parent(dev));
661 	struct ntb_queue_entry *entry;
662 	struct ntb_transport_qp *qp;
663 	int i;
664 
665 	if (q < 0 || q >= nc->qpcnt)
666 		return (NULL);
667 
668 	qp = &nt->qp_vec[nc->qpoff + q];
669 	nt->qp_bitmap |= (1 << qp->qp_num);
670 	qp->cb_data = data;
671 	qp->rx_handler = handlers->rx_handler;
672 	qp->tx_handler = handlers->tx_handler;
673 	qp->event_handler = handlers->event_handler;
674 
675 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
676 		entry = malloc(sizeof(*entry), M_NTB_T, M_WAITOK | M_ZERO);
677 		entry->cb_data = data;
678 		entry->buf = NULL;
679 		entry->len = transport_mtu;
680 		entry->qp = qp;
681 		ntb_list_add(&qp->ntb_rx_q_lock, entry, &qp->rx_pend_q);
682 	}
683 
684 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
685 		entry = malloc(sizeof(*entry), M_NTB_T, M_WAITOK | M_ZERO);
686 		entry->qp = qp;
687 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
688 	}
689 
690 	ntb_db_clear(dev, 1ull << qp->qp_num);
691 	return (qp);
692 }
693 
694 /**
695  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
696  * @qp: NTB transport layer queue to be enabled
697  *
698  * Notify NTB transport layer of client readiness to use queue
699  */
700 void
701 ntb_transport_link_up(struct ntb_transport_qp *qp)
702 {
703 	struct ntb_transport_ctx *nt = qp->transport;
704 
705 	qp->client_ready = true;
706 
707 	ntb_printf(2, "qp %d client ready\n", qp->qp_num);
708 
709 	if (nt->link_is_up)
710 		callout_reset(&qp->link_work, 0, ntb_qp_link_work, qp);
711 }
712 
713 
714 
715 /* Transport Tx */
716 
717 /**
718  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
719  * @qp: NTB transport layer queue the entry is to be enqueued on
720  * @cb: per buffer pointer for callback function to use
721  * @data: pointer to data buffer that will be sent
722  * @len: length of the data buffer
723  *
724  * Enqueue a new transmit buffer onto the transport queue from which a NTB
725  * payload will be transmitted.  This assumes that a lock is being held to
726  * serialize access to the qp.
727  *
728  * RETURNS: An appropriate ERRNO error value on error, or zero for success.
729  */
730 int
731 ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
732     unsigned int len)
733 {
734 	struct ntb_queue_entry *entry;
735 	int rc;
736 
737 	if (!qp->link_is_up || len == 0) {
738 		CTR0(KTR_NTB, "TX: link not up");
739 		return (EINVAL);
740 	}
741 
742 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
743 	if (entry == NULL) {
744 		CTR0(KTR_NTB, "TX: could not get entry from tx_free_q");
745 		qp->tx_err_no_buf++;
746 		return (EBUSY);
747 	}
748 	CTR1(KTR_NTB, "TX: got entry %p from tx_free_q", entry);
749 
750 	entry->cb_data = cb;
751 	entry->buf = data;
752 	entry->len = len;
753 	entry->flags = 0;
754 
755 	mtx_lock(&qp->tx_lock);
756 	rc = ntb_process_tx(qp, entry);
757 	mtx_unlock(&qp->tx_lock);
758 	if (rc != 0) {
759 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
760 		CTR1(KTR_NTB,
761 		    "TX: process_tx failed. Returning entry %p to tx_free_q",
762 		    entry);
763 	}
764 	return (rc);
765 }
766 
767 static void
768 ntb_tx_copy_callback(void *data)
769 {
770 	struct ntb_queue_entry *entry = data;
771 	struct ntb_transport_qp *qp = entry->qp;
772 	struct ntb_payload_header *hdr = entry->x_hdr;
773 
774 	iowrite32(entry->flags | NTBT_DESC_DONE_FLAG, &hdr->flags);
775 	CTR1(KTR_NTB, "TX: hdr %p set DESC_DONE", hdr);
776 
777 	ntb_peer_db_set(qp->dev, 1ull << qp->qp_num);
778 
779 	/*
780 	 * The entry length can only be zero if the packet is intended to be a
781 	 * "link down" or similar.  Since no payload is being sent in these
782 	 * cases, there is nothing to add to the completion queue.
783 	 */
784 	if (entry->len > 0) {
785 		qp->tx_bytes += entry->len;
786 
787 		if (qp->tx_handler)
788 			qp->tx_handler(qp, qp->cb_data, entry->buf,
789 			    entry->len);
790 		else
791 			m_freem(entry->buf);
792 		entry->buf = NULL;
793 	}
794 
795 	CTR3(KTR_NTB,
796 	    "TX: entry %p sent. hdr->ver = %u, hdr->flags = 0x%x, Returning "
797 	    "to tx_free_q", entry, hdr->ver, hdr->flags);
798 	ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
799 }
800 
801 static void
802 ntb_memcpy_tx(struct ntb_queue_entry *entry, void *offset)
803 {
804 
805 	CTR2(KTR_NTB, "TX: copying %d bytes to offset %p", entry->len, offset);
806 	if (entry->buf != NULL) {
807 		m_copydata((struct mbuf *)entry->buf, 0, entry->len, offset);
808 
809 		/*
810 		 * Ensure that the data is fully copied before setting the
811 		 * flags
812 		 */
813 		wmb();
814 	}
815 
816 	ntb_tx_copy_callback(entry);
817 }
818 
819 static void
820 ntb_async_tx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry)
821 {
822 	struct ntb_payload_header *hdr;
823 	void *offset;
824 
825 	offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
826 	hdr = (struct ntb_payload_header *)((char *)offset + qp->tx_max_frame -
827 	    sizeof(struct ntb_payload_header));
828 	entry->x_hdr = hdr;
829 
830 	iowrite32(entry->len, &hdr->len);
831 	iowrite32(qp->tx_pkts, &hdr->ver);
832 
833 	ntb_memcpy_tx(entry, offset);
834 }
835 
836 static int
837 ntb_process_tx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry)
838 {
839 
840 	CTR3(KTR_NTB,
841 	    "TX: process_tx: tx_pkts=%lu, tx_index=%u, remote entry=%u",
842 	    qp->tx_pkts, qp->tx_index, qp->remote_rx_info->entry);
843 	if (qp->tx_index == qp->remote_rx_info->entry) {
844 		CTR0(KTR_NTB, "TX: ring full");
845 		qp->tx_ring_full++;
846 		return (EAGAIN);
847 	}
848 
849 	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
850 		if (qp->tx_handler != NULL)
851 			qp->tx_handler(qp, qp->cb_data, entry->buf,
852 			    EIO);
853 		else
854 			m_freem(entry->buf);
855 
856 		entry->buf = NULL;
857 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
858 		CTR1(KTR_NTB,
859 		    "TX: frame too big. returning entry %p to tx_free_q",
860 		    entry);
861 		return (0);
862 	}
863 	CTR2(KTR_NTB, "TX: copying entry %p to index %u", entry, qp->tx_index);
864 	ntb_async_tx(qp, entry);
865 
866 	qp->tx_index++;
867 	qp->tx_index %= qp->tx_max_entry;
868 
869 	qp->tx_pkts++;
870 
871 	return (0);
872 }
873 
874 /* Transport Rx */
875 static void
876 ntb_transport_rxc_db(void *arg, int pending __unused)
877 {
878 	struct ntb_transport_qp *qp = arg;
879 	uint64_t qp_mask = 1ull << qp->qp_num;
880 	int rc;
881 
882 	CTR0(KTR_NTB, "RX: transport_rx");
883 again:
884 	while ((rc = ntb_process_rxc(qp)) == 0)
885 		;
886 	CTR1(KTR_NTB, "RX: process_rxc returned %d", rc);
887 
888 	if ((ntb_db_read(qp->dev) & qp_mask) != 0) {
889 		/* If db is set, clear it and check queue once more. */
890 		ntb_db_clear(qp->dev, qp_mask);
891 		goto again;
892 	}
893 	if (qp->link_is_up)
894 		ntb_db_clear_mask(qp->dev, qp_mask);
895 }
896 
897 static int
898 ntb_process_rxc(struct ntb_transport_qp *qp)
899 {
900 	struct ntb_payload_header *hdr;
901 	struct ntb_queue_entry *entry;
902 	caddr_t offset;
903 
904 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
905 	hdr = (void *)(offset + qp->rx_max_frame -
906 	    sizeof(struct ntb_payload_header));
907 
908 	CTR1(KTR_NTB, "RX: process_rxc rx_index = %u", qp->rx_index);
909 	if ((hdr->flags & NTBT_DESC_DONE_FLAG) == 0) {
910 		CTR0(KTR_NTB, "RX: hdr not done");
911 		qp->rx_ring_empty++;
912 		return (EAGAIN);
913 	}
914 
915 	if ((hdr->flags & NTBT_LINK_DOWN_FLAG) != 0) {
916 		CTR0(KTR_NTB, "RX: link down");
917 		ntb_qp_link_down(qp);
918 		hdr->flags = 0;
919 		return (EAGAIN);
920 	}
921 
922 	if (hdr->ver != (uint32_t)qp->rx_pkts) {
923 		CTR2(KTR_NTB,"RX: ver != rx_pkts (%x != %lx). "
924 		    "Returning entry to rx_pend_q", hdr->ver, qp->rx_pkts);
925 		qp->rx_err_ver++;
926 		return (EIO);
927 	}
928 
929 	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
930 	if (entry == NULL) {
931 		qp->rx_err_no_buf++;
932 		CTR0(KTR_NTB, "RX: No entries in rx_pend_q");
933 		return (EAGAIN);
934 	}
935 	callout_stop(&qp->rx_full);
936 	CTR1(KTR_NTB, "RX: rx entry %p from rx_pend_q", entry);
937 
938 	entry->x_hdr = hdr;
939 	entry->index = qp->rx_index;
940 
941 	if (hdr->len > entry->len) {
942 		CTR2(KTR_NTB, "RX: len too long. Wanted %ju got %ju",
943 		    (uintmax_t)hdr->len, (uintmax_t)entry->len);
944 		qp->rx_err_oflow++;
945 
946 		entry->len = -EIO;
947 		entry->flags |= NTBT_DESC_DONE_FLAG;
948 
949 		ntb_complete_rxc(qp);
950 	} else {
951 		qp->rx_bytes += hdr->len;
952 		qp->rx_pkts++;
953 
954 		CTR1(KTR_NTB, "RX: received %ld rx_pkts", qp->rx_pkts);
955 
956 		entry->len = hdr->len;
957 
958 		ntb_memcpy_rx(qp, entry, offset);
959 	}
960 
961 	qp->rx_index++;
962 	qp->rx_index %= qp->rx_max_entry;
963 	return (0);
964 }
965 
966 static void
967 ntb_memcpy_rx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry,
968     void *offset)
969 {
970 	struct ifnet *ifp = entry->cb_data;
971 	unsigned int len = entry->len;
972 
973 	CTR2(KTR_NTB, "RX: copying %d bytes from offset %p", len, offset);
974 
975 	entry->buf = (void *)m_devget(offset, len, 0, ifp, NULL);
976 	if (entry->buf == NULL)
977 		entry->len = -ENOMEM;
978 
979 	/* Ensure that the data is globally visible before clearing the flag */
980 	wmb();
981 
982 	CTR2(KTR_NTB, "RX: copied entry %p to mbuf %p.", entry, entry->buf);
983 	ntb_rx_copy_callback(qp, entry);
984 }
985 
986 static inline void
987 ntb_rx_copy_callback(struct ntb_transport_qp *qp, void *data)
988 {
989 	struct ntb_queue_entry *entry;
990 
991 	entry = data;
992 	entry->flags |= NTBT_DESC_DONE_FLAG;
993 	ntb_complete_rxc(qp);
994 }
995 
996 static void
997 ntb_complete_rxc(struct ntb_transport_qp *qp)
998 {
999 	struct ntb_queue_entry *entry;
1000 	struct mbuf *m;
1001 	unsigned len;
1002 
1003 	CTR0(KTR_NTB, "RX: rx_completion_task");
1004 
1005 	mtx_lock_spin(&qp->ntb_rx_q_lock);
1006 
1007 	while (!STAILQ_EMPTY(&qp->rx_post_q)) {
1008 		entry = STAILQ_FIRST(&qp->rx_post_q);
1009 		if ((entry->flags & NTBT_DESC_DONE_FLAG) == 0)
1010 			break;
1011 
1012 		entry->x_hdr->flags = 0;
1013 		iowrite32(entry->index, &qp->rx_info->entry);
1014 
1015 		STAILQ_REMOVE_HEAD(&qp->rx_post_q, entry);
1016 
1017 		len = entry->len;
1018 		m = entry->buf;
1019 
1020 		/*
1021 		 * Re-initialize queue_entry for reuse; rx_handler takes
1022 		 * ownership of the mbuf.
1023 		 */
1024 		entry->buf = NULL;
1025 		entry->len = transport_mtu;
1026 		entry->cb_data = qp->cb_data;
1027 
1028 		STAILQ_INSERT_TAIL(&qp->rx_pend_q, entry, entry);
1029 
1030 		mtx_unlock_spin(&qp->ntb_rx_q_lock);
1031 
1032 		CTR2(KTR_NTB, "RX: completing entry %p, mbuf %p", entry, m);
1033 		if (qp->rx_handler != NULL && qp->client_ready)
1034 			qp->rx_handler(qp, qp->cb_data, m, len);
1035 		else
1036 			m_freem(m);
1037 
1038 		mtx_lock_spin(&qp->ntb_rx_q_lock);
1039 	}
1040 
1041 	mtx_unlock_spin(&qp->ntb_rx_q_lock);
1042 }
1043 
1044 static void
1045 ntb_transport_doorbell_callback(void *data, uint32_t vector)
1046 {
1047 	struct ntb_transport_ctx *nt = data;
1048 	struct ntb_transport_qp *qp;
1049 	uint64_t vec_mask;
1050 	unsigned qp_num;
1051 
1052 	vec_mask = ntb_db_vector_mask(nt->dev, vector);
1053 	vec_mask &= nt->qp_bitmap;
1054 	if ((vec_mask & (vec_mask - 1)) != 0)
1055 		vec_mask &= ntb_db_read(nt->dev);
1056 	if (vec_mask != 0) {
1057 		ntb_db_set_mask(nt->dev, vec_mask);
1058 		ntb_db_clear(nt->dev, vec_mask);
1059 	}
1060 	while (vec_mask != 0) {
1061 		qp_num = ffsll(vec_mask) - 1;
1062 
1063 		qp = &nt->qp_vec[qp_num];
1064 		if (qp->link_is_up)
1065 			taskqueue_enqueue(qp->rxc_tq, &qp->rxc_db_work);
1066 
1067 		vec_mask &= ~(1ull << qp_num);
1068 	}
1069 }
1070 
1071 /* Link Event handler */
1072 static void
1073 ntb_transport_event_callback(void *data)
1074 {
1075 	struct ntb_transport_ctx *nt = data;
1076 
1077 	if (ntb_link_is_up(nt->dev, &nt->link_speed, &nt->link_width)) {
1078 		ntb_printf(1, "HW link up\n");
1079 		callout_reset(&nt->link_work, 0, ntb_transport_link_work, nt);
1080 	} else {
1081 		ntb_printf(1, "HW link down\n");
1082 		taskqueue_enqueue(taskqueue_swi, &nt->link_cleanup);
1083 	}
1084 }
1085 
1086 /* Link bring up */
1087 static void
1088 ntb_transport_link_work(void *arg)
1089 {
1090 	struct ntb_transport_ctx *nt = arg;
1091 	device_t dev = nt->dev;
1092 	struct ntb_transport_qp *qp;
1093 	uint64_t val64, size;
1094 	uint32_t val;
1095 	unsigned i;
1096 	int rc;
1097 
1098 	/* send the local info, in the opposite order of the way we read it */
1099 	for (i = 0; i < nt->mw_count; i++) {
1100 		size = nt->mw_vec[i].phys_size;
1101 
1102 		if (max_mw_size != 0 && size > max_mw_size)
1103 			size = max_mw_size;
1104 
1105 		ntb_peer_spad_write(dev, NTBT_MW0_SZ_HIGH + (i * 2),
1106 		    size >> 32);
1107 		ntb_peer_spad_write(dev, NTBT_MW0_SZ_LOW + (i * 2), size);
1108 	}
1109 	ntb_peer_spad_write(dev, NTBT_NUM_MWS, nt->mw_count);
1110 	ntb_peer_spad_write(dev, NTBT_NUM_QPS, nt->qp_count);
1111 	ntb_peer_spad_write(dev, NTBT_QP_LINKS, 0);
1112 	ntb_peer_spad_write(dev, NTBT_VERSION, NTB_TRANSPORT_VERSION);
1113 
1114 	/* Query the remote side for its info */
1115 	val = 0;
1116 	ntb_spad_read(dev, NTBT_VERSION, &val);
1117 	if (val != NTB_TRANSPORT_VERSION)
1118 		goto out;
1119 
1120 	ntb_spad_read(dev, NTBT_NUM_QPS, &val);
1121 	if (val != nt->qp_count)
1122 		goto out;
1123 
1124 	ntb_spad_read(dev, NTBT_NUM_MWS, &val);
1125 	if (val != nt->mw_count)
1126 		goto out;
1127 
1128 	for (i = 0; i < nt->mw_count; i++) {
1129 		ntb_spad_read(dev, NTBT_MW0_SZ_HIGH + (i * 2), &val);
1130 		val64 = (uint64_t)val << 32;
1131 
1132 		ntb_spad_read(dev, NTBT_MW0_SZ_LOW + (i * 2), &val);
1133 		val64 |= val;
1134 
1135 		rc = ntb_set_mw(nt, i, val64);
1136 		if (rc != 0)
1137 			goto free_mws;
1138 	}
1139 
1140 	nt->link_is_up = true;
1141 	ntb_printf(1, "transport link up\n");
1142 
1143 	for (i = 0; i < nt->qp_count; i++) {
1144 		qp = &nt->qp_vec[i];
1145 
1146 		ntb_transport_setup_qp_mw(nt, i);
1147 
1148 		if (qp->client_ready)
1149 			callout_reset(&qp->link_work, 0, ntb_qp_link_work, qp);
1150 	}
1151 
1152 	return;
1153 
1154 free_mws:
1155 	for (i = 0; i < nt->mw_count; i++)
1156 		ntb_free_mw(nt, i);
1157 out:
1158 	if (ntb_link_is_up(dev, &nt->link_speed, &nt->link_width))
1159 		callout_reset(&nt->link_work,
1160 		    NTB_LINK_DOWN_TIMEOUT * hz / 1000, ntb_transport_link_work, nt);
1161 }
1162 
1163 struct ntb_load_cb_args {
1164 	bus_addr_t addr;
1165 	int error;
1166 };
1167 
1168 static void
1169 ntb_load_cb(void *xsc, bus_dma_segment_t *segs, int nsegs, int error)
1170 {
1171 	struct ntb_load_cb_args *cba = (struct ntb_load_cb_args *)xsc;
1172 
1173 	if (!(cba->error = error))
1174 		cba->addr = segs[0].ds_addr;
1175 }
1176 
1177 static int
1178 ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw, size_t size)
1179 {
1180 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
1181 	struct ntb_load_cb_args cba;
1182 	size_t xlat_size, buff_size;
1183 	int rc;
1184 
1185 	if (size == 0)
1186 		return (EINVAL);
1187 
1188 	xlat_size = roundup(size, mw->xlat_align_size);
1189 	buff_size = xlat_size;
1190 
1191 	/* No need to re-setup */
1192 	if (mw->xlat_size == xlat_size)
1193 		return (0);
1194 
1195 	if (mw->buff_size != 0)
1196 		ntb_free_mw(nt, num_mw);
1197 
1198 	/* Alloc memory for receiving data.  Must be aligned */
1199 	mw->xlat_size = xlat_size;
1200 	mw->buff_size = buff_size;
1201 
1202 	if (bus_dma_tag_create(bus_get_dma_tag(nt->dev), mw->xlat_align, 0,
1203 	    mw->addr_limit, BUS_SPACE_MAXADDR,
1204 	    NULL, NULL, mw->buff_size, 1, mw->buff_size,
1205 	    0, NULL, NULL, &mw->dma_tag)) {
1206 		ntb_printf(0, "Unable to create MW tag of size %zu/%zu\n",
1207 		    mw->buff_size, mw->xlat_size);
1208 		mw->xlat_size = 0;
1209 		mw->buff_size = 0;
1210 		return (ENOMEM);
1211 	}
1212 	if (bus_dmamem_alloc(mw->dma_tag, (void **)&mw->virt_addr,
1213 	    BUS_DMA_WAITOK | BUS_DMA_ZERO, &mw->dma_map)) {
1214 		bus_dma_tag_destroy(mw->dma_tag);
1215 		ntb_printf(0, "Unable to allocate MW buffer of size %zu/%zu\n",
1216 		    mw->buff_size, mw->xlat_size);
1217 		mw->xlat_size = 0;
1218 		mw->buff_size = 0;
1219 		return (ENOMEM);
1220 	}
1221 	if (bus_dmamap_load(mw->dma_tag, mw->dma_map, mw->virt_addr,
1222 	    mw->buff_size, ntb_load_cb, &cba, BUS_DMA_NOWAIT) || cba.error) {
1223 		bus_dmamem_free(mw->dma_tag, mw->virt_addr, mw->dma_map);
1224 		bus_dma_tag_destroy(mw->dma_tag);
1225 		ntb_printf(0, "Unable to load MW buffer of size %zu/%zu\n",
1226 		    mw->buff_size, mw->xlat_size);
1227 		mw->xlat_size = 0;
1228 		mw->buff_size = 0;
1229 		return (ENOMEM);
1230 	}
1231 	mw->dma_addr = cba.addr;
1232 
1233 	/* Notify HW the memory location of the receive buffer */
1234 	rc = ntb_mw_set_trans(nt->dev, num_mw, mw->dma_addr, mw->xlat_size);
1235 	if (rc) {
1236 		ntb_printf(0, "Unable to set mw%d translation\n", num_mw);
1237 		ntb_free_mw(nt, num_mw);
1238 		return (rc);
1239 	}
1240 
1241 	return (0);
1242 }
1243 
1244 static void
1245 ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
1246 {
1247 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
1248 
1249 	if (mw->virt_addr == NULL)
1250 		return;
1251 
1252 	ntb_mw_clear_trans(nt->dev, num_mw);
1253 	bus_dmamap_unload(mw->dma_tag, mw->dma_map);
1254 	bus_dmamem_free(mw->dma_tag, mw->virt_addr, mw->dma_map);
1255 	bus_dma_tag_destroy(mw->dma_tag);
1256 	mw->xlat_size = 0;
1257 	mw->buff_size = 0;
1258 	mw->virt_addr = NULL;
1259 }
1260 
1261 static int
1262 ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt, unsigned int qp_num)
1263 {
1264 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
1265 	struct ntb_transport_mw *mw;
1266 	void *offset;
1267 	ntb_q_idx_t i;
1268 	size_t rx_size;
1269 	unsigned num_qps_mw, mw_num, mw_count;
1270 
1271 	mw_count = nt->mw_count;
1272 	mw_num = QP_TO_MW(nt, qp_num);
1273 	mw = &nt->mw_vec[mw_num];
1274 
1275 	if (mw->virt_addr == NULL)
1276 		return (ENOMEM);
1277 
1278 	if (mw_num < nt->qp_count % mw_count)
1279 		num_qps_mw = nt->qp_count / mw_count + 1;
1280 	else
1281 		num_qps_mw = nt->qp_count / mw_count;
1282 
1283 	rx_size = mw->xlat_size / num_qps_mw;
1284 	qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
1285 	rx_size -= sizeof(struct ntb_rx_info);
1286 
1287 	qp->remote_rx_info = (void*)(qp->rx_buff + rx_size);
1288 
1289 	/* Due to house-keeping, there must be at least 2 buffs */
1290 	qp->rx_max_frame = qmin(transport_mtu, rx_size / 2);
1291 	qp->rx_max_entry = rx_size / qp->rx_max_frame;
1292 	qp->rx_index = 0;
1293 
1294 	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
1295 
1296 	/* Set up the hdr offsets with 0s */
1297 	for (i = 0; i < qp->rx_max_entry; i++) {
1298 		offset = (void *)(qp->rx_buff + qp->rx_max_frame * (i + 1) -
1299 		    sizeof(struct ntb_payload_header));
1300 		memset(offset, 0, sizeof(struct ntb_payload_header));
1301 	}
1302 
1303 	qp->rx_pkts = 0;
1304 	qp->tx_pkts = 0;
1305 	qp->tx_index = 0;
1306 
1307 	return (0);
1308 }
1309 
1310 static void
1311 ntb_qp_link_work(void *arg)
1312 {
1313 	struct ntb_transport_qp *qp = arg;
1314 	device_t dev = qp->dev;
1315 	struct ntb_transport_ctx *nt = qp->transport;
1316 	int i;
1317 	uint32_t val;
1318 
1319 	/* Report queues that are up on our side */
1320 	for (i = 0, val = 0; i < nt->qp_count; i++) {
1321 		if (nt->qp_vec[i].client_ready)
1322 			val |= (1 << i);
1323 	}
1324 	ntb_peer_spad_write(dev, NTBT_QP_LINKS, val);
1325 
1326 	/* See if the remote side is up */
1327 	ntb_spad_read(dev, NTBT_QP_LINKS, &val);
1328 	if ((val & (1ull << qp->qp_num)) != 0) {
1329 		ntb_printf(2, "qp %d link up\n", qp->qp_num);
1330 		qp->link_is_up = true;
1331 
1332 		if (qp->event_handler != NULL)
1333 			qp->event_handler(qp->cb_data, NTB_LINK_UP);
1334 
1335 		ntb_db_clear_mask(dev, 1ull << qp->qp_num);
1336 	} else if (nt->link_is_up)
1337 		callout_reset(&qp->link_work,
1338 		    NTB_LINK_DOWN_TIMEOUT * hz / 1000, ntb_qp_link_work, qp);
1339 }
1340 
1341 /* Link down event*/
1342 static void
1343 ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
1344 {
1345 	struct ntb_transport_qp *qp;
1346 	int i;
1347 
1348 	callout_drain(&nt->link_work);
1349 	nt->link_is_up = 0;
1350 
1351 	/* Pass along the info to any clients */
1352 	for (i = 0; i < nt->qp_count; i++) {
1353 		if ((nt->qp_bitmap & (1 << i)) != 0) {
1354 			qp = &nt->qp_vec[i];
1355 			ntb_qp_link_cleanup(qp);
1356 			callout_drain(&qp->link_work);
1357 		}
1358 	}
1359 
1360 	/*
1361 	 * The scratchpad registers keep the values if the remote side
1362 	 * goes down, blast them now to give them a sane value the next
1363 	 * time they are accessed
1364 	 */
1365 	ntb_spad_clear(nt->dev);
1366 }
1367 
1368 static void
1369 ntb_transport_link_cleanup_work(void *arg, int pending __unused)
1370 {
1371 
1372 	ntb_transport_link_cleanup(arg);
1373 }
1374 
1375 static void
1376 ntb_qp_link_down(struct ntb_transport_qp *qp)
1377 {
1378 
1379 	ntb_qp_link_cleanup(qp);
1380 }
1381 
1382 static void
1383 ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
1384 {
1385 
1386 	qp->link_is_up = false;
1387 	ntb_db_set_mask(qp->dev, 1ull << qp->qp_num);
1388 
1389 	qp->tx_index = qp->rx_index = 0;
1390 	qp->tx_bytes = qp->rx_bytes = 0;
1391 	qp->tx_pkts = qp->rx_pkts = 0;
1392 
1393 	qp->rx_ring_empty = 0;
1394 	qp->tx_ring_full = 0;
1395 
1396 	qp->rx_err_no_buf = qp->tx_err_no_buf = 0;
1397 	qp->rx_err_oflow = qp->rx_err_ver = 0;
1398 }
1399 
1400 static void
1401 ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
1402 {
1403 
1404 	callout_drain(&qp->link_work);
1405 	ntb_qp_link_down_reset(qp);
1406 
1407 	if (qp->event_handler != NULL)
1408 		qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
1409 }
1410 
1411 /* Link commanded down */
1412 /**
1413  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1414  * @qp: NTB transport layer queue to be disabled
1415  *
1416  * Notify NTB transport layer of client's desire to no longer receive data on
1417  * transport queue specified.  It is the client's responsibility to ensure all
1418  * entries on queue are purged or otherwise handled appropriately.
1419  */
1420 void
1421 ntb_transport_link_down(struct ntb_transport_qp *qp)
1422 {
1423 	struct ntb_transport_ctx *nt = qp->transport;
1424 	int i;
1425 	uint32_t val;
1426 
1427 	qp->client_ready = false;
1428 	for (i = 0, val = 0; i < nt->qp_count; i++) {
1429 		if (nt->qp_vec[i].client_ready)
1430 			val |= (1 << i);
1431 	}
1432 	ntb_peer_spad_write(qp->dev, NTBT_QP_LINKS, val);
1433 
1434 	if (qp->link_is_up)
1435 		ntb_send_link_down(qp);
1436 	else
1437 		callout_drain(&qp->link_work);
1438 }
1439 
1440 /**
1441  * ntb_transport_link_query - Query transport link state
1442  * @qp: NTB transport layer queue to be queried
1443  *
1444  * Query connectivity to the remote system of the NTB transport queue
1445  *
1446  * RETURNS: true for link up or false for link down
1447  */
1448 bool
1449 ntb_transport_link_query(struct ntb_transport_qp *qp)
1450 {
1451 
1452 	return (qp->link_is_up);
1453 }
1454 
1455 /**
1456  * ntb_transport_link_speed - Query transport link speed
1457  * @qp: NTB transport layer queue to be queried
1458  *
1459  * Query connection speed to the remote system of the NTB transport queue
1460  *
1461  * RETURNS: link speed in bits per second
1462  */
1463 uint64_t
1464 ntb_transport_link_speed(struct ntb_transport_qp *qp)
1465 {
1466 	struct ntb_transport_ctx *nt = qp->transport;
1467 	uint64_t rate;
1468 
1469 	if (!nt->link_is_up)
1470 		return (0);
1471 	switch (nt->link_speed) {
1472 	case NTB_SPEED_GEN1:
1473 		rate = 2500000000 * 8 / 10;
1474 		break;
1475 	case NTB_SPEED_GEN2:
1476 		rate = 5000000000 * 8 / 10;
1477 		break;
1478 	case NTB_SPEED_GEN3:
1479 		rate = 8000000000 * 128 / 130;
1480 		break;
1481 	case NTB_SPEED_GEN4:
1482 		rate = 16000000000 * 128 / 130;
1483 		break;
1484 	default:
1485 		return (0);
1486 	}
1487 	if (nt->link_width <= 0)
1488 		return (0);
1489 	return (rate * nt->link_width);
1490 }
1491 
1492 static void
1493 ntb_send_link_down(struct ntb_transport_qp *qp)
1494 {
1495 	struct ntb_queue_entry *entry;
1496 	int i, rc;
1497 
1498 	if (!qp->link_is_up)
1499 		return;
1500 
1501 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1502 		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1503 		if (entry != NULL)
1504 			break;
1505 		pause("NTB Wait for link down", hz / 10);
1506 	}
1507 
1508 	if (entry == NULL)
1509 		return;
1510 
1511 	entry->cb_data = NULL;
1512 	entry->buf = NULL;
1513 	entry->len = 0;
1514 	entry->flags = NTBT_LINK_DOWN_FLAG;
1515 
1516 	mtx_lock(&qp->tx_lock);
1517 	rc = ntb_process_tx(qp, entry);
1518 	mtx_unlock(&qp->tx_lock);
1519 	if (rc != 0)
1520 		printf("ntb: Failed to send link down\n");
1521 
1522 	ntb_qp_link_down_reset(qp);
1523 }
1524 
1525 
1526 /* List Management */
1527 
1528 static void
1529 ntb_list_add(struct mtx *lock, struct ntb_queue_entry *entry,
1530     struct ntb_queue_list *list)
1531 {
1532 
1533 	mtx_lock_spin(lock);
1534 	STAILQ_INSERT_TAIL(list, entry, entry);
1535 	mtx_unlock_spin(lock);
1536 }
1537 
1538 static struct ntb_queue_entry *
1539 ntb_list_rm(struct mtx *lock, struct ntb_queue_list *list)
1540 {
1541 	struct ntb_queue_entry *entry;
1542 
1543 	mtx_lock_spin(lock);
1544 	if (STAILQ_EMPTY(list)) {
1545 		entry = NULL;
1546 		goto out;
1547 	}
1548 	entry = STAILQ_FIRST(list);
1549 	STAILQ_REMOVE_HEAD(list, entry);
1550 out:
1551 	mtx_unlock_spin(lock);
1552 
1553 	return (entry);
1554 }
1555 
1556 static struct ntb_queue_entry *
1557 ntb_list_mv(struct mtx *lock, struct ntb_queue_list *from,
1558     struct ntb_queue_list *to)
1559 {
1560 	struct ntb_queue_entry *entry;
1561 
1562 	mtx_lock_spin(lock);
1563 	if (STAILQ_EMPTY(from)) {
1564 		entry = NULL;
1565 		goto out;
1566 	}
1567 	entry = STAILQ_FIRST(from);
1568 	STAILQ_REMOVE_HEAD(from, entry);
1569 	STAILQ_INSERT_TAIL(to, entry, entry);
1570 
1571 out:
1572 	mtx_unlock_spin(lock);
1573 	return (entry);
1574 }
1575 
1576 /**
1577  * ntb_transport_qp_num - Query the qp number
1578  * @qp: NTB transport layer queue to be queried
1579  *
1580  * Query qp number of the NTB transport queue
1581  *
1582  * RETURNS: a zero based number specifying the qp number
1583  */
1584 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1585 {
1586 
1587 	return (qp->qp_num);
1588 }
1589 
1590 /**
1591  * ntb_transport_max_size - Query the max payload size of a qp
1592  * @qp: NTB transport layer queue to be queried
1593  *
1594  * Query the maximum payload size permissible on the given qp
1595  *
1596  * RETURNS: the max payload size of a qp
1597  */
1598 unsigned int
1599 ntb_transport_max_size(struct ntb_transport_qp *qp)
1600 {
1601 
1602 	return (qp->tx_max_frame - sizeof(struct ntb_payload_header));
1603 }
1604 
1605 unsigned int
1606 ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
1607 {
1608 	unsigned int head = qp->tx_index;
1609 	unsigned int tail = qp->remote_rx_info->entry;
1610 
1611 	return (tail >= head ? tail - head : qp->tx_max_entry + tail - head);
1612 }
1613 
1614 static device_method_t ntb_transport_methods[] = {
1615 	/* Device interface */
1616 	DEVMETHOD(device_probe,     ntb_transport_probe),
1617 	DEVMETHOD(device_attach,    ntb_transport_attach),
1618 	DEVMETHOD(device_detach,    ntb_transport_detach),
1619 	/* Bus interface */
1620 	DEVMETHOD(bus_child_location_str, ntb_transport_child_location_str),
1621 	DEVMETHOD(bus_print_child,  ntb_transport_print_child),
1622 	DEVMETHOD_END
1623 };
1624 
1625 devclass_t ntb_transport_devclass;
1626 static DEFINE_CLASS_0(ntb_transport, ntb_transport_driver,
1627     ntb_transport_methods, sizeof(struct ntb_transport_ctx));
1628 DRIVER_MODULE(ntb_transport, ntb_hw, ntb_transport_driver,
1629     ntb_transport_devclass, NULL, NULL);
1630 MODULE_DEPEND(ntb_transport, ntb, 1, 1, 1);
1631 MODULE_VERSION(ntb_transport, 1);
1632