xref: /linux/drivers/ntb/ntb_transport.c (revision f7af616c632ee2ac3af0876fe33bf9e0232e665a)
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 #define NTB_TRANSPORT_MIN_SPADS (MW0_SZ_HIGH + 2)
70 
71 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
72 MODULE_VERSION(NTB_TRANSPORT_VER);
73 MODULE_LICENSE("Dual BSD/GPL");
74 MODULE_AUTHOR("Intel Corporation");
75 
76 static unsigned long max_mw_size;
77 module_param(max_mw_size, ulong, 0644);
78 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
79 
80 static unsigned int transport_mtu = 0x10000;
81 module_param(transport_mtu, uint, 0644);
82 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
83 
84 static unsigned char max_num_clients;
85 module_param(max_num_clients, byte, 0644);
86 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
87 
88 static unsigned int copy_bytes = 1024;
89 module_param(copy_bytes, uint, 0644);
90 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
91 
92 static bool use_dma;
93 module_param(use_dma, bool, 0644);
94 MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
95 
96 static bool use_msi;
97 #ifdef CONFIG_NTB_MSI
98 module_param(use_msi, bool, 0644);
99 MODULE_PARM_DESC(use_msi, "Use MSI interrupts instead of doorbells");
100 #endif
101 
102 static struct dentry *nt_debugfs_dir;
103 
104 /* Only two-ports NTB devices are supported */
105 #define PIDX		NTB_DEF_PEER_IDX
106 
107 struct ntb_queue_entry {
108 	/* ntb_queue list reference */
109 	struct list_head entry;
110 	/* pointers to data to be transferred */
111 	void *cb_data;
112 	void *buf;
113 	unsigned int len;
114 	unsigned int flags;
115 	int retries;
116 	int errors;
117 	unsigned int tx_index;
118 	unsigned int rx_index;
119 
120 	struct ntb_transport_qp *qp;
121 	union {
122 		struct ntb_payload_header __iomem *tx_hdr;
123 		struct ntb_payload_header *rx_hdr;
124 	};
125 };
126 
127 struct ntb_rx_info {
128 	unsigned int entry;
129 };
130 
131 struct ntb_transport_qp {
132 	struct ntb_transport_ctx *transport;
133 	struct ntb_dev *ndev;
134 	void *cb_data;
135 	struct dma_chan *tx_dma_chan;
136 	struct dma_chan *rx_dma_chan;
137 
138 	bool client_ready;
139 	bool link_is_up;
140 	bool active;
141 
142 	u8 qp_num;	/* Only 64 QP's are allowed.  0-63 */
143 	u64 qp_bit;
144 
145 	struct ntb_rx_info __iomem *rx_info;
146 	struct ntb_rx_info *remote_rx_info;
147 
148 	void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
149 			   void *data, int len);
150 	struct list_head tx_free_q;
151 	spinlock_t ntb_tx_free_q_lock;
152 	void __iomem *tx_mw;
153 	phys_addr_t tx_mw_phys;
154 	size_t tx_mw_size;
155 	dma_addr_t tx_mw_dma_addr;
156 	unsigned int tx_index;
157 	unsigned int tx_max_entry;
158 	unsigned int tx_max_frame;
159 
160 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
161 			   void *data, int len);
162 	struct list_head rx_post_q;
163 	struct list_head rx_pend_q;
164 	struct list_head rx_free_q;
165 	/* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
166 	spinlock_t ntb_rx_q_lock;
167 	void *rx_buff;
168 	unsigned int rx_index;
169 	unsigned int rx_max_entry;
170 	unsigned int rx_max_frame;
171 	unsigned int rx_alloc_entry;
172 	dma_cookie_t last_cookie;
173 	struct tasklet_struct rxc_db_work;
174 
175 	void (*event_handler)(void *data, int status);
176 	struct delayed_work link_work;
177 	struct work_struct link_cleanup;
178 
179 	struct dentry *debugfs_dir;
180 	struct dentry *debugfs_stats;
181 
182 	/* Stats */
183 	u64 rx_bytes;
184 	u64 rx_pkts;
185 	u64 rx_ring_empty;
186 	u64 rx_err_no_buf;
187 	u64 rx_err_oflow;
188 	u64 rx_err_ver;
189 	u64 rx_memcpy;
190 	u64 rx_async;
191 	u64 tx_bytes;
192 	u64 tx_pkts;
193 	u64 tx_ring_full;
194 	u64 tx_err_no_buf;
195 	u64 tx_memcpy;
196 	u64 tx_async;
197 
198 	bool use_msi;
199 	int msi_irq;
200 	struct ntb_msi_desc msi_desc;
201 	struct ntb_msi_desc peer_msi_desc;
202 };
203 
204 struct ntb_transport_mw {
205 	phys_addr_t phys_addr;
206 	resource_size_t phys_size;
207 	void __iomem *vbase;
208 	size_t xlat_size;
209 	size_t buff_size;
210 	size_t alloc_size;
211 	void *alloc_addr;
212 	void *virt_addr;
213 	dma_addr_t dma_addr;
214 };
215 
216 struct ntb_transport_client_dev {
217 	struct list_head entry;
218 	struct ntb_transport_ctx *nt;
219 	struct device dev;
220 };
221 
222 struct ntb_transport_ctx {
223 	struct list_head entry;
224 	struct list_head client_devs;
225 
226 	struct ntb_dev *ndev;
227 
228 	struct ntb_transport_mw *mw_vec;
229 	struct ntb_transport_qp *qp_vec;
230 	unsigned int mw_count;
231 	unsigned int qp_count;
232 	u64 qp_bitmap;
233 	u64 qp_bitmap_free;
234 
235 	bool use_msi;
236 	unsigned int msi_spad_offset;
237 	u64 msi_db_mask;
238 
239 	bool link_is_up;
240 	struct delayed_work link_work;
241 	struct work_struct link_cleanup;
242 
243 	struct dentry *debugfs_node_dir;
244 };
245 
246 enum {
247 	DESC_DONE_FLAG = BIT(0),
248 	LINK_DOWN_FLAG = BIT(1),
249 };
250 
251 struct ntb_payload_header {
252 	unsigned int ver;
253 	unsigned int len;
254 	unsigned int flags;
255 };
256 
257 enum {
258 	VERSION = 0,
259 	QP_LINKS,
260 	NUM_QPS,
261 	NUM_MWS,
262 	MW0_SZ_HIGH,
263 	MW0_SZ_LOW,
264 };
265 
266 #define dev_client_dev(__dev) \
267 	container_of((__dev), struct ntb_transport_client_dev, dev)
268 
269 #define drv_client(__drv) \
270 	container_of((__drv), struct ntb_transport_client, driver)
271 
272 #define QP_TO_MW(nt, qp)	((qp) % nt->mw_count)
273 #define NTB_QP_DEF_NUM_ENTRIES	100
274 #define NTB_LINK_DOWN_TIMEOUT	10
275 
276 static void ntb_transport_rxc_db(unsigned long data);
277 static const struct ntb_ctx_ops ntb_transport_ops;
278 static struct ntb_client ntb_transport_client;
279 static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
280 			       struct ntb_queue_entry *entry);
281 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset);
282 static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset);
283 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset);
284 
285 
286 static int ntb_transport_bus_match(struct device *dev,
287 				   struct device_driver *drv)
288 {
289 	return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
290 }
291 
292 static int ntb_transport_bus_probe(struct device *dev)
293 {
294 	const struct ntb_transport_client *client;
295 	int rc;
296 
297 	get_device(dev);
298 
299 	client = drv_client(dev->driver);
300 	rc = client->probe(dev);
301 	if (rc)
302 		put_device(dev);
303 
304 	return rc;
305 }
306 
307 static int ntb_transport_bus_remove(struct device *dev)
308 {
309 	const struct ntb_transport_client *client;
310 
311 	client = drv_client(dev->driver);
312 	client->remove(dev);
313 
314 	put_device(dev);
315 
316 	return 0;
317 }
318 
319 static struct bus_type ntb_transport_bus = {
320 	.name = "ntb_transport",
321 	.match = ntb_transport_bus_match,
322 	.probe = ntb_transport_bus_probe,
323 	.remove = ntb_transport_bus_remove,
324 };
325 
326 static LIST_HEAD(ntb_transport_list);
327 
328 static int ntb_bus_init(struct ntb_transport_ctx *nt)
329 {
330 	list_add_tail(&nt->entry, &ntb_transport_list);
331 	return 0;
332 }
333 
334 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
335 {
336 	struct ntb_transport_client_dev *client_dev, *cd;
337 
338 	list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
339 		dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
340 			dev_name(&client_dev->dev));
341 		list_del(&client_dev->entry);
342 		device_unregister(&client_dev->dev);
343 	}
344 
345 	list_del(&nt->entry);
346 }
347 
348 static void ntb_transport_client_release(struct device *dev)
349 {
350 	struct ntb_transport_client_dev *client_dev;
351 
352 	client_dev = dev_client_dev(dev);
353 	kfree(client_dev);
354 }
355 
356 /**
357  * ntb_transport_unregister_client_dev - Unregister NTB client device
358  * @device_name: Name of NTB client device
359  *
360  * Unregister an NTB client device with the NTB transport layer
361  */
362 void ntb_transport_unregister_client_dev(char *device_name)
363 {
364 	struct ntb_transport_client_dev *client, *cd;
365 	struct ntb_transport_ctx *nt;
366 
367 	list_for_each_entry(nt, &ntb_transport_list, entry)
368 		list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
369 			if (!strncmp(dev_name(&client->dev), device_name,
370 				     strlen(device_name))) {
371 				list_del(&client->entry);
372 				device_unregister(&client->dev);
373 			}
374 }
375 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
376 
377 /**
378  * ntb_transport_register_client_dev - Register NTB client device
379  * @device_name: Name of NTB client device
380  *
381  * Register an NTB client device with the NTB transport layer
382  */
383 int ntb_transport_register_client_dev(char *device_name)
384 {
385 	struct ntb_transport_client_dev *client_dev;
386 	struct ntb_transport_ctx *nt;
387 	int node;
388 	int rc, i = 0;
389 
390 	if (list_empty(&ntb_transport_list))
391 		return -ENODEV;
392 
393 	list_for_each_entry(nt, &ntb_transport_list, entry) {
394 		struct device *dev;
395 
396 		node = dev_to_node(&nt->ndev->dev);
397 
398 		client_dev = kzalloc_node(sizeof(*client_dev),
399 					  GFP_KERNEL, node);
400 		if (!client_dev) {
401 			rc = -ENOMEM;
402 			goto err;
403 		}
404 
405 		dev = &client_dev->dev;
406 
407 		/* setup and register client devices */
408 		dev_set_name(dev, "%s%d", device_name, i);
409 		dev->bus = &ntb_transport_bus;
410 		dev->release = ntb_transport_client_release;
411 		dev->parent = &nt->ndev->dev;
412 
413 		rc = device_register(dev);
414 		if (rc) {
415 			kfree(client_dev);
416 			goto err;
417 		}
418 
419 		list_add_tail(&client_dev->entry, &nt->client_devs);
420 		i++;
421 	}
422 
423 	return 0;
424 
425 err:
426 	ntb_transport_unregister_client_dev(device_name);
427 
428 	return rc;
429 }
430 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
431 
432 /**
433  * ntb_transport_register_client - Register NTB client driver
434  * @drv: NTB client driver to be registered
435  *
436  * Register an NTB client driver with the NTB transport layer
437  *
438  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
439  */
440 int ntb_transport_register_client(struct ntb_transport_client *drv)
441 {
442 	drv->driver.bus = &ntb_transport_bus;
443 
444 	if (list_empty(&ntb_transport_list))
445 		return -ENODEV;
446 
447 	return driver_register(&drv->driver);
448 }
449 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
450 
451 /**
452  * ntb_transport_unregister_client - Unregister NTB client driver
453  * @drv: NTB client driver to be unregistered
454  *
455  * Unregister an NTB client driver with the NTB transport layer
456  *
457  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
458  */
459 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
460 {
461 	driver_unregister(&drv->driver);
462 }
463 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
464 
465 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
466 			    loff_t *offp)
467 {
468 	struct ntb_transport_qp *qp;
469 	char *buf;
470 	ssize_t ret, out_offset, out_count;
471 
472 	qp = filp->private_data;
473 
474 	if (!qp || !qp->link_is_up)
475 		return 0;
476 
477 	out_count = 1000;
478 
479 	buf = kmalloc(out_count, GFP_KERNEL);
480 	if (!buf)
481 		return -ENOMEM;
482 
483 	out_offset = 0;
484 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
485 			       "\nNTB QP stats:\n\n");
486 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
487 			       "rx_bytes - \t%llu\n", qp->rx_bytes);
488 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
489 			       "rx_pkts - \t%llu\n", qp->rx_pkts);
490 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
491 			       "rx_memcpy - \t%llu\n", qp->rx_memcpy);
492 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
493 			       "rx_async - \t%llu\n", qp->rx_async);
494 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
495 			       "rx_ring_empty - %llu\n", qp->rx_ring_empty);
496 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
497 			       "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
498 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
499 			       "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
500 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
501 			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
502 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
503 			       "rx_buff - \t0x%p\n", qp->rx_buff);
504 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
505 			       "rx_index - \t%u\n", qp->rx_index);
506 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
507 			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
508 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
509 			       "rx_alloc_entry - \t%u\n\n", qp->rx_alloc_entry);
510 
511 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
512 			       "tx_bytes - \t%llu\n", qp->tx_bytes);
513 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
514 			       "tx_pkts - \t%llu\n", qp->tx_pkts);
515 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
516 			       "tx_memcpy - \t%llu\n", qp->tx_memcpy);
517 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
518 			       "tx_async - \t%llu\n", qp->tx_async);
519 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
520 			       "tx_ring_full - \t%llu\n", qp->tx_ring_full);
521 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
522 			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
523 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
524 			       "tx_mw - \t0x%p\n", qp->tx_mw);
525 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
526 			       "tx_index (H) - \t%u\n", qp->tx_index);
527 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
528 			       "RRI (T) - \t%u\n",
529 			       qp->remote_rx_info->entry);
530 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
531 			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
532 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
533 			       "free tx - \t%u\n",
534 			       ntb_transport_tx_free_entry(qp));
535 
536 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
537 			       "\n");
538 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
539 			       "Using TX DMA - \t%s\n",
540 			       qp->tx_dma_chan ? "Yes" : "No");
541 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
542 			       "Using RX DMA - \t%s\n",
543 			       qp->rx_dma_chan ? "Yes" : "No");
544 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
545 			       "QP Link - \t%s\n",
546 			       qp->link_is_up ? "Up" : "Down");
547 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
548 			       "\n");
549 
550 	if (out_offset > out_count)
551 		out_offset = out_count;
552 
553 	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
554 	kfree(buf);
555 	return ret;
556 }
557 
558 static const struct file_operations ntb_qp_debugfs_stats = {
559 	.owner = THIS_MODULE,
560 	.open = simple_open,
561 	.read = debugfs_read,
562 };
563 
564 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
565 			 struct list_head *list)
566 {
567 	unsigned long flags;
568 
569 	spin_lock_irqsave(lock, flags);
570 	list_add_tail(entry, list);
571 	spin_unlock_irqrestore(lock, flags);
572 }
573 
574 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
575 					   struct list_head *list)
576 {
577 	struct ntb_queue_entry *entry;
578 	unsigned long flags;
579 
580 	spin_lock_irqsave(lock, flags);
581 	if (list_empty(list)) {
582 		entry = NULL;
583 		goto out;
584 	}
585 	entry = list_first_entry(list, struct ntb_queue_entry, entry);
586 	list_del(&entry->entry);
587 
588 out:
589 	spin_unlock_irqrestore(lock, flags);
590 
591 	return entry;
592 }
593 
594 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
595 					   struct list_head *list,
596 					   struct list_head *to_list)
597 {
598 	struct ntb_queue_entry *entry;
599 	unsigned long flags;
600 
601 	spin_lock_irqsave(lock, flags);
602 
603 	if (list_empty(list)) {
604 		entry = NULL;
605 	} else {
606 		entry = list_first_entry(list, struct ntb_queue_entry, entry);
607 		list_move_tail(&entry->entry, to_list);
608 	}
609 
610 	spin_unlock_irqrestore(lock, flags);
611 
612 	return entry;
613 }
614 
615 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
616 				     unsigned int qp_num)
617 {
618 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
619 	struct ntb_transport_mw *mw;
620 	struct ntb_dev *ndev = nt->ndev;
621 	struct ntb_queue_entry *entry;
622 	unsigned int rx_size, num_qps_mw;
623 	unsigned int mw_num, mw_count, qp_count;
624 	unsigned int i;
625 	int node;
626 
627 	mw_count = nt->mw_count;
628 	qp_count = nt->qp_count;
629 
630 	mw_num = QP_TO_MW(nt, qp_num);
631 	mw = &nt->mw_vec[mw_num];
632 
633 	if (!mw->virt_addr)
634 		return -ENOMEM;
635 
636 	if (mw_num < qp_count % mw_count)
637 		num_qps_mw = qp_count / mw_count + 1;
638 	else
639 		num_qps_mw = qp_count / mw_count;
640 
641 	rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
642 	qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
643 	rx_size -= sizeof(struct ntb_rx_info);
644 
645 	qp->remote_rx_info = qp->rx_buff + rx_size;
646 
647 	/* Due to housekeeping, there must be atleast 2 buffs */
648 	qp->rx_max_frame = min(transport_mtu, rx_size / 2);
649 	qp->rx_max_entry = rx_size / qp->rx_max_frame;
650 	qp->rx_index = 0;
651 
652 	/*
653 	 * Checking to see if we have more entries than the default.
654 	 * We should add additional entries if that is the case so we
655 	 * can be in sync with the transport frames.
656 	 */
657 	node = dev_to_node(&ndev->dev);
658 	for (i = qp->rx_alloc_entry; i < qp->rx_max_entry; i++) {
659 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
660 		if (!entry)
661 			return -ENOMEM;
662 
663 		entry->qp = qp;
664 		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
665 			     &qp->rx_free_q);
666 		qp->rx_alloc_entry++;
667 	}
668 
669 	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
670 
671 	/* setup the hdr offsets with 0's */
672 	for (i = 0; i < qp->rx_max_entry; i++) {
673 		void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
674 				sizeof(struct ntb_payload_header));
675 		memset(offset, 0, sizeof(struct ntb_payload_header));
676 	}
677 
678 	qp->rx_pkts = 0;
679 	qp->tx_pkts = 0;
680 	qp->tx_index = 0;
681 
682 	return 0;
683 }
684 
685 static irqreturn_t ntb_transport_isr(int irq, void *dev)
686 {
687 	struct ntb_transport_qp *qp = dev;
688 
689 	tasklet_schedule(&qp->rxc_db_work);
690 
691 	return IRQ_HANDLED;
692 }
693 
694 static void ntb_transport_setup_qp_peer_msi(struct ntb_transport_ctx *nt,
695 					    unsigned int qp_num)
696 {
697 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
698 	int spad = qp_num * 2 + nt->msi_spad_offset;
699 
700 	if (!nt->use_msi)
701 		return;
702 
703 	if (spad >= ntb_spad_count(nt->ndev))
704 		return;
705 
706 	qp->peer_msi_desc.addr_offset =
707 		ntb_peer_spad_read(qp->ndev, PIDX, spad);
708 	qp->peer_msi_desc.data =
709 		ntb_peer_spad_read(qp->ndev, PIDX, spad + 1);
710 
711 	dev_dbg(&qp->ndev->pdev->dev, "QP%d Peer MSI addr=%x data=%x\n",
712 		qp_num, qp->peer_msi_desc.addr_offset, qp->peer_msi_desc.data);
713 
714 	if (qp->peer_msi_desc.addr_offset) {
715 		qp->use_msi = true;
716 		dev_info(&qp->ndev->pdev->dev,
717 			 "Using MSI interrupts for QP%d\n", qp_num);
718 	}
719 }
720 
721 static void ntb_transport_setup_qp_msi(struct ntb_transport_ctx *nt,
722 				       unsigned int qp_num)
723 {
724 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
725 	int spad = qp_num * 2 + nt->msi_spad_offset;
726 	int rc;
727 
728 	if (!nt->use_msi)
729 		return;
730 
731 	if (spad >= ntb_spad_count(nt->ndev)) {
732 		dev_warn_once(&qp->ndev->pdev->dev,
733 			      "Not enough SPADS to use MSI interrupts\n");
734 		return;
735 	}
736 
737 	ntb_spad_write(qp->ndev, spad, 0);
738 	ntb_spad_write(qp->ndev, spad + 1, 0);
739 
740 	if (!qp->msi_irq) {
741 		qp->msi_irq = ntbm_msi_request_irq(qp->ndev, ntb_transport_isr,
742 						   KBUILD_MODNAME, qp,
743 						   &qp->msi_desc);
744 		if (qp->msi_irq < 0) {
745 			dev_warn(&qp->ndev->pdev->dev,
746 				 "Unable to allocate MSI interrupt for qp%d\n",
747 				 qp_num);
748 			return;
749 		}
750 	}
751 
752 	rc = ntb_spad_write(qp->ndev, spad, qp->msi_desc.addr_offset);
753 	if (rc)
754 		goto err_free_interrupt;
755 
756 	rc = ntb_spad_write(qp->ndev, spad + 1, qp->msi_desc.data);
757 	if (rc)
758 		goto err_free_interrupt;
759 
760 	dev_dbg(&qp->ndev->pdev->dev, "QP%d MSI %d addr=%x data=%x\n",
761 		qp_num, qp->msi_irq, qp->msi_desc.addr_offset,
762 		qp->msi_desc.data);
763 
764 	return;
765 
766 err_free_interrupt:
767 	devm_free_irq(&nt->ndev->dev, qp->msi_irq, qp);
768 }
769 
770 static void ntb_transport_msi_peer_desc_changed(struct ntb_transport_ctx *nt)
771 {
772 	int i;
773 
774 	dev_dbg(&nt->ndev->pdev->dev, "Peer MSI descriptors changed");
775 
776 	for (i = 0; i < nt->qp_count; i++)
777 		ntb_transport_setup_qp_peer_msi(nt, i);
778 }
779 
780 static void ntb_transport_msi_desc_changed(void *data)
781 {
782 	struct ntb_transport_ctx *nt = data;
783 	int i;
784 
785 	dev_dbg(&nt->ndev->pdev->dev, "MSI descriptors changed");
786 
787 	for (i = 0; i < nt->qp_count; i++)
788 		ntb_transport_setup_qp_msi(nt, i);
789 
790 	ntb_peer_db_set(nt->ndev, nt->msi_db_mask);
791 }
792 
793 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
794 {
795 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
796 	struct pci_dev *pdev = nt->ndev->pdev;
797 
798 	if (!mw->virt_addr)
799 		return;
800 
801 	ntb_mw_clear_trans(nt->ndev, PIDX, num_mw);
802 	dma_free_coherent(&pdev->dev, mw->alloc_size,
803 			  mw->alloc_addr, mw->dma_addr);
804 	mw->xlat_size = 0;
805 	mw->buff_size = 0;
806 	mw->alloc_size = 0;
807 	mw->alloc_addr = NULL;
808 	mw->virt_addr = NULL;
809 }
810 
811 static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
812 			       struct device *dma_dev, size_t align)
813 {
814 	dma_addr_t dma_addr;
815 	void *alloc_addr, *virt_addr;
816 	int rc;
817 
818 	alloc_addr = dma_alloc_coherent(dma_dev, mw->alloc_size,
819 					&dma_addr, GFP_KERNEL);
820 	if (!alloc_addr) {
821 		dev_err(dma_dev, "Unable to alloc MW buff of size %zu\n",
822 			mw->alloc_size);
823 		return -ENOMEM;
824 	}
825 	virt_addr = alloc_addr;
826 
827 	/*
828 	 * we must ensure that the memory address allocated is BAR size
829 	 * aligned in order for the XLAT register to take the value. This
830 	 * is a requirement of the hardware. It is recommended to setup CMA
831 	 * for BAR sizes equal or greater than 4MB.
832 	 */
833 	if (!IS_ALIGNED(dma_addr, align)) {
834 		if (mw->alloc_size > mw->buff_size) {
835 			virt_addr = PTR_ALIGN(alloc_addr, align);
836 			dma_addr = ALIGN(dma_addr, align);
837 		} else {
838 			rc = -ENOMEM;
839 			goto err;
840 		}
841 	}
842 
843 	mw->alloc_addr = alloc_addr;
844 	mw->virt_addr = virt_addr;
845 	mw->dma_addr = dma_addr;
846 
847 	return 0;
848 
849 err:
850 	dma_free_coherent(dma_dev, mw->alloc_size, alloc_addr, dma_addr);
851 
852 	return rc;
853 }
854 
855 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
856 		      resource_size_t size)
857 {
858 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
859 	struct pci_dev *pdev = nt->ndev->pdev;
860 	size_t xlat_size, buff_size;
861 	resource_size_t xlat_align;
862 	resource_size_t xlat_align_size;
863 	int rc;
864 
865 	if (!size)
866 		return -EINVAL;
867 
868 	rc = ntb_mw_get_align(nt->ndev, PIDX, num_mw, &xlat_align,
869 			      &xlat_align_size, NULL);
870 	if (rc)
871 		return rc;
872 
873 	xlat_size = round_up(size, xlat_align_size);
874 	buff_size = round_up(size, xlat_align);
875 
876 	/* No need to re-setup */
877 	if (mw->xlat_size == xlat_size)
878 		return 0;
879 
880 	if (mw->buff_size)
881 		ntb_free_mw(nt, num_mw);
882 
883 	/* Alloc memory for receiving data.  Must be aligned */
884 	mw->xlat_size = xlat_size;
885 	mw->buff_size = buff_size;
886 	mw->alloc_size = buff_size;
887 
888 	rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
889 	if (rc) {
890 		mw->alloc_size *= 2;
891 		rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
892 		if (rc) {
893 			dev_err(&pdev->dev,
894 				"Unable to alloc aligned MW buff\n");
895 			mw->xlat_size = 0;
896 			mw->buff_size = 0;
897 			mw->alloc_size = 0;
898 			return rc;
899 		}
900 	}
901 
902 	/* Notify HW the memory location of the receive buffer */
903 	rc = ntb_mw_set_trans(nt->ndev, PIDX, num_mw, mw->dma_addr,
904 			      mw->xlat_size);
905 	if (rc) {
906 		dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
907 		ntb_free_mw(nt, num_mw);
908 		return -EIO;
909 	}
910 
911 	return 0;
912 }
913 
914 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
915 {
916 	qp->link_is_up = false;
917 	qp->active = false;
918 
919 	qp->tx_index = 0;
920 	qp->rx_index = 0;
921 	qp->rx_bytes = 0;
922 	qp->rx_pkts = 0;
923 	qp->rx_ring_empty = 0;
924 	qp->rx_err_no_buf = 0;
925 	qp->rx_err_oflow = 0;
926 	qp->rx_err_ver = 0;
927 	qp->rx_memcpy = 0;
928 	qp->rx_async = 0;
929 	qp->tx_bytes = 0;
930 	qp->tx_pkts = 0;
931 	qp->tx_ring_full = 0;
932 	qp->tx_err_no_buf = 0;
933 	qp->tx_memcpy = 0;
934 	qp->tx_async = 0;
935 }
936 
937 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
938 {
939 	struct ntb_transport_ctx *nt = qp->transport;
940 	struct pci_dev *pdev = nt->ndev->pdev;
941 
942 	dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
943 
944 	cancel_delayed_work_sync(&qp->link_work);
945 	ntb_qp_link_down_reset(qp);
946 
947 	if (qp->event_handler)
948 		qp->event_handler(qp->cb_data, qp->link_is_up);
949 }
950 
951 static void ntb_qp_link_cleanup_work(struct work_struct *work)
952 {
953 	struct ntb_transport_qp *qp = container_of(work,
954 						   struct ntb_transport_qp,
955 						   link_cleanup);
956 	struct ntb_transport_ctx *nt = qp->transport;
957 
958 	ntb_qp_link_cleanup(qp);
959 
960 	if (nt->link_is_up)
961 		schedule_delayed_work(&qp->link_work,
962 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
963 }
964 
965 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
966 {
967 	schedule_work(&qp->link_cleanup);
968 }
969 
970 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
971 {
972 	struct ntb_transport_qp *qp;
973 	u64 qp_bitmap_alloc;
974 	unsigned int i, count;
975 
976 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
977 
978 	/* Pass along the info to any clients */
979 	for (i = 0; i < nt->qp_count; i++)
980 		if (qp_bitmap_alloc & BIT_ULL(i)) {
981 			qp = &nt->qp_vec[i];
982 			ntb_qp_link_cleanup(qp);
983 			cancel_work_sync(&qp->link_cleanup);
984 			cancel_delayed_work_sync(&qp->link_work);
985 		}
986 
987 	if (!nt->link_is_up)
988 		cancel_delayed_work_sync(&nt->link_work);
989 
990 	for (i = 0; i < nt->mw_count; i++)
991 		ntb_free_mw(nt, i);
992 
993 	/* The scratchpad registers keep the values if the remote side
994 	 * goes down, blast them now to give them a sane value the next
995 	 * time they are accessed
996 	 */
997 	count = ntb_spad_count(nt->ndev);
998 	for (i = 0; i < count; i++)
999 		ntb_spad_write(nt->ndev, i, 0);
1000 }
1001 
1002 static void ntb_transport_link_cleanup_work(struct work_struct *work)
1003 {
1004 	struct ntb_transport_ctx *nt =
1005 		container_of(work, struct ntb_transport_ctx, link_cleanup);
1006 
1007 	ntb_transport_link_cleanup(nt);
1008 }
1009 
1010 static void ntb_transport_event_callback(void *data)
1011 {
1012 	struct ntb_transport_ctx *nt = data;
1013 
1014 	if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
1015 		schedule_delayed_work(&nt->link_work, 0);
1016 	else
1017 		schedule_work(&nt->link_cleanup);
1018 }
1019 
1020 static void ntb_transport_link_work(struct work_struct *work)
1021 {
1022 	struct ntb_transport_ctx *nt =
1023 		container_of(work, struct ntb_transport_ctx, link_work.work);
1024 	struct ntb_dev *ndev = nt->ndev;
1025 	struct pci_dev *pdev = ndev->pdev;
1026 	resource_size_t size;
1027 	u32 val;
1028 	int rc = 0, i, spad;
1029 
1030 	/* send the local info, in the opposite order of the way we read it */
1031 
1032 	if (nt->use_msi) {
1033 		rc = ntb_msi_setup_mws(ndev);
1034 		if (rc) {
1035 			dev_warn(&pdev->dev,
1036 				 "Failed to register MSI memory window: %d\n",
1037 				 rc);
1038 			nt->use_msi = false;
1039 		}
1040 	}
1041 
1042 	for (i = 0; i < nt->qp_count; i++)
1043 		ntb_transport_setup_qp_msi(nt, i);
1044 
1045 	for (i = 0; i < nt->mw_count; i++) {
1046 		size = nt->mw_vec[i].phys_size;
1047 
1048 		if (max_mw_size && size > max_mw_size)
1049 			size = max_mw_size;
1050 
1051 		spad = MW0_SZ_HIGH + (i * 2);
1052 		ntb_peer_spad_write(ndev, PIDX, spad, upper_32_bits(size));
1053 
1054 		spad = MW0_SZ_LOW + (i * 2);
1055 		ntb_peer_spad_write(ndev, PIDX, spad, lower_32_bits(size));
1056 	}
1057 
1058 	ntb_peer_spad_write(ndev, PIDX, NUM_MWS, nt->mw_count);
1059 
1060 	ntb_peer_spad_write(ndev, PIDX, NUM_QPS, nt->qp_count);
1061 
1062 	ntb_peer_spad_write(ndev, PIDX, VERSION, NTB_TRANSPORT_VERSION);
1063 
1064 	/* Query the remote side for its info */
1065 	val = ntb_spad_read(ndev, VERSION);
1066 	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
1067 	if (val != NTB_TRANSPORT_VERSION)
1068 		goto out;
1069 
1070 	val = ntb_spad_read(ndev, NUM_QPS);
1071 	dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
1072 	if (val != nt->qp_count)
1073 		goto out;
1074 
1075 	val = ntb_spad_read(ndev, NUM_MWS);
1076 	dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
1077 	if (val != nt->mw_count)
1078 		goto out;
1079 
1080 	for (i = 0; i < nt->mw_count; i++) {
1081 		u64 val64;
1082 
1083 		val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
1084 		val64 = (u64)val << 32;
1085 
1086 		val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
1087 		val64 |= val;
1088 
1089 		dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
1090 
1091 		rc = ntb_set_mw(nt, i, val64);
1092 		if (rc)
1093 			goto out1;
1094 	}
1095 
1096 	nt->link_is_up = true;
1097 
1098 	for (i = 0; i < nt->qp_count; i++) {
1099 		struct ntb_transport_qp *qp = &nt->qp_vec[i];
1100 
1101 		ntb_transport_setup_qp_mw(nt, i);
1102 		ntb_transport_setup_qp_peer_msi(nt, i);
1103 
1104 		if (qp->client_ready)
1105 			schedule_delayed_work(&qp->link_work, 0);
1106 	}
1107 
1108 	return;
1109 
1110 out1:
1111 	for (i = 0; i < nt->mw_count; i++)
1112 		ntb_free_mw(nt, i);
1113 
1114 	/* if there's an actual failure, we should just bail */
1115 	if (rc < 0)
1116 		return;
1117 
1118 out:
1119 	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
1120 		schedule_delayed_work(&nt->link_work,
1121 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
1122 }
1123 
1124 static void ntb_qp_link_work(struct work_struct *work)
1125 {
1126 	struct ntb_transport_qp *qp = container_of(work,
1127 						   struct ntb_transport_qp,
1128 						   link_work.work);
1129 	struct pci_dev *pdev = qp->ndev->pdev;
1130 	struct ntb_transport_ctx *nt = qp->transport;
1131 	int val;
1132 
1133 	WARN_ON(!nt->link_is_up);
1134 
1135 	val = ntb_spad_read(nt->ndev, QP_LINKS);
1136 
1137 	ntb_peer_spad_write(nt->ndev, PIDX, QP_LINKS, val | BIT(qp->qp_num));
1138 
1139 	/* query remote spad for qp ready bits */
1140 	dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
1141 
1142 	/* See if the remote side is up */
1143 	if (val & BIT(qp->qp_num)) {
1144 		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
1145 		qp->link_is_up = true;
1146 		qp->active = true;
1147 
1148 		if (qp->event_handler)
1149 			qp->event_handler(qp->cb_data, qp->link_is_up);
1150 
1151 		if (qp->active)
1152 			tasklet_schedule(&qp->rxc_db_work);
1153 	} else if (nt->link_is_up)
1154 		schedule_delayed_work(&qp->link_work,
1155 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
1156 }
1157 
1158 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
1159 				    unsigned int qp_num)
1160 {
1161 	struct ntb_transport_qp *qp;
1162 	phys_addr_t mw_base;
1163 	resource_size_t mw_size;
1164 	unsigned int num_qps_mw, tx_size;
1165 	unsigned int mw_num, mw_count, qp_count;
1166 	u64 qp_offset;
1167 
1168 	mw_count = nt->mw_count;
1169 	qp_count = nt->qp_count;
1170 
1171 	mw_num = QP_TO_MW(nt, qp_num);
1172 
1173 	qp = &nt->qp_vec[qp_num];
1174 	qp->qp_num = qp_num;
1175 	qp->transport = nt;
1176 	qp->ndev = nt->ndev;
1177 	qp->client_ready = false;
1178 	qp->event_handler = NULL;
1179 	ntb_qp_link_down_reset(qp);
1180 
1181 	if (mw_num < qp_count % mw_count)
1182 		num_qps_mw = qp_count / mw_count + 1;
1183 	else
1184 		num_qps_mw = qp_count / mw_count;
1185 
1186 	mw_base = nt->mw_vec[mw_num].phys_addr;
1187 	mw_size = nt->mw_vec[mw_num].phys_size;
1188 
1189 	if (max_mw_size && mw_size > max_mw_size)
1190 		mw_size = max_mw_size;
1191 
1192 	tx_size = (unsigned int)mw_size / num_qps_mw;
1193 	qp_offset = tx_size * (qp_num / mw_count);
1194 
1195 	qp->tx_mw_size = tx_size;
1196 	qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
1197 	if (!qp->tx_mw)
1198 		return -EINVAL;
1199 
1200 	qp->tx_mw_phys = mw_base + qp_offset;
1201 	if (!qp->tx_mw_phys)
1202 		return -EINVAL;
1203 
1204 	tx_size -= sizeof(struct ntb_rx_info);
1205 	qp->rx_info = qp->tx_mw + tx_size;
1206 
1207 	/* Due to housekeeping, there must be atleast 2 buffs */
1208 	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
1209 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
1210 
1211 	if (nt->debugfs_node_dir) {
1212 		char debugfs_name[4];
1213 
1214 		snprintf(debugfs_name, 4, "qp%d", qp_num);
1215 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
1216 						     nt->debugfs_node_dir);
1217 
1218 		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
1219 							qp->debugfs_dir, qp,
1220 							&ntb_qp_debugfs_stats);
1221 	} else {
1222 		qp->debugfs_dir = NULL;
1223 		qp->debugfs_stats = NULL;
1224 	}
1225 
1226 	INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
1227 	INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
1228 
1229 	spin_lock_init(&qp->ntb_rx_q_lock);
1230 	spin_lock_init(&qp->ntb_tx_free_q_lock);
1231 
1232 	INIT_LIST_HEAD(&qp->rx_post_q);
1233 	INIT_LIST_HEAD(&qp->rx_pend_q);
1234 	INIT_LIST_HEAD(&qp->rx_free_q);
1235 	INIT_LIST_HEAD(&qp->tx_free_q);
1236 
1237 	tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
1238 		     (unsigned long)qp);
1239 
1240 	return 0;
1241 }
1242 
1243 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
1244 {
1245 	struct ntb_transport_ctx *nt;
1246 	struct ntb_transport_mw *mw;
1247 	unsigned int mw_count, qp_count, spad_count, max_mw_count_for_spads;
1248 	u64 qp_bitmap;
1249 	int node;
1250 	int rc, i;
1251 
1252 	mw_count = ntb_peer_mw_count(ndev);
1253 
1254 	if (!ndev->ops->mw_set_trans) {
1255 		dev_err(&ndev->dev, "Inbound MW based NTB API is required\n");
1256 		return -EINVAL;
1257 	}
1258 
1259 	if (ntb_db_is_unsafe(ndev))
1260 		dev_dbg(&ndev->dev,
1261 			"doorbell is unsafe, proceed anyway...\n");
1262 	if (ntb_spad_is_unsafe(ndev))
1263 		dev_dbg(&ndev->dev,
1264 			"scratchpad is unsafe, proceed anyway...\n");
1265 
1266 	if (ntb_peer_port_count(ndev) != NTB_DEF_PEER_CNT)
1267 		dev_warn(&ndev->dev, "Multi-port NTB devices unsupported\n");
1268 
1269 	node = dev_to_node(&ndev->dev);
1270 
1271 	nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1272 	if (!nt)
1273 		return -ENOMEM;
1274 
1275 	nt->ndev = ndev;
1276 
1277 	/*
1278 	 * If we are using MSI, and have at least one extra memory window,
1279 	 * we will reserve the last MW for the MSI window.
1280 	 */
1281 	if (use_msi && mw_count > 1) {
1282 		rc = ntb_msi_init(ndev, ntb_transport_msi_desc_changed);
1283 		if (!rc) {
1284 			mw_count -= 1;
1285 			nt->use_msi = true;
1286 		}
1287 	}
1288 
1289 	spad_count = ntb_spad_count(ndev);
1290 
1291 	/* Limit the MW's based on the availability of scratchpads */
1292 
1293 	if (spad_count < NTB_TRANSPORT_MIN_SPADS) {
1294 		nt->mw_count = 0;
1295 		rc = -EINVAL;
1296 		goto err;
1297 	}
1298 
1299 	max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
1300 	nt->mw_count = min(mw_count, max_mw_count_for_spads);
1301 
1302 	nt->msi_spad_offset = nt->mw_count * 2 + MW0_SZ_HIGH;
1303 
1304 	nt->mw_vec = kcalloc_node(mw_count, sizeof(*nt->mw_vec),
1305 				  GFP_KERNEL, node);
1306 	if (!nt->mw_vec) {
1307 		rc = -ENOMEM;
1308 		goto err;
1309 	}
1310 
1311 	for (i = 0; i < mw_count; i++) {
1312 		mw = &nt->mw_vec[i];
1313 
1314 		rc = ntb_peer_mw_get_addr(ndev, i, &mw->phys_addr,
1315 					  &mw->phys_size);
1316 		if (rc)
1317 			goto err1;
1318 
1319 		mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1320 		if (!mw->vbase) {
1321 			rc = -ENOMEM;
1322 			goto err1;
1323 		}
1324 
1325 		mw->buff_size = 0;
1326 		mw->xlat_size = 0;
1327 		mw->virt_addr = NULL;
1328 		mw->dma_addr = 0;
1329 	}
1330 
1331 	qp_bitmap = ntb_db_valid_mask(ndev);
1332 
1333 	qp_count = ilog2(qp_bitmap);
1334 	if (nt->use_msi) {
1335 		qp_count -= 1;
1336 		nt->msi_db_mask = 1 << qp_count;
1337 		ntb_db_clear_mask(ndev, nt->msi_db_mask);
1338 	}
1339 
1340 	if (max_num_clients && max_num_clients < qp_count)
1341 		qp_count = max_num_clients;
1342 	else if (nt->mw_count < qp_count)
1343 		qp_count = nt->mw_count;
1344 
1345 	qp_bitmap &= BIT_ULL(qp_count) - 1;
1346 
1347 	nt->qp_count = qp_count;
1348 	nt->qp_bitmap = qp_bitmap;
1349 	nt->qp_bitmap_free = qp_bitmap;
1350 
1351 	nt->qp_vec = kcalloc_node(qp_count, sizeof(*nt->qp_vec),
1352 				  GFP_KERNEL, node);
1353 	if (!nt->qp_vec) {
1354 		rc = -ENOMEM;
1355 		goto err1;
1356 	}
1357 
1358 	if (nt_debugfs_dir) {
1359 		nt->debugfs_node_dir =
1360 			debugfs_create_dir(pci_name(ndev->pdev),
1361 					   nt_debugfs_dir);
1362 	}
1363 
1364 	for (i = 0; i < qp_count; i++) {
1365 		rc = ntb_transport_init_queue(nt, i);
1366 		if (rc)
1367 			goto err2;
1368 	}
1369 
1370 	INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1371 	INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1372 
1373 	rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1374 	if (rc)
1375 		goto err2;
1376 
1377 	INIT_LIST_HEAD(&nt->client_devs);
1378 	rc = ntb_bus_init(nt);
1379 	if (rc)
1380 		goto err3;
1381 
1382 	nt->link_is_up = false;
1383 	ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1384 	ntb_link_event(ndev);
1385 
1386 	return 0;
1387 
1388 err3:
1389 	ntb_clear_ctx(ndev);
1390 err2:
1391 	kfree(nt->qp_vec);
1392 err1:
1393 	while (i--) {
1394 		mw = &nt->mw_vec[i];
1395 		iounmap(mw->vbase);
1396 	}
1397 	kfree(nt->mw_vec);
1398 err:
1399 	kfree(nt);
1400 	return rc;
1401 }
1402 
1403 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1404 {
1405 	struct ntb_transport_ctx *nt = ndev->ctx;
1406 	struct ntb_transport_qp *qp;
1407 	u64 qp_bitmap_alloc;
1408 	int i;
1409 
1410 	ntb_transport_link_cleanup(nt);
1411 	cancel_work_sync(&nt->link_cleanup);
1412 	cancel_delayed_work_sync(&nt->link_work);
1413 
1414 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1415 
1416 	/* verify that all the qp's are freed */
1417 	for (i = 0; i < nt->qp_count; i++) {
1418 		qp = &nt->qp_vec[i];
1419 		if (qp_bitmap_alloc & BIT_ULL(i))
1420 			ntb_transport_free_queue(qp);
1421 		debugfs_remove_recursive(qp->debugfs_dir);
1422 	}
1423 
1424 	ntb_link_disable(ndev);
1425 	ntb_clear_ctx(ndev);
1426 
1427 	ntb_bus_remove(nt);
1428 
1429 	for (i = nt->mw_count; i--; ) {
1430 		ntb_free_mw(nt, i);
1431 		iounmap(nt->mw_vec[i].vbase);
1432 	}
1433 
1434 	kfree(nt->qp_vec);
1435 	kfree(nt->mw_vec);
1436 	kfree(nt);
1437 }
1438 
1439 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1440 {
1441 	struct ntb_queue_entry *entry;
1442 	void *cb_data;
1443 	unsigned int len;
1444 	unsigned long irqflags;
1445 
1446 	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1447 
1448 	while (!list_empty(&qp->rx_post_q)) {
1449 		entry = list_first_entry(&qp->rx_post_q,
1450 					 struct ntb_queue_entry, entry);
1451 		if (!(entry->flags & DESC_DONE_FLAG))
1452 			break;
1453 
1454 		entry->rx_hdr->flags = 0;
1455 		iowrite32(entry->rx_index, &qp->rx_info->entry);
1456 
1457 		cb_data = entry->cb_data;
1458 		len = entry->len;
1459 
1460 		list_move_tail(&entry->entry, &qp->rx_free_q);
1461 
1462 		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1463 
1464 		if (qp->rx_handler && qp->client_ready)
1465 			qp->rx_handler(qp, qp->cb_data, cb_data, len);
1466 
1467 		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1468 	}
1469 
1470 	spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1471 }
1472 
1473 static void ntb_rx_copy_callback(void *data,
1474 				 const struct dmaengine_result *res)
1475 {
1476 	struct ntb_queue_entry *entry = data;
1477 
1478 	/* we need to check DMA results if we are using DMA */
1479 	if (res) {
1480 		enum dmaengine_tx_result dma_err = res->result;
1481 
1482 		switch (dma_err) {
1483 		case DMA_TRANS_READ_FAILED:
1484 		case DMA_TRANS_WRITE_FAILED:
1485 			entry->errors++;
1486 			fallthrough;
1487 		case DMA_TRANS_ABORTED:
1488 		{
1489 			struct ntb_transport_qp *qp = entry->qp;
1490 			void *offset = qp->rx_buff + qp->rx_max_frame *
1491 					qp->rx_index;
1492 
1493 			ntb_memcpy_rx(entry, offset);
1494 			qp->rx_memcpy++;
1495 			return;
1496 		}
1497 
1498 		case DMA_TRANS_NOERROR:
1499 		default:
1500 			break;
1501 		}
1502 	}
1503 
1504 	entry->flags |= DESC_DONE_FLAG;
1505 
1506 	ntb_complete_rxc(entry->qp);
1507 }
1508 
1509 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1510 {
1511 	void *buf = entry->buf;
1512 	size_t len = entry->len;
1513 
1514 	memcpy(buf, offset, len);
1515 
1516 	/* Ensure that the data is fully copied out before clearing the flag */
1517 	wmb();
1518 
1519 	ntb_rx_copy_callback(entry, NULL);
1520 }
1521 
1522 static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset)
1523 {
1524 	struct dma_async_tx_descriptor *txd;
1525 	struct ntb_transport_qp *qp = entry->qp;
1526 	struct dma_chan *chan = qp->rx_dma_chan;
1527 	struct dma_device *device;
1528 	size_t pay_off, buff_off, len;
1529 	struct dmaengine_unmap_data *unmap;
1530 	dma_cookie_t cookie;
1531 	void *buf = entry->buf;
1532 
1533 	len = entry->len;
1534 	device = chan->device;
1535 	pay_off = (size_t)offset & ~PAGE_MASK;
1536 	buff_off = (size_t)buf & ~PAGE_MASK;
1537 
1538 	if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1539 		goto err;
1540 
1541 	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1542 	if (!unmap)
1543 		goto err;
1544 
1545 	unmap->len = len;
1546 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1547 				      pay_off, len, DMA_TO_DEVICE);
1548 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1549 		goto err_get_unmap;
1550 
1551 	unmap->to_cnt = 1;
1552 
1553 	unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1554 				      buff_off, len, DMA_FROM_DEVICE);
1555 	if (dma_mapping_error(device->dev, unmap->addr[1]))
1556 		goto err_get_unmap;
1557 
1558 	unmap->from_cnt = 1;
1559 
1560 	txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1561 					     unmap->addr[0], len,
1562 					     DMA_PREP_INTERRUPT);
1563 	if (!txd)
1564 		goto err_get_unmap;
1565 
1566 	txd->callback_result = ntb_rx_copy_callback;
1567 	txd->callback_param = entry;
1568 	dma_set_unmap(txd, unmap);
1569 
1570 	cookie = dmaengine_submit(txd);
1571 	if (dma_submit_error(cookie))
1572 		goto err_set_unmap;
1573 
1574 	dmaengine_unmap_put(unmap);
1575 
1576 	qp->last_cookie = cookie;
1577 
1578 	qp->rx_async++;
1579 
1580 	return 0;
1581 
1582 err_set_unmap:
1583 	dmaengine_unmap_put(unmap);
1584 err_get_unmap:
1585 	dmaengine_unmap_put(unmap);
1586 err:
1587 	return -ENXIO;
1588 }
1589 
1590 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1591 {
1592 	struct ntb_transport_qp *qp = entry->qp;
1593 	struct dma_chan *chan = qp->rx_dma_chan;
1594 	int res;
1595 
1596 	if (!chan)
1597 		goto err;
1598 
1599 	if (entry->len < copy_bytes)
1600 		goto err;
1601 
1602 	res = ntb_async_rx_submit(entry, offset);
1603 	if (res < 0)
1604 		goto err;
1605 
1606 	if (!entry->retries)
1607 		qp->rx_async++;
1608 
1609 	return;
1610 
1611 err:
1612 	ntb_memcpy_rx(entry, offset);
1613 	qp->rx_memcpy++;
1614 }
1615 
1616 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1617 {
1618 	struct ntb_payload_header *hdr;
1619 	struct ntb_queue_entry *entry;
1620 	void *offset;
1621 
1622 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1623 	hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1624 
1625 	dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1626 		qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1627 
1628 	if (!(hdr->flags & DESC_DONE_FLAG)) {
1629 		dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1630 		qp->rx_ring_empty++;
1631 		return -EAGAIN;
1632 	}
1633 
1634 	if (hdr->flags & LINK_DOWN_FLAG) {
1635 		dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1636 		ntb_qp_link_down(qp);
1637 		hdr->flags = 0;
1638 		return -EAGAIN;
1639 	}
1640 
1641 	if (hdr->ver != (u32)qp->rx_pkts) {
1642 		dev_dbg(&qp->ndev->pdev->dev,
1643 			"version mismatch, expected %llu - got %u\n",
1644 			qp->rx_pkts, hdr->ver);
1645 		qp->rx_err_ver++;
1646 		return -EIO;
1647 	}
1648 
1649 	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1650 	if (!entry) {
1651 		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1652 		qp->rx_err_no_buf++;
1653 		return -EAGAIN;
1654 	}
1655 
1656 	entry->rx_hdr = hdr;
1657 	entry->rx_index = qp->rx_index;
1658 
1659 	if (hdr->len > entry->len) {
1660 		dev_dbg(&qp->ndev->pdev->dev,
1661 			"receive buffer overflow! Wanted %d got %d\n",
1662 			hdr->len, entry->len);
1663 		qp->rx_err_oflow++;
1664 
1665 		entry->len = -EIO;
1666 		entry->flags |= DESC_DONE_FLAG;
1667 
1668 		ntb_complete_rxc(qp);
1669 	} else {
1670 		dev_dbg(&qp->ndev->pdev->dev,
1671 			"RX OK index %u ver %u size %d into buf size %d\n",
1672 			qp->rx_index, hdr->ver, hdr->len, entry->len);
1673 
1674 		qp->rx_bytes += hdr->len;
1675 		qp->rx_pkts++;
1676 
1677 		entry->len = hdr->len;
1678 
1679 		ntb_async_rx(entry, offset);
1680 	}
1681 
1682 	qp->rx_index++;
1683 	qp->rx_index %= qp->rx_max_entry;
1684 
1685 	return 0;
1686 }
1687 
1688 static void ntb_transport_rxc_db(unsigned long data)
1689 {
1690 	struct ntb_transport_qp *qp = (void *)data;
1691 	int rc, i;
1692 
1693 	dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1694 		__func__, qp->qp_num);
1695 
1696 	/* Limit the number of packets processed in a single interrupt to
1697 	 * provide fairness to others
1698 	 */
1699 	for (i = 0; i < qp->rx_max_entry; i++) {
1700 		rc = ntb_process_rxc(qp);
1701 		if (rc)
1702 			break;
1703 	}
1704 
1705 	if (i && qp->rx_dma_chan)
1706 		dma_async_issue_pending(qp->rx_dma_chan);
1707 
1708 	if (i == qp->rx_max_entry) {
1709 		/* there is more work to do */
1710 		if (qp->active)
1711 			tasklet_schedule(&qp->rxc_db_work);
1712 	} else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1713 		/* the doorbell bit is set: clear it */
1714 		ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1715 		/* ntb_db_read ensures ntb_db_clear write is committed */
1716 		ntb_db_read(qp->ndev);
1717 
1718 		/* an interrupt may have arrived between finishing
1719 		 * ntb_process_rxc and clearing the doorbell bit:
1720 		 * there might be some more work to do.
1721 		 */
1722 		if (qp->active)
1723 			tasklet_schedule(&qp->rxc_db_work);
1724 	}
1725 }
1726 
1727 static void ntb_tx_copy_callback(void *data,
1728 				 const struct dmaengine_result *res)
1729 {
1730 	struct ntb_queue_entry *entry = data;
1731 	struct ntb_transport_qp *qp = entry->qp;
1732 	struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1733 
1734 	/* we need to check DMA results if we are using DMA */
1735 	if (res) {
1736 		enum dmaengine_tx_result dma_err = res->result;
1737 
1738 		switch (dma_err) {
1739 		case DMA_TRANS_READ_FAILED:
1740 		case DMA_TRANS_WRITE_FAILED:
1741 			entry->errors++;
1742 			fallthrough;
1743 		case DMA_TRANS_ABORTED:
1744 		{
1745 			void __iomem *offset =
1746 				qp->tx_mw + qp->tx_max_frame *
1747 				entry->tx_index;
1748 
1749 			/* resubmit via CPU */
1750 			ntb_memcpy_tx(entry, offset);
1751 			qp->tx_memcpy++;
1752 			return;
1753 		}
1754 
1755 		case DMA_TRANS_NOERROR:
1756 		default:
1757 			break;
1758 		}
1759 	}
1760 
1761 	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1762 
1763 	if (qp->use_msi)
1764 		ntb_msi_peer_trigger(qp->ndev, PIDX, &qp->peer_msi_desc);
1765 	else
1766 		ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1767 
1768 	/* The entry length can only be zero if the packet is intended to be a
1769 	 * "link down" or similar.  Since no payload is being sent in these
1770 	 * cases, there is nothing to add to the completion queue.
1771 	 */
1772 	if (entry->len > 0) {
1773 		qp->tx_bytes += entry->len;
1774 
1775 		if (qp->tx_handler)
1776 			qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1777 				       entry->len);
1778 	}
1779 
1780 	ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1781 }
1782 
1783 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1784 {
1785 #ifdef ARCH_HAS_NOCACHE_UACCESS
1786 	/*
1787 	 * Using non-temporal mov to improve performance on non-cached
1788 	 * writes, even though we aren't actually copying from user space.
1789 	 */
1790 	__copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1791 #else
1792 	memcpy_toio(offset, entry->buf, entry->len);
1793 #endif
1794 
1795 	/* Ensure that the data is fully copied out before setting the flags */
1796 	wmb();
1797 
1798 	ntb_tx_copy_callback(entry, NULL);
1799 }
1800 
1801 static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
1802 			       struct ntb_queue_entry *entry)
1803 {
1804 	struct dma_async_tx_descriptor *txd;
1805 	struct dma_chan *chan = qp->tx_dma_chan;
1806 	struct dma_device *device;
1807 	size_t len = entry->len;
1808 	void *buf = entry->buf;
1809 	size_t dest_off, buff_off;
1810 	struct dmaengine_unmap_data *unmap;
1811 	dma_addr_t dest;
1812 	dma_cookie_t cookie;
1813 
1814 	device = chan->device;
1815 	dest = qp->tx_mw_dma_addr + qp->tx_max_frame * entry->tx_index;
1816 	buff_off = (size_t)buf & ~PAGE_MASK;
1817 	dest_off = (size_t)dest & ~PAGE_MASK;
1818 
1819 	if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1820 		goto err;
1821 
1822 	unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1823 	if (!unmap)
1824 		goto err;
1825 
1826 	unmap->len = len;
1827 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1828 				      buff_off, len, DMA_TO_DEVICE);
1829 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1830 		goto err_get_unmap;
1831 
1832 	unmap->to_cnt = 1;
1833 
1834 	txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1835 					     DMA_PREP_INTERRUPT);
1836 	if (!txd)
1837 		goto err_get_unmap;
1838 
1839 	txd->callback_result = ntb_tx_copy_callback;
1840 	txd->callback_param = entry;
1841 	dma_set_unmap(txd, unmap);
1842 
1843 	cookie = dmaengine_submit(txd);
1844 	if (dma_submit_error(cookie))
1845 		goto err_set_unmap;
1846 
1847 	dmaengine_unmap_put(unmap);
1848 
1849 	dma_async_issue_pending(chan);
1850 
1851 	return 0;
1852 err_set_unmap:
1853 	dmaengine_unmap_put(unmap);
1854 err_get_unmap:
1855 	dmaengine_unmap_put(unmap);
1856 err:
1857 	return -ENXIO;
1858 }
1859 
1860 static void ntb_async_tx(struct ntb_transport_qp *qp,
1861 			 struct ntb_queue_entry *entry)
1862 {
1863 	struct ntb_payload_header __iomem *hdr;
1864 	struct dma_chan *chan = qp->tx_dma_chan;
1865 	void __iomem *offset;
1866 	int res;
1867 
1868 	entry->tx_index = qp->tx_index;
1869 	offset = qp->tx_mw + qp->tx_max_frame * entry->tx_index;
1870 	hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1871 	entry->tx_hdr = hdr;
1872 
1873 	iowrite32(entry->len, &hdr->len);
1874 	iowrite32((u32)qp->tx_pkts, &hdr->ver);
1875 
1876 	if (!chan)
1877 		goto err;
1878 
1879 	if (entry->len < copy_bytes)
1880 		goto err;
1881 
1882 	res = ntb_async_tx_submit(qp, entry);
1883 	if (res < 0)
1884 		goto err;
1885 
1886 	if (!entry->retries)
1887 		qp->tx_async++;
1888 
1889 	return;
1890 
1891 err:
1892 	ntb_memcpy_tx(entry, offset);
1893 	qp->tx_memcpy++;
1894 }
1895 
1896 static int ntb_process_tx(struct ntb_transport_qp *qp,
1897 			  struct ntb_queue_entry *entry)
1898 {
1899 	if (qp->tx_index == qp->remote_rx_info->entry) {
1900 		qp->tx_ring_full++;
1901 		return -EAGAIN;
1902 	}
1903 
1904 	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1905 		if (qp->tx_handler)
1906 			qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
1907 
1908 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1909 			     &qp->tx_free_q);
1910 		return 0;
1911 	}
1912 
1913 	ntb_async_tx(qp, entry);
1914 
1915 	qp->tx_index++;
1916 	qp->tx_index %= qp->tx_max_entry;
1917 
1918 	qp->tx_pkts++;
1919 
1920 	return 0;
1921 }
1922 
1923 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1924 {
1925 	struct pci_dev *pdev = qp->ndev->pdev;
1926 	struct ntb_queue_entry *entry;
1927 	int i, rc;
1928 
1929 	if (!qp->link_is_up)
1930 		return;
1931 
1932 	dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1933 
1934 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1935 		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1936 		if (entry)
1937 			break;
1938 		msleep(100);
1939 	}
1940 
1941 	if (!entry)
1942 		return;
1943 
1944 	entry->cb_data = NULL;
1945 	entry->buf = NULL;
1946 	entry->len = 0;
1947 	entry->flags = LINK_DOWN_FLAG;
1948 
1949 	rc = ntb_process_tx(qp, entry);
1950 	if (rc)
1951 		dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1952 			qp->qp_num);
1953 
1954 	ntb_qp_link_down_reset(qp);
1955 }
1956 
1957 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1958 {
1959 	return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1960 }
1961 
1962 /**
1963  * ntb_transport_create_queue - Create a new NTB transport layer queue
1964  * @rx_handler: receive callback function
1965  * @tx_handler: transmit callback function
1966  * @event_handler: event callback function
1967  *
1968  * Create a new NTB transport layer queue and provide the queue with a callback
1969  * routine for both transmit and receive.  The receive callback routine will be
1970  * used to pass up data when the transport has received it on the queue.   The
1971  * transmit callback routine will be called when the transport has completed the
1972  * transmission of the data on the queue and the data is ready to be freed.
1973  *
1974  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1975  */
1976 struct ntb_transport_qp *
1977 ntb_transport_create_queue(void *data, struct device *client_dev,
1978 			   const struct ntb_queue_handlers *handlers)
1979 {
1980 	struct ntb_dev *ndev;
1981 	struct pci_dev *pdev;
1982 	struct ntb_transport_ctx *nt;
1983 	struct ntb_queue_entry *entry;
1984 	struct ntb_transport_qp *qp;
1985 	u64 qp_bit;
1986 	unsigned int free_queue;
1987 	dma_cap_mask_t dma_mask;
1988 	int node;
1989 	int i;
1990 
1991 	ndev = dev_ntb(client_dev->parent);
1992 	pdev = ndev->pdev;
1993 	nt = ndev->ctx;
1994 
1995 	node = dev_to_node(&ndev->dev);
1996 
1997 	free_queue = ffs(nt->qp_bitmap_free);
1998 	if (!free_queue)
1999 		goto err;
2000 
2001 	/* decrement free_queue to make it zero based */
2002 	free_queue--;
2003 
2004 	qp = &nt->qp_vec[free_queue];
2005 	qp_bit = BIT_ULL(qp->qp_num);
2006 
2007 	nt->qp_bitmap_free &= ~qp_bit;
2008 
2009 	qp->cb_data = data;
2010 	qp->rx_handler = handlers->rx_handler;
2011 	qp->tx_handler = handlers->tx_handler;
2012 	qp->event_handler = handlers->event_handler;
2013 
2014 	dma_cap_zero(dma_mask);
2015 	dma_cap_set(DMA_MEMCPY, dma_mask);
2016 
2017 	if (use_dma) {
2018 		qp->tx_dma_chan =
2019 			dma_request_channel(dma_mask, ntb_dma_filter_fn,
2020 					    (void *)(unsigned long)node);
2021 		if (!qp->tx_dma_chan)
2022 			dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
2023 
2024 		qp->rx_dma_chan =
2025 			dma_request_channel(dma_mask, ntb_dma_filter_fn,
2026 					    (void *)(unsigned long)node);
2027 		if (!qp->rx_dma_chan)
2028 			dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
2029 	} else {
2030 		qp->tx_dma_chan = NULL;
2031 		qp->rx_dma_chan = NULL;
2032 	}
2033 
2034 	qp->tx_mw_dma_addr = 0;
2035 	if (qp->tx_dma_chan) {
2036 		qp->tx_mw_dma_addr =
2037 			dma_map_resource(qp->tx_dma_chan->device->dev,
2038 					 qp->tx_mw_phys, qp->tx_mw_size,
2039 					 DMA_FROM_DEVICE, 0);
2040 		if (dma_mapping_error(qp->tx_dma_chan->device->dev,
2041 				      qp->tx_mw_dma_addr)) {
2042 			qp->tx_mw_dma_addr = 0;
2043 			goto err1;
2044 		}
2045 	}
2046 
2047 	dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
2048 		qp->tx_dma_chan ? "DMA" : "CPU");
2049 
2050 	dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
2051 		qp->rx_dma_chan ? "DMA" : "CPU");
2052 
2053 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
2054 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
2055 		if (!entry)
2056 			goto err1;
2057 
2058 		entry->qp = qp;
2059 		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
2060 			     &qp->rx_free_q);
2061 	}
2062 	qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;
2063 
2064 	for (i = 0; i < qp->tx_max_entry; i++) {
2065 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
2066 		if (!entry)
2067 			goto err2;
2068 
2069 		entry->qp = qp;
2070 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
2071 			     &qp->tx_free_q);
2072 	}
2073 
2074 	ntb_db_clear(qp->ndev, qp_bit);
2075 	ntb_db_clear_mask(qp->ndev, qp_bit);
2076 
2077 	dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
2078 
2079 	return qp;
2080 
2081 err2:
2082 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
2083 		kfree(entry);
2084 err1:
2085 	qp->rx_alloc_entry = 0;
2086 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
2087 		kfree(entry);
2088 	if (qp->tx_mw_dma_addr)
2089 		dma_unmap_resource(qp->tx_dma_chan->device->dev,
2090 				   qp->tx_mw_dma_addr, qp->tx_mw_size,
2091 				   DMA_FROM_DEVICE, 0);
2092 	if (qp->tx_dma_chan)
2093 		dma_release_channel(qp->tx_dma_chan);
2094 	if (qp->rx_dma_chan)
2095 		dma_release_channel(qp->rx_dma_chan);
2096 	nt->qp_bitmap_free |= qp_bit;
2097 err:
2098 	return NULL;
2099 }
2100 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
2101 
2102 /**
2103  * ntb_transport_free_queue - Frees NTB transport queue
2104  * @qp: NTB queue to be freed
2105  *
2106  * Frees NTB transport queue
2107  */
2108 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
2109 {
2110 	struct pci_dev *pdev;
2111 	struct ntb_queue_entry *entry;
2112 	u64 qp_bit;
2113 
2114 	if (!qp)
2115 		return;
2116 
2117 	pdev = qp->ndev->pdev;
2118 
2119 	qp->active = false;
2120 
2121 	if (qp->tx_dma_chan) {
2122 		struct dma_chan *chan = qp->tx_dma_chan;
2123 		/* Putting the dma_chan to NULL will force any new traffic to be
2124 		 * processed by the CPU instead of the DAM engine
2125 		 */
2126 		qp->tx_dma_chan = NULL;
2127 
2128 		/* Try to be nice and wait for any queued DMA engine
2129 		 * transactions to process before smashing it with a rock
2130 		 */
2131 		dma_sync_wait(chan, qp->last_cookie);
2132 		dmaengine_terminate_all(chan);
2133 
2134 		dma_unmap_resource(chan->device->dev,
2135 				   qp->tx_mw_dma_addr, qp->tx_mw_size,
2136 				   DMA_FROM_DEVICE, 0);
2137 
2138 		dma_release_channel(chan);
2139 	}
2140 
2141 	if (qp->rx_dma_chan) {
2142 		struct dma_chan *chan = qp->rx_dma_chan;
2143 		/* Putting the dma_chan to NULL will force any new traffic to be
2144 		 * processed by the CPU instead of the DAM engine
2145 		 */
2146 		qp->rx_dma_chan = NULL;
2147 
2148 		/* Try to be nice and wait for any queued DMA engine
2149 		 * transactions to process before smashing it with a rock
2150 		 */
2151 		dma_sync_wait(chan, qp->last_cookie);
2152 		dmaengine_terminate_all(chan);
2153 		dma_release_channel(chan);
2154 	}
2155 
2156 	qp_bit = BIT_ULL(qp->qp_num);
2157 
2158 	ntb_db_set_mask(qp->ndev, qp_bit);
2159 	tasklet_kill(&qp->rxc_db_work);
2160 
2161 	cancel_delayed_work_sync(&qp->link_work);
2162 
2163 	qp->cb_data = NULL;
2164 	qp->rx_handler = NULL;
2165 	qp->tx_handler = NULL;
2166 	qp->event_handler = NULL;
2167 
2168 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
2169 		kfree(entry);
2170 
2171 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
2172 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
2173 		kfree(entry);
2174 	}
2175 
2176 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
2177 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
2178 		kfree(entry);
2179 	}
2180 
2181 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
2182 		kfree(entry);
2183 
2184 	qp->transport->qp_bitmap_free |= qp_bit;
2185 
2186 	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
2187 }
2188 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
2189 
2190 /**
2191  * ntb_transport_rx_remove - Dequeues enqueued rx packet
2192  * @qp: NTB queue to be freed
2193  * @len: pointer to variable to write enqueued buffers length
2194  *
2195  * Dequeues unused buffers from receive queue.  Should only be used during
2196  * shutdown of qp.
2197  *
2198  * RETURNS: NULL error value on error, or void* for success.
2199  */
2200 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
2201 {
2202 	struct ntb_queue_entry *entry;
2203 	void *buf;
2204 
2205 	if (!qp || qp->client_ready)
2206 		return NULL;
2207 
2208 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
2209 	if (!entry)
2210 		return NULL;
2211 
2212 	buf = entry->cb_data;
2213 	*len = entry->len;
2214 
2215 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
2216 
2217 	return buf;
2218 }
2219 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
2220 
2221 /**
2222  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
2223  * @qp: NTB transport layer queue the entry is to be enqueued on
2224  * @cb: per buffer pointer for callback function to use
2225  * @data: pointer to data buffer that incoming packets will be copied into
2226  * @len: length of the data buffer
2227  *
2228  * Enqueue a new receive buffer onto the transport queue into which a NTB
2229  * payload can be received into.
2230  *
2231  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
2232  */
2233 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
2234 			     unsigned int len)
2235 {
2236 	struct ntb_queue_entry *entry;
2237 
2238 	if (!qp)
2239 		return -EINVAL;
2240 
2241 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
2242 	if (!entry)
2243 		return -ENOMEM;
2244 
2245 	entry->cb_data = cb;
2246 	entry->buf = data;
2247 	entry->len = len;
2248 	entry->flags = 0;
2249 	entry->retries = 0;
2250 	entry->errors = 0;
2251 	entry->rx_index = 0;
2252 
2253 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
2254 
2255 	if (qp->active)
2256 		tasklet_schedule(&qp->rxc_db_work);
2257 
2258 	return 0;
2259 }
2260 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
2261 
2262 /**
2263  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
2264  * @qp: NTB transport layer queue the entry is to be enqueued on
2265  * @cb: per buffer pointer for callback function to use
2266  * @data: pointer to data buffer that will be sent
2267  * @len: length of the data buffer
2268  *
2269  * Enqueue a new transmit buffer onto the transport queue from which a NTB
2270  * payload will be transmitted.  This assumes that a lock is being held to
2271  * serialize access to the qp.
2272  *
2273  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
2274  */
2275 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
2276 			     unsigned int len)
2277 {
2278 	struct ntb_queue_entry *entry;
2279 	int rc;
2280 
2281 	if (!qp || !qp->link_is_up || !len)
2282 		return -EINVAL;
2283 
2284 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
2285 	if (!entry) {
2286 		qp->tx_err_no_buf++;
2287 		return -EBUSY;
2288 	}
2289 
2290 	entry->cb_data = cb;
2291 	entry->buf = data;
2292 	entry->len = len;
2293 	entry->flags = 0;
2294 	entry->errors = 0;
2295 	entry->retries = 0;
2296 	entry->tx_index = 0;
2297 
2298 	rc = ntb_process_tx(qp, entry);
2299 	if (rc)
2300 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
2301 			     &qp->tx_free_q);
2302 
2303 	return rc;
2304 }
2305 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
2306 
2307 /**
2308  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
2309  * @qp: NTB transport layer queue to be enabled
2310  *
2311  * Notify NTB transport layer of client readiness to use queue
2312  */
2313 void ntb_transport_link_up(struct ntb_transport_qp *qp)
2314 {
2315 	if (!qp)
2316 		return;
2317 
2318 	qp->client_ready = true;
2319 
2320 	if (qp->transport->link_is_up)
2321 		schedule_delayed_work(&qp->link_work, 0);
2322 }
2323 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
2324 
2325 /**
2326  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
2327  * @qp: NTB transport layer queue to be disabled
2328  *
2329  * Notify NTB transport layer of client's desire to no longer receive data on
2330  * transport queue specified.  It is the client's responsibility to ensure all
2331  * entries on queue are purged or otherwise handled appropriately.
2332  */
2333 void ntb_transport_link_down(struct ntb_transport_qp *qp)
2334 {
2335 	int val;
2336 
2337 	if (!qp)
2338 		return;
2339 
2340 	qp->client_ready = false;
2341 
2342 	val = ntb_spad_read(qp->ndev, QP_LINKS);
2343 
2344 	ntb_peer_spad_write(qp->ndev, PIDX, QP_LINKS, val & ~BIT(qp->qp_num));
2345 
2346 	if (qp->link_is_up)
2347 		ntb_send_link_down(qp);
2348 	else
2349 		cancel_delayed_work_sync(&qp->link_work);
2350 }
2351 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
2352 
2353 /**
2354  * ntb_transport_link_query - Query transport link state
2355  * @qp: NTB transport layer queue to be queried
2356  *
2357  * Query connectivity to the remote system of the NTB transport queue
2358  *
2359  * RETURNS: true for link up or false for link down
2360  */
2361 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
2362 {
2363 	if (!qp)
2364 		return false;
2365 
2366 	return qp->link_is_up;
2367 }
2368 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
2369 
2370 /**
2371  * ntb_transport_qp_num - Query the qp number
2372  * @qp: NTB transport layer queue to be queried
2373  *
2374  * Query qp number of the NTB transport queue
2375  *
2376  * RETURNS: a zero based number specifying the qp number
2377  */
2378 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
2379 {
2380 	if (!qp)
2381 		return 0;
2382 
2383 	return qp->qp_num;
2384 }
2385 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
2386 
2387 /**
2388  * ntb_transport_max_size - Query the max payload size of a qp
2389  * @qp: NTB transport layer queue to be queried
2390  *
2391  * Query the maximum payload size permissible on the given qp
2392  *
2393  * RETURNS: the max payload size of a qp
2394  */
2395 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
2396 {
2397 	unsigned int max_size;
2398 	unsigned int copy_align;
2399 	struct dma_chan *rx_chan, *tx_chan;
2400 
2401 	if (!qp)
2402 		return 0;
2403 
2404 	rx_chan = qp->rx_dma_chan;
2405 	tx_chan = qp->tx_dma_chan;
2406 
2407 	copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
2408 			 tx_chan ? tx_chan->device->copy_align : 0);
2409 
2410 	/* If DMA engine usage is possible, try to find the max size for that */
2411 	max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
2412 	max_size = round_down(max_size, 1 << copy_align);
2413 
2414 	return max_size;
2415 }
2416 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
2417 
2418 unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
2419 {
2420 	unsigned int head = qp->tx_index;
2421 	unsigned int tail = qp->remote_rx_info->entry;
2422 
2423 	return tail > head ? tail - head : qp->tx_max_entry + tail - head;
2424 }
2425 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
2426 
2427 static void ntb_transport_doorbell_callback(void *data, int vector)
2428 {
2429 	struct ntb_transport_ctx *nt = data;
2430 	struct ntb_transport_qp *qp;
2431 	u64 db_bits;
2432 	unsigned int qp_num;
2433 
2434 	if (ntb_db_read(nt->ndev) & nt->msi_db_mask) {
2435 		ntb_transport_msi_peer_desc_changed(nt);
2436 		ntb_db_clear(nt->ndev, nt->msi_db_mask);
2437 	}
2438 
2439 	db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
2440 		   ntb_db_vector_mask(nt->ndev, vector));
2441 
2442 	while (db_bits) {
2443 		qp_num = __ffs(db_bits);
2444 		qp = &nt->qp_vec[qp_num];
2445 
2446 		if (qp->active)
2447 			tasklet_schedule(&qp->rxc_db_work);
2448 
2449 		db_bits &= ~BIT_ULL(qp_num);
2450 	}
2451 }
2452 
2453 static const struct ntb_ctx_ops ntb_transport_ops = {
2454 	.link_event = ntb_transport_event_callback,
2455 	.db_event = ntb_transport_doorbell_callback,
2456 };
2457 
2458 static struct ntb_client ntb_transport_client = {
2459 	.ops = {
2460 		.probe = ntb_transport_probe,
2461 		.remove = ntb_transport_free,
2462 	},
2463 };
2464 
2465 static int __init ntb_transport_init(void)
2466 {
2467 	int rc;
2468 
2469 	pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2470 
2471 	if (debugfs_initialized())
2472 		nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2473 
2474 	rc = bus_register(&ntb_transport_bus);
2475 	if (rc)
2476 		goto err_bus;
2477 
2478 	rc = ntb_register_client(&ntb_transport_client);
2479 	if (rc)
2480 		goto err_client;
2481 
2482 	return 0;
2483 
2484 err_client:
2485 	bus_unregister(&ntb_transport_bus);
2486 err_bus:
2487 	debugfs_remove_recursive(nt_debugfs_dir);
2488 	return rc;
2489 }
2490 module_init(ntb_transport_init);
2491 
2492 static void __exit ntb_transport_exit(void)
2493 {
2494 	ntb_unregister_client(&ntb_transport_client);
2495 	bus_unregister(&ntb_transport_bus);
2496 	debugfs_remove_recursive(nt_debugfs_dir);
2497 }
2498 module_exit(ntb_transport_exit);
2499