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  *
   9  *   This program is free software; you can redistribute it and/or modify
  10  *   it under the terms of version 2 of the GNU General Public License as
  11  *   published by the Free Software Foundation.
  12  *
  13  *   BSD LICENSE
  14  *
  15  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
  16  *
  17  *   Redistribution and use in source and binary forms, with or without
  18  *   modification, are permitted provided that the following conditions
  19  *   are met:
  20  *
  21  *     * Redistributions of source code must retain the above copyright
  22  *       notice, this list of conditions and the following disclaimer.
  23  *     * Redistributions in binary form must reproduce the above copy
  24  *       notice, this list of conditions and the following disclaimer in
  25  *       the documentation and/or other materials provided with the
  26  *       distribution.
  27  *     * Neither the name of Intel Corporation nor the names of its
  28  *       contributors may be used to endorse or promote products derived
  29  *       from this software without specific prior written permission.
  30  *
  31  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  34  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  36  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  37  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  38  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  39  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  41  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  42  *
  43  * Intel PCIe NTB Linux driver
  44  *
  45  * Contact Information:
  46  * Jon Mason <jon.mason@intel.com>
  47  */
  48 #include <linux/debugfs.h>
  49 #include <linux/delay.h>
  50 #include <linux/dma-mapping.h>
  51 #include <linux/errno.h>
  52 #include <linux/export.h>
  53 #include <linux/interrupt.h>
  54 #include <linux/module.h>
  55 #include <linux/pci.h>
  56 #include <linux/slab.h>
  57 #include <linux/types.h>
  58 #include <linux/ntb.h>
  59 #include "ntb_hw.h"
  60
  61 #define NTB_TRANSPORT_VERSION   1
  62
  63 static int transport_mtu = 0x401E;
  64 module_param(transport_mtu, uint, 0644);
  65 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
  66
  67 static unsigned char max_num_clients = 2;
  68 module_param(max_num_clients, byte, 0644);
  69 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
  70
  71 struct ntb_queue_entry {
  72         /* ntb_queue list reference */
  73         struct list_head entry;
  74         /* pointers to data to be transfered */
  75         void *cb_data;
  76         void *buf;
  77         unsigned int len;
  78         unsigned int flags;
  79 };
  80
  81 struct ntb_transport_qp {
  82         struct ntb_transport *transport;
  83         struct ntb_device *ndev;
  84         void *cb_data;
  85
  86         bool client_ready;
  87         bool qp_link;
  88         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
  89
  90         void (*tx_handler) (struct ntb_transport_qp *qp, void *qp_data,
  91                             void *data, int len);
  92         struct list_head tx_free_q;
  93         spinlock_t ntb_tx_free_q_lock;
  94         void *tx_mw_begin;
  95         void *tx_mw_end;
  96         void *tx_offset;
  97
  98         void (*rx_handler) (struct ntb_transport_qp *qp, void *qp_data,
  99                             void *data, int len);
 100         struct tasklet_struct rx_work;
 101         struct list_head rx_pend_q;
 102         struct list_head rx_free_q;
 103         spinlock_t ntb_rx_pend_q_lock;
 104         spinlock_t ntb_rx_free_q_lock;
 105         void *rx_buff_begin;
 106         void *rx_buff_end;
 107         void *rx_offset;
 108
 109         void (*event_handler) (void *data, int status);
 110         struct delayed_work link_work;
 111
 112         struct dentry *debugfs_dir;
 113         struct dentry *debugfs_stats;
 114
 115         /* Stats */
 116         u64 rx_bytes;
 117         u64 rx_pkts;
 118         u64 rx_ring_empty;
 119         u64 rx_err_no_buf;
 120         u64 rx_err_oflow;
 121         u64 rx_err_ver;
 122         u64 tx_bytes;
 123         u64 tx_pkts;
 124         u64 tx_ring_full;
 125 };
 126
 127 struct ntb_transport_mw {
 128         size_t size;
 129         void *virt_addr;
 130         dma_addr_t dma_addr;
 131 };
 132
 133 struct ntb_transport_client_dev {
 134         struct list_head entry;
 135         struct device dev;
 136 };
 137
 138 struct ntb_transport {
 139         struct list_head entry;
 140         struct list_head client_devs;
 141
 142         struct ntb_device *ndev;
 143         struct ntb_transport_mw mw[NTB_NUM_MW];
 144         struct ntb_transport_qp *qps;
 145         unsigned int max_qps;
 146         unsigned long qp_bitmap;
 147         bool transport_link;
 148         struct delayed_work link_work;
 149         struct dentry *debugfs_dir;
 150 };
 151
 152 enum {
 153         DESC_DONE_FLAG = 1 << 0,
 154         LINK_DOWN_FLAG = 1 << 1,
 155 };
 156
 157 struct ntb_payload_header {
 158         u64 ver;
 159         unsigned int len;
 160         unsigned int flags;
 161 };
 162
 163 enum {
 164         VERSION = 0,
 165         MW0_SZ,
 166         MW1_SZ,
 167         NUM_QPS,
 168         QP_LINKS,
 169         MAX_SPAD,
 170 };
 171
 172 #define QP_TO_MW(qp)            ((qp) % NTB_NUM_MW)
 173 #define NTB_QP_DEF_NUM_ENTRIES  100
 174 #define NTB_LINK_DOWN_TIMEOUT   10
 175
 176 static int ntb_match_bus(struct device *dev, struct device_driver *drv)
 177 {
 178         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 179 }
 180
 181 static int ntb_client_probe(struct device *dev)
 182 {
 183         const struct ntb_client *drv = container_of(dev->driver,
 184                                                     struct ntb_client, driver);
 185         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 186         int rc = -EINVAL;
 187
 188         get_device(dev);
 189         if (drv && drv->probe)
 190                 rc = drv->probe(pdev);
 191         if (rc)
 192                 put_device(dev);
 193
 194         return rc;
 195 }
 196
 197 static int ntb_client_remove(struct device *dev)
 198 {
 199         const struct ntb_client *drv = container_of(dev->driver,
 200                                                     struct ntb_client, driver);
 201         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 202
 203         if (drv && drv->remove)
 204                 drv->remove(pdev);
 205
 206         put_device(dev);
 207
 208         return 0;
 209 }
 210
 211 struct bus_type ntb_bus_type = {
 212         .name = "ntb_bus",
 213         .match = ntb_match_bus,
 214         .probe = ntb_client_probe,
 215         .remove = ntb_client_remove,
 216 };
 217
 218 static LIST_HEAD(ntb_transport_list);
 219
 220 static int ntb_bus_init(struct ntb_transport *nt)
 221 {
 222         if (list_empty(&ntb_transport_list)) {
 223                 int rc = bus_register(&ntb_bus_type);
 224                 if (rc)
 225                         return rc;
 226         }
 227
 228         list_add(&nt->entry, &ntb_transport_list);
 229
 230         return 0;
 231 }
 232
 233 static void ntb_bus_remove(struct ntb_transport *nt)
 234 {
 235         struct ntb_transport_client_dev *client_dev, *cd;
 236
 237         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 238                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 239                         dev_name(&client_dev->dev));
 240                 list_del(&client_dev->entry);
 241                 device_unregister(&client_dev->dev);
 242         }
 243
 244         list_del(&nt->entry);
 245
 246         if (list_empty(&ntb_transport_list))
 247                 bus_unregister(&ntb_bus_type);
 248 }
 249
 250 static void ntb_client_release(struct device *dev)
 251 {
 252         struct ntb_transport_client_dev *client_dev;
 253         client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
 254
 255         kfree(client_dev);
 256 }
 257
 258 /**
 259  * ntb_unregister_client_dev - Unregister NTB client device
 260  * @device_name: Name of NTB client device
 261  *
 262  * Unregister an NTB client device with the NTB transport layer
 263  */
 264 void ntb_unregister_client_dev(char *device_name)
 265 {
 266         struct ntb_transport_client_dev *client, *cd;
 267         struct ntb_transport *nt;
 268
 269         list_for_each_entry(nt, &ntb_transport_list, entry)
 270                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 271                         if (!strncmp(dev_name(&client->dev), device_name,
 272                                      strlen(device_name))) {
 273                                 list_del(&client->entry);
 274                                 device_unregister(&client->dev);
 275                         }
 276 }
 277 EXPORT_SYMBOL_GPL(ntb_unregister_client_dev);
 278
 279 /**
 280  * ntb_register_client_dev - Register NTB client device
 281  * @device_name: Name of NTB client device
 282  *
 283  * Register an NTB client device with the NTB transport layer
 284  */
 285 int ntb_register_client_dev(char *device_name)
 286 {
 287         struct ntb_transport_client_dev *client_dev;
 288         struct ntb_transport *nt;
 289         int rc;
 290
 291         if (list_empty(&ntb_transport_list))
 292                 return -ENODEV;
 293
 294         list_for_each_entry(nt, &ntb_transport_list, entry) {
 295                 struct device *dev;
 296
 297                 client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
 298                                      GFP_KERNEL);
 299                 if (!client_dev) {
 300                         rc = -ENOMEM;
 301                         goto err;
 302                 }
 303
 304                 dev = &client_dev->dev;
 305
 306                 /* setup and register client devices */
 307                 dev_set_name(dev, "%s", device_name);
 308                 dev->bus = &ntb_bus_type;
 309                 dev->release = ntb_client_release;
 310                 dev->parent = &ntb_query_pdev(nt->ndev)->dev;
 311
 312                 rc = device_register(dev);
 313                 if (rc) {
 314                         kfree(client_dev);
 315                         goto err;
 316                 }
 317
 318                 list_add_tail(&client_dev->entry, &nt->client_devs);
 319         }
 320
 321         return 0;
 322
 323 err:
 324         ntb_unregister_client_dev(device_name);
 325
 326         return rc;
 327 }
 328 EXPORT_SYMBOL_GPL(ntb_register_client_dev);
 329
 330 /**
 331  * ntb_register_client - Register NTB client driver
 332  * @drv: NTB client driver to be registered
 333  *
 334  * Register an NTB client driver with the NTB transport layer
 335  *
 336  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 337  */
 338 int ntb_register_client(struct ntb_client *drv)
 339 {
 340         drv->driver.bus = &ntb_bus_type;
 341
 342         if (list_empty(&ntb_transport_list))
 343                 return -ENODEV;
 344
 345         return driver_register(&drv->driver);
 346 }
 347 EXPORT_SYMBOL_GPL(ntb_register_client);
 348
 349 /**
 350  * ntb_unregister_client - Unregister NTB client driver
 351  * @drv: NTB client driver to be unregistered
 352  *
 353  * Unregister an NTB client driver with the NTB transport layer
 354  *
 355  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 356  */
 357 void ntb_unregister_client(struct ntb_client *drv)
 358 {
 359         driver_unregister(&drv->driver);
 360 }
 361 EXPORT_SYMBOL_GPL(ntb_unregister_client);
 362
 363 static int debugfs_open(struct inode *inode, struct file *filp)
 364 {
 365         filp->private_data = inode->i_private;
 366         return 0;
 367 }
 368
 369 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 370                             loff_t *offp)
 371 {
 372         struct ntb_transport_qp *qp;
 373         char buf[1024];
 374         ssize_t ret, out_offset, out_count;
 375
 376         out_count = 1024;
 377
 378         qp = filp->private_data;
 379         out_offset = 0;
 380         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 381                                "NTB QP stats\n");
 382         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 383                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 384         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 385                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 386         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 387                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 388         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 389                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 390         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 391                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 392         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 393                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 394         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 395                                "rx_buff_begin - %p\n", qp->rx_buff_begin);
 396         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 397                                "rx_offset - \t%p\n", qp->rx_offset);
 398         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 399                                "rx_buff_end - \t%p\n", qp->rx_buff_end);
 400
 401         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 402                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 403         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 404                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 405         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 406                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 407         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 408                                "tx_mw_begin - \t%p\n", qp->tx_mw_begin);
 409         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 410                                "tx_offset - \t%p\n", qp->tx_offset);
 411         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 412                                "tx_mw_end - \t%p\n", qp->tx_mw_end);
 413
 414         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 415                                "QP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
 416                                "Up" : "Down");
 417
 418         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 419         return ret;
 420 }
 421
 422 static const struct file_operations ntb_qp_debugfs_stats = {
 423         .owner = THIS_MODULE,
 424         .open = debugfs_open,
 425         .read = debugfs_read,
 426 };
 427
 428 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 429                          struct list_head *list)
 430 {
 431         unsigned long flags;
 432
 433         spin_lock_irqsave(lock, flags);
 434         list_add_tail(entry, list);
 435         spin_unlock_irqrestore(lock, flags);
 436 }
 437
 438 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 439                                                 struct list_head *list)
 440 {
 441         struct ntb_queue_entry *entry;
 442         unsigned long flags;
 443
 444         spin_lock_irqsave(lock, flags);
 445         if (list_empty(list)) {
 446                 entry = NULL;
 447                 goto out;
 448         }
 449         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 450         list_del(&entry->entry);
 451 out:
 452         spin_unlock_irqrestore(lock, flags);
 453
 454         return entry;
 455 }
 456
 457 static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
 458                                       unsigned int qp_num)
 459 {
 460         struct ntb_transport_qp *qp = &nt->qps[qp_num];
 461         unsigned int size, num_qps_mw;
 462         u8 mw_num = QP_TO_MW(qp_num);
 463
 464         WARN_ON(nt->mw[mw_num].virt_addr == 0);
 465
 466         if (nt->max_qps % NTB_NUM_MW && !mw_num)
 467                 num_qps_mw = nt->max_qps / NTB_NUM_MW +
 468                              (nt->max_qps % NTB_NUM_MW - mw_num);
 469         else
 470                 num_qps_mw = nt->max_qps / NTB_NUM_MW;
 471
 472         size = nt->mw[mw_num].size / num_qps_mw;
 473
 474         qp->rx_buff_begin = nt->mw[mw_num].virt_addr +
 475                             (qp_num / NTB_NUM_MW * size);
 476         qp->rx_buff_end = qp->rx_buff_begin + size;
 477         qp->rx_offset = qp->rx_buff_begin;
 478
 479         qp->tx_mw_begin = ntb_get_mw_vbase(nt->ndev, mw_num) +
 480                           (qp_num / NTB_NUM_MW * size);
 481         qp->tx_mw_end = qp->tx_mw_begin + size;
 482         qp->tx_offset = qp->tx_mw_begin;
 483
 484         qp->rx_pkts = 0;
 485         qp->tx_pkts = 0;
 486 }
 487
 488 static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
 489 {
 490         struct ntb_transport_mw *mw = &nt->mw[num_mw];
 491         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 492         void *offset;
 493
 494         /* Alloc memory for receiving data.  Must be 4k aligned */
 495         mw->size = ALIGN(size, 4096);
 496
 497         mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
 498                                            GFP_KERNEL);
 499         if (!mw->virt_addr) {
 500                 dev_err(&pdev->dev, "Unable to allocate MW buffer of size %d\n",
 501                        (int) mw->size);
 502                 return -ENOMEM;
 503         }
 504
 505         /* setup the hdr offsets with 0's */
 506         for (offset = mw->virt_addr + transport_mtu -
 507                       sizeof(struct ntb_payload_header);
 508              offset < mw->virt_addr + size; offset += transport_mtu)
 509                 memset(offset, 0, sizeof(struct ntb_payload_header));
 510
 511         /* Notify HW the memory location of the receive buffer */
 512         ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
 513
 514         return 0;
 515 }
 516
 517 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 518 {
 519         struct ntb_transport *nt = qp->transport;
 520         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 521
 522         if (qp->qp_link == NTB_LINK_DOWN) {
 523                 cancel_delayed_work_sync(&qp->link_work);
 524                 return;
 525         }
 526
 527         if (qp->event_handler)
 528                 qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
 529
 530         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
 531         qp->qp_link = NTB_LINK_DOWN;
 532
 533         if (nt->transport_link == NTB_LINK_UP)
 534                 schedule_delayed_work(&qp->link_work,
 535                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 536 }
 537
 538 static void ntb_transport_conn_down(struct ntb_transport *nt)
 539 {
 540         int i;
 541
 542         if (nt->transport_link == NTB_LINK_DOWN)
 543                 cancel_delayed_work_sync(&nt->link_work);
 544         else
 545                 nt->transport_link = NTB_LINK_DOWN;
 546
 547         /* Pass along the info to any clients */
 548         for (i = 0; i < nt->max_qps; i++)
 549                 if (!test_bit(i, &nt->qp_bitmap))
 550                         ntb_qp_link_down(&nt->qps[i]);
 551
 552         /* The scratchpad registers keep the values if the remote side
 553          * goes down, blast them now to give them a sane value the next
 554          * time they are accessed
 555          */
 556         for (i = 0; i < MAX_SPAD; i++)
 557                 ntb_write_local_spad(nt->ndev, i, 0);
 558 }
 559
 560 static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
 561 {
 562         struct ntb_transport *nt = data;
 563
 564         switch (event) {
 565         case NTB_EVENT_HW_LINK_UP:
 566                 schedule_delayed_work(&nt->link_work, 0);
 567                 break;
 568         case NTB_EVENT_HW_LINK_DOWN:
 569                 ntb_transport_conn_down(nt);
 570                 break;
 571         default:
 572                 BUG();
 573         }
 574 }
 575
 576 static void ntb_transport_link_work(struct work_struct *work)
 577 {
 578         struct ntb_transport *nt = container_of(work, struct ntb_transport,
 579                                                 link_work.work);
 580         struct ntb_device *ndev = nt->ndev;
 581         struct pci_dev *pdev = ntb_query_pdev(ndev);
 582         u32 val;
 583         int rc, i;
 584
 585         /* send the local info */
 586         rc = ntb_write_remote_spad(ndev, VERSION, NTB_TRANSPORT_VERSION);
 587         if (rc) {
 588                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 589                         0, VERSION);
 590                 goto out;
 591         }
 592
 593         rc = ntb_write_remote_spad(ndev, MW0_SZ, ntb_get_mw_size(ndev, 0));
 594         if (rc) {
 595                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 596                         (u32) ntb_get_mw_size(ndev, 0), MW0_SZ);
 597                 goto out;
 598         }
 599
 600         rc = ntb_write_remote_spad(ndev, MW1_SZ, ntb_get_mw_size(ndev, 1));
 601         if (rc) {
 602                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 603                         (u32) ntb_get_mw_size(ndev, 1), MW1_SZ);
 604                 goto out;
 605         }
 606
 607         rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
 608         if (rc) {
 609                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 610                         nt->max_qps, NUM_QPS);
 611                 goto out;
 612         }
 613
 614         rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
 615         if (rc) {
 616                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
 617                 goto out;
 618         }
 619
 620         rc = ntb_write_remote_spad(ndev, QP_LINKS, val);
 621         if (rc) {
 622                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 623                         val, QP_LINKS);
 624                 goto out;
 625         }
 626
 627         /* Query the remote side for its info */
 628         rc = ntb_read_remote_spad(ndev, VERSION, &val);
 629         if (rc) {
 630                 dev_err(&pdev->dev, "Error reading remote spad %d\n", VERSION);
 631                 goto out;
 632         }
 633
 634         if (val != NTB_TRANSPORT_VERSION)
 635                 goto out;
 636         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 637
 638         rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
 639         if (rc) {
 640                 dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
 641                 goto out;
 642         }
 643
 644         if (val != nt->max_qps)
 645                 goto out;
 646         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 647
 648         rc = ntb_read_remote_spad(ndev, MW0_SZ, &val);
 649         if (rc) {
 650                 dev_err(&pdev->dev, "Error reading remote spad %d\n", MW0_SZ);
 651                 goto out;
 652         }
 653
 654         if (!val)
 655                 goto out;
 656         dev_dbg(&pdev->dev, "Remote MW0 size = %d\n", val);
 657
 658         rc = ntb_set_mw(nt, 0, val);
 659         if (rc)
 660                 goto out;
 661
 662         rc = ntb_read_remote_spad(ndev, MW1_SZ, &val);
 663         if (rc) {
 664                 dev_err(&pdev->dev, "Error reading remote spad %d\n", MW1_SZ);
 665                 goto out;
 666         }
 667
 668         if (!val)
 669                 goto out;
 670         dev_dbg(&pdev->dev, "Remote MW1 size = %d\n", val);
 671
 672         rc = ntb_set_mw(nt, 1, val);
 673         if (rc)
 674                 goto out;
 675
 676         nt->transport_link = NTB_LINK_UP;
 677
 678         for (i = 0; i < nt->max_qps; i++) {
 679                 struct ntb_transport_qp *qp = &nt->qps[i];
 680
 681                 ntb_transport_setup_qp_mw(nt, i);
 682
 683                 if (qp->client_ready == NTB_LINK_UP)
 684                         schedule_delayed_work(&qp->link_work, 0);
 685         }
 686
 687         return;
 688
 689 out:
 690         if (ntb_hw_link_status(ndev))
 691                 schedule_delayed_work(&nt->link_work,
 692                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 693 }
 694
 695 static void ntb_qp_link_work(struct work_struct *work)
 696 {
 697         struct ntb_transport_qp *qp = container_of(work,
 698                                                    struct ntb_transport_qp,
 699                                                    link_work.work);
 700         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
 701         struct ntb_transport *nt = qp->transport;
 702         int rc, val;
 703
 704         WARN_ON(nt->transport_link != NTB_LINK_UP);
 705
 706         rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
 707         if (rc) {
 708                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
 709                 return;
 710         }
 711
 712         rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
 713         if (rc)
 714                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 715                         val | 1 << qp->qp_num, QP_LINKS);
 716
 717         /* query remote spad for qp ready bits */
 718         rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
 719         if (rc)
 720                 dev_err(&pdev->dev, "Error reading remote spad %d\n", QP_LINKS);
 721
 722         dev_dbg(&pdev->dev, "Remote QP link status = %x\n", val);
 723
 724         /* See if the remote side is up */
 725         if (1 << qp->qp_num & val) {
 726                 qp->qp_link = NTB_LINK_UP;
 727
 728                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 729                 if (qp->event_handler)
 730                         qp->event_handler(qp->cb_data, NTB_LINK_UP);
 731         } else if (nt->transport_link == NTB_LINK_UP)
 732                 schedule_delayed_work(&qp->link_work,
 733                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 734 }
 735
 736 static void ntb_transport_init_queue(struct ntb_transport *nt,
 737                                      unsigned int qp_num)
 738 {
 739         struct ntb_transport_qp *qp;
 740
 741         qp = &nt->qps[qp_num];
 742         qp->qp_num = qp_num;
 743         qp->transport = nt;
 744         qp->ndev = nt->ndev;
 745         qp->qp_link = NTB_LINK_DOWN;
 746         qp->client_ready = NTB_LINK_DOWN;
 747         qp->event_handler = NULL;
 748
 749         if (nt->debugfs_dir) {
 750                 char debugfs_name[4];
 751
 752                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 753                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 754                                                      nt->debugfs_dir);
 755
 756                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 757                                                         qp->debugfs_dir, qp,
 758                                                         &ntb_qp_debugfs_stats);
 759         }
 760
 761         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 762
 763         spin_lock_init(&qp->ntb_rx_pend_q_lock);
 764         spin_lock_init(&qp->ntb_rx_free_q_lock);
 765         spin_lock_init(&qp->ntb_tx_free_q_lock);
 766
 767         INIT_LIST_HEAD(&qp->rx_pend_q);
 768         INIT_LIST_HEAD(&qp->rx_free_q);
 769         INIT_LIST_HEAD(&qp->tx_free_q);
 770 }
 771
 772 int ntb_transport_init(struct pci_dev *pdev)
 773 {
 774         struct ntb_transport *nt;
 775         int rc, i;
 776
 777         nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
 778         if (!nt)
 779                 return -ENOMEM;
 780
 781         if (debugfs_initialized())
 782                 nt->debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 783         else
 784                 nt->debugfs_dir = NULL;
 785
 786         nt->ndev = ntb_register_transport(pdev, nt);
 787         if (!nt->ndev) {
 788                 rc = -EIO;
 789                 goto err;
 790         }
 791
 792         nt->max_qps = min(nt->ndev->max_cbs, max_num_clients);
 793
 794         nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
 795                           GFP_KERNEL);
 796         if (!nt->qps) {
 797                 rc = -ENOMEM;
 798                 goto err1;
 799         }
 800
 801         nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
 802
 803         for (i = 0; i < nt->max_qps; i++)
 804                 ntb_transport_init_queue(nt, i);
 805
 806         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
 807
 808         rc = ntb_register_event_callback(nt->ndev,
 809                                          ntb_transport_event_callback);
 810         if (rc)
 811                 goto err2;
 812
 813         INIT_LIST_HEAD(&nt->client_devs);
 814         rc = ntb_bus_init(nt);
 815         if (rc)
 816                 goto err3;
 817
 818         if (ntb_hw_link_status(nt->ndev))
 819                 schedule_delayed_work(&nt->link_work, 0);
 820
 821         return 0;
 822
 823 err3:
 824         ntb_unregister_event_callback(nt->ndev);
 825 err2:
 826         kfree(nt->qps);
 827 err1:
 828         ntb_unregister_transport(nt->ndev);
 829 err:
 830         debugfs_remove_recursive(nt->debugfs_dir);
 831         kfree(nt);
 832         return rc;
 833 }
 834
 835 void ntb_transport_free(void *transport)
 836 {
 837         struct ntb_transport *nt = transport;
 838         struct pci_dev *pdev;
 839         int i;
 840
 841         nt->transport_link = NTB_LINK_DOWN;
 842
 843         /* verify that all the qp's are freed */
 844         for (i = 0; i < nt->max_qps; i++)
 845                 if (!test_bit(i, &nt->qp_bitmap))
 846                         ntb_transport_free_queue(&nt->qps[i]);
 847
 848         ntb_bus_remove(nt);
 849
 850         cancel_delayed_work_sync(&nt->link_work);
 851
 852         debugfs_remove_recursive(nt->debugfs_dir);
 853
 854         ntb_unregister_event_callback(nt->ndev);
 855
 856         pdev = ntb_query_pdev(nt->ndev);
 857
 858         for (i = 0; i < NTB_NUM_MW; i++)
 859                 if (nt->mw[i].virt_addr)
 860                         dma_free_coherent(&pdev->dev, nt->mw[i].size,
 861                                           nt->mw[i].virt_addr,
 862                                           nt->mw[i].dma_addr);
 863
 864         kfree(nt->qps);
 865         ntb_unregister_transport(nt->ndev);
 866         kfree(nt);
 867 }
 868
 869 static void ntb_rx_copy_task(struct ntb_transport_qp *qp,
 870                              struct ntb_queue_entry *entry, void *offset)
 871 {
 872
 873         struct ntb_payload_header *hdr;
 874
 875         BUG_ON(offset < qp->rx_buff_begin ||
 876                offset + transport_mtu >= qp->rx_buff_end);
 877
 878         hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
 879         entry->len = hdr->len;
 880
 881         memcpy(entry->buf, offset, entry->len);
 882
 883         /* Ensure that the data is fully copied out before clearing the flag */
 884         wmb();
 885         hdr->flags = 0;
 886
 887         if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
 888                 qp->rx_handler(qp, qp->cb_data, entry->cb_data, entry->len);
 889
 890         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
 891 }
 892
 893 static int ntb_process_rxc(struct ntb_transport_qp *qp)
 894 {
 895         struct ntb_payload_header *hdr;
 896         struct ntb_queue_entry *entry;
 897         void *offset;
 898
 899         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
 900         if (!entry) {
 901                 hdr = offset + transport_mtu -
 902                       sizeof(struct ntb_payload_header);
 903                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 904                         "no buffer - HDR ver %llu, len %d, flags %x\n",
 905                         hdr->ver, hdr->len, hdr->flags);
 906                 qp->rx_err_no_buf++;
 907                 return -ENOMEM;
 908         }
 909
 910         offset = qp->rx_offset;
 911         hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
 912
 913         if (!(hdr->flags & DESC_DONE_FLAG)) {
 914                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 915                                   &qp->rx_pend_q);
 916                 qp->rx_ring_empty++;
 917                 return -EAGAIN;
 918         }
 919
 920         if (hdr->ver != qp->rx_pkts) {
 921                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 922                         "qp %d: version mismatch, expected %llu - got %llu\n",
 923                         qp->qp_num, qp->rx_pkts, hdr->ver);
 924                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 925                                   &qp->rx_pend_q);
 926                 qp->rx_err_ver++;
 927                 return -EIO;
 928         }
 929
 930         if (hdr->flags & LINK_DOWN_FLAG) {
 931                 ntb_qp_link_down(qp);
 932
 933                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 934                                   &qp->rx_pend_q);
 935
 936                 /* Ensure that the data is fully copied out before clearing the
 937                  * done flag
 938                  */
 939                 wmb();
 940                 hdr->flags = 0;
 941                 goto out;
 942         }
 943
 944         dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 945                 "rx offset %p, ver %llu - %d payload received, buf size %d\n",
 946                 qp->rx_offset, hdr->ver, hdr->len, entry->len);
 947
 948         if (hdr->len <= entry->len)
 949                 ntb_rx_copy_task(qp, entry, offset);
 950         else {
 951                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 952                                   &qp->rx_pend_q);
 953
 954                 /* Ensure that the data is fully copied out before clearing the
 955                  * done flag
 956                  */
 957                 wmb();
 958                 hdr->flags = 0;
 959                 qp->rx_err_oflow++;
 960                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 961                         "RX overflow! Wanted %d got %d\n",
 962                         hdr->len, entry->len);
 963         }
 964
 965         qp->rx_bytes += hdr->len;
 966         qp->rx_pkts++;
 967
 968 out:
 969         qp->rx_offset += transport_mtu;
 970         if (qp->rx_offset + transport_mtu >= qp->rx_buff_end)
 971                 qp->rx_offset = qp->rx_buff_begin;
 972
 973         return 0;
 974 }
 975
 976 static void ntb_transport_rx(unsigned long data)
 977 {
 978         struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
 979         int rc;
 980
 981         do {
 982                 rc = ntb_process_rxc(qp);
 983         } while (!rc);
 984 }
 985
 986 static void ntb_transport_rxc_db(void *data, int db_num)
 987 {
 988         struct ntb_transport_qp *qp = data;
 989
 990         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
 991                 __func__, db_num);
 992
 993         tasklet_schedule(&qp->rx_work);
 994 }
 995
 996 static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
 997                              struct ntb_queue_entry *entry,
 998                              void *offset)
 999 {
1000         struct ntb_payload_header *hdr;
1001
1002         BUG_ON(offset < qp->tx_mw_begin ||
1003                offset + transport_mtu >= qp->tx_mw_end);
1004
1005         memcpy_toio(offset, entry->buf, entry->len);
1006
1007         hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
1008         hdr->len = entry->len;
1009         hdr->ver = qp->tx_pkts;
1010
1011         /* Ensure that the data is fully copied out before setting the flag */
1012         mmiowb();
1013         hdr->flags = entry->flags | DESC_DONE_FLAG;
1014
1015         ntb_ring_sdb(qp->ndev, qp->qp_num);
1016
1017         /* The entry length can only be zero if the packet is intended to be a
1018          * "link down" or similar.  Since no payload is being sent in these
1019          * cases, there is nothing to add to the completion queue.
1020          */
1021         if (entry->len > 0) {
1022                 qp->tx_bytes += entry->len;
1023
1024                 if (qp->tx_handler)
1025                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1026                                        entry->len);
1027         }
1028
1029         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1030 }
1031
1032 static int ntb_process_tx(struct ntb_transport_qp *qp,
1033                           struct ntb_queue_entry *entry)
1034 {
1035         struct ntb_payload_header *hdr;
1036         void *offset;
1037
1038         offset = qp->tx_offset;
1039         hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
1040
1041         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %p, entry len %d flags %x buff %p\n",
1042                  qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags,
1043                  entry->buf);
1044         if (hdr->flags) {
1045                 qp->tx_ring_full++;
1046                 return -EAGAIN;
1047         }
1048
1049         if (entry->len > transport_mtu - sizeof(struct ntb_payload_header)) {
1050                 if (qp->tx_handler)
1051                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1052
1053                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1054                              &qp->tx_free_q);
1055                 return 0;
1056         }
1057
1058         ntb_tx_copy_task(qp, entry, offset);
1059
1060         qp->tx_offset += transport_mtu;
1061         if (qp->tx_offset + transport_mtu >= qp->tx_mw_end)
1062                 qp->tx_offset = qp->tx_mw_begin;
1063
1064         qp->tx_pkts++;
1065
1066         return 0;
1067 }
1068
1069 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1070 {
1071         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1072         struct ntb_queue_entry *entry;
1073         int i, rc;
1074
1075         if (qp->qp_link == NTB_LINK_DOWN)
1076                 return;
1077
1078         qp->qp_link = NTB_LINK_DOWN;
1079         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
1080
1081         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1082                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock,
1083                                          &qp->tx_free_q);
1084                 if (entry)
1085                         break;
1086                 msleep(100);
1087         }
1088
1089         if (!entry)
1090                 return;
1091
1092         entry->cb_data = NULL;
1093         entry->buf = NULL;
1094         entry->len = 0;
1095         entry->flags = LINK_DOWN_FLAG;
1096
1097         rc = ntb_process_tx(qp, entry);
1098         if (rc)
1099                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1100                         qp->qp_num);
1101 }
1102
1103 /**
1104  * ntb_transport_create_queue - Create a new NTB transport layer queue
1105  * @rx_handler: receive callback function
1106  * @tx_handler: transmit callback function
1107  * @event_handler: event callback function
1108  *
1109  * Create a new NTB transport layer queue and provide the queue with a callback
1110  * routine for both transmit and receive.  The receive callback routine will be
1111  * used to pass up data when the transport has received it on the queue.   The
1112  * transmit callback routine will be called when the transport has completed the
1113  * transmission of the data on the queue and the data is ready to be freed.
1114  *
1115  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1116  */
1117 struct ntb_transport_qp *
1118 ntb_transport_create_queue(void *data, struct pci_dev *pdev,
1119                            const struct ntb_queue_handlers *handlers)
1120 {
1121         struct ntb_queue_entry *entry;
1122         struct ntb_transport_qp *qp;
1123         struct ntb_transport *nt;
1124         unsigned int free_queue;
1125         int rc, i;
1126
1127         nt = ntb_find_transport(pdev);
1128         if (!nt)
1129                 goto err;
1130
1131         free_queue = ffs(nt->qp_bitmap);
1132         if (!free_queue)
1133                 goto err;
1134
1135         /* decrement free_queue to make it zero based */
1136         free_queue--;
1137
1138         clear_bit(free_queue, &nt->qp_bitmap);
1139
1140         qp = &nt->qps[free_queue];
1141         qp->cb_data = data;
1142         qp->rx_handler = handlers->rx_handler;
1143         qp->tx_handler = handlers->tx_handler;
1144         qp->event_handler = handlers->event_handler;
1145
1146         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1147                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1148                 if (!entry)
1149                         goto err1;
1150
1151                 ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1152                                   &qp->rx_free_q);
1153         }
1154
1155         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1156                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1157                 if (!entry)
1158                         goto err2;
1159
1160                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1161                                   &qp->tx_free_q);
1162         }
1163
1164         tasklet_init(&qp->rx_work, ntb_transport_rx, (unsigned long) qp);
1165
1166         rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
1167                                       ntb_transport_rxc_db);
1168         if (rc)
1169                 goto err3;
1170
1171         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1172
1173         return qp;
1174
1175 err3:
1176         tasklet_disable(&qp->rx_work);
1177 err2:
1178         while ((entry =
1179                 ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1180                 kfree(entry);
1181 err1:
1182         while ((entry =
1183                 ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1184                 kfree(entry);
1185         set_bit(free_queue, &nt->qp_bitmap);
1186 err:
1187         return NULL;
1188 }
1189 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1190
1191 /**
1192  * ntb_transport_free_queue - Frees NTB transport queue
1193  * @qp: NTB queue to be freed
1194  *
1195  * Frees NTB transport queue
1196  */
1197 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1198 {
1199         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1200         struct ntb_queue_entry *entry;
1201
1202         if (!qp)
1203                 return;
1204
1205         cancel_delayed_work_sync(&qp->link_work);
1206
1207         ntb_unregister_db_callback(qp->ndev, qp->qp_num);
1208         tasklet_disable(&qp->rx_work);
1209
1210         while ((entry =
1211                 ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1212                 kfree(entry);
1213
1214         while ((entry =
1215                 ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
1216                 dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
1217                 kfree(entry);
1218         }
1219
1220         while ((entry =
1221                 ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1222                 kfree(entry);
1223
1224         set_bit(qp->qp_num, &qp->transport->qp_bitmap);
1225
1226         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1227 }
1228 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1229
1230 /**
1231  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1232  * @qp: NTB queue to be freed
1233  * @len: pointer to variable to write enqueued buffers length
1234  *
1235  * Dequeues unused buffers from receive queue.  Should only be used during
1236  * shutdown of qp.
1237  *
1238  * RETURNS: NULL error value on error, or void* for success.
1239  */
1240 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1241 {
1242         struct ntb_queue_entry *entry;
1243         void *buf;
1244
1245         if (!qp || qp->client_ready == NTB_LINK_UP)
1246                 return NULL;
1247
1248         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1249         if (!entry)
1250                 return NULL;
1251
1252         buf = entry->cb_data;
1253         *len = entry->len;
1254
1255         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1256                           &qp->rx_free_q);
1257
1258         return buf;
1259 }
1260 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1261
1262 /**
1263  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1264  * @qp: NTB transport layer queue the entry is to be enqueued on
1265  * @cb: per buffer pointer for callback function to use
1266  * @data: pointer to data buffer that incoming packets will be copied into
1267  * @len: length of the data buffer
1268  *
1269  * Enqueue a new receive buffer onto the transport queue into which a NTB
1270  * payload can be received into.
1271  *
1272  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1273  */
1274 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1275                              unsigned int len)
1276 {
1277         struct ntb_queue_entry *entry;
1278
1279         if (!qp)
1280                 return -EINVAL;
1281
1282         entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
1283         if (!entry)
1284                 return -ENOMEM;
1285
1286         entry->cb_data = cb;
1287         entry->buf = data;
1288         entry->len = len;
1289
1290         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
1291                           &qp->rx_pend_q);
1292
1293         return 0;
1294 }
1295 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1296
1297 /**
1298  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1299  * @qp: NTB transport layer queue the entry is to be enqueued on
1300  * @cb: per buffer pointer for callback function to use
1301  * @data: pointer to data buffer that will be sent
1302  * @len: length of the data buffer
1303  *
1304  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1305  * payload will be transmitted.  This assumes that a lock is behing held to
1306  * serialize access to the qp.
1307  *
1308  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1309  */
1310 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1311                              unsigned int len)
1312 {
1313         struct ntb_queue_entry *entry;
1314         int rc;
1315
1316         if (!qp || qp->qp_link != NTB_LINK_UP || !len)
1317                 return -EINVAL;
1318
1319         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1320         if (!entry)
1321                 return -ENOMEM;
1322
1323         entry->cb_data = cb;
1324         entry->buf = data;
1325         entry->len = len;
1326         entry->flags = 0;
1327
1328         rc = ntb_process_tx(qp, entry);
1329         if (rc)
1330                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1331                              &qp->tx_free_q);
1332
1333         return rc;
1334 }
1335 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1336
1337 /**
1338  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1339  * @qp: NTB transport layer queue to be enabled
1340  *
1341  * Notify NTB transport layer of client readiness to use queue
1342  */
1343 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1344 {
1345         if (!qp)
1346                 return;
1347
1348         qp->client_ready = NTB_LINK_UP;
1349
1350         if (qp->transport->transport_link == NTB_LINK_UP)
1351                 schedule_delayed_work(&qp->link_work, 0);
1352 }
1353 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1354
1355 /**
1356  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1357  * @qp: NTB transport layer queue to be disabled
1358  *
1359  * Notify NTB transport layer of client's desire to no longer receive data on
1360  * transport queue specified.  It is the client's responsibility to ensure all
1361  * entries on queue are purged or otherwise handled appropraitely.
1362  */
1363 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1364 {
1365         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1366         int rc, val;
1367
1368         if (!qp)
1369                 return;
1370
1371         qp->client_ready = NTB_LINK_DOWN;
1372
1373         rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
1374         if (rc) {
1375                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
1376                 return;
1377         }
1378
1379         rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
1380                                    val & ~(1 << qp->qp_num));
1381         if (rc)
1382                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
1383                         val & ~(1 << qp->qp_num), QP_LINKS);
1384
1385         if (qp->qp_link == NTB_LINK_UP)
1386                 ntb_send_link_down(qp);
1387         else
1388                 cancel_delayed_work_sync(&qp->link_work);
1389 }
1390 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1391
1392 /**
1393  * ntb_transport_link_query - Query transport link state
1394  * @qp: NTB transport layer queue to be queried
1395  *
1396  * Query connectivity to the remote system of the NTB transport queue
1397  *
1398  * RETURNS: true for link up or false for link down
1399  */
1400 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1401 {
1402         return qp->qp_link == NTB_LINK_UP;
1403 }
1404 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1405
1406 /**
1407  * ntb_transport_qp_num - Query the qp number
1408  * @qp: NTB transport layer queue to be queried
1409  *
1410  * Query qp number of the NTB transport queue
1411  *
1412  * RETURNS: a zero based number specifying the qp number
1413  */
1414 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1415 {
1416         return qp->qp_num;
1417 }
1418 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1419
1420 /**
1421  * ntb_transport_max_size - Query the max payload size of a qp
1422  * @qp: NTB transport layer queue to be queried
1423  *
1424  * Query the maximum payload size permissible on the given qp
1425  *
1426  * RETURNS: the max payload size of a qp
1427  */
1428 unsigned int
1429 ntb_transport_max_size(__attribute__((unused)) struct ntb_transport_qp *qp)
1430 {
1431         return transport_mtu - sizeof(struct ntb_payload_header);
1432 }
1433 EXPORT_SYMBOL_GPL(ntb_transport_max_size);