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/dmaengine.h>
  51 #include <linux/dma-mapping.h>
  52 #include <linux/errno.h>
  53 #include <linux/export.h>
  54 #include <linux/interrupt.h>
  55 #include <linux/module.h>
  56 #include <linux/pci.h>
  57 #include <linux/slab.h>
  58 #include <linux/types.h>
  59 #include <linux/ntb.h>
  60 #include "ntb_hw.h"
  61
  62 #define NTB_TRANSPORT_VERSION   3
  63
  64 static unsigned int transport_mtu = 0x401E;
  65 module_param(transport_mtu, uint, 0644);
  66 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
  67
  68 static unsigned char max_num_clients;
  69 module_param(max_num_clients, byte, 0644);
  70 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
  71
  72 static unsigned int copy_bytes = 1024;
  73 module_param(copy_bytes, uint, 0644);
  74 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
  75
  76 struct ntb_queue_entry {
  77         /* ntb_queue list reference */
  78         struct list_head entry;
  79         /* pointers to data to be transfered */
  80         void *cb_data;
  81         void *buf;
  82         unsigned int len;
  83         unsigned int flags;
  84
  85         struct ntb_transport_qp *qp;
  86         union {
  87                 struct ntb_payload_header __iomem *tx_hdr;
  88                 struct ntb_payload_header *rx_hdr;
  89         };
  90         unsigned int index;
  91 };
  92
  93 struct ntb_rx_info {
  94         unsigned int entry;
  95 };
  96
  97 struct ntb_transport_qp {
  98         struct ntb_transport *transport;
  99         struct ntb_device *ndev;
 100         void *cb_data;
 101         struct dma_chan *dma_chan;
 102
 103         bool client_ready;
 104         bool qp_link;
 105         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 106
 107         struct ntb_rx_info __iomem *rx_info;
 108         struct ntb_rx_info *remote_rx_info;
 109
 110         void (*tx_handler) (struct ntb_transport_qp *qp, void *qp_data,
 111                             void *data, int len);
 112         struct list_head tx_free_q;
 113         spinlock_t ntb_tx_free_q_lock;
 114         void __iomem *tx_mw;
 115         dma_addr_t tx_mw_phys;
 116         unsigned int tx_index;
 117         unsigned int tx_max_entry;
 118         unsigned int tx_max_frame;
 119
 120         void (*rx_handler) (struct ntb_transport_qp *qp, void *qp_data,
 121                             void *data, int len);
 122         struct tasklet_struct rx_work;
 123         struct list_head rx_pend_q;
 124         struct list_head rx_free_q;
 125         spinlock_t ntb_rx_pend_q_lock;
 126         spinlock_t ntb_rx_free_q_lock;
 127         void *rx_buff;
 128         unsigned int rx_index;
 129         unsigned int rx_max_entry;
 130         unsigned int rx_max_frame;
 131         dma_cookie_t last_cookie;
 132
 133         void (*event_handler) (void *data, int status);
 134         struct delayed_work link_work;
 135         struct work_struct link_cleanup;
 136
 137         struct dentry *debugfs_dir;
 138         struct dentry *debugfs_stats;
 139
 140         /* Stats */
 141         u64 rx_bytes;
 142         u64 rx_pkts;
 143         u64 rx_ring_empty;
 144         u64 rx_err_no_buf;
 145         u64 rx_err_oflow;
 146         u64 rx_err_ver;
 147         u64 rx_memcpy;
 148         u64 rx_async;
 149         u64 tx_bytes;
 150         u64 tx_pkts;
 151         u64 tx_ring_full;
 152         u64 tx_err_no_buf;
 153         u64 tx_memcpy;
 154         u64 tx_async;
 155 };
 156
 157 struct ntb_transport_mw {
 158         size_t size;
 159         void *virt_addr;
 160         dma_addr_t dma_addr;
 161 };
 162
 163 struct ntb_transport_client_dev {
 164         struct list_head entry;
 165         struct device dev;
 166 };
 167
 168 struct ntb_transport {
 169         struct list_head entry;
 170         struct list_head client_devs;
 171
 172         struct ntb_device *ndev;
 173         struct ntb_transport_mw *mw;
 174         struct ntb_transport_qp *qps;
 175         unsigned int max_qps;
 176         unsigned long qp_bitmap;
 177         bool transport_link;
 178         struct delayed_work link_work;
 179         struct work_struct link_cleanup;
 180 };
 181
 182 enum {
 183         DESC_DONE_FLAG = 1 << 0,
 184         LINK_DOWN_FLAG = 1 << 1,
 185 };
 186
 187 struct ntb_payload_header {
 188         unsigned int ver;
 189         unsigned int len;
 190         unsigned int flags;
 191 };
 192
 193 enum {
 194         VERSION = 0,
 195         QP_LINKS,
 196         NUM_QPS,
 197         NUM_MWS,
 198         MW0_SZ_HIGH,
 199         MW0_SZ_LOW,
 200         MW1_SZ_HIGH,
 201         MW1_SZ_LOW,
 202         MAX_SPAD,
 203 };
 204
 205 #define QP_TO_MW(ndev, qp)      ((qp) % ntb_max_mw(ndev))
 206 #define NTB_QP_DEF_NUM_ENTRIES  100
 207 #define NTB_LINK_DOWN_TIMEOUT   10
 208
 209 static int ntb_match_bus(struct device *dev, struct device_driver *drv)
 210 {
 211         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 212 }
 213
 214 static int ntb_client_probe(struct device *dev)
 215 {
 216         const struct ntb_client *drv = container_of(dev->driver,
 217                                                     struct ntb_client, driver);
 218         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 219         int rc = -EINVAL;
 220
 221         get_device(dev);
 222         if (drv && drv->probe)
 223                 rc = drv->probe(pdev);
 224         if (rc)
 225                 put_device(dev);
 226
 227         return rc;
 228 }
 229
 230 static int ntb_client_remove(struct device *dev)
 231 {
 232         const struct ntb_client *drv = container_of(dev->driver,
 233                                                     struct ntb_client, driver);
 234         struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
 235
 236         if (drv && drv->remove)
 237                 drv->remove(pdev);
 238
 239         put_device(dev);
 240
 241         return 0;
 242 }
 243
 244 static struct bus_type ntb_bus_type = {
 245         .name = "ntb_bus",
 246         .match = ntb_match_bus,
 247         .probe = ntb_client_probe,
 248         .remove = ntb_client_remove,
 249 };
 250
 251 static LIST_HEAD(ntb_transport_list);
 252
 253 static int ntb_bus_init(struct ntb_transport *nt)
 254 {
 255         if (list_empty(&ntb_transport_list)) {
 256                 int rc = bus_register(&ntb_bus_type);
 257                 if (rc)
 258                         return rc;
 259         }
 260
 261         list_add(&nt->entry, &ntb_transport_list);
 262
 263         return 0;
 264 }
 265
 266 static void ntb_bus_remove(struct ntb_transport *nt)
 267 {
 268         struct ntb_transport_client_dev *client_dev, *cd;
 269
 270         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 271                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 272                         dev_name(&client_dev->dev));
 273                 list_del(&client_dev->entry);
 274                 device_unregister(&client_dev->dev);
 275         }
 276
 277         list_del(&nt->entry);
 278
 279         if (list_empty(&ntb_transport_list))
 280                 bus_unregister(&ntb_bus_type);
 281 }
 282
 283 static void ntb_client_release(struct device *dev)
 284 {
 285         struct ntb_transport_client_dev *client_dev;
 286         client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
 287
 288         kfree(client_dev);
 289 }
 290
 291 /**
 292  * ntb_unregister_client_dev - Unregister NTB client device
 293  * @device_name: Name of NTB client device
 294  *
 295  * Unregister an NTB client device with the NTB transport layer
 296  */
 297 void ntb_unregister_client_dev(char *device_name)
 298 {
 299         struct ntb_transport_client_dev *client, *cd;
 300         struct ntb_transport *nt;
 301
 302         list_for_each_entry(nt, &ntb_transport_list, entry)
 303                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 304                         if (!strncmp(dev_name(&client->dev), device_name,
 305                                      strlen(device_name))) {
 306                                 list_del(&client->entry);
 307                                 device_unregister(&client->dev);
 308                         }
 309 }
 310 EXPORT_SYMBOL_GPL(ntb_unregister_client_dev);
 311
 312 /**
 313  * ntb_register_client_dev - Register NTB client device
 314  * @device_name: Name of NTB client device
 315  *
 316  * Register an NTB client device with the NTB transport layer
 317  */
 318 int ntb_register_client_dev(char *device_name)
 319 {
 320         struct ntb_transport_client_dev *client_dev;
 321         struct ntb_transport *nt;
 322         int rc, i = 0;
 323
 324         if (list_empty(&ntb_transport_list))
 325                 return -ENODEV;
 326
 327         list_for_each_entry(nt, &ntb_transport_list, entry) {
 328                 struct device *dev;
 329
 330                 client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
 331                                      GFP_KERNEL);
 332                 if (!client_dev) {
 333                         rc = -ENOMEM;
 334                         goto err;
 335                 }
 336
 337                 dev = &client_dev->dev;
 338
 339                 /* setup and register client devices */
 340                 dev_set_name(dev, "%s%d", device_name, i);
 341                 dev->bus = &ntb_bus_type;
 342                 dev->release = ntb_client_release;
 343                 dev->parent = &ntb_query_pdev(nt->ndev)->dev;
 344
 345                 rc = device_register(dev);
 346                 if (rc) {
 347                         kfree(client_dev);
 348                         goto err;
 349                 }
 350
 351                 list_add_tail(&client_dev->entry, &nt->client_devs);
 352                 i++;
 353         }
 354
 355         return 0;
 356
 357 err:
 358         ntb_unregister_client_dev(device_name);
 359
 360         return rc;
 361 }
 362 EXPORT_SYMBOL_GPL(ntb_register_client_dev);
 363
 364 /**
 365  * ntb_register_client - Register NTB client driver
 366  * @drv: NTB client driver to be registered
 367  *
 368  * Register an NTB client driver with the NTB transport layer
 369  *
 370  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 371  */
 372 int ntb_register_client(struct ntb_client *drv)
 373 {
 374         drv->driver.bus = &ntb_bus_type;
 375
 376         if (list_empty(&ntb_transport_list))
 377                 return -ENODEV;
 378
 379         return driver_register(&drv->driver);
 380 }
 381 EXPORT_SYMBOL_GPL(ntb_register_client);
 382
 383 /**
 384  * ntb_unregister_client - Unregister NTB client driver
 385  * @drv: NTB client driver to be unregistered
 386  *
 387  * Unregister an NTB client driver with the NTB transport layer
 388  *
 389  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 390  */
 391 void ntb_unregister_client(struct ntb_client *drv)
 392 {
 393         driver_unregister(&drv->driver);
 394 }
 395 EXPORT_SYMBOL_GPL(ntb_unregister_client);
 396
 397 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 398                             loff_t *offp)
 399 {
 400         struct ntb_transport_qp *qp;
 401         char *buf;
 402         ssize_t ret, out_offset, out_count;
 403
 404         out_count = 1000;
 405
 406         buf = kmalloc(out_count, GFP_KERNEL);
 407         if (!buf)
 408                 return -ENOMEM;
 409
 410         qp = filp->private_data;
 411         out_offset = 0;
 412         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 413                                "NTB QP stats\n");
 414         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 415                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 416         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 417                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 418         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 419                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
 420         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 421                                "rx_async - \t%llu\n", qp->rx_async);
 422         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 423                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 424         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 425                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 426         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 427                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 428         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 429                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 430         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 431                                "rx_buff - \t%p\n", qp->rx_buff);
 432         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 433                                "rx_index - \t%u\n", qp->rx_index);
 434         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 435                                "rx_max_entry - \t%u\n", qp->rx_max_entry);
 436
 437         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 438                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 439         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 440                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 441         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 442                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
 443         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 444                                "tx_async - \t%llu\n", qp->tx_async);
 445         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 446                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 447         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 448                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 449         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 450                                "tx_mw - \t%p\n", qp->tx_mw);
 451         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 452                                "tx_index - \t%u\n", qp->tx_index);
 453         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 454                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
 455
 456         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 457                                "\nQP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
 458                                "Up" : "Down");
 459         if (out_offset > out_count)
 460                 out_offset = out_count;
 461
 462         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 463         kfree(buf);
 464         return ret;
 465 }
 466
 467 static const struct file_operations ntb_qp_debugfs_stats = {
 468         .owner = THIS_MODULE,
 469         .open = simple_open,
 470         .read = debugfs_read,
 471 };
 472
 473 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 474                          struct list_head *list)
 475 {
 476         unsigned long flags;
 477
 478         spin_lock_irqsave(lock, flags);
 479         list_add_tail(entry, list);
 480         spin_unlock_irqrestore(lock, flags);
 481 }
 482
 483 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 484                                                 struct list_head *list)
 485 {
 486         struct ntb_queue_entry *entry;
 487         unsigned long flags;
 488
 489         spin_lock_irqsave(lock, flags);
 490         if (list_empty(list)) {
 491                 entry = NULL;
 492                 goto out;
 493         }
 494         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 495         list_del(&entry->entry);
 496 out:
 497         spin_unlock_irqrestore(lock, flags);
 498
 499         return entry;
 500 }
 501
 502 static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
 503                                       unsigned int qp_num)
 504 {
 505         struct ntb_transport_qp *qp = &nt->qps[qp_num];
 506         unsigned int rx_size, num_qps_mw;
 507         u8 mw_num, mw_max;
 508         unsigned int i;
 509
 510         mw_max = ntb_max_mw(nt->ndev);
 511         mw_num = QP_TO_MW(nt->ndev, qp_num);
 512
 513         WARN_ON(nt->mw[mw_num].virt_addr == NULL);
 514
 515         if (nt->max_qps % mw_max && mw_num < nt->max_qps % mw_max)
 516                 num_qps_mw = nt->max_qps / mw_max + 1;
 517         else
 518                 num_qps_mw = nt->max_qps / mw_max;
 519
 520         rx_size = (unsigned int) nt->mw[mw_num].size / num_qps_mw;
 521         qp->rx_buff = nt->mw[mw_num].virt_addr + qp_num / mw_max * rx_size;
 522         rx_size -= sizeof(struct ntb_rx_info);
 523
 524         qp->remote_rx_info = qp->rx_buff + rx_size;
 525
 526         /* Due to housekeeping, there must be atleast 2 buffs */
 527         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
 528         qp->rx_max_entry = rx_size / qp->rx_max_frame;
 529         qp->rx_index = 0;
 530
 531         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
 532
 533         /* setup the hdr offsets with 0's */
 534         for (i = 0; i < qp->rx_max_entry; i++) {
 535                 void *offset = qp->rx_buff + qp->rx_max_frame * (i + 1) -
 536                                sizeof(struct ntb_payload_header);
 537                 memset(offset, 0, sizeof(struct ntb_payload_header));
 538         }
 539
 540         qp->rx_pkts = 0;
 541         qp->tx_pkts = 0;
 542         qp->tx_index = 0;
 543 }
 544
 545 static void ntb_free_mw(struct ntb_transport *nt, int num_mw)
 546 {
 547         struct ntb_transport_mw *mw = &nt->mw[num_mw];
 548         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 549
 550         if (!mw->virt_addr)
 551                 return;
 552
 553         dma_free_coherent(&pdev->dev, mw->size, mw->virt_addr, mw->dma_addr);
 554         mw->virt_addr = NULL;
 555 }
 556
 557 static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
 558 {
 559         struct ntb_transport_mw *mw = &nt->mw[num_mw];
 560         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 561
 562         /* No need to re-setup */
 563         if (mw->size == ALIGN(size, 4096))
 564                 return 0;
 565
 566         if (mw->size != 0)
 567                 ntb_free_mw(nt, num_mw);
 568
 569         /* Alloc memory for receiving data.  Must be 4k aligned */
 570         mw->size = ALIGN(size, 4096);
 571
 572         mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
 573                                            GFP_KERNEL);
 574         if (!mw->virt_addr) {
 575                 mw->size = 0;
 576                 dev_err(&pdev->dev, "Unable to allocate MW buffer of size %d\n",
 577                        (int) mw->size);
 578                 return -ENOMEM;
 579         }
 580
 581         /* Notify HW the memory location of the receive buffer */
 582         ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
 583
 584         return 0;
 585 }
 586
 587 static void ntb_qp_link_cleanup(struct work_struct *work)
 588 {
 589         struct ntb_transport_qp *qp = container_of(work,
 590                                                    struct ntb_transport_qp,
 591                                                    link_cleanup);
 592         struct ntb_transport *nt = qp->transport;
 593         struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
 594
 595         if (qp->qp_link == NTB_LINK_DOWN) {
 596                 cancel_delayed_work_sync(&qp->link_work);
 597                 return;
 598         }
 599
 600         if (qp->event_handler)
 601                 qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
 602
 603         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
 604         qp->qp_link = NTB_LINK_DOWN;
 605
 606         if (nt->transport_link == NTB_LINK_UP)
 607                 schedule_delayed_work(&qp->link_work,
 608                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 609 }
 610
 611 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 612 {
 613         schedule_work(&qp->link_cleanup);
 614 }
 615
 616 static void ntb_transport_link_cleanup(struct work_struct *work)
 617 {
 618         struct ntb_transport *nt = container_of(work, struct ntb_transport,
 619                                                 link_cleanup);
 620         int i;
 621
 622         if (nt->transport_link == NTB_LINK_DOWN)
 623                 cancel_delayed_work_sync(&nt->link_work);
 624         else
 625                 nt->transport_link = NTB_LINK_DOWN;
 626
 627         /* Pass along the info to any clients */
 628         for (i = 0; i < nt->max_qps; i++)
 629                 if (!test_bit(i, &nt->qp_bitmap))
 630                         ntb_qp_link_down(&nt->qps[i]);
 631
 632         /* The scratchpad registers keep the values if the remote side
 633          * goes down, blast them now to give them a sane value the next
 634          * time they are accessed
 635          */
 636         for (i = 0; i < MAX_SPAD; i++)
 637                 ntb_write_local_spad(nt->ndev, i, 0);
 638 }
 639
 640 static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
 641 {
 642         struct ntb_transport *nt = data;
 643
 644         switch (event) {
 645         case NTB_EVENT_HW_LINK_UP:
 646                 schedule_delayed_work(&nt->link_work, 0);
 647                 break;
 648         case NTB_EVENT_HW_LINK_DOWN:
 649                 schedule_work(&nt->link_cleanup);
 650                 break;
 651         default:
 652                 BUG();
 653         }
 654 }
 655
 656 static void ntb_transport_link_work(struct work_struct *work)
 657 {
 658         struct ntb_transport *nt = container_of(work, struct ntb_transport,
 659                                                 link_work.work);
 660         struct ntb_device *ndev = nt->ndev;
 661         struct pci_dev *pdev = ntb_query_pdev(ndev);
 662         u32 val;
 663         int rc, i;
 664
 665         /* send the local info, in the opposite order of the way we read it */
 666         for (i = 0; i < ntb_max_mw(ndev); i++) {
 667                 rc = ntb_write_remote_spad(ndev, MW0_SZ_HIGH + (i * 2),
 668                                            ntb_get_mw_size(ndev, i) >> 32);
 669                 if (rc) {
 670                         dev_err(&pdev->dev, "Error writing %u to remote spad %d\n",
 671                                 (u32)(ntb_get_mw_size(ndev, i) >> 32),
 672                                 MW0_SZ_HIGH + (i * 2));
 673                         goto out;
 674                 }
 675
 676                 rc = ntb_write_remote_spad(ndev, MW0_SZ_LOW + (i * 2),
 677                                            (u32) ntb_get_mw_size(ndev, i));
 678                 if (rc) {
 679                         dev_err(&pdev->dev, "Error writing %u to remote spad %d\n",
 680                                 (u32) ntb_get_mw_size(ndev, i),
 681                                 MW0_SZ_LOW + (i * 2));
 682                         goto out;
 683                 }
 684         }
 685
 686         rc = ntb_write_remote_spad(ndev, NUM_MWS, ntb_max_mw(ndev));
 687         if (rc) {
 688                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 689                         ntb_max_mw(ndev), NUM_MWS);
 690                 goto out;
 691         }
 692
 693         rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
 694         if (rc) {
 695                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 696                         nt->max_qps, NUM_QPS);
 697                 goto out;
 698         }
 699
 700         rc = ntb_write_remote_spad(ndev, VERSION, NTB_TRANSPORT_VERSION);
 701         if (rc) {
 702                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 703                         NTB_TRANSPORT_VERSION, VERSION);
 704                 goto out;
 705         }
 706
 707         /* Query the remote side for its info */
 708         rc = ntb_read_remote_spad(ndev, VERSION, &val);
 709         if (rc) {
 710                 dev_err(&pdev->dev, "Error reading remote spad %d\n", VERSION);
 711                 goto out;
 712         }
 713
 714         if (val != NTB_TRANSPORT_VERSION)
 715                 goto out;
 716         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 717
 718         rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
 719         if (rc) {
 720                 dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
 721                 goto out;
 722         }
 723
 724         if (val != nt->max_qps)
 725                 goto out;
 726         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 727
 728         rc = ntb_read_remote_spad(ndev, NUM_MWS, &val);
 729         if (rc) {
 730                 dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_MWS);
 731                 goto out;
 732         }
 733
 734         if (val != ntb_max_mw(ndev))
 735                 goto out;
 736         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
 737
 738         for (i = 0; i < ntb_max_mw(ndev); i++) {
 739                 u64 val64;
 740
 741                 rc = ntb_read_remote_spad(ndev, MW0_SZ_HIGH + (i * 2), &val);
 742                 if (rc) {
 743                         dev_err(&pdev->dev, "Error reading remote spad %d\n",
 744                                 MW0_SZ_HIGH + (i * 2));
 745                         goto out1;
 746                 }
 747
 748                 val64 = (u64) val << 32;
 749
 750                 rc = ntb_read_remote_spad(ndev, MW0_SZ_LOW + (i * 2), &val);
 751                 if (rc) {
 752                         dev_err(&pdev->dev, "Error reading remote spad %d\n",
 753                                 MW0_SZ_LOW + (i * 2));
 754                         goto out1;
 755                 }
 756
 757                 val64 |= val;
 758
 759                 dev_dbg(&pdev->dev, "Remote MW%d size = %llu\n", i, val64);
 760
 761                 rc = ntb_set_mw(nt, i, val64);
 762                 if (rc)
 763                         goto out1;
 764         }
 765
 766         nt->transport_link = NTB_LINK_UP;
 767
 768         for (i = 0; i < nt->max_qps; i++) {
 769                 struct ntb_transport_qp *qp = &nt->qps[i];
 770
 771                 ntb_transport_setup_qp_mw(nt, i);
 772
 773                 if (qp->client_ready == NTB_LINK_UP)
 774                         schedule_delayed_work(&qp->link_work, 0);
 775         }
 776
 777         return;
 778
 779 out1:
 780         for (i = 0; i < ntb_max_mw(ndev); i++)
 781                 ntb_free_mw(nt, i);
 782 out:
 783         if (ntb_hw_link_status(ndev))
 784                 schedule_delayed_work(&nt->link_work,
 785                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 786 }
 787
 788 static void ntb_qp_link_work(struct work_struct *work)
 789 {
 790         struct ntb_transport_qp *qp = container_of(work,
 791                                                    struct ntb_transport_qp,
 792                                                    link_work.work);
 793         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
 794         struct ntb_transport *nt = qp->transport;
 795         int rc, val;
 796
 797         WARN_ON(nt->transport_link != NTB_LINK_UP);
 798
 799         rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
 800         if (rc) {
 801                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
 802                 return;
 803         }
 804
 805         rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
 806         if (rc)
 807                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
 808                         val | 1 << qp->qp_num, QP_LINKS);
 809
 810         /* query remote spad for qp ready bits */
 811         rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
 812         if (rc)
 813                 dev_err(&pdev->dev, "Error reading remote spad %d\n", QP_LINKS);
 814
 815         dev_dbg(&pdev->dev, "Remote QP link status = %x\n", val);
 816
 817         /* See if the remote side is up */
 818         if (1 << qp->qp_num & val) {
 819                 qp->qp_link = NTB_LINK_UP;
 820
 821                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 822                 if (qp->event_handler)
 823                         qp->event_handler(qp->cb_data, NTB_LINK_UP);
 824         } else if (nt->transport_link == NTB_LINK_UP)
 825                 schedule_delayed_work(&qp->link_work,
 826                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 827 }
 828
 829 static int ntb_transport_init_queue(struct ntb_transport *nt,
 830                                      unsigned int qp_num)
 831 {
 832         struct ntb_transport_qp *qp;
 833         unsigned int num_qps_mw, tx_size;
 834         u8 mw_num, mw_max;
 835         u64 qp_offset;
 836
 837         mw_max = ntb_max_mw(nt->ndev);
 838         mw_num = QP_TO_MW(nt->ndev, qp_num);
 839
 840         qp = &nt->qps[qp_num];
 841         qp->qp_num = qp_num;
 842         qp->transport = nt;
 843         qp->ndev = nt->ndev;
 844         qp->qp_link = NTB_LINK_DOWN;
 845         qp->client_ready = NTB_LINK_DOWN;
 846         qp->event_handler = NULL;
 847
 848         if (nt->max_qps % mw_max && mw_num < nt->max_qps % mw_max)
 849                 num_qps_mw = nt->max_qps / mw_max + 1;
 850         else
 851                 num_qps_mw = nt->max_qps / mw_max;
 852
 853         tx_size = (unsigned int) ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw;
 854         qp_offset = qp_num / mw_max * tx_size;
 855         qp->tx_mw = ntb_get_mw_vbase(nt->ndev, mw_num) + qp_offset;
 856         if (!qp->tx_mw)
 857                 return -EINVAL;
 858
 859         qp->tx_mw_phys = ntb_get_mw_base(qp->ndev, mw_num) + qp_offset;
 860         if (!qp->tx_mw_phys)
 861                 return -EINVAL;
 862
 863         tx_size -= sizeof(struct ntb_rx_info);
 864         qp->rx_info = qp->tx_mw + tx_size;
 865
 866         /* Due to housekeeping, there must be atleast 2 buffs */
 867         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 868         qp->tx_max_entry = tx_size / qp->tx_max_frame;
 869
 870         if (ntb_query_debugfs(nt->ndev)) {
 871                 char debugfs_name[4];
 872
 873                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 874                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 875                                                  ntb_query_debugfs(nt->ndev));
 876
 877                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 878                                                         qp->debugfs_dir, qp,
 879                                                         &ntb_qp_debugfs_stats);
 880         }
 881
 882         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 883         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup);
 884
 885         spin_lock_init(&qp->ntb_rx_pend_q_lock);
 886         spin_lock_init(&qp->ntb_rx_free_q_lock);
 887         spin_lock_init(&qp->ntb_tx_free_q_lock);
 888
 889         INIT_LIST_HEAD(&qp->rx_pend_q);
 890         INIT_LIST_HEAD(&qp->rx_free_q);
 891         INIT_LIST_HEAD(&qp->tx_free_q);
 892
 893         return 0;
 894 }
 895
 896 int ntb_transport_init(struct pci_dev *pdev)
 897 {
 898         struct ntb_transport *nt;
 899         int rc, i;
 900
 901         nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
 902         if (!nt)
 903                 return -ENOMEM;
 904
 905         nt->ndev = ntb_register_transport(pdev, nt);
 906         if (!nt->ndev) {
 907                 rc = -EIO;
 908                 goto err;
 909         }
 910
 911         nt->mw = kcalloc(ntb_max_mw(nt->ndev), sizeof(struct ntb_transport_mw),
 912                          GFP_KERNEL);
 913         if (!nt->mw) {
 914                 rc = -ENOMEM;
 915                 goto err1;
 916         }
 917
 918         if (max_num_clients)
 919                 nt->max_qps = min(ntb_max_cbs(nt->ndev), max_num_clients);
 920         else
 921                 nt->max_qps = min(ntb_max_cbs(nt->ndev), ntb_max_mw(nt->ndev));
 922
 923         nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
 924                           GFP_KERNEL);
 925         if (!nt->qps) {
 926                 rc = -ENOMEM;
 927                 goto err2;
 928         }
 929
 930         nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
 931
 932         for (i = 0; i < nt->max_qps; i++) {
 933                 rc = ntb_transport_init_queue(nt, i);
 934                 if (rc)
 935                         goto err3;
 936         }
 937
 938         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
 939         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup);
 940
 941         rc = ntb_register_event_callback(nt->ndev,
 942                                          ntb_transport_event_callback);
 943         if (rc)
 944                 goto err3;
 945
 946         INIT_LIST_HEAD(&nt->client_devs);
 947         rc = ntb_bus_init(nt);
 948         if (rc)
 949                 goto err4;
 950
 951         if (ntb_hw_link_status(nt->ndev))
 952                 schedule_delayed_work(&nt->link_work, 0);
 953
 954         return 0;
 955
 956 err4:
 957         ntb_unregister_event_callback(nt->ndev);
 958 err3:
 959         kfree(nt->qps);
 960 err2:
 961         kfree(nt->mw);
 962 err1:
 963         ntb_unregister_transport(nt->ndev);
 964 err:
 965         kfree(nt);
 966         return rc;
 967 }
 968
 969 void ntb_transport_free(void *transport)
 970 {
 971         struct ntb_transport *nt = transport;
 972         struct ntb_device *ndev = nt->ndev;
 973         int i;
 974
 975         nt->transport_link = NTB_LINK_DOWN;
 976
 977         /* verify that all the qp's are freed */
 978         for (i = 0; i < nt->max_qps; i++) {
 979                 if (!test_bit(i, &nt->qp_bitmap))
 980                         ntb_transport_free_queue(&nt->qps[i]);
 981                 debugfs_remove_recursive(nt->qps[i].debugfs_dir);
 982         }
 983
 984         ntb_bus_remove(nt);
 985
 986         cancel_delayed_work_sync(&nt->link_work);
 987
 988         ntb_unregister_event_callback(ndev);
 989
 990         for (i = 0; i < ntb_max_mw(ndev); i++)
 991                 ntb_free_mw(nt, i);
 992
 993         kfree(nt->qps);
 994         kfree(nt->mw);
 995         ntb_unregister_transport(ndev);
 996         kfree(nt);
 997 }
 998
 999 static void ntb_rx_copy_callback(void *data)
1000 {
1001         struct ntb_queue_entry *entry = data;
1002         struct ntb_transport_qp *qp = entry->qp;
1003         void *cb_data = entry->cb_data;
1004         unsigned int len = entry->len;
1005         struct ntb_payload_header *hdr = entry->rx_hdr;
1006
1007         /* Ensure that the data is fully copied out before clearing the flag */
1008         wmb();
1009         hdr->flags = 0;
1010
1011         iowrite32(entry->index, &qp->rx_info->entry);
1012
1013         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1014
1015         if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
1016                 qp->rx_handler(qp, qp->cb_data, cb_data, len);
1017 }
1018
1019 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1020 {
1021         void *buf = entry->buf;
1022         size_t len = entry->len;
1023
1024         memcpy(buf, offset, len);
1025
1026         ntb_rx_copy_callback(entry);
1027 }
1028
1029 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
1030                          size_t len)
1031 {
1032         struct dma_async_tx_descriptor *txd;
1033         struct ntb_transport_qp *qp = entry->qp;
1034         struct dma_chan *chan = qp->dma_chan;
1035         struct dma_device *device;
1036         size_t pay_off, buff_off;
1037         dma_addr_t src, dest;
1038         dma_cookie_t cookie;
1039         void *buf = entry->buf;
1040         unsigned long flags;
1041
1042         entry->len = len;
1043
1044         if (!chan)
1045                 goto err;
1046
1047         if (len < copy_bytes)
1048                 goto err1;
1049
1050         device = chan->device;
1051         pay_off = (size_t) offset & ~PAGE_MASK;
1052         buff_off = (size_t) buf & ~PAGE_MASK;
1053
1054         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1055                 goto err1;
1056
1057         dest = dma_map_single(device->dev, buf, len, DMA_FROM_DEVICE);
1058         if (dma_mapping_error(device->dev, dest))
1059                 goto err1;
1060
1061         src = dma_map_single(device->dev, offset, len, DMA_TO_DEVICE);
1062         if (dma_mapping_error(device->dev, src))
1063                 goto err2;
1064
1065         flags = DMA_COMPL_DEST_UNMAP_SINGLE | DMA_COMPL_SRC_UNMAP_SINGLE |
1066                 DMA_PREP_INTERRUPT;
1067         txd = device->device_prep_dma_memcpy(chan, dest, src, len, flags);
1068         if (!txd)
1069                 goto err3;
1070
1071         txd->callback = ntb_rx_copy_callback;
1072         txd->callback_param = entry;
1073
1074         cookie = dmaengine_submit(txd);
1075         if (dma_submit_error(cookie))
1076                 goto err3;
1077
1078         qp->last_cookie = cookie;
1079
1080         qp->rx_async++;
1081
1082         return;
1083
1084 err3:
1085         dma_unmap_single(device->dev, src, len, DMA_TO_DEVICE);
1086 err2:
1087         dma_unmap_single(device->dev, dest, len, DMA_FROM_DEVICE);
1088 err1:
1089         /* If the callbacks come out of order, the writing of the index to the
1090          * last completed will be out of order.  This may result in the
1091          * receive stalling forever.
1092          */
1093         dma_sync_wait(chan, qp->last_cookie);
1094 err:
1095         ntb_memcpy_rx(entry, offset);
1096         qp->rx_memcpy++;
1097 }
1098
1099 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1100 {
1101         struct ntb_payload_header *hdr;
1102         struct ntb_queue_entry *entry;
1103         void *offset;
1104
1105         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1106         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1107
1108         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1109         if (!entry) {
1110                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
1111                         "no buffer - HDR ver %u, len %d, flags %x\n",
1112                         hdr->ver, hdr->len, hdr->flags);
1113                 qp->rx_err_no_buf++;
1114                 return -ENOMEM;
1115         }
1116
1117         if (!(hdr->flags & DESC_DONE_FLAG)) {
1118                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
1119                              &qp->rx_pend_q);
1120                 qp->rx_ring_empty++;
1121                 return -EAGAIN;
1122         }
1123
1124         if (hdr->ver != (u32) qp->rx_pkts) {
1125                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
1126                         "qp %d: version mismatch, expected %llu - got %u\n",
1127                         qp->qp_num, qp->rx_pkts, hdr->ver);
1128                 ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
1129                              &qp->rx_pend_q);
1130                 qp->rx_err_ver++;
1131                 return -EIO;
1132         }
1133
1134         if (hdr->flags & LINK_DOWN_FLAG) {
1135                 ntb_qp_link_down(qp);
1136
1137                 goto err;
1138         }
1139
1140         dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
1141                 "rx offset %u, ver %u - %d payload received, buf size %d\n",
1142                 qp->rx_index, hdr->ver, hdr->len, entry->len);
1143
1144         qp->rx_bytes += hdr->len;
1145         qp->rx_pkts++;
1146
1147         if (hdr->len > entry->len) {
1148                 qp->rx_err_oflow++;
1149                 dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
1150                         "RX overflow! Wanted %d got %d\n",
1151                         hdr->len, entry->len);
1152
1153                 goto err;
1154         }
1155
1156         entry->index = qp->rx_index;
1157         entry->rx_hdr = hdr;
1158
1159         ntb_async_rx(entry, offset, hdr->len);
1160
1161 out:
1162         qp->rx_index++;
1163         qp->rx_index %= qp->rx_max_entry;
1164
1165         return 0;
1166
1167 err:
1168         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
1169                      &qp->rx_pend_q);
1170         /* Ensure that the data is fully copied out before clearing the flag */
1171         wmb();
1172         hdr->flags = 0;
1173         iowrite32(qp->rx_index, &qp->rx_info->entry);
1174
1175         goto out;
1176 }
1177
1178 static void ntb_transport_rx(unsigned long data)
1179 {
1180         struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
1181         int rc, i;
1182
1183         /* Limit the number of packets processed in a single interrupt to
1184          * provide fairness to others
1185          */
1186         for (i = 0; i < qp->rx_max_entry; i++) {
1187                 rc = ntb_process_rxc(qp);
1188                 if (rc)
1189                         break;
1190         }
1191
1192         if (qp->dma_chan)
1193                 dma_async_issue_pending(qp->dma_chan);
1194 }
1195
1196 static void ntb_transport_rxc_db(void *data, int db_num)
1197 {
1198         struct ntb_transport_qp *qp = data;
1199
1200         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
1201                 __func__, db_num);
1202
1203         tasklet_schedule(&qp->rx_work);
1204 }
1205
1206 static void ntb_tx_copy_callback(void *data)
1207 {
1208         struct ntb_queue_entry *entry = data;
1209         struct ntb_transport_qp *qp = entry->qp;
1210         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1211
1212         /* Ensure that the data is fully copied out before setting the flags */
1213         wmb();
1214         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1215
1216         ntb_ring_doorbell(qp->ndev, qp->qp_num);
1217
1218         /* The entry length can only be zero if the packet is intended to be a
1219          * "link down" or similar.  Since no payload is being sent in these
1220          * cases, there is nothing to add to the completion queue.
1221          */
1222         if (entry->len > 0) {
1223                 qp->tx_bytes += entry->len;
1224
1225                 if (qp->tx_handler)
1226                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1227                                        entry->len);
1228         }
1229
1230         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1231 }
1232
1233 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1234 {
1235         memcpy_toio(offset, entry->buf, entry->len);
1236
1237         ntb_tx_copy_callback(entry);
1238 }
1239
1240 static void ntb_async_tx(struct ntb_transport_qp *qp,
1241                          struct ntb_queue_entry *entry)
1242 {
1243         struct ntb_payload_header __iomem *hdr;
1244         struct dma_async_tx_descriptor *txd;
1245         struct dma_chan *chan = qp->dma_chan;
1246         struct dma_device *device;
1247         size_t dest_off, buff_off;
1248         dma_addr_t src, dest;
1249         dma_cookie_t cookie;
1250         void __iomem *offset;
1251         size_t len = entry->len;
1252         void *buf = entry->buf;
1253         unsigned long flags;
1254
1255         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1256         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1257         entry->tx_hdr = hdr;
1258
1259         iowrite32(entry->len, &hdr->len);
1260         iowrite32((u32) qp->tx_pkts, &hdr->ver);
1261
1262         if (!chan)
1263                 goto err;
1264
1265         if (len < copy_bytes)
1266                 goto err;
1267
1268         device = chan->device;
1269         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1270         buff_off = (size_t) buf & ~PAGE_MASK;
1271         dest_off = (size_t) dest & ~PAGE_MASK;
1272
1273         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1274                 goto err;
1275
1276         src = dma_map_single(device->dev, buf, len, DMA_TO_DEVICE);
1277         if (dma_mapping_error(device->dev, src))
1278                 goto err;
1279
1280         flags = DMA_COMPL_SRC_UNMAP_SINGLE | DMA_PREP_INTERRUPT;
1281         txd = device->device_prep_dma_memcpy(chan, dest, src, len, flags);
1282         if (!txd)
1283                 goto err1;
1284
1285         txd->callback = ntb_tx_copy_callback;
1286         txd->callback_param = entry;
1287
1288         cookie = dmaengine_submit(txd);
1289         if (dma_submit_error(cookie))
1290                 goto err1;
1291
1292         dma_async_issue_pending(chan);
1293         qp->tx_async++;
1294
1295         return;
1296 err1:
1297         dma_unmap_single(device->dev, src, len, DMA_TO_DEVICE);
1298 err:
1299         ntb_memcpy_tx(entry, offset);
1300         qp->tx_memcpy++;
1301 }
1302
1303 static int ntb_process_tx(struct ntb_transport_qp *qp,
1304                           struct ntb_queue_entry *entry)
1305 {
1306         dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - tx %u, entry len %d flags %x buff %p\n",
1307                 qp->tx_pkts, qp->tx_index, entry->len, entry->flags,
1308                 entry->buf);
1309         if (qp->tx_index == qp->remote_rx_info->entry) {
1310                 qp->tx_ring_full++;
1311                 return -EAGAIN;
1312         }
1313
1314         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1315                 if (qp->tx_handler)
1316                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1317
1318                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1319                              &qp->tx_free_q);
1320                 return 0;
1321         }
1322
1323         ntb_async_tx(qp, entry);
1324
1325         qp->tx_index++;
1326         qp->tx_index %= qp->tx_max_entry;
1327
1328         qp->tx_pkts++;
1329
1330         return 0;
1331 }
1332
1333 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1334 {
1335         struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
1336         struct ntb_queue_entry *entry;
1337         int i, rc;
1338
1339         if (qp->qp_link == NTB_LINK_DOWN)
1340                 return;
1341
1342         qp->qp_link = NTB_LINK_DOWN;
1343         dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
1344
1345         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1346                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1347                 if (entry)
1348                         break;
1349                 msleep(100);
1350         }
1351
1352         if (!entry)
1353                 return;
1354
1355         entry->cb_data = NULL;
1356         entry->buf = NULL;
1357         entry->len = 0;
1358         entry->flags = LINK_DOWN_FLAG;
1359
1360         rc = ntb_process_tx(qp, entry);
1361         if (rc)
1362                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1363                         qp->qp_num);
1364 }
1365
1366 /**
1367  * ntb_transport_create_queue - Create a new NTB transport layer queue
1368  * @rx_handler: receive callback function
1369  * @tx_handler: transmit callback function
1370  * @event_handler: event callback function
1371  *
1372  * Create a new NTB transport layer queue and provide the queue with a callback
1373  * routine for both transmit and receive.  The receive callback routine will be
1374  * used to pass up data when the transport has received it on the queue.   The
1375  * transmit callback routine will be called when the transport has completed the
1376  * transmission of the data on the queue and the data is ready to be freed.
1377  *
1378  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1379  */
1380 struct ntb_transport_qp *
1381 ntb_transport_create_queue(void *data, struct pci_dev *pdev,
1382                            const struct ntb_queue_handlers *handlers)
1383 {
1384         struct ntb_queue_entry *entry;
1385         struct ntb_transport_qp *qp;
1386         struct ntb_transport *nt;
1387         unsigned int free_queue;
1388         int rc, i;
1389
1390         nt = ntb_find_transport(pdev);
1391         if (!nt)
1392                 goto err;
1393
1394         free_queue = ffs(nt->qp_bitmap);
1395         if (!free_queue)
1396                 goto err;
1397
1398         /* decrement free_queue to make it zero based */
1399         free_queue--;
1400
1401         clear_bit(free_queue, &nt->qp_bitmap);
1402
1403         qp = &nt->qps[free_queue];
1404         qp->cb_data = data;
1405         qp->rx_handler = handlers->rx_handler;
1406         qp->tx_handler = handlers->tx_handler;
1407         qp->event_handler = handlers->event_handler;
1408
1409         qp->dma_chan = dma_find_channel(DMA_MEMCPY);
1410         if (!qp->dma_chan)
1411                 dev_info(&pdev->dev, "Unable to allocate DMA channel, using CPU instead\n");
1412         else
1413                 dmaengine_get();
1414
1415         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1416                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1417                 if (!entry)
1418                         goto err1;
1419
1420                 entry->qp = qp;
1421                 ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1422                              &qp->rx_free_q);
1423         }
1424
1425         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1426                 entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
1427                 if (!entry)
1428                         goto err2;
1429
1430                 entry->qp = qp;
1431                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1432                              &qp->tx_free_q);
1433         }
1434
1435         tasklet_init(&qp->rx_work, ntb_transport_rx, (unsigned long) qp);
1436
1437         rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
1438                                       ntb_transport_rxc_db);
1439         if (rc)
1440                 goto err3;
1441
1442         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1443
1444         return qp;
1445
1446 err3:
1447         tasklet_disable(&qp->rx_work);
1448 err2:
1449         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1450                 kfree(entry);
1451 err1:
1452         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1453                 kfree(entry);
1454         set_bit(free_queue, &nt->qp_bitmap);
1455 err:
1456         return NULL;
1457 }
1458 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1459
1460 /**
1461  * ntb_transport_free_queue - Frees NTB transport queue
1462  * @qp: NTB queue to be freed
1463  *
1464  * Frees NTB transport queue
1465  */
1466 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1467 {
1468         struct pci_dev *pdev;
1469         struct ntb_queue_entry *entry;
1470
1471         if (!qp)
1472                 return;
1473
1474         pdev = ntb_query_pdev(qp->ndev);
1475
1476         if (qp->dma_chan) {
1477                 struct dma_chan *chan = qp->dma_chan;
1478                 /* Putting the dma_chan to NULL will force any new traffic to be
1479                  * processed by the CPU instead of the DAM engine
1480                  */
1481                 qp->dma_chan = NULL;
1482
1483                 /* Try to be nice and wait for any queued DMA engine
1484                  * transactions to process before smashing it with a rock
1485                  */
1486                 dma_sync_wait(chan, qp->last_cookie);
1487                 dmaengine_terminate_all(chan);
1488                 dmaengine_put();
1489         }
1490
1491         ntb_unregister_db_callback(qp->ndev, qp->qp_num);
1492         tasklet_disable(&qp->rx_work);
1493
1494         cancel_delayed_work_sync(&qp->link_work);
1495
1496         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1497                 kfree(entry);
1498
1499         while ((entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
1500                 dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
1501                 kfree(entry);
1502         }
1503
1504         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1505                 kfree(entry);
1506
1507         set_bit(qp->qp_num, &qp->transport->qp_bitmap);
1508
1509         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1510 }
1511 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1512
1513 /**
1514  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1515  * @qp: NTB queue to be freed
1516  * @len: pointer to variable to write enqueued buffers length
1517  *
1518  * Dequeues unused buffers from receive queue.  Should only be used during
1519  * shutdown of qp.
1520  *
1521  * RETURNS: NULL error value on error, or void* for success.
1522  */
1523 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1524 {
1525         struct ntb_queue_entry *entry;
1526         void *buf;
1527
1528         if (!qp || qp->client_ready == NTB_LINK_UP)
1529                 return NULL;
1530
1531         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1532         if (!entry)
1533                 return NULL;
1534
1535         buf = entry->cb_data;
1536         *len = entry->len;
1537
1538         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1539
1540         return buf;
1541 }
1542 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1543
1544 /**
1545  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1546  * @qp: NTB transport layer queue the entry is to be enqueued on
1547  * @cb: per buffer pointer for callback function to use
1548  * @data: pointer to data buffer that incoming packets will be copied into
1549  * @len: length of the data buffer
1550  *
1551  * Enqueue a new receive buffer onto the transport queue into which a NTB
1552  * payload can be received into.
1553  *
1554  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1555  */
1556 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1557                              unsigned int len)
1558 {
1559         struct ntb_queue_entry *entry;
1560
1561         if (!qp)
1562                 return -EINVAL;
1563
1564         entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
1565         if (!entry)
1566                 return -ENOMEM;
1567
1568         entry->cb_data = cb;
1569         entry->buf = data;
1570         entry->len = len;
1571
1572         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
1573
1574         return 0;
1575 }
1576 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1577
1578 /**
1579  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1580  * @qp: NTB transport layer queue the entry is to be enqueued on
1581  * @cb: per buffer pointer for callback function to use
1582  * @data: pointer to data buffer that will be sent
1583  * @len: length of the data buffer
1584  *
1585  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1586  * payload will be transmitted.  This assumes that a lock is being held to
1587  * serialize access to the qp.
1588  *
1589  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1590  */
1591 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1592                              unsigned int len)
1593 {
1594         struct ntb_queue_entry *entry;
1595         int rc;
1596
1597         if (!qp || qp->qp_link != NTB_LINK_UP || !len)
1598                 return -EINVAL;
1599
1600         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1601         if (!entry) {
1602                 qp->tx_err_no_buf++;
1603                 return -ENOMEM;
1604         }
1605
1606         entry->cb_data = cb;
1607         entry->buf = data;
1608         entry->len = len;
1609         entry->flags = 0;
1610
1611         rc = ntb_process_tx(qp, entry);
1612         if (rc)
1613                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1614                              &qp->tx_free_q);
1615
1616         return rc;
1617 }
1618 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1619
1620 /**
1621  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1622  * @qp: NTB transport layer queue to be enabled
1623  *
1624  * Notify NTB transport layer of client readiness to use queue
1625  */
1626 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1627 {
1628         if (!qp)
1629                 return;
1630
1631         qp->client_ready = NTB_LINK_UP;
1632
1633         if (qp->transport->transport_link == NTB_LINK_UP)
1634                 schedule_delayed_work(&qp->link_work, 0);
1635 }
1636 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1637
1638 /**
1639  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1640  * @qp: NTB transport layer queue to be disabled
1641  *
1642  * Notify NTB transport layer of client's desire to no longer receive data on
1643  * transport queue specified.  It is the client's responsibility to ensure all
1644  * entries on queue are purged or otherwise handled appropriately.
1645  */
1646 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1647 {
1648         struct pci_dev *pdev;
1649         int rc, val;
1650
1651         if (!qp)
1652                 return;
1653
1654         pdev = ntb_query_pdev(qp->ndev);
1655         qp->client_ready = NTB_LINK_DOWN;
1656
1657         rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
1658         if (rc) {
1659                 dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
1660                 return;
1661         }
1662
1663         rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
1664                                    val & ~(1 << qp->qp_num));
1665         if (rc)
1666                 dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
1667                         val & ~(1 << qp->qp_num), QP_LINKS);
1668
1669         if (qp->qp_link == NTB_LINK_UP)
1670                 ntb_send_link_down(qp);
1671         else
1672                 cancel_delayed_work_sync(&qp->link_work);
1673 }
1674 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1675
1676 /**
1677  * ntb_transport_link_query - Query transport link state
1678  * @qp: NTB transport layer queue to be queried
1679  *
1680  * Query connectivity to the remote system of the NTB transport queue
1681  *
1682  * RETURNS: true for link up or false for link down
1683  */
1684 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1685 {
1686         if (!qp)
1687                 return false;
1688
1689         return qp->qp_link == NTB_LINK_UP;
1690 }
1691 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1692
1693 /**
1694  * ntb_transport_qp_num - Query the qp number
1695  * @qp: NTB transport layer queue to be queried
1696  *
1697  * Query qp number of the NTB transport queue
1698  *
1699  * RETURNS: a zero based number specifying the qp number
1700  */
1701 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1702 {
1703         if (!qp)
1704                 return 0;
1705
1706         return qp->qp_num;
1707 }
1708 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1709
1710 /**
1711  * ntb_transport_max_size - Query the max payload size of a qp
1712  * @qp: NTB transport layer queue to be queried
1713  *
1714  * Query the maximum payload size permissible on the given qp
1715  *
1716  * RETURNS: the max payload size of a qp
1717  */
1718 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1719 {
1720         unsigned int max;
1721
1722         if (!qp)
1723                 return 0;
1724
1725         if (!qp->dma_chan)
1726                 return qp->tx_max_frame - sizeof(struct ntb_payload_header);
1727
1728         /* If DMA engine usage is possible, try to find the max size for that */
1729         max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
1730         max -= max % (1 << qp->dma_chan->device->copy_align);
1731
1732         return max;
1733 }
1734 EXPORT_SYMBOL_GPL(ntb_transport_max_size);