xref: /linux/drivers/ntb/ntb_transport.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34)
1 /*
2  * This file is provided under a dual BSD/GPLv2 license.  When using or
3  *   redistributing this file, you may do so under either license.
4  *
5  *   GPL LICENSE SUMMARY
6  *
7  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
8  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
9  *
10  *   This program is free software; you can redistribute it and/or modify
11  *   it under the terms of version 2 of the GNU General Public License as
12  *   published by the Free Software Foundation.
13  *
14  *   BSD LICENSE
15  *
16  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
17  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
18  *
19  *   Redistribution and use in source and binary forms, with or without
20  *   modification, are permitted provided that the following conditions
21  *   are met:
22  *
23  *     * Redistributions of source code must retain the above copyright
24  *       notice, this list of conditions and the following disclaimer.
25  *     * Redistributions in binary form must reproduce the above copy
26  *       notice, this list of conditions and the following disclaimer in
27  *       the documentation and/or other materials provided with the
28  *       distribution.
29  *     * Neither the name of Intel Corporation nor the names of its
30  *       contributors may be used to endorse or promote products derived
31  *       from this software without specific prior written permission.
32  *
33  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
34  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
35  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
36  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
37  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
40  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
41  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
42  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
43  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44  *
45  * PCIe NTB Transport Linux driver
46  *
47  * Contact Information:
48  * Jon Mason <jon.mason@intel.com>
49  */
50 #include <linux/debugfs.h>
51 #include <linux/delay.h>
52 #include <linux/dmaengine.h>
53 #include <linux/dma-mapping.h>
54 #include <linux/errno.h>
55 #include <linux/export.h>
56 #include <linux/interrupt.h>
57 #include <linux/module.h>
58 #include <linux/pci.h>
59 #include <linux/slab.h>
60 #include <linux/types.h>
61 #include <linux/uaccess.h>
62 #include "linux/ntb.h"
63 #include "linux/ntb_transport.h"
64 
65 #define NTB_TRANSPORT_VERSION	4
66 #define NTB_TRANSPORT_VER	"4"
67 #define NTB_TRANSPORT_NAME	"ntb_transport"
68 #define NTB_TRANSPORT_DESC	"Software Queue-Pair Transport over NTB"
69 
70 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
71 MODULE_VERSION(NTB_TRANSPORT_VER);
72 MODULE_LICENSE("Dual BSD/GPL");
73 MODULE_AUTHOR("Intel Corporation");
74 
75 static unsigned long max_mw_size;
76 module_param(max_mw_size, ulong, 0644);
77 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
78 
79 static unsigned int transport_mtu = 0x10000;
80 module_param(transport_mtu, uint, 0644);
81 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
82 
83 static unsigned char max_num_clients;
84 module_param(max_num_clients, byte, 0644);
85 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
86 
87 static unsigned int copy_bytes = 1024;
88 module_param(copy_bytes, uint, 0644);
89 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
90 
91 static bool use_dma;
92 module_param(use_dma, bool, 0644);
93 MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
94 
95 static struct dentry *nt_debugfs_dir;
96 
97 struct ntb_queue_entry {
98 	/* ntb_queue list reference */
99 	struct list_head entry;
100 	/* pointers to data to be transferred */
101 	void *cb_data;
102 	void *buf;
103 	unsigned int len;
104 	unsigned int flags;
105 
106 	struct ntb_transport_qp *qp;
107 	union {
108 		struct ntb_payload_header __iomem *tx_hdr;
109 		struct ntb_payload_header *rx_hdr;
110 	};
111 	unsigned int index;
112 };
113 
114 struct ntb_rx_info {
115 	unsigned int entry;
116 };
117 
118 struct ntb_transport_qp {
119 	struct ntb_transport_ctx *transport;
120 	struct ntb_dev *ndev;
121 	void *cb_data;
122 	struct dma_chan *dma_chan;
123 
124 	bool client_ready;
125 	bool link_is_up;
126 
127 	u8 qp_num;	/* Only 64 QP's are allowed.  0-63 */
128 	u64 qp_bit;
129 
130 	struct ntb_rx_info __iomem *rx_info;
131 	struct ntb_rx_info *remote_rx_info;
132 
133 	void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
134 			   void *data, int len);
135 	struct list_head tx_free_q;
136 	spinlock_t ntb_tx_free_q_lock;
137 	void __iomem *tx_mw;
138 	dma_addr_t tx_mw_phys;
139 	unsigned int tx_index;
140 	unsigned int tx_max_entry;
141 	unsigned int tx_max_frame;
142 
143 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
144 			   void *data, int len);
145 	struct list_head rx_post_q;
146 	struct list_head rx_pend_q;
147 	struct list_head rx_free_q;
148 	/* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
149 	spinlock_t ntb_rx_q_lock;
150 	void *rx_buff;
151 	unsigned int rx_index;
152 	unsigned int rx_max_entry;
153 	unsigned int rx_max_frame;
154 	dma_cookie_t last_cookie;
155 	struct tasklet_struct rxc_db_work;
156 
157 	void (*event_handler)(void *data, int status);
158 	struct delayed_work link_work;
159 	struct work_struct link_cleanup;
160 
161 	struct dentry *debugfs_dir;
162 	struct dentry *debugfs_stats;
163 
164 	/* Stats */
165 	u64 rx_bytes;
166 	u64 rx_pkts;
167 	u64 rx_ring_empty;
168 	u64 rx_err_no_buf;
169 	u64 rx_err_oflow;
170 	u64 rx_err_ver;
171 	u64 rx_memcpy;
172 	u64 rx_async;
173 	u64 tx_bytes;
174 	u64 tx_pkts;
175 	u64 tx_ring_full;
176 	u64 tx_err_no_buf;
177 	u64 tx_memcpy;
178 	u64 tx_async;
179 };
180 
181 struct ntb_transport_mw {
182 	phys_addr_t phys_addr;
183 	resource_size_t phys_size;
184 	resource_size_t xlat_align;
185 	resource_size_t xlat_align_size;
186 	void __iomem *vbase;
187 	size_t xlat_size;
188 	size_t buff_size;
189 	void *virt_addr;
190 	dma_addr_t dma_addr;
191 };
192 
193 struct ntb_transport_client_dev {
194 	struct list_head entry;
195 	struct ntb_transport_ctx *nt;
196 	struct device dev;
197 };
198 
199 struct ntb_transport_ctx {
200 	struct list_head entry;
201 	struct list_head client_devs;
202 
203 	struct ntb_dev *ndev;
204 
205 	struct ntb_transport_mw *mw_vec;
206 	struct ntb_transport_qp *qp_vec;
207 	unsigned int mw_count;
208 	unsigned int qp_count;
209 	u64 qp_bitmap;
210 	u64 qp_bitmap_free;
211 
212 	bool link_is_up;
213 	struct delayed_work link_work;
214 	struct work_struct link_cleanup;
215 
216 	struct dentry *debugfs_node_dir;
217 };
218 
219 enum {
220 	DESC_DONE_FLAG = BIT(0),
221 	LINK_DOWN_FLAG = BIT(1),
222 };
223 
224 struct ntb_payload_header {
225 	unsigned int ver;
226 	unsigned int len;
227 	unsigned int flags;
228 };
229 
230 enum {
231 	VERSION = 0,
232 	QP_LINKS,
233 	NUM_QPS,
234 	NUM_MWS,
235 	MW0_SZ_HIGH,
236 	MW0_SZ_LOW,
237 	MW1_SZ_HIGH,
238 	MW1_SZ_LOW,
239 	MAX_SPAD,
240 };
241 
242 #define dev_client_dev(__dev) \
243 	container_of((__dev), struct ntb_transport_client_dev, dev)
244 
245 #define drv_client(__drv) \
246 	container_of((__drv), struct ntb_transport_client, driver)
247 
248 #define QP_TO_MW(nt, qp)	((qp) % nt->mw_count)
249 #define NTB_QP_DEF_NUM_ENTRIES	100
250 #define NTB_LINK_DOWN_TIMEOUT	10
251 
252 static void ntb_transport_rxc_db(unsigned long data);
253 static const struct ntb_ctx_ops ntb_transport_ops;
254 static struct ntb_client ntb_transport_client;
255 
256 static int ntb_transport_bus_match(struct device *dev,
257 				   struct device_driver *drv)
258 {
259 	return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
260 }
261 
262 static int ntb_transport_bus_probe(struct device *dev)
263 {
264 	const struct ntb_transport_client *client;
265 	int rc = -EINVAL;
266 
267 	get_device(dev);
268 
269 	client = drv_client(dev->driver);
270 	rc = client->probe(dev);
271 	if (rc)
272 		put_device(dev);
273 
274 	return rc;
275 }
276 
277 static int ntb_transport_bus_remove(struct device *dev)
278 {
279 	const struct ntb_transport_client *client;
280 
281 	client = drv_client(dev->driver);
282 	client->remove(dev);
283 
284 	put_device(dev);
285 
286 	return 0;
287 }
288 
289 static struct bus_type ntb_transport_bus = {
290 	.name = "ntb_transport",
291 	.match = ntb_transport_bus_match,
292 	.probe = ntb_transport_bus_probe,
293 	.remove = ntb_transport_bus_remove,
294 };
295 
296 static LIST_HEAD(ntb_transport_list);
297 
298 static int ntb_bus_init(struct ntb_transport_ctx *nt)
299 {
300 	list_add(&nt->entry, &ntb_transport_list);
301 	return 0;
302 }
303 
304 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
305 {
306 	struct ntb_transport_client_dev *client_dev, *cd;
307 
308 	list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
309 		dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
310 			dev_name(&client_dev->dev));
311 		list_del(&client_dev->entry);
312 		device_unregister(&client_dev->dev);
313 	}
314 
315 	list_del(&nt->entry);
316 }
317 
318 static void ntb_transport_client_release(struct device *dev)
319 {
320 	struct ntb_transport_client_dev *client_dev;
321 
322 	client_dev = dev_client_dev(dev);
323 	kfree(client_dev);
324 }
325 
326 /**
327  * ntb_transport_unregister_client_dev - Unregister NTB client device
328  * @device_name: Name of NTB client device
329  *
330  * Unregister an NTB client device with the NTB transport layer
331  */
332 void ntb_transport_unregister_client_dev(char *device_name)
333 {
334 	struct ntb_transport_client_dev *client, *cd;
335 	struct ntb_transport_ctx *nt;
336 
337 	list_for_each_entry(nt, &ntb_transport_list, entry)
338 		list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
339 			if (!strncmp(dev_name(&client->dev), device_name,
340 				     strlen(device_name))) {
341 				list_del(&client->entry);
342 				device_unregister(&client->dev);
343 			}
344 }
345 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
346 
347 /**
348  * ntb_transport_register_client_dev - Register NTB client device
349  * @device_name: Name of NTB client device
350  *
351  * Register an NTB client device with the NTB transport layer
352  */
353 int ntb_transport_register_client_dev(char *device_name)
354 {
355 	struct ntb_transport_client_dev *client_dev;
356 	struct ntb_transport_ctx *nt;
357 	int node;
358 	int rc, i = 0;
359 
360 	if (list_empty(&ntb_transport_list))
361 		return -ENODEV;
362 
363 	list_for_each_entry(nt, &ntb_transport_list, entry) {
364 		struct device *dev;
365 
366 		node = dev_to_node(&nt->ndev->dev);
367 
368 		client_dev = kzalloc_node(sizeof(*client_dev),
369 					  GFP_KERNEL, node);
370 		if (!client_dev) {
371 			rc = -ENOMEM;
372 			goto err;
373 		}
374 
375 		dev = &client_dev->dev;
376 
377 		/* setup and register client devices */
378 		dev_set_name(dev, "%s%d", device_name, i);
379 		dev->bus = &ntb_transport_bus;
380 		dev->release = ntb_transport_client_release;
381 		dev->parent = &nt->ndev->dev;
382 
383 		rc = device_register(dev);
384 		if (rc) {
385 			kfree(client_dev);
386 			goto err;
387 		}
388 
389 		list_add_tail(&client_dev->entry, &nt->client_devs);
390 		i++;
391 	}
392 
393 	return 0;
394 
395 err:
396 	ntb_transport_unregister_client_dev(device_name);
397 
398 	return rc;
399 }
400 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
401 
402 /**
403  * ntb_transport_register_client - Register NTB client driver
404  * @drv: NTB client driver to be registered
405  *
406  * Register an NTB client driver with the NTB transport layer
407  *
408  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
409  */
410 int ntb_transport_register_client(struct ntb_transport_client *drv)
411 {
412 	drv->driver.bus = &ntb_transport_bus;
413 
414 	if (list_empty(&ntb_transport_list))
415 		return -ENODEV;
416 
417 	return driver_register(&drv->driver);
418 }
419 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
420 
421 /**
422  * ntb_transport_unregister_client - Unregister NTB client driver
423  * @drv: NTB client driver to be unregistered
424  *
425  * Unregister an NTB client driver with the NTB transport layer
426  *
427  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
428  */
429 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
430 {
431 	driver_unregister(&drv->driver);
432 }
433 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
434 
435 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
436 			    loff_t *offp)
437 {
438 	struct ntb_transport_qp *qp;
439 	char *buf;
440 	ssize_t ret, out_offset, out_count;
441 
442 	qp = filp->private_data;
443 
444 	if (!qp || !qp->link_is_up)
445 		return 0;
446 
447 	out_count = 1000;
448 
449 	buf = kmalloc(out_count, GFP_KERNEL);
450 	if (!buf)
451 		return -ENOMEM;
452 
453 	out_offset = 0;
454 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
455 			       "NTB QP stats\n");
456 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
457 			       "rx_bytes - \t%llu\n", qp->rx_bytes);
458 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
459 			       "rx_pkts - \t%llu\n", qp->rx_pkts);
460 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
461 			       "rx_memcpy - \t%llu\n", qp->rx_memcpy);
462 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
463 			       "rx_async - \t%llu\n", qp->rx_async);
464 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
465 			       "rx_ring_empty - %llu\n", qp->rx_ring_empty);
466 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
467 			       "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
468 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
469 			       "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
470 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
471 			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
472 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
473 			       "rx_buff - \t%p\n", qp->rx_buff);
474 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
475 			       "rx_index - \t%u\n", qp->rx_index);
476 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
477 			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
478 
479 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
480 			       "tx_bytes - \t%llu\n", qp->tx_bytes);
481 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
482 			       "tx_pkts - \t%llu\n", qp->tx_pkts);
483 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
484 			       "tx_memcpy - \t%llu\n", qp->tx_memcpy);
485 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
486 			       "tx_async - \t%llu\n", qp->tx_async);
487 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
488 			       "tx_ring_full - \t%llu\n", qp->tx_ring_full);
489 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
490 			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
491 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
492 			       "tx_mw - \t%p\n", qp->tx_mw);
493 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
494 			       "tx_index - \t%u\n", qp->tx_index);
495 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
496 			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
497 
498 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
499 			       "\nQP Link %s\n",
500 			       qp->link_is_up ? "Up" : "Down");
501 	if (out_offset > out_count)
502 		out_offset = out_count;
503 
504 	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
505 	kfree(buf);
506 	return ret;
507 }
508 
509 static const struct file_operations ntb_qp_debugfs_stats = {
510 	.owner = THIS_MODULE,
511 	.open = simple_open,
512 	.read = debugfs_read,
513 };
514 
515 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
516 			 struct list_head *list)
517 {
518 	unsigned long flags;
519 
520 	spin_lock_irqsave(lock, flags);
521 	list_add_tail(entry, list);
522 	spin_unlock_irqrestore(lock, flags);
523 }
524 
525 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
526 					   struct list_head *list)
527 {
528 	struct ntb_queue_entry *entry;
529 	unsigned long flags;
530 
531 	spin_lock_irqsave(lock, flags);
532 	if (list_empty(list)) {
533 		entry = NULL;
534 		goto out;
535 	}
536 	entry = list_first_entry(list, struct ntb_queue_entry, entry);
537 	list_del(&entry->entry);
538 out:
539 	spin_unlock_irqrestore(lock, flags);
540 
541 	return entry;
542 }
543 
544 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
545 					   struct list_head *list,
546 					   struct list_head *to_list)
547 {
548 	struct ntb_queue_entry *entry;
549 	unsigned long flags;
550 
551 	spin_lock_irqsave(lock, flags);
552 
553 	if (list_empty(list)) {
554 		entry = NULL;
555 	} else {
556 		entry = list_first_entry(list, struct ntb_queue_entry, entry);
557 		list_move_tail(&entry->entry, to_list);
558 	}
559 
560 	spin_unlock_irqrestore(lock, flags);
561 
562 	return entry;
563 }
564 
565 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
566 				     unsigned int qp_num)
567 {
568 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
569 	struct ntb_transport_mw *mw;
570 	unsigned int rx_size, num_qps_mw;
571 	unsigned int mw_num, mw_count, qp_count;
572 	unsigned int i;
573 
574 	mw_count = nt->mw_count;
575 	qp_count = nt->qp_count;
576 
577 	mw_num = QP_TO_MW(nt, qp_num);
578 	mw = &nt->mw_vec[mw_num];
579 
580 	if (!mw->virt_addr)
581 		return -ENOMEM;
582 
583 	if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
584 		num_qps_mw = qp_count / mw_count + 1;
585 	else
586 		num_qps_mw = qp_count / mw_count;
587 
588 	rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
589 	qp->rx_buff = mw->virt_addr + rx_size * qp_num / mw_count;
590 	rx_size -= sizeof(struct ntb_rx_info);
591 
592 	qp->remote_rx_info = qp->rx_buff + rx_size;
593 
594 	/* Due to housekeeping, there must be atleast 2 buffs */
595 	qp->rx_max_frame = min(transport_mtu, rx_size / 2);
596 	qp->rx_max_entry = rx_size / qp->rx_max_frame;
597 	qp->rx_index = 0;
598 
599 	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
600 
601 	/* setup the hdr offsets with 0's */
602 	for (i = 0; i < qp->rx_max_entry; i++) {
603 		void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
604 				sizeof(struct ntb_payload_header));
605 		memset(offset, 0, sizeof(struct ntb_payload_header));
606 	}
607 
608 	qp->rx_pkts = 0;
609 	qp->tx_pkts = 0;
610 	qp->tx_index = 0;
611 
612 	return 0;
613 }
614 
615 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
616 {
617 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
618 	struct pci_dev *pdev = nt->ndev->pdev;
619 
620 	if (!mw->virt_addr)
621 		return;
622 
623 	ntb_mw_clear_trans(nt->ndev, num_mw);
624 	dma_free_coherent(&pdev->dev, mw->buff_size,
625 			  mw->virt_addr, mw->dma_addr);
626 	mw->xlat_size = 0;
627 	mw->buff_size = 0;
628 	mw->virt_addr = NULL;
629 }
630 
631 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
632 		      resource_size_t size)
633 {
634 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
635 	struct pci_dev *pdev = nt->ndev->pdev;
636 	size_t xlat_size, buff_size;
637 	int rc;
638 
639 	if (!size)
640 		return -EINVAL;
641 
642 	xlat_size = round_up(size, mw->xlat_align_size);
643 	buff_size = round_up(size, mw->xlat_align);
644 
645 	/* No need to re-setup */
646 	if (mw->xlat_size == xlat_size)
647 		return 0;
648 
649 	if (mw->buff_size)
650 		ntb_free_mw(nt, num_mw);
651 
652 	/* Alloc memory for receiving data.  Must be aligned */
653 	mw->xlat_size = xlat_size;
654 	mw->buff_size = buff_size;
655 
656 	mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
657 					   &mw->dma_addr, GFP_KERNEL);
658 	if (!mw->virt_addr) {
659 		mw->xlat_size = 0;
660 		mw->buff_size = 0;
661 		dev_err(&pdev->dev, "Unable to alloc MW buff of size %zu\n",
662 			buff_size);
663 		return -ENOMEM;
664 	}
665 
666 	/*
667 	 * we must ensure that the memory address allocated is BAR size
668 	 * aligned in order for the XLAT register to take the value. This
669 	 * is a requirement of the hardware. It is recommended to setup CMA
670 	 * for BAR sizes equal or greater than 4MB.
671 	 */
672 	if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
673 		dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
674 			&mw->dma_addr);
675 		ntb_free_mw(nt, num_mw);
676 		return -ENOMEM;
677 	}
678 
679 	/* Notify HW the memory location of the receive buffer */
680 	rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
681 	if (rc) {
682 		dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
683 		ntb_free_mw(nt, num_mw);
684 		return -EIO;
685 	}
686 
687 	return 0;
688 }
689 
690 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
691 {
692 	qp->link_is_up = false;
693 
694 	qp->tx_index = 0;
695 	qp->rx_index = 0;
696 	qp->rx_bytes = 0;
697 	qp->rx_pkts = 0;
698 	qp->rx_ring_empty = 0;
699 	qp->rx_err_no_buf = 0;
700 	qp->rx_err_oflow = 0;
701 	qp->rx_err_ver = 0;
702 	qp->rx_memcpy = 0;
703 	qp->rx_async = 0;
704 	qp->tx_bytes = 0;
705 	qp->tx_pkts = 0;
706 	qp->tx_ring_full = 0;
707 	qp->tx_err_no_buf = 0;
708 	qp->tx_memcpy = 0;
709 	qp->tx_async = 0;
710 }
711 
712 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
713 {
714 	struct ntb_transport_ctx *nt = qp->transport;
715 	struct pci_dev *pdev = nt->ndev->pdev;
716 
717 	dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
718 
719 	cancel_delayed_work_sync(&qp->link_work);
720 	ntb_qp_link_down_reset(qp);
721 
722 	if (qp->event_handler)
723 		qp->event_handler(qp->cb_data, qp->link_is_up);
724 }
725 
726 static void ntb_qp_link_cleanup_work(struct work_struct *work)
727 {
728 	struct ntb_transport_qp *qp = container_of(work,
729 						   struct ntb_transport_qp,
730 						   link_cleanup);
731 	struct ntb_transport_ctx *nt = qp->transport;
732 
733 	ntb_qp_link_cleanup(qp);
734 
735 	if (nt->link_is_up)
736 		schedule_delayed_work(&qp->link_work,
737 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
738 }
739 
740 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
741 {
742 	schedule_work(&qp->link_cleanup);
743 }
744 
745 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
746 {
747 	struct ntb_transport_qp *qp;
748 	u64 qp_bitmap_alloc;
749 	int i;
750 
751 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
752 
753 	/* Pass along the info to any clients */
754 	for (i = 0; i < nt->qp_count; i++)
755 		if (qp_bitmap_alloc & BIT_ULL(i)) {
756 			qp = &nt->qp_vec[i];
757 			ntb_qp_link_cleanup(qp);
758 			cancel_work_sync(&qp->link_cleanup);
759 			cancel_delayed_work_sync(&qp->link_work);
760 		}
761 
762 	if (!nt->link_is_up)
763 		cancel_delayed_work_sync(&nt->link_work);
764 
765 	/* The scratchpad registers keep the values if the remote side
766 	 * goes down, blast them now to give them a sane value the next
767 	 * time they are accessed
768 	 */
769 	for (i = 0; i < MAX_SPAD; i++)
770 		ntb_spad_write(nt->ndev, i, 0);
771 }
772 
773 static void ntb_transport_link_cleanup_work(struct work_struct *work)
774 {
775 	struct ntb_transport_ctx *nt =
776 		container_of(work, struct ntb_transport_ctx, link_cleanup);
777 
778 	ntb_transport_link_cleanup(nt);
779 }
780 
781 static void ntb_transport_event_callback(void *data)
782 {
783 	struct ntb_transport_ctx *nt = data;
784 
785 	if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
786 		schedule_delayed_work(&nt->link_work, 0);
787 	else
788 		schedule_work(&nt->link_cleanup);
789 }
790 
791 static void ntb_transport_link_work(struct work_struct *work)
792 {
793 	struct ntb_transport_ctx *nt =
794 		container_of(work, struct ntb_transport_ctx, link_work.work);
795 	struct ntb_dev *ndev = nt->ndev;
796 	struct pci_dev *pdev = ndev->pdev;
797 	resource_size_t size;
798 	u32 val;
799 	int rc, i, spad;
800 
801 	/* send the local info, in the opposite order of the way we read it */
802 	for (i = 0; i < nt->mw_count; i++) {
803 		size = nt->mw_vec[i].phys_size;
804 
805 		if (max_mw_size && size > max_mw_size)
806 			size = max_mw_size;
807 
808 		spad = MW0_SZ_HIGH + (i * 2);
809 		ntb_peer_spad_write(ndev, spad, (u32)(size >> 32));
810 
811 		spad = MW0_SZ_LOW + (i * 2);
812 		ntb_peer_spad_write(ndev, spad, (u32)size);
813 	}
814 
815 	ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
816 
817 	ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
818 
819 	ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
820 
821 	/* Query the remote side for its info */
822 	val = ntb_spad_read(ndev, VERSION);
823 	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
824 	if (val != NTB_TRANSPORT_VERSION)
825 		goto out;
826 
827 	val = ntb_spad_read(ndev, NUM_QPS);
828 	dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
829 	if (val != nt->qp_count)
830 		goto out;
831 
832 	val = ntb_spad_read(ndev, NUM_MWS);
833 	dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
834 	if (val != nt->mw_count)
835 		goto out;
836 
837 	for (i = 0; i < nt->mw_count; i++) {
838 		u64 val64;
839 
840 		val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
841 		val64 = (u64)val << 32;
842 
843 		val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
844 		val64 |= val;
845 
846 		dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
847 
848 		rc = ntb_set_mw(nt, i, val64);
849 		if (rc)
850 			goto out1;
851 	}
852 
853 	nt->link_is_up = true;
854 
855 	for (i = 0; i < nt->qp_count; i++) {
856 		struct ntb_transport_qp *qp = &nt->qp_vec[i];
857 
858 		ntb_transport_setup_qp_mw(nt, i);
859 
860 		if (qp->client_ready)
861 			schedule_delayed_work(&qp->link_work, 0);
862 	}
863 
864 	return;
865 
866 out1:
867 	for (i = 0; i < nt->mw_count; i++)
868 		ntb_free_mw(nt, i);
869 out:
870 	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
871 		schedule_delayed_work(&nt->link_work,
872 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
873 }
874 
875 static void ntb_qp_link_work(struct work_struct *work)
876 {
877 	struct ntb_transport_qp *qp = container_of(work,
878 						   struct ntb_transport_qp,
879 						   link_work.work);
880 	struct pci_dev *pdev = qp->ndev->pdev;
881 	struct ntb_transport_ctx *nt = qp->transport;
882 	int val;
883 
884 	WARN_ON(!nt->link_is_up);
885 
886 	val = ntb_spad_read(nt->ndev, QP_LINKS);
887 
888 	ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
889 
890 	/* query remote spad for qp ready bits */
891 	ntb_peer_spad_read(nt->ndev, QP_LINKS);
892 	dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
893 
894 	/* See if the remote side is up */
895 	if (val & BIT(qp->qp_num)) {
896 		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
897 		qp->link_is_up = true;
898 
899 		if (qp->event_handler)
900 			qp->event_handler(qp->cb_data, qp->link_is_up);
901 
902 		tasklet_schedule(&qp->rxc_db_work);
903 	} else if (nt->link_is_up)
904 		schedule_delayed_work(&qp->link_work,
905 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
906 }
907 
908 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
909 				    unsigned int qp_num)
910 {
911 	struct ntb_transport_qp *qp;
912 	struct ntb_transport_mw *mw;
913 	phys_addr_t mw_base;
914 	resource_size_t mw_size;
915 	unsigned int num_qps_mw, tx_size;
916 	unsigned int mw_num, mw_count, qp_count;
917 	u64 qp_offset;
918 
919 	mw_count = nt->mw_count;
920 	qp_count = nt->qp_count;
921 
922 	mw_num = QP_TO_MW(nt, qp_num);
923 	mw = &nt->mw_vec[mw_num];
924 
925 	qp = &nt->qp_vec[qp_num];
926 	qp->qp_num = qp_num;
927 	qp->transport = nt;
928 	qp->ndev = nt->ndev;
929 	qp->client_ready = false;
930 	qp->event_handler = NULL;
931 	ntb_qp_link_down_reset(qp);
932 
933 	if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
934 		num_qps_mw = qp_count / mw_count + 1;
935 	else
936 		num_qps_mw = qp_count / mw_count;
937 
938 	mw_base = nt->mw_vec[mw_num].phys_addr;
939 	mw_size = nt->mw_vec[mw_num].phys_size;
940 
941 	tx_size = (unsigned int)mw_size / num_qps_mw;
942 	qp_offset = tx_size * qp_num / mw_count;
943 
944 	qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
945 	if (!qp->tx_mw)
946 		return -EINVAL;
947 
948 	qp->tx_mw_phys = mw_base + qp_offset;
949 	if (!qp->tx_mw_phys)
950 		return -EINVAL;
951 
952 	tx_size -= sizeof(struct ntb_rx_info);
953 	qp->rx_info = qp->tx_mw + tx_size;
954 
955 	/* Due to housekeeping, there must be atleast 2 buffs */
956 	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
957 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
958 
959 	if (nt->debugfs_node_dir) {
960 		char debugfs_name[4];
961 
962 		snprintf(debugfs_name, 4, "qp%d", qp_num);
963 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
964 						     nt->debugfs_node_dir);
965 
966 		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
967 							qp->debugfs_dir, qp,
968 							&ntb_qp_debugfs_stats);
969 	} else {
970 		qp->debugfs_dir = NULL;
971 		qp->debugfs_stats = NULL;
972 	}
973 
974 	INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
975 	INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
976 
977 	spin_lock_init(&qp->ntb_rx_q_lock);
978 	spin_lock_init(&qp->ntb_tx_free_q_lock);
979 
980 	INIT_LIST_HEAD(&qp->rx_post_q);
981 	INIT_LIST_HEAD(&qp->rx_pend_q);
982 	INIT_LIST_HEAD(&qp->rx_free_q);
983 	INIT_LIST_HEAD(&qp->tx_free_q);
984 
985 	tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
986 		     (unsigned long)qp);
987 
988 	return 0;
989 }
990 
991 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
992 {
993 	struct ntb_transport_ctx *nt;
994 	struct ntb_transport_mw *mw;
995 	unsigned int mw_count, qp_count;
996 	u64 qp_bitmap;
997 	int node;
998 	int rc, i;
999 
1000 	if (ntb_db_is_unsafe(ndev))
1001 		dev_dbg(&ndev->dev,
1002 			"doorbell is unsafe, proceed anyway...\n");
1003 	if (ntb_spad_is_unsafe(ndev))
1004 		dev_dbg(&ndev->dev,
1005 			"scratchpad is unsafe, proceed anyway...\n");
1006 
1007 	node = dev_to_node(&ndev->dev);
1008 
1009 	nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1010 	if (!nt)
1011 		return -ENOMEM;
1012 
1013 	nt->ndev = ndev;
1014 
1015 	mw_count = ntb_mw_count(ndev);
1016 
1017 	nt->mw_count = mw_count;
1018 
1019 	nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
1020 				  GFP_KERNEL, node);
1021 	if (!nt->mw_vec) {
1022 		rc = -ENOMEM;
1023 		goto err;
1024 	}
1025 
1026 	for (i = 0; i < mw_count; i++) {
1027 		mw = &nt->mw_vec[i];
1028 
1029 		rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
1030 				      &mw->xlat_align, &mw->xlat_align_size);
1031 		if (rc)
1032 			goto err1;
1033 
1034 		mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1035 		if (!mw->vbase) {
1036 			rc = -ENOMEM;
1037 			goto err1;
1038 		}
1039 
1040 		mw->buff_size = 0;
1041 		mw->xlat_size = 0;
1042 		mw->virt_addr = NULL;
1043 		mw->dma_addr = 0;
1044 	}
1045 
1046 	qp_bitmap = ntb_db_valid_mask(ndev);
1047 
1048 	qp_count = ilog2(qp_bitmap);
1049 	if (max_num_clients && max_num_clients < qp_count)
1050 		qp_count = max_num_clients;
1051 	else if (mw_count < qp_count)
1052 		qp_count = mw_count;
1053 
1054 	qp_bitmap &= BIT_ULL(qp_count) - 1;
1055 
1056 	nt->qp_count = qp_count;
1057 	nt->qp_bitmap = qp_bitmap;
1058 	nt->qp_bitmap_free = qp_bitmap;
1059 
1060 	nt->qp_vec = kzalloc_node(qp_count * sizeof(*nt->qp_vec),
1061 				  GFP_KERNEL, node);
1062 	if (!nt->qp_vec) {
1063 		rc = -ENOMEM;
1064 		goto err2;
1065 	}
1066 
1067 	if (nt_debugfs_dir) {
1068 		nt->debugfs_node_dir =
1069 			debugfs_create_dir(pci_name(ndev->pdev),
1070 					   nt_debugfs_dir);
1071 	}
1072 
1073 	for (i = 0; i < qp_count; i++) {
1074 		rc = ntb_transport_init_queue(nt, i);
1075 		if (rc)
1076 			goto err3;
1077 	}
1078 
1079 	INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1080 	INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1081 
1082 	rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1083 	if (rc)
1084 		goto err3;
1085 
1086 	INIT_LIST_HEAD(&nt->client_devs);
1087 	rc = ntb_bus_init(nt);
1088 	if (rc)
1089 		goto err4;
1090 
1091 	nt->link_is_up = false;
1092 	ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1093 	ntb_link_event(ndev);
1094 
1095 	return 0;
1096 
1097 err4:
1098 	ntb_clear_ctx(ndev);
1099 err3:
1100 	kfree(nt->qp_vec);
1101 err2:
1102 	kfree(nt->mw_vec);
1103 err1:
1104 	while (i--) {
1105 		mw = &nt->mw_vec[i];
1106 		iounmap(mw->vbase);
1107 	}
1108 err:
1109 	kfree(nt);
1110 	return rc;
1111 }
1112 
1113 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1114 {
1115 	struct ntb_transport_ctx *nt = ndev->ctx;
1116 	struct ntb_transport_qp *qp;
1117 	u64 qp_bitmap_alloc;
1118 	int i;
1119 
1120 	ntb_transport_link_cleanup(nt);
1121 	cancel_work_sync(&nt->link_cleanup);
1122 	cancel_delayed_work_sync(&nt->link_work);
1123 
1124 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1125 
1126 	/* verify that all the qp's are freed */
1127 	for (i = 0; i < nt->qp_count; i++) {
1128 		qp = &nt->qp_vec[i];
1129 		if (qp_bitmap_alloc & BIT_ULL(i))
1130 			ntb_transport_free_queue(qp);
1131 		debugfs_remove_recursive(qp->debugfs_dir);
1132 	}
1133 
1134 	ntb_link_disable(ndev);
1135 	ntb_clear_ctx(ndev);
1136 
1137 	ntb_bus_remove(nt);
1138 
1139 	for (i = nt->mw_count; i--; ) {
1140 		ntb_free_mw(nt, i);
1141 		iounmap(nt->mw_vec[i].vbase);
1142 	}
1143 
1144 	kfree(nt->qp_vec);
1145 	kfree(nt->mw_vec);
1146 	kfree(nt);
1147 }
1148 
1149 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1150 {
1151 	struct ntb_queue_entry *entry;
1152 	void *cb_data;
1153 	unsigned int len;
1154 	unsigned long irqflags;
1155 
1156 	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1157 
1158 	while (!list_empty(&qp->rx_post_q)) {
1159 		entry = list_first_entry(&qp->rx_post_q,
1160 					 struct ntb_queue_entry, entry);
1161 		if (!(entry->flags & DESC_DONE_FLAG))
1162 			break;
1163 
1164 		entry->rx_hdr->flags = 0;
1165 		iowrite32(entry->index, &qp->rx_info->entry);
1166 
1167 		cb_data = entry->cb_data;
1168 		len = entry->len;
1169 
1170 		list_move_tail(&entry->entry, &qp->rx_free_q);
1171 
1172 		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1173 
1174 		if (qp->rx_handler && qp->client_ready)
1175 			qp->rx_handler(qp, qp->cb_data, cb_data, len);
1176 
1177 		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1178 	}
1179 
1180 	spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1181 }
1182 
1183 static void ntb_rx_copy_callback(void *data)
1184 {
1185 	struct ntb_queue_entry *entry = data;
1186 
1187 	entry->flags |= DESC_DONE_FLAG;
1188 
1189 	ntb_complete_rxc(entry->qp);
1190 }
1191 
1192 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1193 {
1194 	void *buf = entry->buf;
1195 	size_t len = entry->len;
1196 
1197 	memcpy(buf, offset, len);
1198 
1199 	/* Ensure that the data is fully copied out before clearing the flag */
1200 	wmb();
1201 
1202 	ntb_rx_copy_callback(entry);
1203 }
1204 
1205 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1206 {
1207 	struct dma_async_tx_descriptor *txd;
1208 	struct ntb_transport_qp *qp = entry->qp;
1209 	struct dma_chan *chan = qp->dma_chan;
1210 	struct dma_device *device;
1211 	size_t pay_off, buff_off, len;
1212 	struct dmaengine_unmap_data *unmap;
1213 	dma_cookie_t cookie;
1214 	void *buf = entry->buf;
1215 
1216 	len = entry->len;
1217 
1218 	if (!chan)
1219 		goto err;
1220 
1221 	if (len < copy_bytes)
1222 		goto err_wait;
1223 
1224 	device = chan->device;
1225 	pay_off = (size_t)offset & ~PAGE_MASK;
1226 	buff_off = (size_t)buf & ~PAGE_MASK;
1227 
1228 	if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1229 		goto err_wait;
1230 
1231 	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1232 	if (!unmap)
1233 		goto err_wait;
1234 
1235 	unmap->len = len;
1236 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1237 				      pay_off, len, DMA_TO_DEVICE);
1238 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1239 		goto err_get_unmap;
1240 
1241 	unmap->to_cnt = 1;
1242 
1243 	unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1244 				      buff_off, len, DMA_FROM_DEVICE);
1245 	if (dma_mapping_error(device->dev, unmap->addr[1]))
1246 		goto err_get_unmap;
1247 
1248 	unmap->from_cnt = 1;
1249 
1250 	txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1251 					     unmap->addr[0], len,
1252 					     DMA_PREP_INTERRUPT);
1253 	if (!txd)
1254 		goto err_get_unmap;
1255 
1256 	txd->callback = ntb_rx_copy_callback;
1257 	txd->callback_param = entry;
1258 	dma_set_unmap(txd, unmap);
1259 
1260 	cookie = dmaengine_submit(txd);
1261 	if (dma_submit_error(cookie))
1262 		goto err_set_unmap;
1263 
1264 	dmaengine_unmap_put(unmap);
1265 
1266 	qp->last_cookie = cookie;
1267 
1268 	qp->rx_async++;
1269 
1270 	return;
1271 
1272 err_set_unmap:
1273 	dmaengine_unmap_put(unmap);
1274 err_get_unmap:
1275 	dmaengine_unmap_put(unmap);
1276 err_wait:
1277 	/* If the callbacks come out of order, the writing of the index to the
1278 	 * last completed will be out of order.  This may result in the
1279 	 * receive stalling forever.
1280 	 */
1281 	dma_sync_wait(chan, qp->last_cookie);
1282 err:
1283 	ntb_memcpy_rx(entry, offset);
1284 	qp->rx_memcpy++;
1285 }
1286 
1287 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1288 {
1289 	struct ntb_payload_header *hdr;
1290 	struct ntb_queue_entry *entry;
1291 	void *offset;
1292 
1293 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1294 	hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1295 
1296 	dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1297 		qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1298 
1299 	if (!(hdr->flags & DESC_DONE_FLAG)) {
1300 		dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1301 		qp->rx_ring_empty++;
1302 		return -EAGAIN;
1303 	}
1304 
1305 	if (hdr->flags & LINK_DOWN_FLAG) {
1306 		dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1307 		ntb_qp_link_down(qp);
1308 		hdr->flags = 0;
1309 		return -EAGAIN;
1310 	}
1311 
1312 	if (hdr->ver != (u32)qp->rx_pkts) {
1313 		dev_dbg(&qp->ndev->pdev->dev,
1314 			"version mismatch, expected %llu - got %u\n",
1315 			qp->rx_pkts, hdr->ver);
1316 		qp->rx_err_ver++;
1317 		return -EIO;
1318 	}
1319 
1320 	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1321 	if (!entry) {
1322 		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1323 		qp->rx_err_no_buf++;
1324 		return -EAGAIN;
1325 	}
1326 
1327 	entry->rx_hdr = hdr;
1328 	entry->index = qp->rx_index;
1329 
1330 	if (hdr->len > entry->len) {
1331 		dev_dbg(&qp->ndev->pdev->dev,
1332 			"receive buffer overflow! Wanted %d got %d\n",
1333 			hdr->len, entry->len);
1334 		qp->rx_err_oflow++;
1335 
1336 		entry->len = -EIO;
1337 		entry->flags |= DESC_DONE_FLAG;
1338 
1339 		ntb_complete_rxc(qp);
1340 	} else {
1341 		dev_dbg(&qp->ndev->pdev->dev,
1342 			"RX OK index %u ver %u size %d into buf size %d\n",
1343 			qp->rx_index, hdr->ver, hdr->len, entry->len);
1344 
1345 		qp->rx_bytes += hdr->len;
1346 		qp->rx_pkts++;
1347 
1348 		entry->len = hdr->len;
1349 
1350 		ntb_async_rx(entry, offset);
1351 	}
1352 
1353 	qp->rx_index++;
1354 	qp->rx_index %= qp->rx_max_entry;
1355 
1356 	return 0;
1357 }
1358 
1359 static void ntb_transport_rxc_db(unsigned long data)
1360 {
1361 	struct ntb_transport_qp *qp = (void *)data;
1362 	int rc, i;
1363 
1364 	dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1365 		__func__, qp->qp_num);
1366 
1367 	/* Limit the number of packets processed in a single interrupt to
1368 	 * provide fairness to others
1369 	 */
1370 	for (i = 0; i < qp->rx_max_entry; i++) {
1371 		rc = ntb_process_rxc(qp);
1372 		if (rc)
1373 			break;
1374 	}
1375 
1376 	if (i && qp->dma_chan)
1377 		dma_async_issue_pending(qp->dma_chan);
1378 
1379 	if (i == qp->rx_max_entry) {
1380 		/* there is more work to do */
1381 		tasklet_schedule(&qp->rxc_db_work);
1382 	} else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1383 		/* the doorbell bit is set: clear it */
1384 		ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1385 		/* ntb_db_read ensures ntb_db_clear write is committed */
1386 		ntb_db_read(qp->ndev);
1387 
1388 		/* an interrupt may have arrived between finishing
1389 		 * ntb_process_rxc and clearing the doorbell bit:
1390 		 * there might be some more work to do.
1391 		 */
1392 		tasklet_schedule(&qp->rxc_db_work);
1393 	}
1394 }
1395 
1396 static void ntb_tx_copy_callback(void *data)
1397 {
1398 	struct ntb_queue_entry *entry = data;
1399 	struct ntb_transport_qp *qp = entry->qp;
1400 	struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1401 
1402 	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1403 
1404 	ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1405 
1406 	/* The entry length can only be zero if the packet is intended to be a
1407 	 * "link down" or similar.  Since no payload is being sent in these
1408 	 * cases, there is nothing to add to the completion queue.
1409 	 */
1410 	if (entry->len > 0) {
1411 		qp->tx_bytes += entry->len;
1412 
1413 		if (qp->tx_handler)
1414 			qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1415 				       entry->len);
1416 	}
1417 
1418 	ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1419 }
1420 
1421 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1422 {
1423 #ifdef ARCH_HAS_NOCACHE_UACCESS
1424 	/*
1425 	 * Using non-temporal mov to improve performance on non-cached
1426 	 * writes, even though we aren't actually copying from user space.
1427 	 */
1428 	__copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1429 #else
1430 	memcpy_toio(offset, entry->buf, entry->len);
1431 #endif
1432 
1433 	/* Ensure that the data is fully copied out before setting the flags */
1434 	wmb();
1435 
1436 	ntb_tx_copy_callback(entry);
1437 }
1438 
1439 static void ntb_async_tx(struct ntb_transport_qp *qp,
1440 			 struct ntb_queue_entry *entry)
1441 {
1442 	struct ntb_payload_header __iomem *hdr;
1443 	struct dma_async_tx_descriptor *txd;
1444 	struct dma_chan *chan = qp->dma_chan;
1445 	struct dma_device *device;
1446 	size_t dest_off, buff_off;
1447 	struct dmaengine_unmap_data *unmap;
1448 	dma_addr_t dest;
1449 	dma_cookie_t cookie;
1450 	void __iomem *offset;
1451 	size_t len = entry->len;
1452 	void *buf = entry->buf;
1453 
1454 	offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1455 	hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1456 	entry->tx_hdr = hdr;
1457 
1458 	iowrite32(entry->len, &hdr->len);
1459 	iowrite32((u32)qp->tx_pkts, &hdr->ver);
1460 
1461 	if (!chan)
1462 		goto err;
1463 
1464 	if (len < copy_bytes)
1465 		goto err;
1466 
1467 	device = chan->device;
1468 	dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1469 	buff_off = (size_t)buf & ~PAGE_MASK;
1470 	dest_off = (size_t)dest & ~PAGE_MASK;
1471 
1472 	if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1473 		goto err;
1474 
1475 	unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1476 	if (!unmap)
1477 		goto err;
1478 
1479 	unmap->len = len;
1480 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1481 				      buff_off, len, DMA_TO_DEVICE);
1482 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1483 		goto err_get_unmap;
1484 
1485 	unmap->to_cnt = 1;
1486 
1487 	txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1488 					     DMA_PREP_INTERRUPT);
1489 	if (!txd)
1490 		goto err_get_unmap;
1491 
1492 	txd->callback = ntb_tx_copy_callback;
1493 	txd->callback_param = entry;
1494 	dma_set_unmap(txd, unmap);
1495 
1496 	cookie = dmaengine_submit(txd);
1497 	if (dma_submit_error(cookie))
1498 		goto err_set_unmap;
1499 
1500 	dmaengine_unmap_put(unmap);
1501 
1502 	dma_async_issue_pending(chan);
1503 	qp->tx_async++;
1504 
1505 	return;
1506 err_set_unmap:
1507 	dmaengine_unmap_put(unmap);
1508 err_get_unmap:
1509 	dmaengine_unmap_put(unmap);
1510 err:
1511 	ntb_memcpy_tx(entry, offset);
1512 	qp->tx_memcpy++;
1513 }
1514 
1515 static int ntb_process_tx(struct ntb_transport_qp *qp,
1516 			  struct ntb_queue_entry *entry)
1517 {
1518 	if (qp->tx_index == qp->remote_rx_info->entry) {
1519 		qp->tx_ring_full++;
1520 		return -EAGAIN;
1521 	}
1522 
1523 	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1524 		if (qp->tx_handler)
1525 			qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1526 
1527 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1528 			     &qp->tx_free_q);
1529 		return 0;
1530 	}
1531 
1532 	ntb_async_tx(qp, entry);
1533 
1534 	qp->tx_index++;
1535 	qp->tx_index %= qp->tx_max_entry;
1536 
1537 	qp->tx_pkts++;
1538 
1539 	return 0;
1540 }
1541 
1542 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1543 {
1544 	struct pci_dev *pdev = qp->ndev->pdev;
1545 	struct ntb_queue_entry *entry;
1546 	int i, rc;
1547 
1548 	if (!qp->link_is_up)
1549 		return;
1550 
1551 	dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1552 
1553 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1554 		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1555 		if (entry)
1556 			break;
1557 		msleep(100);
1558 	}
1559 
1560 	if (!entry)
1561 		return;
1562 
1563 	entry->cb_data = NULL;
1564 	entry->buf = NULL;
1565 	entry->len = 0;
1566 	entry->flags = LINK_DOWN_FLAG;
1567 
1568 	rc = ntb_process_tx(qp, entry);
1569 	if (rc)
1570 		dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1571 			qp->qp_num);
1572 
1573 	ntb_qp_link_down_reset(qp);
1574 }
1575 
1576 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1577 {
1578 	return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1579 }
1580 
1581 /**
1582  * ntb_transport_create_queue - Create a new NTB transport layer queue
1583  * @rx_handler: receive callback function
1584  * @tx_handler: transmit callback function
1585  * @event_handler: event callback function
1586  *
1587  * Create a new NTB transport layer queue and provide the queue with a callback
1588  * routine for both transmit and receive.  The receive callback routine will be
1589  * used to pass up data when the transport has received it on the queue.   The
1590  * transmit callback routine will be called when the transport has completed the
1591  * transmission of the data on the queue and the data is ready to be freed.
1592  *
1593  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1594  */
1595 struct ntb_transport_qp *
1596 ntb_transport_create_queue(void *data, struct device *client_dev,
1597 			   const struct ntb_queue_handlers *handlers)
1598 {
1599 	struct ntb_dev *ndev;
1600 	struct pci_dev *pdev;
1601 	struct ntb_transport_ctx *nt;
1602 	struct ntb_queue_entry *entry;
1603 	struct ntb_transport_qp *qp;
1604 	u64 qp_bit;
1605 	unsigned int free_queue;
1606 	dma_cap_mask_t dma_mask;
1607 	int node;
1608 	int i;
1609 
1610 	ndev = dev_ntb(client_dev->parent);
1611 	pdev = ndev->pdev;
1612 	nt = ndev->ctx;
1613 
1614 	node = dev_to_node(&ndev->dev);
1615 
1616 	free_queue = ffs(nt->qp_bitmap);
1617 	if (!free_queue)
1618 		goto err;
1619 
1620 	/* decrement free_queue to make it zero based */
1621 	free_queue--;
1622 
1623 	qp = &nt->qp_vec[free_queue];
1624 	qp_bit = BIT_ULL(qp->qp_num);
1625 
1626 	nt->qp_bitmap_free &= ~qp_bit;
1627 
1628 	qp->cb_data = data;
1629 	qp->rx_handler = handlers->rx_handler;
1630 	qp->tx_handler = handlers->tx_handler;
1631 	qp->event_handler = handlers->event_handler;
1632 
1633 	dma_cap_zero(dma_mask);
1634 	dma_cap_set(DMA_MEMCPY, dma_mask);
1635 
1636 	if (use_dma) {
1637 		qp->dma_chan = dma_request_channel(dma_mask, ntb_dma_filter_fn,
1638 						   (void *)(unsigned long)node);
1639 		if (!qp->dma_chan)
1640 			dev_info(&pdev->dev, "Unable to allocate DMA channel\n");
1641 	} else {
1642 		qp->dma_chan = NULL;
1643 	}
1644 	dev_dbg(&pdev->dev, "Using %s memcpy\n", qp->dma_chan ? "DMA" : "CPU");
1645 
1646 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1647 		entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1648 		if (!entry)
1649 			goto err1;
1650 
1651 		entry->qp = qp;
1652 		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
1653 			     &qp->rx_free_q);
1654 	}
1655 
1656 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1657 		entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1658 		if (!entry)
1659 			goto err2;
1660 
1661 		entry->qp = qp;
1662 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1663 			     &qp->tx_free_q);
1664 	}
1665 
1666 	ntb_db_clear(qp->ndev, qp_bit);
1667 	ntb_db_clear_mask(qp->ndev, qp_bit);
1668 
1669 	dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1670 
1671 	return qp;
1672 
1673 err2:
1674 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1675 		kfree(entry);
1676 err1:
1677 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1678 		kfree(entry);
1679 	if (qp->dma_chan)
1680 		dma_release_channel(qp->dma_chan);
1681 	nt->qp_bitmap_free |= qp_bit;
1682 err:
1683 	return NULL;
1684 }
1685 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1686 
1687 /**
1688  * ntb_transport_free_queue - Frees NTB transport queue
1689  * @qp: NTB queue to be freed
1690  *
1691  * Frees NTB transport queue
1692  */
1693 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1694 {
1695 	struct pci_dev *pdev;
1696 	struct ntb_queue_entry *entry;
1697 	u64 qp_bit;
1698 
1699 	if (!qp)
1700 		return;
1701 
1702 	pdev = qp->ndev->pdev;
1703 
1704 	if (qp->dma_chan) {
1705 		struct dma_chan *chan = qp->dma_chan;
1706 		/* Putting the dma_chan to NULL will force any new traffic to be
1707 		 * processed by the CPU instead of the DAM engine
1708 		 */
1709 		qp->dma_chan = NULL;
1710 
1711 		/* Try to be nice and wait for any queued DMA engine
1712 		 * transactions to process before smashing it with a rock
1713 		 */
1714 		dma_sync_wait(chan, qp->last_cookie);
1715 		dmaengine_terminate_all(chan);
1716 		dma_release_channel(chan);
1717 	}
1718 
1719 	qp_bit = BIT_ULL(qp->qp_num);
1720 
1721 	ntb_db_set_mask(qp->ndev, qp_bit);
1722 	tasklet_disable(&qp->rxc_db_work);
1723 
1724 	cancel_delayed_work_sync(&qp->link_work);
1725 
1726 	qp->cb_data = NULL;
1727 	qp->rx_handler = NULL;
1728 	qp->tx_handler = NULL;
1729 	qp->event_handler = NULL;
1730 
1731 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1732 		kfree(entry);
1733 
1734 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
1735 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
1736 		kfree(entry);
1737 	}
1738 
1739 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
1740 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
1741 		kfree(entry);
1742 	}
1743 
1744 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1745 		kfree(entry);
1746 
1747 	qp->transport->qp_bitmap_free |= qp_bit;
1748 
1749 	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1750 }
1751 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1752 
1753 /**
1754  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1755  * @qp: NTB queue to be freed
1756  * @len: pointer to variable to write enqueued buffers length
1757  *
1758  * Dequeues unused buffers from receive queue.  Should only be used during
1759  * shutdown of qp.
1760  *
1761  * RETURNS: NULL error value on error, or void* for success.
1762  */
1763 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1764 {
1765 	struct ntb_queue_entry *entry;
1766 	void *buf;
1767 
1768 	if (!qp || qp->client_ready)
1769 		return NULL;
1770 
1771 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
1772 	if (!entry)
1773 		return NULL;
1774 
1775 	buf = entry->cb_data;
1776 	*len = entry->len;
1777 
1778 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
1779 
1780 	return buf;
1781 }
1782 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1783 
1784 /**
1785  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1786  * @qp: NTB transport layer queue the entry is to be enqueued on
1787  * @cb: per buffer pointer for callback function to use
1788  * @data: pointer to data buffer that incoming packets will be copied into
1789  * @len: length of the data buffer
1790  *
1791  * Enqueue a new receive buffer onto the transport queue into which a NTB
1792  * payload can be received into.
1793  *
1794  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1795  */
1796 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1797 			     unsigned int len)
1798 {
1799 	struct ntb_queue_entry *entry;
1800 
1801 	if (!qp)
1802 		return -EINVAL;
1803 
1804 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
1805 	if (!entry)
1806 		return -ENOMEM;
1807 
1808 	entry->cb_data = cb;
1809 	entry->buf = data;
1810 	entry->len = len;
1811 	entry->flags = 0;
1812 
1813 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
1814 
1815 	tasklet_schedule(&qp->rxc_db_work);
1816 
1817 	return 0;
1818 }
1819 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1820 
1821 /**
1822  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1823  * @qp: NTB transport layer queue the entry is to be enqueued on
1824  * @cb: per buffer pointer for callback function to use
1825  * @data: pointer to data buffer that will be sent
1826  * @len: length of the data buffer
1827  *
1828  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1829  * payload will be transmitted.  This assumes that a lock is being held to
1830  * serialize access to the qp.
1831  *
1832  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1833  */
1834 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1835 			     unsigned int len)
1836 {
1837 	struct ntb_queue_entry *entry;
1838 	int rc;
1839 
1840 	if (!qp || !qp->link_is_up || !len)
1841 		return -EINVAL;
1842 
1843 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1844 	if (!entry) {
1845 		qp->tx_err_no_buf++;
1846 		return -ENOMEM;
1847 	}
1848 
1849 	entry->cb_data = cb;
1850 	entry->buf = data;
1851 	entry->len = len;
1852 	entry->flags = 0;
1853 
1854 	rc = ntb_process_tx(qp, entry);
1855 	if (rc)
1856 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1857 			     &qp->tx_free_q);
1858 
1859 	return rc;
1860 }
1861 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1862 
1863 /**
1864  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1865  * @qp: NTB transport layer queue to be enabled
1866  *
1867  * Notify NTB transport layer of client readiness to use queue
1868  */
1869 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1870 {
1871 	if (!qp)
1872 		return;
1873 
1874 	qp->client_ready = true;
1875 
1876 	if (qp->transport->link_is_up)
1877 		schedule_delayed_work(&qp->link_work, 0);
1878 }
1879 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1880 
1881 /**
1882  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1883  * @qp: NTB transport layer queue to be disabled
1884  *
1885  * Notify NTB transport layer of client's desire to no longer receive data on
1886  * transport queue specified.  It is the client's responsibility to ensure all
1887  * entries on queue are purged or otherwise handled appropriately.
1888  */
1889 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1890 {
1891 	struct pci_dev *pdev;
1892 	int val;
1893 
1894 	if (!qp)
1895 		return;
1896 
1897 	pdev = qp->ndev->pdev;
1898 	qp->client_ready = false;
1899 
1900 	val = ntb_spad_read(qp->ndev, QP_LINKS);
1901 
1902 	ntb_peer_spad_write(qp->ndev, QP_LINKS,
1903 			    val & ~BIT(qp->qp_num));
1904 
1905 	if (qp->link_is_up)
1906 		ntb_send_link_down(qp);
1907 	else
1908 		cancel_delayed_work_sync(&qp->link_work);
1909 }
1910 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1911 
1912 /**
1913  * ntb_transport_link_query - Query transport link state
1914  * @qp: NTB transport layer queue to be queried
1915  *
1916  * Query connectivity to the remote system of the NTB transport queue
1917  *
1918  * RETURNS: true for link up or false for link down
1919  */
1920 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1921 {
1922 	if (!qp)
1923 		return false;
1924 
1925 	return qp->link_is_up;
1926 }
1927 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1928 
1929 /**
1930  * ntb_transport_qp_num - Query the qp number
1931  * @qp: NTB transport layer queue to be queried
1932  *
1933  * Query qp number of the NTB transport queue
1934  *
1935  * RETURNS: a zero based number specifying the qp number
1936  */
1937 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1938 {
1939 	if (!qp)
1940 		return 0;
1941 
1942 	return qp->qp_num;
1943 }
1944 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1945 
1946 /**
1947  * ntb_transport_max_size - Query the max payload size of a qp
1948  * @qp: NTB transport layer queue to be queried
1949  *
1950  * Query the maximum payload size permissible on the given qp
1951  *
1952  * RETURNS: the max payload size of a qp
1953  */
1954 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1955 {
1956 	unsigned int max;
1957 
1958 	if (!qp)
1959 		return 0;
1960 
1961 	if (!qp->dma_chan)
1962 		return qp->tx_max_frame - sizeof(struct ntb_payload_header);
1963 
1964 	/* If DMA engine usage is possible, try to find the max size for that */
1965 	max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
1966 	max -= max % (1 << qp->dma_chan->device->copy_align);
1967 
1968 	return max;
1969 }
1970 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
1971 
1972 static void ntb_transport_doorbell_callback(void *data, int vector)
1973 {
1974 	struct ntb_transport_ctx *nt = data;
1975 	struct ntb_transport_qp *qp;
1976 	u64 db_bits;
1977 	unsigned int qp_num;
1978 
1979 	db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
1980 		   ntb_db_vector_mask(nt->ndev, vector));
1981 
1982 	while (db_bits) {
1983 		qp_num = __ffs(db_bits);
1984 		qp = &nt->qp_vec[qp_num];
1985 
1986 		tasklet_schedule(&qp->rxc_db_work);
1987 
1988 		db_bits &= ~BIT_ULL(qp_num);
1989 	}
1990 }
1991 
1992 static const struct ntb_ctx_ops ntb_transport_ops = {
1993 	.link_event = ntb_transport_event_callback,
1994 	.db_event = ntb_transport_doorbell_callback,
1995 };
1996 
1997 static struct ntb_client ntb_transport_client = {
1998 	.ops = {
1999 		.probe = ntb_transport_probe,
2000 		.remove = ntb_transport_free,
2001 	},
2002 };
2003 
2004 static int __init ntb_transport_init(void)
2005 {
2006 	int rc;
2007 
2008 	pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2009 
2010 	if (debugfs_initialized())
2011 		nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2012 
2013 	rc = bus_register(&ntb_transport_bus);
2014 	if (rc)
2015 		goto err_bus;
2016 
2017 	rc = ntb_register_client(&ntb_transport_client);
2018 	if (rc)
2019 		goto err_client;
2020 
2021 	return 0;
2022 
2023 err_client:
2024 	bus_unregister(&ntb_transport_bus);
2025 err_bus:
2026 	debugfs_remove_recursive(nt_debugfs_dir);
2027 	return rc;
2028 }
2029 module_init(ntb_transport_init);
2030 
2031 static void __exit ntb_transport_exit(void)
2032 {
2033 	debugfs_remove_recursive(nt_debugfs_dir);
2034 
2035 	ntb_unregister_client(&ntb_transport_client);
2036 	bus_unregister(&ntb_transport_bus);
2037 }
2038 module_exit(ntb_transport_exit);
2039