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 unsigned 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         unsigned int tx_max_frame;
  98
  99         void (*rx_handler) (struct ntb_transport_qp *qp, void *qp_data,
 100                             void *data, int len);
 101         struct tasklet_struct rx_work;
 102         struct list_head rx_pend_q;
 103         struct list_head rx_free_q;
 104         spinlock_t ntb_rx_pend_q_lock;
 105         spinlock_t ntb_rx_free_q_lock;
 106         void *rx_buff_begin;
 107         void *rx_buff_end;
 108         void *rx_offset;
 109         unsigned int rx_max_frame;
 110
 111         void (*event_handler) (void *data, int status);
 112         struct delayed_work link_work;
 113
 114         struct dentry *debugfs_dir;
 115         struct dentry *debugfs_stats;
 116
 117         /* Stats */
 118         u64 rx_bytes;
 119         u64 rx_pkts;
 120         u64 rx_ring_empty;
 121         u64 rx_err_no_buf;
 122         u64 rx_err_oflow;
 123         u64 rx_err_ver;
 124         u64 tx_bytes;
 125         u64 tx_pkts;
 126         u64 tx_ring_full;
 127 };
 128
 129 struct ntb_transport_mw {
 130         size_t size;
 131         void *virt_addr;
 132         dma_addr_t dma_addr;
 133 };
 134
 135 struct ntb_transport_client_dev {
 136         struct list_head entry;
 137         struct device dev;
 138 };
 139
 140 struct ntb_transport {
 141         struct list_head entry;
 142         struct list_head client_devs;
 143
 144         struct ntb_device *ndev;
 145         struct ntb_transport_mw mw[NTB_NUM_MW];
 146         struct ntb_transport_qp *qps;
 147         unsigned int max_qps;
 148         unsigned long qp_bitmap;
 149         bool transport_link;
 150         struct delayed_work link_work;
 151         struct dentry *debugfs_dir;
 152 };
 153
 154 enum {
 155         DESC_DONE_FLAG = 1 << 0,
 156         LINK_DOWN_FLAG = 1 << 1,
 157 };
 158
 159 struct ntb_payload_header {
 160         u64 ver;
 161         unsigned int len;
 162         unsigned int flags;
 163 };
 164
 165 enum {
 166         VERSION = 0,
 167         MW0_SZ,
 168         MW1_SZ,
 169         NUM_QPS,
 170         QP_LINKS,
 171         MAX_SPAD,
 172 };
 173
 174 #define QP_TO_MW(qp)            ((qp) % NTB_NUM_MW)
 175 #define NTB_QP_DEF_NUM_ENTRIES  100
 176 #define NTB_LINK_DOWN_TIMEOUT   10
 177
 178 static int ntb_match_bus(struct device *dev, struct device_driver *drv)
 179 {
 180         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 181 }
 182
 183 static int ntb_client_probe(struct device *dev)
 184 {
 185         const struct ntb_client *drv = container_of(dev->driver,
 186                                                     struct ntb_client, driver);
 187         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 188         int rc = -EINVAL;
 189
 190         get_device(dev);
 191         if (drv && drv->probe)
 192                 rc = drv->probe(pdev);
 193         if (rc)
 194                 put_device(dev);
 195
 196         return rc;
 197 }
 198
 199 static int ntb_client_remove(struct device *dev)
 200 {
 201         const struct ntb_client *drv = container_of(dev->driver,
 202                                                     struct ntb_client, driver);
 203         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 204
 205         if (drv && drv->remove)
 206                 drv->remove(pdev);
 207
 208         put_device(dev);
 209
 210         return 0;
 211 }
 212
 213 struct bus_type ntb_bus_type = {
 214         .name = "ntb_bus",
 215         .match = ntb_match_bus,
 216         .probe = ntb_client_probe,
 217         .remove = ntb_client_remove,
 218 };
 219
 220 static LIST_HEAD(ntb_transport_list);
 221
 222 static int ntb_bus_init(struct ntb_transport *nt)
 223 {
 224         if (list_empty(&ntb_transport_list)) {
 225                 int rc = bus_register(&ntb_bus_type);
 226                 if (rc)
 227                         return rc;
 228         }
 229
 230         list_add(&nt->entry, &ntb_transport_list);
 231
 232         return 0;
 233 }
 234
 235 static void ntb_bus_remove(struct ntb_transport *nt)
 236 {
 237         struct ntb_transport_client_dev *client_dev, *cd;
 238
 239         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 240                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 241                         dev_name(&client_dev->dev));
 242                 list_del(&client_dev->entry);
 243                 device_unregister(&client_dev->dev);
 244         }
 245
 246         list_del(&nt->entry);
 247
 248         if (list_empty(&ntb_transport_list))
 249                 bus_unregister(&ntb_bus_type);
 250 }
 251
 252 static void ntb_client_release(struct device *dev)
 253 {
 254         struct ntb_transport_client_dev *client_dev;
 255         client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
 256
 257         kfree(client_dev);
 258 }
 259
 260 /**
 261  * ntb_unregister_client_dev - Unregister NTB client device
 262  * @device_name: Name of NTB client device
 263  *
 264  * Unregister an NTB client device with the NTB transport layer
 265  */
 266 void ntb_unregister_client_dev(char *device_name)
 267 {
 268         struct ntb_transport_client_dev *client, *cd;
 269         struct ntb_transport *nt;
 270
 271         list_for_each_entry(nt, &ntb_transport_list, entry)
 272                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 273                         if (!strncmp(dev_name(&client->dev), device_name,
 274                                      strlen(device_name))) {
 275                                 list_del(&client->entry);
 276                                 device_unregister(&client->dev);
 277                         }
 278 }
 279 EXPORT_SYMBOL_GPL(ntb_unregister_client_dev);
 280
 281 /**
 282  * ntb_register_client_dev - Register NTB client device
 283  * @device_name: Name of NTB client device
 284  *
 285  * Register an NTB client device with the NTB transport layer
 286  */
 287 int ntb_register_client_dev(char *device_name)
 288 {
 289         struct ntb_transport_client_dev *client_dev;
 290         struct ntb_transport *nt;
 291         int rc;
 292
 293         if (list_empty(&ntb_transport_list))
 294                 return -ENODEV;
 295
 296         list_for_each_entry(nt, &ntb_transport_list, entry) {
 297                 struct device *dev;
 298
 299                 client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
 300                                      GFP_KERNEL);
 301                 if (!client_dev) {
 302                         rc = -ENOMEM;
 303                         goto err;
 304                 }
 305
 306                 dev = &client_dev->dev;
 307
 308                 /* setup and register client devices */
 309                 dev_set_name(dev, "%s", device_name);
 310                 dev->bus = &ntb_bus_type;
 311                 dev->release = ntb_client_release;
 312                 dev->parent = &ntb_query_pdev(nt->ndev)->dev;
 313
 314                 rc = device_register(dev);
 315                 if (rc) {
 316                         kfree(client_dev);
 317                         goto err;
 318                 }
 319
 320                 list_add_tail(&client_dev->entry, &nt->client_devs);
 321         }
 322
 323         return 0;
 324
 325 err:
 326         ntb_unregister_client_dev(device_name);
 327
 328         return rc;
 329 }
 330 EXPORT_SYMBOL_GPL(ntb_register_client_dev);
 331
 332 /**
 333  * ntb_register_client - Register NTB client driver
 334  * @drv: NTB client driver to be registered
 335  *
 336  * Register an NTB client driver with the NTB transport layer
 337  *
 338  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 339  */
 340 int ntb_register_client(struct ntb_client *drv)
 341 {
 342         drv->driver.bus = &ntb_bus_type;
 343
 344         if (list_empty(&ntb_transport_list))
 345                 return -ENODEV;
 346
 347         return driver_register(&drv->driver);
 348 }
 349 EXPORT_SYMBOL_GPL(ntb_register_client);
 350
 351 /**
 352  * ntb_unregister_client - Unregister NTB client driver
 353  * @drv: NTB client driver to be unregistered
 354  *
 355  * Unregister an NTB client driver with the NTB transport layer
 356  *
 357  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 358  */
 359 void ntb_unregister_client(struct ntb_client *drv)
 360 {
 361         driver_unregister(&drv->driver);
 362 }
 363 EXPORT_SYMBOL_GPL(ntb_unregister_client);
 364
 365 static int debugfs_open(struct inode *inode, struct file *filp)
 366 {
 367         filp->private_data = inode->i_private;
 368         return 0;
 369 }
 370
 371 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 372                             loff_t *offp)
 373 {
 374         struct ntb_transport_qp *qp;
 375         char buf[1024];
 376         ssize_t ret, out_offset, out_count;
 377
 378         out_count = 1024;
 379
 380         qp = filp->private_data;
 381         out_offset = 0;
 382         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 383                                "NTB QP stats\n");
 384         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 385                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 386         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 387                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 388         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 389                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 390         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 391                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 392         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 393                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 394         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 395                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 396         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 397                                "rx_buff_begin - %p\n", qp->rx_buff_begin);
 398         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 399                                "rx_offset - \t%p\n", qp->rx_offset);
 400         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 401                                "rx_buff_end - \t%p\n", qp->rx_buff_end);
 402
 403         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 404                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 405         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 406                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 407         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 408                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 409         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 410                                "tx_mw_begin - \t%p\n", qp->tx_mw_begin);
 411         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 412                                "tx_offset - \t%p\n", qp->tx_offset);
 413         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 414                                "tx_mw_end - \t%p\n", qp->tx_mw_end);
 415
 416         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 417                                "QP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
 418                                "Up" : "Down");
 419
 420         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 421         return ret;
 422 }
 423
 424 static const struct file_operations ntb_qp_debugfs_stats = {
 425         .owner = THIS_MODULE,
 426         .open = debugfs_open,
 427         .read = debugfs_read,
 428 };
 429
 430 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 431                          struct list_head *list)
 432 {
 433         unsigned long flags;
 434
 435         spin_lock_irqsave(lock, flags);
 436         list_add_tail(entry, list);
 437         spin_unlock_irqrestore(lock, flags);
 438 }
 439
 440 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 441                                                 struct list_head *list)
 442 {
 443         struct ntb_queue_entry *entry;
 444         unsigned long flags;
 445
 446         spin_lock_irqsave(lock, flags);
 447         if (list_empty(list)) {
 448                 entry = NULL;
 449                 goto out;
 450         }
 451         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 452         list_del(&entry->entry);
 453 out:
 454         spin_unlock_irqrestore(lock, flags);
 455
 456         return entry;
 457 }
 458
 459 static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
 460                                       unsigned int qp_num)
 461 {
 462         struct ntb_transport_qp *qp = &nt->qps[qp_num];
 463         unsigned int rx_size, num_qps_mw;
 464         u8 mw_num = QP_TO_MW(qp_num);
 465         void *offset;
 466
 467         WARN_ON(nt->mw[mw_num].virt_addr == 0);
 468
 469         if (nt->max_qps % NTB_NUM_MW && mw_num < nt->max_qps % NTB_NUM_MW)
 470                 num_qps_mw = nt->max_qps / NTB_NUM_MW + 1;
 471         else
 472                 num_qps_mw = nt->max_qps / NTB_NUM_MW;
 473
 474         rx_size = nt->mw[mw_num].size / num_qps_mw;
 475         qp->rx_buff_begin = nt->mw[mw_num].virt_addr +
 476                             (qp_num / NTB_NUM_MW * rx_size);
 477         qp->rx_buff_end = qp->rx_buff_begin + rx_size;
 478         qp->rx_offset = qp->rx_buff_begin;
 479         qp->rx_max_frame = min(transport_mtu, rx_size);
 480
 481         /* setup the hdr offsets with 0's */
 482         for (offset = qp->rx_buff_begin + qp->rx_max_frame -
 483                       sizeof(struct ntb_payload_header);
 484              offset < qp->rx_buff_end; offset += qp->rx_max_frame)
 485                 memset(offset, 0, sizeof(struct ntb_payload_header));
 486
 487         qp->rx_pkts = 0;
 488         qp->tx_pkts = 0;
 489 }
 490
 491 static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
 492 {
 493         struct ntb_transport_mw *mw = &nt->mw[num_mw];
 494         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 495
 496         /* Alloc memory for receiving data.  Must be 4k aligned */
 497         mw->size = ALIGN(size, 4096);
 498
 499         mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
 500                                            GFP_KERNEL);
 501         if (!mw->virt_addr) {
 502                 dev_err(&pdev->dev, "Unable to allocate MW buffer of size %d\n",
 503                        (int) mw->size);
 504                 return -ENOMEM;
 505         }
 506
 507         /* Notify HW the memory location of the receive buffer */
 508         ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
 509
 510         return 0;
 511 }
 512
 513 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 514 {
 515         struct ntb_transport *nt = qp->transport;
 516         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 517
 518         if (qp->qp_link == NTB_LINK_DOWN) {
 519                 cancel_delayed_work_sync(&qp->link_work);
 520                 return;
 521         }
 522
 523         if (qp->event_handler)
 524                 qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
 525
 526         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
 527         qp->qp_link = NTB_LINK_DOWN;
 528
 529         if (nt->transport_link == NTB_LINK_UP)
 530                 schedule_delayed_work(&qp->link_work,
 531                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 532 }
 533
 534 static void ntb_transport_conn_down(struct ntb_transport *nt)
 535 {
 536         int i;
 537
 538         if (nt->transport_link == NTB_LINK_DOWN)
 539                 cancel_delayed_work_sync(&nt->link_work);
 540         else
 541                 nt->transport_link = NTB_LINK_DOWN;
 542
 543         /* Pass along the info to any clients */
 544         for (i = 0; i < nt->max_qps; i++)
 545                 if (!test_bit(i, &nt->qp_bitmap))
 546                         ntb_qp_link_down(&nt->qps[i]);
 547
 548         /* The scratchpad registers keep the values if the remote side
 549          * goes down, blast them now to give them a sane value the next
 550          * time they are accessed
 551          */
 552         for (i = 0; i < MAX_SPAD; i++)
 553                 ntb_write_local_spad(nt->ndev, i, 0);
 554 }
 555
 556 static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
 557 {
 558         struct ntb_transport *nt = data;
 559
 560         switch (event) {
 561         case NTB_EVENT_HW_LINK_UP:
 562                 schedule_delayed_work(&nt->link_work, 0);
 563                 break;
 564         case NTB_EVENT_HW_LINK_DOWN:
 565                 ntb_transport_conn_down(nt);
 566                 break;
 567         default:
 568                 BUG();
 569         }
 570 }
 571
 572 static void ntb_transport_link_work(struct work_struct *work)
 573 {
 574         struct ntb_transport *nt = container_of(work, struct ntb_transport,
 575                                                 link_work.work);
 576         struct ntb_device *ndev = nt->ndev;
 577         struct pci_dev *pdev = ntb_query_pdev(ndev);
 578         u32 val;
 579         int rc, i;
 580
 581         /* send the local info */
 582         rc = ntb_write_remote_spad(ndev, VERSION, NTB_TRANSPORT_VERSION);
 583         if (rc) {
 584                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 585                         0, VERSION);
 586                 goto out;
 587         }
 588
 589         rc = ntb_write_remote_spad(ndev, MW0_SZ, ntb_get_mw_size(ndev, 0));
 590         if (rc) {
 591                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 592                         (u32) ntb_get_mw_size(ndev, 0), MW0_SZ);
 593                 goto out;
 594         }
 595
 596         rc = ntb_write_remote_spad(ndev, MW1_SZ, ntb_get_mw_size(ndev, 1));
 597         if (rc) {
 598                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 599                         (u32) ntb_get_mw_size(ndev, 1), MW1_SZ);
 600                 goto out;
 601         }
 602
 603         rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
 604         if (rc) {
 605                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 606                         nt->max_qps, NUM_QPS);
 607                 goto out;
 608         }
 609
 610         rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
 611         if (rc) {
 612                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
 613                 goto out;
 614         }
 615
 616         rc = ntb_write_remote_spad(ndev, QP_LINKS, val);
 617         if (rc) {
 618                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 619                         val, QP_LINKS);
 620                 goto out;
 621         }
 622
 623         /* Query the remote side for its info */
 624         rc = ntb_read_remote_spad(ndev, VERSION, &val);
 625         if (rc) {
 626                 dev_err(&pdev->dev, "Error reading remote spad %d\n", VERSION);
 627                 goto out;
 628         }
 629
 630         if (val != NTB_TRANSPORT_VERSION)
 631                 goto out;
 632         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 633
 634         rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
 635         if (rc) {
 636                 dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
 637                 goto out;
 638         }
 639
 640         if (val != nt->max_qps)
 641                 goto out;
 642         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 643
 644         rc = ntb_read_remote_spad(ndev, MW0_SZ, &val);
 645         if (rc) {
 646                 dev_err(&pdev->dev, "Error reading remote spad %d\n", MW0_SZ);
 647                 goto out;
 648         }
 649
 650         if (!val)
 651                 goto out;
 652         dev_dbg(&pdev->dev, "Remote MW0 size = %d\n", val);
 653
 654         rc = ntb_set_mw(nt, 0, val);
 655         if (rc)
 656                 goto out;
 657
 658         rc = ntb_read_remote_spad(ndev, MW1_SZ, &val);
 659         if (rc) {
 660                 dev_err(&pdev->dev, "Error reading remote spad %d\n", MW1_SZ);
 661                 goto out;
 662         }
 663
 664         if (!val)
 665                 goto out;
 666         dev_dbg(&pdev->dev, "Remote MW1 size = %d\n", val);
 667
 668         rc = ntb_set_mw(nt, 1, val);
 669         if (rc)
 670                 goto out;
 671
 672         nt->transport_link = NTB_LINK_UP;
 673
 674         for (i = 0; i < nt->max_qps; i++) {
 675                 struct ntb_transport_qp *qp = &nt->qps[i];
 676
 677                 ntb_transport_setup_qp_mw(nt, i);
 678
 679                 if (qp->client_ready == NTB_LINK_UP)
 680                         schedule_delayed_work(&qp->link_work, 0);
 681         }
 682
 683         return;
 684
 685 out:
 686         if (ntb_hw_link_status(ndev))
 687                 schedule_delayed_work(&nt->link_work,
 688                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 689 }
 690
 691 static void ntb_qp_link_work(struct work_struct *work)
 692 {
 693         struct ntb_transport_qp *qp = container_of(work,
 694                                                    struct ntb_transport_qp,
 695                                                    link_work.work);
 696         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
 697         struct ntb_transport *nt = qp->transport;
 698         int rc, val;
 699
 700         WARN_ON(nt->transport_link != NTB_LINK_UP);
 701
 702         rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
 703         if (rc) {
 704                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
 705                 return;
 706         }
 707
 708         rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
 709         if (rc)
 710                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 711                         val | 1 << qp->qp_num, QP_LINKS);
 712
 713         /* query remote spad for qp ready bits */
 714         rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
 715         if (rc)
 716                 dev_err(&pdev->dev, "Error reading remote spad %d\n", QP_LINKS);
 717
 718         dev_dbg(&pdev->dev, "Remote QP link status = %x\n", val);
 719
 720         /* See if the remote side is up */
 721         if (1 << qp->qp_num & val) {
 722                 qp->qp_link = NTB_LINK_UP;
 723
 724                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 725                 if (qp->event_handler)
 726                         qp->event_handler(qp->cb_data, NTB_LINK_UP);
 727         } else if (nt->transport_link == NTB_LINK_UP)
 728                 schedule_delayed_work(&qp->link_work,
 729                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 730 }
 731
 732 static void ntb_transport_init_queue(struct ntb_transport *nt,
 733                                      unsigned int qp_num)
 734 {
 735         struct ntb_transport_qp *qp;
 736         unsigned int num_qps_mw, tx_size;
 737         u8 mw_num = QP_TO_MW(qp_num);
 738
 739         qp = &nt->qps[qp_num];
 740         qp->qp_num = qp_num;
 741         qp->transport = nt;
 742         qp->ndev = nt->ndev;
 743         qp->qp_link = NTB_LINK_DOWN;
 744         qp->client_ready = NTB_LINK_DOWN;
 745         qp->event_handler = NULL;
 746
 747         if (nt->max_qps % NTB_NUM_MW && mw_num < nt->max_qps % NTB_NUM_MW)
 748                 num_qps_mw = nt->max_qps / NTB_NUM_MW + 1;
 749         else
 750                 num_qps_mw = nt->max_qps / NTB_NUM_MW;
 751
 752         tx_size = ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw;
 753         qp->tx_mw_begin = ntb_get_mw_vbase(nt->ndev, mw_num) +
 754                           (qp_num / NTB_NUM_MW * tx_size);
 755         qp->tx_mw_end = qp->tx_mw_begin + tx_size;
 756         qp->tx_offset = qp->tx_mw_begin;
 757         qp->tx_max_frame = min(transport_mtu, tx_size);
 758
 759         if (nt->debugfs_dir) {
 760                 char debugfs_name[4];
 761
 762                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 763                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 764                                                      nt->debugfs_dir);
 765
 766                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 767                                                         qp->debugfs_dir, qp,
 768                                                         &ntb_qp_debugfs_stats);
 769         }
 770
 771         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 772
 773         spin_lock_init(&qp->ntb_rx_pend_q_lock);
 774         spin_lock_init(&qp->ntb_rx_free_q_lock);
 775         spin_lock_init(&qp->ntb_tx_free_q_lock);
 776
 777         INIT_LIST_HEAD(&qp->rx_pend_q);
 778         INIT_LIST_HEAD(&qp->rx_free_q);
 779         INIT_LIST_HEAD(&qp->tx_free_q);
 780 }
 781
 782 int ntb_transport_init(struct pci_dev *pdev)
 783 {
 784         struct ntb_transport *nt;
 785         int rc, i;
 786
 787         nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
 788         if (!nt)
 789                 return -ENOMEM;
 790
 791         if (debugfs_initialized())
 792                 nt->debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 793         else
 794                 nt->debugfs_dir = NULL;
 795
 796         nt->ndev = ntb_register_transport(pdev, nt);
 797         if (!nt->ndev) {
 798                 rc = -EIO;
 799                 goto err;
 800         }
 801
 802         nt->max_qps = min(nt->ndev->max_cbs, max_num_clients);
 803
 804         nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
 805                           GFP_KERNEL);
 806         if (!nt->qps) {
 807                 rc = -ENOMEM;
 808                 goto err1;
 809         }
 810
 811         nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
 812
 813         for (i = 0; i < nt->max_qps; i++)
 814                 ntb_transport_init_queue(nt, i);
 815
 816         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
 817
 818         rc = ntb_register_event_callback(nt->ndev,
 819                                          ntb_transport_event_callback);
 820         if (rc)
 821                 goto err2;
 822
 823         INIT_LIST_HEAD(&nt->client_devs);
 824         rc = ntb_bus_init(nt);
 825         if (rc)
 826                 goto err3;
 827
 828         if (ntb_hw_link_status(nt->ndev))
 829                 schedule_delayed_work(&nt->link_work, 0);
 830
 831         return 0;
 832
 833 err3:
 834         ntb_unregister_event_callback(nt->ndev);
 835 err2:
 836         kfree(nt->qps);
 837 err1:
 838         ntb_unregister_transport(nt->ndev);
 839 err:
 840         debugfs_remove_recursive(nt->debugfs_dir);
 841         kfree(nt);
 842         return rc;
 843 }
 844
 845 void ntb_transport_free(void *transport)
 846 {
 847         struct ntb_transport *nt = transport;
 848         struct pci_dev *pdev;
 849         int i;
 850
 851         nt->transport_link = NTB_LINK_DOWN;
 852
 853         /* verify that all the qp's are freed */
 854         for (i = 0; i < nt->max_qps; i++)
 855                 if (!test_bit(i, &nt->qp_bitmap))
 856                         ntb_transport_free_queue(&nt->qps[i]);
 857
 858         ntb_bus_remove(nt);
 859
 860         cancel_delayed_work_sync(&nt->link_work);
 861
 862         debugfs_remove_recursive(nt->debugfs_dir);
 863
 864         ntb_unregister_event_callback(nt->ndev);
 865
 866         pdev = ntb_query_pdev(nt->ndev);
 867
 868         for (i = 0; i < NTB_NUM_MW; i++)
 869                 if (nt->mw[i].virt_addr)
 870                         dma_free_coherent(&pdev->dev, nt->mw[i].size,
 871                                           nt->mw[i].virt_addr,
 872                                           nt->mw[i].dma_addr);
 873
 874         kfree(nt->qps);
 875         ntb_unregister_transport(nt->ndev);
 876         kfree(nt);
 877 }
 878
 879 static void ntb_rx_copy_task(struct ntb_transport_qp *qp,
 880                              struct ntb_queue_entry *entry, void *offset)
 881 {
 882
 883         struct ntb_payload_header *hdr;
 884
 885         BUG_ON(offset < qp->rx_buff_begin ||
 886                offset + qp->rx_max_frame >= qp->rx_buff_end);
 887
 888         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
 889         entry->len = hdr->len;
 890
 891         memcpy(entry->buf, offset, entry->len);
 892
 893         /* Ensure that the data is fully copied out before clearing the flag */
 894         wmb();
 895         hdr->flags = 0;
 896
 897         if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
 898                 qp->rx_handler(qp, qp->cb_data, entry->cb_data, entry->len);
 899
 900         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
 901 }
 902
 903 static int ntb_process_rxc(struct ntb_transport_qp *qp)
 904 {
 905         struct ntb_payload_header *hdr;
 906         struct ntb_queue_entry *entry;
 907         void *offset;
 908
 909         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
 910         if (!entry) {
 911                 hdr = offset + qp->rx_max_frame -
 912                       sizeof(struct ntb_payload_header);
 913                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 914                         "no buffer - HDR ver %llu, len %d, flags %x\n",
 915                         hdr->ver, hdr->len, hdr->flags);
 916                 qp->rx_err_no_buf++;
 917                 return -ENOMEM;
 918         }
 919
 920         offset = qp->rx_offset;
 921         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
 922
 923         if (!(hdr->flags & DESC_DONE_FLAG)) {
 924                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 925                                   &qp->rx_pend_q);
 926                 qp->rx_ring_empty++;
 927                 return -EAGAIN;
 928         }
 929
 930         if (hdr->ver != qp->rx_pkts) {
 931                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 932                         "qp %d: version mismatch, expected %llu - got %llu\n",
 933                         qp->qp_num, qp->rx_pkts, hdr->ver);
 934                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 935                                   &qp->rx_pend_q);
 936                 qp->rx_err_ver++;
 937                 return -EIO;
 938         }
 939
 940         if (hdr->flags & LINK_DOWN_FLAG) {
 941                 ntb_qp_link_down(qp);
 942
 943                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 944                                   &qp->rx_pend_q);
 945
 946                 /* Ensure that the data is fully copied out before clearing the
 947                  * done flag
 948                  */
 949                 wmb();
 950                 hdr->flags = 0;
 951                 goto out;
 952         }
 953
 954         dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 955                 "rx offset %p, ver %llu - %d payload received, buf size %d\n",
 956                 qp->rx_offset, hdr->ver, hdr->len, entry->len);
 957
 958         if (hdr->len <= entry->len)
 959                 ntb_rx_copy_task(qp, entry, offset);
 960         else {
 961                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
 962                                   &qp->rx_pend_q);
 963
 964                 /* Ensure that the data is fully copied out before clearing the
 965                  * done flag
 966                  */
 967                 wmb();
 968                 hdr->flags = 0;
 969                 qp->rx_err_oflow++;
 970                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
 971                         "RX overflow! Wanted %d got %d\n",
 972                         hdr->len, entry->len);
 973         }
 974
 975         qp->rx_bytes += hdr->len;
 976         qp->rx_pkts++;
 977
 978 out:
 979         qp->rx_offset += qp->rx_max_frame;
 980         if (qp->rx_offset + qp->rx_max_frame >= qp->rx_buff_end)
 981                 qp->rx_offset = qp->rx_buff_begin;
 982
 983         return 0;
 984 }
 985
 986 static void ntb_transport_rx(unsigned long data)
 987 {
 988         struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
 989         int rc;
 990
 991         do {
 992                 rc = ntb_process_rxc(qp);
 993         } while (!rc);
 994 }
 995
 996 static void ntb_transport_rxc_db(void *data, int db_num)
 997 {
 998         struct ntb_transport_qp *qp = data;
 999
1000         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
1001                 __func__, db_num);
1002
1003         tasklet_schedule(&qp->rx_work);
1004 }
1005
1006 static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
1007                              struct ntb_queue_entry *entry,
1008                              void *offset)
1009 {
1010         struct ntb_payload_header *hdr;
1011
1012         BUG_ON(offset < qp->tx_mw_begin ||
1013                offset + qp->tx_max_frame >= qp->tx_mw_end);
1014
1015         memcpy_toio(offset, entry->buf, entry->len);
1016
1017         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1018         hdr->len = entry->len;
1019         hdr->ver = qp->tx_pkts;
1020
1021         /* Ensure that the data is fully copied out before setting the flag */
1022         wmb();
1023         hdr->flags = entry->flags | DESC_DONE_FLAG;
1024
1025         ntb_ring_sdb(qp->ndev, qp->qp_num);
1026
1027         /* The entry length can only be zero if the packet is intended to be a
1028          * "link down" or similar.  Since no payload is being sent in these
1029          * cases, there is nothing to add to the completion queue.
1030          */
1031         if (entry->len > 0) {
1032                 qp->tx_bytes += entry->len;
1033
1034                 if (qp->tx_handler)
1035                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1036                                        entry->len);
1037         }
1038
1039         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1040 }
1041
1042 static int ntb_process_tx(struct ntb_transport_qp *qp,
1043                           struct ntb_queue_entry *entry)
1044 {
1045         struct ntb_payload_header *hdr;
1046         void *offset;
1047
1048         offset = qp->tx_offset;
1049         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1050
1051         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %p, entry len %d flags %x buff %p\n",
1052                  qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags,
1053                  entry->buf);
1054         if (hdr->flags) {
1055                 qp->tx_ring_full++;
1056                 return -EAGAIN;
1057         }
1058
1059         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1060                 if (qp->tx_handler)
1061                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1062
1063                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1064                              &qp->tx_free_q);
1065                 return 0;
1066         }
1067
1068         ntb_tx_copy_task(qp, entry, offset);
1069
1070         qp->tx_offset += qp->tx_max_frame;
1071         if (qp->tx_offset + qp->tx_max_frame >= qp->tx_mw_end)
1072                 qp->tx_offset = qp->tx_mw_begin;
1073
1074         qp->tx_pkts++;
1075
1076         return 0;
1077 }
1078
1079 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1080 {
1081         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1082         struct ntb_queue_entry *entry;
1083         int i, rc;
1084
1085         if (qp->qp_link == NTB_LINK_DOWN)
1086                 return;
1087
1088         qp->qp_link = NTB_LINK_DOWN;
1089         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
1090
1091         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1092                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock,
1093                                          &qp->tx_free_q);
1094                 if (entry)
1095                         break;
1096                 msleep(100);
1097         }
1098
1099         if (!entry)
1100                 return;
1101
1102         entry->cb_data = NULL;
1103         entry->buf = NULL;
1104         entry->len = 0;
1105         entry->flags = LINK_DOWN_FLAG;
1106
1107         rc = ntb_process_tx(qp, entry);
1108         if (rc)
1109                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1110                         qp->qp_num);
1111 }
1112
1113 /**
1114  * ntb_transport_create_queue - Create a new NTB transport layer queue
1115  * @rx_handler: receive callback function
1116  * @tx_handler: transmit callback function
1117  * @event_handler: event callback function
1118  *
1119  * Create a new NTB transport layer queue and provide the queue with a callback
1120  * routine for both transmit and receive.  The receive callback routine will be
1121  * used to pass up data when the transport has received it on the queue.   The
1122  * transmit callback routine will be called when the transport has completed the
1123  * transmission of the data on the queue and the data is ready to be freed.
1124  *
1125  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1126  */
1127 struct ntb_transport_qp *
1128 ntb_transport_create_queue(void *data, struct pci_dev *pdev,
1129                            const struct ntb_queue_handlers *handlers)
1130 {
1131         struct ntb_queue_entry *entry;
1132         struct ntb_transport_qp *qp;
1133         struct ntb_transport *nt;
1134         unsigned int free_queue;
1135         int rc, i;
1136
1137         nt = ntb_find_transport(pdev);
1138         if (!nt)
1139                 goto err;
1140
1141         free_queue = ffs(nt->qp_bitmap);
1142         if (!free_queue)
1143                 goto err;
1144
1145         /* decrement free_queue to make it zero based */
1146         free_queue--;
1147
1148         clear_bit(free_queue, &nt->qp_bitmap);
1149
1150         qp = &nt->qps[free_queue];
1151         qp->cb_data = data;
1152         qp->rx_handler = handlers->rx_handler;
1153         qp->tx_handler = handlers->tx_handler;
1154         qp->event_handler = handlers->event_handler;
1155
1156         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1157                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1158                 if (!entry)
1159                         goto err1;
1160
1161                 ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1162                                   &qp->rx_free_q);
1163         }
1164
1165         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1166                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1167                 if (!entry)
1168                         goto err2;
1169
1170                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1171                                   &qp->tx_free_q);
1172         }
1173
1174         tasklet_init(&qp->rx_work, ntb_transport_rx, (unsigned long) qp);
1175
1176         rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
1177                                       ntb_transport_rxc_db);
1178         if (rc)
1179                 goto err3;
1180
1181         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1182
1183         return qp;
1184
1185 err3:
1186         tasklet_disable(&qp->rx_work);
1187 err2:
1188         while ((entry =
1189                 ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1190                 kfree(entry);
1191 err1:
1192         while ((entry =
1193                 ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1194                 kfree(entry);
1195         set_bit(free_queue, &nt->qp_bitmap);
1196 err:
1197         return NULL;
1198 }
1199 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1200
1201 /**
1202  * ntb_transport_free_queue - Frees NTB transport queue
1203  * @qp: NTB queue to be freed
1204  *
1205  * Frees NTB transport queue
1206  */
1207 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1208 {
1209         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1210         struct ntb_queue_entry *entry;
1211
1212         if (!qp)
1213                 return;
1214
1215         cancel_delayed_work_sync(&qp->link_work);
1216
1217         ntb_unregister_db_callback(qp->ndev, qp->qp_num);
1218         tasklet_disable(&qp->rx_work);
1219
1220         while ((entry =
1221                 ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1222                 kfree(entry);
1223
1224         while ((entry =
1225                 ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
1226                 dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
1227                 kfree(entry);
1228         }
1229
1230         while ((entry =
1231                 ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1232                 kfree(entry);
1233
1234         set_bit(qp->qp_num, &qp->transport->qp_bitmap);
1235
1236         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1237 }
1238 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1239
1240 /**
1241  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1242  * @qp: NTB queue to be freed
1243  * @len: pointer to variable to write enqueued buffers length
1244  *
1245  * Dequeues unused buffers from receive queue.  Should only be used during
1246  * shutdown of qp.
1247  *
1248  * RETURNS: NULL error value on error, or void* for success.
1249  */
1250 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1251 {
1252         struct ntb_queue_entry *entry;
1253         void *buf;
1254
1255         if (!qp || qp->client_ready == NTB_LINK_UP)
1256                 return NULL;
1257
1258         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1259         if (!entry)
1260                 return NULL;
1261
1262         buf = entry->cb_data;
1263         *len = entry->len;
1264
1265         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1266                           &qp->rx_free_q);
1267
1268         return buf;
1269 }
1270 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1271
1272 /**
1273  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1274  * @qp: NTB transport layer queue the entry is to be enqueued on
1275  * @cb: per buffer pointer for callback function to use
1276  * @data: pointer to data buffer that incoming packets will be copied into
1277  * @len: length of the data buffer
1278  *
1279  * Enqueue a new receive buffer onto the transport queue into which a NTB
1280  * payload can be received into.
1281  *
1282  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1283  */
1284 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1285                              unsigned int len)
1286 {
1287         struct ntb_queue_entry *entry;
1288
1289         if (!qp)
1290                 return -EINVAL;
1291
1292         entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
1293         if (!entry)
1294                 return -ENOMEM;
1295
1296         entry->cb_data = cb;
1297         entry->buf = data;
1298         entry->len = len;
1299
1300         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
1301                           &qp->rx_pend_q);
1302
1303         return 0;
1304 }
1305 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1306
1307 /**
1308  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1309  * @qp: NTB transport layer queue the entry is to be enqueued on
1310  * @cb: per buffer pointer for callback function to use
1311  * @data: pointer to data buffer that will be sent
1312  * @len: length of the data buffer
1313  *
1314  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1315  * payload will be transmitted.  This assumes that a lock is behing held to
1316  * serialize access to the qp.
1317  *
1318  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1319  */
1320 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1321                              unsigned int len)
1322 {
1323         struct ntb_queue_entry *entry;
1324         int rc;
1325
1326         if (!qp || qp->qp_link != NTB_LINK_UP || !len)
1327                 return -EINVAL;
1328
1329         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1330         if (!entry)
1331                 return -ENOMEM;
1332
1333         entry->cb_data = cb;
1334         entry->buf = data;
1335         entry->len = len;
1336         entry->flags = 0;
1337
1338         rc = ntb_process_tx(qp, entry);
1339         if (rc)
1340                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1341                              &qp->tx_free_q);
1342
1343         return rc;
1344 }
1345 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1346
1347 /**
1348  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1349  * @qp: NTB transport layer queue to be enabled
1350  *
1351  * Notify NTB transport layer of client readiness to use queue
1352  */
1353 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1354 {
1355         if (!qp)
1356                 return;
1357
1358         qp->client_ready = NTB_LINK_UP;
1359
1360         if (qp->transport->transport_link == NTB_LINK_UP)
1361                 schedule_delayed_work(&qp->link_work, 0);
1362 }
1363 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1364
1365 /**
1366  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1367  * @qp: NTB transport layer queue to be disabled
1368  *
1369  * Notify NTB transport layer of client's desire to no longer receive data on
1370  * transport queue specified.  It is the client's responsibility to ensure all
1371  * entries on queue are purged or otherwise handled appropraitely.
1372  */
1373 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1374 {
1375         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1376         int rc, val;
1377
1378         if (!qp)
1379                 return;
1380
1381         qp->client_ready = NTB_LINK_DOWN;
1382
1383         rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
1384         if (rc) {
1385                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
1386                 return;
1387         }
1388
1389         rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
1390                                    val & ~(1 << qp->qp_num));
1391         if (rc)
1392                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
1393                         val & ~(1 << qp->qp_num), QP_LINKS);
1394
1395         if (qp->qp_link == NTB_LINK_UP)
1396                 ntb_send_link_down(qp);
1397         else
1398                 cancel_delayed_work_sync(&qp->link_work);
1399 }
1400 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1401
1402 /**
1403  * ntb_transport_link_query - Query transport link state
1404  * @qp: NTB transport layer queue to be queried
1405  *
1406  * Query connectivity to the remote system of the NTB transport queue
1407  *
1408  * RETURNS: true for link up or false for link down
1409  */
1410 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1411 {
1412         return qp->qp_link == NTB_LINK_UP;
1413 }
1414 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1415
1416 /**
1417  * ntb_transport_qp_num - Query the qp number
1418  * @qp: NTB transport layer queue to be queried
1419  *
1420  * Query qp number of the NTB transport queue
1421  *
1422  * RETURNS: a zero based number specifying the qp number
1423  */
1424 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1425 {
1426         return qp->qp_num;
1427 }
1428 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1429
1430 /**
1431  * ntb_transport_max_size - Query the max payload size of a qp
1432  * @qp: NTB transport layer queue to be queried
1433  *
1434  * Query the maximum payload size permissible on the given qp
1435  *
1436  * RETURNS: the max payload size of a qp
1437  */
1438 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1439 {
1440         return qp->tx_max_frame - sizeof(struct ntb_payload_header);
1441 }
1442 EXPORT_SYMBOL_GPL(ntb_transport_max_size);