xref: /openbmc/linux/drivers/ntb/ntb_transport.c (revision fe4549b1)
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 void 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 
317 static struct bus_type ntb_transport_bus = {
318 	.name = "ntb_transport",
319 	.match = ntb_transport_bus_match,
320 	.probe = ntb_transport_bus_probe,
321 	.remove = ntb_transport_bus_remove,
322 };
323 
324 static LIST_HEAD(ntb_transport_list);
325 
326 static int ntb_bus_init(struct ntb_transport_ctx *nt)
327 {
328 	list_add_tail(&nt->entry, &ntb_transport_list);
329 	return 0;
330 }
331 
332 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
333 {
334 	struct ntb_transport_client_dev *client_dev, *cd;
335 
336 	list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
337 		dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
338 			dev_name(&client_dev->dev));
339 		list_del(&client_dev->entry);
340 		device_unregister(&client_dev->dev);
341 	}
342 
343 	list_del(&nt->entry);
344 }
345 
346 static void ntb_transport_client_release(struct device *dev)
347 {
348 	struct ntb_transport_client_dev *client_dev;
349 
350 	client_dev = dev_client_dev(dev);
351 	kfree(client_dev);
352 }
353 
354 /**
355  * ntb_transport_unregister_client_dev - Unregister NTB client device
356  * @device_name: Name of NTB client device
357  *
358  * Unregister an NTB client device with the NTB transport layer
359  */
360 void ntb_transport_unregister_client_dev(char *device_name)
361 {
362 	struct ntb_transport_client_dev *client, *cd;
363 	struct ntb_transport_ctx *nt;
364 
365 	list_for_each_entry(nt, &ntb_transport_list, entry)
366 		list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
367 			if (!strncmp(dev_name(&client->dev), device_name,
368 				     strlen(device_name))) {
369 				list_del(&client->entry);
370 				device_unregister(&client->dev);
371 			}
372 }
373 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
374 
375 /**
376  * ntb_transport_register_client_dev - Register NTB client device
377  * @device_name: Name of NTB client device
378  *
379  * Register an NTB client device with the NTB transport layer
380  */
381 int ntb_transport_register_client_dev(char *device_name)
382 {
383 	struct ntb_transport_client_dev *client_dev;
384 	struct ntb_transport_ctx *nt;
385 	int node;
386 	int rc, i = 0;
387 
388 	if (list_empty(&ntb_transport_list))
389 		return -ENODEV;
390 
391 	list_for_each_entry(nt, &ntb_transport_list, entry) {
392 		struct device *dev;
393 
394 		node = dev_to_node(&nt->ndev->dev);
395 
396 		client_dev = kzalloc_node(sizeof(*client_dev),
397 					  GFP_KERNEL, node);
398 		if (!client_dev) {
399 			rc = -ENOMEM;
400 			goto err;
401 		}
402 
403 		dev = &client_dev->dev;
404 
405 		/* setup and register client devices */
406 		dev_set_name(dev, "%s%d", device_name, i);
407 		dev->bus = &ntb_transport_bus;
408 		dev->release = ntb_transport_client_release;
409 		dev->parent = &nt->ndev->dev;
410 
411 		rc = device_register(dev);
412 		if (rc) {
413 			put_device(dev);
414 			goto err;
415 		}
416 
417 		list_add_tail(&client_dev->entry, &nt->client_devs);
418 		i++;
419 	}
420 
421 	return 0;
422 
423 err:
424 	ntb_transport_unregister_client_dev(device_name);
425 
426 	return rc;
427 }
428 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
429 
430 /**
431  * ntb_transport_register_client - Register NTB client driver
432  * @drv: NTB client driver to be registered
433  *
434  * Register an NTB client driver with the NTB transport layer
435  *
436  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
437  */
438 int ntb_transport_register_client(struct ntb_transport_client *drv)
439 {
440 	drv->driver.bus = &ntb_transport_bus;
441 
442 	if (list_empty(&ntb_transport_list))
443 		return -ENODEV;
444 
445 	return driver_register(&drv->driver);
446 }
447 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
448 
449 /**
450  * ntb_transport_unregister_client - Unregister NTB client driver
451  * @drv: NTB client driver to be unregistered
452  *
453  * Unregister an NTB client driver with the NTB transport layer
454  *
455  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
456  */
457 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
458 {
459 	driver_unregister(&drv->driver);
460 }
461 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
462 
463 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
464 			    loff_t *offp)
465 {
466 	struct ntb_transport_qp *qp;
467 	char *buf;
468 	ssize_t ret, out_offset, out_count;
469 
470 	qp = filp->private_data;
471 
472 	if (!qp || !qp->link_is_up)
473 		return 0;
474 
475 	out_count = 1000;
476 
477 	buf = kmalloc(out_count, GFP_KERNEL);
478 	if (!buf)
479 		return -ENOMEM;
480 
481 	out_offset = 0;
482 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
483 			       "\nNTB QP stats:\n\n");
484 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
485 			       "rx_bytes - \t%llu\n", qp->rx_bytes);
486 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
487 			       "rx_pkts - \t%llu\n", qp->rx_pkts);
488 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
489 			       "rx_memcpy - \t%llu\n", qp->rx_memcpy);
490 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
491 			       "rx_async - \t%llu\n", qp->rx_async);
492 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
493 			       "rx_ring_empty - %llu\n", qp->rx_ring_empty);
494 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
495 			       "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
496 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
497 			       "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
498 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
499 			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
500 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
501 			       "rx_buff - \t0x%p\n", qp->rx_buff);
502 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
503 			       "rx_index - \t%u\n", qp->rx_index);
504 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
505 			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
506 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
507 			       "rx_alloc_entry - \t%u\n\n", qp->rx_alloc_entry);
508 
509 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
510 			       "tx_bytes - \t%llu\n", qp->tx_bytes);
511 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
512 			       "tx_pkts - \t%llu\n", qp->tx_pkts);
513 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
514 			       "tx_memcpy - \t%llu\n", qp->tx_memcpy);
515 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
516 			       "tx_async - \t%llu\n", qp->tx_async);
517 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
518 			       "tx_ring_full - \t%llu\n", qp->tx_ring_full);
519 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
520 			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
521 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
522 			       "tx_mw - \t0x%p\n", qp->tx_mw);
523 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
524 			       "tx_index (H) - \t%u\n", qp->tx_index);
525 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
526 			       "RRI (T) - \t%u\n",
527 			       qp->remote_rx_info->entry);
528 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
529 			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
530 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
531 			       "free tx - \t%u\n",
532 			       ntb_transport_tx_free_entry(qp));
533 
534 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
535 			       "\n");
536 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
537 			       "Using TX DMA - \t%s\n",
538 			       qp->tx_dma_chan ? "Yes" : "No");
539 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
540 			       "Using RX DMA - \t%s\n",
541 			       qp->rx_dma_chan ? "Yes" : "No");
542 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
543 			       "QP Link - \t%s\n",
544 			       qp->link_is_up ? "Up" : "Down");
545 	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
546 			       "\n");
547 
548 	if (out_offset > out_count)
549 		out_offset = out_count;
550 
551 	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
552 	kfree(buf);
553 	return ret;
554 }
555 
556 static const struct file_operations ntb_qp_debugfs_stats = {
557 	.owner = THIS_MODULE,
558 	.open = simple_open,
559 	.read = debugfs_read,
560 };
561 
562 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
563 			 struct list_head *list)
564 {
565 	unsigned long flags;
566 
567 	spin_lock_irqsave(lock, flags);
568 	list_add_tail(entry, list);
569 	spin_unlock_irqrestore(lock, flags);
570 }
571 
572 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
573 					   struct list_head *list)
574 {
575 	struct ntb_queue_entry *entry;
576 	unsigned long flags;
577 
578 	spin_lock_irqsave(lock, flags);
579 	if (list_empty(list)) {
580 		entry = NULL;
581 		goto out;
582 	}
583 	entry = list_first_entry(list, struct ntb_queue_entry, entry);
584 	list_del(&entry->entry);
585 
586 out:
587 	spin_unlock_irqrestore(lock, flags);
588 
589 	return entry;
590 }
591 
592 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
593 					   struct list_head *list,
594 					   struct list_head *to_list)
595 {
596 	struct ntb_queue_entry *entry;
597 	unsigned long flags;
598 
599 	spin_lock_irqsave(lock, flags);
600 
601 	if (list_empty(list)) {
602 		entry = NULL;
603 	} else {
604 		entry = list_first_entry(list, struct ntb_queue_entry, entry);
605 		list_move_tail(&entry->entry, to_list);
606 	}
607 
608 	spin_unlock_irqrestore(lock, flags);
609 
610 	return entry;
611 }
612 
613 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
614 				     unsigned int qp_num)
615 {
616 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
617 	struct ntb_transport_mw *mw;
618 	struct ntb_dev *ndev = nt->ndev;
619 	struct ntb_queue_entry *entry;
620 	unsigned int rx_size, num_qps_mw;
621 	unsigned int mw_num, mw_count, qp_count;
622 	unsigned int i;
623 	int node;
624 
625 	mw_count = nt->mw_count;
626 	qp_count = nt->qp_count;
627 
628 	mw_num = QP_TO_MW(nt, qp_num);
629 	mw = &nt->mw_vec[mw_num];
630 
631 	if (!mw->virt_addr)
632 		return -ENOMEM;
633 
634 	if (mw_num < qp_count % mw_count)
635 		num_qps_mw = qp_count / mw_count + 1;
636 	else
637 		num_qps_mw = qp_count / mw_count;
638 
639 	rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
640 	qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
641 	rx_size -= sizeof(struct ntb_rx_info);
642 
643 	qp->remote_rx_info = qp->rx_buff + rx_size;
644 
645 	/* Due to housekeeping, there must be atleast 2 buffs */
646 	qp->rx_max_frame = min(transport_mtu, rx_size / 2);
647 	qp->rx_max_entry = rx_size / qp->rx_max_frame;
648 	qp->rx_index = 0;
649 
650 	/*
651 	 * Checking to see if we have more entries than the default.
652 	 * We should add additional entries if that is the case so we
653 	 * can be in sync with the transport frames.
654 	 */
655 	node = dev_to_node(&ndev->dev);
656 	for (i = qp->rx_alloc_entry; i < qp->rx_max_entry; i++) {
657 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
658 		if (!entry)
659 			return -ENOMEM;
660 
661 		entry->qp = qp;
662 		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
663 			     &qp->rx_free_q);
664 		qp->rx_alloc_entry++;
665 	}
666 
667 	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
668 
669 	/* setup the hdr offsets with 0's */
670 	for (i = 0; i < qp->rx_max_entry; i++) {
671 		void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
672 				sizeof(struct ntb_payload_header));
673 		memset(offset, 0, sizeof(struct ntb_payload_header));
674 	}
675 
676 	qp->rx_pkts = 0;
677 	qp->tx_pkts = 0;
678 	qp->tx_index = 0;
679 
680 	return 0;
681 }
682 
683 static irqreturn_t ntb_transport_isr(int irq, void *dev)
684 {
685 	struct ntb_transport_qp *qp = dev;
686 
687 	tasklet_schedule(&qp->rxc_db_work);
688 
689 	return IRQ_HANDLED;
690 }
691 
692 static void ntb_transport_setup_qp_peer_msi(struct ntb_transport_ctx *nt,
693 					    unsigned int qp_num)
694 {
695 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
696 	int spad = qp_num * 2 + nt->msi_spad_offset;
697 
698 	if (!nt->use_msi)
699 		return;
700 
701 	if (spad >= ntb_spad_count(nt->ndev))
702 		return;
703 
704 	qp->peer_msi_desc.addr_offset =
705 		ntb_peer_spad_read(qp->ndev, PIDX, spad);
706 	qp->peer_msi_desc.data =
707 		ntb_peer_spad_read(qp->ndev, PIDX, spad + 1);
708 
709 	dev_dbg(&qp->ndev->pdev->dev, "QP%d Peer MSI addr=%x data=%x\n",
710 		qp_num, qp->peer_msi_desc.addr_offset, qp->peer_msi_desc.data);
711 
712 	if (qp->peer_msi_desc.addr_offset) {
713 		qp->use_msi = true;
714 		dev_info(&qp->ndev->pdev->dev,
715 			 "Using MSI interrupts for QP%d\n", qp_num);
716 	}
717 }
718 
719 static void ntb_transport_setup_qp_msi(struct ntb_transport_ctx *nt,
720 				       unsigned int qp_num)
721 {
722 	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
723 	int spad = qp_num * 2 + nt->msi_spad_offset;
724 	int rc;
725 
726 	if (!nt->use_msi)
727 		return;
728 
729 	if (spad >= ntb_spad_count(nt->ndev)) {
730 		dev_warn_once(&qp->ndev->pdev->dev,
731 			      "Not enough SPADS to use MSI interrupts\n");
732 		return;
733 	}
734 
735 	ntb_spad_write(qp->ndev, spad, 0);
736 	ntb_spad_write(qp->ndev, spad + 1, 0);
737 
738 	if (!qp->msi_irq) {
739 		qp->msi_irq = ntbm_msi_request_irq(qp->ndev, ntb_transport_isr,
740 						   KBUILD_MODNAME, qp,
741 						   &qp->msi_desc);
742 		if (qp->msi_irq < 0) {
743 			dev_warn(&qp->ndev->pdev->dev,
744 				 "Unable to allocate MSI interrupt for qp%d\n",
745 				 qp_num);
746 			return;
747 		}
748 	}
749 
750 	rc = ntb_spad_write(qp->ndev, spad, qp->msi_desc.addr_offset);
751 	if (rc)
752 		goto err_free_interrupt;
753 
754 	rc = ntb_spad_write(qp->ndev, spad + 1, qp->msi_desc.data);
755 	if (rc)
756 		goto err_free_interrupt;
757 
758 	dev_dbg(&qp->ndev->pdev->dev, "QP%d MSI %d addr=%x data=%x\n",
759 		qp_num, qp->msi_irq, qp->msi_desc.addr_offset,
760 		qp->msi_desc.data);
761 
762 	return;
763 
764 err_free_interrupt:
765 	devm_free_irq(&nt->ndev->dev, qp->msi_irq, qp);
766 }
767 
768 static void ntb_transport_msi_peer_desc_changed(struct ntb_transport_ctx *nt)
769 {
770 	int i;
771 
772 	dev_dbg(&nt->ndev->pdev->dev, "Peer MSI descriptors changed");
773 
774 	for (i = 0; i < nt->qp_count; i++)
775 		ntb_transport_setup_qp_peer_msi(nt, i);
776 }
777 
778 static void ntb_transport_msi_desc_changed(void *data)
779 {
780 	struct ntb_transport_ctx *nt = data;
781 	int i;
782 
783 	dev_dbg(&nt->ndev->pdev->dev, "MSI descriptors changed");
784 
785 	for (i = 0; i < nt->qp_count; i++)
786 		ntb_transport_setup_qp_msi(nt, i);
787 
788 	ntb_peer_db_set(nt->ndev, nt->msi_db_mask);
789 }
790 
791 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
792 {
793 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
794 	struct pci_dev *pdev = nt->ndev->pdev;
795 
796 	if (!mw->virt_addr)
797 		return;
798 
799 	ntb_mw_clear_trans(nt->ndev, PIDX, num_mw);
800 	dma_free_coherent(&pdev->dev, mw->alloc_size,
801 			  mw->alloc_addr, mw->dma_addr);
802 	mw->xlat_size = 0;
803 	mw->buff_size = 0;
804 	mw->alloc_size = 0;
805 	mw->alloc_addr = NULL;
806 	mw->virt_addr = NULL;
807 }
808 
809 static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
810 			       struct device *dma_dev, size_t align)
811 {
812 	dma_addr_t dma_addr;
813 	void *alloc_addr, *virt_addr;
814 	int rc;
815 
816 	alloc_addr = dma_alloc_coherent(dma_dev, mw->alloc_size,
817 					&dma_addr, GFP_KERNEL);
818 	if (!alloc_addr) {
819 		dev_err(dma_dev, "Unable to alloc MW buff of size %zu\n",
820 			mw->alloc_size);
821 		return -ENOMEM;
822 	}
823 	virt_addr = alloc_addr;
824 
825 	/*
826 	 * we must ensure that the memory address allocated is BAR size
827 	 * aligned in order for the XLAT register to take the value. This
828 	 * is a requirement of the hardware. It is recommended to setup CMA
829 	 * for BAR sizes equal or greater than 4MB.
830 	 */
831 	if (!IS_ALIGNED(dma_addr, align)) {
832 		if (mw->alloc_size > mw->buff_size) {
833 			virt_addr = PTR_ALIGN(alloc_addr, align);
834 			dma_addr = ALIGN(dma_addr, align);
835 		} else {
836 			rc = -ENOMEM;
837 			goto err;
838 		}
839 	}
840 
841 	mw->alloc_addr = alloc_addr;
842 	mw->virt_addr = virt_addr;
843 	mw->dma_addr = dma_addr;
844 
845 	return 0;
846 
847 err:
848 	dma_free_coherent(dma_dev, mw->alloc_size, alloc_addr, dma_addr);
849 
850 	return rc;
851 }
852 
853 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
854 		      resource_size_t size)
855 {
856 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
857 	struct pci_dev *pdev = nt->ndev->pdev;
858 	size_t xlat_size, buff_size;
859 	resource_size_t xlat_align;
860 	resource_size_t xlat_align_size;
861 	int rc;
862 
863 	if (!size)
864 		return -EINVAL;
865 
866 	rc = ntb_mw_get_align(nt->ndev, PIDX, num_mw, &xlat_align,
867 			      &xlat_align_size, NULL);
868 	if (rc)
869 		return rc;
870 
871 	xlat_size = round_up(size, xlat_align_size);
872 	buff_size = round_up(size, xlat_align);
873 
874 	/* No need to re-setup */
875 	if (mw->xlat_size == xlat_size)
876 		return 0;
877 
878 	if (mw->buff_size)
879 		ntb_free_mw(nt, num_mw);
880 
881 	/* Alloc memory for receiving data.  Must be aligned */
882 	mw->xlat_size = xlat_size;
883 	mw->buff_size = buff_size;
884 	mw->alloc_size = buff_size;
885 
886 	rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
887 	if (rc) {
888 		mw->alloc_size *= 2;
889 		rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
890 		if (rc) {
891 			dev_err(&pdev->dev,
892 				"Unable to alloc aligned MW buff\n");
893 			mw->xlat_size = 0;
894 			mw->buff_size = 0;
895 			mw->alloc_size = 0;
896 			return rc;
897 		}
898 	}
899 
900 	/* Notify HW the memory location of the receive buffer */
901 	rc = ntb_mw_set_trans(nt->ndev, PIDX, num_mw, mw->dma_addr,
902 			      mw->xlat_size);
903 	if (rc) {
904 		dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
905 		ntb_free_mw(nt, num_mw);
906 		return -EIO;
907 	}
908 
909 	return 0;
910 }
911 
912 static void ntb_qp_link_context_reset(struct ntb_transport_qp *qp)
913 {
914 	qp->link_is_up = false;
915 	qp->active = false;
916 
917 	qp->tx_index = 0;
918 	qp->rx_index = 0;
919 	qp->rx_bytes = 0;
920 	qp->rx_pkts = 0;
921 	qp->rx_ring_empty = 0;
922 	qp->rx_err_no_buf = 0;
923 	qp->rx_err_oflow = 0;
924 	qp->rx_err_ver = 0;
925 	qp->rx_memcpy = 0;
926 	qp->rx_async = 0;
927 	qp->tx_bytes = 0;
928 	qp->tx_pkts = 0;
929 	qp->tx_ring_full = 0;
930 	qp->tx_err_no_buf = 0;
931 	qp->tx_memcpy = 0;
932 	qp->tx_async = 0;
933 }
934 
935 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
936 {
937 	ntb_qp_link_context_reset(qp);
938 	if (qp->remote_rx_info)
939 		qp->remote_rx_info->entry = qp->rx_max_entry - 1;
940 }
941 
942 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
943 {
944 	struct ntb_transport_ctx *nt = qp->transport;
945 	struct pci_dev *pdev = nt->ndev->pdev;
946 
947 	dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
948 
949 	cancel_delayed_work_sync(&qp->link_work);
950 	ntb_qp_link_down_reset(qp);
951 
952 	if (qp->event_handler)
953 		qp->event_handler(qp->cb_data, qp->link_is_up);
954 }
955 
956 static void ntb_qp_link_cleanup_work(struct work_struct *work)
957 {
958 	struct ntb_transport_qp *qp = container_of(work,
959 						   struct ntb_transport_qp,
960 						   link_cleanup);
961 	struct ntb_transport_ctx *nt = qp->transport;
962 
963 	ntb_qp_link_cleanup(qp);
964 
965 	if (nt->link_is_up)
966 		schedule_delayed_work(&qp->link_work,
967 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
968 }
969 
970 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
971 {
972 	schedule_work(&qp->link_cleanup);
973 }
974 
975 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
976 {
977 	struct ntb_transport_qp *qp;
978 	u64 qp_bitmap_alloc;
979 	unsigned int i, count;
980 
981 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
982 
983 	/* Pass along the info to any clients */
984 	for (i = 0; i < nt->qp_count; i++)
985 		if (qp_bitmap_alloc & BIT_ULL(i)) {
986 			qp = &nt->qp_vec[i];
987 			ntb_qp_link_cleanup(qp);
988 			cancel_work_sync(&qp->link_cleanup);
989 			cancel_delayed_work_sync(&qp->link_work);
990 		}
991 
992 	if (!nt->link_is_up)
993 		cancel_delayed_work_sync(&nt->link_work);
994 
995 	for (i = 0; i < nt->mw_count; i++)
996 		ntb_free_mw(nt, i);
997 
998 	/* The scratchpad registers keep the values if the remote side
999 	 * goes down, blast them now to give them a sane value the next
1000 	 * time they are accessed
1001 	 */
1002 	count = ntb_spad_count(nt->ndev);
1003 	for (i = 0; i < count; i++)
1004 		ntb_spad_write(nt->ndev, i, 0);
1005 }
1006 
1007 static void ntb_transport_link_cleanup_work(struct work_struct *work)
1008 {
1009 	struct ntb_transport_ctx *nt =
1010 		container_of(work, struct ntb_transport_ctx, link_cleanup);
1011 
1012 	ntb_transport_link_cleanup(nt);
1013 }
1014 
1015 static void ntb_transport_event_callback(void *data)
1016 {
1017 	struct ntb_transport_ctx *nt = data;
1018 
1019 	if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
1020 		schedule_delayed_work(&nt->link_work, 0);
1021 	else
1022 		schedule_work(&nt->link_cleanup);
1023 }
1024 
1025 static void ntb_transport_link_work(struct work_struct *work)
1026 {
1027 	struct ntb_transport_ctx *nt =
1028 		container_of(work, struct ntb_transport_ctx, link_work.work);
1029 	struct ntb_dev *ndev = nt->ndev;
1030 	struct pci_dev *pdev = ndev->pdev;
1031 	resource_size_t size;
1032 	u32 val;
1033 	int rc = 0, i, spad;
1034 
1035 	/* send the local info, in the opposite order of the way we read it */
1036 
1037 	if (nt->use_msi) {
1038 		rc = ntb_msi_setup_mws(ndev);
1039 		if (rc) {
1040 			dev_warn(&pdev->dev,
1041 				 "Failed to register MSI memory window: %d\n",
1042 				 rc);
1043 			nt->use_msi = false;
1044 		}
1045 	}
1046 
1047 	for (i = 0; i < nt->qp_count; i++)
1048 		ntb_transport_setup_qp_msi(nt, i);
1049 
1050 	for (i = 0; i < nt->mw_count; i++) {
1051 		size = nt->mw_vec[i].phys_size;
1052 
1053 		if (max_mw_size && size > max_mw_size)
1054 			size = max_mw_size;
1055 
1056 		spad = MW0_SZ_HIGH + (i * 2);
1057 		ntb_peer_spad_write(ndev, PIDX, spad, upper_32_bits(size));
1058 
1059 		spad = MW0_SZ_LOW + (i * 2);
1060 		ntb_peer_spad_write(ndev, PIDX, spad, lower_32_bits(size));
1061 	}
1062 
1063 	ntb_peer_spad_write(ndev, PIDX, NUM_MWS, nt->mw_count);
1064 
1065 	ntb_peer_spad_write(ndev, PIDX, NUM_QPS, nt->qp_count);
1066 
1067 	ntb_peer_spad_write(ndev, PIDX, VERSION, NTB_TRANSPORT_VERSION);
1068 
1069 	/* Query the remote side for its info */
1070 	val = ntb_spad_read(ndev, VERSION);
1071 	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
1072 	if (val != NTB_TRANSPORT_VERSION)
1073 		goto out;
1074 
1075 	val = ntb_spad_read(ndev, NUM_QPS);
1076 	dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
1077 	if (val != nt->qp_count)
1078 		goto out;
1079 
1080 	val = ntb_spad_read(ndev, NUM_MWS);
1081 	dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
1082 	if (val != nt->mw_count)
1083 		goto out;
1084 
1085 	for (i = 0; i < nt->mw_count; i++) {
1086 		u64 val64;
1087 
1088 		val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
1089 		val64 = (u64)val << 32;
1090 
1091 		val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
1092 		val64 |= val;
1093 
1094 		dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
1095 
1096 		rc = ntb_set_mw(nt, i, val64);
1097 		if (rc)
1098 			goto out1;
1099 	}
1100 
1101 	nt->link_is_up = true;
1102 
1103 	for (i = 0; i < nt->qp_count; i++) {
1104 		struct ntb_transport_qp *qp = &nt->qp_vec[i];
1105 
1106 		ntb_transport_setup_qp_mw(nt, i);
1107 		ntb_transport_setup_qp_peer_msi(nt, i);
1108 
1109 		if (qp->client_ready)
1110 			schedule_delayed_work(&qp->link_work, 0);
1111 	}
1112 
1113 	return;
1114 
1115 out1:
1116 	for (i = 0; i < nt->mw_count; i++)
1117 		ntb_free_mw(nt, i);
1118 
1119 	/* if there's an actual failure, we should just bail */
1120 	if (rc < 0)
1121 		return;
1122 
1123 out:
1124 	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
1125 		schedule_delayed_work(&nt->link_work,
1126 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
1127 }
1128 
1129 static void ntb_qp_link_work(struct work_struct *work)
1130 {
1131 	struct ntb_transport_qp *qp = container_of(work,
1132 						   struct ntb_transport_qp,
1133 						   link_work.work);
1134 	struct pci_dev *pdev = qp->ndev->pdev;
1135 	struct ntb_transport_ctx *nt = qp->transport;
1136 	int val;
1137 
1138 	WARN_ON(!nt->link_is_up);
1139 
1140 	val = ntb_spad_read(nt->ndev, QP_LINKS);
1141 
1142 	ntb_peer_spad_write(nt->ndev, PIDX, QP_LINKS, val | BIT(qp->qp_num));
1143 
1144 	/* query remote spad for qp ready bits */
1145 	dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
1146 
1147 	/* See if the remote side is up */
1148 	if (val & BIT(qp->qp_num)) {
1149 		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
1150 		qp->link_is_up = true;
1151 		qp->active = true;
1152 
1153 		if (qp->event_handler)
1154 			qp->event_handler(qp->cb_data, qp->link_is_up);
1155 
1156 		if (qp->active)
1157 			tasklet_schedule(&qp->rxc_db_work);
1158 	} else if (nt->link_is_up)
1159 		schedule_delayed_work(&qp->link_work,
1160 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
1161 }
1162 
1163 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
1164 				    unsigned int qp_num)
1165 {
1166 	struct ntb_transport_qp *qp;
1167 	phys_addr_t mw_base;
1168 	resource_size_t mw_size;
1169 	unsigned int num_qps_mw, tx_size;
1170 	unsigned int mw_num, mw_count, qp_count;
1171 	u64 qp_offset;
1172 
1173 	mw_count = nt->mw_count;
1174 	qp_count = nt->qp_count;
1175 
1176 	mw_num = QP_TO_MW(nt, qp_num);
1177 
1178 	qp = &nt->qp_vec[qp_num];
1179 	qp->qp_num = qp_num;
1180 	qp->transport = nt;
1181 	qp->ndev = nt->ndev;
1182 	qp->client_ready = false;
1183 	qp->event_handler = NULL;
1184 	ntb_qp_link_context_reset(qp);
1185 
1186 	if (mw_num < qp_count % mw_count)
1187 		num_qps_mw = qp_count / mw_count + 1;
1188 	else
1189 		num_qps_mw = qp_count / mw_count;
1190 
1191 	mw_base = nt->mw_vec[mw_num].phys_addr;
1192 	mw_size = nt->mw_vec[mw_num].phys_size;
1193 
1194 	if (max_mw_size && mw_size > max_mw_size)
1195 		mw_size = max_mw_size;
1196 
1197 	tx_size = (unsigned int)mw_size / num_qps_mw;
1198 	qp_offset = tx_size * (qp_num / mw_count);
1199 
1200 	qp->tx_mw_size = tx_size;
1201 	qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
1202 	if (!qp->tx_mw)
1203 		return -EINVAL;
1204 
1205 	qp->tx_mw_phys = mw_base + qp_offset;
1206 	if (!qp->tx_mw_phys)
1207 		return -EINVAL;
1208 
1209 	tx_size -= sizeof(struct ntb_rx_info);
1210 	qp->rx_info = qp->tx_mw + tx_size;
1211 
1212 	/* Due to housekeeping, there must be atleast 2 buffs */
1213 	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
1214 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
1215 
1216 	if (nt->debugfs_node_dir) {
1217 		char debugfs_name[4];
1218 
1219 		snprintf(debugfs_name, 4, "qp%d", qp_num);
1220 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
1221 						     nt->debugfs_node_dir);
1222 
1223 		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
1224 							qp->debugfs_dir, qp,
1225 							&ntb_qp_debugfs_stats);
1226 	} else {
1227 		qp->debugfs_dir = NULL;
1228 		qp->debugfs_stats = NULL;
1229 	}
1230 
1231 	INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
1232 	INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
1233 
1234 	spin_lock_init(&qp->ntb_rx_q_lock);
1235 	spin_lock_init(&qp->ntb_tx_free_q_lock);
1236 
1237 	INIT_LIST_HEAD(&qp->rx_post_q);
1238 	INIT_LIST_HEAD(&qp->rx_pend_q);
1239 	INIT_LIST_HEAD(&qp->rx_free_q);
1240 	INIT_LIST_HEAD(&qp->tx_free_q);
1241 
1242 	tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
1243 		     (unsigned long)qp);
1244 
1245 	return 0;
1246 }
1247 
1248 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
1249 {
1250 	struct ntb_transport_ctx *nt;
1251 	struct ntb_transport_mw *mw;
1252 	unsigned int mw_count, qp_count, spad_count, max_mw_count_for_spads;
1253 	u64 qp_bitmap;
1254 	int node;
1255 	int rc, i;
1256 
1257 	mw_count = ntb_peer_mw_count(ndev);
1258 
1259 	if (!ndev->ops->mw_set_trans) {
1260 		dev_err(&ndev->dev, "Inbound MW based NTB API is required\n");
1261 		return -EINVAL;
1262 	}
1263 
1264 	if (ntb_db_is_unsafe(ndev))
1265 		dev_dbg(&ndev->dev,
1266 			"doorbell is unsafe, proceed anyway...\n");
1267 	if (ntb_spad_is_unsafe(ndev))
1268 		dev_dbg(&ndev->dev,
1269 			"scratchpad is unsafe, proceed anyway...\n");
1270 
1271 	if (ntb_peer_port_count(ndev) != NTB_DEF_PEER_CNT)
1272 		dev_warn(&ndev->dev, "Multi-port NTB devices unsupported\n");
1273 
1274 	node = dev_to_node(&ndev->dev);
1275 
1276 	nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1277 	if (!nt)
1278 		return -ENOMEM;
1279 
1280 	nt->ndev = ndev;
1281 
1282 	/*
1283 	 * If we are using MSI, and have at least one extra memory window,
1284 	 * we will reserve the last MW for the MSI window.
1285 	 */
1286 	if (use_msi && mw_count > 1) {
1287 		rc = ntb_msi_init(ndev, ntb_transport_msi_desc_changed);
1288 		if (!rc) {
1289 			mw_count -= 1;
1290 			nt->use_msi = true;
1291 		}
1292 	}
1293 
1294 	spad_count = ntb_spad_count(ndev);
1295 
1296 	/* Limit the MW's based on the availability of scratchpads */
1297 
1298 	if (spad_count < NTB_TRANSPORT_MIN_SPADS) {
1299 		nt->mw_count = 0;
1300 		rc = -EINVAL;
1301 		goto err;
1302 	}
1303 
1304 	max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
1305 	nt->mw_count = min(mw_count, max_mw_count_for_spads);
1306 
1307 	nt->msi_spad_offset = nt->mw_count * 2 + MW0_SZ_HIGH;
1308 
1309 	nt->mw_vec = kcalloc_node(mw_count, sizeof(*nt->mw_vec),
1310 				  GFP_KERNEL, node);
1311 	if (!nt->mw_vec) {
1312 		rc = -ENOMEM;
1313 		goto err;
1314 	}
1315 
1316 	for (i = 0; i < mw_count; i++) {
1317 		mw = &nt->mw_vec[i];
1318 
1319 		rc = ntb_peer_mw_get_addr(ndev, i, &mw->phys_addr,
1320 					  &mw->phys_size);
1321 		if (rc)
1322 			goto err1;
1323 
1324 		mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1325 		if (!mw->vbase) {
1326 			rc = -ENOMEM;
1327 			goto err1;
1328 		}
1329 
1330 		mw->buff_size = 0;
1331 		mw->xlat_size = 0;
1332 		mw->virt_addr = NULL;
1333 		mw->dma_addr = 0;
1334 	}
1335 
1336 	qp_bitmap = ntb_db_valid_mask(ndev);
1337 
1338 	qp_count = ilog2(qp_bitmap);
1339 	if (nt->use_msi) {
1340 		qp_count -= 1;
1341 		nt->msi_db_mask = 1 << qp_count;
1342 		ntb_db_clear_mask(ndev, nt->msi_db_mask);
1343 	}
1344 
1345 	if (max_num_clients && max_num_clients < qp_count)
1346 		qp_count = max_num_clients;
1347 	else if (nt->mw_count < qp_count)
1348 		qp_count = nt->mw_count;
1349 
1350 	qp_bitmap &= BIT_ULL(qp_count) - 1;
1351 
1352 	nt->qp_count = qp_count;
1353 	nt->qp_bitmap = qp_bitmap;
1354 	nt->qp_bitmap_free = qp_bitmap;
1355 
1356 	nt->qp_vec = kcalloc_node(qp_count, sizeof(*nt->qp_vec),
1357 				  GFP_KERNEL, node);
1358 	if (!nt->qp_vec) {
1359 		rc = -ENOMEM;
1360 		goto err1;
1361 	}
1362 
1363 	if (nt_debugfs_dir) {
1364 		nt->debugfs_node_dir =
1365 			debugfs_create_dir(pci_name(ndev->pdev),
1366 					   nt_debugfs_dir);
1367 	}
1368 
1369 	for (i = 0; i < qp_count; i++) {
1370 		rc = ntb_transport_init_queue(nt, i);
1371 		if (rc)
1372 			goto err2;
1373 	}
1374 
1375 	INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1376 	INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1377 
1378 	rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1379 	if (rc)
1380 		goto err2;
1381 
1382 	INIT_LIST_HEAD(&nt->client_devs);
1383 	rc = ntb_bus_init(nt);
1384 	if (rc)
1385 		goto err3;
1386 
1387 	nt->link_is_up = false;
1388 	ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1389 	ntb_link_event(ndev);
1390 
1391 	return 0;
1392 
1393 err3:
1394 	ntb_clear_ctx(ndev);
1395 err2:
1396 	kfree(nt->qp_vec);
1397 err1:
1398 	while (i--) {
1399 		mw = &nt->mw_vec[i];
1400 		iounmap(mw->vbase);
1401 	}
1402 	kfree(nt->mw_vec);
1403 err:
1404 	kfree(nt);
1405 	return rc;
1406 }
1407 
1408 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1409 {
1410 	struct ntb_transport_ctx *nt = ndev->ctx;
1411 	struct ntb_transport_qp *qp;
1412 	u64 qp_bitmap_alloc;
1413 	int i;
1414 
1415 	ntb_transport_link_cleanup(nt);
1416 	cancel_work_sync(&nt->link_cleanup);
1417 	cancel_delayed_work_sync(&nt->link_work);
1418 
1419 	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1420 
1421 	/* verify that all the qp's are freed */
1422 	for (i = 0; i < nt->qp_count; i++) {
1423 		qp = &nt->qp_vec[i];
1424 		if (qp_bitmap_alloc & BIT_ULL(i))
1425 			ntb_transport_free_queue(qp);
1426 		debugfs_remove_recursive(qp->debugfs_dir);
1427 	}
1428 
1429 	ntb_link_disable(ndev);
1430 	ntb_clear_ctx(ndev);
1431 
1432 	ntb_bus_remove(nt);
1433 
1434 	for (i = nt->mw_count; i--; ) {
1435 		ntb_free_mw(nt, i);
1436 		iounmap(nt->mw_vec[i].vbase);
1437 	}
1438 
1439 	kfree(nt->qp_vec);
1440 	kfree(nt->mw_vec);
1441 	kfree(nt);
1442 }
1443 
1444 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1445 {
1446 	struct ntb_queue_entry *entry;
1447 	void *cb_data;
1448 	unsigned int len;
1449 	unsigned long irqflags;
1450 
1451 	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1452 
1453 	while (!list_empty(&qp->rx_post_q)) {
1454 		entry = list_first_entry(&qp->rx_post_q,
1455 					 struct ntb_queue_entry, entry);
1456 		if (!(entry->flags & DESC_DONE_FLAG))
1457 			break;
1458 
1459 		entry->rx_hdr->flags = 0;
1460 		iowrite32(entry->rx_index, &qp->rx_info->entry);
1461 
1462 		cb_data = entry->cb_data;
1463 		len = entry->len;
1464 
1465 		list_move_tail(&entry->entry, &qp->rx_free_q);
1466 
1467 		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1468 
1469 		if (qp->rx_handler && qp->client_ready)
1470 			qp->rx_handler(qp, qp->cb_data, cb_data, len);
1471 
1472 		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1473 	}
1474 
1475 	spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1476 }
1477 
1478 static void ntb_rx_copy_callback(void *data,
1479 				 const struct dmaengine_result *res)
1480 {
1481 	struct ntb_queue_entry *entry = data;
1482 
1483 	/* we need to check DMA results if we are using DMA */
1484 	if (res) {
1485 		enum dmaengine_tx_result dma_err = res->result;
1486 
1487 		switch (dma_err) {
1488 		case DMA_TRANS_READ_FAILED:
1489 		case DMA_TRANS_WRITE_FAILED:
1490 			entry->errors++;
1491 			fallthrough;
1492 		case DMA_TRANS_ABORTED:
1493 		{
1494 			struct ntb_transport_qp *qp = entry->qp;
1495 			void *offset = qp->rx_buff + qp->rx_max_frame *
1496 					qp->rx_index;
1497 
1498 			ntb_memcpy_rx(entry, offset);
1499 			qp->rx_memcpy++;
1500 			return;
1501 		}
1502 
1503 		case DMA_TRANS_NOERROR:
1504 		default:
1505 			break;
1506 		}
1507 	}
1508 
1509 	entry->flags |= DESC_DONE_FLAG;
1510 
1511 	ntb_complete_rxc(entry->qp);
1512 }
1513 
1514 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1515 {
1516 	void *buf = entry->buf;
1517 	size_t len = entry->len;
1518 
1519 	memcpy(buf, offset, len);
1520 
1521 	/* Ensure that the data is fully copied out before clearing the flag */
1522 	wmb();
1523 
1524 	ntb_rx_copy_callback(entry, NULL);
1525 }
1526 
1527 static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset)
1528 {
1529 	struct dma_async_tx_descriptor *txd;
1530 	struct ntb_transport_qp *qp = entry->qp;
1531 	struct dma_chan *chan = qp->rx_dma_chan;
1532 	struct dma_device *device;
1533 	size_t pay_off, buff_off, len;
1534 	struct dmaengine_unmap_data *unmap;
1535 	dma_cookie_t cookie;
1536 	void *buf = entry->buf;
1537 
1538 	len = entry->len;
1539 	device = chan->device;
1540 	pay_off = (size_t)offset & ~PAGE_MASK;
1541 	buff_off = (size_t)buf & ~PAGE_MASK;
1542 
1543 	if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1544 		goto err;
1545 
1546 	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1547 	if (!unmap)
1548 		goto err;
1549 
1550 	unmap->len = len;
1551 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1552 				      pay_off, len, DMA_TO_DEVICE);
1553 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1554 		goto err_get_unmap;
1555 
1556 	unmap->to_cnt = 1;
1557 
1558 	unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1559 				      buff_off, len, DMA_FROM_DEVICE);
1560 	if (dma_mapping_error(device->dev, unmap->addr[1]))
1561 		goto err_get_unmap;
1562 
1563 	unmap->from_cnt = 1;
1564 
1565 	txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1566 					     unmap->addr[0], len,
1567 					     DMA_PREP_INTERRUPT);
1568 	if (!txd)
1569 		goto err_get_unmap;
1570 
1571 	txd->callback_result = ntb_rx_copy_callback;
1572 	txd->callback_param = entry;
1573 	dma_set_unmap(txd, unmap);
1574 
1575 	cookie = dmaengine_submit(txd);
1576 	if (dma_submit_error(cookie))
1577 		goto err_set_unmap;
1578 
1579 	dmaengine_unmap_put(unmap);
1580 
1581 	qp->last_cookie = cookie;
1582 
1583 	qp->rx_async++;
1584 
1585 	return 0;
1586 
1587 err_set_unmap:
1588 	dmaengine_unmap_put(unmap);
1589 err_get_unmap:
1590 	dmaengine_unmap_put(unmap);
1591 err:
1592 	return -ENXIO;
1593 }
1594 
1595 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1596 {
1597 	struct ntb_transport_qp *qp = entry->qp;
1598 	struct dma_chan *chan = qp->rx_dma_chan;
1599 	int res;
1600 
1601 	if (!chan)
1602 		goto err;
1603 
1604 	if (entry->len < copy_bytes)
1605 		goto err;
1606 
1607 	res = ntb_async_rx_submit(entry, offset);
1608 	if (res < 0)
1609 		goto err;
1610 
1611 	if (!entry->retries)
1612 		qp->rx_async++;
1613 
1614 	return;
1615 
1616 err:
1617 	ntb_memcpy_rx(entry, offset);
1618 	qp->rx_memcpy++;
1619 }
1620 
1621 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1622 {
1623 	struct ntb_payload_header *hdr;
1624 	struct ntb_queue_entry *entry;
1625 	void *offset;
1626 
1627 	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1628 	hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1629 
1630 	dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1631 		qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1632 
1633 	if (!(hdr->flags & DESC_DONE_FLAG)) {
1634 		dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1635 		qp->rx_ring_empty++;
1636 		return -EAGAIN;
1637 	}
1638 
1639 	if (hdr->flags & LINK_DOWN_FLAG) {
1640 		dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1641 		ntb_qp_link_down(qp);
1642 		hdr->flags = 0;
1643 		return -EAGAIN;
1644 	}
1645 
1646 	if (hdr->ver != (u32)qp->rx_pkts) {
1647 		dev_dbg(&qp->ndev->pdev->dev,
1648 			"version mismatch, expected %llu - got %u\n",
1649 			qp->rx_pkts, hdr->ver);
1650 		qp->rx_err_ver++;
1651 		return -EIO;
1652 	}
1653 
1654 	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1655 	if (!entry) {
1656 		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1657 		qp->rx_err_no_buf++;
1658 		return -EAGAIN;
1659 	}
1660 
1661 	entry->rx_hdr = hdr;
1662 	entry->rx_index = qp->rx_index;
1663 
1664 	if (hdr->len > entry->len) {
1665 		dev_dbg(&qp->ndev->pdev->dev,
1666 			"receive buffer overflow! Wanted %d got %d\n",
1667 			hdr->len, entry->len);
1668 		qp->rx_err_oflow++;
1669 
1670 		entry->len = -EIO;
1671 		entry->flags |= DESC_DONE_FLAG;
1672 
1673 		ntb_complete_rxc(qp);
1674 	} else {
1675 		dev_dbg(&qp->ndev->pdev->dev,
1676 			"RX OK index %u ver %u size %d into buf size %d\n",
1677 			qp->rx_index, hdr->ver, hdr->len, entry->len);
1678 
1679 		qp->rx_bytes += hdr->len;
1680 		qp->rx_pkts++;
1681 
1682 		entry->len = hdr->len;
1683 
1684 		ntb_async_rx(entry, offset);
1685 	}
1686 
1687 	qp->rx_index++;
1688 	qp->rx_index %= qp->rx_max_entry;
1689 
1690 	return 0;
1691 }
1692 
1693 static void ntb_transport_rxc_db(unsigned long data)
1694 {
1695 	struct ntb_transport_qp *qp = (void *)data;
1696 	int rc, i;
1697 
1698 	dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1699 		__func__, qp->qp_num);
1700 
1701 	/* Limit the number of packets processed in a single interrupt to
1702 	 * provide fairness to others
1703 	 */
1704 	for (i = 0; i < qp->rx_max_entry; i++) {
1705 		rc = ntb_process_rxc(qp);
1706 		if (rc)
1707 			break;
1708 	}
1709 
1710 	if (i && qp->rx_dma_chan)
1711 		dma_async_issue_pending(qp->rx_dma_chan);
1712 
1713 	if (i == qp->rx_max_entry) {
1714 		/* there is more work to do */
1715 		if (qp->active)
1716 			tasklet_schedule(&qp->rxc_db_work);
1717 	} else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1718 		/* the doorbell bit is set: clear it */
1719 		ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1720 		/* ntb_db_read ensures ntb_db_clear write is committed */
1721 		ntb_db_read(qp->ndev);
1722 
1723 		/* an interrupt may have arrived between finishing
1724 		 * ntb_process_rxc and clearing the doorbell bit:
1725 		 * there might be some more work to do.
1726 		 */
1727 		if (qp->active)
1728 			tasklet_schedule(&qp->rxc_db_work);
1729 	}
1730 }
1731 
1732 static void ntb_tx_copy_callback(void *data,
1733 				 const struct dmaengine_result *res)
1734 {
1735 	struct ntb_queue_entry *entry = data;
1736 	struct ntb_transport_qp *qp = entry->qp;
1737 	struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1738 
1739 	/* we need to check DMA results if we are using DMA */
1740 	if (res) {
1741 		enum dmaengine_tx_result dma_err = res->result;
1742 
1743 		switch (dma_err) {
1744 		case DMA_TRANS_READ_FAILED:
1745 		case DMA_TRANS_WRITE_FAILED:
1746 			entry->errors++;
1747 			fallthrough;
1748 		case DMA_TRANS_ABORTED:
1749 		{
1750 			void __iomem *offset =
1751 				qp->tx_mw + qp->tx_max_frame *
1752 				entry->tx_index;
1753 
1754 			/* resubmit via CPU */
1755 			ntb_memcpy_tx(entry, offset);
1756 			qp->tx_memcpy++;
1757 			return;
1758 		}
1759 
1760 		case DMA_TRANS_NOERROR:
1761 		default:
1762 			break;
1763 		}
1764 	}
1765 
1766 	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1767 
1768 	if (qp->use_msi)
1769 		ntb_msi_peer_trigger(qp->ndev, PIDX, &qp->peer_msi_desc);
1770 	else
1771 		ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1772 
1773 	/* The entry length can only be zero if the packet is intended to be a
1774 	 * "link down" or similar.  Since no payload is being sent in these
1775 	 * cases, there is nothing to add to the completion queue.
1776 	 */
1777 	if (entry->len > 0) {
1778 		qp->tx_bytes += entry->len;
1779 
1780 		if (qp->tx_handler)
1781 			qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1782 				       entry->len);
1783 	}
1784 
1785 	ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1786 }
1787 
1788 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1789 {
1790 #ifdef ARCH_HAS_NOCACHE_UACCESS
1791 	/*
1792 	 * Using non-temporal mov to improve performance on non-cached
1793 	 * writes, even though we aren't actually copying from user space.
1794 	 */
1795 	__copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1796 #else
1797 	memcpy_toio(offset, entry->buf, entry->len);
1798 #endif
1799 
1800 	/* Ensure that the data is fully copied out before setting the flags */
1801 	wmb();
1802 
1803 	ntb_tx_copy_callback(entry, NULL);
1804 }
1805 
1806 static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
1807 			       struct ntb_queue_entry *entry)
1808 {
1809 	struct dma_async_tx_descriptor *txd;
1810 	struct dma_chan *chan = qp->tx_dma_chan;
1811 	struct dma_device *device;
1812 	size_t len = entry->len;
1813 	void *buf = entry->buf;
1814 	size_t dest_off, buff_off;
1815 	struct dmaengine_unmap_data *unmap;
1816 	dma_addr_t dest;
1817 	dma_cookie_t cookie;
1818 
1819 	device = chan->device;
1820 	dest = qp->tx_mw_dma_addr + qp->tx_max_frame * entry->tx_index;
1821 	buff_off = (size_t)buf & ~PAGE_MASK;
1822 	dest_off = (size_t)dest & ~PAGE_MASK;
1823 
1824 	if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1825 		goto err;
1826 
1827 	unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1828 	if (!unmap)
1829 		goto err;
1830 
1831 	unmap->len = len;
1832 	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1833 				      buff_off, len, DMA_TO_DEVICE);
1834 	if (dma_mapping_error(device->dev, unmap->addr[0]))
1835 		goto err_get_unmap;
1836 
1837 	unmap->to_cnt = 1;
1838 
1839 	txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1840 					     DMA_PREP_INTERRUPT);
1841 	if (!txd)
1842 		goto err_get_unmap;
1843 
1844 	txd->callback_result = ntb_tx_copy_callback;
1845 	txd->callback_param = entry;
1846 	dma_set_unmap(txd, unmap);
1847 
1848 	cookie = dmaengine_submit(txd);
1849 	if (dma_submit_error(cookie))
1850 		goto err_set_unmap;
1851 
1852 	dmaengine_unmap_put(unmap);
1853 
1854 	dma_async_issue_pending(chan);
1855 
1856 	return 0;
1857 err_set_unmap:
1858 	dmaengine_unmap_put(unmap);
1859 err_get_unmap:
1860 	dmaengine_unmap_put(unmap);
1861 err:
1862 	return -ENXIO;
1863 }
1864 
1865 static void ntb_async_tx(struct ntb_transport_qp *qp,
1866 			 struct ntb_queue_entry *entry)
1867 {
1868 	struct ntb_payload_header __iomem *hdr;
1869 	struct dma_chan *chan = qp->tx_dma_chan;
1870 	void __iomem *offset;
1871 	int res;
1872 
1873 	entry->tx_index = qp->tx_index;
1874 	offset = qp->tx_mw + qp->tx_max_frame * entry->tx_index;
1875 	hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1876 	entry->tx_hdr = hdr;
1877 
1878 	iowrite32(entry->len, &hdr->len);
1879 	iowrite32((u32)qp->tx_pkts, &hdr->ver);
1880 
1881 	if (!chan)
1882 		goto err;
1883 
1884 	if (entry->len < copy_bytes)
1885 		goto err;
1886 
1887 	res = ntb_async_tx_submit(qp, entry);
1888 	if (res < 0)
1889 		goto err;
1890 
1891 	if (!entry->retries)
1892 		qp->tx_async++;
1893 
1894 	return;
1895 
1896 err:
1897 	ntb_memcpy_tx(entry, offset);
1898 	qp->tx_memcpy++;
1899 }
1900 
1901 static int ntb_process_tx(struct ntb_transport_qp *qp,
1902 			  struct ntb_queue_entry *entry)
1903 {
1904 	if (!ntb_transport_tx_free_entry(qp)) {
1905 		qp->tx_ring_full++;
1906 		return -EAGAIN;
1907 	}
1908 
1909 	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1910 		if (qp->tx_handler)
1911 			qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
1912 
1913 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1914 			     &qp->tx_free_q);
1915 		return 0;
1916 	}
1917 
1918 	ntb_async_tx(qp, entry);
1919 
1920 	qp->tx_index++;
1921 	qp->tx_index %= qp->tx_max_entry;
1922 
1923 	qp->tx_pkts++;
1924 
1925 	return 0;
1926 }
1927 
1928 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1929 {
1930 	struct pci_dev *pdev = qp->ndev->pdev;
1931 	struct ntb_queue_entry *entry;
1932 	int i, rc;
1933 
1934 	if (!qp->link_is_up)
1935 		return;
1936 
1937 	dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1938 
1939 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1940 		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1941 		if (entry)
1942 			break;
1943 		msleep(100);
1944 	}
1945 
1946 	if (!entry)
1947 		return;
1948 
1949 	entry->cb_data = NULL;
1950 	entry->buf = NULL;
1951 	entry->len = 0;
1952 	entry->flags = LINK_DOWN_FLAG;
1953 
1954 	rc = ntb_process_tx(qp, entry);
1955 	if (rc)
1956 		dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1957 			qp->qp_num);
1958 
1959 	ntb_qp_link_down_reset(qp);
1960 }
1961 
1962 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1963 {
1964 	return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1965 }
1966 
1967 /**
1968  * ntb_transport_create_queue - Create a new NTB transport layer queue
1969  * @rx_handler: receive callback function
1970  * @tx_handler: transmit callback function
1971  * @event_handler: event callback function
1972  *
1973  * Create a new NTB transport layer queue and provide the queue with a callback
1974  * routine for both transmit and receive.  The receive callback routine will be
1975  * used to pass up data when the transport has received it on the queue.   The
1976  * transmit callback routine will be called when the transport has completed the
1977  * transmission of the data on the queue and the data is ready to be freed.
1978  *
1979  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1980  */
1981 struct ntb_transport_qp *
1982 ntb_transport_create_queue(void *data, struct device *client_dev,
1983 			   const struct ntb_queue_handlers *handlers)
1984 {
1985 	struct ntb_dev *ndev;
1986 	struct pci_dev *pdev;
1987 	struct ntb_transport_ctx *nt;
1988 	struct ntb_queue_entry *entry;
1989 	struct ntb_transport_qp *qp;
1990 	u64 qp_bit;
1991 	unsigned int free_queue;
1992 	dma_cap_mask_t dma_mask;
1993 	int node;
1994 	int i;
1995 
1996 	ndev = dev_ntb(client_dev->parent);
1997 	pdev = ndev->pdev;
1998 	nt = ndev->ctx;
1999 
2000 	node = dev_to_node(&ndev->dev);
2001 
2002 	free_queue = ffs(nt->qp_bitmap_free);
2003 	if (!free_queue)
2004 		goto err;
2005 
2006 	/* decrement free_queue to make it zero based */
2007 	free_queue--;
2008 
2009 	qp = &nt->qp_vec[free_queue];
2010 	qp_bit = BIT_ULL(qp->qp_num);
2011 
2012 	nt->qp_bitmap_free &= ~qp_bit;
2013 
2014 	qp->cb_data = data;
2015 	qp->rx_handler = handlers->rx_handler;
2016 	qp->tx_handler = handlers->tx_handler;
2017 	qp->event_handler = handlers->event_handler;
2018 
2019 	dma_cap_zero(dma_mask);
2020 	dma_cap_set(DMA_MEMCPY, dma_mask);
2021 
2022 	if (use_dma) {
2023 		qp->tx_dma_chan =
2024 			dma_request_channel(dma_mask, ntb_dma_filter_fn,
2025 					    (void *)(unsigned long)node);
2026 		if (!qp->tx_dma_chan)
2027 			dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
2028 
2029 		qp->rx_dma_chan =
2030 			dma_request_channel(dma_mask, ntb_dma_filter_fn,
2031 					    (void *)(unsigned long)node);
2032 		if (!qp->rx_dma_chan)
2033 			dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
2034 	} else {
2035 		qp->tx_dma_chan = NULL;
2036 		qp->rx_dma_chan = NULL;
2037 	}
2038 
2039 	qp->tx_mw_dma_addr = 0;
2040 	if (qp->tx_dma_chan) {
2041 		qp->tx_mw_dma_addr =
2042 			dma_map_resource(qp->tx_dma_chan->device->dev,
2043 					 qp->tx_mw_phys, qp->tx_mw_size,
2044 					 DMA_FROM_DEVICE, 0);
2045 		if (dma_mapping_error(qp->tx_dma_chan->device->dev,
2046 				      qp->tx_mw_dma_addr)) {
2047 			qp->tx_mw_dma_addr = 0;
2048 			goto err1;
2049 		}
2050 	}
2051 
2052 	dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
2053 		qp->tx_dma_chan ? "DMA" : "CPU");
2054 
2055 	dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
2056 		qp->rx_dma_chan ? "DMA" : "CPU");
2057 
2058 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
2059 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
2060 		if (!entry)
2061 			goto err1;
2062 
2063 		entry->qp = qp;
2064 		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
2065 			     &qp->rx_free_q);
2066 	}
2067 	qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;
2068 
2069 	for (i = 0; i < qp->tx_max_entry; i++) {
2070 		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
2071 		if (!entry)
2072 			goto err2;
2073 
2074 		entry->qp = qp;
2075 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
2076 			     &qp->tx_free_q);
2077 	}
2078 
2079 	ntb_db_clear(qp->ndev, qp_bit);
2080 	ntb_db_clear_mask(qp->ndev, qp_bit);
2081 
2082 	dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
2083 
2084 	return qp;
2085 
2086 err2:
2087 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
2088 		kfree(entry);
2089 err1:
2090 	qp->rx_alloc_entry = 0;
2091 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
2092 		kfree(entry);
2093 	if (qp->tx_mw_dma_addr)
2094 		dma_unmap_resource(qp->tx_dma_chan->device->dev,
2095 				   qp->tx_mw_dma_addr, qp->tx_mw_size,
2096 				   DMA_FROM_DEVICE, 0);
2097 	if (qp->tx_dma_chan)
2098 		dma_release_channel(qp->tx_dma_chan);
2099 	if (qp->rx_dma_chan)
2100 		dma_release_channel(qp->rx_dma_chan);
2101 	nt->qp_bitmap_free |= qp_bit;
2102 err:
2103 	return NULL;
2104 }
2105 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
2106 
2107 /**
2108  * ntb_transport_free_queue - Frees NTB transport queue
2109  * @qp: NTB queue to be freed
2110  *
2111  * Frees NTB transport queue
2112  */
2113 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
2114 {
2115 	struct pci_dev *pdev;
2116 	struct ntb_queue_entry *entry;
2117 	u64 qp_bit;
2118 
2119 	if (!qp)
2120 		return;
2121 
2122 	pdev = qp->ndev->pdev;
2123 
2124 	qp->active = false;
2125 
2126 	if (qp->tx_dma_chan) {
2127 		struct dma_chan *chan = qp->tx_dma_chan;
2128 		/* Putting the dma_chan to NULL will force any new traffic to be
2129 		 * processed by the CPU instead of the DAM engine
2130 		 */
2131 		qp->tx_dma_chan = NULL;
2132 
2133 		/* Try to be nice and wait for any queued DMA engine
2134 		 * transactions to process before smashing it with a rock
2135 		 */
2136 		dma_sync_wait(chan, qp->last_cookie);
2137 		dmaengine_terminate_all(chan);
2138 
2139 		dma_unmap_resource(chan->device->dev,
2140 				   qp->tx_mw_dma_addr, qp->tx_mw_size,
2141 				   DMA_FROM_DEVICE, 0);
2142 
2143 		dma_release_channel(chan);
2144 	}
2145 
2146 	if (qp->rx_dma_chan) {
2147 		struct dma_chan *chan = qp->rx_dma_chan;
2148 		/* Putting the dma_chan to NULL will force any new traffic to be
2149 		 * processed by the CPU instead of the DAM engine
2150 		 */
2151 		qp->rx_dma_chan = NULL;
2152 
2153 		/* Try to be nice and wait for any queued DMA engine
2154 		 * transactions to process before smashing it with a rock
2155 		 */
2156 		dma_sync_wait(chan, qp->last_cookie);
2157 		dmaengine_terminate_all(chan);
2158 		dma_release_channel(chan);
2159 	}
2160 
2161 	qp_bit = BIT_ULL(qp->qp_num);
2162 
2163 	ntb_db_set_mask(qp->ndev, qp_bit);
2164 	tasklet_kill(&qp->rxc_db_work);
2165 
2166 	cancel_delayed_work_sync(&qp->link_work);
2167 
2168 	qp->cb_data = NULL;
2169 	qp->rx_handler = NULL;
2170 	qp->tx_handler = NULL;
2171 	qp->event_handler = NULL;
2172 
2173 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
2174 		kfree(entry);
2175 
2176 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
2177 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
2178 		kfree(entry);
2179 	}
2180 
2181 	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
2182 		dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
2183 		kfree(entry);
2184 	}
2185 
2186 	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
2187 		kfree(entry);
2188 
2189 	qp->transport->qp_bitmap_free |= qp_bit;
2190 
2191 	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
2192 }
2193 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
2194 
2195 /**
2196  * ntb_transport_rx_remove - Dequeues enqueued rx packet
2197  * @qp: NTB queue to be freed
2198  * @len: pointer to variable to write enqueued buffers length
2199  *
2200  * Dequeues unused buffers from receive queue.  Should only be used during
2201  * shutdown of qp.
2202  *
2203  * RETURNS: NULL error value on error, or void* for success.
2204  */
2205 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
2206 {
2207 	struct ntb_queue_entry *entry;
2208 	void *buf;
2209 
2210 	if (!qp || qp->client_ready)
2211 		return NULL;
2212 
2213 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
2214 	if (!entry)
2215 		return NULL;
2216 
2217 	buf = entry->cb_data;
2218 	*len = entry->len;
2219 
2220 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
2221 
2222 	return buf;
2223 }
2224 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
2225 
2226 /**
2227  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
2228  * @qp: NTB transport layer queue the entry is to be enqueued on
2229  * @cb: per buffer pointer for callback function to use
2230  * @data: pointer to data buffer that incoming packets will be copied into
2231  * @len: length of the data buffer
2232  *
2233  * Enqueue a new receive buffer onto the transport queue into which a NTB
2234  * payload can be received into.
2235  *
2236  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
2237  */
2238 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
2239 			     unsigned int len)
2240 {
2241 	struct ntb_queue_entry *entry;
2242 
2243 	if (!qp)
2244 		return -EINVAL;
2245 
2246 	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
2247 	if (!entry)
2248 		return -ENOMEM;
2249 
2250 	entry->cb_data = cb;
2251 	entry->buf = data;
2252 	entry->len = len;
2253 	entry->flags = 0;
2254 	entry->retries = 0;
2255 	entry->errors = 0;
2256 	entry->rx_index = 0;
2257 
2258 	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
2259 
2260 	if (qp->active)
2261 		tasklet_schedule(&qp->rxc_db_work);
2262 
2263 	return 0;
2264 }
2265 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
2266 
2267 /**
2268  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
2269  * @qp: NTB transport layer queue the entry is to be enqueued on
2270  * @cb: per buffer pointer for callback function to use
2271  * @data: pointer to data buffer that will be sent
2272  * @len: length of the data buffer
2273  *
2274  * Enqueue a new transmit buffer onto the transport queue from which a NTB
2275  * payload will be transmitted.  This assumes that a lock is being held to
2276  * serialize access to the qp.
2277  *
2278  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
2279  */
2280 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
2281 			     unsigned int len)
2282 {
2283 	struct ntb_queue_entry *entry;
2284 	int rc;
2285 
2286 	if (!qp || !len)
2287 		return -EINVAL;
2288 
2289 	/* If the qp link is down already, just ignore. */
2290 	if (!qp->link_is_up)
2291 		return 0;
2292 
2293 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
2294 	if (!entry) {
2295 		qp->tx_err_no_buf++;
2296 		return -EBUSY;
2297 	}
2298 
2299 	entry->cb_data = cb;
2300 	entry->buf = data;
2301 	entry->len = len;
2302 	entry->flags = 0;
2303 	entry->errors = 0;
2304 	entry->retries = 0;
2305 	entry->tx_index = 0;
2306 
2307 	rc = ntb_process_tx(qp, entry);
2308 	if (rc)
2309 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
2310 			     &qp->tx_free_q);
2311 
2312 	return rc;
2313 }
2314 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
2315 
2316 /**
2317  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
2318  * @qp: NTB transport layer queue to be enabled
2319  *
2320  * Notify NTB transport layer of client readiness to use queue
2321  */
2322 void ntb_transport_link_up(struct ntb_transport_qp *qp)
2323 {
2324 	if (!qp)
2325 		return;
2326 
2327 	qp->client_ready = true;
2328 
2329 	if (qp->transport->link_is_up)
2330 		schedule_delayed_work(&qp->link_work, 0);
2331 }
2332 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
2333 
2334 /**
2335  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
2336  * @qp: NTB transport layer queue to be disabled
2337  *
2338  * Notify NTB transport layer of client's desire to no longer receive data on
2339  * transport queue specified.  It is the client's responsibility to ensure all
2340  * entries on queue are purged or otherwise handled appropriately.
2341  */
2342 void ntb_transport_link_down(struct ntb_transport_qp *qp)
2343 {
2344 	int val;
2345 
2346 	if (!qp)
2347 		return;
2348 
2349 	qp->client_ready = false;
2350 
2351 	val = ntb_spad_read(qp->ndev, QP_LINKS);
2352 
2353 	ntb_peer_spad_write(qp->ndev, PIDX, QP_LINKS, val & ~BIT(qp->qp_num));
2354 
2355 	if (qp->link_is_up)
2356 		ntb_send_link_down(qp);
2357 	else
2358 		cancel_delayed_work_sync(&qp->link_work);
2359 }
2360 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
2361 
2362 /**
2363  * ntb_transport_link_query - Query transport link state
2364  * @qp: NTB transport layer queue to be queried
2365  *
2366  * Query connectivity to the remote system of the NTB transport queue
2367  *
2368  * RETURNS: true for link up or false for link down
2369  */
2370 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
2371 {
2372 	if (!qp)
2373 		return false;
2374 
2375 	return qp->link_is_up;
2376 }
2377 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
2378 
2379 /**
2380  * ntb_transport_qp_num - Query the qp number
2381  * @qp: NTB transport layer queue to be queried
2382  *
2383  * Query qp number of the NTB transport queue
2384  *
2385  * RETURNS: a zero based number specifying the qp number
2386  */
2387 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
2388 {
2389 	if (!qp)
2390 		return 0;
2391 
2392 	return qp->qp_num;
2393 }
2394 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
2395 
2396 /**
2397  * ntb_transport_max_size - Query the max payload size of a qp
2398  * @qp: NTB transport layer queue to be queried
2399  *
2400  * Query the maximum payload size permissible on the given qp
2401  *
2402  * RETURNS: the max payload size of a qp
2403  */
2404 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
2405 {
2406 	unsigned int max_size;
2407 	unsigned int copy_align;
2408 	struct dma_chan *rx_chan, *tx_chan;
2409 
2410 	if (!qp)
2411 		return 0;
2412 
2413 	rx_chan = qp->rx_dma_chan;
2414 	tx_chan = qp->tx_dma_chan;
2415 
2416 	copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
2417 			 tx_chan ? tx_chan->device->copy_align : 0);
2418 
2419 	/* If DMA engine usage is possible, try to find the max size for that */
2420 	max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
2421 	max_size = round_down(max_size, 1 << copy_align);
2422 
2423 	return max_size;
2424 }
2425 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
2426 
2427 unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
2428 {
2429 	unsigned int head = qp->tx_index;
2430 	unsigned int tail = qp->remote_rx_info->entry;
2431 
2432 	return tail >= head ? tail - head : qp->tx_max_entry + tail - head;
2433 }
2434 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
2435 
2436 static void ntb_transport_doorbell_callback(void *data, int vector)
2437 {
2438 	struct ntb_transport_ctx *nt = data;
2439 	struct ntb_transport_qp *qp;
2440 	u64 db_bits;
2441 	unsigned int qp_num;
2442 
2443 	if (ntb_db_read(nt->ndev) & nt->msi_db_mask) {
2444 		ntb_transport_msi_peer_desc_changed(nt);
2445 		ntb_db_clear(nt->ndev, nt->msi_db_mask);
2446 	}
2447 
2448 	db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
2449 		   ntb_db_vector_mask(nt->ndev, vector));
2450 
2451 	while (db_bits) {
2452 		qp_num = __ffs(db_bits);
2453 		qp = &nt->qp_vec[qp_num];
2454 
2455 		if (qp->active)
2456 			tasklet_schedule(&qp->rxc_db_work);
2457 
2458 		db_bits &= ~BIT_ULL(qp_num);
2459 	}
2460 }
2461 
2462 static const struct ntb_ctx_ops ntb_transport_ops = {
2463 	.link_event = ntb_transport_event_callback,
2464 	.db_event = ntb_transport_doorbell_callback,
2465 };
2466 
2467 static struct ntb_client ntb_transport_client = {
2468 	.ops = {
2469 		.probe = ntb_transport_probe,
2470 		.remove = ntb_transport_free,
2471 	},
2472 };
2473 
2474 static int __init ntb_transport_init(void)
2475 {
2476 	int rc;
2477 
2478 	pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2479 
2480 	if (debugfs_initialized())
2481 		nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2482 
2483 	rc = bus_register(&ntb_transport_bus);
2484 	if (rc)
2485 		goto err_bus;
2486 
2487 	rc = ntb_register_client(&ntb_transport_client);
2488 	if (rc)
2489 		goto err_client;
2490 
2491 	return 0;
2492 
2493 err_client:
2494 	bus_unregister(&ntb_transport_bus);
2495 err_bus:
2496 	debugfs_remove_recursive(nt_debugfs_dir);
2497 	return rc;
2498 }
2499 module_init(ntb_transport_init);
2500 
2501 static void __exit ntb_transport_exit(void)
2502 {
2503 	ntb_unregister_client(&ntb_transport_client);
2504 	bus_unregister(&ntb_transport_bus);
2505 	debugfs_remove_recursive(nt_debugfs_dir);
2506 }
2507 module_exit(ntb_transport_exit);
2508