kernel/drivers/ntb/ntb_transport.c

   1 /*
   2  * This file is provided under a dual BSD/GPLv2 license.  When using or
   3  *   redistributing this file, you may do so under either license.
   4  *
   5  *   GPL LICENSE SUMMARY
   6  *
   7  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
   8  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
   9  *
  10  *   This program is free software; you can redistribute it and/or modify
  11  *   it under the terms of version 2 of the GNU General Public License as
  12  *   published by the Free Software Foundation.
  13  *
  14  *   BSD LICENSE
  15  *
  16  *   Copyright(c) 2012 Intel Corporation. All rights reserved.
  17  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
  18  *
  19  *   Redistribution and use in source and binary forms, with or without
  20  *   modification, are permitted provided that the following conditions
  21  *   are met:
  22  *
  23  *     * Redistributions of source code must retain the above copyright
  24  *       notice, this list of conditions and the following disclaimer.
  25  *     * Redistributions in binary form must reproduce the above copy
  26  *       notice, this list of conditions and the following disclaimer in
  27  *       the documentation and/or other materials provided with the
  28  *       distribution.
  29  *     * Neither the name of Intel Corporation nor the names of its
  30  *       contributors may be used to endorse or promote products derived
  31  *       from this software without specific prior written permission.
  32  *
  33  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  34  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  35  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  36  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  37  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  38  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  39  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  40  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  41  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  42  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  43  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  44  *
  45  * PCIe NTB Transport Linux driver
  46  *
  47  * Contact Information:
  48  * Jon Mason <jon.mason@intel.com>
  49  */
  50 #include <linux/debugfs.h>
  51 #include <linux/delay.h>
  52 #include <linux/dmaengine.h>
  53 #include <linux/dma-mapping.h>
  54 #include <linux/errno.h>
  55 #include <linux/export.h>
  56 #include <linux/interrupt.h>
  57 #include <linux/module.h>
  58 #include <linux/pci.h>
  59 #include <linux/slab.h>
  60 #include <linux/types.h>
  61 #include <linux/uaccess.h>
  62 #include "linux/ntb.h"
  63 #include "linux/ntb_transport.h"
  64
  65 #define NTB_TRANSPORT_VERSION   4
  66 #define NTB_TRANSPORT_VER       "4"
  67 #define NTB_TRANSPORT_NAME      "ntb_transport"
  68 #define NTB_TRANSPORT_DESC      "Software Queue-Pair Transport over NTB"
  69
  70 MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
  71 MODULE_VERSION(NTB_TRANSPORT_VER);
  72 MODULE_LICENSE("Dual BSD/GPL");
  73 MODULE_AUTHOR("Intel Corporation");
  74
  75 static unsigned long max_mw_size;
  76 module_param(max_mw_size, ulong, 0644);
  77 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
  78
  79 static unsigned int transport_mtu = 0x10000;
  80 module_param(transport_mtu, uint, 0644);
  81 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
  82
  83 static unsigned char max_num_clients;
  84 module_param(max_num_clients, byte, 0644);
  85 MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
  86
  87 static unsigned int copy_bytes = 1024;
  88 module_param(copy_bytes, uint, 0644);
  89 MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
  90
  91 static bool use_dma;
  92 module_param(use_dma, bool, 0644);
  93 MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
  94
  95 static struct dentry *nt_debugfs_dir;
  96
  97 struct ntb_queue_entry {
  98         /* ntb_queue list reference */
  99         struct list_head entry;
 100         /* pointers to data to be transferred */
 101         void *cb_data;
 102         void *buf;
 103         unsigned int len;
 104         unsigned int flags;
 105
 106         struct ntb_transport_qp *qp;
 107         union {
 108                 struct ntb_payload_header __iomem *tx_hdr;
 109                 struct ntb_payload_header *rx_hdr;
 110         };
 111         unsigned int index;
 112 };
 113
 114 struct ntb_rx_info {
 115         unsigned int entry;
 116 };
 117
 118 struct ntb_transport_qp {
 119         struct ntb_transport_ctx *transport;
 120         struct ntb_dev *ndev;
 121         void *cb_data;
 122         struct dma_chan *tx_dma_chan;
 123         struct dma_chan *rx_dma_chan;
 124
 125         bool client_ready;
 126         bool link_is_up;
 127
 128         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 129         u64 qp_bit;
 130
 131         struct ntb_rx_info __iomem *rx_info;
 132         struct ntb_rx_info *remote_rx_info;
 133
 134         void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 135                            void *data, int len);
 136         struct list_head tx_free_q;
 137         spinlock_t ntb_tx_free_q_lock;
 138         void __iomem *tx_mw;
 139         dma_addr_t tx_mw_phys;
 140         unsigned int tx_index;
 141         unsigned int tx_max_entry;
 142         unsigned int tx_max_frame;
 143
 144         void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 145                            void *data, int len);
 146         struct list_head rx_post_q;
 147         struct list_head rx_pend_q;
 148         struct list_head rx_free_q;
 149         /* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
 150         spinlock_t ntb_rx_q_lock;
 151         void *rx_buff;
 152         unsigned int rx_index;
 153         unsigned int rx_max_entry;
 154         unsigned int rx_max_frame;
 155         dma_cookie_t last_cookie;
 156         struct tasklet_struct rxc_db_work;
 157
 158         void (*event_handler)(void *data, int status);
 159         struct delayed_work link_work;
 160         struct work_struct link_cleanup;
 161
 162         struct dentry *debugfs_dir;
 163         struct dentry *debugfs_stats;
 164
 165         /* Stats */
 166         u64 rx_bytes;
 167         u64 rx_pkts;
 168         u64 rx_ring_empty;
 169         u64 rx_err_no_buf;
 170         u64 rx_err_oflow;
 171         u64 rx_err_ver;
 172         u64 rx_memcpy;
 173         u64 rx_async;
 174         u64 tx_bytes;
 175         u64 tx_pkts;
 176         u64 tx_ring_full;
 177         u64 tx_err_no_buf;
 178         u64 tx_memcpy;
 179         u64 tx_async;
 180 };
 181
 182 struct ntb_transport_mw {
 183         phys_addr_t phys_addr;
 184         resource_size_t phys_size;
 185         resource_size_t xlat_align;
 186         resource_size_t xlat_align_size;
 187         void __iomem *vbase;
 188         size_t xlat_size;
 189         size_t buff_size;
 190         void *virt_addr;
 191         dma_addr_t dma_addr;
 192 };
 193
 194 struct ntb_transport_client_dev {
 195         struct list_head entry;
 196         struct ntb_transport_ctx *nt;
 197         struct device dev;
 198 };
 199
 200 struct ntb_transport_ctx {
 201         struct list_head entry;
 202         struct list_head client_devs;
 203
 204         struct ntb_dev *ndev;
 205
 206         struct ntb_transport_mw *mw_vec;
 207         struct ntb_transport_qp *qp_vec;
 208         unsigned int mw_count;
 209         unsigned int qp_count;
 210         u64 qp_bitmap;
 211         u64 qp_bitmap_free;
 212
 213         bool link_is_up;
 214         struct delayed_work link_work;
 215         struct work_struct link_cleanup;
 216
 217         struct dentry *debugfs_node_dir;
 218 };
 219
 220 enum {
 221         DESC_DONE_FLAG = BIT(0),
 222         LINK_DOWN_FLAG = BIT(1),
 223 };
 224
 225 struct ntb_payload_header {
 226         unsigned int ver;
 227         unsigned int len;
 228         unsigned int flags;
 229 };
 230
 231 enum {
 232         VERSION = 0,
 233         QP_LINKS,
 234         NUM_QPS,
 235         NUM_MWS,
 236         MW0_SZ_HIGH,
 237         MW0_SZ_LOW,
 238         MW1_SZ_HIGH,
 239         MW1_SZ_LOW,
 240         MAX_SPAD,
 241 };
 242
 243 #define dev_client_dev(__dev) \
 244         container_of((__dev), struct ntb_transport_client_dev, dev)
 245
 246 #define drv_client(__drv) \
 247         container_of((__drv), struct ntb_transport_client, driver)
 248
 249 #define QP_TO_MW(nt, qp)        ((qp) % nt->mw_count)
 250 #define NTB_QP_DEF_NUM_ENTRIES  100
 251 #define NTB_LINK_DOWN_TIMEOUT   10
 252
 253 static void ntb_transport_rxc_db(unsigned long data);
 254 static const struct ntb_ctx_ops ntb_transport_ops;
 255 static struct ntb_client ntb_transport_client;
 256
 257 static int ntb_transport_bus_match(struct device *dev,
 258                                    struct device_driver *drv)
 259 {
 260         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 261 }
 262
 263 static int ntb_transport_bus_probe(struct device *dev)
 264 {
 265         const struct ntb_transport_client *client;
 266         int rc = -EINVAL;
 267
 268         get_device(dev);
 269
 270         client = drv_client(dev->driver);
 271         rc = client->probe(dev);
 272         if (rc)
 273                 put_device(dev);
 274
 275         return rc;
 276 }
 277
 278 static int ntb_transport_bus_remove(struct device *dev)
 279 {
 280         const struct ntb_transport_client *client;
 281
 282         client = drv_client(dev->driver);
 283         client->remove(dev);
 284
 285         put_device(dev);
 286
 287         return 0;
 288 }
 289
 290 static struct bus_type ntb_transport_bus = {
 291         .name = "ntb_transport",
 292         .match = ntb_transport_bus_match,
 293         .probe = ntb_transport_bus_probe,
 294         .remove = ntb_transport_bus_remove,
 295 };
 296
 297 static LIST_HEAD(ntb_transport_list);
 298
 299 static int ntb_bus_init(struct ntb_transport_ctx *nt)
 300 {
 301         list_add_tail(&nt->entry, &ntb_transport_list);
 302         return 0;
 303 }
 304
 305 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
 306 {
 307         struct ntb_transport_client_dev *client_dev, *cd;
 308
 309         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 310                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 311                         dev_name(&client_dev->dev));
 312                 list_del(&client_dev->entry);
 313                 device_unregister(&client_dev->dev);
 314         }
 315
 316         list_del(&nt->entry);
 317 }
 318
 319 static void ntb_transport_client_release(struct device *dev)
 320 {
 321         struct ntb_transport_client_dev *client_dev;
 322
 323         client_dev = dev_client_dev(dev);
 324         kfree(client_dev);
 325 }
 326
 327 /**
 328  * ntb_transport_unregister_client_dev - Unregister NTB client device
 329  * @device_name: Name of NTB client device
 330  *
 331  * Unregister an NTB client device with the NTB transport layer
 332  */
 333 void ntb_transport_unregister_client_dev(char *device_name)
 334 {
 335         struct ntb_transport_client_dev *client, *cd;
 336         struct ntb_transport_ctx *nt;
 337
 338         list_for_each_entry(nt, &ntb_transport_list, entry)
 339                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 340                         if (!strncmp(dev_name(&client->dev), device_name,
 341                                      strlen(device_name))) {
 342                                 list_del(&client->entry);
 343                                 device_unregister(&client->dev);
 344                         }
 345 }
 346 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
 347
 348 /**
 349  * ntb_transport_register_client_dev - Register NTB client device
 350  * @device_name: Name of NTB client device
 351  *
 352  * Register an NTB client device with the NTB transport layer
 353  */
 354 int ntb_transport_register_client_dev(char *device_name)
 355 {
 356         struct ntb_transport_client_dev *client_dev;
 357         struct ntb_transport_ctx *nt;
 358         int node;
 359         int rc, i = 0;
 360
 361         if (list_empty(&ntb_transport_list))
 362                 return -ENODEV;
 363
 364         list_for_each_entry(nt, &ntb_transport_list, entry) {
 365                 struct device *dev;
 366
 367                 node = dev_to_node(&nt->ndev->dev);
 368
 369                 client_dev = kzalloc_node(sizeof(*client_dev),
 370                                           GFP_KERNEL, node);
 371                 if (!client_dev) {
 372                         rc = -ENOMEM;
 373                         goto err;
 374                 }
 375
 376                 dev = &client_dev->dev;
 377
 378                 /* setup and register client devices */
 379                 dev_set_name(dev, "%s%d", device_name, i);
 380                 dev->bus = &ntb_transport_bus;
 381                 dev->release = ntb_transport_client_release;
 382                 dev->parent = &nt->ndev->dev;
 383
 384                 rc = device_register(dev);
 385                 if (rc) {
 386                         kfree(client_dev);
 387                         goto err;
 388                 }
 389
 390                 list_add_tail(&client_dev->entry, &nt->client_devs);
 391                 i++;
 392         }
 393
 394         return 0;
 395
 396 err:
 397         ntb_transport_unregister_client_dev(device_name);
 398
 399         return rc;
 400 }
 401 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
 402
 403 /**
 404  * ntb_transport_register_client - Register NTB client driver
 405  * @drv: NTB client driver to be registered
 406  *
 407  * Register an NTB client driver with the NTB transport layer
 408  *
 409  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 410  */
 411 int ntb_transport_register_client(struct ntb_transport_client *drv)
 412 {
 413         drv->driver.bus = &ntb_transport_bus;
 414
 415         if (list_empty(&ntb_transport_list))
 416                 return -ENODEV;
 417
 418         return driver_register(&drv->driver);
 419 }
 420 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
 421
 422 /**
 423  * ntb_transport_unregister_client - Unregister NTB client driver
 424  * @drv: NTB client driver to be unregistered
 425  *
 426  * Unregister an NTB client driver with the NTB transport layer
 427  *
 428  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 429  */
 430 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
 431 {
 432         driver_unregister(&drv->driver);
 433 }
 434 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
 435
 436 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 437                             loff_t *offp)
 438 {
 439         struct ntb_transport_qp *qp;
 440         char *buf;
 441         ssize_t ret, out_offset, out_count;
 442
 443         qp = filp->private_data;
 444
 445         if (!qp || !qp->link_is_up)
 446                 return 0;
 447
 448         out_count = 1000;
 449
 450         buf = kmalloc(out_count, GFP_KERNEL);
 451         if (!buf)
 452                 return -ENOMEM;
 453
 454         out_offset = 0;
 455         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 456                                "\nNTB QP stats:\n\n");
 457         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 458                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 459         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 460                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 461         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 462                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
 463         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 464                                "rx_async - \t%llu\n", qp->rx_async);
 465         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 466                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 467         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 468                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 469         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 470                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 471         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 472                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 473         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 474                                "rx_buff - \t0x%p\n", qp->rx_buff);
 475         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 476                                "rx_index - \t%u\n", qp->rx_index);
 477         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 478                                "rx_max_entry - \t%u\n\n", qp->rx_max_entry);
 479
 480         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 481                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 482         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 483                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 484         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 485                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
 486         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 487                                "tx_async - \t%llu\n", qp->tx_async);
 488         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 489                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 490         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 491                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 492         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 493                                "tx_mw - \t0x%p\n", qp->tx_mw);
 494         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 495                                "tx_index (H) - \t%u\n", qp->tx_index);
 496         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 497                                "RRI (T) - \t%u\n",
 498                                qp->remote_rx_info->entry);
 499         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 500                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
 501         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 502                                "free tx - \t%u\n",
 503                                ntb_transport_tx_free_entry(qp));
 504
 505         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 506                                "\n");
 507         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 508                                "Using TX DMA - \t%s\n",
 509                                qp->tx_dma_chan ? "Yes" : "No");
 510         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 511                                "Using RX DMA - \t%s\n",
 512                                qp->rx_dma_chan ? "Yes" : "No");
 513         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 514                                "QP Link - \t%s\n",
 515                                qp->link_is_up ? "Up" : "Down");
 516         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 517                                "\n");
 518
 519         if (out_offset > out_count)
 520                 out_offset = out_count;
 521
 522         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 523         kfree(buf);
 524         return ret;
 525 }
 526
 527 static const struct file_operations ntb_qp_debugfs_stats = {
 528         .owner = THIS_MODULE,
 529         .open = simple_open,
 530         .read = debugfs_read,
 531 };
 532
 533 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 534                          struct list_head *list)
 535 {
 536         unsigned long flags;
 537
 538         spin_lock_irqsave(lock, flags);
 539         list_add_tail(entry, list);
 540         spin_unlock_irqrestore(lock, flags);
 541 }
 542
 543 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 544                                            struct list_head *list)
 545 {
 546         struct ntb_queue_entry *entry;
 547         unsigned long flags;
 548
 549         spin_lock_irqsave(lock, flags);
 550         if (list_empty(list)) {
 551                 entry = NULL;
 552                 goto out;
 553         }
 554         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 555         list_del(&entry->entry);
 556
 557 out:
 558         spin_unlock_irqrestore(lock, flags);
 559
 560         return entry;
 561 }
 562
 563 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
 564                                            struct list_head *list,
 565                                            struct list_head *to_list)
 566 {
 567         struct ntb_queue_entry *entry;
 568         unsigned long flags;
 569
 570         spin_lock_irqsave(lock, flags);
 571
 572         if (list_empty(list)) {
 573                 entry = NULL;
 574         } else {
 575                 entry = list_first_entry(list, struct ntb_queue_entry, entry);
 576                 list_move_tail(&entry->entry, to_list);
 577         }
 578
 579         spin_unlock_irqrestore(lock, flags);
 580
 581         return entry;
 582 }
 583
 584 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 585                                      unsigned int qp_num)
 586 {
 587         struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
 588         struct ntb_transport_mw *mw;
 589         unsigned int rx_size, num_qps_mw;
 590         unsigned int mw_num, mw_count, qp_count;
 591         unsigned int i;
 592
 593         mw_count = nt->mw_count;
 594         qp_count = nt->qp_count;
 595
 596         mw_num = QP_TO_MW(nt, qp_num);
 597         mw = &nt->mw_vec[mw_num];
 598
 599         if (!mw->virt_addr)
 600                 return -ENOMEM;
 601
 602         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 603                 num_qps_mw = qp_count / mw_count + 1;
 604         else
 605                 num_qps_mw = qp_count / mw_count;
 606
 607         rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
 608         qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
 609         rx_size -= sizeof(struct ntb_rx_info);
 610
 611         qp->remote_rx_info = qp->rx_buff + rx_size;
 612
 613         /* Due to housekeeping, there must be atleast 2 buffs */
 614         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
 615         qp->rx_max_entry = rx_size / qp->rx_max_frame;
 616         qp->rx_index = 0;
 617
 618         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
 619
 620         /* setup the hdr offsets with 0's */
 621         for (i = 0; i < qp->rx_max_entry; i++) {
 622                 void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
 623                                 sizeof(struct ntb_payload_header));
 624                 memset(offset, 0, sizeof(struct ntb_payload_header));
 625         }
 626
 627         qp->rx_pkts = 0;
 628         qp->tx_pkts = 0;
 629         qp->tx_index = 0;
 630
 631         return 0;
 632 }
 633
 634 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 635 {
 636         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 637         struct pci_dev *pdev = nt->ndev->pdev;
 638
 639         if (!mw->virt_addr)
 640                 return;
 641
 642         ntb_mw_clear_trans(nt->ndev, num_mw);
 643         dma_free_coherent(&pdev->dev, mw->buff_size,
 644                           mw->virt_addr, mw->dma_addr);
 645         mw->xlat_size = 0;
 646         mw->buff_size = 0;
 647         mw->virt_addr = NULL;
 648 }
 649
 650 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 651                       resource_size_t size)
 652 {
 653         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 654         struct pci_dev *pdev = nt->ndev->pdev;
 655         size_t xlat_size, buff_size;
 656         int rc;
 657
 658         if (!size)
 659                 return -EINVAL;
 660
 661         xlat_size = round_up(size, mw->xlat_align_size);
 662         buff_size = round_up(size, mw->xlat_align);
 663
 664         /* No need to re-setup */
 665         if (mw->xlat_size == xlat_size)
 666                 return 0;
 667
 668         if (mw->buff_size)
 669                 ntb_free_mw(nt, num_mw);
 670
 671         /* Alloc memory for receiving data.  Must be aligned */
 672         mw->xlat_size = xlat_size;
 673         mw->buff_size = buff_size;
 674
 675         mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
 676                                            &mw->dma_addr, GFP_KERNEL);
 677         if (!mw->virt_addr) {
 678                 mw->xlat_size = 0;
 679                 mw->buff_size = 0;
 680                 dev_err(&pdev->dev, "Unable to alloc MW buff of size %zu\n",
 681                         buff_size);
 682                 return -ENOMEM;
 683         }
 684
 685         /*
 686          * we must ensure that the memory address allocated is BAR size
 687          * aligned in order for the XLAT register to take the value. This
 688          * is a requirement of the hardware. It is recommended to setup CMA
 689          * for BAR sizes equal or greater than 4MB.
 690          */
 691         if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
 692                 dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
 693                         &mw->dma_addr);
 694                 ntb_free_mw(nt, num_mw);
 695                 return -ENOMEM;
 696         }
 697
 698         /* Notify HW the memory location of the receive buffer */
 699         rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
 700         if (rc) {
 701                 dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
 702                 ntb_free_mw(nt, num_mw);
 703                 return -EIO;
 704         }
 705
 706         return 0;
 707 }
 708
 709 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 710 {
 711         qp->link_is_up = false;
 712
 713         qp->tx_index = 0;
 714         qp->rx_index = 0;
 715         qp->rx_bytes = 0;
 716         qp->rx_pkts = 0;
 717         qp->rx_ring_empty = 0;
 718         qp->rx_err_no_buf = 0;
 719         qp->rx_err_oflow = 0;
 720         qp->rx_err_ver = 0;
 721         qp->rx_memcpy = 0;
 722         qp->rx_async = 0;
 723         qp->tx_bytes = 0;
 724         qp->tx_pkts = 0;
 725         qp->tx_ring_full = 0;
 726         qp->tx_err_no_buf = 0;
 727         qp->tx_memcpy = 0;
 728         qp->tx_async = 0;
 729 }
 730
 731 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
 732 {
 733         struct ntb_transport_ctx *nt = qp->transport;
 734         struct pci_dev *pdev = nt->ndev->pdev;
 735
 736         dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
 737
 738         cancel_delayed_work_sync(&qp->link_work);
 739         ntb_qp_link_down_reset(qp);
 740
 741         if (qp->event_handler)
 742                 qp->event_handler(qp->cb_data, qp->link_is_up);
 743 }
 744
 745 static void ntb_qp_link_cleanup_work(struct work_struct *work)
 746 {
 747         struct ntb_transport_qp *qp = container_of(work,
 748                                                    struct ntb_transport_qp,
 749                                                    link_cleanup);
 750         struct ntb_transport_ctx *nt = qp->transport;
 751
 752         ntb_qp_link_cleanup(qp);
 753
 754         if (nt->link_is_up)
 755                 schedule_delayed_work(&qp->link_work,
 756                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 757 }
 758
 759 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 760 {
 761         schedule_work(&qp->link_cleanup);
 762 }
 763
 764 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 765 {
 766         struct ntb_transport_qp *qp;
 767         u64 qp_bitmap_alloc;
 768         int i;
 769
 770         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
 771
 772         /* Pass along the info to any clients */
 773         for (i = 0; i < nt->qp_count; i++)
 774                 if (qp_bitmap_alloc & BIT_ULL(i)) {
 775                         qp = &nt->qp_vec[i];
 776                         ntb_qp_link_cleanup(qp);
 777                         cancel_work_sync(&qp->link_cleanup);
 778                         cancel_delayed_work_sync(&qp->link_work);
 779                 }
 780
 781         if (!nt->link_is_up)
 782                 cancel_delayed_work_sync(&nt->link_work);
 783
 784         /* The scratchpad registers keep the values if the remote side
 785          * goes down, blast them now to give them a sane value the next
 786          * time they are accessed
 787          */
 788         for (i = 0; i < MAX_SPAD; i++)
 789                 ntb_spad_write(nt->ndev, i, 0);
 790 }
 791
 792 static void ntb_transport_link_cleanup_work(struct work_struct *work)
 793 {
 794         struct ntb_transport_ctx *nt =
 795                 container_of(work, struct ntb_transport_ctx, link_cleanup);
 796
 797         ntb_transport_link_cleanup(nt);
 798 }
 799
 800 static void ntb_transport_event_callback(void *data)
 801 {
 802         struct ntb_transport_ctx *nt = data;
 803
 804         if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
 805                 schedule_delayed_work(&nt->link_work, 0);
 806         else
 807                 schedule_work(&nt->link_cleanup);
 808 }
 809
 810 static void ntb_transport_link_work(struct work_struct *work)
 811 {
 812         struct ntb_transport_ctx *nt =
 813                 container_of(work, struct ntb_transport_ctx, link_work.work);
 814         struct ntb_dev *ndev = nt->ndev;
 815         struct pci_dev *pdev = ndev->pdev;
 816         resource_size_t size;
 817         u32 val;
 818         int rc, i, spad;
 819
 820         /* send the local info, in the opposite order of the way we read it */
 821         for (i = 0; i < nt->mw_count; i++) {
 822                 size = nt->mw_vec[i].phys_size;
 823
 824                 if (max_mw_size && size > max_mw_size)
 825                         size = max_mw_size;
 826
 827                 spad = MW0_SZ_HIGH + (i * 2);
 828                 ntb_peer_spad_write(ndev, spad, upper_32_bits(size));
 829
 830                 spad = MW0_SZ_LOW + (i * 2);
 831                 ntb_peer_spad_write(ndev, spad, lower_32_bits(size));
 832         }
 833
 834         ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
 835
 836         ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
 837
 838         ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
 839
 840         /* Query the remote side for its info */
 841         val = ntb_spad_read(ndev, VERSION);
 842         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 843         if (val != NTB_TRANSPORT_VERSION)
 844                 goto out;
 845
 846         val = ntb_spad_read(ndev, NUM_QPS);
 847         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 848         if (val != nt->qp_count)
 849                 goto out;
 850
 851         val = ntb_spad_read(ndev, NUM_MWS);
 852         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
 853         if (val != nt->mw_count)
 854                 goto out;
 855
 856         for (i = 0; i < nt->mw_count; i++) {
 857                 u64 val64;
 858
 859                 val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
 860                 val64 = (u64)val << 32;
 861
 862                 val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
 863                 val64 |= val;
 864
 865                 dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
 866
 867                 rc = ntb_set_mw(nt, i, val64);
 868                 if (rc)
 869                         goto out1;
 870         }
 871
 872         nt->link_is_up = true;
 873
 874         for (i = 0; i < nt->qp_count; i++) {
 875                 struct ntb_transport_qp *qp = &nt->qp_vec[i];
 876
 877                 ntb_transport_setup_qp_mw(nt, i);
 878
 879                 if (qp->client_ready)
 880                         schedule_delayed_work(&qp->link_work, 0);
 881         }
 882
 883         return;
 884
 885 out1:
 886         for (i = 0; i < nt->mw_count; i++)
 887                 ntb_free_mw(nt, i);
 888 out:
 889         if (ntb_link_is_up(ndev, NULL, NULL) == 1)
 890                 schedule_delayed_work(&nt->link_work,
 891                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 892 }
 893
 894 static void ntb_qp_link_work(struct work_struct *work)
 895 {
 896         struct ntb_transport_qp *qp = container_of(work,
 897                                                    struct ntb_transport_qp,
 898                                                    link_work.work);
 899         struct pci_dev *pdev = qp->ndev->pdev;
 900         struct ntb_transport_ctx *nt = qp->transport;
 901         int val;
 902
 903         WARN_ON(!nt->link_is_up);
 904
 905         val = ntb_spad_read(nt->ndev, QP_LINKS);
 906
 907         ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
 908
 909         /* query remote spad for qp ready bits */
 910         ntb_peer_spad_read(nt->ndev, QP_LINKS);
 911         dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
 912
 913         /* See if the remote side is up */
 914         if (val & BIT(qp->qp_num)) {
 915                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 916                 qp->link_is_up = true;
 917
 918                 if (qp->event_handler)
 919                         qp->event_handler(qp->cb_data, qp->link_is_up);
 920
 921                 tasklet_schedule(&qp->rxc_db_work);
 922         } else if (nt->link_is_up)
 923                 schedule_delayed_work(&qp->link_work,
 924                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 925 }
 926
 927 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 928                                     unsigned int qp_num)
 929 {
 930         struct ntb_transport_qp *qp;
 931         phys_addr_t mw_base;
 932         resource_size_t mw_size;
 933         unsigned int num_qps_mw, tx_size;
 934         unsigned int mw_num, mw_count, qp_count;
 935         u64 qp_offset;
 936
 937         mw_count = nt->mw_count;
 938         qp_count = nt->qp_count;
 939
 940         mw_num = QP_TO_MW(nt, qp_num);
 941
 942         qp = &nt->qp_vec[qp_num];
 943         qp->qp_num = qp_num;
 944         qp->transport = nt;
 945         qp->ndev = nt->ndev;
 946         qp->client_ready = false;
 947         qp->event_handler = NULL;
 948         ntb_qp_link_down_reset(qp);
 949
 950         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 951                 num_qps_mw = qp_count / mw_count + 1;
 952         else
 953                 num_qps_mw = qp_count / mw_count;
 954
 955         mw_base = nt->mw_vec[mw_num].phys_addr;
 956         mw_size = nt->mw_vec[mw_num].phys_size;
 957
 958         tx_size = (unsigned int)mw_size / num_qps_mw;
 959         qp_offset = tx_size * (qp_num / mw_count);
 960
 961         qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
 962         if (!qp->tx_mw)
 963                 return -EINVAL;
 964
 965         qp->tx_mw_phys = mw_base + qp_offset;
 966         if (!qp->tx_mw_phys)
 967                 return -EINVAL;
 968
 969         tx_size -= sizeof(struct ntb_rx_info);
 970         qp->rx_info = qp->tx_mw + tx_size;
 971
 972         /* Due to housekeeping, there must be atleast 2 buffs */
 973         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 974         qp->tx_max_entry = tx_size / qp->tx_max_frame;
 975
 976         if (nt->debugfs_node_dir) {
 977                 char debugfs_name[4];
 978
 979                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 980                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 981                                                      nt->debugfs_node_dir);
 982
 983                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 984                                                         qp->debugfs_dir, qp,
 985                                                         &ntb_qp_debugfs_stats);
 986         } else {
 987                 qp->debugfs_dir = NULL;
 988                 qp->debugfs_stats = NULL;
 989         }
 990
 991         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 992         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
 993
 994         spin_lock_init(&qp->ntb_rx_q_lock);
 995         spin_lock_init(&qp->ntb_tx_free_q_lock);
 996
 997         INIT_LIST_HEAD(&qp->rx_post_q);
 998         INIT_LIST_HEAD(&qp->rx_pend_q);
 999         INIT_LIST_HEAD(&qp->rx_free_q);
1000         INIT_LIST_HEAD(&qp->tx_free_q);
1001
1002         tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
1003                      (unsigned long)qp);
1004
1005         return 0;
1006 }
1007
1008 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
1009 {
1010         struct ntb_transport_ctx *nt;
1011         struct ntb_transport_mw *mw;
1012         unsigned int mw_count, qp_count;
1013         u64 qp_bitmap;
1014         int node;
1015         int rc, i;
1016
1017         if (ntb_db_is_unsafe(ndev))
1018                 dev_dbg(&ndev->dev,
1019                         "doorbell is unsafe, proceed anyway...\n");
1020         if (ntb_spad_is_unsafe(ndev))
1021                 dev_dbg(&ndev->dev,
1022                         "scratchpad is unsafe, proceed anyway...\n");
1023
1024         node = dev_to_node(&ndev->dev);
1025
1026         nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1027         if (!nt)
1028                 return -ENOMEM;
1029
1030         nt->ndev = ndev;
1031
1032         mw_count = ntb_mw_count(ndev);
1033
1034         nt->mw_count = mw_count;
1035
1036         nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
1037                                   GFP_KERNEL, node);
1038         if (!nt->mw_vec) {
1039                 rc = -ENOMEM;
1040                 goto err;
1041         }
1042
1043         for (i = 0; i < mw_count; i++) {
1044                 mw = &nt->mw_vec[i];
1045
1046                 rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
1047                                       &mw->xlat_align, &mw->xlat_align_size);
1048                 if (rc)
1049                         goto err1;
1050
1051                 mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1052                 if (!mw->vbase) {
1053                         rc = -ENOMEM;
1054                         goto err1;
1055                 }
1056
1057                 mw->buff_size = 0;
1058                 mw->xlat_size = 0;
1059                 mw->virt_addr = NULL;
1060                 mw->dma_addr = 0;
1061         }
1062
1063         qp_bitmap = ntb_db_valid_mask(ndev);
1064
1065         qp_count = ilog2(qp_bitmap);
1066         if (max_num_clients && max_num_clients < qp_count)
1067                 qp_count = max_num_clients;
1068         else if (mw_count < qp_count)
1069                 qp_count = mw_count;
1070
1071         qp_bitmap &= BIT_ULL(qp_count) - 1;
1072
1073         nt->qp_count = qp_count;
1074         nt->qp_bitmap = qp_bitmap;
1075         nt->qp_bitmap_free = qp_bitmap;
1076
1077         nt->qp_vec = kzalloc_node(qp_count * sizeof(*nt->qp_vec),
1078                                   GFP_KERNEL, node);
1079         if (!nt->qp_vec) {
1080                 rc = -ENOMEM;
1081                 goto err1;
1082         }
1083
1084         if (nt_debugfs_dir) {
1085                 nt->debugfs_node_dir =
1086                         debugfs_create_dir(pci_name(ndev->pdev),
1087                                            nt_debugfs_dir);
1088         }
1089
1090         for (i = 0; i < qp_count; i++) {
1091                 rc = ntb_transport_init_queue(nt, i);
1092                 if (rc)
1093                         goto err2;
1094         }
1095
1096         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1097         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1098
1099         rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1100         if (rc)
1101                 goto err2;
1102
1103         INIT_LIST_HEAD(&nt->client_devs);
1104         rc = ntb_bus_init(nt);
1105         if (rc)
1106                 goto err3;
1107
1108         nt->link_is_up = false;
1109         ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1110         ntb_link_event(ndev);
1111
1112         return 0;
1113
1114 err3:
1115         ntb_clear_ctx(ndev);
1116 err2:
1117         kfree(nt->qp_vec);
1118 err1:
1119         while (i--) {
1120                 mw = &nt->mw_vec[i];
1121                 iounmap(mw->vbase);
1122         }
1123         kfree(nt->mw_vec);
1124 err:
1125         kfree(nt);
1126         return rc;
1127 }
1128
1129 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1130 {
1131         struct ntb_transport_ctx *nt = ndev->ctx;
1132         struct ntb_transport_qp *qp;
1133         u64 qp_bitmap_alloc;
1134         int i;
1135
1136         ntb_transport_link_cleanup(nt);
1137         cancel_work_sync(&nt->link_cleanup);
1138         cancel_delayed_work_sync(&nt->link_work);
1139
1140         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1141
1142         /* verify that all the qp's are freed */
1143         for (i = 0; i < nt->qp_count; i++) {
1144                 qp = &nt->qp_vec[i];
1145                 if (qp_bitmap_alloc & BIT_ULL(i))
1146                         ntb_transport_free_queue(qp);
1147                 debugfs_remove_recursive(qp->debugfs_dir);
1148         }
1149
1150         ntb_link_disable(ndev);
1151         ntb_clear_ctx(ndev);
1152
1153         ntb_bus_remove(nt);
1154
1155         for (i = nt->mw_count; i--; ) {
1156                 ntb_free_mw(nt, i);
1157                 iounmap(nt->mw_vec[i].vbase);
1158         }
1159
1160         kfree(nt->qp_vec);
1161         kfree(nt->mw_vec);
1162         kfree(nt);
1163 }
1164
1165 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1166 {
1167         struct ntb_queue_entry *entry;
1168         void *cb_data;
1169         unsigned int len;
1170         unsigned long irqflags;
1171
1172         spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1173
1174         while (!list_empty(&qp->rx_post_q)) {
1175                 entry = list_first_entry(&qp->rx_post_q,
1176                                          struct ntb_queue_entry, entry);
1177                 if (!(entry->flags & DESC_DONE_FLAG))
1178                         break;
1179
1180                 entry->rx_hdr->flags = 0;
1181                 iowrite32(entry->index, &qp->rx_info->entry);
1182
1183                 cb_data = entry->cb_data;
1184                 len = entry->len;
1185
1186                 list_move_tail(&entry->entry, &qp->rx_free_q);
1187
1188                 spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1189
1190                 if (qp->rx_handler && qp->client_ready)
1191                         qp->rx_handler(qp, qp->cb_data, cb_data, len);
1192
1193                 spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1194         }
1195
1196         spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1197 }
1198
1199 static void ntb_rx_copy_callback(void *data)
1200 {
1201         struct ntb_queue_entry *entry = data;
1202
1203         entry->flags |= DESC_DONE_FLAG;
1204
1205         ntb_complete_rxc(entry->qp);
1206 }
1207
1208 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1209 {
1210         void *buf = entry->buf;
1211         size_t len = entry->len;
1212
1213         memcpy(buf, offset, len);
1214
1215         /* Ensure that the data is fully copied out before clearing the flag */
1216         wmb();
1217
1218         ntb_rx_copy_callback(entry);
1219 }
1220
1221 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1222 {
1223         struct dma_async_tx_descriptor *txd;
1224         struct ntb_transport_qp *qp = entry->qp;
1225         struct dma_chan *chan = qp->rx_dma_chan;
1226         struct dma_device *device;
1227         size_t pay_off, buff_off, len;
1228         struct dmaengine_unmap_data *unmap;
1229         dma_cookie_t cookie;
1230         void *buf = entry->buf;
1231
1232         len = entry->len;
1233
1234         if (!chan)
1235                 goto err;
1236
1237         if (len < copy_bytes)
1238                 goto err;
1239
1240         device = chan->device;
1241         pay_off = (size_t)offset & ~PAGE_MASK;
1242         buff_off = (size_t)buf & ~PAGE_MASK;
1243
1244         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1245                 goto err;
1246
1247         unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1248         if (!unmap)
1249                 goto err;
1250
1251         unmap->len = len;
1252         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1253                                       pay_off, len, DMA_TO_DEVICE);
1254         if (dma_mapping_error(device->dev, unmap->addr[0]))
1255                 goto err_get_unmap;
1256
1257         unmap->to_cnt = 1;
1258
1259         unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1260                                       buff_off, len, DMA_FROM_DEVICE);
1261         if (dma_mapping_error(device->dev, unmap->addr[1]))
1262                 goto err_get_unmap;
1263
1264         unmap->from_cnt = 1;
1265
1266         txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1267                                              unmap->addr[0], len,
1268                                              DMA_PREP_INTERRUPT);
1269         if (!txd)
1270                 goto err_get_unmap;
1271
1272         txd->callback = ntb_rx_copy_callback;
1273         txd->callback_param = entry;
1274         dma_set_unmap(txd, unmap);
1275
1276         cookie = dmaengine_submit(txd);
1277         if (dma_submit_error(cookie))
1278                 goto err_set_unmap;
1279
1280         dmaengine_unmap_put(unmap);
1281
1282         qp->last_cookie = cookie;
1283
1284         qp->rx_async++;
1285
1286         return;
1287
1288 err_set_unmap:
1289         dmaengine_unmap_put(unmap);
1290 err_get_unmap:
1291         dmaengine_unmap_put(unmap);
1292 err:
1293         ntb_memcpy_rx(entry, offset);
1294         qp->rx_memcpy++;
1295 }
1296
1297 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1298 {
1299         struct ntb_payload_header *hdr;
1300         struct ntb_queue_entry *entry;
1301         void *offset;
1302
1303         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1304         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1305
1306         dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1307                 qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1308
1309         if (!(hdr->flags & DESC_DONE_FLAG)) {
1310                 dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1311                 qp->rx_ring_empty++;
1312                 return -EAGAIN;
1313         }
1314
1315         if (hdr->flags & LINK_DOWN_FLAG) {
1316                 dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1317                 ntb_qp_link_down(qp);
1318                 hdr->flags = 0;
1319                 return -EAGAIN;
1320         }
1321
1322         if (hdr->ver != (u32)qp->rx_pkts) {
1323                 dev_dbg(&qp->ndev->pdev->dev,
1324                         "version mismatch, expected %llu - got %u\n",
1325                         qp->rx_pkts, hdr->ver);
1326                 qp->rx_err_ver++;
1327                 return -EIO;
1328         }
1329
1330         entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1331         if (!entry) {
1332                 dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1333                 qp->rx_err_no_buf++;
1334                 return -EAGAIN;
1335         }
1336
1337         entry->rx_hdr = hdr;
1338         entry->index = qp->rx_index;
1339
1340         if (hdr->len > entry->len) {
1341                 dev_dbg(&qp->ndev->pdev->dev,
1342                         "receive buffer overflow! Wanted %d got %d\n",
1343                         hdr->len, entry->len);
1344                 qp->rx_err_oflow++;
1345
1346                 entry->len = -EIO;
1347                 entry->flags |= DESC_DONE_FLAG;
1348
1349                 ntb_complete_rxc(qp);
1350         } else {
1351                 dev_dbg(&qp->ndev->pdev->dev,
1352                         "RX OK index %u ver %u size %d into buf size %d\n",
1353                         qp->rx_index, hdr->ver, hdr->len, entry->len);
1354
1355                 qp->rx_bytes += hdr->len;
1356                 qp->rx_pkts++;
1357
1358                 entry->len = hdr->len;
1359
1360                 ntb_async_rx(entry, offset);
1361         }
1362
1363         qp->rx_index++;
1364         qp->rx_index %= qp->rx_max_entry;
1365
1366         return 0;
1367 }
1368
1369 static void ntb_transport_rxc_db(unsigned long data)
1370 {
1371         struct ntb_transport_qp *qp = (void *)data;
1372         int rc, i;
1373
1374         dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1375                 __func__, qp->qp_num);
1376
1377         /* Limit the number of packets processed in a single interrupt to
1378          * provide fairness to others
1379          */
1380         for (i = 0; i < qp->rx_max_entry; i++) {
1381                 rc = ntb_process_rxc(qp);
1382                 if (rc)
1383                         break;
1384         }
1385
1386         if (i && qp->rx_dma_chan)
1387                 dma_async_issue_pending(qp->rx_dma_chan);
1388
1389         if (i == qp->rx_max_entry) {
1390                 /* there is more work to do */
1391                 tasklet_schedule(&qp->rxc_db_work);
1392         } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1393                 /* the doorbell bit is set: clear it */
1394                 ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1395                 /* ntb_db_read ensures ntb_db_clear write is committed */
1396                 ntb_db_read(qp->ndev);
1397
1398                 /* an interrupt may have arrived between finishing
1399                  * ntb_process_rxc and clearing the doorbell bit:
1400                  * there might be some more work to do.
1401                  */
1402                 tasklet_schedule(&qp->rxc_db_work);
1403         }
1404 }
1405
1406 static void ntb_tx_copy_callback(void *data)
1407 {
1408         struct ntb_queue_entry *entry = data;
1409         struct ntb_transport_qp *qp = entry->qp;
1410         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1411
1412         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1413
1414         ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1415
1416         /* The entry length can only be zero if the packet is intended to be a
1417          * "link down" or similar.  Since no payload is being sent in these
1418          * cases, there is nothing to add to the completion queue.
1419          */
1420         if (entry->len > 0) {
1421                 qp->tx_bytes += entry->len;
1422
1423                 if (qp->tx_handler)
1424                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1425                                        entry->len);
1426         }
1427
1428         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1429 }
1430
1431 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1432 {
1433 #ifdef ARCH_HAS_NOCACHE_UACCESS
1434         /*
1435          * Using non-temporal mov to improve performance on non-cached
1436          * writes, even though we aren't actually copying from user space.
1437          */
1438         __copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1439 #else
1440         memcpy_toio(offset, entry->buf, entry->len);
1441 #endif
1442
1443         /* Ensure that the data is fully copied out before setting the flags */
1444         wmb();
1445
1446         ntb_tx_copy_callback(entry);
1447 }
1448
1449 static void ntb_async_tx(struct ntb_transport_qp *qp,
1450                          struct ntb_queue_entry *entry)
1451 {
1452         struct ntb_payload_header __iomem *hdr;
1453         struct dma_async_tx_descriptor *txd;
1454         struct dma_chan *chan = qp->tx_dma_chan;
1455         struct dma_device *device;
1456         size_t dest_off, buff_off;
1457         struct dmaengine_unmap_data *unmap;
1458         dma_addr_t dest;
1459         dma_cookie_t cookie;
1460         void __iomem *offset;
1461         size_t len = entry->len;
1462         void *buf = entry->buf;
1463
1464         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1465         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1466         entry->tx_hdr = hdr;
1467
1468         iowrite32(entry->len, &hdr->len);
1469         iowrite32((u32)qp->tx_pkts, &hdr->ver);
1470
1471         if (!chan)
1472                 goto err;
1473
1474         if (len < copy_bytes)
1475                 goto err;
1476
1477         device = chan->device;
1478         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1479         buff_off = (size_t)buf & ~PAGE_MASK;
1480         dest_off = (size_t)dest & ~PAGE_MASK;
1481
1482         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1483                 goto err;
1484
1485         unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1486         if (!unmap)
1487                 goto err;
1488
1489         unmap->len = len;
1490         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1491                                       buff_off, len, DMA_TO_DEVICE);
1492         if (dma_mapping_error(device->dev, unmap->addr[0]))
1493                 goto err_get_unmap;
1494
1495         unmap->to_cnt = 1;
1496
1497         txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1498                                              DMA_PREP_INTERRUPT);
1499         if (!txd)
1500                 goto err_get_unmap;
1501
1502         txd->callback = ntb_tx_copy_callback;
1503         txd->callback_param = entry;
1504         dma_set_unmap(txd, unmap);
1505
1506         cookie = dmaengine_submit(txd);
1507         if (dma_submit_error(cookie))
1508                 goto err_set_unmap;
1509
1510         dmaengine_unmap_put(unmap);
1511
1512         dma_async_issue_pending(chan);
1513         qp->tx_async++;
1514
1515         return;
1516 err_set_unmap:
1517         dmaengine_unmap_put(unmap);
1518 err_get_unmap:
1519         dmaengine_unmap_put(unmap);
1520 err:
1521         ntb_memcpy_tx(entry, offset);
1522         qp->tx_memcpy++;
1523 }
1524
1525 static int ntb_process_tx(struct ntb_transport_qp *qp,
1526                           struct ntb_queue_entry *entry)
1527 {
1528         if (qp->tx_index == qp->remote_rx_info->entry) {
1529                 qp->tx_ring_full++;
1530                 return -EAGAIN;
1531         }
1532
1533         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1534                 if (qp->tx_handler)
1535                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1536
1537                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1538                              &qp->tx_free_q);
1539                 return 0;
1540         }
1541
1542         ntb_async_tx(qp, entry);
1543
1544         qp->tx_index++;
1545         qp->tx_index %= qp->tx_max_entry;
1546
1547         qp->tx_pkts++;
1548
1549         return 0;
1550 }
1551
1552 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1553 {
1554         struct pci_dev *pdev = qp->ndev->pdev;
1555         struct ntb_queue_entry *entry;
1556         int i, rc;
1557
1558         if (!qp->link_is_up)
1559                 return;
1560
1561         dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1562
1563         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1564                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1565                 if (entry)
1566                         break;
1567                 msleep(100);
1568         }
1569
1570         if (!entry)
1571                 return;
1572
1573         entry->cb_data = NULL;
1574         entry->buf = NULL;
1575         entry->len = 0;
1576         entry->flags = LINK_DOWN_FLAG;
1577
1578         rc = ntb_process_tx(qp, entry);
1579         if (rc)
1580                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1581                         qp->qp_num);
1582
1583         ntb_qp_link_down_reset(qp);
1584 }
1585
1586 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1587 {
1588         return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1589 }
1590
1591 /**
1592  * ntb_transport_create_queue - Create a new NTB transport layer queue
1593  * @rx_handler: receive callback function
1594  * @tx_handler: transmit callback function
1595  * @event_handler: event callback function
1596  *
1597  * Create a new NTB transport layer queue and provide the queue with a callback
1598  * routine for both transmit and receive.  The receive callback routine will be
1599  * used to pass up data when the transport has received it on the queue.   The
1600  * transmit callback routine will be called when the transport has completed the
1601  * transmission of the data on the queue and the data is ready to be freed.
1602  *
1603  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1604  */
1605 struct ntb_transport_qp *
1606 ntb_transport_create_queue(void *data, struct device *client_dev,
1607                            const struct ntb_queue_handlers *handlers)
1608 {
1609         struct ntb_dev *ndev;
1610         struct pci_dev *pdev;
1611         struct ntb_transport_ctx *nt;
1612         struct ntb_queue_entry *entry;
1613         struct ntb_transport_qp *qp;
1614         u64 qp_bit;
1615         unsigned int free_queue;
1616         dma_cap_mask_t dma_mask;
1617         int node;
1618         int i;
1619
1620         ndev = dev_ntb(client_dev->parent);
1621         pdev = ndev->pdev;
1622         nt = ndev->ctx;
1623
1624         node = dev_to_node(&ndev->dev);
1625
1626         free_queue = ffs(nt->qp_bitmap);
1627         if (!free_queue)
1628                 goto err;
1629
1630         /* decrement free_queue to make it zero based */
1631         free_queue--;
1632
1633         qp = &nt->qp_vec[free_queue];
1634         qp_bit = BIT_ULL(qp->qp_num);
1635
1636         nt->qp_bitmap_free &= ~qp_bit;
1637
1638         qp->cb_data = data;
1639         qp->rx_handler = handlers->rx_handler;
1640         qp->tx_handler = handlers->tx_handler;
1641         qp->event_handler = handlers->event_handler;
1642
1643         dma_cap_zero(dma_mask);
1644         dma_cap_set(DMA_MEMCPY, dma_mask);
1645
1646         if (use_dma) {
1647                 qp->tx_dma_chan =
1648                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1649                                             (void *)(unsigned long)node);
1650                 if (!qp->tx_dma_chan)
1651                         dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
1652
1653                 qp->rx_dma_chan =
1654                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1655                                             (void *)(unsigned long)node);
1656                 if (!qp->rx_dma_chan)
1657                         dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
1658         } else {
1659                 qp->tx_dma_chan = NULL;
1660                 qp->rx_dma_chan = NULL;
1661         }
1662
1663         dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
1664                 qp->tx_dma_chan ? "DMA" : "CPU");
1665
1666         dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
1667                 qp->rx_dma_chan ? "DMA" : "CPU");
1668
1669         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1670                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1671                 if (!entry)
1672                         goto err1;
1673
1674                 entry->qp = qp;
1675                 ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
1676                              &qp->rx_free_q);
1677         }
1678
1679         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1680                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1681                 if (!entry)
1682                         goto err2;
1683
1684                 entry->qp = qp;
1685                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1686                              &qp->tx_free_q);
1687         }
1688
1689         ntb_db_clear(qp->ndev, qp_bit);
1690         ntb_db_clear_mask(qp->ndev, qp_bit);
1691
1692         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1693
1694         return qp;
1695
1696 err2:
1697         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1698                 kfree(entry);
1699 err1:
1700         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1701                 kfree(entry);
1702         if (qp->tx_dma_chan)
1703                 dma_release_channel(qp->tx_dma_chan);
1704         if (qp->rx_dma_chan)
1705                 dma_release_channel(qp->rx_dma_chan);
1706         nt->qp_bitmap_free |= qp_bit;
1707 err:
1708         return NULL;
1709 }
1710 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1711
1712 /**
1713  * ntb_transport_free_queue - Frees NTB transport queue
1714  * @qp: NTB queue to be freed
1715  *
1716  * Frees NTB transport queue
1717  */
1718 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1719 {
1720         struct pci_dev *pdev;
1721         struct ntb_queue_entry *entry;
1722         u64 qp_bit;
1723
1724         if (!qp)
1725                 return;
1726
1727         pdev = qp->ndev->pdev;
1728
1729         if (qp->tx_dma_chan) {
1730                 struct dma_chan *chan = qp->tx_dma_chan;
1731                 /* Putting the dma_chan to NULL will force any new traffic to be
1732                  * processed by the CPU instead of the DAM engine
1733                  */
1734                 qp->tx_dma_chan = NULL;
1735
1736                 /* Try to be nice and wait for any queued DMA engine
1737                  * transactions to process before smashing it with a rock
1738                  */
1739                 dma_sync_wait(chan, qp->last_cookie);
1740                 dmaengine_terminate_all(chan);
1741                 dma_release_channel(chan);
1742         }
1743
1744         if (qp->rx_dma_chan) {
1745                 struct dma_chan *chan = qp->rx_dma_chan;
1746                 /* Putting the dma_chan to NULL will force any new traffic to be
1747                  * processed by the CPU instead of the DAM engine
1748                  */
1749                 qp->rx_dma_chan = NULL;
1750
1751                 /* Try to be nice and wait for any queued DMA engine
1752                  * transactions to process before smashing it with a rock
1753                  */
1754                 dma_sync_wait(chan, qp->last_cookie);
1755                 dmaengine_terminate_all(chan);
1756                 dma_release_channel(chan);
1757         }
1758
1759         qp_bit = BIT_ULL(qp->qp_num);
1760
1761         ntb_db_set_mask(qp->ndev, qp_bit);
1762         tasklet_disable(&qp->rxc_db_work);
1763
1764         cancel_delayed_work_sync(&qp->link_work);
1765
1766         qp->cb_data = NULL;
1767         qp->rx_handler = NULL;
1768         qp->tx_handler = NULL;
1769         qp->event_handler = NULL;
1770
1771         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1772                 kfree(entry);
1773
1774         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
1775                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
1776                 kfree(entry);
1777         }
1778
1779         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
1780                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
1781                 kfree(entry);
1782         }
1783
1784         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1785                 kfree(entry);
1786
1787         qp->transport->qp_bitmap_free |= qp_bit;
1788
1789         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1790 }
1791 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1792
1793 /**
1794  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1795  * @qp: NTB queue to be freed
1796  * @len: pointer to variable to write enqueued buffers length
1797  *
1798  * Dequeues unused buffers from receive queue.  Should only be used during
1799  * shutdown of qp.
1800  *
1801  * RETURNS: NULL error value on error, or void* for success.
1802  */
1803 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1804 {
1805         struct ntb_queue_entry *entry;
1806         void *buf;
1807
1808         if (!qp || qp->client_ready)
1809                 return NULL;
1810
1811         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
1812         if (!entry)
1813                 return NULL;
1814
1815         buf = entry->cb_data;
1816         *len = entry->len;
1817
1818         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
1819
1820         return buf;
1821 }
1822 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1823
1824 /**
1825  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1826  * @qp: NTB transport layer queue the entry is to be enqueued on
1827  * @cb: per buffer pointer for callback function to use
1828  * @data: pointer to data buffer that incoming packets will be copied into
1829  * @len: length of the data buffer
1830  *
1831  * Enqueue a new receive buffer onto the transport queue into which a NTB
1832  * payload can be received into.
1833  *
1834  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1835  */
1836 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1837                              unsigned int len)
1838 {
1839         struct ntb_queue_entry *entry;
1840
1841         if (!qp)
1842                 return -EINVAL;
1843
1844         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
1845         if (!entry)
1846                 return -ENOMEM;
1847
1848         entry->cb_data = cb;
1849         entry->buf = data;
1850         entry->len = len;
1851         entry->flags = 0;
1852
1853         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
1854
1855         tasklet_schedule(&qp->rxc_db_work);
1856
1857         return 0;
1858 }
1859 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1860
1861 /**
1862  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1863  * @qp: NTB transport layer queue the entry is to be enqueued on
1864  * @cb: per buffer pointer for callback function to use
1865  * @data: pointer to data buffer that will be sent
1866  * @len: length of the data buffer
1867  *
1868  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1869  * payload will be transmitted.  This assumes that a lock is being held to
1870  * serialize access to the qp.
1871  *
1872  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1873  */
1874 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1875                              unsigned int len)
1876 {
1877         struct ntb_queue_entry *entry;
1878         int rc;
1879
1880         if (!qp || !qp->link_is_up || !len)
1881                 return -EINVAL;
1882
1883         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1884         if (!entry) {
1885                 qp->tx_err_no_buf++;
1886                 return -EBUSY;
1887         }
1888
1889         entry->cb_data = cb;
1890         entry->buf = data;
1891         entry->len = len;
1892         entry->flags = 0;
1893
1894         rc = ntb_process_tx(qp, entry);
1895         if (rc)
1896                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1897                              &qp->tx_free_q);
1898
1899         return rc;
1900 }
1901 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1902
1903 /**
1904  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1905  * @qp: NTB transport layer queue to be enabled
1906  *
1907  * Notify NTB transport layer of client readiness to use queue
1908  */
1909 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1910 {
1911         if (!qp)
1912                 return;
1913
1914         qp->client_ready = true;
1915
1916         if (qp->transport->link_is_up)
1917                 schedule_delayed_work(&qp->link_work, 0);
1918 }
1919 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1920
1921 /**
1922  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1923  * @qp: NTB transport layer queue to be disabled
1924  *
1925  * Notify NTB transport layer of client's desire to no longer receive data on
1926  * transport queue specified.  It is the client's responsibility to ensure all
1927  * entries on queue are purged or otherwise handled appropriately.
1928  */
1929 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1930 {
1931         int val;
1932
1933         if (!qp)
1934                 return;
1935
1936         qp->client_ready = false;
1937
1938         val = ntb_spad_read(qp->ndev, QP_LINKS);
1939
1940         ntb_peer_spad_write(qp->ndev, QP_LINKS,
1941                             val & ~BIT(qp->qp_num));
1942
1943         if (qp->link_is_up)
1944                 ntb_send_link_down(qp);
1945         else
1946                 cancel_delayed_work_sync(&qp->link_work);
1947 }
1948 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1949
1950 /**
1951  * ntb_transport_link_query - Query transport link state
1952  * @qp: NTB transport layer queue to be queried
1953  *
1954  * Query connectivity to the remote system of the NTB transport queue
1955  *
1956  * RETURNS: true for link up or false for link down
1957  */
1958 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1959 {
1960         if (!qp)
1961                 return false;
1962
1963         return qp->link_is_up;
1964 }
1965 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1966
1967 /**
1968  * ntb_transport_qp_num - Query the qp number
1969  * @qp: NTB transport layer queue to be queried
1970  *
1971  * Query qp number of the NTB transport queue
1972  *
1973  * RETURNS: a zero based number specifying the qp number
1974  */
1975 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1976 {
1977         if (!qp)
1978                 return 0;
1979
1980         return qp->qp_num;
1981 }
1982 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1983
1984 /**
1985  * ntb_transport_max_size - Query the max payload size of a qp
1986  * @qp: NTB transport layer queue to be queried
1987  *
1988  * Query the maximum payload size permissible on the given qp
1989  *
1990  * RETURNS: the max payload size of a qp
1991  */
1992 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1993 {
1994         unsigned int max_size;
1995         unsigned int copy_align;
1996         struct dma_chan *rx_chan, *tx_chan;
1997
1998         if (!qp)
1999                 return 0;
2000
2001         rx_chan = qp->rx_dma_chan;
2002         tx_chan = qp->tx_dma_chan;
2003
2004         copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
2005                          tx_chan ? tx_chan->device->copy_align : 0);
2006
2007         /* If DMA engine usage is possible, try to find the max size for that */
2008         max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
2009         max_size = round_down(max_size, 1 << copy_align);
2010
2011         return max_size;
2012 }
2013 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
2014
2015 unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
2016 {
2017         unsigned int head = qp->tx_index;
2018         unsigned int tail = qp->remote_rx_info->entry;
2019
2020         return tail > head ? tail - head : qp->tx_max_entry + tail - head;
2021 }
2022 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
2023
2024 static void ntb_transport_doorbell_callback(void *data, int vector)
2025 {
2026         struct ntb_transport_ctx *nt = data;
2027         struct ntb_transport_qp *qp;
2028         u64 db_bits;
2029         unsigned int qp_num;
2030
2031         db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
2032                    ntb_db_vector_mask(nt->ndev, vector));
2033
2034         while (db_bits) {
2035                 qp_num = __ffs(db_bits);
2036                 qp = &nt->qp_vec[qp_num];
2037
2038                 tasklet_schedule(&qp->rxc_db_work);
2039
2040                 db_bits &= ~BIT_ULL(qp_num);
2041         }
2042 }
2043
2044 static const struct ntb_ctx_ops ntb_transport_ops = {
2045         .link_event = ntb_transport_event_callback,
2046         .db_event = ntb_transport_doorbell_callback,
2047 };
2048
2049 static struct ntb_client ntb_transport_client = {
2050         .ops = {
2051                 .probe = ntb_transport_probe,
2052                 .remove = ntb_transport_free,
2053         },
2054 };
2055
2056 static int __init ntb_transport_init(void)
2057 {
2058         int rc;
2059
2060         pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2061
2062         if (debugfs_initialized())
2063                 nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2064
2065         rc = bus_register(&ntb_transport_bus);
2066         if (rc)
2067                 goto err_bus;
2068
2069         rc = ntb_register_client(&ntb_transport_client);
2070         if (rc)
2071                 goto err_client;
2072
2073         return 0;
2074
2075 err_client:
2076         bus_unregister(&ntb_transport_bus);
2077 err_bus:
2078         debugfs_remove_recursive(nt_debugfs_dir);
2079         return rc;
2080 }
2081 module_init(ntb_transport_init);
2082
2083 static void __exit ntb_transport_exit(void)
2084 {
2085         debugfs_remove_recursive(nt_debugfs_dir);
2086
2087         ntb_unregister_client(&ntb_transport_client);
2088         bus_unregister(&ntb_transport_bus);
2089 }
2090 module_exit(ntb_transport_exit);