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