Merge tag 'ntb-4.8' of git://github.com/jonmason/ntb
[sfrench/cifs-2.6.git] / drivers / ntb / ntb_transport.c
1 /*
2  * This file is provided under a dual BSD/GPLv2 license.  When using or
3  *   redistributing this file, you may do so under either license.
4  *
5  *   GPL LICENSE SUMMARY
6  *
7  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
8  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
9  *
10  *   This program is free software; you can redistribute it and/or modify
11  *   it under the terms of version 2 of the GNU General Public License as
12  *   published by the Free Software Foundation.
13  *
14  *   BSD LICENSE
15  *
16  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
17  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
18  *
19  *   Redistribution and use in source and binary forms, with or without
20  *   modification, are permitted provided that the following conditions
21  *   are met:
22  *
23  *     * Redistributions of source code must retain the above copyright
24  *       notice, this list of conditions and the following disclaimer.
25  *     * Redistributions in binary form must reproduce the above copy
26  *       notice, this list of conditions and the following disclaimer in
27  *       the documentation and/or other materials provided with the
28  *       distribution.
29  *     * Neither the name of Intel Corporation nor the names of its
30  *       contributors may be used to endorse or promote products derived
31  *       from this software without specific prior written permission.
32  *
33  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
34  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
35  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
36  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
37  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
40  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
41  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
42  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
43  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44  *
45  * PCIe NTB Transport Linux driver
46  *
47  * Contact Information:
48  * Jon Mason <jon.mason@intel.com>
49  */
50 #include <linux/debugfs.h>
51 #include <linux/delay.h>
52 #include <linux/dmaengine.h>
53 #include <linux/dma-mapping.h>
54 #include <linux/errno.h>
55 #include <linux/export.h>
56 #include <linux/interrupt.h>
57 #include <linux/module.h>
58 #include <linux/pci.h>
59 #include <linux/slab.h>
60 #include <linux/types.h>
61 #include <linux/uaccess.h>
62 #include "linux/ntb.h"
63 #include "linux/ntb_transport.h"
64
65 #define NTB_TRANSPORT_VERSION   4
66 #define NTB_TRANSPORT_VER       "4"
67 #define NTB_TRANSPORT_NAME      "ntb_transport"
68 #define NTB_TRANSPORT_DESC      "Software Queue-Pair Transport over NTB"
69
70 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
71 MODULE_VERSION(NTB_TRANSPORT_VER);
72 MODULE_LICENSE("Dual BSD/GPL");
73 MODULE_AUTHOR("Intel Corporation");
74
75 static unsigned long max_mw_size;
76 module_param(max_mw_size, ulong, 0644);
77 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
78
79 static unsigned int transport_mtu = 0x10000;
80 module_param(transport_mtu, uint, 0644);
81 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
82
83 static unsigned char max_num_clients;
84 module_param(max_num_clients, byte, 0644);
85 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
86
87 static unsigned int copy_bytes = 1024;
88 module_param(copy_bytes, uint, 0644);
89 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
90
91 static bool use_dma;
92 module_param(use_dma, bool, 0644);
93 MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
94
95 static struct dentry *nt_debugfs_dir;
96
97 struct ntb_queue_entry {
98         /* ntb_queue list reference */
99         struct list_head entry;
100         /* pointers to data to be transferred */
101         void *cb_data;
102         void *buf;
103         unsigned int len;
104         unsigned int flags;
105
106         struct ntb_transport_qp *qp;
107         union {
108                 struct ntb_payload_header __iomem *tx_hdr;
109                 struct ntb_payload_header *rx_hdr;
110         };
111         unsigned int index;
112 };
113
114 struct ntb_rx_info {
115         unsigned int entry;
116 };
117
118 struct ntb_transport_qp {
119         struct ntb_transport_ctx *transport;
120         struct ntb_dev *ndev;
121         void *cb_data;
122         struct dma_chan *tx_dma_chan;
123         struct dma_chan *rx_dma_chan;
124
125         bool client_ready;
126         bool link_is_up;
127         bool active;
128
129         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
130         u64 qp_bit;
131
132         struct ntb_rx_info __iomem *rx_info;
133         struct ntb_rx_info *remote_rx_info;
134
135         void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
136                            void *data, int len);
137         struct list_head tx_free_q;
138         spinlock_t ntb_tx_free_q_lock;
139         void __iomem *tx_mw;
140         dma_addr_t tx_mw_phys;
141         unsigned int tx_index;
142         unsigned int tx_max_entry;
143         unsigned int tx_max_frame;
144
145         void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
146                            void *data, int len);
147         struct list_head rx_post_q;
148         struct list_head rx_pend_q;
149         struct list_head rx_free_q;
150         /* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
151         spinlock_t ntb_rx_q_lock;
152         void *rx_buff;
153         unsigned int rx_index;
154         unsigned int rx_max_entry;
155         unsigned int rx_max_frame;
156         unsigned int rx_alloc_entry;
157         dma_cookie_t last_cookie;
158         struct tasklet_struct rxc_db_work;
159
160         void (*event_handler)(void *data, int status);
161         struct delayed_work link_work;
162         struct work_struct link_cleanup;
163
164         struct dentry *debugfs_dir;
165         struct dentry *debugfs_stats;
166
167         /* Stats */
168         u64 rx_bytes;
169         u64 rx_pkts;
170         u64 rx_ring_empty;
171         u64 rx_err_no_buf;
172         u64 rx_err_oflow;
173         u64 rx_err_ver;
174         u64 rx_memcpy;
175         u64 rx_async;
176         u64 dma_rx_prep_err;
177         u64 tx_bytes;
178         u64 tx_pkts;
179         u64 tx_ring_full;
180         u64 tx_err_no_buf;
181         u64 tx_memcpy;
182         u64 tx_async;
183         u64 dma_tx_prep_err;
184 };
185
186 struct ntb_transport_mw {
187         phys_addr_t phys_addr;
188         resource_size_t phys_size;
189         resource_size_t xlat_align;
190         resource_size_t xlat_align_size;
191         void __iomem *vbase;
192         size_t xlat_size;
193         size_t buff_size;
194         void *virt_addr;
195         dma_addr_t dma_addr;
196 };
197
198 struct ntb_transport_client_dev {
199         struct list_head entry;
200         struct ntb_transport_ctx *nt;
201         struct device dev;
202 };
203
204 struct ntb_transport_ctx {
205         struct list_head entry;
206         struct list_head client_devs;
207
208         struct ntb_dev *ndev;
209
210         struct ntb_transport_mw *mw_vec;
211         struct ntb_transport_qp *qp_vec;
212         unsigned int mw_count;
213         unsigned int qp_count;
214         u64 qp_bitmap;
215         u64 qp_bitmap_free;
216
217         bool link_is_up;
218         struct delayed_work link_work;
219         struct work_struct link_cleanup;
220
221         struct dentry *debugfs_node_dir;
222 };
223
224 enum {
225         DESC_DONE_FLAG = BIT(0),
226         LINK_DOWN_FLAG = BIT(1),
227 };
228
229 struct ntb_payload_header {
230         unsigned int ver;
231         unsigned int len;
232         unsigned int flags;
233 };
234
235 enum {
236         VERSION = 0,
237         QP_LINKS,
238         NUM_QPS,
239         NUM_MWS,
240         MW0_SZ_HIGH,
241         MW0_SZ_LOW,
242         MW1_SZ_HIGH,
243         MW1_SZ_LOW,
244         MAX_SPAD,
245 };
246
247 #define dev_client_dev(__dev) \
248         container_of((__dev), struct ntb_transport_client_dev, dev)
249
250 #define drv_client(__drv) \
251         container_of((__drv), struct ntb_transport_client, driver)
252
253 #define QP_TO_MW(nt, qp)        ((qp) % nt->mw_count)
254 #define NTB_QP_DEF_NUM_ENTRIES  100
255 #define NTB_LINK_DOWN_TIMEOUT   10
256 #define DMA_RETRIES             20
257 #define DMA_OUT_RESOURCE_TO     50
258
259 static void ntb_transport_rxc_db(unsigned long data);
260 static const struct ntb_ctx_ops ntb_transport_ops;
261 static struct ntb_client ntb_transport_client;
262
263 static int ntb_transport_bus_match(struct device *dev,
264                                    struct device_driver *drv)
265 {
266         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
267 }
268
269 static int ntb_transport_bus_probe(struct device *dev)
270 {
271         const struct ntb_transport_client *client;
272         int rc = -EINVAL;
273
274         get_device(dev);
275
276         client = drv_client(dev->driver);
277         rc = client->probe(dev);
278         if (rc)
279                 put_device(dev);
280
281         return rc;
282 }
283
284 static int ntb_transport_bus_remove(struct device *dev)
285 {
286         const struct ntb_transport_client *client;
287
288         client = drv_client(dev->driver);
289         client->remove(dev);
290
291         put_device(dev);
292
293         return 0;
294 }
295
296 static struct bus_type ntb_transport_bus = {
297         .name = "ntb_transport",
298         .match = ntb_transport_bus_match,
299         .probe = ntb_transport_bus_probe,
300         .remove = ntb_transport_bus_remove,
301 };
302
303 static LIST_HEAD(ntb_transport_list);
304
305 static int ntb_bus_init(struct ntb_transport_ctx *nt)
306 {
307         list_add_tail(&nt->entry, &ntb_transport_list);
308         return 0;
309 }
310
311 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
312 {
313         struct ntb_transport_client_dev *client_dev, *cd;
314
315         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
316                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
317                         dev_name(&client_dev->dev));
318                 list_del(&client_dev->entry);
319                 device_unregister(&client_dev->dev);
320         }
321
322         list_del(&nt->entry);
323 }
324
325 static void ntb_transport_client_release(struct device *dev)
326 {
327         struct ntb_transport_client_dev *client_dev;
328
329         client_dev = dev_client_dev(dev);
330         kfree(client_dev);
331 }
332
333 /**
334  * ntb_transport_unregister_client_dev - Unregister NTB client device
335  * @device_name: Name of NTB client device
336  *
337  * Unregister an NTB client device with the NTB transport layer
338  */
339 void ntb_transport_unregister_client_dev(char *device_name)
340 {
341         struct ntb_transport_client_dev *client, *cd;
342         struct ntb_transport_ctx *nt;
343
344         list_for_each_entry(nt, &ntb_transport_list, entry)
345                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
346                         if (!strncmp(dev_name(&client->dev), device_name,
347                                      strlen(device_name))) {
348                                 list_del(&client->entry);
349                                 device_unregister(&client->dev);
350                         }
351 }
352 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
353
354 /**
355  * ntb_transport_register_client_dev - Register NTB client device
356  * @device_name: Name of NTB client device
357  *
358  * Register an NTB client device with the NTB transport layer
359  */
360 int ntb_transport_register_client_dev(char *device_name)
361 {
362         struct ntb_transport_client_dev *client_dev;
363         struct ntb_transport_ctx *nt;
364         int node;
365         int rc, i = 0;
366
367         if (list_empty(&ntb_transport_list))
368                 return -ENODEV;
369
370         list_for_each_entry(nt, &ntb_transport_list, entry) {
371                 struct device *dev;
372
373                 node = dev_to_node(&nt->ndev->dev);
374
375                 client_dev = kzalloc_node(sizeof(*client_dev),
376                                           GFP_KERNEL, node);
377                 if (!client_dev) {
378                         rc = -ENOMEM;
379                         goto err;
380                 }
381
382                 dev = &client_dev->dev;
383
384                 /* setup and register client devices */
385                 dev_set_name(dev, "%s%d", device_name, i);
386                 dev->bus = &ntb_transport_bus;
387                 dev->release = ntb_transport_client_release;
388                 dev->parent = &nt->ndev->dev;
389
390                 rc = device_register(dev);
391                 if (rc) {
392                         kfree(client_dev);
393                         goto err;
394                 }
395
396                 list_add_tail(&client_dev->entry, &nt->client_devs);
397                 i++;
398         }
399
400         return 0;
401
402 err:
403         ntb_transport_unregister_client_dev(device_name);
404
405         return rc;
406 }
407 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
408
409 /**
410  * ntb_transport_register_client - Register NTB client driver
411  * @drv: NTB client driver to be registered
412  *
413  * Register an NTB client driver with the NTB transport layer
414  *
415  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
416  */
417 int ntb_transport_register_client(struct ntb_transport_client *drv)
418 {
419         drv->driver.bus = &ntb_transport_bus;
420
421         if (list_empty(&ntb_transport_list))
422                 return -ENODEV;
423
424         return driver_register(&drv->driver);
425 }
426 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
427
428 /**
429  * ntb_transport_unregister_client - Unregister NTB client driver
430  * @drv: NTB client driver to be unregistered
431  *
432  * Unregister an NTB client driver with the NTB transport layer
433  *
434  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
435  */
436 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
437 {
438         driver_unregister(&drv->driver);
439 }
440 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
441
442 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
443                             loff_t *offp)
444 {
445         struct ntb_transport_qp *qp;
446         char *buf;
447         ssize_t ret, out_offset, out_count;
448
449         qp = filp->private_data;
450
451         if (!qp || !qp->link_is_up)
452                 return 0;
453
454         out_count = 1000;
455
456         buf = kmalloc(out_count, GFP_KERNEL);
457         if (!buf)
458                 return -ENOMEM;
459
460         out_offset = 0;
461         out_offset += snprintf(buf + out_offset, out_count - out_offset,
462                                "\nNTB QP stats:\n\n");
463         out_offset += snprintf(buf + out_offset, out_count - out_offset,
464                                "rx_bytes - \t%llu\n", qp->rx_bytes);
465         out_offset += snprintf(buf + out_offset, out_count - out_offset,
466                                "rx_pkts - \t%llu\n", qp->rx_pkts);
467         out_offset += snprintf(buf + out_offset, out_count - out_offset,
468                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
469         out_offset += snprintf(buf + out_offset, out_count - out_offset,
470                                "rx_async - \t%llu\n", qp->rx_async);
471         out_offset += snprintf(buf + out_offset, out_count - out_offset,
472                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
473         out_offset += snprintf(buf + out_offset, out_count - out_offset,
474                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
475         out_offset += snprintf(buf + out_offset, out_count - out_offset,
476                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
477         out_offset += snprintf(buf + out_offset, out_count - out_offset,
478                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
479         out_offset += snprintf(buf + out_offset, out_count - out_offset,
480                                "rx_buff - \t0x%p\n", qp->rx_buff);
481         out_offset += snprintf(buf + out_offset, out_count - out_offset,
482                                "rx_index - \t%u\n", qp->rx_index);
483         out_offset += snprintf(buf + out_offset, out_count - out_offset,
484                                "rx_max_entry - \t%u\n", qp->rx_max_entry);
485         out_offset += snprintf(buf + out_offset, out_count - out_offset,
486                                "rx_alloc_entry - \t%u\n\n", qp->rx_alloc_entry);
487
488         out_offset += snprintf(buf + out_offset, out_count - out_offset,
489                                "tx_bytes - \t%llu\n", qp->tx_bytes);
490         out_offset += snprintf(buf + out_offset, out_count - out_offset,
491                                "tx_pkts - \t%llu\n", qp->tx_pkts);
492         out_offset += snprintf(buf + out_offset, out_count - out_offset,
493                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
494         out_offset += snprintf(buf + out_offset, out_count - out_offset,
495                                "tx_async - \t%llu\n", qp->tx_async);
496         out_offset += snprintf(buf + out_offset, out_count - out_offset,
497                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
498         out_offset += snprintf(buf + out_offset, out_count - out_offset,
499                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
500         out_offset += snprintf(buf + out_offset, out_count - out_offset,
501                                "tx_mw - \t0x%p\n", qp->tx_mw);
502         out_offset += snprintf(buf + out_offset, out_count - out_offset,
503                                "tx_index (H) - \t%u\n", qp->tx_index);
504         out_offset += snprintf(buf + out_offset, out_count - out_offset,
505                                "RRI (T) - \t%u\n",
506                                qp->remote_rx_info->entry);
507         out_offset += snprintf(buf + out_offset, out_count - out_offset,
508                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
509         out_offset += snprintf(buf + out_offset, out_count - out_offset,
510                                "free tx - \t%u\n",
511                                ntb_transport_tx_free_entry(qp));
512         out_offset += snprintf(buf + out_offset, out_count - out_offset,
513                                "DMA tx prep err - \t%llu\n",
514                                qp->dma_tx_prep_err);
515         out_offset += snprintf(buf + out_offset, out_count - out_offset,
516                                "DMA rx prep err - \t%llu\n",
517                                qp->dma_rx_prep_err);
518
519         out_offset += snprintf(buf + out_offset, out_count - out_offset,
520                                "\n");
521         out_offset += snprintf(buf + out_offset, out_count - out_offset,
522                                "Using TX DMA - \t%s\n",
523                                qp->tx_dma_chan ? "Yes" : "No");
524         out_offset += snprintf(buf + out_offset, out_count - out_offset,
525                                "Using RX DMA - \t%s\n",
526                                qp->rx_dma_chan ? "Yes" : "No");
527         out_offset += snprintf(buf + out_offset, out_count - out_offset,
528                                "QP Link - \t%s\n",
529                                qp->link_is_up ? "Up" : "Down");
530         out_offset += snprintf(buf + out_offset, out_count - out_offset,
531                                "\n");
532
533         if (out_offset > out_count)
534                 out_offset = out_count;
535
536         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
537         kfree(buf);
538         return ret;
539 }
540
541 static const struct file_operations ntb_qp_debugfs_stats = {
542         .owner = THIS_MODULE,
543         .open = simple_open,
544         .read = debugfs_read,
545 };
546
547 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
548                          struct list_head *list)
549 {
550         unsigned long flags;
551
552         spin_lock_irqsave(lock, flags);
553         list_add_tail(entry, list);
554         spin_unlock_irqrestore(lock, flags);
555 }
556
557 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
558                                            struct list_head *list)
559 {
560         struct ntb_queue_entry *entry;
561         unsigned long flags;
562
563         spin_lock_irqsave(lock, flags);
564         if (list_empty(list)) {
565                 entry = NULL;
566                 goto out;
567         }
568         entry = list_first_entry(list, struct ntb_queue_entry, entry);
569         list_del(&entry->entry);
570
571 out:
572         spin_unlock_irqrestore(lock, flags);
573
574         return entry;
575 }
576
577 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
578                                            struct list_head *list,
579                                            struct list_head *to_list)
580 {
581         struct ntb_queue_entry *entry;
582         unsigned long flags;
583
584         spin_lock_irqsave(lock, flags);
585
586         if (list_empty(list)) {
587                 entry = NULL;
588         } else {
589                 entry = list_first_entry(list, struct ntb_queue_entry, entry);
590                 list_move_tail(&entry->entry, to_list);
591         }
592
593         spin_unlock_irqrestore(lock, flags);
594
595         return entry;
596 }
597
598 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
599                                      unsigned int qp_num)
600 {
601         struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
602         struct ntb_transport_mw *mw;
603         struct ntb_dev *ndev = nt->ndev;
604         struct ntb_queue_entry *entry;
605         unsigned int rx_size, num_qps_mw;
606         unsigned int mw_num, mw_count, qp_count;
607         unsigned int i;
608         int node;
609
610         mw_count = nt->mw_count;
611         qp_count = nt->qp_count;
612
613         mw_num = QP_TO_MW(nt, qp_num);
614         mw = &nt->mw_vec[mw_num];
615
616         if (!mw->virt_addr)
617                 return -ENOMEM;
618
619         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
620                 num_qps_mw = qp_count / mw_count + 1;
621         else
622                 num_qps_mw = qp_count / mw_count;
623
624         rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
625         qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
626         rx_size -= sizeof(struct ntb_rx_info);
627
628         qp->remote_rx_info = qp->rx_buff + rx_size;
629
630         /* Due to housekeeping, there must be atleast 2 buffs */
631         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
632         qp->rx_max_entry = rx_size / qp->rx_max_frame;
633         qp->rx_index = 0;
634
635         /*
636          * Checking to see if we have more entries than the default.
637          * We should add additional entries if that is the case so we
638          * can be in sync with the transport frames.
639          */
640         node = dev_to_node(&ndev->dev);
641         for (i = qp->rx_alloc_entry; i < qp->rx_max_entry; i++) {
642                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
643                 if (!entry)
644                         return -ENOMEM;
645
646                 entry->qp = qp;
647                 ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
648                              &qp->rx_free_q);
649                 qp->rx_alloc_entry++;
650         }
651
652         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
653
654         /* setup the hdr offsets with 0's */
655         for (i = 0; i < qp->rx_max_entry; i++) {
656                 void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
657                                 sizeof(struct ntb_payload_header));
658                 memset(offset, 0, sizeof(struct ntb_payload_header));
659         }
660
661         qp->rx_pkts = 0;
662         qp->tx_pkts = 0;
663         qp->tx_index = 0;
664
665         return 0;
666 }
667
668 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
669 {
670         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
671         struct pci_dev *pdev = nt->ndev->pdev;
672
673         if (!mw->virt_addr)
674                 return;
675
676         ntb_mw_clear_trans(nt->ndev, num_mw);
677         dma_free_coherent(&pdev->dev, mw->buff_size,
678                           mw->virt_addr, mw->dma_addr);
679         mw->xlat_size = 0;
680         mw->buff_size = 0;
681         mw->virt_addr = NULL;
682 }
683
684 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
685                       resource_size_t size)
686 {
687         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
688         struct pci_dev *pdev = nt->ndev->pdev;
689         size_t xlat_size, buff_size;
690         int rc;
691
692         if (!size)
693                 return -EINVAL;
694
695         xlat_size = round_up(size, mw->xlat_align_size);
696         buff_size = round_up(size, mw->xlat_align);
697
698         /* No need to re-setup */
699         if (mw->xlat_size == xlat_size)
700                 return 0;
701
702         if (mw->buff_size)
703                 ntb_free_mw(nt, num_mw);
704
705         /* Alloc memory for receiving data.  Must be aligned */
706         mw->xlat_size = xlat_size;
707         mw->buff_size = buff_size;
708
709         mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
710                                            &mw->dma_addr, GFP_KERNEL);
711         if (!mw->virt_addr) {
712                 mw->xlat_size = 0;
713                 mw->buff_size = 0;
714                 dev_err(&pdev->dev, "Unable to alloc MW buff of size %zu\n",
715                         buff_size);
716                 return -ENOMEM;
717         }
718
719         /*
720          * we must ensure that the memory address allocated is BAR size
721          * aligned in order for the XLAT register to take the value. This
722          * is a requirement of the hardware. It is recommended to setup CMA
723          * for BAR sizes equal or greater than 4MB.
724          */
725         if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
726                 dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
727                         &mw->dma_addr);
728                 ntb_free_mw(nt, num_mw);
729                 return -ENOMEM;
730         }
731
732         /* Notify HW the memory location of the receive buffer */
733         rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
734         if (rc) {
735                 dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
736                 ntb_free_mw(nt, num_mw);
737                 return -EIO;
738         }
739
740         return 0;
741 }
742
743 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
744 {
745         qp->link_is_up = false;
746         qp->active = false;
747
748         qp->tx_index = 0;
749         qp->rx_index = 0;
750         qp->rx_bytes = 0;
751         qp->rx_pkts = 0;
752         qp->rx_ring_empty = 0;
753         qp->rx_err_no_buf = 0;
754         qp->rx_err_oflow = 0;
755         qp->rx_err_ver = 0;
756         qp->rx_memcpy = 0;
757         qp->rx_async = 0;
758         qp->tx_bytes = 0;
759         qp->tx_pkts = 0;
760         qp->tx_ring_full = 0;
761         qp->tx_err_no_buf = 0;
762         qp->tx_memcpy = 0;
763         qp->tx_async = 0;
764         qp->dma_tx_prep_err = 0;
765         qp->dma_rx_prep_err = 0;
766 }
767
768 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
769 {
770         struct ntb_transport_ctx *nt = qp->transport;
771         struct pci_dev *pdev = nt->ndev->pdev;
772
773         dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
774
775         cancel_delayed_work_sync(&qp->link_work);
776         ntb_qp_link_down_reset(qp);
777
778         if (qp->event_handler)
779                 qp->event_handler(qp->cb_data, qp->link_is_up);
780 }
781
782 static void ntb_qp_link_cleanup_work(struct work_struct *work)
783 {
784         struct ntb_transport_qp *qp = container_of(work,
785                                                    struct ntb_transport_qp,
786                                                    link_cleanup);
787         struct ntb_transport_ctx *nt = qp->transport;
788
789         ntb_qp_link_cleanup(qp);
790
791         if (nt->link_is_up)
792                 schedule_delayed_work(&qp->link_work,
793                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
794 }
795
796 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
797 {
798         schedule_work(&qp->link_cleanup);
799 }
800
801 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
802 {
803         struct ntb_transport_qp *qp;
804         u64 qp_bitmap_alloc;
805         int i;
806
807         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
808
809         /* Pass along the info to any clients */
810         for (i = 0; i < nt->qp_count; i++)
811                 if (qp_bitmap_alloc & BIT_ULL(i)) {
812                         qp = &nt->qp_vec[i];
813                         ntb_qp_link_cleanup(qp);
814                         cancel_work_sync(&qp->link_cleanup);
815                         cancel_delayed_work_sync(&qp->link_work);
816                 }
817
818         if (!nt->link_is_up)
819                 cancel_delayed_work_sync(&nt->link_work);
820
821         /* The scratchpad registers keep the values if the remote side
822          * goes down, blast them now to give them a sane value the next
823          * time they are accessed
824          */
825         for (i = 0; i < MAX_SPAD; i++)
826                 ntb_spad_write(nt->ndev, i, 0);
827 }
828
829 static void ntb_transport_link_cleanup_work(struct work_struct *work)
830 {
831         struct ntb_transport_ctx *nt =
832                 container_of(work, struct ntb_transport_ctx, link_cleanup);
833
834         ntb_transport_link_cleanup(nt);
835 }
836
837 static void ntb_transport_event_callback(void *data)
838 {
839         struct ntb_transport_ctx *nt = data;
840
841         if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
842                 schedule_delayed_work(&nt->link_work, 0);
843         else
844                 schedule_work(&nt->link_cleanup);
845 }
846
847 static void ntb_transport_link_work(struct work_struct *work)
848 {
849         struct ntb_transport_ctx *nt =
850                 container_of(work, struct ntb_transport_ctx, link_work.work);
851         struct ntb_dev *ndev = nt->ndev;
852         struct pci_dev *pdev = ndev->pdev;
853         resource_size_t size;
854         u32 val;
855         int rc = 0, i, spad;
856
857         /* send the local info, in the opposite order of the way we read it */
858         for (i = 0; i < nt->mw_count; i++) {
859                 size = nt->mw_vec[i].phys_size;
860
861                 if (max_mw_size && size > max_mw_size)
862                         size = max_mw_size;
863
864                 spad = MW0_SZ_HIGH + (i * 2);
865                 ntb_peer_spad_write(ndev, spad, upper_32_bits(size));
866
867                 spad = MW0_SZ_LOW + (i * 2);
868                 ntb_peer_spad_write(ndev, spad, lower_32_bits(size));
869         }
870
871         ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
872
873         ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
874
875         ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
876
877         /* Query the remote side for its info */
878         val = ntb_spad_read(ndev, VERSION);
879         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
880         if (val != NTB_TRANSPORT_VERSION)
881                 goto out;
882
883         val = ntb_spad_read(ndev, NUM_QPS);
884         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
885         if (val != nt->qp_count)
886                 goto out;
887
888         val = ntb_spad_read(ndev, NUM_MWS);
889         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
890         if (val != nt->mw_count)
891                 goto out;
892
893         for (i = 0; i < nt->mw_count; i++) {
894                 u64 val64;
895
896                 val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
897                 val64 = (u64)val << 32;
898
899                 val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
900                 val64 |= val;
901
902                 dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
903
904                 rc = ntb_set_mw(nt, i, val64);
905                 if (rc)
906                         goto out1;
907         }
908
909         nt->link_is_up = true;
910
911         for (i = 0; i < nt->qp_count; i++) {
912                 struct ntb_transport_qp *qp = &nt->qp_vec[i];
913
914                 ntb_transport_setup_qp_mw(nt, i);
915
916                 if (qp->client_ready)
917                         schedule_delayed_work(&qp->link_work, 0);
918         }
919
920         return;
921
922 out1:
923         for (i = 0; i < nt->mw_count; i++)
924                 ntb_free_mw(nt, i);
925
926         /* if there's an actual failure, we should just bail */
927         if (rc < 0) {
928                 ntb_link_disable(ndev);
929                 return;
930         }
931
932 out:
933         if (ntb_link_is_up(ndev, NULL, NULL) == 1)
934                 schedule_delayed_work(&nt->link_work,
935                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
936 }
937
938 static void ntb_qp_link_work(struct work_struct *work)
939 {
940         struct ntb_transport_qp *qp = container_of(work,
941                                                    struct ntb_transport_qp,
942                                                    link_work.work);
943         struct pci_dev *pdev = qp->ndev->pdev;
944         struct ntb_transport_ctx *nt = qp->transport;
945         int val;
946
947         WARN_ON(!nt->link_is_up);
948
949         val = ntb_spad_read(nt->ndev, QP_LINKS);
950
951         ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
952
953         /* query remote spad for qp ready bits */
954         ntb_peer_spad_read(nt->ndev, QP_LINKS);
955         dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
956
957         /* See if the remote side is up */
958         if (val & BIT(qp->qp_num)) {
959                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
960                 qp->link_is_up = true;
961                 qp->active = true;
962
963                 if (qp->event_handler)
964                         qp->event_handler(qp->cb_data, qp->link_is_up);
965
966                 if (qp->active)
967                         tasklet_schedule(&qp->rxc_db_work);
968         } else if (nt->link_is_up)
969                 schedule_delayed_work(&qp->link_work,
970                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
971 }
972
973 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
974                                     unsigned int qp_num)
975 {
976         struct ntb_transport_qp *qp;
977         phys_addr_t mw_base;
978         resource_size_t mw_size;
979         unsigned int num_qps_mw, tx_size;
980         unsigned int mw_num, mw_count, qp_count;
981         u64 qp_offset;
982
983         mw_count = nt->mw_count;
984         qp_count = nt->qp_count;
985
986         mw_num = QP_TO_MW(nt, qp_num);
987
988         qp = &nt->qp_vec[qp_num];
989         qp->qp_num = qp_num;
990         qp->transport = nt;
991         qp->ndev = nt->ndev;
992         qp->client_ready = false;
993         qp->event_handler = NULL;
994         ntb_qp_link_down_reset(qp);
995
996         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
997                 num_qps_mw = qp_count / mw_count + 1;
998         else
999                 num_qps_mw = qp_count / mw_count;
1000
1001         mw_base = nt->mw_vec[mw_num].phys_addr;
1002         mw_size = nt->mw_vec[mw_num].phys_size;
1003
1004         tx_size = (unsigned int)mw_size / num_qps_mw;
1005         qp_offset = tx_size * (qp_num / mw_count);
1006
1007         qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
1008         if (!qp->tx_mw)
1009                 return -EINVAL;
1010
1011         qp->tx_mw_phys = mw_base + qp_offset;
1012         if (!qp->tx_mw_phys)
1013                 return -EINVAL;
1014
1015         tx_size -= sizeof(struct ntb_rx_info);
1016         qp->rx_info = qp->tx_mw + tx_size;
1017
1018         /* Due to housekeeping, there must be atleast 2 buffs */
1019         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
1020         qp->tx_max_entry = tx_size / qp->tx_max_frame;
1021
1022         if (nt->debugfs_node_dir) {
1023                 char debugfs_name[4];
1024
1025                 snprintf(debugfs_name, 4, "qp%d", qp_num);
1026                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
1027                                                      nt->debugfs_node_dir);
1028
1029                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
1030                                                         qp->debugfs_dir, qp,
1031                                                         &ntb_qp_debugfs_stats);
1032         } else {
1033                 qp->debugfs_dir = NULL;
1034                 qp->debugfs_stats = NULL;
1035         }
1036
1037         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
1038         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
1039
1040         spin_lock_init(&qp->ntb_rx_q_lock);
1041         spin_lock_init(&qp->ntb_tx_free_q_lock);
1042
1043         INIT_LIST_HEAD(&qp->rx_post_q);
1044         INIT_LIST_HEAD(&qp->rx_pend_q);
1045         INIT_LIST_HEAD(&qp->rx_free_q);
1046         INIT_LIST_HEAD(&qp->tx_free_q);
1047
1048         tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
1049                      (unsigned long)qp);
1050
1051         return 0;
1052 }
1053
1054 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
1055 {
1056         struct ntb_transport_ctx *nt;
1057         struct ntb_transport_mw *mw;
1058         unsigned int mw_count, qp_count;
1059         u64 qp_bitmap;
1060         int node;
1061         int rc, i;
1062
1063         mw_count = ntb_mw_count(ndev);
1064         if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count * 2)) {
1065                 dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
1066                         NTB_TRANSPORT_NAME);
1067                 return -EIO;
1068         }
1069
1070         if (ntb_db_is_unsafe(ndev))
1071                 dev_dbg(&ndev->dev,
1072                         "doorbell is unsafe, proceed anyway...\n");
1073         if (ntb_spad_is_unsafe(ndev))
1074                 dev_dbg(&ndev->dev,
1075                         "scratchpad is unsafe, proceed anyway...\n");
1076
1077         node = dev_to_node(&ndev->dev);
1078
1079         nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1080         if (!nt)
1081                 return -ENOMEM;
1082
1083         nt->ndev = ndev;
1084
1085         nt->mw_count = mw_count;
1086
1087         nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
1088                                   GFP_KERNEL, node);
1089         if (!nt->mw_vec) {
1090                 rc = -ENOMEM;
1091                 goto err;
1092         }
1093
1094         for (i = 0; i < mw_count; i++) {
1095                 mw = &nt->mw_vec[i];
1096
1097                 rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
1098                                       &mw->xlat_align, &mw->xlat_align_size);
1099                 if (rc)
1100                         goto err1;
1101
1102                 mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1103                 if (!mw->vbase) {
1104                         rc = -ENOMEM;
1105                         goto err1;
1106                 }
1107
1108                 mw->buff_size = 0;
1109                 mw->xlat_size = 0;
1110                 mw->virt_addr = NULL;
1111                 mw->dma_addr = 0;
1112         }
1113
1114         qp_bitmap = ntb_db_valid_mask(ndev);
1115
1116         qp_count = ilog2(qp_bitmap);
1117         if (max_num_clients && max_num_clients < qp_count)
1118                 qp_count = max_num_clients;
1119         else if (mw_count < qp_count)
1120                 qp_count = mw_count;
1121
1122         qp_bitmap &= BIT_ULL(qp_count) - 1;
1123
1124         nt->qp_count = qp_count;
1125         nt->qp_bitmap = qp_bitmap;
1126         nt->qp_bitmap_free = qp_bitmap;
1127
1128         nt->qp_vec = kzalloc_node(qp_count * sizeof(*nt->qp_vec),
1129                                   GFP_KERNEL, node);
1130         if (!nt->qp_vec) {
1131                 rc = -ENOMEM;
1132                 goto err1;
1133         }
1134
1135         if (nt_debugfs_dir) {
1136                 nt->debugfs_node_dir =
1137                         debugfs_create_dir(pci_name(ndev->pdev),
1138                                            nt_debugfs_dir);
1139         }
1140
1141         for (i = 0; i < qp_count; i++) {
1142                 rc = ntb_transport_init_queue(nt, i);
1143                 if (rc)
1144                         goto err2;
1145         }
1146
1147         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1148         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1149
1150         rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1151         if (rc)
1152                 goto err2;
1153
1154         INIT_LIST_HEAD(&nt->client_devs);
1155         rc = ntb_bus_init(nt);
1156         if (rc)
1157                 goto err3;
1158
1159         nt->link_is_up = false;
1160         ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1161         ntb_link_event(ndev);
1162
1163         return 0;
1164
1165 err3:
1166         ntb_clear_ctx(ndev);
1167 err2:
1168         kfree(nt->qp_vec);
1169 err1:
1170         while (i--) {
1171                 mw = &nt->mw_vec[i];
1172                 iounmap(mw->vbase);
1173         }
1174         kfree(nt->mw_vec);
1175 err:
1176         kfree(nt);
1177         return rc;
1178 }
1179
1180 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1181 {
1182         struct ntb_transport_ctx *nt = ndev->ctx;
1183         struct ntb_transport_qp *qp;
1184         u64 qp_bitmap_alloc;
1185         int i;
1186
1187         ntb_transport_link_cleanup(nt);
1188         cancel_work_sync(&nt->link_cleanup);
1189         cancel_delayed_work_sync(&nt->link_work);
1190
1191         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1192
1193         /* verify that all the qp's are freed */
1194         for (i = 0; i < nt->qp_count; i++) {
1195                 qp = &nt->qp_vec[i];
1196                 if (qp_bitmap_alloc & BIT_ULL(i))
1197                         ntb_transport_free_queue(qp);
1198                 debugfs_remove_recursive(qp->debugfs_dir);
1199         }
1200
1201         ntb_link_disable(ndev);
1202         ntb_clear_ctx(ndev);
1203
1204         ntb_bus_remove(nt);
1205
1206         for (i = nt->mw_count; i--; ) {
1207                 ntb_free_mw(nt, i);
1208                 iounmap(nt->mw_vec[i].vbase);
1209         }
1210
1211         kfree(nt->qp_vec);
1212         kfree(nt->mw_vec);
1213         kfree(nt);
1214 }
1215
1216 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1217 {
1218         struct ntb_queue_entry *entry;
1219         void *cb_data;
1220         unsigned int len;
1221         unsigned long irqflags;
1222
1223         spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1224
1225         while (!list_empty(&qp->rx_post_q)) {
1226                 entry = list_first_entry(&qp->rx_post_q,
1227                                          struct ntb_queue_entry, entry);
1228                 if (!(entry->flags & DESC_DONE_FLAG))
1229                         break;
1230
1231                 entry->rx_hdr->flags = 0;
1232                 iowrite32(entry->index, &qp->rx_info->entry);
1233
1234                 cb_data = entry->cb_data;
1235                 len = entry->len;
1236
1237                 list_move_tail(&entry->entry, &qp->rx_free_q);
1238
1239                 spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1240
1241                 if (qp->rx_handler && qp->client_ready)
1242                         qp->rx_handler(qp, qp->cb_data, cb_data, len);
1243
1244                 spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1245         }
1246
1247         spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1248 }
1249
1250 static void ntb_rx_copy_callback(void *data)
1251 {
1252         struct ntb_queue_entry *entry = data;
1253
1254         entry->flags |= DESC_DONE_FLAG;
1255
1256         ntb_complete_rxc(entry->qp);
1257 }
1258
1259 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1260 {
1261         void *buf = entry->buf;
1262         size_t len = entry->len;
1263
1264         memcpy(buf, offset, len);
1265
1266         /* Ensure that the data is fully copied out before clearing the flag */
1267         wmb();
1268
1269         ntb_rx_copy_callback(entry);
1270 }
1271
1272 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1273 {
1274         struct dma_async_tx_descriptor *txd;
1275         struct ntb_transport_qp *qp = entry->qp;
1276         struct dma_chan *chan = qp->rx_dma_chan;
1277         struct dma_device *device;
1278         size_t pay_off, buff_off, len;
1279         struct dmaengine_unmap_data *unmap;
1280         dma_cookie_t cookie;
1281         void *buf = entry->buf;
1282         int retries = 0;
1283
1284         len = entry->len;
1285
1286         if (!chan)
1287                 goto err;
1288
1289         if (len < copy_bytes)
1290                 goto err;
1291
1292         device = chan->device;
1293         pay_off = (size_t)offset & ~PAGE_MASK;
1294         buff_off = (size_t)buf & ~PAGE_MASK;
1295
1296         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1297                 goto err;
1298
1299         unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1300         if (!unmap)
1301                 goto err;
1302
1303         unmap->len = len;
1304         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1305                                       pay_off, len, DMA_TO_DEVICE);
1306         if (dma_mapping_error(device->dev, unmap->addr[0]))
1307                 goto err_get_unmap;
1308
1309         unmap->to_cnt = 1;
1310
1311         unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1312                                       buff_off, len, DMA_FROM_DEVICE);
1313         if (dma_mapping_error(device->dev, unmap->addr[1]))
1314                 goto err_get_unmap;
1315
1316         unmap->from_cnt = 1;
1317
1318         for (retries = 0; retries < DMA_RETRIES; retries++) {
1319                 txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1320                                                      unmap->addr[0], len,
1321                                                      DMA_PREP_INTERRUPT);
1322                 if (txd)
1323                         break;
1324
1325                 set_current_state(TASK_INTERRUPTIBLE);
1326                 schedule_timeout(DMA_OUT_RESOURCE_TO);
1327         }
1328
1329         if (!txd) {
1330                 qp->dma_rx_prep_err++;
1331                 goto err_get_unmap;
1332         }
1333
1334         txd->callback = ntb_rx_copy_callback;
1335         txd->callback_param = entry;
1336         dma_set_unmap(txd, unmap);
1337
1338         cookie = dmaengine_submit(txd);
1339         if (dma_submit_error(cookie))
1340                 goto err_set_unmap;
1341
1342         dmaengine_unmap_put(unmap);
1343
1344         qp->last_cookie = cookie;
1345
1346         qp->rx_async++;
1347
1348         return;
1349
1350 err_set_unmap:
1351         dmaengine_unmap_put(unmap);
1352 err_get_unmap:
1353         dmaengine_unmap_put(unmap);
1354 err:
1355         ntb_memcpy_rx(entry, offset);
1356         qp->rx_memcpy++;
1357 }
1358
1359 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1360 {
1361         struct ntb_payload_header *hdr;
1362         struct ntb_queue_entry *entry;
1363         void *offset;
1364
1365         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1366         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1367
1368         dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1369                 qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1370
1371         if (!(hdr->flags & DESC_DONE_FLAG)) {
1372                 dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1373                 qp->rx_ring_empty++;
1374                 return -EAGAIN;
1375         }
1376
1377         if (hdr->flags & LINK_DOWN_FLAG) {
1378                 dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1379                 ntb_qp_link_down(qp);
1380                 hdr->flags = 0;
1381                 return -EAGAIN;
1382         }
1383
1384         if (hdr->ver != (u32)qp->rx_pkts) {
1385                 dev_dbg(&qp->ndev->pdev->dev,
1386                         "version mismatch, expected %llu - got %u\n",
1387                         qp->rx_pkts, hdr->ver);
1388                 qp->rx_err_ver++;
1389                 return -EIO;
1390         }
1391
1392         entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1393         if (!entry) {
1394                 dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1395                 qp->rx_err_no_buf++;
1396                 return -EAGAIN;
1397         }
1398
1399         entry->rx_hdr = hdr;
1400         entry->index = qp->rx_index;
1401
1402         if (hdr->len > entry->len) {
1403                 dev_dbg(&qp->ndev->pdev->dev,
1404                         "receive buffer overflow! Wanted %d got %d\n",
1405                         hdr->len, entry->len);
1406                 qp->rx_err_oflow++;
1407
1408                 entry->len = -EIO;
1409                 entry->flags |= DESC_DONE_FLAG;
1410
1411                 ntb_complete_rxc(qp);
1412         } else {
1413                 dev_dbg(&qp->ndev->pdev->dev,
1414                         "RX OK index %u ver %u size %d into buf size %d\n",
1415                         qp->rx_index, hdr->ver, hdr->len, entry->len);
1416
1417                 qp->rx_bytes += hdr->len;
1418                 qp->rx_pkts++;
1419
1420                 entry->len = hdr->len;
1421
1422                 ntb_async_rx(entry, offset);
1423         }
1424
1425         qp->rx_index++;
1426         qp->rx_index %= qp->rx_max_entry;
1427
1428         return 0;
1429 }
1430
1431 static void ntb_transport_rxc_db(unsigned long data)
1432 {
1433         struct ntb_transport_qp *qp = (void *)data;
1434         int rc, i;
1435
1436         dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1437                 __func__, qp->qp_num);
1438
1439         /* Limit the number of packets processed in a single interrupt to
1440          * provide fairness to others
1441          */
1442         for (i = 0; i < qp->rx_max_entry; i++) {
1443                 rc = ntb_process_rxc(qp);
1444                 if (rc)
1445                         break;
1446         }
1447
1448         if (i && qp->rx_dma_chan)
1449                 dma_async_issue_pending(qp->rx_dma_chan);
1450
1451         if (i == qp->rx_max_entry) {
1452                 /* there is more work to do */
1453                 if (qp->active)
1454                         tasklet_schedule(&qp->rxc_db_work);
1455         } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1456                 /* the doorbell bit is set: clear it */
1457                 ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1458                 /* ntb_db_read ensures ntb_db_clear write is committed */
1459                 ntb_db_read(qp->ndev);
1460
1461                 /* an interrupt may have arrived between finishing
1462                  * ntb_process_rxc and clearing the doorbell bit:
1463                  * there might be some more work to do.
1464                  */
1465                 if (qp->active)
1466                         tasklet_schedule(&qp->rxc_db_work);
1467         }
1468 }
1469
1470 static void ntb_tx_copy_callback(void *data)
1471 {
1472         struct ntb_queue_entry *entry = data;
1473         struct ntb_transport_qp *qp = entry->qp;
1474         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1475
1476         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1477
1478         ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1479
1480         /* The entry length can only be zero if the packet is intended to be a
1481          * "link down" or similar.  Since no payload is being sent in these
1482          * cases, there is nothing to add to the completion queue.
1483          */
1484         if (entry->len > 0) {
1485                 qp->tx_bytes += entry->len;
1486
1487                 if (qp->tx_handler)
1488                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1489                                        entry->len);
1490         }
1491
1492         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1493 }
1494
1495 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1496 {
1497 #ifdef ARCH_HAS_NOCACHE_UACCESS
1498         /*
1499          * Using non-temporal mov to improve performance on non-cached
1500          * writes, even though we aren't actually copying from user space.
1501          */
1502         __copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1503 #else
1504         memcpy_toio(offset, entry->buf, entry->len);
1505 #endif
1506
1507         /* Ensure that the data is fully copied out before setting the flags */
1508         wmb();
1509
1510         ntb_tx_copy_callback(entry);
1511 }
1512
1513 static void ntb_async_tx(struct ntb_transport_qp *qp,
1514                          struct ntb_queue_entry *entry)
1515 {
1516         struct ntb_payload_header __iomem *hdr;
1517         struct dma_async_tx_descriptor *txd;
1518         struct dma_chan *chan = qp->tx_dma_chan;
1519         struct dma_device *device;
1520         size_t dest_off, buff_off;
1521         struct dmaengine_unmap_data *unmap;
1522         dma_addr_t dest;
1523         dma_cookie_t cookie;
1524         void __iomem *offset;
1525         size_t len = entry->len;
1526         void *buf = entry->buf;
1527         int retries = 0;
1528
1529         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1530         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1531         entry->tx_hdr = hdr;
1532
1533         iowrite32(entry->len, &hdr->len);
1534         iowrite32((u32)qp->tx_pkts, &hdr->ver);
1535
1536         if (!chan)
1537                 goto err;
1538
1539         if (len < copy_bytes)
1540                 goto err;
1541
1542         device = chan->device;
1543         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1544         buff_off = (size_t)buf & ~PAGE_MASK;
1545         dest_off = (size_t)dest & ~PAGE_MASK;
1546
1547         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1548                 goto err;
1549
1550         unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1551         if (!unmap)
1552                 goto err;
1553
1554         unmap->len = len;
1555         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1556                                       buff_off, len, DMA_TO_DEVICE);
1557         if (dma_mapping_error(device->dev, unmap->addr[0]))
1558                 goto err_get_unmap;
1559
1560         unmap->to_cnt = 1;
1561
1562         for (retries = 0; retries < DMA_RETRIES; retries++) {
1563                 txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0],
1564                                                      len, DMA_PREP_INTERRUPT);
1565                 if (txd)
1566                         break;
1567
1568                 set_current_state(TASK_INTERRUPTIBLE);
1569                 schedule_timeout(DMA_OUT_RESOURCE_TO);
1570         }
1571
1572         if (!txd) {
1573                 qp->dma_tx_prep_err++;
1574                 goto err_get_unmap;
1575         }
1576
1577         txd->callback = ntb_tx_copy_callback;
1578         txd->callback_param = entry;
1579         dma_set_unmap(txd, unmap);
1580
1581         cookie = dmaengine_submit(txd);
1582         if (dma_submit_error(cookie))
1583                 goto err_set_unmap;
1584
1585         dmaengine_unmap_put(unmap);
1586
1587         dma_async_issue_pending(chan);
1588         qp->tx_async++;
1589
1590         return;
1591 err_set_unmap:
1592         dmaengine_unmap_put(unmap);
1593 err_get_unmap:
1594         dmaengine_unmap_put(unmap);
1595 err:
1596         ntb_memcpy_tx(entry, offset);
1597         qp->tx_memcpy++;
1598 }
1599
1600 static int ntb_process_tx(struct ntb_transport_qp *qp,
1601                           struct ntb_queue_entry *entry)
1602 {
1603         if (qp->tx_index == qp->remote_rx_info->entry) {
1604                 qp->tx_ring_full++;
1605                 return -EAGAIN;
1606         }
1607
1608         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1609                 if (qp->tx_handler)
1610                         qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
1611
1612                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1613                              &qp->tx_free_q);
1614                 return 0;
1615         }
1616
1617         ntb_async_tx(qp, entry);
1618
1619         qp->tx_index++;
1620         qp->tx_index %= qp->tx_max_entry;
1621
1622         qp->tx_pkts++;
1623
1624         return 0;
1625 }
1626
1627 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1628 {
1629         struct pci_dev *pdev = qp->ndev->pdev;
1630         struct ntb_queue_entry *entry;
1631         int i, rc;
1632
1633         if (!qp->link_is_up)
1634                 return;
1635
1636         dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1637
1638         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1639                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1640                 if (entry)
1641                         break;
1642                 msleep(100);
1643         }
1644
1645         if (!entry)
1646                 return;
1647
1648         entry->cb_data = NULL;
1649         entry->buf = NULL;
1650         entry->len = 0;
1651         entry->flags = LINK_DOWN_FLAG;
1652
1653         rc = ntb_process_tx(qp, entry);
1654         if (rc)
1655                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1656                         qp->qp_num);
1657
1658         ntb_qp_link_down_reset(qp);
1659 }
1660
1661 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1662 {
1663         return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1664 }
1665
1666 /**
1667  * ntb_transport_create_queue - Create a new NTB transport layer queue
1668  * @rx_handler: receive callback function
1669  * @tx_handler: transmit callback function
1670  * @event_handler: event callback function
1671  *
1672  * Create a new NTB transport layer queue and provide the queue with a callback
1673  * routine for both transmit and receive.  The receive callback routine will be
1674  * used to pass up data when the transport has received it on the queue.   The
1675  * transmit callback routine will be called when the transport has completed the
1676  * transmission of the data on the queue and the data is ready to be freed.
1677  *
1678  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1679  */
1680 struct ntb_transport_qp *
1681 ntb_transport_create_queue(void *data, struct device *client_dev,
1682                            const struct ntb_queue_handlers *handlers)
1683 {
1684         struct ntb_dev *ndev;
1685         struct pci_dev *pdev;
1686         struct ntb_transport_ctx *nt;
1687         struct ntb_queue_entry *entry;
1688         struct ntb_transport_qp *qp;
1689         u64 qp_bit;
1690         unsigned int free_queue;
1691         dma_cap_mask_t dma_mask;
1692         int node;
1693         int i;
1694
1695         ndev = dev_ntb(client_dev->parent);
1696         pdev = ndev->pdev;
1697         nt = ndev->ctx;
1698
1699         node = dev_to_node(&ndev->dev);
1700
1701         free_queue = ffs(nt->qp_bitmap);
1702         if (!free_queue)
1703                 goto err;
1704
1705         /* decrement free_queue to make it zero based */
1706         free_queue--;
1707
1708         qp = &nt->qp_vec[free_queue];
1709         qp_bit = BIT_ULL(qp->qp_num);
1710
1711         nt->qp_bitmap_free &= ~qp_bit;
1712
1713         qp->cb_data = data;
1714         qp->rx_handler = handlers->rx_handler;
1715         qp->tx_handler = handlers->tx_handler;
1716         qp->event_handler = handlers->event_handler;
1717
1718         dma_cap_zero(dma_mask);
1719         dma_cap_set(DMA_MEMCPY, dma_mask);
1720
1721         if (use_dma) {
1722                 qp->tx_dma_chan =
1723                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1724                                             (void *)(unsigned long)node);
1725                 if (!qp->tx_dma_chan)
1726                         dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
1727
1728                 qp->rx_dma_chan =
1729                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1730                                             (void *)(unsigned long)node);
1731                 if (!qp->rx_dma_chan)
1732                         dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
1733         } else {
1734                 qp->tx_dma_chan = NULL;
1735                 qp->rx_dma_chan = NULL;
1736         }
1737
1738         dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
1739                 qp->tx_dma_chan ? "DMA" : "CPU");
1740
1741         dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
1742                 qp->rx_dma_chan ? "DMA" : "CPU");
1743
1744         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1745                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1746                 if (!entry)
1747                         goto err1;
1748
1749                 entry->qp = qp;
1750                 ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
1751                              &qp->rx_free_q);
1752         }
1753         qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;
1754
1755         for (i = 0; i < qp->tx_max_entry; i++) {
1756                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1757                 if (!entry)
1758                         goto err2;
1759
1760                 entry->qp = qp;
1761                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1762                              &qp->tx_free_q);
1763         }
1764
1765         ntb_db_clear(qp->ndev, qp_bit);
1766         ntb_db_clear_mask(qp->ndev, qp_bit);
1767
1768         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1769
1770         return qp;
1771
1772 err2:
1773         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1774                 kfree(entry);
1775 err1:
1776         qp->rx_alloc_entry = 0;
1777         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1778                 kfree(entry);
1779         if (qp->tx_dma_chan)
1780                 dma_release_channel(qp->tx_dma_chan);
1781         if (qp->rx_dma_chan)
1782                 dma_release_channel(qp->rx_dma_chan);
1783         nt->qp_bitmap_free |= qp_bit;
1784 err:
1785         return NULL;
1786 }
1787 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1788
1789 /**
1790  * ntb_transport_free_queue - Frees NTB transport queue
1791  * @qp: NTB queue to be freed
1792  *
1793  * Frees NTB transport queue
1794  */
1795 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1796 {
1797         struct pci_dev *pdev;
1798         struct ntb_queue_entry *entry;
1799         u64 qp_bit;
1800
1801         if (!qp)
1802                 return;
1803
1804         pdev = qp->ndev->pdev;
1805
1806         qp->active = false;
1807
1808         if (qp->tx_dma_chan) {
1809                 struct dma_chan *chan = qp->tx_dma_chan;
1810                 /* Putting the dma_chan to NULL will force any new traffic to be
1811                  * processed by the CPU instead of the DAM engine
1812                  */
1813                 qp->tx_dma_chan = NULL;
1814
1815                 /* Try to be nice and wait for any queued DMA engine
1816                  * transactions to process before smashing it with a rock
1817                  */
1818                 dma_sync_wait(chan, qp->last_cookie);
1819                 dmaengine_terminate_all(chan);
1820                 dma_release_channel(chan);
1821         }
1822
1823         if (qp->rx_dma_chan) {
1824                 struct dma_chan *chan = qp->rx_dma_chan;
1825                 /* Putting the dma_chan to NULL will force any new traffic to be
1826                  * processed by the CPU instead of the DAM engine
1827                  */
1828                 qp->rx_dma_chan = NULL;
1829
1830                 /* Try to be nice and wait for any queued DMA engine
1831                  * transactions to process before smashing it with a rock
1832                  */
1833                 dma_sync_wait(chan, qp->last_cookie);
1834                 dmaengine_terminate_all(chan);
1835                 dma_release_channel(chan);
1836         }
1837
1838         qp_bit = BIT_ULL(qp->qp_num);
1839
1840         ntb_db_set_mask(qp->ndev, qp_bit);
1841         tasklet_kill(&qp->rxc_db_work);
1842
1843         cancel_delayed_work_sync(&qp->link_work);
1844
1845         qp->cb_data = NULL;
1846         qp->rx_handler = NULL;
1847         qp->tx_handler = NULL;
1848         qp->event_handler = NULL;
1849
1850         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1851                 kfree(entry);
1852
1853         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
1854                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
1855                 kfree(entry);
1856         }
1857
1858         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
1859                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
1860                 kfree(entry);
1861         }
1862
1863         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1864                 kfree(entry);
1865
1866         qp->transport->qp_bitmap_free |= qp_bit;
1867
1868         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1869 }
1870 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1871
1872 /**
1873  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1874  * @qp: NTB queue to be freed
1875  * @len: pointer to variable to write enqueued buffers length
1876  *
1877  * Dequeues unused buffers from receive queue.  Should only be used during
1878  * shutdown of qp.
1879  *
1880  * RETURNS: NULL error value on error, or void* for success.
1881  */
1882 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1883 {
1884         struct ntb_queue_entry *entry;
1885         void *buf;
1886
1887         if (!qp || qp->client_ready)
1888                 return NULL;
1889
1890         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
1891         if (!entry)
1892                 return NULL;
1893
1894         buf = entry->cb_data;
1895         *len = entry->len;
1896
1897         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
1898
1899         return buf;
1900 }
1901 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1902
1903 /**
1904  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1905  * @qp: NTB transport layer queue the entry is to be enqueued on
1906  * @cb: per buffer pointer for callback function to use
1907  * @data: pointer to data buffer that incoming packets will be copied into
1908  * @len: length of the data buffer
1909  *
1910  * Enqueue a new receive buffer onto the transport queue into which a NTB
1911  * payload can be received into.
1912  *
1913  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1914  */
1915 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1916                              unsigned int len)
1917 {
1918         struct ntb_queue_entry *entry;
1919
1920         if (!qp)
1921                 return -EINVAL;
1922
1923         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
1924         if (!entry)
1925                 return -ENOMEM;
1926
1927         entry->cb_data = cb;
1928         entry->buf = data;
1929         entry->len = len;
1930         entry->flags = 0;
1931
1932         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
1933
1934         if (qp->active)
1935                 tasklet_schedule(&qp->rxc_db_work);
1936
1937         return 0;
1938 }
1939 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1940
1941 /**
1942  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1943  * @qp: NTB transport layer queue the entry is to be enqueued on
1944  * @cb: per buffer pointer for callback function to use
1945  * @data: pointer to data buffer that will be sent
1946  * @len: length of the data buffer
1947  *
1948  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1949  * payload will be transmitted.  This assumes that a lock is being held to
1950  * serialize access to the qp.
1951  *
1952  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1953  */
1954 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1955                              unsigned int len)
1956 {
1957         struct ntb_queue_entry *entry;
1958         int rc;
1959
1960         if (!qp || !qp->link_is_up || !len)
1961                 return -EINVAL;
1962
1963         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1964         if (!entry) {
1965                 qp->tx_err_no_buf++;
1966                 return -EBUSY;
1967         }
1968
1969         entry->cb_data = cb;
1970         entry->buf = data;
1971         entry->len = len;
1972         entry->flags = 0;
1973
1974         rc = ntb_process_tx(qp, entry);
1975         if (rc)
1976                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1977                              &qp->tx_free_q);
1978
1979         return rc;
1980 }
1981 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1982
1983 /**
1984  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1985  * @qp: NTB transport layer queue to be enabled
1986  *
1987  * Notify NTB transport layer of client readiness to use queue
1988  */
1989 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1990 {
1991         if (!qp)
1992                 return;
1993
1994         qp->client_ready = true;
1995
1996         if (qp->transport->link_is_up)
1997                 schedule_delayed_work(&qp->link_work, 0);
1998 }
1999 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
2000
2001 /**
2002  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
2003  * @qp: NTB transport layer queue to be disabled
2004  *
2005  * Notify NTB transport layer of client's desire to no longer receive data on
2006  * transport queue specified.  It is the client's responsibility to ensure all
2007  * entries on queue are purged or otherwise handled appropriately.
2008  */
2009 void ntb_transport_link_down(struct ntb_transport_qp *qp)
2010 {
2011         int val;
2012
2013         if (!qp)
2014                 return;
2015
2016         qp->client_ready = false;
2017
2018         val = ntb_spad_read(qp->ndev, QP_LINKS);
2019
2020         ntb_peer_spad_write(qp->ndev, QP_LINKS,
2021                             val & ~BIT(qp->qp_num));
2022
2023         if (qp->link_is_up)
2024                 ntb_send_link_down(qp);
2025         else
2026                 cancel_delayed_work_sync(&qp->link_work);
2027 }
2028 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
2029
2030 /**
2031  * ntb_transport_link_query - Query transport link state
2032  * @qp: NTB transport layer queue to be queried
2033  *
2034  * Query connectivity to the remote system of the NTB transport queue
2035  *
2036  * RETURNS: true for link up or false for link down
2037  */
2038 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
2039 {
2040         if (!qp)
2041                 return false;
2042
2043         return qp->link_is_up;
2044 }
2045 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
2046
2047 /**
2048  * ntb_transport_qp_num - Query the qp number
2049  * @qp: NTB transport layer queue to be queried
2050  *
2051  * Query qp number of the NTB transport queue
2052  *
2053  * RETURNS: a zero based number specifying the qp number
2054  */
2055 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
2056 {
2057         if (!qp)
2058                 return 0;
2059
2060         return qp->qp_num;
2061 }
2062 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
2063
2064 /**
2065  * ntb_transport_max_size - Query the max payload size of a qp
2066  * @qp: NTB transport layer queue to be queried
2067  *
2068  * Query the maximum payload size permissible on the given qp
2069  *
2070  * RETURNS: the max payload size of a qp
2071  */
2072 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
2073 {
2074         unsigned int max_size;
2075         unsigned int copy_align;
2076         struct dma_chan *rx_chan, *tx_chan;
2077
2078         if (!qp)
2079                 return 0;
2080
2081         rx_chan = qp->rx_dma_chan;
2082         tx_chan = qp->tx_dma_chan;
2083
2084         copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
2085                          tx_chan ? tx_chan->device->copy_align : 0);
2086
2087         /* If DMA engine usage is possible, try to find the max size for that */
2088         max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
2089         max_size = round_down(max_size, 1 << copy_align);
2090
2091         return max_size;
2092 }
2093 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
2094
2095 unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
2096 {
2097         unsigned int head = qp->tx_index;
2098         unsigned int tail = qp->remote_rx_info->entry;
2099
2100         return tail > head ? tail - head : qp->tx_max_entry + tail - head;
2101 }
2102 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
2103
2104 static void ntb_transport_doorbell_callback(void *data, int vector)
2105 {
2106         struct ntb_transport_ctx *nt = data;
2107         struct ntb_transport_qp *qp;
2108         u64 db_bits;
2109         unsigned int qp_num;
2110
2111         db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
2112                    ntb_db_vector_mask(nt->ndev, vector));
2113
2114         while (db_bits) {
2115                 qp_num = __ffs(db_bits);
2116                 qp = &nt->qp_vec[qp_num];
2117
2118                 if (qp->active)
2119                         tasklet_schedule(&qp->rxc_db_work);
2120
2121                 db_bits &= ~BIT_ULL(qp_num);
2122         }
2123 }
2124
2125 static const struct ntb_ctx_ops ntb_transport_ops = {
2126         .link_event = ntb_transport_event_callback,
2127         .db_event = ntb_transport_doorbell_callback,
2128 };
2129
2130 static struct ntb_client ntb_transport_client = {
2131         .ops = {
2132                 .probe = ntb_transport_probe,
2133                 .remove = ntb_transport_free,
2134         },
2135 };
2136
2137 static int __init ntb_transport_init(void)
2138 {
2139         int rc;
2140
2141         pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2142
2143         if (debugfs_initialized())
2144                 nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2145
2146         rc = bus_register(&ntb_transport_bus);
2147         if (rc)
2148                 goto err_bus;
2149
2150         rc = ntb_register_client(&ntb_transport_client);
2151         if (rc)
2152                 goto err_client;
2153
2154         return 0;
2155
2156 err_client:
2157         bus_unregister(&ntb_transport_bus);
2158 err_bus:
2159         debugfs_remove_recursive(nt_debugfs_dir);
2160         return rc;
2161 }
2162 module_init(ntb_transport_init);
2163
2164 static void __exit ntb_transport_exit(void)
2165 {
2166         debugfs_remove_recursive(nt_debugfs_dir);
2167
2168         ntb_unregister_client(&ntb_transport_client);
2169         bus_unregister(&ntb_transport_bus);
2170 }
2171 module_exit(ntb_transport_exit);