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 *dma_chan;
 123
 124         bool client_ready;
 125         bool link_is_up;
 126
 127         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 128         u64 qp_bit;
 129
 130         struct ntb_rx_info __iomem *rx_info;
 131         struct ntb_rx_info *remote_rx_info;
 132
 133         void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 134                            void *data, int len);
 135         struct list_head tx_free_q;
 136         spinlock_t ntb_tx_free_q_lock;
 137         void __iomem *tx_mw;
 138         dma_addr_t tx_mw_phys;
 139         unsigned int tx_index;
 140         unsigned int tx_max_entry;
 141         unsigned int tx_max_frame;
 142
 143         void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 144                            void *data, int len);
 145         struct list_head rx_pend_q;
 146         struct list_head rx_free_q;
 147         spinlock_t ntb_rx_pend_q_lock;
 148         spinlock_t ntb_rx_free_q_lock;
 149         void *rx_buff;
 150         unsigned int rx_index;
 151         unsigned int rx_max_entry;
 152         unsigned int rx_max_frame;
 153         dma_cookie_t last_cookie;
 154         struct tasklet_struct rxc_db_work;
 155
 156         void (*event_handler)(void *data, int status);
 157         struct delayed_work link_work;
 158         struct work_struct link_cleanup;
 159
 160         struct dentry *debugfs_dir;
 161         struct dentry *debugfs_stats;
 162
 163         /* Stats */
 164         u64 rx_bytes;
 165         u64 rx_pkts;
 166         u64 rx_ring_empty;
 167         u64 rx_err_no_buf;
 168         u64 rx_err_oflow;
 169         u64 rx_err_ver;
 170         u64 rx_memcpy;
 171         u64 rx_async;
 172         u64 tx_bytes;
 173         u64 tx_pkts;
 174         u64 tx_ring_full;
 175         u64 tx_err_no_buf;
 176         u64 tx_memcpy;
 177         u64 tx_async;
 178 };
 179
 180 struct ntb_transport_mw {
 181         phys_addr_t phys_addr;
 182         resource_size_t phys_size;
 183         resource_size_t xlat_align;
 184         resource_size_t xlat_align_size;
 185         void __iomem *vbase;
 186         size_t xlat_size;
 187         size_t buff_size;
 188         void *virt_addr;
 189         dma_addr_t dma_addr;
 190 };
 191
 192 struct ntb_transport_client_dev {
 193         struct list_head entry;
 194         struct ntb_transport_ctx *nt;
 195         struct device dev;
 196 };
 197
 198 struct ntb_transport_ctx {
 199         struct list_head entry;
 200         struct list_head client_devs;
 201
 202         struct ntb_dev *ndev;
 203
 204         struct ntb_transport_mw *mw_vec;
 205         struct ntb_transport_qp *qp_vec;
 206         unsigned int mw_count;
 207         unsigned int qp_count;
 208         u64 qp_bitmap;
 209         u64 qp_bitmap_free;
 210
 211         bool link_is_up;
 212         struct delayed_work link_work;
 213         struct work_struct link_cleanup;
 214 };
 215
 216 enum {
 217         DESC_DONE_FLAG = BIT(0),
 218         LINK_DOWN_FLAG = BIT(1),
 219 };
 220
 221 struct ntb_payload_header {
 222         unsigned int ver;
 223         unsigned int len;
 224         unsigned int flags;
 225 };
 226
 227 enum {
 228         VERSION = 0,
 229         QP_LINKS,
 230         NUM_QPS,
 231         NUM_MWS,
 232         MW0_SZ_HIGH,
 233         MW0_SZ_LOW,
 234         MW1_SZ_HIGH,
 235         MW1_SZ_LOW,
 236         MAX_SPAD,
 237 };
 238
 239 #define dev_client_dev(__dev) \
 240         container_of((__dev), struct ntb_transport_client_dev, dev)
 241
 242 #define drv_client(__drv) \
 243         container_of((__drv), struct ntb_transport_client, driver)
 244
 245 #define QP_TO_MW(nt, qp)        ((qp) % nt->mw_count)
 246 #define NTB_QP_DEF_NUM_ENTRIES  100
 247 #define NTB_LINK_DOWN_TIMEOUT   10
 248
 249 static void ntb_transport_rxc_db(unsigned long data);
 250 static const struct ntb_ctx_ops ntb_transport_ops;
 251 static struct ntb_client ntb_transport_client;
 252
 253 static int ntb_transport_bus_match(struct device *dev,
 254                                    struct device_driver *drv)
 255 {
 256         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 257 }
 258
 259 static int ntb_transport_bus_probe(struct device *dev)
 260 {
 261         const struct ntb_transport_client *client;
 262         int rc = -EINVAL;
 263
 264         get_device(dev);
 265
 266         client = drv_client(dev->driver);
 267         rc = client->probe(dev);
 268         if (rc)
 269                 put_device(dev);
 270
 271         return rc;
 272 }
 273
 274 static int ntb_transport_bus_remove(struct device *dev)
 275 {
 276         const struct ntb_transport_client *client;
 277
 278         client = drv_client(dev->driver);
 279         client->remove(dev);
 280
 281         put_device(dev);
 282
 283         return 0;
 284 }
 285
 286 static struct bus_type ntb_transport_bus = {
 287         .name = "ntb_transport",
 288         .match = ntb_transport_bus_match,
 289         .probe = ntb_transport_bus_probe,
 290         .remove = ntb_transport_bus_remove,
 291 };
 292
 293 static LIST_HEAD(ntb_transport_list);
 294
 295 static int ntb_bus_init(struct ntb_transport_ctx *nt)
 296 {
 297         list_add(&nt->entry, &ntb_transport_list);
 298         return 0;
 299 }
 300
 301 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
 302 {
 303         struct ntb_transport_client_dev *client_dev, *cd;
 304
 305         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 306                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 307                         dev_name(&client_dev->dev));
 308                 list_del(&client_dev->entry);
 309                 device_unregister(&client_dev->dev);
 310         }
 311
 312         list_del(&nt->entry);
 313 }
 314
 315 static void ntb_transport_client_release(struct device *dev)
 316 {
 317         struct ntb_transport_client_dev *client_dev;
 318
 319         client_dev = dev_client_dev(dev);
 320         kfree(client_dev);
 321 }
 322
 323 /**
 324  * ntb_transport_unregister_client_dev - Unregister NTB client device
 325  * @device_name: Name of NTB client device
 326  *
 327  * Unregister an NTB client device with the NTB transport layer
 328  */
 329 void ntb_transport_unregister_client_dev(char *device_name)
 330 {
 331         struct ntb_transport_client_dev *client, *cd;
 332         struct ntb_transport_ctx *nt;
 333
 334         list_for_each_entry(nt, &ntb_transport_list, entry)
 335                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 336                         if (!strncmp(dev_name(&client->dev), device_name,
 337                                      strlen(device_name))) {
 338                                 list_del(&client->entry);
 339                                 device_unregister(&client->dev);
 340                         }
 341 }
 342 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
 343
 344 /**
 345  * ntb_transport_register_client_dev - Register NTB client device
 346  * @device_name: Name of NTB client device
 347  *
 348  * Register an NTB client device with the NTB transport layer
 349  */
 350 int ntb_transport_register_client_dev(char *device_name)
 351 {
 352         struct ntb_transport_client_dev *client_dev;
 353         struct ntb_transport_ctx *nt;
 354         int node;
 355         int rc, i = 0;
 356
 357         if (list_empty(&ntb_transport_list))
 358                 return -ENODEV;
 359
 360         list_for_each_entry(nt, &ntb_transport_list, entry) {
 361                 struct device *dev;
 362
 363                 node = dev_to_node(&nt->ndev->dev);
 364
 365                 client_dev = kzalloc_node(sizeof(*client_dev),
 366                                           GFP_KERNEL, node);
 367                 if (!client_dev) {
 368                         rc = -ENOMEM;
 369                         goto err;
 370                 }
 371
 372                 dev = &client_dev->dev;
 373
 374                 /* setup and register client devices */
 375                 dev_set_name(dev, "%s%d", device_name, i);
 376                 dev->bus = &ntb_transport_bus;
 377                 dev->release = ntb_transport_client_release;
 378                 dev->parent = &nt->ndev->dev;
 379
 380                 rc = device_register(dev);
 381                 if (rc) {
 382                         kfree(client_dev);
 383                         goto err;
 384                 }
 385
 386                 list_add_tail(&client_dev->entry, &nt->client_devs);
 387                 i++;
 388         }
 389
 390         return 0;
 391
 392 err:
 393         ntb_transport_unregister_client_dev(device_name);
 394
 395         return rc;
 396 }
 397 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
 398
 399 /**
 400  * ntb_transport_register_client - Register NTB client driver
 401  * @drv: NTB client driver to be registered
 402  *
 403  * Register an NTB client driver with the NTB transport layer
 404  *
 405  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 406  */
 407 int ntb_transport_register_client(struct ntb_transport_client *drv)
 408 {
 409         drv->driver.bus = &ntb_transport_bus;
 410
 411         if (list_empty(&ntb_transport_list))
 412                 return -ENODEV;
 413
 414         return driver_register(&drv->driver);
 415 }
 416 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
 417
 418 /**
 419  * ntb_transport_unregister_client - Unregister NTB client driver
 420  * @drv: NTB client driver to be unregistered
 421  *
 422  * Unregister an NTB client driver with the NTB transport layer
 423  *
 424  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 425  */
 426 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
 427 {
 428         driver_unregister(&drv->driver);
 429 }
 430 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
 431
 432 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 433                             loff_t *offp)
 434 {
 435         struct ntb_transport_qp *qp;
 436         char *buf;
 437         ssize_t ret, out_offset, out_count;
 438
 439         out_count = 1000;
 440
 441         buf = kmalloc(out_count, GFP_KERNEL);
 442         if (!buf)
 443                 return -ENOMEM;
 444
 445         qp = filp->private_data;
 446         out_offset = 0;
 447         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 448                                "NTB QP stats\n");
 449         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 450                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 451         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 452                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 453         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 454                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
 455         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 456                                "rx_async - \t%llu\n", qp->rx_async);
 457         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 458                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 459         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 460                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 461         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 462                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 463         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 464                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 465         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 466                                "rx_buff - \t%p\n", qp->rx_buff);
 467         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 468                                "rx_index - \t%u\n", qp->rx_index);
 469         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 470                                "rx_max_entry - \t%u\n", qp->rx_max_entry);
 471
 472         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 473                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 474         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 475                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 476         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 477                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
 478         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 479                                "tx_async - \t%llu\n", qp->tx_async);
 480         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 481                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 482         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 483                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 484         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 485                                "tx_mw - \t%p\n", qp->tx_mw);
 486         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 487                                "tx_index - \t%u\n", qp->tx_index);
 488         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 489                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
 490
 491         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 492                                "\nQP Link %s\n",
 493                                qp->link_is_up ? "Up" : "Down");
 494         if (out_offset > out_count)
 495                 out_offset = out_count;
 496
 497         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 498         kfree(buf);
 499         return ret;
 500 }
 501
 502 static const struct file_operations ntb_qp_debugfs_stats = {
 503         .owner = THIS_MODULE,
 504         .open = simple_open,
 505         .read = debugfs_read,
 506 };
 507
 508 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 509                          struct list_head *list)
 510 {
 511         unsigned long flags;
 512
 513         spin_lock_irqsave(lock, flags);
 514         list_add_tail(entry, list);
 515         spin_unlock_irqrestore(lock, flags);
 516 }
 517
 518 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 519                                            struct list_head *list)
 520 {
 521         struct ntb_queue_entry *entry;
 522         unsigned long flags;
 523
 524         spin_lock_irqsave(lock, flags);
 525         if (list_empty(list)) {
 526                 entry = NULL;
 527                 goto out;
 528         }
 529         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 530         list_del(&entry->entry);
 531 out:
 532         spin_unlock_irqrestore(lock, flags);
 533
 534         return entry;
 535 }
 536
 537 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 538                                      unsigned int qp_num)
 539 {
 540         struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
 541         struct ntb_transport_mw *mw;
 542         unsigned int rx_size, num_qps_mw;
 543         unsigned int mw_num, mw_count, qp_count;
 544         unsigned int i;
 545
 546         mw_count = nt->mw_count;
 547         qp_count = nt->qp_count;
 548
 549         mw_num = QP_TO_MW(nt, qp_num);
 550         mw = &nt->mw_vec[mw_num];
 551
 552         if (!mw->virt_addr)
 553                 return -ENOMEM;
 554
 555         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 556                 num_qps_mw = qp_count / mw_count + 1;
 557         else
 558                 num_qps_mw = qp_count / mw_count;
 559
 560         rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
 561         qp->rx_buff = mw->virt_addr + rx_size * qp_num / mw_count;
 562         rx_size -= sizeof(struct ntb_rx_info);
 563
 564         qp->remote_rx_info = qp->rx_buff + rx_size;
 565
 566         /* Due to housekeeping, there must be atleast 2 buffs */
 567         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
 568         qp->rx_max_entry = rx_size / qp->rx_max_frame;
 569         qp->rx_index = 0;
 570
 571         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
 572
 573         /* setup the hdr offsets with 0's */
 574         for (i = 0; i < qp->rx_max_entry; i++) {
 575                 void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
 576                                 sizeof(struct ntb_payload_header));
 577                 memset(offset, 0, sizeof(struct ntb_payload_header));
 578         }
 579
 580         qp->rx_pkts = 0;
 581         qp->tx_pkts = 0;
 582         qp->tx_index = 0;
 583
 584         return 0;
 585 }
 586
 587 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 588 {
 589         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 590         struct pci_dev *pdev = nt->ndev->pdev;
 591
 592         if (!mw->virt_addr)
 593                 return;
 594
 595         ntb_mw_clear_trans(nt->ndev, num_mw);
 596         dma_free_coherent(&pdev->dev, mw->buff_size,
 597                           mw->virt_addr, mw->dma_addr);
 598         mw->xlat_size = 0;
 599         mw->buff_size = 0;
 600         mw->virt_addr = NULL;
 601 }
 602
 603 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 604                       unsigned int size)
 605 {
 606         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 607         struct pci_dev *pdev = nt->ndev->pdev;
 608         unsigned int xlat_size, buff_size;
 609         int rc;
 610
 611         xlat_size = round_up(size, mw->xlat_align_size);
 612         buff_size = round_up(size, mw->xlat_align);
 613
 614         /* No need to re-setup */
 615         if (mw->xlat_size == xlat_size)
 616                 return 0;
 617
 618         if (mw->buff_size)
 619                 ntb_free_mw(nt, num_mw);
 620
 621         /* Alloc memory for receiving data.  Must be aligned */
 622         mw->xlat_size = xlat_size;
 623         mw->buff_size = buff_size;
 624
 625         mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
 626                                            &mw->dma_addr, GFP_KERNEL);
 627         if (!mw->virt_addr) {
 628                 mw->xlat_size = 0;
 629                 mw->buff_size = 0;
 630                 dev_err(&pdev->dev, "Unable to alloc MW buff of size %d\n",
 631                         buff_size);
 632                 return -ENOMEM;
 633         }
 634
 635         /*
 636          * we must ensure that the memory address allocated is BAR size
 637          * aligned in order for the XLAT register to take the value. This
 638          * is a requirement of the hardware. It is recommended to setup CMA
 639          * for BAR sizes equal or greater than 4MB.
 640          */
 641         if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
 642                 dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
 643                         &mw->dma_addr);
 644                 ntb_free_mw(nt, num_mw);
 645                 return -ENOMEM;
 646         }
 647
 648         /* Notify HW the memory location of the receive buffer */
 649         rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
 650         if (rc) {
 651                 dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
 652                 ntb_free_mw(nt, num_mw);
 653                 return -EIO;
 654         }
 655
 656         return 0;
 657 }
 658
 659 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 660 {
 661         qp->link_is_up = false;
 662
 663         qp->tx_index = 0;
 664         qp->rx_index = 0;
 665         qp->rx_bytes = 0;
 666         qp->rx_pkts = 0;
 667         qp->rx_ring_empty = 0;
 668         qp->rx_err_no_buf = 0;
 669         qp->rx_err_oflow = 0;
 670         qp->rx_err_ver = 0;
 671         qp->rx_memcpy = 0;
 672         qp->rx_async = 0;
 673         qp->tx_bytes = 0;
 674         qp->tx_pkts = 0;
 675         qp->tx_ring_full = 0;
 676         qp->tx_err_no_buf = 0;
 677         qp->tx_memcpy = 0;
 678         qp->tx_async = 0;
 679 }
 680
 681 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
 682 {
 683         struct ntb_transport_ctx *nt = qp->transport;
 684         struct pci_dev *pdev = nt->ndev->pdev;
 685
 686         dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
 687
 688         cancel_delayed_work_sync(&qp->link_work);
 689         ntb_qp_link_down_reset(qp);
 690
 691         if (qp->event_handler)
 692                 qp->event_handler(qp->cb_data, qp->link_is_up);
 693 }
 694
 695 static void ntb_qp_link_cleanup_work(struct work_struct *work)
 696 {
 697         struct ntb_transport_qp *qp = container_of(work,
 698                                                    struct ntb_transport_qp,
 699                                                    link_cleanup);
 700         struct ntb_transport_ctx *nt = qp->transport;
 701
 702         ntb_qp_link_cleanup(qp);
 703
 704         if (nt->link_is_up)
 705                 schedule_delayed_work(&qp->link_work,
 706                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 707 }
 708
 709 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 710 {
 711         schedule_work(&qp->link_cleanup);
 712 }
 713
 714 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 715 {
 716         struct ntb_transport_qp *qp;
 717         u64 qp_bitmap_alloc;
 718         int i;
 719
 720         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
 721
 722         /* Pass along the info to any clients */
 723         for (i = 0; i < nt->qp_count; i++)
 724                 if (qp_bitmap_alloc & BIT_ULL(i)) {
 725                         qp = &nt->qp_vec[i];
 726                         ntb_qp_link_cleanup(qp);
 727                         cancel_work_sync(&qp->link_cleanup);
 728                         cancel_delayed_work_sync(&qp->link_work);
 729                 }
 730
 731         if (!nt->link_is_up)
 732                 cancel_delayed_work_sync(&nt->link_work);
 733
 734         /* The scratchpad registers keep the values if the remote side
 735          * goes down, blast them now to give them a sane value the next
 736          * time they are accessed
 737          */
 738         for (i = 0; i < MAX_SPAD; i++)
 739                 ntb_spad_write(nt->ndev, i, 0);
 740 }
 741
 742 static void ntb_transport_link_cleanup_work(struct work_struct *work)
 743 {
 744         struct ntb_transport_ctx *nt =
 745                 container_of(work, struct ntb_transport_ctx, link_cleanup);
 746
 747         ntb_transport_link_cleanup(nt);
 748 }
 749
 750 static void ntb_transport_event_callback(void *data)
 751 {
 752         struct ntb_transport_ctx *nt = data;
 753
 754         if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
 755                 schedule_delayed_work(&nt->link_work, 0);
 756         else
 757                 schedule_work(&nt->link_cleanup);
 758 }
 759
 760 static void ntb_transport_link_work(struct work_struct *work)
 761 {
 762         struct ntb_transport_ctx *nt =
 763                 container_of(work, struct ntb_transport_ctx, link_work.work);
 764         struct ntb_dev *ndev = nt->ndev;
 765         struct pci_dev *pdev = ndev->pdev;
 766         resource_size_t size;
 767         u32 val;
 768         int rc, i, spad;
 769
 770         /* send the local info, in the opposite order of the way we read it */
 771         for (i = 0; i < nt->mw_count; i++) {
 772                 size = nt->mw_vec[i].phys_size;
 773
 774                 if (max_mw_size && size > max_mw_size)
 775                         size = max_mw_size;
 776
 777                 spad = MW0_SZ_HIGH + (i * 2);
 778                 ntb_peer_spad_write(ndev, spad, (u32)(size >> 32));
 779
 780                 spad = MW0_SZ_LOW + (i * 2);
 781                 ntb_peer_spad_write(ndev, spad, (u32)size);
 782         }
 783
 784         ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
 785
 786         ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
 787
 788         ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
 789
 790         /* Query the remote side for its info */
 791         val = ntb_spad_read(ndev, VERSION);
 792         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 793         if (val != NTB_TRANSPORT_VERSION)
 794                 goto out;
 795
 796         val = ntb_spad_read(ndev, NUM_QPS);
 797         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 798         if (val != nt->qp_count)
 799                 goto out;
 800
 801         val = ntb_spad_read(ndev, NUM_MWS);
 802         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
 803         if (val != nt->mw_count)
 804                 goto out;
 805
 806         for (i = 0; i < nt->mw_count; i++) {
 807                 u64 val64;
 808
 809                 val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
 810                 val64 = (u64)val << 32;
 811
 812                 val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
 813                 val64 |= val;
 814
 815                 dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
 816
 817                 rc = ntb_set_mw(nt, i, val64);
 818                 if (rc)
 819                         goto out1;
 820         }
 821
 822         nt->link_is_up = true;
 823
 824         for (i = 0; i < nt->qp_count; i++) {
 825                 struct ntb_transport_qp *qp = &nt->qp_vec[i];
 826
 827                 ntb_transport_setup_qp_mw(nt, i);
 828
 829                 if (qp->client_ready)
 830                         schedule_delayed_work(&qp->link_work, 0);
 831         }
 832
 833         return;
 834
 835 out1:
 836         for (i = 0; i < nt->mw_count; i++)
 837                 ntb_free_mw(nt, i);
 838 out:
 839         if (ntb_link_is_up(ndev, NULL, NULL) == 1)
 840                 schedule_delayed_work(&nt->link_work,
 841                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 842 }
 843
 844 static void ntb_qp_link_work(struct work_struct *work)
 845 {
 846         struct ntb_transport_qp *qp = container_of(work,
 847                                                    struct ntb_transport_qp,
 848                                                    link_work.work);
 849         struct pci_dev *pdev = qp->ndev->pdev;
 850         struct ntb_transport_ctx *nt = qp->transport;
 851         int val;
 852
 853         WARN_ON(!nt->link_is_up);
 854
 855         val = ntb_spad_read(nt->ndev, QP_LINKS);
 856
 857         ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
 858
 859         /* query remote spad for qp ready bits */
 860         ntb_peer_spad_read(nt->ndev, QP_LINKS);
 861         dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
 862
 863         /* See if the remote side is up */
 864         if (val & BIT(qp->qp_num)) {
 865                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 866                 qp->link_is_up = true;
 867
 868                 if (qp->event_handler)
 869                         qp->event_handler(qp->cb_data, qp->link_is_up);
 870         } else if (nt->link_is_up)
 871                 schedule_delayed_work(&qp->link_work,
 872                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 873 }
 874
 875 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 876                                     unsigned int qp_num)
 877 {
 878         struct ntb_transport_qp *qp;
 879         struct ntb_transport_mw *mw;
 880         phys_addr_t mw_base;
 881         resource_size_t mw_size;
 882         unsigned int num_qps_mw, tx_size;
 883         unsigned int mw_num, mw_count, qp_count;
 884         u64 qp_offset;
 885
 886         mw_count = nt->mw_count;
 887         qp_count = nt->qp_count;
 888
 889         mw_num = QP_TO_MW(nt, qp_num);
 890         mw = &nt->mw_vec[mw_num];
 891
 892         qp = &nt->qp_vec[qp_num];
 893         qp->qp_num = qp_num;
 894         qp->transport = nt;
 895         qp->ndev = nt->ndev;
 896         qp->client_ready = false;
 897         qp->event_handler = NULL;
 898         ntb_qp_link_down_reset(qp);
 899
 900         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 901                 num_qps_mw = qp_count / mw_count + 1;
 902         else
 903                 num_qps_mw = qp_count / mw_count;
 904
 905         mw_base = nt->mw_vec[mw_num].phys_addr;
 906         mw_size = nt->mw_vec[mw_num].phys_size;
 907
 908         tx_size = (unsigned int)mw_size / num_qps_mw;
 909         qp_offset = tx_size * qp_num / mw_count;
 910
 911         qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
 912         if (!qp->tx_mw)
 913                 return -EINVAL;
 914
 915         qp->tx_mw_phys = mw_base + qp_offset;
 916         if (!qp->tx_mw_phys)
 917                 return -EINVAL;
 918
 919         tx_size -= sizeof(struct ntb_rx_info);
 920         qp->rx_info = qp->tx_mw + tx_size;
 921
 922         /* Due to housekeeping, there must be atleast 2 buffs */
 923         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
 924         qp->tx_max_entry = tx_size / qp->tx_max_frame;
 925
 926         if (nt_debugfs_dir) {
 927                 char debugfs_name[4];
 928
 929                 snprintf(debugfs_name, 4, "qp%d", qp_num);
 930                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 931                                                      nt_debugfs_dir);
 932
 933                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
 934                                                         qp->debugfs_dir, qp,
 935                                                         &ntb_qp_debugfs_stats);
 936         } else {
 937                 qp->debugfs_dir = NULL;
 938                 qp->debugfs_stats = NULL;
 939         }
 940
 941         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
 942         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
 943
 944         spin_lock_init(&qp->ntb_rx_pend_q_lock);
 945         spin_lock_init(&qp->ntb_rx_free_q_lock);
 946         spin_lock_init(&qp->ntb_tx_free_q_lock);
 947
 948         INIT_LIST_HEAD(&qp->rx_pend_q);
 949         INIT_LIST_HEAD(&qp->rx_free_q);
 950         INIT_LIST_HEAD(&qp->tx_free_q);
 951
 952         tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
 953                      (unsigned long)qp);
 954
 955         return 0;
 956 }
 957
 958 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 959 {
 960         struct ntb_transport_ctx *nt;
 961         struct ntb_transport_mw *mw;
 962         unsigned int mw_count, qp_count;
 963         u64 qp_bitmap;
 964         int node;
 965         int rc, i;
 966
 967         if (ntb_db_is_unsafe(ndev))
 968                 dev_dbg(&ndev->dev,
 969                         "doorbell is unsafe, proceed anyway...\n");
 970         if (ntb_spad_is_unsafe(ndev))
 971                 dev_dbg(&ndev->dev,
 972                         "scratchpad is unsafe, proceed anyway...\n");
 973
 974         node = dev_to_node(&ndev->dev);
 975
 976         nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
 977         if (!nt)
 978                 return -ENOMEM;
 979
 980         nt->ndev = ndev;
 981
 982         mw_count = ntb_mw_count(ndev);
 983
 984         nt->mw_count = mw_count;
 985
 986         nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
 987                                   GFP_KERNEL, node);
 988         if (!nt->mw_vec) {
 989                 rc = -ENOMEM;
 990                 goto err;
 991         }
 992
 993         for (i = 0; i < mw_count; i++) {
 994                 mw = &nt->mw_vec[i];
 995
 996                 rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
 997                                       &mw->xlat_align, &mw->xlat_align_size);
 998                 if (rc)
 999                         goto err1;
1000
1001                 mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1002                 if (!mw->vbase) {
1003                         rc = -ENOMEM;
1004                         goto err1;
1005                 }
1006
1007                 mw->buff_size = 0;
1008                 mw->xlat_size = 0;
1009                 mw->virt_addr = NULL;
1010                 mw->dma_addr = 0;
1011         }
1012
1013         qp_bitmap = ntb_db_valid_mask(ndev);
1014
1015         qp_count = ilog2(qp_bitmap);
1016         if (max_num_clients && max_num_clients < qp_count)
1017                 qp_count = max_num_clients;
1018         else if (mw_count < qp_count)
1019                 qp_count = mw_count;
1020
1021         qp_bitmap &= BIT_ULL(qp_count) - 1;
1022
1023         nt->qp_count = qp_count;
1024         nt->qp_bitmap = qp_bitmap;
1025         nt->qp_bitmap_free = qp_bitmap;
1026
1027         nt->qp_vec = kzalloc_node(qp_count * sizeof(*nt->qp_vec),
1028                                   GFP_KERNEL, node);
1029         if (!nt->qp_vec) {
1030                 rc = -ENOMEM;
1031                 goto err2;
1032         }
1033
1034         for (i = 0; i < qp_count; i++) {
1035                 rc = ntb_transport_init_queue(nt, i);
1036                 if (rc)
1037                         goto err3;
1038         }
1039
1040         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1041         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1042
1043         rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1044         if (rc)
1045                 goto err3;
1046
1047         INIT_LIST_HEAD(&nt->client_devs);
1048         rc = ntb_bus_init(nt);
1049         if (rc)
1050                 goto err4;
1051
1052         nt->link_is_up = false;
1053         ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1054         ntb_link_event(ndev);
1055
1056         return 0;
1057
1058 err4:
1059         ntb_clear_ctx(ndev);
1060 err3:
1061         kfree(nt->qp_vec);
1062 err2:
1063         kfree(nt->mw_vec);
1064 err1:
1065         while (i--) {
1066                 mw = &nt->mw_vec[i];
1067                 iounmap(mw->vbase);
1068         }
1069 err:
1070         kfree(nt);
1071         return rc;
1072 }
1073
1074 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1075 {
1076         struct ntb_transport_ctx *nt = ndev->ctx;
1077         struct ntb_transport_qp *qp;
1078         u64 qp_bitmap_alloc;
1079         int i;
1080
1081         ntb_transport_link_cleanup(nt);
1082         cancel_work_sync(&nt->link_cleanup);
1083         cancel_delayed_work_sync(&nt->link_work);
1084
1085         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1086
1087         /* verify that all the qp's are freed */
1088         for (i = 0; i < nt->qp_count; i++) {
1089                 qp = &nt->qp_vec[i];
1090                 if (qp_bitmap_alloc & BIT_ULL(i))
1091                         ntb_transport_free_queue(qp);
1092                 debugfs_remove_recursive(qp->debugfs_dir);
1093         }
1094
1095         ntb_link_disable(ndev);
1096         ntb_clear_ctx(ndev);
1097
1098         ntb_bus_remove(nt);
1099
1100         for (i = nt->mw_count; i--; ) {
1101                 ntb_free_mw(nt, i);
1102                 iounmap(nt->mw_vec[i].vbase);
1103         }
1104
1105         kfree(nt->qp_vec);
1106         kfree(nt->mw_vec);
1107         kfree(nt);
1108 }
1109
1110 static void ntb_rx_copy_callback(void *data)
1111 {
1112         struct ntb_queue_entry *entry = data;
1113         struct ntb_transport_qp *qp = entry->qp;
1114         void *cb_data = entry->cb_data;
1115         unsigned int len = entry->len;
1116         struct ntb_payload_header *hdr = entry->rx_hdr;
1117
1118         hdr->flags = 0;
1119
1120         iowrite32(entry->index, &qp->rx_info->entry);
1121
1122         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1123
1124         if (qp->rx_handler && qp->client_ready)
1125                 qp->rx_handler(qp, qp->cb_data, cb_data, len);
1126 }
1127
1128 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1129 {
1130         void *buf = entry->buf;
1131         size_t len = entry->len;
1132
1133         memcpy(buf, offset, len);
1134
1135         /* Ensure that the data is fully copied out before clearing the flag */
1136         wmb();
1137
1138         ntb_rx_copy_callback(entry);
1139 }
1140
1141 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
1142                          size_t len)
1143 {
1144         struct dma_async_tx_descriptor *txd;
1145         struct ntb_transport_qp *qp = entry->qp;
1146         struct dma_chan *chan = qp->dma_chan;
1147         struct dma_device *device;
1148         size_t pay_off, buff_off;
1149         struct dmaengine_unmap_data *unmap;
1150         dma_cookie_t cookie;
1151         void *buf = entry->buf;
1152
1153         entry->len = len;
1154
1155         if (!chan)
1156                 goto err;
1157
1158         if (len < copy_bytes)
1159                 goto err_wait;
1160
1161         device = chan->device;
1162         pay_off = (size_t)offset & ~PAGE_MASK;
1163         buff_off = (size_t)buf & ~PAGE_MASK;
1164
1165         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1166                 goto err_wait;
1167
1168         unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1169         if (!unmap)
1170                 goto err_wait;
1171
1172         unmap->len = len;
1173         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1174                                       pay_off, len, DMA_TO_DEVICE);
1175         if (dma_mapping_error(device->dev, unmap->addr[0]))
1176                 goto err_get_unmap;
1177
1178         unmap->to_cnt = 1;
1179
1180         unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1181                                       buff_off, len, DMA_FROM_DEVICE);
1182         if (dma_mapping_error(device->dev, unmap->addr[1]))
1183                 goto err_get_unmap;
1184
1185         unmap->from_cnt = 1;
1186
1187         txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1188                                              unmap->addr[0], len,
1189                                              DMA_PREP_INTERRUPT);
1190         if (!txd)
1191                 goto err_get_unmap;
1192
1193         txd->callback = ntb_rx_copy_callback;
1194         txd->callback_param = entry;
1195         dma_set_unmap(txd, unmap);
1196
1197         cookie = dmaengine_submit(txd);
1198         if (dma_submit_error(cookie))
1199                 goto err_set_unmap;
1200
1201         dmaengine_unmap_put(unmap);
1202
1203         qp->last_cookie = cookie;
1204
1205         qp->rx_async++;
1206
1207         return;
1208
1209 err_set_unmap:
1210         dmaengine_unmap_put(unmap);
1211 err_get_unmap:
1212         dmaengine_unmap_put(unmap);
1213 err_wait:
1214         /* If the callbacks come out of order, the writing of the index to the
1215          * last completed will be out of order.  This may result in the
1216          * receive stalling forever.
1217          */
1218         dma_sync_wait(chan, qp->last_cookie);
1219 err:
1220         ntb_memcpy_rx(entry, offset);
1221         qp->rx_memcpy++;
1222 }
1223
1224 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1225 {
1226         struct ntb_payload_header *hdr;
1227         struct ntb_queue_entry *entry;
1228         void *offset;
1229         int rc;
1230
1231         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1232         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1233
1234         dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1235                 qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1236
1237         if (!(hdr->flags & DESC_DONE_FLAG)) {
1238                 dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1239                 qp->rx_ring_empty++;
1240                 return -EAGAIN;
1241         }
1242
1243         if (hdr->flags & LINK_DOWN_FLAG) {
1244                 dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1245                 ntb_qp_link_down(qp);
1246                 hdr->flags = 0;
1247                 return -EAGAIN;
1248         }
1249
1250         if (hdr->ver != (u32)qp->rx_pkts) {
1251                 dev_dbg(&qp->ndev->pdev->dev,
1252                         "version mismatch, expected %llu - got %u\n",
1253                         qp->rx_pkts, hdr->ver);
1254                 qp->rx_err_ver++;
1255                 return -EIO;
1256         }
1257
1258         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1259         if (!entry) {
1260                 dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1261                 qp->rx_err_no_buf++;
1262
1263                 rc = -ENOMEM;
1264                 goto err;
1265         }
1266
1267         if (hdr->len > entry->len) {
1268                 dev_dbg(&qp->ndev->pdev->dev,
1269                         "receive buffer overflow! Wanted %d got %d\n",
1270                         hdr->len, entry->len);
1271                 qp->rx_err_oflow++;
1272
1273                 rc = -EIO;
1274                 goto err;
1275         }
1276
1277         dev_dbg(&qp->ndev->pdev->dev,
1278                 "RX OK index %u ver %u size %d into buf size %d\n",
1279                 qp->rx_index, hdr->ver, hdr->len, entry->len);
1280
1281         qp->rx_bytes += hdr->len;
1282         qp->rx_pkts++;
1283
1284         entry->index = qp->rx_index;
1285         entry->rx_hdr = hdr;
1286
1287         ntb_async_rx(entry, offset, hdr->len);
1288
1289         qp->rx_index++;
1290         qp->rx_index %= qp->rx_max_entry;
1291
1292         return 0;
1293
1294 err:
1295         /* FIXME: if this syncrhonous update of the rx_index gets ahead of
1296          * asyncrhonous ntb_rx_copy_callback of previous entry, there are three
1297          * scenarios:
1298          *
1299          * 1) The peer might miss this update, but observe the update
1300          * from the memcpy completion callback.  In this case, the buffer will
1301          * not be freed on the peer to be reused for a different packet.  The
1302          * successful rx of a later packet would clear the condition, but the
1303          * condition could persist if several rx fail in a row.
1304          *
1305          * 2) The peer may observe this update before the asyncrhonous copy of
1306          * prior packets is completed.  The peer may overwrite the buffers of
1307          * the prior packets before they are copied.
1308          *
1309          * 3) Both: the peer may observe the update, and then observe the index
1310          * decrement by the asynchronous completion callback.  Who knows what
1311          * badness that will cause.
1312          */
1313         hdr->flags = 0;
1314         iowrite32(qp->rx_index, &qp->rx_info->entry);
1315
1316         return rc;
1317 }
1318
1319 static void ntb_transport_rxc_db(unsigned long data)
1320 {
1321         struct ntb_transport_qp *qp = (void *)data;
1322         int rc, i;
1323
1324         dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1325                 __func__, qp->qp_num);
1326
1327         /* Limit the number of packets processed in a single interrupt to
1328          * provide fairness to others
1329          */
1330         for (i = 0; i < qp->rx_max_entry; i++) {
1331                 rc = ntb_process_rxc(qp);
1332                 if (rc)
1333                         break;
1334         }
1335
1336         if (qp->dma_chan)
1337                 dma_async_issue_pending(qp->dma_chan);
1338
1339         if (i == qp->rx_max_entry) {
1340                 /* there is more work to do */
1341                 tasklet_schedule(&qp->rxc_db_work);
1342         } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1343                 /* the doorbell bit is set: clear it */
1344                 ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1345                 /* ntb_db_read ensures ntb_db_clear write is committed */
1346                 ntb_db_read(qp->ndev);
1347
1348                 /* an interrupt may have arrived between finishing
1349                  * ntb_process_rxc and clearing the doorbell bit:
1350                  * there might be some more work to do.
1351                  */
1352                 tasklet_schedule(&qp->rxc_db_work);
1353         }
1354 }
1355
1356 static void ntb_tx_copy_callback(void *data)
1357 {
1358         struct ntb_queue_entry *entry = data;
1359         struct ntb_transport_qp *qp = entry->qp;
1360         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1361
1362         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1363
1364         ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1365
1366         /* The entry length can only be zero if the packet is intended to be a
1367          * "link down" or similar.  Since no payload is being sent in these
1368          * cases, there is nothing to add to the completion queue.
1369          */
1370         if (entry->len > 0) {
1371                 qp->tx_bytes += entry->len;
1372
1373                 if (qp->tx_handler)
1374                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1375                                        entry->len);
1376         }
1377
1378         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1379 }
1380
1381 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1382 {
1383 #ifdef ARCH_HAS_NOCACHE_UACCESS
1384         /*
1385          * Using non-temporal mov to improve performance on non-cached
1386          * writes, even though we aren't actually copying from user space.
1387          */
1388         __copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1389 #else
1390         memcpy_toio(offset, entry->buf, entry->len);
1391 #endif
1392
1393         /* Ensure that the data is fully copied out before setting the flags */
1394         wmb();
1395
1396         ntb_tx_copy_callback(entry);
1397 }
1398
1399 static void ntb_async_tx(struct ntb_transport_qp *qp,
1400                          struct ntb_queue_entry *entry)
1401 {
1402         struct ntb_payload_header __iomem *hdr;
1403         struct dma_async_tx_descriptor *txd;
1404         struct dma_chan *chan = qp->dma_chan;
1405         struct dma_device *device;
1406         size_t dest_off, buff_off;
1407         struct dmaengine_unmap_data *unmap;
1408         dma_addr_t dest;
1409         dma_cookie_t cookie;
1410         void __iomem *offset;
1411         size_t len = entry->len;
1412         void *buf = entry->buf;
1413
1414         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1415         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1416         entry->tx_hdr = hdr;
1417
1418         iowrite32(entry->len, &hdr->len);
1419         iowrite32((u32)qp->tx_pkts, &hdr->ver);
1420
1421         if (!chan)
1422                 goto err;
1423
1424         if (len < copy_bytes)
1425                 goto err;
1426
1427         device = chan->device;
1428         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1429         buff_off = (size_t)buf & ~PAGE_MASK;
1430         dest_off = (size_t)dest & ~PAGE_MASK;
1431
1432         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1433                 goto err;
1434
1435         unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1436         if (!unmap)
1437                 goto err;
1438
1439         unmap->len = len;
1440         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1441                                       buff_off, len, DMA_TO_DEVICE);
1442         if (dma_mapping_error(device->dev, unmap->addr[0]))
1443                 goto err_get_unmap;
1444
1445         unmap->to_cnt = 1;
1446
1447         txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
1448                                              DMA_PREP_INTERRUPT);
1449         if (!txd)
1450                 goto err_get_unmap;
1451
1452         txd->callback = ntb_tx_copy_callback;
1453         txd->callback_param = entry;
1454         dma_set_unmap(txd, unmap);
1455
1456         cookie = dmaengine_submit(txd);
1457         if (dma_submit_error(cookie))
1458                 goto err_set_unmap;
1459
1460         dmaengine_unmap_put(unmap);
1461
1462         dma_async_issue_pending(chan);
1463         qp->tx_async++;
1464
1465         return;
1466 err_set_unmap:
1467         dmaengine_unmap_put(unmap);
1468 err_get_unmap:
1469         dmaengine_unmap_put(unmap);
1470 err:
1471         ntb_memcpy_tx(entry, offset);
1472         qp->tx_memcpy++;
1473 }
1474
1475 static int ntb_process_tx(struct ntb_transport_qp *qp,
1476                           struct ntb_queue_entry *entry)
1477 {
1478         if (qp->tx_index == qp->remote_rx_info->entry) {
1479                 qp->tx_ring_full++;
1480                 return -EAGAIN;
1481         }
1482
1483         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1484                 if (qp->tx_handler)
1485                         qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
1486
1487                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1488                              &qp->tx_free_q);
1489                 return 0;
1490         }
1491
1492         ntb_async_tx(qp, entry);
1493
1494         qp->tx_index++;
1495         qp->tx_index %= qp->tx_max_entry;
1496
1497         qp->tx_pkts++;
1498
1499         return 0;
1500 }
1501
1502 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1503 {
1504         struct pci_dev *pdev = qp->ndev->pdev;
1505         struct ntb_queue_entry *entry;
1506         int i, rc;
1507
1508         if (!qp->link_is_up)
1509                 return;
1510
1511         dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1512
1513         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1514                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1515                 if (entry)
1516                         break;
1517                 msleep(100);
1518         }
1519
1520         if (!entry)
1521                 return;
1522
1523         entry->cb_data = NULL;
1524         entry->buf = NULL;
1525         entry->len = 0;
1526         entry->flags = LINK_DOWN_FLAG;
1527
1528         rc = ntb_process_tx(qp, entry);
1529         if (rc)
1530                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1531                         qp->qp_num);
1532
1533         ntb_qp_link_down_reset(qp);
1534 }
1535
1536 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1537 {
1538         return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1539 }
1540
1541 /**
1542  * ntb_transport_create_queue - Create a new NTB transport layer queue
1543  * @rx_handler: receive callback function
1544  * @tx_handler: transmit callback function
1545  * @event_handler: event callback function
1546  *
1547  * Create a new NTB transport layer queue and provide the queue with a callback
1548  * routine for both transmit and receive.  The receive callback routine will be
1549  * used to pass up data when the transport has received it on the queue.   The
1550  * transmit callback routine will be called when the transport has completed the
1551  * transmission of the data on the queue and the data is ready to be freed.
1552  *
1553  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1554  */
1555 struct ntb_transport_qp *
1556 ntb_transport_create_queue(void *data, struct device *client_dev,
1557                            const struct ntb_queue_handlers *handlers)
1558 {
1559         struct ntb_dev *ndev;
1560         struct pci_dev *pdev;
1561         struct ntb_transport_ctx *nt;
1562         struct ntb_queue_entry *entry;
1563         struct ntb_transport_qp *qp;
1564         u64 qp_bit;
1565         unsigned int free_queue;
1566         dma_cap_mask_t dma_mask;
1567         int node;
1568         int i;
1569
1570         ndev = dev_ntb(client_dev->parent);
1571         pdev = ndev->pdev;
1572         nt = ndev->ctx;
1573
1574         node = dev_to_node(&ndev->dev);
1575
1576         free_queue = ffs(nt->qp_bitmap);
1577         if (!free_queue)
1578                 goto err;
1579
1580         /* decrement free_queue to make it zero based */
1581         free_queue--;
1582
1583         qp = &nt->qp_vec[free_queue];
1584         qp_bit = BIT_ULL(qp->qp_num);
1585
1586         nt->qp_bitmap_free &= ~qp_bit;
1587
1588         qp->cb_data = data;
1589         qp->rx_handler = handlers->rx_handler;
1590         qp->tx_handler = handlers->tx_handler;
1591         qp->event_handler = handlers->event_handler;
1592
1593         dma_cap_zero(dma_mask);
1594         dma_cap_set(DMA_MEMCPY, dma_mask);
1595
1596         if (use_dma) {
1597                 qp->dma_chan = dma_request_channel(dma_mask, ntb_dma_filter_fn,
1598                                                    (void *)(unsigned long)node);
1599                 if (!qp->dma_chan)
1600                         dev_info(&pdev->dev, "Unable to allocate DMA channel\n");
1601         } else {
1602                 qp->dma_chan = NULL;
1603         }
1604         dev_dbg(&pdev->dev, "Using %s memcpy\n", qp->dma_chan ? "DMA" : "CPU");
1605
1606         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1607                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1608                 if (!entry)
1609                         goto err1;
1610
1611                 entry->qp = qp;
1612                 ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
1613                              &qp->rx_free_q);
1614         }
1615
1616         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1617                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1618                 if (!entry)
1619                         goto err2;
1620
1621                 entry->qp = qp;
1622                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1623                              &qp->tx_free_q);
1624         }
1625
1626         ntb_db_clear(qp->ndev, qp_bit);
1627         ntb_db_clear_mask(qp->ndev, qp_bit);
1628
1629         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1630
1631         return qp;
1632
1633 err2:
1634         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1635                 kfree(entry);
1636 err1:
1637         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1638                 kfree(entry);
1639         if (qp->dma_chan)
1640                 dma_release_channel(qp->dma_chan);
1641         nt->qp_bitmap_free |= qp_bit;
1642 err:
1643         return NULL;
1644 }
1645 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1646
1647 /**
1648  * ntb_transport_free_queue - Frees NTB transport queue
1649  * @qp: NTB queue to be freed
1650  *
1651  * Frees NTB transport queue
1652  */
1653 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1654 {
1655         struct ntb_transport_ctx *nt = qp->transport;
1656         struct pci_dev *pdev;
1657         struct ntb_queue_entry *entry;
1658         u64 qp_bit;
1659
1660         if (!qp)
1661                 return;
1662
1663         pdev = qp->ndev->pdev;
1664
1665         if (qp->dma_chan) {
1666                 struct dma_chan *chan = qp->dma_chan;
1667                 /* Putting the dma_chan to NULL will force any new traffic to be
1668                  * processed by the CPU instead of the DAM engine
1669                  */
1670                 qp->dma_chan = NULL;
1671
1672                 /* Try to be nice and wait for any queued DMA engine
1673                  * transactions to process before smashing it with a rock
1674                  */
1675                 dma_sync_wait(chan, qp->last_cookie);
1676                 dmaengine_terminate_all(chan);
1677                 dma_release_channel(chan);
1678         }
1679
1680         qp_bit = BIT_ULL(qp->qp_num);
1681
1682         ntb_db_set_mask(qp->ndev, qp_bit);
1683         tasklet_disable(&qp->rxc_db_work);
1684
1685         cancel_delayed_work_sync(&qp->link_work);
1686
1687         qp->cb_data = NULL;
1688         qp->rx_handler = NULL;
1689         qp->tx_handler = NULL;
1690         qp->event_handler = NULL;
1691
1692         while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
1693                 kfree(entry);
1694
1695         while ((entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
1696                 dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
1697                 kfree(entry);
1698         }
1699
1700         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1701                 kfree(entry);
1702
1703         nt->qp_bitmap_free |= qp_bit;
1704
1705         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1706 }
1707 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1708
1709 /**
1710  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1711  * @qp: NTB queue to be freed
1712  * @len: pointer to variable to write enqueued buffers length
1713  *
1714  * Dequeues unused buffers from receive queue.  Should only be used during
1715  * shutdown of qp.
1716  *
1717  * RETURNS: NULL error value on error, or void* for success.
1718  */
1719 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1720 {
1721         struct ntb_queue_entry *entry;
1722         void *buf;
1723
1724         if (!qp || qp->client_ready)
1725                 return NULL;
1726
1727         entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
1728         if (!entry)
1729                 return NULL;
1730
1731         buf = entry->cb_data;
1732         *len = entry->len;
1733
1734         ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
1735
1736         return buf;
1737 }
1738 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1739
1740 /**
1741  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1742  * @qp: NTB transport layer queue the entry is to be enqueued on
1743  * @cb: per buffer pointer for callback function to use
1744  * @data: pointer to data buffer that incoming packets will be copied into
1745  * @len: length of the data buffer
1746  *
1747  * Enqueue a new receive buffer onto the transport queue into which a NTB
1748  * payload can be received into.
1749  *
1750  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1751  */
1752 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1753                              unsigned int len)
1754 {
1755         struct ntb_queue_entry *entry;
1756
1757         if (!qp)
1758                 return -EINVAL;
1759
1760         entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
1761         if (!entry)
1762                 return -ENOMEM;
1763
1764         entry->cb_data = cb;
1765         entry->buf = data;
1766         entry->len = len;
1767
1768         ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
1769
1770         return 0;
1771 }
1772 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1773
1774 /**
1775  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1776  * @qp: NTB transport layer queue the entry is to be enqueued on
1777  * @cb: per buffer pointer for callback function to use
1778  * @data: pointer to data buffer that will be sent
1779  * @len: length of the data buffer
1780  *
1781  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1782  * payload will be transmitted.  This assumes that a lock is being held to
1783  * serialize access to the qp.
1784  *
1785  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1786  */
1787 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1788                              unsigned int len)
1789 {
1790         struct ntb_queue_entry *entry;
1791         int rc;
1792
1793         if (!qp || !qp->link_is_up || !len)
1794                 return -EINVAL;
1795
1796         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1797         if (!entry) {
1798                 qp->tx_err_no_buf++;
1799                 return -ENOMEM;
1800         }
1801
1802         entry->cb_data = cb;
1803         entry->buf = data;
1804         entry->len = len;
1805         entry->flags = 0;
1806
1807         rc = ntb_process_tx(qp, entry);
1808         if (rc)
1809                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1810                              &qp->tx_free_q);
1811
1812         return rc;
1813 }
1814 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1815
1816 /**
1817  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1818  * @qp: NTB transport layer queue to be enabled
1819  *
1820  * Notify NTB transport layer of client readiness to use queue
1821  */
1822 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1823 {
1824         if (!qp)
1825                 return;
1826
1827         qp->client_ready = true;
1828
1829         if (qp->transport->link_is_up)
1830                 schedule_delayed_work(&qp->link_work, 0);
1831 }
1832 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
1833
1834 /**
1835  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
1836  * @qp: NTB transport layer queue to be disabled
1837  *
1838  * Notify NTB transport layer of client's desire to no longer receive data on
1839  * transport queue specified.  It is the client's responsibility to ensure all
1840  * entries on queue are purged or otherwise handled appropriately.
1841  */
1842 void ntb_transport_link_down(struct ntb_transport_qp *qp)
1843 {
1844         struct pci_dev *pdev;
1845         int val;
1846
1847         if (!qp)
1848                 return;
1849
1850         pdev = qp->ndev->pdev;
1851         qp->client_ready = false;
1852
1853         val = ntb_spad_read(qp->ndev, QP_LINKS);
1854
1855         ntb_peer_spad_write(qp->ndev, QP_LINKS,
1856                             val & ~BIT(qp->qp_num));
1857
1858         if (qp->link_is_up)
1859                 ntb_send_link_down(qp);
1860         else
1861                 cancel_delayed_work_sync(&qp->link_work);
1862 }
1863 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
1864
1865 /**
1866  * ntb_transport_link_query - Query transport link state
1867  * @qp: NTB transport layer queue to be queried
1868  *
1869  * Query connectivity to the remote system of the NTB transport queue
1870  *
1871  * RETURNS: true for link up or false for link down
1872  */
1873 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
1874 {
1875         if (!qp)
1876                 return false;
1877
1878         return qp->link_is_up;
1879 }
1880 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
1881
1882 /**
1883  * ntb_transport_qp_num - Query the qp number
1884  * @qp: NTB transport layer queue to be queried
1885  *
1886  * Query qp number of the NTB transport queue
1887  *
1888  * RETURNS: a zero based number specifying the qp number
1889  */
1890 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
1891 {
1892         if (!qp)
1893                 return 0;
1894
1895         return qp->qp_num;
1896 }
1897 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
1898
1899 /**
1900  * ntb_transport_max_size - Query the max payload size of a qp
1901  * @qp: NTB transport layer queue to be queried
1902  *
1903  * Query the maximum payload size permissible on the given qp
1904  *
1905  * RETURNS: the max payload size of a qp
1906  */
1907 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
1908 {
1909         unsigned int max;
1910
1911         if (!qp)
1912                 return 0;
1913
1914         if (!qp->dma_chan)
1915                 return qp->tx_max_frame - sizeof(struct ntb_payload_header);
1916
1917         /* If DMA engine usage is possible, try to find the max size for that */
1918         max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
1919         max -= max % (1 << qp->dma_chan->device->copy_align);
1920
1921         return max;
1922 }
1923 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
1924
1925 static void ntb_transport_doorbell_callback(void *data, int vector)
1926 {
1927         struct ntb_transport_ctx *nt = data;
1928         struct ntb_transport_qp *qp;
1929         u64 db_bits;
1930         unsigned int qp_num;
1931
1932         db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
1933                    ntb_db_vector_mask(nt->ndev, vector));
1934
1935         while (db_bits) {
1936                 qp_num = __ffs(db_bits);
1937                 qp = &nt->qp_vec[qp_num];
1938
1939                 tasklet_schedule(&qp->rxc_db_work);
1940
1941                 db_bits &= ~BIT_ULL(qp_num);
1942         }
1943 }
1944
1945 static const struct ntb_ctx_ops ntb_transport_ops = {
1946         .link_event = ntb_transport_event_callback,
1947         .db_event = ntb_transport_doorbell_callback,
1948 };
1949
1950 static struct ntb_client ntb_transport_client = {
1951         .ops = {
1952                 .probe = ntb_transport_probe,
1953                 .remove = ntb_transport_free,
1954         },
1955 };
1956
1957 static int __init ntb_transport_init(void)
1958 {
1959         int rc;
1960
1961         pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
1962
1963         if (debugfs_initialized())
1964                 nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
1965
1966         rc = bus_register(&ntb_transport_bus);
1967         if (rc)
1968                 goto err_bus;
1969
1970         rc = ntb_register_client(&ntb_transport_client);
1971         if (rc)
1972                 goto err_client;
1973
1974         return 0;
1975
1976 err_client:
1977         bus_unregister(&ntb_transport_bus);
1978 err_bus:
1979         debugfs_remove_recursive(nt_debugfs_dir);
1980         return rc;
1981 }
1982 module_init(ntb_transport_init);
1983
1984 static void __exit ntb_transport_exit(void)
1985 {
1986         debugfs_remove_recursive(nt_debugfs_dir);
1987
1988         ntb_unregister_client(&ntb_transport_client);
1989         bus_unregister(&ntb_transport_bus);
1990 }
1991 module_exit(ntb_transport_exit);