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