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/ntb.h"
  62 #include "linux/ntb_transport.h"
  63
  64 #define NTB_TRANSPORT_VERSION   4
  65 #define NTB_TRANSPORT_VER       "4"
  66 #define NTB_TRANSPORT_NAME      "ntb_transport"
  67 #define NTB_TRANSPORT_DESC      "Software Queue-Pair Transport over NTB"
  68
  69 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
  70 MODULE_VERSION(NTB_TRANSPORT_VER);
  71 MODULE_LICENSE("Dual BSD/GPL");
  72 MODULE_AUTHOR("Intel Corporation");
  73
  74 static unsigned long max_mw_size;
  75 module_param(max_mw_size, ulong, 0644);
  76 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
  77
  78 static unsigned int transport_mtu = 0x401E;
  79 module_param(transport_mtu, uint, 0644);
  80 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
  81
  82 static unsigned char max_num_clients;
  83 module_param(max_num_clients, byte, 0644);
  84 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
  85
  86 static unsigned int copy_bytes = 1024;
  87 module_param(copy_bytes, uint, 0644);
  88 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
  89
  90 static struct dentry *nt_debugfs_dir;
  91
  92 struct ntb_queue_entry {
  93         /* ntb_queue list reference */
  94         struct list_head entry;
  95         /* pointers to data to be transferred */
  96         void *cb_data;
  97         void *buf;
  98         unsigned int len;
  99         unsigned int flags;
 100
 101         struct ntb_transport_qp *qp;
 102         union {
 103                 struct ntb_payload_header __iomem *tx_hdr;
 104                 struct ntb_payload_header *rx_hdr;
 105         };
 106         unsigned int index;
 107 };
 108
 109 struct ntb_rx_info {
 110         unsigned int entry;
 111 };
 112
 113 struct ntb_transport_qp {
 114         struct ntb_transport_ctx *transport;
 115         struct ntb_dev *ndev;
 116         void *cb_data;
 117         struct dma_chan *dma_chan;
 118
 119         bool client_ready;
 120         bool link_is_up;
 121
 122         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 123         u64 qp_bit;
 124
 125         struct ntb_rx_info __iomem *rx_info;
 126         struct ntb_rx_info *remote_rx_info;
 127
 128         void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 129                            void *data, int len);
 130         struct list_head tx_free_q;
 131         spinlock_t ntb_tx_free_q_lock;
 132         void __iomem *tx_mw;
 133         dma_addr_t tx_mw_phys;
 134         unsigned int tx_index;
 135         unsigned int tx_max_entry;
 136         unsigned int tx_max_frame;
 137
 138         void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 139                            void *data, int len);
 140         struct list_head rx_pend_q;
 141         struct list_head rx_free_q;
 142         spinlock_t ntb_rx_pend_q_lock;
 143         spinlock_t ntb_rx_free_q_lock;
 144         void *rx_buff;
 145         unsigned int rx_index;
 146         unsigned int rx_max_entry;
 147         unsigned int rx_max_frame;
 148         dma_cookie_t last_cookie;
 149         struct tasklet_struct rxc_db_work;
 150
 151         void (*event_handler)(void *data, int status);
 152         struct delayed_work link_work;
 153         struct work_struct link_cleanup;
 154
 155         struct dentry *debugfs_dir;
 156         struct dentry *debugfs_stats;
 157
 158         /* Stats */
 159         u64 rx_bytes;
 160         u64 rx_pkts;
 161         u64 rx_ring_empty;
 162         u64 rx_err_no_buf;
 163         u64 rx_err_oflow;
 164         u64 rx_err_ver;
 165         u64 rx_memcpy;
 166         u64 rx_async;
 167         u64 tx_bytes;
 168         u64 tx_pkts;
 169         u64 tx_ring_full;
 170         u64 tx_err_no_buf;
 171         u64 tx_memcpy;
 172         u64 tx_async;
 173 };
 174
 175 struct ntb_transport_mw {
 176         phys_addr_t phys_addr;
 177         resource_size_t phys_size;
 178         resource_size_t xlat_align;
 179         resource_size_t xlat_align_size;
 180         void __iomem *vbase;
 181         size_t xlat_size;
 182         size_t buff_size;
 183         void *virt_addr;
 184         dma_addr_t dma_addr;
 185 };
 186
 187 struct ntb_transport_client_dev {
 188         struct list_head entry;
 189         struct ntb_transport_ctx *nt;
 190         struct device dev;
 191 };
 192
 193 struct ntb_transport_ctx {
 194         struct list_head entry;
 195         struct list_head client_devs;
 196
 197         struct ntb_dev *ndev;
 198
 199         struct ntb_transport_mw *mw_vec;
 200         struct ntb_transport_qp *qp_vec;
 201         unsigned int mw_count;
 202         unsigned int qp_count;
 203         u64 qp_bitmap;
 204         u64 qp_bitmap_free;
 205
 206         bool link_is_up;
 207         struct delayed_work link_work;
 208         struct work_struct link_cleanup;
 209 };
 210
 211 enum {
 212         DESC_DONE_FLAG = BIT(0),
 213         LINK_DOWN_FLAG = BIT(1),
 214 };
 215
 216 struct ntb_payload_header {
 217         unsigned int ver;
 218         unsigned int len;
 219         unsigned int flags;
 220 };
 221
 222 enum {
 223         VERSION = 0,
 224         QP_LINKS,
 225         NUM_QPS,
 226         NUM_MWS,
 227         MW0_SZ_HIGH,
 228         MW0_SZ_LOW,
 229         MW1_SZ_HIGH,
 230         MW1_SZ_LOW,
 231         MAX_SPAD,
 232 };
 233
 234 #define dev_client_dev(__dev) \
 235         container_of((__dev), struct ntb_transport_client_dev, dev)
 236
 237 #define drv_client(__drv) \
 238         container_of((__drv), struct ntb_transport_client, driver)
 239
 240 #define QP_TO_MW(nt, qp)        ((qp) % nt->mw_count)
 241 #define NTB_QP_DEF_NUM_ENTRIES  100
 242 #define NTB_LINK_DOWN_TIMEOUT   10
 243
 244 static void ntb_transport_rxc_db(unsigned long data);
 245 static const struct ntb_ctx_ops ntb_transport_ops;
 246 static struct ntb_client ntb_transport_client;
 247
 248 static int ntb_transport_bus_match(struct device *dev,
 249                                    struct device_driver *drv)
 250 {
 251         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 252 }
 253
 254 static int ntb_transport_bus_probe(struct device *dev)
 255 {
 256         const struct ntb_transport_client *client;
 257         int rc = -EINVAL;
 258
 259         get_device(dev);
 260
 261         client = drv_client(dev->driver);
 262         rc = client->probe(dev);
 263         if (rc)
 264                 put_device(dev);
 265
 266         return rc;
 267 }
 268
 269 static int ntb_transport_bus_remove(struct device *dev)
 270 {
 271         const struct ntb_transport_client *client;
 272
 273         client = drv_client(dev->driver);
 274         client->remove(dev);
 275
 276         put_device(dev);
 277
 278         return 0;
 279 }
 280
 281 static struct bus_type ntb_transport_bus = {
 282         .name = "ntb_transport",
 283         .match = ntb_transport_bus_match,
 284         .probe = ntb_transport_bus_probe,
 285         .remove = ntb_transport_bus_remove,
 286 };
 287
 288 static LIST_HEAD(ntb_transport_list);
 289
 290 static int ntb_bus_init(struct ntb_transport_ctx *nt)
 291 {
 292         list_add(&nt->entry, &ntb_transport_list);
 293         return 0;
 294 }
 295
 296 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
 297 {
 298         struct ntb_transport_client_dev *client_dev, *cd;
 299
 300         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 301                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 302                         dev_name(&client_dev->dev));
 303                 list_del(&client_dev->entry);
 304                 device_unregister(&client_dev->dev);
 305         }
 306
 307         list_del(&nt->entry);
 308 }
 309
 310 static void ntb_transport_client_release(struct device *dev)
 311 {
 312         struct ntb_transport_client_dev *client_dev;
 313
 314         client_dev = dev_client_dev(dev);
 315         kfree(client_dev);
 316 }
 317
 318 /**
 319  * ntb_transport_unregister_client_dev - Unregister NTB client device
 320  * @device_name: Name of NTB client device
 321  *
 322  * Unregister an NTB client device with the NTB transport layer
 323  */
 324 void ntb_transport_unregister_client_dev(char *device_name)
 325 {
 326         struct ntb_transport_client_dev *client, *cd;
 327         struct ntb_transport_ctx *nt;
 328
 329         list_for_each_entry(nt, &ntb_transport_list, entry)
 330                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 331                         if (!strncmp(dev_name(&client->dev), device_name,
 332                                      strlen(device_name))) {
 333                                 list_del(&client->entry);
 334                                 device_unregister(&client->dev);
 335                         }
 336 }
 337 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
 338
 339 /**
 340  * ntb_transport_register_client_dev - Register NTB client device
 341  * @device_name: Name of NTB client device
 342  *
 343  * Register an NTB client device with the NTB transport layer
 344  */
 345 int ntb_transport_register_client_dev(char *device_name)
 346 {
 347         struct ntb_transport_client_dev *client_dev;
 348         struct ntb_transport_ctx *nt;
 349         int rc, i = 0;
 350
 351         if (list_empty(&ntb_transport_list))
 352                 return -ENODEV;
 353
 354         list_for_each_entry(nt, &ntb_transport_list, entry) {
 355                 struct device *dev;
 356
 357                 client_dev = kzalloc(sizeof(*client_dev),
 358                                      GFP_KERNEL);
 359                 if (!client_dev) {
 360                         rc = -ENOMEM;
 361                         goto err;
 362                 }
 363
 364                 dev = &client_dev->dev;
 365
 366                 /* setup and register client devices */
 367                 dev_set_name(dev, "%s%d", device_name, i);
 368                 dev->bus = &ntb_transport_bus;
 369                 dev->release = ntb_transport_client_release;
 370                 dev->parent = &nt->ndev->dev;
 371
 372                 rc = device_register(dev);
 373                 if (rc) {
 374                         kfree(client_dev);
 375                         goto err;
 376                 }
 377
 378                 list_add_tail(&client_dev->entry, &nt->client_devs);
 379                 i++;
 380         }
 381
 382         return 0;
 383
 384 err:
 385         ntb_transport_unregister_client_dev(device_name);
 386
 387         return rc;
 388 }
 389 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
 390
 391 /**
 392  * ntb_transport_register_client - Register NTB client driver
 393  * @drv: NTB client driver to be registered
 394  *
 395  * Register an NTB client driver with the NTB transport layer
 396  *
 397  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 398  */
 399 int ntb_transport_register_client(struct ntb_transport_client *drv)
 400 {
 401         drv->driver.bus = &ntb_transport_bus;
 402
 403         if (list_empty(&ntb_transport_list))
 404                 return -ENODEV;
 405
 406         return driver_register(&drv->driver);
 407 }
 408 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
 409
 410 /**
 411  * ntb_transport_unregister_client - Unregister NTB client driver
 412  * @drv: NTB client driver to be unregistered
 413  *
 414  * Unregister an NTB client driver with the NTB transport layer
 415  *
 416  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 417  */
 418 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
 419 {
 420         driver_unregister(&drv->driver);
 421 }
 422 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
 423
 424 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 425                             loff_t *offp)
 426 {
 427         struct ntb_transport_qp *qp;
 428         char *buf;
 429         ssize_t ret, out_offset, out_count;
 430
 431         out_count = 1000;
 432
 433         buf = kmalloc(out_count, GFP_KERNEL);
 434         if (!buf)
 435                 return -ENOMEM;
 436
 437         qp = filp->private_data;
 438         out_offset = 0;
 439         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 440                                "NTB QP stats\n");
 441         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 442                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 443         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 444                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 445         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 446                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
 447         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 448                                "rx_async - \t%llu\n", qp->rx_async);
 449         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 450                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 451         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 452                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 453         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 454                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 455         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 456                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 457         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 458                                "rx_buff - \t%p\n", qp->rx_buff);
 459         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 460                                "rx_index - \t%u\n", qp->rx_index);
 461         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 462                                "rx_max_entry - \t%u\n", qp->rx_max_entry);
 463
 464         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 465                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 466         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 467                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 468         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 469                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
 470         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 471                                "tx_async - \t%llu\n", qp->tx_async);
 472         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 473                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 474         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 475                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 476         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 477                                "tx_mw - \t%p\n", qp->tx_mw);
 478         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 479                                "tx_index - \t%u\n", qp->tx_index);
 480         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 481                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
 482
 483         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 484                                "\nQP Link %s\n",
 485                                qp->link_is_up ? "Up" : "Down");
 486         if (out_offset > out_count)
 487                 out_offset = out_count;
 488
 489         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 490         kfree(buf);
 491         return ret;
 492 }
 493
 494 static const struct file_operations ntb_qp_debugfs_stats = {
 495         .owner = THIS_MODULE,
 496         .open = simple_open,
 497         .read = debugfs_read,
 498 };
 499
 500 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 501                          struct list_head *list)
 502 {
 503         unsigned long flags;
 504
 505         spin_lock_irqsave(lock, flags);
 506         list_add_tail(entry, list);
 507         spin_unlock_irqrestore(lock, flags);
 508 }
 509
 510 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 511                                            struct list_head *list)
 512 {
 513         struct ntb_queue_entry *entry;
 514         unsigned long flags;
 515
 516         spin_lock_irqsave(lock, flags);
 517         if (list_empty(list)) {
 518                 entry = NULL;
 519                 goto out;
 520         }
 521         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 522         list_del(&entry->entry);
 523 out:
 524         spin_unlock_irqrestore(lock, flags);
 525
 526         return entry;
 527 }
 528
 529 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 530                                      unsigned int qp_num)
 531 {
 532         struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
 533         struct ntb_transport_mw *mw;
 534         unsigned int rx_size, num_qps_mw;
 535         unsigned int mw_num, mw_count, qp_count;
 536         unsigned int i;
 537
 538         mw_count = nt->mw_count;
 539         qp_count = nt->qp_count;
 540
 541         mw_num = QP_TO_MW(nt, qp_num);
 542         mw = &nt->mw_vec[mw_num];
 543
 544         if (!mw->virt_addr)
 545                 return -ENOMEM;
 546
 547         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 548                 num_qps_mw = qp_count / mw_count + 1;
 549         else
 550                 num_qps_mw = qp_count / mw_count;
 551
 552         rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
 553         qp->rx_buff = mw->virt_addr + rx_size * qp_num / mw_count;
 554         rx_size -= sizeof(struct ntb_rx_info);
 555
 556         qp->remote_rx_info = qp->rx_buff + rx_size;
 557
 558         /* Due to housekeeping, there must be atleast 2 buffs */
 559         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
 560         qp->rx_max_entry = rx_size / qp->rx_max_frame;
 561         qp->rx_index = 0;
 562
 563         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
 564
 565         /* setup the hdr offsets with 0's */
 566         for (i = 0; i < qp->rx_max_entry; i++) {
 567                 void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
 568                                 sizeof(struct ntb_payload_header));
 569                 memset(offset, 0, sizeof(struct ntb_payload_header));
 570         }
 571
 572         qp->rx_pkts = 0;
 573         qp->tx_pkts = 0;
 574         qp->tx_index = 0;
 575
 576         return 0;
 577 }
 578
 579 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 580 {
 581         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 582         struct pci_dev *pdev = nt->ndev->pdev;
 583
 584         if (!mw->virt_addr)
 585                 return;
 586
 587         ntb_mw_clear_trans(nt->ndev, num_mw);
 588         dma_free_coherent(&pdev->dev, mw->buff_size,
 589                           mw->virt_addr, mw->dma_addr);
 590         mw->xlat_size = 0;
 591         mw->buff_size = 0;
 592         mw->virt_addr = NULL;
 593 }
 594
 595 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 596                       unsigned int size)
 597 {
 598         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 599         struct pci_dev *pdev = nt->ndev->pdev;
 600         unsigned int xlat_size, buff_size;
 601         int rc;
 602
 603         xlat_size = round_up(size, mw->xlat_align_size);
 604         buff_size = round_up(size, mw->xlat_align);
 605
 606         /* No need to re-setup */
 607         if (mw->xlat_size == xlat_size)
 608                 return 0;
 609
 610         if (mw->buff_size)
 611                 ntb_free_mw(nt, num_mw);
 612
 613         /* Alloc memory for receiving data.  Must be aligned */
 614         mw->xlat_size = xlat_size;
 615         mw->buff_size = buff_size;
 616
 617         mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
 618                                            &mw->dma_addr, GFP_KERNEL);
 619         if (!mw->virt_addr) {
 620                 mw->xlat_size = 0;
 621                 mw->buff_size = 0;
 622                 dev_err(&pdev->dev, "Unable to alloc MW buff of size %d\n",
 623                         buff_size);
 624                 return -ENOMEM;
 625         }
 626
 627         /*
 628          * we must ensure that the memory address allocated is BAR size
 629          * aligned in order for the XLAT register to take the value. This
 630          * is a requirement of the hardware. It is recommended to setup CMA
 631          * for BAR sizes equal or greater than 4MB.
 632          */
 633         if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
 634                 dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
 635                         &mw->dma_addr);
 636                 ntb_free_mw(nt, num_mw);
 637                 return -ENOMEM;
 638         }
 639
 640         /* Notify HW the memory location of the receive buffer */
 641         rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
 642         if (rc) {
 643                 dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
 644                 ntb_free_mw(nt, num_mw);
 645                 return -EIO;
 646         }
 647
 648         return 0;
 649 }
 650
 651 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 652 {
 653         qp->link_is_up = false;
 654
 655         qp->tx_index = 0;
 656         qp->rx_index = 0;
 657         qp->rx_bytes = 0;
 658         qp->rx_pkts = 0;
 659         qp->rx_ring_empty = 0;
 660         qp->rx_err_no_buf = 0;
 661         qp->rx_err_oflow = 0;
 662         qp->rx_err_ver = 0;
 663         qp->rx_memcpy = 0;
 664         qp->rx_async = 0;
 665         qp->tx_bytes = 0;
 666         qp->tx_pkts = 0;
 667         qp->tx_ring_full = 0;
 668         qp->tx_err_no_buf = 0;
 669         qp->tx_memcpy = 0;
 670         qp->tx_async = 0;
 671 }
 672
 673 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
 674 {
 675         struct ntb_transport_ctx *nt = qp->transport;
 676         struct pci_dev *pdev = nt->ndev->pdev;
 677
 678         dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
 679
 680         cancel_delayed_work_sync(&qp->link_work);
 681         ntb_qp_link_down_reset(qp);
 682
 683         if (qp->event_handler)
 684                 qp->event_handler(qp->cb_data, qp->link_is_up);
 685 }
 686
 687 static void ntb_qp_link_cleanup_work(struct work_struct *work)
 688 {
 689         struct ntb_transport_qp *qp = container_of(work,
 690                                                    struct ntb_transport_qp,
 691                                                    link_cleanup);
 692         struct ntb_transport_ctx *nt = qp->transport;
 693
 694         ntb_qp_link_cleanup(qp);
 695
 696         if (nt->link_is_up)
 697                 schedule_delayed_work(&qp->link_work,
 698                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 699 }
 700
 701 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 702 {
 703         schedule_work(&qp->link_cleanup);
 704 }
 705
 706 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 707 {
 708         struct ntb_transport_qp *qp;
 709         u64 qp_bitmap_alloc;
 710         int i;
 711
 712         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
 713
 714         /* Pass along the info to any clients */
 715         for (i = 0; i < nt->qp_count; i++)
 716                 if (qp_bitmap_alloc & BIT_ULL(i)) {
 717                         qp = &nt->qp_vec[i];
 718                         ntb_qp_link_cleanup(qp);
 719                         cancel_work_sync(&qp->link_cleanup);
 720                         cancel_delayed_work_sync(&qp->link_work);
 721                 }
 722
 723         if (!nt->link_is_up)
 724                 cancel_delayed_work_sync(&nt->link_work);
 725
 726         /* The scratchpad registers keep the values if the remote side
 727          * goes down, blast them now to give them a sane value the next
 728          * time they are accessed
 729          */
 730         for (i = 0; i < MAX_SPAD; i++)
 731                 ntb_spad_write(nt->ndev, i, 0);
 732 }
 733
 734 static void ntb_transport_link_cleanup_work(struct work_struct *work)
 735 {
 736         struct ntb_transport_ctx *nt =
 737                 container_of(work, struct ntb_transport_ctx, link_cleanup);
 738
 739         ntb_transport_link_cleanup(nt);
 740 }
 741
 742 static void ntb_transport_event_callback(void *data)
 743 {
 744         struct ntb_transport_ctx *nt = data;
 745
 746         if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
 747                 schedule_delayed_work(&nt->link_work, 0);
 748         else
 749                 schedule_work(&nt->link_cleanup);
 750 }
 751
 752 static void ntb_transport_link_work(struct work_struct *work)
 753 {
 754         struct ntb_transport_ctx *nt =
 755                 container_of(work, struct ntb_transport_ctx, link_work.work);
 756         struct ntb_dev *ndev = nt->ndev;
 757         struct pci_dev *pdev = ndev->pdev;
 758         resource_size_t size;
 759         u32 val;
 760         int rc, i, spad;
 761
 762         /* send the local info, in the opposite order of the way we read it */
 763         for (i = 0; i < nt->mw_count; i++) {
 764                 size = nt->mw_vec[i].phys_size;
 765
 766                 if (max_mw_size && size > max_mw_size)
 767                         size = max_mw_size;
 768
 769                 spad = MW0_SZ_HIGH + (i * 2);
 770                 ntb_peer_spad_write(ndev, spad, (u32)(size >> 32));
 771
 772                 spad = MW0_SZ_LOW + (i * 2);
 773                 ntb_peer_spad_write(ndev, spad, (u32)size);
 774         }
 775
 776         ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
 777
 778         ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
 779
 780         ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
 781
 782         /* Query the remote side for its info */
 783         val = ntb_spad_read(ndev, VERSION);
 784         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 785         if (val != NTB_TRANSPORT_VERSION)
 786                 goto out;
 787
 788         val = ntb_spad_read(ndev, NUM_QPS);
 789         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 790         if (val != nt->qp_count)
 791                 goto out;
 792
 793         val = ntb_spad_read(ndev, NUM_MWS);
 794         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
 795         if (val != nt->mw_count)
 796                 goto out;
 797
 798         for (i = 0; i < nt->mw_count; i++) {
 799                 u64 val64;
 800
 801                 val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
 802                 val64 = (u64)val << 32;
 803
 804                 val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
 805                 val64 |= val;
 806
 807                 dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
 808
 809                 rc = ntb_set_mw(nt, i, val64);
 810                 if (rc)
 811                         goto out1;
 812         }
 813
 814         nt->link_is_up = true;
 815
 816         for (i = 0; i < nt->qp_count; i++) {
 817                 struct ntb_transport_qp *qp = &nt->qp_vec[i];
 818
 819                 ntb_transport_setup_qp_mw(nt, i);
 820
 821                 if (qp->client_ready)
 822                         schedule_delayed_work(&qp->link_work, 0);
 823         }
 824
 825         return;
 826
 827 out1:
 828         for (i = 0; i < nt->mw_count; i++)
 829                 ntb_free_mw(nt, i);
 830 out:
 831         if (ntb_link_is_up(ndev, NULL, NULL) == 1)
 832                 schedule_delayed_work(&nt->link_work,
 833                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 834 }
 835
 836 static void ntb_qp_link_work(struct work_struct *work)
 837 {
 838         struct ntb_transport_qp *qp = container_of(work,
 839                                                    struct ntb_transport_qp,
 840                                                    link_work.work);
 841         struct pci_dev *pdev = qp->ndev->pdev;
 842         struct ntb_transport_ctx *nt = qp->transport;
 843         int val;
 844
 845         WARN_ON(!nt->link_is_up);
 846
 847         val = ntb_spad_read(nt->ndev, QP_LINKS);
 848
 849         ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
 850
 851         /* query remote spad for qp ready bits */
 852         ntb_peer_spad_read(nt->ndev, QP_LINKS);
 853         dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
 854
 855         /* See if the remote side is up */
 856         if (val & BIT(qp->qp_num)) {
 857                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 858                 qp->link_is_up = true;
 859
 860                 if (qp->event_handler)
 861                         qp->event_handler(qp->cb_data, qp->link_is_up);
 862         } else if (nt->link_is_up)
 863                 schedule_delayed_work(&qp->link_work,
 864                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 865 }
 866
 867 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 868                                     unsigned int qp_num)
 869 {
 870         struct ntb_transport_qp *qp;
 871         struct ntb_transport_mw *mw;
 872         phys_addr_t mw_base;
 873         resource_size_t mw_size;
 874         unsigned int num_qps_mw, tx_size;
 875         unsigned int mw_num, mw_count, qp_count;
 876         u64 qp_offset;
 877
 878         mw_count = nt->mw_count;
 879         qp_count = nt->qp_count;
 880
 881         mw_num = QP_TO_MW(nt, qp_num);
 882         mw = &nt->mw_vec[mw_num];
 883
 884         qp = &nt->qp_vec[qp_num];
 885         qp->qp_num = qp_num;
 886         qp->transport = nt;
 887         qp->ndev = nt->ndev;
 888         qp->client_ready = false;
 889         qp->event_handler = NULL;
 890         ntb_qp_link_down_reset(qp);
 891
 892         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 893                 num_qps_mw = qp_count / mw_count + 1;
 894         else
 895                 num_qps_mw = qp_count / mw_count;
 896
 897         mw_base = nt->mw_vec[mw_num].phys_addr;
 898         mw_size = nt->mw_vec[mw_num].phys_size;
 899
 900         tx_size = (unsigned int)mw_size / num_qps_mw;
 901         qp_offset = tx_size * qp_num / mw_count;
 902
 903         qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
 904         if (!qp->tx_mw)
 905                 return -EINVAL;
 906
 907         qp->tx_mw_phys = mw_base + qp_offset;
 908         if (!qp->tx_mw_phys)
 909                 return -EINVAL;
 910
 911         tx_size -= sizeof(struct ntb_rx_info);
 912         qp->rx_info = qp->tx_mw + tx_size;
 913
 914         /* Due to housekeeping, there must be atleast 2 buffs */
 915         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 916         qp->tx_max_entry = tx_size / qp->tx_max_frame;
 917
 918         if (nt_debugfs_dir) {
 919                 char debugfs_name[4];
 920
 921                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 922                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 923                                                      nt_debugfs_dir);
 924
 925                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 926                                                         qp->debugfs_dir, qp,
 927                                                         &ntb_qp_debugfs_stats);
 928         } else {
 929                 qp->debugfs_dir = NULL;
 930                 qp->debugfs_stats = NULL;
 931         }
 932
 933         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 934         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
 935
 936         spin_lock_init(&qp->ntb_rx_pend_q_lock);
 937         spin_lock_init(&qp->ntb_rx_free_q_lock);
 938         spin_lock_init(&qp->ntb_tx_free_q_lock);
 939
 940         INIT_LIST_HEAD(&qp->rx_pend_q);
 941         INIT_LIST_HEAD(&qp->rx_free_q);
 942         INIT_LIST_HEAD(&qp->tx_free_q);
 943
 944         tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
 945                      (unsigned long)qp);
 946
 947         return 0;
 948 }
 949
 950 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 951 {
 952         struct ntb_transport_ctx *nt;
 953         struct ntb_transport_mw *mw;
 954         unsigned int mw_count, qp_count;
 955         u64 qp_bitmap;
 956         int rc, i;
 957
 958         if (ntb_db_is_unsafe(ndev))
 959                 dev_dbg(&ndev->dev,
 960                         "doorbell is unsafe, proceed anyway...\n");
 961         if (ntb_spad_is_unsafe(ndev))
 962                 dev_dbg(&ndev->dev,
 963                         "scratchpad is unsafe, proceed anyway...\n");
 964
 965         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 966         if (!nt)
 967                 return -ENOMEM;
 968
 969         nt->ndev = ndev;
 970
 971         mw_count = ntb_mw_count(ndev);
 972
 973         nt->mw_count = mw_count;
 974
 975         nt->mw_vec = kcalloc(mw_count, sizeof(*nt->mw_vec), GFP_KERNEL);
 976         if (!nt->mw_vec) {
 977                 rc = -ENOMEM;
 978                 goto err;
 979         }
 980
 981         for (i = 0; i < mw_count; i++) {
 982                 mw = &nt->mw_vec[i];
 983
 984                 rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
 985                                       &mw->xlat_align, &mw->xlat_align_size);
 986                 if (rc)
 987                         goto err1;
 988
 989                 mw->vbase = ioremap(mw->phys_addr, mw->phys_size);
 990                 if (!mw->vbase) {
 991                         rc = -ENOMEM;
 992                         goto err1;
 993                 }
 994
 995                 mw->buff_size = 0;
 996                 mw->xlat_size = 0;
 997                 mw->virt_addr = NULL;
 998                 mw->dma_addr = 0;
 999         }
1000
1001         qp_bitmap = ntb_db_valid_mask(ndev);
1002
1003         qp_count = ilog2(qp_bitmap);
1004         if (max_num_clients && max_num_clients < qp_count)
1005                 qp_count = max_num_clients;
1006         else if (mw_count < qp_count)
1007                 qp_count = mw_count;
1008
1009         qp_bitmap &= BIT_ULL(qp_count) - 1;
1010
1011         nt->qp_count = qp_count;
1012         nt->qp_bitmap = qp_bitmap;
1013         nt->qp_bitmap_free = qp_bitmap;
1014
1015         nt->qp_vec = kcalloc(qp_count, sizeof(*nt->qp_vec), GFP_KERNEL);
1016         if (!nt->qp_vec) {
1017                 rc = -ENOMEM;
1018                 goto err2;
1019         }
1020
1021         for (i = 0; i < qp_count; i++) {
1022                 rc = ntb_transport_init_queue(nt, i);
1023                 if (rc)
1024                         goto err3;
1025         }
1026
1027         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1028         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1029
1030         rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1031         if (rc)
1032                 goto err3;
1033
1034         INIT_LIST_HEAD(&nt->client_devs);
1035         rc = ntb_bus_init(nt);
1036         if (rc)
1037                 goto err4;
1038
1039         nt->link_is_up = false;
1040         ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1041         ntb_link_event(ndev);
1042
1043         return 0;
1044
1045 err4:
1046         ntb_clear_ctx(ndev);
1047 err3:
1048         kfree(nt->qp_vec);
1049 err2:
1050         kfree(nt->mw_vec);
1051 err1:
1052         while (i--) {
1053                 mw = &nt->mw_vec[i];
1054                 iounmap(mw->vbase);
1055         }
1056 err:
1057         kfree(nt);
1058         return rc;
1059 }
1060
1061 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1062 {
1063         struct ntb_transport_ctx *nt = ndev->ctx;
1064         struct ntb_transport_qp *qp;
1065         u64 qp_bitmap_alloc;
1066         int i;
1067
1068         ntb_transport_link_cleanup(nt);
1069         cancel_work_sync(&nt->link_cleanup);
1070         cancel_delayed_work_sync(&nt->link_work);
1071
1072         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1073
1074         /* verify that all the qp's are freed */
1075         for (i = 0; i < nt->qp_count; i++) {
1076                 qp = &nt->qp_vec[i];
1077                 if (qp_bitmap_alloc & BIT_ULL(i))
1078                         ntb_transport_free_queue(qp);
1079                 debugfs_remove_recursive(qp->debugfs_dir);
1080         }
1081
1082         ntb_link_disable(ndev);
1083         ntb_clear_ctx(ndev);
1084
1085         ntb_bus_remove(nt);
1086
1087         for (i = nt->mw_count; i--; ) {
1088                 ntb_free_mw(nt, i);
1089                 iounmap(nt->mw_vec[i].vbase);
1090         }
1091
1092         kfree(nt->qp_vec);
1093         kfree(nt->mw_vec);
1094         kfree(nt);
1095 }
1096
1097 static void ntb_rx_copy_callback(void *data)
1098 {
1099         struct ntb_queue_entry *entry = data;
1100         struct ntb_transport_qp *qp = entry->qp;
1101         void *cb_data = entry->cb_data;
1102         unsigned int len = entry->len;
1103         struct ntb_payload_header *hdr = entry->rx_hdr;
1104
1105         hdr->flags = 0;
1106
1107         iowrite32(entry->index, &qp->rx_info->entry);
1108
1109         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1110
1111         if (qp->rx_handler && qp->client_ready)
1112                 qp->rx_handler(qp, qp->cb_data, cb_data, len);
1113 }
1114
1115 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1116 {
1117         void *buf = entry->buf;
1118         size_t len = entry->len;
1119
1120         memcpy(buf, offset, len);
1121
1122         /* Ensure that the data is fully copied out before clearing the flag */
1123         wmb();
1124
1125         ntb_rx_copy_callback(entry);
1126 }
1127
1128 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
1129                          size_t len)
1130 {
1131         struct dma_async_tx_descriptor *txd;
1132         struct ntb_transport_qp *qp = entry->qp;
1133         struct dma_chan *chan = qp->dma_chan;
1134         struct dma_device *device;
1135         size_t pay_off, buff_off;
1136         struct dmaengine_unmap_data *unmap;
1137         dma_cookie_t cookie;
1138         void *buf = entry->buf;
1139
1140         entry->len = len;
1141
1142         if (!chan)
1143                 goto err;
1144
1145         if (len < copy_bytes)
1146                 goto err_wait;
1147
1148         device = chan->device;
1149         pay_off = (size_t)offset & ~PAGE_MASK;
1150         buff_off = (size_t)buf & ~PAGE_MASK;
1151
1152         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1153                 goto err_wait;
1154
1155         unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1156         if (!unmap)
1157                 goto err_wait;
1158
1159         unmap->len = len;
1160         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1161                                       pay_off, len, DMA_TO_DEVICE);
1162         if (dma_mapping_error(device->dev, unmap->addr[0]))
1163                 goto err_get_unmap;
1164
1165         unmap->to_cnt = 1;
1166
1167         unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1168                                       buff_off, len, DMA_FROM_DEVICE);
1169         if (dma_mapping_error(device->dev, unmap->addr[1]))
1170                 goto err_get_unmap;
1171
1172         unmap->from_cnt = 1;
1173
1174         txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1175                                              unmap->addr[0], len,
1176                                              DMA_PREP_INTERRUPT);
1177         if (!txd)
1178                 goto err_get_unmap;
1179
1180         txd->callback = ntb_rx_copy_callback;
1181         txd->callback_param = entry;
1182         dma_set_unmap(txd, unmap);
1183
1184         cookie = dmaengine_submit(txd);
1185         if (dma_submit_error(cookie))
1186                 goto err_set_unmap;
1187
1188         dmaengine_unmap_put(unmap);
1189
1190         qp->last_cookie = cookie;
1191
1192         qp->rx_async++;
1193
1194         return;
1195
1196 err_set_unmap:
1197         dmaengine_unmap_put(unmap);
1198 err_get_unmap:
1199         dmaengine_unmap_put(unmap);
1200 err_wait:
1201         /* If the callbacks come out of order, the writing of the index to the
1202          * last completed will be out of order.  This may result in the
1203          * receive stalling forever.
1204          */
1205         dma_sync_wait(chan, qp->last_cookie);
1206 err:
1207         ntb_memcpy_rx(entry, offset);
1208         qp->rx_memcpy++;
1209 }
1210
1211 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1212 {
1213         struct ntb_payload_header *hdr;
1214         struct ntb_queue_entry *entry;
1215         void *offset;
1216         int rc;
1217
1218         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1219         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1220
1221         dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1222                 qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1223
1224         if (!(hdr->flags & DESC_DONE_FLAG)) {
1225                 dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1226                 qp->rx_ring_empty++;
1227                 return -EAGAIN;
1228         }
1229
1230         if (hdr->flags & LINK_DOWN_FLAG) {
1231                 dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1232                 ntb_qp_link_down(qp);
1233                 hdr->flags = 0;
1234                 return -EAGAIN;
1235         }
1236
1237         if (hdr->ver != (u32)qp->rx_pkts) {
1238                 dev_dbg(&qp->ndev->pdev->dev,
1239                         "version mismatch, expected %llu - got %u\n",
1240                         qp->rx_pkts, hdr->ver);
1241                 qp->rx_err_ver++;
1242                 return -EIO;
1243         }
1244
1245         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1246         if (!entry) {
1247                 dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1248                 qp->rx_err_no_buf++;
1249
1250                 rc = -ENOMEM;
1251                 goto err;
1252         }
1253
1254         if (hdr->len > entry->len) {
1255                 dev_dbg(&qp->ndev->pdev->dev,
1256                         "receive buffer overflow! Wanted %d got %d\n",
1257                         hdr->len, entry->len);
1258                 qp->rx_err_oflow++;
1259
1260                 rc = -EIO;
1261                 goto err;
1262         }
1263
1264         dev_dbg(&qp->ndev->pdev->dev,
1265                 "RX OK index %u ver %u size %d into buf size %d\n",
1266                 qp->rx_index, hdr->ver, hdr->len, entry->len);
1267
1268         qp->rx_bytes += hdr->len;
1269         qp->rx_pkts++;
1270
1271         entry->index = qp->rx_index;
1272         entry->rx_hdr = hdr;
1273
1274         ntb_async_rx(entry, offset, hdr->len);
1275
1276         qp->rx_index++;
1277         qp->rx_index %= qp->rx_max_entry;
1278
1279         return 0;
1280
1281 err:
1282         /* FIXME: if this syncrhonous update of the rx_index gets ahead of
1283          * asyncrhonous ntb_rx_copy_callback of previous entry, there are three
1284          * scenarios:
1285          *
1286          * 1) The peer might miss this update, but observe the update
1287          * from the memcpy completion callback.  In this case, the buffer will
1288          * not be freed on the peer to be reused for a different packet.  The
1289          * successful rx of a later packet would clear the condition, but the
1290          * condition could persist if several rx fail in a row.
1291          *
1292          * 2) The peer may observe this update before the asyncrhonous copy of
1293          * prior packets is completed.  The peer may overwrite the buffers of
1294          * the prior packets before they are copied.
1295          *
1296          * 3) Both: the peer may observe the update, and then observe the index
1297          * decrement by the asynchronous completion callback.  Who knows what
1298          * badness that will cause.
1299          */
1300         hdr->flags = 0;
1301         iowrite32(qp->rx_index, &qp->rx_info->entry);
1302
1303         return rc;
1304 }
1305
1306 static void ntb_transport_rxc_db(unsigned long data)
1307 {
1308         struct ntb_transport_qp *qp = (void *)data;
1309         int rc, i;
1310
1311         dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1312                 __func__, qp->qp_num);
1313
1314         /* Limit the number of packets processed in a single interrupt to
1315          * provide fairness to others
1316          */
1317         for (i = 0; i < qp->rx_max_entry; i++) {
1318                 rc = ntb_process_rxc(qp);
1319                 if (rc)
1320                         break;
1321         }
1322
1323         if (qp->dma_chan)
1324                 dma_async_issue_pending(qp->dma_chan);
1325
1326         if (i == qp->rx_max_entry) {
1327                 /* there is more work to do */
1328                 tasklet_schedule(&qp->rxc_db_work);
1329         } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1330                 /* the doorbell bit is set: clear it */
1331                 ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1332                 /* ntb_db_read ensures ntb_db_clear write is committed */
1333                 ntb_db_read(qp->ndev);
1334
1335                 /* an interrupt may have arrived between finishing
1336                  * ntb_process_rxc and clearing the doorbell bit:
1337                  * there might be some more work to do.
1338                  */
1339                 tasklet_schedule(&qp->rxc_db_work);
1340         }
1341 }
1342
1343 static void ntb_tx_copy_callback(void *data)
1344 {
1345         struct ntb_queue_entry *entry = data;
1346         struct ntb_transport_qp *qp = entry->qp;
1347         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1348
1349         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1350
1351         ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1352
1353         /* The entry length can only be zero if the packet is intended to be a
1354          * "link down" or similar.  Since no payload is being sent in these
1355          * cases, there is nothing to add to the completion queue.
1356          */
1357         if (entry->len > 0) {
1358                 qp->tx_bytes += entry->len;
1359
1360                 if (qp->tx_handler)
1361                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1362                                        entry->len);
1363         }
1364
1365         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1366 }
1367
1368 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1369 {
1370         memcpy_toio(offset, entry->buf, entry->len);
1371
1372         /* Ensure that the data is fully copied out before setting the flags */
1373         wmb();
1374
1375         ntb_tx_copy_callback(entry);
1376 }
1377
1378 static void ntb_async_tx(struct ntb_transport_qp *qp,
1379                          struct ntb_queue_entry *entry)
1380 {
1381         struct ntb_payload_header __iomem *hdr;
1382         struct dma_async_tx_descriptor *txd;
1383         struct dma_chan *chan = qp->dma_chan;
1384         struct dma_device *device;
1385         size_t dest_off, buff_off;
1386         struct dmaengine_unmap_data *unmap;
1387         dma_addr_t dest;
1388         dma_cookie_t cookie;
1389         void __iomem *offset;
1390         size_t len = entry->len;
1391         void *buf = entry->buf;
1392
1393         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1394         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1395         entry->tx_hdr = hdr;
1396
1397         iowrite32(entry->len, &hdr->len);
1398         iowrite32((u32)qp->tx_pkts, &hdr->ver);
1399
1400         if (!chan)
1401                 goto err;
1402
1403         if (len < copy_bytes)
1404                 goto err;
1405
1406         device = chan->device;
1407         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1408         buff_off = (size_t)buf & ~PAGE_MASK;
1409         dest_off = (size_t)dest & ~PAGE_MASK;
1410
1411         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1412                 goto err;
1413
1414         unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1415         if (!unmap)
1416                 goto err;
1417
1418         unmap->len = len;
1419         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1420                                       buff_off, len, DMA_TO_DEVICE);
1421         if (dma_mapping_error(device->dev, unmap->addr[0]))
1422                 goto err_get_unmap;
1423
1424         unmap->to_cnt = 1;
1425
1426         txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1427                                              DMA_PREP_INTERRUPT);
1428         if (!txd)
1429                 goto err_get_unmap;
1430
1431         txd->callback = ntb_tx_copy_callback;
1432         txd->callback_param = entry;
1433         dma_set_unmap(txd, unmap);
1434
1435         cookie = dmaengine_submit(txd);
1436         if (dma_submit_error(cookie))
1437                 goto err_set_unmap;
1438
1439         dmaengine_unmap_put(unmap);
1440
1441         dma_async_issue_pending(chan);
1442         qp->tx_async++;
1443
1444         return;
1445 err_set_unmap:
1446         dmaengine_unmap_put(unmap);
1447 err_get_unmap:
1448         dmaengine_unmap_put(unmap);
1449 err:
1450         ntb_memcpy_tx(entry, offset);
1451         qp->tx_memcpy++;
1452 }
1453
1454 static int ntb_process_tx(struct ntb_transport_qp *qp,
1455                           struct ntb_queue_entry *entry)
1456 {
1457         if (qp->tx_index == qp->remote_rx_info->entry) {
1458                 qp->tx_ring_full++;
1459                 return -EAGAIN;
1460         }
1461
1462         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1463                 if (qp->tx_handler)
1464                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1465
1466                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1467                              &qp->tx_free_q);
1468                 return 0;
1469         }
1470
1471         ntb_async_tx(qp, entry);
1472
1473         qp->tx_index++;
1474         qp->tx_index %= qp->tx_max_entry;
1475
1476         qp->tx_pkts++;
1477
1478         return 0;
1479 }
1480
1481 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1482 {
1483         struct pci_dev *pdev = qp->ndev->pdev;
1484         struct ntb_queue_entry *entry;
1485         int i, rc;
1486
1487         if (!qp->link_is_up)
1488                 return;
1489
1490         dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1491
1492         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1493                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1494                 if (entry)
1495                         break;
1496                 msleep(100);
1497         }
1498
1499         if (!entry)
1500                 return;
1501
1502         entry->cb_data = NULL;
1503         entry->buf = NULL;
1504         entry->len = 0;
1505         entry->flags = LINK_DOWN_FLAG;
1506
1507         rc = ntb_process_tx(qp, entry);
1508         if (rc)
1509                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1510                         qp->qp_num);
1511
1512         ntb_qp_link_down_reset(qp);
1513 }
1514
1515 /**
1516  * ntb_transport_create_queue - Create a new NTB transport layer queue
1517  * @rx_handler: receive callback function
1518  * @tx_handler: transmit callback function
1519  * @event_handler: event callback function
1520  *
1521  * Create a new NTB transport layer queue and provide the queue with a callback
1522  * routine for both transmit and receive.  The receive callback routine will be
1523  * used to pass up data when the transport has received it on the queue.   The
1524  * transmit callback routine will be called when the transport has completed the
1525  * transmission of the data on the queue and the data is ready to be freed.
1526  *
1527  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1528  */
1529 struct ntb_transport_qp *
1530 ntb_transport_create_queue(void *data, struct device *client_dev,
1531                            const struct ntb_queue_handlers *handlers)
1532 {
1533         struct ntb_dev *ndev;
1534         struct pci_dev *pdev;
1535         struct ntb_transport_ctx *nt;
1536         struct ntb_queue_entry *entry;
1537         struct ntb_transport_qp *qp;
1538         u64 qp_bit;
1539         unsigned int free_queue;
1540         int i;
1541
1542         ndev = dev_ntb(client_dev->parent);
1543         pdev = ndev->pdev;
1544         nt = ndev->ctx;
1545
1546         free_queue = ffs(nt->qp_bitmap);
1547         if (!free_queue)
1548                 goto err;
1549
1550         /* decrement free_queue to make it zero based */
1551         free_queue--;
1552
1553         qp = &nt->qp_vec[free_queue];
1554         qp_bit = BIT_ULL(qp->qp_num);
1555
1556         nt->qp_bitmap_free &= ~qp_bit;
1557
1558         qp->cb_data = data;
1559         qp->rx_handler = handlers->rx_handler;
1560         qp->tx_handler = handlers->tx_handler;
1561         qp->event_handler = handlers->event_handler;
1562
1563         dmaengine_get();
1564         qp->dma_chan = dma_find_channel(DMA_MEMCPY);
1565         if (!qp->dma_chan) {
1566                 dmaengine_put();
1567                 dev_info(&pdev->dev, "Unable to allocate DMA channel, using CPU instead\n");
1568         }
1569
1570         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1571                 entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
1572                 if (!entry)
1573                         goto err1;
1574
1575                 entry->qp = qp;
1576                 ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1577                              &qp->rx_free_q);
1578         }
1579
1580         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1581                 entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
1582                 if (!entry)
1583                         goto err2;
1584
1585                 entry->qp = qp;
1586                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1587                              &qp->tx_free_q);
1588         }
1589
1590         ntb_db_clear(qp->ndev, qp_bit);
1591         ntb_db_clear_mask(qp->ndev, qp_bit);
1592
1593         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1594
1595         return qp;
1596
1597 err2:
1598         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1599                 kfree(entry);
1600 err1:
1601         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1602                 kfree(entry);
1603         if (qp->dma_chan)
1604                 dmaengine_put();
1605         nt->qp_bitmap_free |= qp_bit;
1606 err:
1607         return NULL;
1608 }
1609 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1610
1611 /**
1612  * ntb_transport_free_queue - Frees NTB transport queue
1613  * @qp: NTB queue to be freed
1614  *
1615  * Frees NTB transport queue
1616  */
1617 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1618 {
1619         struct ntb_transport_ctx *nt = qp->transport;
1620         struct pci_dev *pdev;
1621         struct ntb_queue_entry *entry;
1622         u64 qp_bit;
1623
1624         if (!qp)
1625                 return;
1626
1627         pdev = qp->ndev->pdev;
1628
1629         if (qp->dma_chan) {
1630                 struct dma_chan *chan = qp->dma_chan;
1631                 /* Putting the dma_chan to NULL will force any new traffic to be
1632                  * processed by the CPU instead of the DAM engine
1633                  */
1634                 qp->dma_chan = NULL;
1635
1636                 /* Try to be nice and wait for any queued DMA engine
1637                  * transactions to process before smashing it with a rock
1638                  */
1639                 dma_sync_wait(chan, qp->last_cookie);
1640                 dmaengine_terminate_all(chan);
1641                 dmaengine_put();
1642         }
1643
1644         qp_bit = BIT_ULL(qp->qp_num);
1645
1646         ntb_db_set_mask(qp->ndev, qp_bit);
1647         tasklet_disable(&qp->rxc_db_work);
1648
1649         cancel_delayed_work_sync(&qp->link_work);
1650
1651         qp->cb_data = NULL;
1652         qp->rx_handler = NULL;
1653         qp->tx_handler = NULL;
1654         qp->event_handler = NULL;
1655
1656         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1657                 kfree(entry);
1658
1659         while ((entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
1660                 dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
1661                 kfree(entry);
1662         }
1663
1664         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1665                 kfree(entry);
1666
1667         nt->qp_bitmap_free |= qp_bit;
1668
1669         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1670 }
1671 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1672
1673 /**
1674  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1675  * @qp: NTB queue to be freed
1676  * @len: pointer to variable to write enqueued buffers length
1677  *
1678  * Dequeues unused buffers from receive queue.  Should only be used during
1679  * shutdown of qp.
1680  *
1681  * RETURNS: NULL error value on error, or void* for success.
1682  */
1683 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1684 {
1685         struct ntb_queue_entry *entry;
1686         void *buf;
1687
1688         if (!qp || qp->client_ready)
1689                 return NULL;
1690
1691         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1692         if (!entry)
1693                 return NULL;
1694
1695         buf = entry->cb_data;
1696         *len = entry->len;
1697
1698         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1699
1700         return buf;
1701 }
1702 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1703
1704 /**
1705  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1706  * @qp: NTB transport layer queue the entry is to be enqueued on
1707  * @cb: per buffer pointer for callback function to use
1708  * @data: pointer to data buffer that incoming packets will be copied into
1709  * @len: length of the data buffer
1710  *
1711  * Enqueue a new receive buffer onto the transport queue into which a NTB
1712  * payload can be received into.
1713  *
1714  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1715  */
1716 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1717                              unsigned int len)
1718 {
1719         struct ntb_queue_entry *entry;
1720
1721         if (!qp)
1722                 return -EINVAL;
1723
1724         entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
1725         if (!entry)
1726                 return -ENOMEM;
1727
1728         entry->cb_data = cb;
1729         entry->buf = data;
1730         entry->len = len;
1731
1732         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
1733
1734         return 0;
1735 }
1736 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1737
1738 /**
1739  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1740  * @qp: NTB transport layer queue the entry is to be enqueued on
1741  * @cb: per buffer pointer for callback function to use
1742  * @data: pointer to data buffer that will be sent
1743  * @len: length of the data buffer
1744  *
1745  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1746  * payload will be transmitted.  This assumes that a lock is being held to
1747  * serialize access to the qp.
1748  *
1749  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1750  */
1751 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1752                              unsigned int len)
1753 {
1754         struct ntb_queue_entry *entry;
1755         int rc;
1756
1757         if (!qp || !qp->link_is_up || !len)
1758                 return -EINVAL;
1759
1760         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1761         if (!entry) {
1762                 qp->tx_err_no_buf++;
1763                 return -ENOMEM;
1764         }
1765
1766         entry->cb_data = cb;
1767         entry->buf = data;
1768         entry->len = len;
1769         entry->flags = 0;
1770
1771         rc = ntb_process_tx(qp, entry);
1772         if (rc)
1773                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1774                              &qp->tx_free_q);
1775
1776         return rc;
1777 }
1778 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1779
1780 /**
1781  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1782  * @qp: NTB transport layer queue to be enabled
1783  *
1784  * Notify NTB transport layer of client readiness to use queue
1785  */
1786 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1787 {
1788         if (!qp)
1789                 return;
1790
1791         qp->client_ready = true;
1792
1793         if (qp->transport->link_is_up)
1794                 schedule_delayed_work(&qp->link_work, 0);
1795 }
1796 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1797
1798 /**
1799  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1800  * @qp: NTB transport layer queue to be disabled
1801  *
1802  * Notify NTB transport layer of client's desire to no longer receive data on
1803  * transport queue specified.  It is the client's responsibility to ensure all
1804  * entries on queue are purged or otherwise handled appropriately.
1805  */
1806 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1807 {
1808         struct pci_dev *pdev;
1809         int val;
1810
1811         if (!qp)
1812                 return;
1813
1814         pdev = qp->ndev->pdev;
1815         qp->client_ready = false;
1816
1817         val = ntb_spad_read(qp->ndev, QP_LINKS);
1818
1819         ntb_peer_spad_write(qp->ndev, QP_LINKS,
1820                             val & ~BIT(qp->qp_num));
1821
1822         if (qp->link_is_up)
1823                 ntb_send_link_down(qp);
1824         else
1825                 cancel_delayed_work_sync(&qp->link_work);
1826 }
1827 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1828
1829 /**
1830  * ntb_transport_link_query - Query transport link state
1831  * @qp: NTB transport layer queue to be queried
1832  *
1833  * Query connectivity to the remote system of the NTB transport queue
1834  *
1835  * RETURNS: true for link up or false for link down
1836  */
1837 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1838 {
1839         if (!qp)
1840                 return false;
1841
1842         return qp->link_is_up;
1843 }
1844 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1845
1846 /**
1847  * ntb_transport_qp_num - Query the qp number
1848  * @qp: NTB transport layer queue to be queried
1849  *
1850  * Query qp number of the NTB transport queue
1851  *
1852  * RETURNS: a zero based number specifying the qp number
1853  */
1854 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1855 {
1856         if (!qp)
1857                 return 0;
1858
1859         return qp->qp_num;
1860 }
1861 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1862
1863 /**
1864  * ntb_transport_max_size - Query the max payload size of a qp
1865  * @qp: NTB transport layer queue to be queried
1866  *
1867  * Query the maximum payload size permissible on the given qp
1868  *
1869  * RETURNS: the max payload size of a qp
1870  */
1871 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1872 {
1873         unsigned int max;
1874
1875         if (!qp)
1876                 return 0;
1877
1878         if (!qp->dma_chan)
1879                 return qp->tx_max_frame - sizeof(struct ntb_payload_header);
1880
1881         /* If DMA engine usage is possible, try to find the max size for that */
1882         max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
1883         max -= max % (1 << qp->dma_chan->device->copy_align);
1884
1885         return max;
1886 }
1887 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
1888
1889 static void ntb_transport_doorbell_callback(void *data, int vector)
1890 {
1891         struct ntb_transport_ctx *nt = data;
1892         struct ntb_transport_qp *qp;
1893         u64 db_bits;
1894         unsigned int qp_num;
1895
1896         db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
1897                    ntb_db_vector_mask(nt->ndev, vector));
1898
1899         while (db_bits) {
1900                 qp_num = __ffs(db_bits);
1901                 qp = &nt->qp_vec[qp_num];
1902
1903                 tasklet_schedule(&qp->rxc_db_work);
1904
1905                 db_bits &= ~BIT_ULL(qp_num);
1906         }
1907 }
1908
1909 static const struct ntb_ctx_ops ntb_transport_ops = {
1910         .link_event = ntb_transport_event_callback,
1911         .db_event = ntb_transport_doorbell_callback,
1912 };
1913
1914 static struct ntb_client ntb_transport_client = {
1915         .ops = {
1916                 .probe = ntb_transport_probe,
1917                 .remove = ntb_transport_free,
1918         },
1919 };
1920
1921 static int __init ntb_transport_init(void)
1922 {
1923         int rc;
1924
1925         if (debugfs_initialized())
1926                 nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
1927
1928         rc = bus_register(&ntb_transport_bus);
1929         if (rc)
1930                 goto err_bus;
1931
1932         rc = ntb_register_client(&ntb_transport_client);
1933         if (rc)
1934                 goto err_client;
1935
1936         return 0;
1937
1938 err_client:
1939         bus_unregister(&ntb_transport_bus);
1940 err_bus:
1941         debugfs_remove_recursive(nt_debugfs_dir);
1942         return rc;
1943 }
1944 module_init(ntb_transport_init);
1945
1946 static void __exit ntb_transport_exit(void)
1947 {
1948         debugfs_remove_recursive(nt_debugfs_dir);
1949
1950         ntb_unregister_client(&ntb_transport_client);
1951         bus_unregister(&ntb_transport_bus);
1952 }
1953 module_exit(ntb_transport_exit);