xref: /freebsd/sys/dev/ntb/ntb_transport.c (revision e0656a491411fe65ed8b9135add026358b24951f)
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;
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 	qpu = 0;
389 	qpo = imin(db_count, nt->mw_count);
390 	qpt = db_count;
391 
392 	snprintf(buf, sizeof(buf), "hint.%s.%d.config", device_get_name(dev),
393 	    device_get_unit(dev));
394 	TUNABLE_STR_FETCH(buf, cfg, sizeof(cfg));
395 	n = cfg;
396 	i = 0;
397 	while ((c = strsep(&n, ",")) != NULL) {
398 		np = c;
399 		name = strsep(&np, ":");
400 		if (name != NULL && name[0] == 0)
401 			name = NULL;
402 		qp = (np && np[0] != 0) ? strtol(np, NULL, 10) : qpo - qpu;
403 		if (qp <= 0)
404 			qp = 1;
405 
406 		if (qp > qpt - qpu) {
407 			device_printf(dev, "Not enough resources for config\n");
408 			break;
409 		}
410 
411 		nc = malloc(sizeof(*nc), M_DEVBUF, M_WAITOK | M_ZERO);
412 		nc->consumer = i;
413 		nc->qpoff = qpu;
414 		nc->qpcnt = qp;
415 		nc->dev = device_add_child(dev, name, -1);
416 		if (nc->dev == NULL) {
417 			device_printf(dev, "Can not add child.\n");
418 			break;
419 		}
420 		device_set_ivars(nc->dev, nc);
421 		*cpp = nc;
422 		cpp = &nc->next;
423 
424 		if (bootverbose) {
425 			device_printf(dev, "%d \"%s\": queues %d",
426 			    i, name, qpu);
427 			if (qp > 1)
428 				printf("-%d", qpu + qp - 1);
429 			printf("\n");
430 		}
431 
432 		qpu += qp;
433 		i++;
434 	}
435 	nt->qp_count = qpu;
436 
437 	nt->qp_vec = malloc(nt->qp_count * sizeof(*nt->qp_vec), M_NTB_T,
438 	    M_WAITOK | M_ZERO);
439 
440 	for (i = 0; i < nt->qp_count; i++)
441 		ntb_transport_init_queue(nt, i);
442 
443 	callout_init(&nt->link_work, 0);
444 	callout_init(&nt->link_watchdog, 0);
445 	TASK_INIT(&nt->link_cleanup, 0, ntb_transport_link_cleanup_work, nt);
446 	nt->link_is_up = false;
447 
448 	rc = ntb_set_ctx(dev, nt, &ntb_transport_ops);
449 	if (rc != 0)
450 		goto err;
451 
452 	ntb_link_enable(dev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
453 
454 	if (enable_xeon_watchdog != 0)
455 		callout_reset(&nt->link_watchdog, 0, xeon_link_watchdog_hb, nt);
456 
457 	bus_generic_attach(dev);
458 	return (0);
459 
460 err:
461 	free(nt->qp_vec, M_NTB_T);
462 	free(nt->mw_vec, M_NTB_T);
463 	return (rc);
464 }
465 
466 static int
467 ntb_transport_detach(device_t dev)
468 {
469 	struct ntb_transport_ctx *nt = device_get_softc(dev);
470 	struct ntb_transport_child **cpp = &nt->child;
471 	struct ntb_transport_child *nc;
472 	int error = 0, i;
473 
474 	while ((nc = *cpp) != NULL) {
475 		*cpp = (*cpp)->next;
476 		error = device_delete_child(dev, nc->dev);
477 		if (error)
478 			break;
479 		free(nc, M_DEVBUF);
480 	}
481 	KASSERT(nt->qp_bitmap == 0,
482 	    ("Some queues not freed on detach (%jx)", nt->qp_bitmap));
483 
484 	ntb_transport_link_cleanup(nt);
485 	taskqueue_drain(taskqueue_swi, &nt->link_cleanup);
486 	callout_drain(&nt->link_work);
487 	callout_drain(&nt->link_watchdog);
488 
489 	ntb_link_disable(dev);
490 	ntb_clear_ctx(dev);
491 
492 	for (i = 0; i < nt->mw_count; i++)
493 		ntb_free_mw(nt, i);
494 
495 	free(nt->qp_vec, M_NTB_T);
496 	free(nt->mw_vec, M_NTB_T);
497 	return (0);
498 }
499 
500 static int
501 ntb_transport_print_child(device_t dev, device_t child)
502 {
503 	struct ntb_transport_child *nc = device_get_ivars(child);
504 	int retval;
505 
506 	retval = bus_print_child_header(dev, child);
507 	if (nc->qpcnt > 0) {
508 		printf(" queue %d", nc->qpoff);
509 		if (nc->qpcnt > 1)
510 			printf("-%d", nc->qpoff + nc->qpcnt - 1);
511 	}
512 	retval += printf(" at consumer %d", nc->consumer);
513 	retval += bus_print_child_domain(dev, child);
514 	retval += bus_print_child_footer(dev, child);
515 
516 	return (retval);
517 }
518 
519 static int
520 ntb_transport_child_location_str(device_t dev, device_t child, char *buf,
521     size_t buflen)
522 {
523 	struct ntb_transport_child *nc = device_get_ivars(child);
524 
525 	snprintf(buf, buflen, "consumer=%d", nc->consumer);
526 	return (0);
527 }
528 
529 int
530 ntb_transport_queue_count(device_t dev)
531 {
532 	struct ntb_transport_child *nc = device_get_ivars(dev);
533 
534 	return (nc->qpcnt);
535 }
536 
537 static void
538 ntb_transport_init_queue(struct ntb_transport_ctx *nt, unsigned int qp_num)
539 {
540 	struct ntb_transport_mw *mw;
541 	struct ntb_transport_qp *qp;
542 	vm_paddr_t mw_base;
543 	uint64_t mw_size, qp_offset;
544 	size_t tx_size;
545 	unsigned num_qps_mw, mw_num, mw_count;
546 
547 	mw_count = nt->mw_count;
548 	mw_num = QP_TO_MW(nt, qp_num);
549 	mw = &nt->mw_vec[mw_num];
550 
551 	qp = &nt->qp_vec[qp_num];
552 	qp->qp_num = qp_num;
553 	qp->transport = nt;
554 	qp->dev = nt->dev;
555 	qp->client_ready = false;
556 	qp->event_handler = NULL;
557 	ntb_qp_link_down_reset(qp);
558 
559 	if (mw_num < nt->qp_count % mw_count)
560 		num_qps_mw = nt->qp_count / mw_count + 1;
561 	else
562 		num_qps_mw = nt->qp_count / mw_count;
563 
564 	mw_base = mw->phys_addr;
565 	mw_size = mw->phys_size;
566 
567 	tx_size = mw_size / num_qps_mw;
568 	qp_offset = tx_size * (qp_num / mw_count);
569 
570 	qp->tx_mw = mw->vbase + qp_offset;
571 	KASSERT(qp->tx_mw != NULL, ("uh oh?"));
572 
573 	/* XXX Assumes that a vm_paddr_t is equivalent to bus_addr_t */
574 	qp->tx_mw_phys = mw_base + qp_offset;
575 	KASSERT(qp->tx_mw_phys != 0, ("uh oh?"));
576 
577 	tx_size -= sizeof(struct ntb_rx_info);
578 	qp->rx_info = (void *)(qp->tx_mw + tx_size);
579 
580 	/* Due to house-keeping, there must be at least 2 buffs */
581 	qp->tx_max_frame = qmin(transport_mtu, tx_size / 2);
582 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
583 
584 	callout_init(&qp->link_work, 0);
585 	callout_init(&qp->rx_full, 1);
586 
587 	mtx_init(&qp->ntb_rx_q_lock, "ntb rx q", NULL, MTX_SPIN);
588 	mtx_init(&qp->ntb_tx_free_q_lock, "ntb tx free q", NULL, MTX_SPIN);
589 	mtx_init(&qp->tx_lock, "ntb transport tx", NULL, MTX_DEF);
590 	TASK_INIT(&qp->rxc_db_work, 0, ntb_transport_rxc_db, qp);
591 	qp->rxc_tq = taskqueue_create("ntbt_rx", M_WAITOK,
592 	    taskqueue_thread_enqueue, &qp->rxc_tq);
593 	taskqueue_start_threads(&qp->rxc_tq, 1, PI_NET, "%s rx%d",
594 	    device_get_nameunit(nt->dev), qp_num);
595 
596 	STAILQ_INIT(&qp->rx_post_q);
597 	STAILQ_INIT(&qp->rx_pend_q);
598 	STAILQ_INIT(&qp->tx_free_q);
599 }
600 
601 void
602 ntb_transport_free_queue(struct ntb_transport_qp *qp)
603 {
604 	struct ntb_transport_ctx *nt = qp->transport;
605 	struct ntb_queue_entry *entry;
606 
607 	callout_drain(&qp->link_work);
608 
609 	ntb_db_set_mask(qp->dev, 1ull << qp->qp_num);
610 	taskqueue_drain_all(qp->rxc_tq);
611 	taskqueue_free(qp->rxc_tq);
612 
613 	qp->cb_data = NULL;
614 	qp->rx_handler = NULL;
615 	qp->tx_handler = NULL;
616 	qp->event_handler = NULL;
617 
618 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q)))
619 		free(entry, M_NTB_T);
620 
621 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q)))
622 		free(entry, M_NTB_T);
623 
624 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
625 		free(entry, M_NTB_T);
626 
627 	nt->qp_bitmap &= ~(1 << qp->qp_num);
628 }
629 
630 /**
631  * ntb_transport_create_queue - Create a new NTB transport layer queue
632  * @rx_handler: receive callback function
633  * @tx_handler: transmit callback function
634  * @event_handler: event callback function
635  *
636  * Create a new NTB transport layer queue and provide the queue with a callback
637  * routine for both transmit and receive.  The receive callback routine will be
638  * used to pass up data when the transport has received it on the queue.   The
639  * transmit callback routine will be called when the transport has completed the
640  * transmission of the data on the queue and the data is ready to be freed.
641  *
642  * RETURNS: pointer to newly created ntb_queue, NULL on error.
643  */
644 struct ntb_transport_qp *
645 ntb_transport_create_queue(device_t dev, int q,
646     const struct ntb_queue_handlers *handlers, void *data)
647 {
648 	struct ntb_transport_child *nc = device_get_ivars(dev);
649 	struct ntb_transport_ctx *nt = device_get_softc(device_get_parent(dev));
650 	struct ntb_queue_entry *entry;
651 	struct ntb_transport_qp *qp;
652 	int i;
653 
654 	if (q < 0 || q >= nc->qpcnt)
655 		return (NULL);
656 
657 	qp = &nt->qp_vec[nc->qpoff + q];
658 	nt->qp_bitmap |= (1 << qp->qp_num);
659 	qp->cb_data = data;
660 	qp->rx_handler = handlers->rx_handler;
661 	qp->tx_handler = handlers->tx_handler;
662 	qp->event_handler = handlers->event_handler;
663 
664 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
665 		entry = malloc(sizeof(*entry), M_NTB_T, M_WAITOK | M_ZERO);
666 		entry->cb_data = data;
667 		entry->buf = NULL;
668 		entry->len = transport_mtu;
669 		entry->qp = qp;
670 		ntb_list_add(&qp->ntb_rx_q_lock, entry, &qp->rx_pend_q);
671 	}
672 
673 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
674 		entry = malloc(sizeof(*entry), M_NTB_T, M_WAITOK | M_ZERO);
675 		entry->qp = qp;
676 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
677 	}
678 
679 	ntb_db_clear(dev, 1ull << qp->qp_num);
680 	return (qp);
681 }
682 
683 /**
684  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
685  * @qp: NTB transport layer queue to be enabled
686  *
687  * Notify NTB transport layer of client readiness to use queue
688  */
689 void
690 ntb_transport_link_up(struct ntb_transport_qp *qp)
691 {
692 	struct ntb_transport_ctx *nt = qp->transport;
693 
694 	qp->client_ready = true;
695 
696 	ntb_printf(2, "qp %d client ready\n", qp->qp_num);
697 
698 	if (nt->link_is_up)
699 		callout_reset(&qp->link_work, 0, ntb_qp_link_work, qp);
700 }
701 
702 
703 
704 /* Transport Tx */
705 
706 /**
707  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
708  * @qp: NTB transport layer queue the entry is to be enqueued on
709  * @cb: per buffer pointer for callback function to use
710  * @data: pointer to data buffer that will be sent
711  * @len: length of the data buffer
712  *
713  * Enqueue a new transmit buffer onto the transport queue from which a NTB
714  * payload will be transmitted.  This assumes that a lock is being held to
715  * serialize access to the qp.
716  *
717  * RETURNS: An appropriate ERRNO error value on error, or zero for success.
718  */
719 int
720 ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
721     unsigned int len)
722 {
723 	struct ntb_queue_entry *entry;
724 	int rc;
725 
726 	if (!qp->link_is_up || len == 0) {
727 		CTR0(KTR_NTB, "TX: link not up");
728 		return (EINVAL);
729 	}
730 
731 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
732 	if (entry == NULL) {
733 		CTR0(KTR_NTB, "TX: could not get entry from tx_free_q");
734 		qp->tx_err_no_buf++;
735 		return (EBUSY);
736 	}
737 	CTR1(KTR_NTB, "TX: got entry %p from tx_free_q", entry);
738 
739 	entry->cb_data = cb;
740 	entry->buf = data;
741 	entry->len = len;
742 	entry->flags = 0;
743 
744 	mtx_lock(&qp->tx_lock);
745 	rc = ntb_process_tx(qp, entry);
746 	mtx_unlock(&qp->tx_lock);
747 	if (rc != 0) {
748 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
749 		CTR1(KTR_NTB,
750 		    "TX: process_tx failed. Returning entry %p to tx_free_q",
751 		    entry);
752 	}
753 	return (rc);
754 }
755 
756 static void
757 ntb_tx_copy_callback(void *data)
758 {
759 	struct ntb_queue_entry *entry = data;
760 	struct ntb_transport_qp *qp = entry->qp;
761 	struct ntb_payload_header *hdr = entry->x_hdr;
762 
763 	iowrite32(entry->flags | NTBT_DESC_DONE_FLAG, &hdr->flags);
764 	CTR1(KTR_NTB, "TX: hdr %p set DESC_DONE", hdr);
765 
766 	ntb_peer_db_set(qp->dev, 1ull << qp->qp_num);
767 
768 	/*
769 	 * The entry length can only be zero if the packet is intended to be a
770 	 * "link down" or similar.  Since no payload is being sent in these
771 	 * cases, there is nothing to add to the completion queue.
772 	 */
773 	if (entry->len > 0) {
774 		qp->tx_bytes += entry->len;
775 
776 		if (qp->tx_handler)
777 			qp->tx_handler(qp, qp->cb_data, entry->buf,
778 			    entry->len);
779 		else
780 			m_freem(entry->buf);
781 		entry->buf = NULL;
782 	}
783 
784 	CTR3(KTR_NTB,
785 	    "TX: entry %p sent. hdr->ver = %u, hdr->flags = 0x%x, Returning "
786 	    "to tx_free_q", entry, hdr->ver, hdr->flags);
787 	ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
788 }
789 
790 static void
791 ntb_memcpy_tx(struct ntb_queue_entry *entry, void *offset)
792 {
793 
794 	CTR2(KTR_NTB, "TX: copying %d bytes to offset %p", entry->len, offset);
795 	if (entry->buf != NULL) {
796 		m_copydata((struct mbuf *)entry->buf, 0, entry->len, offset);
797 
798 		/*
799 		 * Ensure that the data is fully copied before setting the
800 		 * flags
801 		 */
802 		wmb();
803 	}
804 
805 	ntb_tx_copy_callback(entry);
806 }
807 
808 static void
809 ntb_async_tx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry)
810 {
811 	struct ntb_payload_header *hdr;
812 	void *offset;
813 
814 	offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
815 	hdr = (struct ntb_payload_header *)((char *)offset + qp->tx_max_frame -
816 	    sizeof(struct ntb_payload_header));
817 	entry->x_hdr = hdr;
818 
819 	iowrite32(entry->len, &hdr->len);
820 	iowrite32(qp->tx_pkts, &hdr->ver);
821 
822 	ntb_memcpy_tx(entry, offset);
823 }
824 
825 static int
826 ntb_process_tx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry)
827 {
828 
829 	CTR3(KTR_NTB,
830 	    "TX: process_tx: tx_pkts=%lu, tx_index=%u, remote entry=%u",
831 	    qp->tx_pkts, qp->tx_index, qp->remote_rx_info->entry);
832 	if (qp->tx_index == qp->remote_rx_info->entry) {
833 		CTR0(KTR_NTB, "TX: ring full");
834 		qp->tx_ring_full++;
835 		return (EAGAIN);
836 	}
837 
838 	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
839 		if (qp->tx_handler != NULL)
840 			qp->tx_handler(qp, qp->cb_data, entry->buf,
841 			    EIO);
842 		else
843 			m_freem(entry->buf);
844 
845 		entry->buf = NULL;
846 		ntb_list_add(&qp->ntb_tx_free_q_lock, entry, &qp->tx_free_q);
847 		CTR1(KTR_NTB,
848 		    "TX: frame too big. returning entry %p to tx_free_q",
849 		    entry);
850 		return (0);
851 	}
852 	CTR2(KTR_NTB, "TX: copying entry %p to index %u", entry, qp->tx_index);
853 	ntb_async_tx(qp, entry);
854 
855 	qp->tx_index++;
856 	qp->tx_index %= qp->tx_max_entry;
857 
858 	qp->tx_pkts++;
859 
860 	return (0);
861 }
862 
863 /* Transport Rx */
864 static void
865 ntb_transport_rxc_db(void *arg, int pending __unused)
866 {
867 	struct ntb_transport_qp *qp = arg;
868 	uint64_t qp_mask = 1ull << qp->qp_num;
869 	int rc;
870 
871 	CTR0(KTR_NTB, "RX: transport_rx");
872 again:
873 	while ((rc = ntb_process_rxc(qp)) == 0)
874 		;
875 	CTR1(KTR_NTB, "RX: process_rxc returned %d", rc);
876 
877 	if ((ntb_db_read(qp->dev) & qp_mask) != 0) {
878 		/* If db is set, clear it and check queue once more. */
879 		ntb_db_clear(qp->dev, qp_mask);
880 		goto again;
881 	}
882 	if (qp->link_is_up)
883 		ntb_db_clear_mask(qp->dev, qp_mask);
884 }
885 
886 static int
887 ntb_process_rxc(struct ntb_transport_qp *qp)
888 {
889 	struct ntb_payload_header *hdr;
890 	struct ntb_queue_entry *entry;
891 	caddr_t offset;
892 
893 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
894 	hdr = (void *)(offset + qp->rx_max_frame -
895 	    sizeof(struct ntb_payload_header));
896 
897 	CTR1(KTR_NTB, "RX: process_rxc rx_index = %u", qp->rx_index);
898 	if ((hdr->flags & NTBT_DESC_DONE_FLAG) == 0) {
899 		CTR0(KTR_NTB, "RX: hdr not done");
900 		qp->rx_ring_empty++;
901 		return (EAGAIN);
902 	}
903 
904 	if ((hdr->flags & NTBT_LINK_DOWN_FLAG) != 0) {
905 		CTR0(KTR_NTB, "RX: link down");
906 		ntb_qp_link_down(qp);
907 		hdr->flags = 0;
908 		return (EAGAIN);
909 	}
910 
911 	if (hdr->ver != (uint32_t)qp->rx_pkts) {
912 		CTR2(KTR_NTB,"RX: ver != rx_pkts (%x != %lx). "
913 		    "Returning entry to rx_pend_q", hdr->ver, qp->rx_pkts);
914 		qp->rx_err_ver++;
915 		return (EIO);
916 	}
917 
918 	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
919 	if (entry == NULL) {
920 		qp->rx_err_no_buf++;
921 		CTR0(KTR_NTB, "RX: No entries in rx_pend_q");
922 		return (EAGAIN);
923 	}
924 	callout_stop(&qp->rx_full);
925 	CTR1(KTR_NTB, "RX: rx entry %p from rx_pend_q", entry);
926 
927 	entry->x_hdr = hdr;
928 	entry->index = qp->rx_index;
929 
930 	if (hdr->len > entry->len) {
931 		CTR2(KTR_NTB, "RX: len too long. Wanted %ju got %ju",
932 		    (uintmax_t)hdr->len, (uintmax_t)entry->len);
933 		qp->rx_err_oflow++;
934 
935 		entry->len = -EIO;
936 		entry->flags |= NTBT_DESC_DONE_FLAG;
937 
938 		ntb_complete_rxc(qp);
939 	} else {
940 		qp->rx_bytes += hdr->len;
941 		qp->rx_pkts++;
942 
943 		CTR1(KTR_NTB, "RX: received %ld rx_pkts", qp->rx_pkts);
944 
945 		entry->len = hdr->len;
946 
947 		ntb_memcpy_rx(qp, entry, offset);
948 	}
949 
950 	qp->rx_index++;
951 	qp->rx_index %= qp->rx_max_entry;
952 	return (0);
953 }
954 
955 static void
956 ntb_memcpy_rx(struct ntb_transport_qp *qp, struct ntb_queue_entry *entry,
957     void *offset)
958 {
959 	struct ifnet *ifp = entry->cb_data;
960 	unsigned int len = entry->len;
961 
962 	CTR2(KTR_NTB, "RX: copying %d bytes from offset %p", len, offset);
963 
964 	entry->buf = (void *)m_devget(offset, len, 0, ifp, NULL);
965 	if (entry->buf == NULL)
966 		entry->len = -ENOMEM;
967 
968 	/* Ensure that the data is globally visible before clearing the flag */
969 	wmb();
970 
971 	CTR2(KTR_NTB, "RX: copied entry %p to mbuf %p.", entry, entry->buf);
972 	ntb_rx_copy_callback(qp, entry);
973 }
974 
975 static inline void
976 ntb_rx_copy_callback(struct ntb_transport_qp *qp, void *data)
977 {
978 	struct ntb_queue_entry *entry;
979 
980 	entry = data;
981 	entry->flags |= NTBT_DESC_DONE_FLAG;
982 	ntb_complete_rxc(qp);
983 }
984 
985 static void
986 ntb_complete_rxc(struct ntb_transport_qp *qp)
987 {
988 	struct ntb_queue_entry *entry;
989 	struct mbuf *m;
990 	unsigned len;
991 
992 	CTR0(KTR_NTB, "RX: rx_completion_task");
993 
994 	mtx_lock_spin(&qp->ntb_rx_q_lock);
995 
996 	while (!STAILQ_EMPTY(&qp->rx_post_q)) {
997 		entry = STAILQ_FIRST(&qp->rx_post_q);
998 		if ((entry->flags & NTBT_DESC_DONE_FLAG) == 0)
999 			break;
1000 
1001 		entry->x_hdr->flags = 0;
1002 		iowrite32(entry->index, &qp->rx_info->entry);
1003 
1004 		STAILQ_REMOVE_HEAD(&qp->rx_post_q, entry);
1005 
1006 		len = entry->len;
1007 		m = entry->buf;
1008 
1009 		/*
1010 		 * Re-initialize queue_entry for reuse; rx_handler takes
1011 		 * ownership of the mbuf.
1012 		 */
1013 		entry->buf = NULL;
1014 		entry->len = transport_mtu;
1015 		entry->cb_data = qp->cb_data;
1016 
1017 		STAILQ_INSERT_TAIL(&qp->rx_pend_q, entry, entry);
1018 
1019 		mtx_unlock_spin(&qp->ntb_rx_q_lock);
1020 
1021 		CTR2(KTR_NTB, "RX: completing entry %p, mbuf %p", entry, m);
1022 		if (qp->rx_handler != NULL && qp->client_ready)
1023 			qp->rx_handler(qp, qp->cb_data, m, len);
1024 		else
1025 			m_freem(m);
1026 
1027 		mtx_lock_spin(&qp->ntb_rx_q_lock);
1028 	}
1029 
1030 	mtx_unlock_spin(&qp->ntb_rx_q_lock);
1031 }
1032 
1033 static void
1034 ntb_transport_doorbell_callback(void *data, uint32_t vector)
1035 {
1036 	struct ntb_transport_ctx *nt = data;
1037 	struct ntb_transport_qp *qp;
1038 	uint64_t vec_mask;
1039 	unsigned qp_num;
1040 
1041 	vec_mask = ntb_db_vector_mask(nt->dev, vector);
1042 	vec_mask &= nt->qp_bitmap;
1043 	if ((vec_mask & (vec_mask - 1)) != 0)
1044 		vec_mask &= ntb_db_read(nt->dev);
1045 	if (vec_mask != 0) {
1046 		ntb_db_set_mask(nt->dev, vec_mask);
1047 		ntb_db_clear(nt->dev, vec_mask);
1048 	}
1049 	while (vec_mask != 0) {
1050 		qp_num = ffsll(vec_mask) - 1;
1051 
1052 		qp = &nt->qp_vec[qp_num];
1053 		if (qp->link_is_up)
1054 			taskqueue_enqueue(qp->rxc_tq, &qp->rxc_db_work);
1055 
1056 		vec_mask &= ~(1ull << qp_num);
1057 	}
1058 }
1059 
1060 /* Link Event handler */
1061 static void
1062 ntb_transport_event_callback(void *data)
1063 {
1064 	struct ntb_transport_ctx *nt = data;
1065 
1066 	if (ntb_link_is_up(nt->dev, &nt->link_speed, &nt->link_width)) {
1067 		ntb_printf(1, "HW link up\n");
1068 		callout_reset(&nt->link_work, 0, ntb_transport_link_work, nt);
1069 	} else {
1070 		ntb_printf(1, "HW link down\n");
1071 		taskqueue_enqueue(taskqueue_swi, &nt->link_cleanup);
1072 	}
1073 }
1074 
1075 /* Link bring up */
1076 static void
1077 ntb_transport_link_work(void *arg)
1078 {
1079 	struct ntb_transport_ctx *nt = arg;
1080 	device_t dev = nt->dev;
1081 	struct ntb_transport_qp *qp;
1082 	uint64_t val64, size;
1083 	uint32_t val;
1084 	unsigned i;
1085 	int rc;
1086 
1087 	/* send the local info, in the opposite order of the way we read it */
1088 	for (i = 0; i < nt->mw_count; i++) {
1089 		size = nt->mw_vec[i].phys_size;
1090 
1091 		if (max_mw_size != 0 && size > max_mw_size)
1092 			size = max_mw_size;
1093 
1094 		ntb_peer_spad_write(dev, NTBT_MW0_SZ_HIGH + (i * 2),
1095 		    size >> 32);
1096 		ntb_peer_spad_write(dev, NTBT_MW0_SZ_LOW + (i * 2), size);
1097 	}
1098 	ntb_peer_spad_write(dev, NTBT_NUM_MWS, nt->mw_count);
1099 	ntb_peer_spad_write(dev, NTBT_NUM_QPS, nt->qp_count);
1100 	ntb_peer_spad_write(dev, NTBT_QP_LINKS, 0);
1101 	ntb_peer_spad_write(dev, NTBT_VERSION, NTB_TRANSPORT_VERSION);
1102 
1103 	/* Query the remote side for its info */
1104 	val = 0;
1105 	ntb_spad_read(dev, NTBT_VERSION, &val);
1106 	if (val != NTB_TRANSPORT_VERSION)
1107 		goto out;
1108 
1109 	ntb_spad_read(dev, NTBT_NUM_QPS, &val);
1110 	if (val != nt->qp_count)
1111 		goto out;
1112 
1113 	ntb_spad_read(dev, NTBT_NUM_MWS, &val);
1114 	if (val != nt->mw_count)
1115 		goto out;
1116 
1117 	for (i = 0; i < nt->mw_count; i++) {
1118 		ntb_spad_read(dev, NTBT_MW0_SZ_HIGH + (i * 2), &val);
1119 		val64 = (uint64_t)val << 32;
1120 
1121 		ntb_spad_read(dev, NTBT_MW0_SZ_LOW + (i * 2), &val);
1122 		val64 |= val;
1123 
1124 		rc = ntb_set_mw(nt, i, val64);
1125 		if (rc != 0)
1126 			goto free_mws;
1127 	}
1128 
1129 	nt->link_is_up = true;
1130 	ntb_printf(1, "transport link up\n");
1131 
1132 	for (i = 0; i < nt->qp_count; i++) {
1133 		qp = &nt->qp_vec[i];
1134 
1135 		ntb_transport_setup_qp_mw(nt, i);
1136 
1137 		if (qp->client_ready)
1138 			callout_reset(&qp->link_work, 0, ntb_qp_link_work, qp);
1139 	}
1140 
1141 	return;
1142 
1143 free_mws:
1144 	for (i = 0; i < nt->mw_count; i++)
1145 		ntb_free_mw(nt, i);
1146 out:
1147 	if (ntb_link_is_up(dev, &nt->link_speed, &nt->link_width))
1148 		callout_reset(&nt->link_work,
1149 		    NTB_LINK_DOWN_TIMEOUT * hz / 1000, ntb_transport_link_work, nt);
1150 }
1151 
1152 struct ntb_load_cb_args {
1153 	bus_addr_t addr;
1154 	int error;
1155 };
1156 
1157 static void
1158 ntb_load_cb(void *xsc, bus_dma_segment_t *segs, int nsegs, int error)
1159 {
1160 	struct ntb_load_cb_args *cba = (struct ntb_load_cb_args *)xsc;
1161 
1162 	if (!(cba->error = error))
1163 		cba->addr = segs[0].ds_addr;
1164 }
1165 
1166 static int
1167 ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw, size_t size)
1168 {
1169 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
1170 	struct ntb_load_cb_args cba;
1171 	size_t xlat_size, buff_size;
1172 	int rc;
1173 
1174 	if (size == 0)
1175 		return (EINVAL);
1176 
1177 	xlat_size = roundup(size, mw->xlat_align_size);
1178 	buff_size = xlat_size;
1179 
1180 	/* No need to re-setup */
1181 	if (mw->xlat_size == xlat_size)
1182 		return (0);
1183 
1184 	if (mw->buff_size != 0)
1185 		ntb_free_mw(nt, num_mw);
1186 
1187 	/* Alloc memory for receiving data.  Must be aligned */
1188 	mw->xlat_size = xlat_size;
1189 	mw->buff_size = buff_size;
1190 
1191 	if (bus_dma_tag_create(bus_get_dma_tag(nt->dev), mw->xlat_align, 0,
1192 	    mw->addr_limit, BUS_SPACE_MAXADDR,
1193 	    NULL, NULL, mw->buff_size, 1, mw->buff_size,
1194 	    0, NULL, NULL, &mw->dma_tag)) {
1195 		ntb_printf(0, "Unable to create MW tag of size %zu/%zu\n",
1196 		    mw->buff_size, mw->xlat_size);
1197 		mw->xlat_size = 0;
1198 		mw->buff_size = 0;
1199 		return (ENOMEM);
1200 	}
1201 	if (bus_dmamem_alloc(mw->dma_tag, (void **)&mw->virt_addr,
1202 	    BUS_DMA_WAITOK | BUS_DMA_ZERO, &mw->dma_map)) {
1203 		bus_dma_tag_destroy(mw->dma_tag);
1204 		ntb_printf(0, "Unable to allocate MW buffer of size %zu/%zu\n",
1205 		    mw->buff_size, mw->xlat_size);
1206 		mw->xlat_size = 0;
1207 		mw->buff_size = 0;
1208 		return (ENOMEM);
1209 	}
1210 	if (bus_dmamap_load(mw->dma_tag, mw->dma_map, mw->virt_addr,
1211 	    mw->buff_size, ntb_load_cb, &cba, BUS_DMA_NOWAIT) || cba.error) {
1212 		bus_dmamem_free(mw->dma_tag, mw->virt_addr, mw->dma_map);
1213 		bus_dma_tag_destroy(mw->dma_tag);
1214 		ntb_printf(0, "Unable to load MW buffer of size %zu/%zu\n",
1215 		    mw->buff_size, mw->xlat_size);
1216 		mw->xlat_size = 0;
1217 		mw->buff_size = 0;
1218 		return (ENOMEM);
1219 	}
1220 	mw->dma_addr = cba.addr;
1221 
1222 	/* Notify HW the memory location of the receive buffer */
1223 	rc = ntb_mw_set_trans(nt->dev, num_mw, mw->dma_addr, mw->xlat_size);
1224 	if (rc) {
1225 		ntb_printf(0, "Unable to set mw%d translation\n", num_mw);
1226 		ntb_free_mw(nt, num_mw);
1227 		return (rc);
1228 	}
1229 
1230 	return (0);
1231 }
1232 
1233 static void
1234 ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
1235 {
1236 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
1237 
1238 	if (mw->virt_addr == NULL)
1239 		return;
1240 
1241 	ntb_mw_clear_trans(nt->dev, num_mw);
1242 	bus_dmamap_unload(mw->dma_tag, mw->dma_map);
1243 	bus_dmamem_free(mw->dma_tag, mw->virt_addr, mw->dma_map);
1244 	bus_dma_tag_destroy(mw->dma_tag);
1245 	mw->xlat_size = 0;
1246 	mw->buff_size = 0;
1247 	mw->virt_addr = NULL;
1248 }
1249 
1250 static int
1251 ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt, unsigned int qp_num)
1252 {
1253 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
1254 	struct ntb_transport_mw *mw;
1255 	void *offset;
1256 	ntb_q_idx_t i;
1257 	size_t rx_size;
1258 	unsigned num_qps_mw, mw_num, mw_count;
1259 
1260 	mw_count = nt->mw_count;
1261 	mw_num = QP_TO_MW(nt, qp_num);
1262 	mw = &nt->mw_vec[mw_num];
1263 
1264 	if (mw->virt_addr == NULL)
1265 		return (ENOMEM);
1266 
1267 	if (mw_num < nt->qp_count % mw_count)
1268 		num_qps_mw = nt->qp_count / mw_count + 1;
1269 	else
1270 		num_qps_mw = nt->qp_count / mw_count;
1271 
1272 	rx_size = mw->xlat_size / num_qps_mw;
1273 	qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
1274 	rx_size -= sizeof(struct ntb_rx_info);
1275 
1276 	qp->remote_rx_info = (void*)(qp->rx_buff + rx_size);
1277 
1278 	/* Due to house-keeping, there must be at least 2 buffs */
1279 	qp->rx_max_frame = qmin(transport_mtu, rx_size / 2);
1280 	qp->rx_max_entry = rx_size / qp->rx_max_frame;
1281 	qp->rx_index = 0;
1282 
1283 	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
1284 
1285 	/* Set up the hdr offsets with 0s */
1286 	for (i = 0; i < qp->rx_max_entry; i++) {
1287 		offset = (void *)(qp->rx_buff + qp->rx_max_frame * (i + 1) -
1288 		    sizeof(struct ntb_payload_header));
1289 		memset(offset, 0, sizeof(struct ntb_payload_header));
1290 	}
1291 
1292 	qp->rx_pkts = 0;
1293 	qp->tx_pkts = 0;
1294 	qp->tx_index = 0;
1295 
1296 	return (0);
1297 }
1298 
1299 static void
1300 ntb_qp_link_work(void *arg)
1301 {
1302 	struct ntb_transport_qp *qp = arg;
1303 	device_t dev = qp->dev;
1304 	struct ntb_transport_ctx *nt = qp->transport;
1305 	int i;
1306 	uint32_t val;
1307 
1308 	/* Report queues that are up on our side */
1309 	for (i = 0, val = 0; i < nt->qp_count; i++) {
1310 		if (nt->qp_vec[i].client_ready)
1311 			val |= (1 << i);
1312 	}
1313 	ntb_peer_spad_write(dev, NTBT_QP_LINKS, val);
1314 
1315 	/* See if the remote side is up */
1316 	ntb_spad_read(dev, NTBT_QP_LINKS, &val);
1317 	if ((val & (1ull << qp->qp_num)) != 0) {
1318 		ntb_printf(2, "qp %d link up\n", qp->qp_num);
1319 		qp->link_is_up = true;
1320 
1321 		if (qp->event_handler != NULL)
1322 			qp->event_handler(qp->cb_data, NTB_LINK_UP);
1323 
1324 		ntb_db_clear_mask(dev, 1ull << qp->qp_num);
1325 	} else if (nt->link_is_up)
1326 		callout_reset(&qp->link_work,
1327 		    NTB_LINK_DOWN_TIMEOUT * hz / 1000, ntb_qp_link_work, qp);
1328 }
1329 
1330 /* Link down event*/
1331 static void
1332 ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
1333 {
1334 	struct ntb_transport_qp *qp;
1335 	int i;
1336 
1337 	callout_drain(&nt->link_work);
1338 	nt->link_is_up = 0;
1339 
1340 	/* Pass along the info to any clients */
1341 	for (i = 0; i < nt->qp_count; i++) {
1342 		if ((nt->qp_bitmap & (1 << i)) != 0) {
1343 			qp = &nt->qp_vec[i];
1344 			ntb_qp_link_cleanup(qp);
1345 			callout_drain(&qp->link_work);
1346 		}
1347 	}
1348 
1349 	/*
1350 	 * The scratchpad registers keep the values if the remote side
1351 	 * goes down, blast them now to give them a sane value the next
1352 	 * time they are accessed
1353 	 */
1354 	ntb_spad_clear(nt->dev);
1355 }
1356 
1357 static void
1358 ntb_transport_link_cleanup_work(void *arg, int pending __unused)
1359 {
1360 
1361 	ntb_transport_link_cleanup(arg);
1362 }
1363 
1364 static void
1365 ntb_qp_link_down(struct ntb_transport_qp *qp)
1366 {
1367 
1368 	ntb_qp_link_cleanup(qp);
1369 }
1370 
1371 static void
1372 ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
1373 {
1374 
1375 	qp->link_is_up = false;
1376 	ntb_db_set_mask(qp->dev, 1ull << qp->qp_num);
1377 
1378 	qp->tx_index = qp->rx_index = 0;
1379 	qp->tx_bytes = qp->rx_bytes = 0;
1380 	qp->tx_pkts = qp->rx_pkts = 0;
1381 
1382 	qp->rx_ring_empty = 0;
1383 	qp->tx_ring_full = 0;
1384 
1385 	qp->rx_err_no_buf = qp->tx_err_no_buf = 0;
1386 	qp->rx_err_oflow = qp->rx_err_ver = 0;
1387 }
1388 
1389 static void
1390 ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
1391 {
1392 
1393 	callout_drain(&qp->link_work);
1394 	ntb_qp_link_down_reset(qp);
1395 
1396 	if (qp->event_handler != NULL)
1397 		qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
1398 }
1399 
1400 /* Link commanded down */
1401 /**
1402  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1403  * @qp: NTB transport layer queue to be disabled
1404  *
1405  * Notify NTB transport layer of client's desire to no longer receive data on
1406  * transport queue specified.  It is the client's responsibility to ensure all
1407  * entries on queue are purged or otherwise handled appropriately.
1408  */
1409 void
1410 ntb_transport_link_down(struct ntb_transport_qp *qp)
1411 {
1412 	struct ntb_transport_ctx *nt = qp->transport;
1413 	int i;
1414 	uint32_t val;
1415 
1416 	qp->client_ready = false;
1417 	for (i = 0, val = 0; i < nt->qp_count; i++) {
1418 		if (nt->qp_vec[i].client_ready)
1419 			val |= (1 << i);
1420 	}
1421 	ntb_peer_spad_write(qp->dev, NTBT_QP_LINKS, val);
1422 
1423 	if (qp->link_is_up)
1424 		ntb_send_link_down(qp);
1425 	else
1426 		callout_drain(&qp->link_work);
1427 }
1428 
1429 /**
1430  * ntb_transport_link_query - Query transport link state
1431  * @qp: NTB transport layer queue to be queried
1432  *
1433  * Query connectivity to the remote system of the NTB transport queue
1434  *
1435  * RETURNS: true for link up or false for link down
1436  */
1437 bool
1438 ntb_transport_link_query(struct ntb_transport_qp *qp)
1439 {
1440 
1441 	return (qp->link_is_up);
1442 }
1443 
1444 /**
1445  * ntb_transport_link_speed - Query transport link speed
1446  * @qp: NTB transport layer queue to be queried
1447  *
1448  * Query connection speed to the remote system of the NTB transport queue
1449  *
1450  * RETURNS: link speed in bits per second
1451  */
1452 uint64_t
1453 ntb_transport_link_speed(struct ntb_transport_qp *qp)
1454 {
1455 	struct ntb_transport_ctx *nt = qp->transport;
1456 	uint64_t rate;
1457 
1458 	if (!nt->link_is_up)
1459 		return (0);
1460 	switch (nt->link_speed) {
1461 	case NTB_SPEED_GEN1:
1462 		rate = 2500000000 * 8 / 10;
1463 		break;
1464 	case NTB_SPEED_GEN2:
1465 		rate = 5000000000 * 8 / 10;
1466 		break;
1467 	case NTB_SPEED_GEN3:
1468 		rate = 8000000000 * 128 / 130;
1469 		break;
1470 	case NTB_SPEED_GEN4:
1471 		rate = 16000000000 * 128 / 130;
1472 		break;
1473 	default:
1474 		return (0);
1475 	}
1476 	if (nt->link_width <= 0)
1477 		return (0);
1478 	return (rate * nt->link_width);
1479 }
1480 
1481 static void
1482 ntb_send_link_down(struct ntb_transport_qp *qp)
1483 {
1484 	struct ntb_queue_entry *entry;
1485 	int i, rc;
1486 
1487 	if (!qp->link_is_up)
1488 		return;
1489 
1490 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1491 		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1492 		if (entry != NULL)
1493 			break;
1494 		pause("NTB Wait for link down", hz / 10);
1495 	}
1496 
1497 	if (entry == NULL)
1498 		return;
1499 
1500 	entry->cb_data = NULL;
1501 	entry->buf = NULL;
1502 	entry->len = 0;
1503 	entry->flags = NTBT_LINK_DOWN_FLAG;
1504 
1505 	mtx_lock(&qp->tx_lock);
1506 	rc = ntb_process_tx(qp, entry);
1507 	mtx_unlock(&qp->tx_lock);
1508 	if (rc != 0)
1509 		printf("ntb: Failed to send link down\n");
1510 
1511 	ntb_qp_link_down_reset(qp);
1512 }
1513 
1514 
1515 /* List Management */
1516 
1517 static void
1518 ntb_list_add(struct mtx *lock, struct ntb_queue_entry *entry,
1519     struct ntb_queue_list *list)
1520 {
1521 
1522 	mtx_lock_spin(lock);
1523 	STAILQ_INSERT_TAIL(list, entry, entry);
1524 	mtx_unlock_spin(lock);
1525 }
1526 
1527 static struct ntb_queue_entry *
1528 ntb_list_rm(struct mtx *lock, struct ntb_queue_list *list)
1529 {
1530 	struct ntb_queue_entry *entry;
1531 
1532 	mtx_lock_spin(lock);
1533 	if (STAILQ_EMPTY(list)) {
1534 		entry = NULL;
1535 		goto out;
1536 	}
1537 	entry = STAILQ_FIRST(list);
1538 	STAILQ_REMOVE_HEAD(list, entry);
1539 out:
1540 	mtx_unlock_spin(lock);
1541 
1542 	return (entry);
1543 }
1544 
1545 static struct ntb_queue_entry *
1546 ntb_list_mv(struct mtx *lock, struct ntb_queue_list *from,
1547     struct ntb_queue_list *to)
1548 {
1549 	struct ntb_queue_entry *entry;
1550 
1551 	mtx_lock_spin(lock);
1552 	if (STAILQ_EMPTY(from)) {
1553 		entry = NULL;
1554 		goto out;
1555 	}
1556 	entry = STAILQ_FIRST(from);
1557 	STAILQ_REMOVE_HEAD(from, entry);
1558 	STAILQ_INSERT_TAIL(to, entry, entry);
1559 
1560 out:
1561 	mtx_unlock_spin(lock);
1562 	return (entry);
1563 }
1564 
1565 /**
1566  * ntb_transport_qp_num - Query the qp number
1567  * @qp: NTB transport layer queue to be queried
1568  *
1569  * Query qp number of the NTB transport queue
1570  *
1571  * RETURNS: a zero based number specifying the qp number
1572  */
1573 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1574 {
1575 
1576 	return (qp->qp_num);
1577 }
1578 
1579 /**
1580  * ntb_transport_max_size - Query the max payload size of a qp
1581  * @qp: NTB transport layer queue to be queried
1582  *
1583  * Query the maximum payload size permissible on the given qp
1584  *
1585  * RETURNS: the max payload size of a qp
1586  */
1587 unsigned int
1588 ntb_transport_max_size(struct ntb_transport_qp *qp)
1589 {
1590 
1591 	return (qp->tx_max_frame - sizeof(struct ntb_payload_header));
1592 }
1593 
1594 unsigned int
1595 ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
1596 {
1597 	unsigned int head = qp->tx_index;
1598 	unsigned int tail = qp->remote_rx_info->entry;
1599 
1600 	return (tail >= head ? tail - head : qp->tx_max_entry + tail - head);
1601 }
1602 
1603 static device_method_t ntb_transport_methods[] = {
1604 	/* Device interface */
1605 	DEVMETHOD(device_probe,     ntb_transport_probe),
1606 	DEVMETHOD(device_attach,    ntb_transport_attach),
1607 	DEVMETHOD(device_detach,    ntb_transport_detach),
1608 	/* Bus interface */
1609 	DEVMETHOD(bus_child_location_str, ntb_transport_child_location_str),
1610 	DEVMETHOD(bus_print_child,  ntb_transport_print_child),
1611 	DEVMETHOD_END
1612 };
1613 
1614 devclass_t ntb_transport_devclass;
1615 static DEFINE_CLASS_0(ntb_transport, ntb_transport_driver,
1616     ntb_transport_methods, sizeof(struct ntb_transport_ctx));
1617 DRIVER_MODULE(ntb_transport, ntb_hw, ntb_transport_driver,
1618     ntb_transport_devclass, NULL, NULL);
1619 MODULE_DEPEND(ntb_transport, ntb, 1, 1, 1);
1620 MODULE_VERSION(ntb_transport, 1);
1621