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         bool active;
 128
 129         u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
 130         u64 qp_bit;
 131
 132         struct ntb_rx_info __iomem *rx_info;
 133         struct ntb_rx_info *remote_rx_info;
 134
 135         void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 136                            void *data, int len);
 137         struct list_head tx_free_q;
 138         spinlock_t ntb_tx_free_q_lock;
 139         void __iomem *tx_mw;
 140         dma_addr_t tx_mw_phys;
 141         unsigned int tx_index;
 142         unsigned int tx_max_entry;
 143         unsigned int tx_max_frame;
 144
 145         void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 146                            void *data, int len);
 147         struct list_head rx_post_q;
 148         struct list_head rx_pend_q;
 149         struct list_head rx_free_q;
 150         /* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
 151         spinlock_t ntb_rx_q_lock;
 152         void *rx_buff;
 153         unsigned int rx_index;
 154         unsigned int rx_max_entry;
 155         unsigned int rx_max_frame;
 156         unsigned int rx_alloc_entry;
 157         dma_cookie_t last_cookie;
 158         struct tasklet_struct rxc_db_work;
 159
 160         void (*event_handler)(void *data, int status);
 161         struct delayed_work link_work;
 162         struct work_struct link_cleanup;
 163
 164         struct dentry *debugfs_dir;
 165         struct dentry *debugfs_stats;
 166
 167         /* Stats */
 168         u64 rx_bytes;
 169         u64 rx_pkts;
 170         u64 rx_ring_empty;
 171         u64 rx_err_no_buf;
 172         u64 rx_err_oflow;
 173         u64 rx_err_ver;
 174         u64 rx_memcpy;
 175         u64 rx_async;
 176         u64 dma_rx_prep_err;
 177         u64 tx_bytes;
 178         u64 tx_pkts;
 179         u64 tx_ring_full;
 180         u64 tx_err_no_buf;
 181         u64 tx_memcpy;
 182         u64 tx_async;
 183         u64 dma_tx_prep_err;
 184 };
 185
 186 struct ntb_transport_mw {
 187         phys_addr_t phys_addr;
 188         resource_size_t phys_size;
 189         resource_size_t xlat_align;
 190         resource_size_t xlat_align_size;
 191         void __iomem *vbase;
 192         size_t xlat_size;
 193         size_t buff_size;
 194         void *virt_addr;
 195         dma_addr_t dma_addr;
 196 };
 197
 198 struct ntb_transport_client_dev {
 199         struct list_head entry;
 200         struct ntb_transport_ctx *nt;
 201         struct device dev;
 202 };
 203
 204 struct ntb_transport_ctx {
 205         struct list_head entry;
 206         struct list_head client_devs;
 207
 208         struct ntb_dev *ndev;
 209
 210         struct ntb_transport_mw *mw_vec;
 211         struct ntb_transport_qp *qp_vec;
 212         unsigned int mw_count;
 213         unsigned int qp_count;
 214         u64 qp_bitmap;
 215         u64 qp_bitmap_free;
 216
 217         bool link_is_up;
 218         struct delayed_work link_work;
 219         struct work_struct link_cleanup;
 220
 221         struct dentry *debugfs_node_dir;
 222 };
 223
 224 enum {
 225         DESC_DONE_FLAG = BIT(0),
 226         LINK_DOWN_FLAG = BIT(1),
 227 };
 228
 229 struct ntb_payload_header {
 230         unsigned int ver;
 231         unsigned int len;
 232         unsigned int flags;
 233 };
 234
 235 enum {
 236         VERSION = 0,
 237         QP_LINKS,
 238         NUM_QPS,
 239         NUM_MWS,
 240         MW0_SZ_HIGH,
 241         MW0_SZ_LOW,
 242         MW1_SZ_HIGH,
 243         MW1_SZ_LOW,
 244         MAX_SPAD,
 245 };
 246
 247 #define dev_client_dev(__dev) \
 248         container_of((__dev), struct ntb_transport_client_dev, dev)
 249
 250 #define drv_client(__drv) \
 251         container_of((__drv), struct ntb_transport_client, driver)
 252
 253 #define QP_TO_MW(nt, qp)        ((qp) % nt->mw_count)
 254 #define NTB_QP_DEF_NUM_ENTRIES  100
 255 #define NTB_LINK_DOWN_TIMEOUT   10
 256 #define DMA_RETRIES             20
 257 #define DMA_OUT_RESOURCE_TO     50
 258
 259 static void ntb_transport_rxc_db(unsigned long data);
 260 static const struct ntb_ctx_ops ntb_transport_ops;
 261 static struct ntb_client ntb_transport_client;
 262
 263 static int ntb_transport_bus_match(struct device *dev,
 264                                    struct device_driver *drv)
 265 {
 266         return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
 267 }
 268
 269 static int ntb_transport_bus_probe(struct device *dev)
 270 {
 271         const struct ntb_transport_client *client;
 272         int rc = -EINVAL;
 273
 274         get_device(dev);
 275
 276         client = drv_client(dev->driver);
 277         rc = client->probe(dev);
 278         if (rc)
 279                 put_device(dev);
 280
 281         return rc;
 282 }
 283
 284 static int ntb_transport_bus_remove(struct device *dev)
 285 {
 286         const struct ntb_transport_client *client;
 287
 288         client = drv_client(dev->driver);
 289         client->remove(dev);
 290
 291         put_device(dev);
 292
 293         return 0;
 294 }
 295
 296 static struct bus_type ntb_transport_bus = {
 297         .name = "ntb_transport",
 298         .match = ntb_transport_bus_match,
 299         .probe = ntb_transport_bus_probe,
 300         .remove = ntb_transport_bus_remove,
 301 };
 302
 303 static LIST_HEAD(ntb_transport_list);
 304
 305 static int ntb_bus_init(struct ntb_transport_ctx *nt)
 306 {
 307         list_add_tail(&nt->entry, &ntb_transport_list);
 308         return 0;
 309 }
 310
 311 static void ntb_bus_remove(struct ntb_transport_ctx *nt)
 312 {
 313         struct ntb_transport_client_dev *client_dev, *cd;
 314
 315         list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
 316                 dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
 317                         dev_name(&client_dev->dev));
 318                 list_del(&client_dev->entry);
 319                 device_unregister(&client_dev->dev);
 320         }
 321
 322         list_del(&nt->entry);
 323 }
 324
 325 static void ntb_transport_client_release(struct device *dev)
 326 {
 327         struct ntb_transport_client_dev *client_dev;
 328
 329         client_dev = dev_client_dev(dev);
 330         kfree(client_dev);
 331 }
 332
 333 /**
 334  * ntb_transport_unregister_client_dev - Unregister NTB client device
 335  * @device_name: Name of NTB client device
 336  *
 337  * Unregister an NTB client device with the NTB transport layer
 338  */
 339 void ntb_transport_unregister_client_dev(char *device_name)
 340 {
 341         struct ntb_transport_client_dev *client, *cd;
 342         struct ntb_transport_ctx *nt;
 343
 344         list_for_each_entry(nt, &ntb_transport_list, entry)
 345                 list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
 346                         if (!strncmp(dev_name(&client->dev), device_name,
 347                                      strlen(device_name))) {
 348                                 list_del(&client->entry);
 349                                 device_unregister(&client->dev);
 350                         }
 351 }
 352 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
 353
 354 /**
 355  * ntb_transport_register_client_dev - Register NTB client device
 356  * @device_name: Name of NTB client device
 357  *
 358  * Register an NTB client device with the NTB transport layer
 359  */
 360 int ntb_transport_register_client_dev(char *device_name)
 361 {
 362         struct ntb_transport_client_dev *client_dev;
 363         struct ntb_transport_ctx *nt;
 364         int node;
 365         int rc, i = 0;
 366
 367         if (list_empty(&ntb_transport_list))
 368                 return -ENODEV;
 369
 370         list_for_each_entry(nt, &ntb_transport_list, entry) {
 371                 struct device *dev;
 372
 373                 node = dev_to_node(&nt->ndev->dev);
 374
 375                 client_dev = kzalloc_node(sizeof(*client_dev),
 376                                           GFP_KERNEL, node);
 377                 if (!client_dev) {
 378                         rc = -ENOMEM;
 379                         goto err;
 380                 }
 381
 382                 dev = &client_dev->dev;
 383
 384                 /* setup and register client devices */
 385                 dev_set_name(dev, "%s%d", device_name, i);
 386                 dev->bus = &ntb_transport_bus;
 387                 dev->release = ntb_transport_client_release;
 388                 dev->parent = &nt->ndev->dev;
 389
 390                 rc = device_register(dev);
 391                 if (rc) {
 392                         kfree(client_dev);
 393                         goto err;
 394                 }
 395
 396                 list_add_tail(&client_dev->entry, &nt->client_devs);
 397                 i++;
 398         }
 399
 400         return 0;
 401
 402 err:
 403         ntb_transport_unregister_client_dev(device_name);
 404
 405         return rc;
 406 }
 407 EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
 408
 409 /**
 410  * ntb_transport_register_client - Register NTB client driver
 411  * @drv: NTB client driver to be registered
 412  *
 413  * Register an NTB client driver with the NTB transport layer
 414  *
 415  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 416  */
 417 int ntb_transport_register_client(struct ntb_transport_client *drv)
 418 {
 419         drv->driver.bus = &ntb_transport_bus;
 420
 421         if (list_empty(&ntb_transport_list))
 422                 return -ENODEV;
 423
 424         return driver_register(&drv->driver);
 425 }
 426 EXPORT_SYMBOL_GPL(ntb_transport_register_client);
 427
 428 /**
 429  * ntb_transport_unregister_client - Unregister NTB client driver
 430  * @drv: NTB client driver to be unregistered
 431  *
 432  * Unregister an NTB client driver with the NTB transport layer
 433  *
 434  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
 435  */
 436 void ntb_transport_unregister_client(struct ntb_transport_client *drv)
 437 {
 438         driver_unregister(&drv->driver);
 439 }
 440 EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
 441
 442 static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 443                             loff_t *offp)
 444 {
 445         struct ntb_transport_qp *qp;
 446         char *buf;
 447         ssize_t ret, out_offset, out_count;
 448
 449         qp = filp->private_data;
 450
 451         if (!qp || !qp->link_is_up)
 452                 return 0;
 453
 454         out_count = 1000;
 455
 456         buf = kmalloc(out_count, GFP_KERNEL);
 457         if (!buf)
 458                 return -ENOMEM;
 459
 460         out_offset = 0;
 461         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 462                                "\nNTB QP stats:\n\n");
 463         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 464                                "rx_bytes - \t%llu\n", qp->rx_bytes);
 465         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 466                                "rx_pkts - \t%llu\n", qp->rx_pkts);
 467         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 468                                "rx_memcpy - \t%llu\n", qp->rx_memcpy);
 469         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 470                                "rx_async - \t%llu\n", qp->rx_async);
 471         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 472                                "rx_ring_empty - %llu\n", qp->rx_ring_empty);
 473         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 474                                "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
 475         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 476                                "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
 477         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 478                                "rx_err_ver - \t%llu\n", qp->rx_err_ver);
 479         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 480                                "rx_buff - \t0x%p\n", qp->rx_buff);
 481         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 482                                "rx_index - \t%u\n", qp->rx_index);
 483         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 484                                "rx_max_entry - \t%u\n", qp->rx_max_entry);
 485         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 486                                "rx_alloc_entry - \t%u\n\n", qp->rx_alloc_entry);
 487
 488         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 489                                "tx_bytes - \t%llu\n", qp->tx_bytes);
 490         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 491                                "tx_pkts - \t%llu\n", qp->tx_pkts);
 492         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 493                                "tx_memcpy - \t%llu\n", qp->tx_memcpy);
 494         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 495                                "tx_async - \t%llu\n", qp->tx_async);
 496         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 497                                "tx_ring_full - \t%llu\n", qp->tx_ring_full);
 498         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 499                                "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
 500         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 501                                "tx_mw - \t0x%p\n", qp->tx_mw);
 502         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 503                                "tx_index (H) - \t%u\n", qp->tx_index);
 504         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 505                                "RRI (T) - \t%u\n",
 506                                qp->remote_rx_info->entry);
 507         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 508                                "tx_max_entry - \t%u\n", qp->tx_max_entry);
 509         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 510                                "free tx - \t%u\n",
 511                                ntb_transport_tx_free_entry(qp));
 512         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 513                                "DMA tx prep err - \t%llu\n",
 514                                qp->dma_tx_prep_err);
 515         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 516                                "DMA rx prep err - \t%llu\n",
 517                                qp->dma_rx_prep_err);
 518
 519         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 520                                "\n");
 521         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 522                                "Using TX DMA - \t%s\n",
 523                                qp->tx_dma_chan ? "Yes" : "No");
 524         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 525                                "Using RX DMA - \t%s\n",
 526                                qp->rx_dma_chan ? "Yes" : "No");
 527         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 528                                "QP Link - \t%s\n",
 529                                qp->link_is_up ? "Up" : "Down");
 530         out_offset += snprintf(buf + out_offset, out_count - out_offset,
 531                                "\n");
 532
 533         if (out_offset > out_count)
 534                 out_offset = out_count;
 535
 536         ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
 537         kfree(buf);
 538         return ret;
 539 }
 540
 541 static const struct file_operations ntb_qp_debugfs_stats = {
 542         .owner = THIS_MODULE,
 543         .open = simple_open,
 544         .read = debugfs_read,
 545 };
 546
 547 static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
 548                          struct list_head *list)
 549 {
 550         unsigned long flags;
 551
 552         spin_lock_irqsave(lock, flags);
 553         list_add_tail(entry, list);
 554         spin_unlock_irqrestore(lock, flags);
 555 }
 556
 557 static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
 558                                            struct list_head *list)
 559 {
 560         struct ntb_queue_entry *entry;
 561         unsigned long flags;
 562
 563         spin_lock_irqsave(lock, flags);
 564         if (list_empty(list)) {
 565                 entry = NULL;
 566                 goto out;
 567         }
 568         entry = list_first_entry(list, struct ntb_queue_entry, entry);
 569         list_del(&entry->entry);
 570
 571 out:
 572         spin_unlock_irqrestore(lock, flags);
 573
 574         return entry;
 575 }
 576
 577 static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
 578                                            struct list_head *list,
 579                                            struct list_head *to_list)
 580 {
 581         struct ntb_queue_entry *entry;
 582         unsigned long flags;
 583
 584         spin_lock_irqsave(lock, flags);
 585
 586         if (list_empty(list)) {
 587                 entry = NULL;
 588         } else {
 589                 entry = list_first_entry(list, struct ntb_queue_entry, entry);
 590                 list_move_tail(&entry->entry, to_list);
 591         }
 592
 593         spin_unlock_irqrestore(lock, flags);
 594
 595         return entry;
 596 }
 597
 598 static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 599                                      unsigned int qp_num)
 600 {
 601         struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
 602         struct ntb_transport_mw *mw;
 603         struct ntb_dev *ndev = nt->ndev;
 604         struct ntb_queue_entry *entry;
 605         unsigned int rx_size, num_qps_mw;
 606         unsigned int mw_num, mw_count, qp_count;
 607         unsigned int i;
 608         int node;
 609
 610         mw_count = nt->mw_count;
 611         qp_count = nt->qp_count;
 612
 613         mw_num = QP_TO_MW(nt, qp_num);
 614         mw = &nt->mw_vec[mw_num];
 615
 616         if (!mw->virt_addr)
 617                 return -ENOMEM;
 618
 619         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 620                 num_qps_mw = qp_count / mw_count + 1;
 621         else
 622                 num_qps_mw = qp_count / mw_count;
 623
 624         rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
 625         qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
 626         rx_size -= sizeof(struct ntb_rx_info);
 627
 628         qp->remote_rx_info = qp->rx_buff + rx_size;
 629
 630         /* Due to housekeeping, there must be atleast 2 buffs */
 631         qp->rx_max_frame = min(transport_mtu, rx_size / 2);
 632         qp->rx_max_entry = rx_size / qp->rx_max_frame;
 633         qp->rx_index = 0;
 634
 635         /*
 636          * Checking to see if we have more entries than the default.
 637          * We should add additional entries if that is the case so we
 638          * can be in sync with the transport frames.
 639          */
 640         node = dev_to_node(&ndev->dev);
 641         for (i = qp->rx_alloc_entry; i < qp->rx_max_entry; i++) {
 642                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
 643                 if (!entry)
 644                         return -ENOMEM;
 645
 646                 entry->qp = qp;
 647                 ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
 648                              &qp->rx_free_q);
 649                 qp->rx_alloc_entry++;
 650         }
 651
 652         qp->remote_rx_info->entry = qp->rx_max_entry - 1;
 653
 654         /* setup the hdr offsets with 0's */
 655         for (i = 0; i < qp->rx_max_entry; i++) {
 656                 void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
 657                                 sizeof(struct ntb_payload_header));
 658                 memset(offset, 0, sizeof(struct ntb_payload_header));
 659         }
 660
 661         qp->rx_pkts = 0;
 662         qp->tx_pkts = 0;
 663         qp->tx_index = 0;
 664
 665         return 0;
 666 }
 667
 668 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 669 {
 670         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 671         struct pci_dev *pdev = nt->ndev->pdev;
 672
 673         if (!mw->virt_addr)
 674                 return;
 675
 676         ntb_mw_clear_trans(nt->ndev, num_mw);
 677         dma_free_coherent(&pdev->dev, mw->buff_size,
 678                           mw->virt_addr, mw->dma_addr);
 679         mw->xlat_size = 0;
 680         mw->buff_size = 0;
 681         mw->virt_addr = NULL;
 682 }
 683
 684 static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 685                       resource_size_t size)
 686 {
 687         struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
 688         struct pci_dev *pdev = nt->ndev->pdev;
 689         size_t xlat_size, buff_size;
 690         int rc;
 691
 692         if (!size)
 693                 return -EINVAL;
 694
 695         xlat_size = round_up(size, mw->xlat_align_size);
 696         buff_size = round_up(size, mw->xlat_align);
 697
 698         /* No need to re-setup */
 699         if (mw->xlat_size == xlat_size)
 700                 return 0;
 701
 702         if (mw->buff_size)
 703                 ntb_free_mw(nt, num_mw);
 704
 705         /* Alloc memory for receiving data.  Must be aligned */
 706         mw->xlat_size = xlat_size;
 707         mw->buff_size = buff_size;
 708
 709         mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_size,
 710                                            &mw->dma_addr, GFP_KERNEL);
 711         if (!mw->virt_addr) {
 712                 mw->xlat_size = 0;
 713                 mw->buff_size = 0;
 714                 dev_err(&pdev->dev, "Unable to alloc MW buff of size %zu\n",
 715                         buff_size);
 716                 return -ENOMEM;
 717         }
 718
 719         /*
 720          * we must ensure that the memory address allocated is BAR size
 721          * aligned in order for the XLAT register to take the value. This
 722          * is a requirement of the hardware. It is recommended to setup CMA
 723          * for BAR sizes equal or greater than 4MB.
 724          */
 725         if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
 726                 dev_err(&pdev->dev, "DMA memory %pad is not aligned\n",
 727                         &mw->dma_addr);
 728                 ntb_free_mw(nt, num_mw);
 729                 return -ENOMEM;
 730         }
 731
 732         /* Notify HW the memory location of the receive buffer */
 733         rc = ntb_mw_set_trans(nt->ndev, num_mw, mw->dma_addr, mw->xlat_size);
 734         if (rc) {
 735                 dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
 736                 ntb_free_mw(nt, num_mw);
 737                 return -EIO;
 738         }
 739
 740         return 0;
 741 }
 742
 743 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 744 {
 745         qp->link_is_up = false;
 746         qp->active = false;
 747
 748         qp->tx_index = 0;
 749         qp->rx_index = 0;
 750         qp->rx_bytes = 0;
 751         qp->rx_pkts = 0;
 752         qp->rx_ring_empty = 0;
 753         qp->rx_err_no_buf = 0;
 754         qp->rx_err_oflow = 0;
 755         qp->rx_err_ver = 0;
 756         qp->rx_memcpy = 0;
 757         qp->rx_async = 0;
 758         qp->tx_bytes = 0;
 759         qp->tx_pkts = 0;
 760         qp->tx_ring_full = 0;
 761         qp->tx_err_no_buf = 0;
 762         qp->tx_memcpy = 0;
 763         qp->tx_async = 0;
 764         qp->dma_tx_prep_err = 0;
 765         qp->dma_rx_prep_err = 0;
 766 }
 767
 768 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
 769 {
 770         struct ntb_transport_ctx *nt = qp->transport;
 771         struct pci_dev *pdev = nt->ndev->pdev;
 772
 773         dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
 774
 775         cancel_delayed_work_sync(&qp->link_work);
 776         ntb_qp_link_down_reset(qp);
 777
 778         if (qp->event_handler)
 779                 qp->event_handler(qp->cb_data, qp->link_is_up);
 780 }
 781
 782 static void ntb_qp_link_cleanup_work(struct work_struct *work)
 783 {
 784         struct ntb_transport_qp *qp = container_of(work,
 785                                                    struct ntb_transport_qp,
 786                                                    link_cleanup);
 787         struct ntb_transport_ctx *nt = qp->transport;
 788
 789         ntb_qp_link_cleanup(qp);
 790
 791         if (nt->link_is_up)
 792                 schedule_delayed_work(&qp->link_work,
 793                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 794 }
 795
 796 static void ntb_qp_link_down(struct ntb_transport_qp *qp)
 797 {
 798         schedule_work(&qp->link_cleanup);
 799 }
 800
 801 static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 802 {
 803         struct ntb_transport_qp *qp;
 804         u64 qp_bitmap_alloc;
 805         int i;
 806
 807         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
 808
 809         /* Pass along the info to any clients */
 810         for (i = 0; i < nt->qp_count; i++)
 811                 if (qp_bitmap_alloc & BIT_ULL(i)) {
 812                         qp = &nt->qp_vec[i];
 813                         ntb_qp_link_cleanup(qp);
 814                         cancel_work_sync(&qp->link_cleanup);
 815                         cancel_delayed_work_sync(&qp->link_work);
 816                 }
 817
 818         if (!nt->link_is_up)
 819                 cancel_delayed_work_sync(&nt->link_work);
 820
 821         /* The scratchpad registers keep the values if the remote side
 822          * goes down, blast them now to give them a sane value the next
 823          * time they are accessed
 824          */
 825         for (i = 0; i < MAX_SPAD; i++)
 826                 ntb_spad_write(nt->ndev, i, 0);
 827 }
 828
 829 static void ntb_transport_link_cleanup_work(struct work_struct *work)
 830 {
 831         struct ntb_transport_ctx *nt =
 832                 container_of(work, struct ntb_transport_ctx, link_cleanup);
 833
 834         ntb_transport_link_cleanup(nt);
 835 }
 836
 837 static void ntb_transport_event_callback(void *data)
 838 {
 839         struct ntb_transport_ctx *nt = data;
 840
 841         if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
 842                 schedule_delayed_work(&nt->link_work, 0);
 843         else
 844                 schedule_work(&nt->link_cleanup);
 845 }
 846
 847 static void ntb_transport_link_work(struct work_struct *work)
 848 {
 849         struct ntb_transport_ctx *nt =
 850                 container_of(work, struct ntb_transport_ctx, link_work.work);
 851         struct ntb_dev *ndev = nt->ndev;
 852         struct pci_dev *pdev = ndev->pdev;
 853         resource_size_t size;
 854         u32 val;
 855         int rc = 0, i, spad;
 856
 857         /* send the local info, in the opposite order of the way we read it */
 858         for (i = 0; i < nt->mw_count; i++) {
 859                 size = nt->mw_vec[i].phys_size;
 860
 861                 if (max_mw_size && size > max_mw_size)
 862                         size = max_mw_size;
 863
 864                 spad = MW0_SZ_HIGH + (i * 2);
 865                 ntb_peer_spad_write(ndev, spad, upper_32_bits(size));
 866
 867                 spad = MW0_SZ_LOW + (i * 2);
 868                 ntb_peer_spad_write(ndev, spad, lower_32_bits(size));
 869         }
 870
 871         ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
 872
 873         ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
 874
 875         ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
 876
 877         /* Query the remote side for its info */
 878         val = ntb_spad_read(ndev, VERSION);
 879         dev_dbg(&pdev->dev, "Remote version = %d\n", val);
 880         if (val != NTB_TRANSPORT_VERSION)
 881                 goto out;
 882
 883         val = ntb_spad_read(ndev, NUM_QPS);
 884         dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
 885         if (val != nt->qp_count)
 886                 goto out;
 887
 888         val = ntb_spad_read(ndev, NUM_MWS);
 889         dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
 890         if (val != nt->mw_count)
 891                 goto out;
 892
 893         for (i = 0; i < nt->mw_count; i++) {
 894                 u64 val64;
 895
 896                 val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
 897                 val64 = (u64)val << 32;
 898
 899                 val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
 900                 val64 |= val;
 901
 902                 dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
 903
 904                 rc = ntb_set_mw(nt, i, val64);
 905                 if (rc)
 906                         goto out1;
 907         }
 908
 909         nt->link_is_up = true;
 910
 911         for (i = 0; i < nt->qp_count; i++) {
 912                 struct ntb_transport_qp *qp = &nt->qp_vec[i];
 913
 914                 ntb_transport_setup_qp_mw(nt, i);
 915
 916                 if (qp->client_ready)
 917                         schedule_delayed_work(&qp->link_work, 0);
 918         }
 919
 920         return;
 921
 922 out1:
 923         for (i = 0; i < nt->mw_count; i++)
 924                 ntb_free_mw(nt, i);
 925
 926         /* if there's an actual failure, we should just bail */
 927         if (rc < 0) {
 928                 ntb_link_disable(ndev);
 929                 return;
 930         }
 931
 932 out:
 933         if (ntb_link_is_up(ndev, NULL, NULL) == 1)
 934                 schedule_delayed_work(&nt->link_work,
 935                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 936 }
 937
 938 static void ntb_qp_link_work(struct work_struct *work)
 939 {
 940         struct ntb_transport_qp *qp = container_of(work,
 941                                                    struct ntb_transport_qp,
 942                                                    link_work.work);
 943         struct pci_dev *pdev = qp->ndev->pdev;
 944         struct ntb_transport_ctx *nt = qp->transport;
 945         int val;
 946
 947         WARN_ON(!nt->link_is_up);
 948
 949         val = ntb_spad_read(nt->ndev, QP_LINKS);
 950
 951         ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
 952
 953         /* query remote spad for qp ready bits */
 954         ntb_peer_spad_read(nt->ndev, QP_LINKS);
 955         dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
 956
 957         /* See if the remote side is up */
 958         if (val & BIT(qp->qp_num)) {
 959                 dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
 960                 qp->link_is_up = true;
 961                 qp->active = true;
 962
 963                 if (qp->event_handler)
 964                         qp->event_handler(qp->cb_data, qp->link_is_up);
 965
 966                 if (qp->active)
 967                         tasklet_schedule(&qp->rxc_db_work);
 968         } else if (nt->link_is_up)
 969                 schedule_delayed_work(&qp->link_work,
 970                                       msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 971 }
 972
 973 static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 974                                     unsigned int qp_num)
 975 {
 976         struct ntb_transport_qp *qp;
 977         phys_addr_t mw_base;
 978         resource_size_t mw_size;
 979         unsigned int num_qps_mw, tx_size;
 980         unsigned int mw_num, mw_count, qp_count;
 981         u64 qp_offset;
 982
 983         mw_count = nt->mw_count;
 984         qp_count = nt->qp_count;
 985
 986         mw_num = QP_TO_MW(nt, qp_num);
 987
 988         qp = &nt->qp_vec[qp_num];
 989         qp->qp_num = qp_num;
 990         qp->transport = nt;
 991         qp->ndev = nt->ndev;
 992         qp->client_ready = false;
 993         qp->event_handler = NULL;
 994         ntb_qp_link_down_reset(qp);
 995
 996         if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
 997                 num_qps_mw = qp_count / mw_count + 1;
 998         else
 999                 num_qps_mw = qp_count / mw_count;
1000
1001         mw_base = nt->mw_vec[mw_num].phys_addr;
1002         mw_size = nt->mw_vec[mw_num].phys_size;
1003
1004         tx_size = (unsigned int)mw_size / num_qps_mw;
1005         qp_offset = tx_size * (qp_num / mw_count);
1006
1007         qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
1008         if (!qp->tx_mw)
1009                 return -EINVAL;
1010
1011         qp->tx_mw_phys = mw_base + qp_offset;
1012         if (!qp->tx_mw_phys)
1013                 return -EINVAL;
1014
1015         tx_size -= sizeof(struct ntb_rx_info);
1016         qp->rx_info = qp->tx_mw + tx_size;
1017
1018         /* Due to housekeeping, there must be atleast 2 buffs */
1019         qp->tx_max_frame = min(transport_mtu, tx_size / 2);
1020         qp->tx_max_entry = tx_size / qp->tx_max_frame;
1021
1022         if (nt->debugfs_node_dir) {
1023                 char debugfs_name[4];
1024
1025                 snprintf(debugfs_name, 4, "qp%d", qp_num);
1026                 qp->debugfs_dir = debugfs_create_dir(debugfs_name,
1027                                                      nt->debugfs_node_dir);
1028
1029                 qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
1030                                                         qp->debugfs_dir, qp,
1031                                                         &ntb_qp_debugfs_stats);
1032         } else {
1033                 qp->debugfs_dir = NULL;
1034                 qp->debugfs_stats = NULL;
1035         }
1036
1037         INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
1038         INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
1039
1040         spin_lock_init(&qp->ntb_rx_q_lock);
1041         spin_lock_init(&qp->ntb_tx_free_q_lock);
1042
1043         INIT_LIST_HEAD(&qp->rx_post_q);
1044         INIT_LIST_HEAD(&qp->rx_pend_q);
1045         INIT_LIST_HEAD(&qp->rx_free_q);
1046         INIT_LIST_HEAD(&qp->tx_free_q);
1047
1048         tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
1049                      (unsigned long)qp);
1050
1051         return 0;
1052 }
1053
1054 static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
1055 {
1056         struct ntb_transport_ctx *nt;
1057         struct ntb_transport_mw *mw;
1058         unsigned int mw_count, qp_count;
1059         u64 qp_bitmap;
1060         int node;
1061         int rc, i;
1062
1063         mw_count = ntb_mw_count(ndev);
1064         if (ntb_spad_count(ndev) < (NUM_MWS + 1 + mw_count * 2)) {
1065                 dev_err(&ndev->dev, "Not enough scratch pad registers for %s",
1066                         NTB_TRANSPORT_NAME);
1067                 return -EIO;
1068         }
1069
1070         if (ntb_db_is_unsafe(ndev))
1071                 dev_dbg(&ndev->dev,
1072                         "doorbell is unsafe, proceed anyway...\n");
1073         if (ntb_spad_is_unsafe(ndev))
1074                 dev_dbg(&ndev->dev,
1075                         "scratchpad is unsafe, proceed anyway...\n");
1076
1077         node = dev_to_node(&ndev->dev);
1078
1079         nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
1080         if (!nt)
1081                 return -ENOMEM;
1082
1083         nt->ndev = ndev;
1084
1085         nt->mw_count = mw_count;
1086
1087         nt->mw_vec = kzalloc_node(mw_count * sizeof(*nt->mw_vec),
1088                                   GFP_KERNEL, node);
1089         if (!nt->mw_vec) {
1090                 rc = -ENOMEM;
1091                 goto err;
1092         }
1093
1094         for (i = 0; i < mw_count; i++) {
1095                 mw = &nt->mw_vec[i];
1096
1097                 rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
1098                                       &mw->xlat_align, &mw->xlat_align_size);
1099                 if (rc)
1100                         goto err1;
1101
1102                 mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
1103                 if (!mw->vbase) {
1104                         rc = -ENOMEM;
1105                         goto err1;
1106                 }
1107
1108                 mw->buff_size = 0;
1109                 mw->xlat_size = 0;
1110                 mw->virt_addr = NULL;
1111                 mw->dma_addr = 0;
1112         }
1113
1114         qp_bitmap = ntb_db_valid_mask(ndev);
1115
1116         qp_count = ilog2(qp_bitmap);
1117         if (max_num_clients && max_num_clients < qp_count)
1118                 qp_count = max_num_clients;
1119         else if (mw_count < qp_count)
1120                 qp_count = mw_count;
1121
1122         qp_bitmap &= BIT_ULL(qp_count) - 1;
1123
1124         nt->qp_count = qp_count;
1125         nt->qp_bitmap = qp_bitmap;
1126         nt->qp_bitmap_free = qp_bitmap;
1127
1128         nt->qp_vec = kzalloc_node(qp_count * sizeof(*nt->qp_vec),
1129                                   GFP_KERNEL, node);
1130         if (!nt->qp_vec) {
1131                 rc = -ENOMEM;
1132                 goto err1;
1133         }
1134
1135         if (nt_debugfs_dir) {
1136                 nt->debugfs_node_dir =
1137                         debugfs_create_dir(pci_name(ndev->pdev),
1138                                            nt_debugfs_dir);
1139         }
1140
1141         for (i = 0; i < qp_count; i++) {
1142                 rc = ntb_transport_init_queue(nt, i);
1143                 if (rc)
1144                         goto err2;
1145         }
1146
1147         INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
1148         INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
1149
1150         rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
1151         if (rc)
1152                 goto err2;
1153
1154         INIT_LIST_HEAD(&nt->client_devs);
1155         rc = ntb_bus_init(nt);
1156         if (rc)
1157                 goto err3;
1158
1159         nt->link_is_up = false;
1160         ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
1161         ntb_link_event(ndev);
1162
1163         return 0;
1164
1165 err3:
1166         ntb_clear_ctx(ndev);
1167 err2:
1168         kfree(nt->qp_vec);
1169 err1:
1170         while (i--) {
1171                 mw = &nt->mw_vec[i];
1172                 iounmap(mw->vbase);
1173         }
1174         kfree(nt->mw_vec);
1175 err:
1176         kfree(nt);
1177         return rc;
1178 }
1179
1180 static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
1181 {
1182         struct ntb_transport_ctx *nt = ndev->ctx;
1183         struct ntb_transport_qp *qp;
1184         u64 qp_bitmap_alloc;
1185         int i;
1186
1187         ntb_transport_link_cleanup(nt);
1188         cancel_work_sync(&nt->link_cleanup);
1189         cancel_delayed_work_sync(&nt->link_work);
1190
1191         qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
1192
1193         /* verify that all the qp's are freed */
1194         for (i = 0; i < nt->qp_count; i++) {
1195                 qp = &nt->qp_vec[i];
1196                 if (qp_bitmap_alloc & BIT_ULL(i))
1197                         ntb_transport_free_queue(qp);
1198                 debugfs_remove_recursive(qp->debugfs_dir);
1199         }
1200
1201         ntb_link_disable(ndev);
1202         ntb_clear_ctx(ndev);
1203
1204         ntb_bus_remove(nt);
1205
1206         for (i = nt->mw_count; i--; ) {
1207                 ntb_free_mw(nt, i);
1208                 iounmap(nt->mw_vec[i].vbase);
1209         }
1210
1211         kfree(nt->qp_vec);
1212         kfree(nt->mw_vec);
1213         kfree(nt);
1214 }
1215
1216 static void ntb_complete_rxc(struct ntb_transport_qp *qp)
1217 {
1218         struct ntb_queue_entry *entry;
1219         void *cb_data;
1220         unsigned int len;
1221         unsigned long irqflags;
1222
1223         spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1224
1225         while (!list_empty(&qp->rx_post_q)) {
1226                 entry = list_first_entry(&qp->rx_post_q,
1227                                          struct ntb_queue_entry, entry);
1228                 if (!(entry->flags & DESC_DONE_FLAG))
1229                         break;
1230
1231                 entry->rx_hdr->flags = 0;
1232                 iowrite32(entry->index, &qp->rx_info->entry);
1233
1234                 cb_data = entry->cb_data;
1235                 len = entry->len;
1236
1237                 list_move_tail(&entry->entry, &qp->rx_free_q);
1238
1239                 spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1240
1241                 if (qp->rx_handler && qp->client_ready)
1242                         qp->rx_handler(qp, qp->cb_data, cb_data, len);
1243
1244                 spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
1245         }
1246
1247         spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
1248 }
1249
1250 static void ntb_rx_copy_callback(void *data)
1251 {
1252         struct ntb_queue_entry *entry = data;
1253
1254         entry->flags |= DESC_DONE_FLAG;
1255
1256         ntb_complete_rxc(entry->qp);
1257 }
1258
1259 static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
1260 {
1261         void *buf = entry->buf;
1262         size_t len = entry->len;
1263
1264         memcpy(buf, offset, len);
1265
1266         /* Ensure that the data is fully copied out before clearing the flag */
1267         wmb();
1268
1269         ntb_rx_copy_callback(entry);
1270 }
1271
1272 static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
1273 {
1274         struct dma_async_tx_descriptor *txd;
1275         struct ntb_transport_qp *qp = entry->qp;
1276         struct dma_chan *chan = qp->rx_dma_chan;
1277         struct dma_device *device;
1278         size_t pay_off, buff_off, len;
1279         struct dmaengine_unmap_data *unmap;
1280         dma_cookie_t cookie;
1281         void *buf = entry->buf;
1282         int retries = 0;
1283
1284         len = entry->len;
1285
1286         if (!chan)
1287                 goto err;
1288
1289         if (len < copy_bytes)
1290                 goto err;
1291
1292         device = chan->device;
1293         pay_off = (size_t)offset & ~PAGE_MASK;
1294         buff_off = (size_t)buf & ~PAGE_MASK;
1295
1296         if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
1297                 goto err;
1298
1299         unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
1300         if (!unmap)
1301                 goto err;
1302
1303         unmap->len = len;
1304         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
1305                                       pay_off, len, DMA_TO_DEVICE);
1306         if (dma_mapping_error(device->dev, unmap->addr[0]))
1307                 goto err_get_unmap;
1308
1309         unmap->to_cnt = 1;
1310
1311         unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
1312                                       buff_off, len, DMA_FROM_DEVICE);
1313         if (dma_mapping_error(device->dev, unmap->addr[1]))
1314                 goto err_get_unmap;
1315
1316         unmap->from_cnt = 1;
1317
1318         for (retries = 0; retries < DMA_RETRIES; retries++) {
1319                 txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
1320                                                      unmap->addr[0], len,
1321                                                      DMA_PREP_INTERRUPT);
1322                 if (txd)
1323                         break;
1324
1325                 set_current_state(TASK_INTERRUPTIBLE);
1326                 schedule_timeout(DMA_OUT_RESOURCE_TO);
1327         }
1328
1329         if (!txd) {
1330                 qp->dma_rx_prep_err++;
1331                 goto err_get_unmap;
1332         }
1333
1334         txd->callback = ntb_rx_copy_callback;
1335         txd->callback_param = entry;
1336         dma_set_unmap(txd, unmap);
1337
1338         cookie = dmaengine_submit(txd);
1339         if (dma_submit_error(cookie))
1340                 goto err_set_unmap;
1341
1342         dmaengine_unmap_put(unmap);
1343
1344         qp->last_cookie = cookie;
1345
1346         qp->rx_async++;
1347
1348         return;
1349
1350 err_set_unmap:
1351         dmaengine_unmap_put(unmap);
1352 err_get_unmap:
1353         dmaengine_unmap_put(unmap);
1354 err:
1355         ntb_memcpy_rx(entry, offset);
1356         qp->rx_memcpy++;
1357 }
1358
1359 static int ntb_process_rxc(struct ntb_transport_qp *qp)
1360 {
1361         struct ntb_payload_header *hdr;
1362         struct ntb_queue_entry *entry;
1363         void *offset;
1364
1365         offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
1366         hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
1367
1368         dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
1369                 qp->qp_num, hdr->ver, hdr->len, hdr->flags);
1370
1371         if (!(hdr->flags & DESC_DONE_FLAG)) {
1372                 dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
1373                 qp->rx_ring_empty++;
1374                 return -EAGAIN;
1375         }
1376
1377         if (hdr->flags & LINK_DOWN_FLAG) {
1378                 dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
1379                 ntb_qp_link_down(qp);
1380                 hdr->flags = 0;
1381                 return -EAGAIN;
1382         }
1383
1384         if (hdr->ver != (u32)qp->rx_pkts) {
1385                 dev_dbg(&qp->ndev->pdev->dev,
1386                         "version mismatch, expected %llu - got %u\n",
1387                         qp->rx_pkts, hdr->ver);
1388                 qp->rx_err_ver++;
1389                 return -EIO;
1390         }
1391
1392         entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
1393         if (!entry) {
1394                 dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
1395                 qp->rx_err_no_buf++;
1396                 return -EAGAIN;
1397         }
1398
1399         entry->rx_hdr = hdr;
1400         entry->index = qp->rx_index;
1401
1402         if (hdr->len > entry->len) {
1403                 dev_dbg(&qp->ndev->pdev->dev,
1404                         "receive buffer overflow! Wanted %d got %d\n",
1405                         hdr->len, entry->len);
1406                 qp->rx_err_oflow++;
1407
1408                 entry->len = -EIO;
1409                 entry->flags |= DESC_DONE_FLAG;
1410
1411                 ntb_complete_rxc(qp);
1412         } else {
1413                 dev_dbg(&qp->ndev->pdev->dev,
1414                         "RX OK index %u ver %u size %d into buf size %d\n",
1415                         qp->rx_index, hdr->ver, hdr->len, entry->len);
1416
1417                 qp->rx_bytes += hdr->len;
1418                 qp->rx_pkts++;
1419
1420                 entry->len = hdr->len;
1421
1422                 ntb_async_rx(entry, offset);
1423         }
1424
1425         qp->rx_index++;
1426         qp->rx_index %= qp->rx_max_entry;
1427
1428         return 0;
1429 }
1430
1431 static void ntb_transport_rxc_db(unsigned long data)
1432 {
1433         struct ntb_transport_qp *qp = (void *)data;
1434         int rc, i;
1435
1436         dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
1437                 __func__, qp->qp_num);
1438
1439         /* Limit the number of packets processed in a single interrupt to
1440          * provide fairness to others
1441          */
1442         for (i = 0; i < qp->rx_max_entry; i++) {
1443                 rc = ntb_process_rxc(qp);
1444                 if (rc)
1445                         break;
1446         }
1447
1448         if (i && qp->rx_dma_chan)
1449                 dma_async_issue_pending(qp->rx_dma_chan);
1450
1451         if (i == qp->rx_max_entry) {
1452                 /* there is more work to do */
1453                 if (qp->active)
1454                         tasklet_schedule(&qp->rxc_db_work);
1455         } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
1456                 /* the doorbell bit is set: clear it */
1457                 ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
1458                 /* ntb_db_read ensures ntb_db_clear write is committed */
1459                 ntb_db_read(qp->ndev);
1460
1461                 /* an interrupt may have arrived between finishing
1462                  * ntb_process_rxc and clearing the doorbell bit:
1463                  * there might be some more work to do.
1464                  */
1465                 if (qp->active)
1466                         tasklet_schedule(&qp->rxc_db_work);
1467         }
1468 }
1469
1470 static void ntb_tx_copy_callback(void *data)
1471 {
1472         struct ntb_queue_entry *entry = data;
1473         struct ntb_transport_qp *qp = entry->qp;
1474         struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
1475
1476         iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
1477
1478         ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
1479
1480         /* The entry length can only be zero if the packet is intended to be a
1481          * "link down" or similar.  Since no payload is being sent in these
1482          * cases, there is nothing to add to the completion queue.
1483          */
1484         if (entry->len > 0) {
1485                 qp->tx_bytes += entry->len;
1486
1487                 if (qp->tx_handler)
1488                         qp->tx_handler(qp, qp->cb_data, entry->cb_data,
1489                                        entry->len);
1490         }
1491
1492         ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
1493 }
1494
1495 static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
1496 {
1497 #ifdef ARCH_HAS_NOCACHE_UACCESS
1498         /*
1499          * Using non-temporal mov to improve performance on non-cached
1500          * writes, even though we aren't actually copying from user space.
1501          */
1502         __copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
1503 #else
1504         memcpy_toio(offset, entry->buf, entry->len);
1505 #endif
1506
1507         /* Ensure that the data is fully copied out before setting the flags */
1508         wmb();
1509
1510         ntb_tx_copy_callback(entry);
1511 }
1512
1513 static void ntb_async_tx(struct ntb_transport_qp *qp,
1514                          struct ntb_queue_entry *entry)
1515 {
1516         struct ntb_payload_header __iomem *hdr;
1517         struct dma_async_tx_descriptor *txd;
1518         struct dma_chan *chan = qp->tx_dma_chan;
1519         struct dma_device *device;
1520         size_t dest_off, buff_off;
1521         struct dmaengine_unmap_data *unmap;
1522         dma_addr_t dest;
1523         dma_cookie_t cookie;
1524         void __iomem *offset;
1525         size_t len = entry->len;
1526         void *buf = entry->buf;
1527         int retries = 0;
1528
1529         offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
1530         hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
1531         entry->tx_hdr = hdr;
1532
1533         iowrite32(entry->len, &hdr->len);
1534         iowrite32((u32)qp->tx_pkts, &hdr->ver);
1535
1536         if (!chan)
1537                 goto err;
1538
1539         if (len < copy_bytes)
1540                 goto err;
1541
1542         device = chan->device;
1543         dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index;
1544         buff_off = (size_t)buf & ~PAGE_MASK;
1545         dest_off = (size_t)dest & ~PAGE_MASK;
1546
1547         if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
1548                 goto err;
1549
1550         unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
1551         if (!unmap)
1552                 goto err;
1553
1554         unmap->len = len;
1555         unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
1556                                       buff_off, len, DMA_TO_DEVICE);
1557         if (dma_mapping_error(device->dev, unmap->addr[0]))
1558                 goto err_get_unmap;
1559
1560         unmap->to_cnt = 1;
1561
1562         for (retries = 0; retries < DMA_RETRIES; retries++) {
1563                 txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0],
1564                                                      len, DMA_PREP_INTERRUPT);
1565                 if (txd)
1566                         break;
1567
1568                 set_current_state(TASK_INTERRUPTIBLE);
1569                 schedule_timeout(DMA_OUT_RESOURCE_TO);
1570         }
1571
1572         if (!txd) {
1573                 qp->dma_tx_prep_err++;
1574                 goto err_get_unmap;
1575         }
1576
1577         txd->callback = ntb_tx_copy_callback;
1578         txd->callback_param = entry;
1579         dma_set_unmap(txd, unmap);
1580
1581         cookie = dmaengine_submit(txd);
1582         if (dma_submit_error(cookie))
1583                 goto err_set_unmap;
1584
1585         dmaengine_unmap_put(unmap);
1586
1587         dma_async_issue_pending(chan);
1588         qp->tx_async++;
1589
1590         return;
1591 err_set_unmap:
1592         dmaengine_unmap_put(unmap);
1593 err_get_unmap:
1594         dmaengine_unmap_put(unmap);
1595 err:
1596         ntb_memcpy_tx(entry, offset);
1597         qp->tx_memcpy++;
1598 }
1599
1600 static int ntb_process_tx(struct ntb_transport_qp *qp,
1601                           struct ntb_queue_entry *entry)
1602 {
1603         if (qp->tx_index == qp->remote_rx_info->entry) {
1604                 qp->tx_ring_full++;
1605                 return -EAGAIN;
1606         }
1607
1608         if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
1609                 if (qp->tx_handler)
1610                         qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
1611
1612                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1613                              &qp->tx_free_q);
1614                 return 0;
1615         }
1616
1617         ntb_async_tx(qp, entry);
1618
1619         qp->tx_index++;
1620         qp->tx_index %= qp->tx_max_entry;
1621
1622         qp->tx_pkts++;
1623
1624         return 0;
1625 }
1626
1627 static void ntb_send_link_down(struct ntb_transport_qp *qp)
1628 {
1629         struct pci_dev *pdev = qp->ndev->pdev;
1630         struct ntb_queue_entry *entry;
1631         int i, rc;
1632
1633         if (!qp->link_is_up)
1634                 return;
1635
1636         dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
1637
1638         for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
1639                 entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1640                 if (entry)
1641                         break;
1642                 msleep(100);
1643         }
1644
1645         if (!entry)
1646                 return;
1647
1648         entry->cb_data = NULL;
1649         entry->buf = NULL;
1650         entry->len = 0;
1651         entry->flags = LINK_DOWN_FLAG;
1652
1653         rc = ntb_process_tx(qp, entry);
1654         if (rc)
1655                 dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
1656                         qp->qp_num);
1657
1658         ntb_qp_link_down_reset(qp);
1659 }
1660
1661 static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
1662 {
1663         return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
1664 }
1665
1666 /**
1667  * ntb_transport_create_queue - Create a new NTB transport layer queue
1668  * @rx_handler: receive callback function
1669  * @tx_handler: transmit callback function
1670  * @event_handler: event callback function
1671  *
1672  * Create a new NTB transport layer queue and provide the queue with a callback
1673  * routine for both transmit and receive.  The receive callback routine will be
1674  * used to pass up data when the transport has received it on the queue.   The
1675  * transmit callback routine will be called when the transport has completed the
1676  * transmission of the data on the queue and the data is ready to be freed.
1677  *
1678  * RETURNS: pointer to newly created ntb_queue, NULL on error.
1679  */
1680 struct ntb_transport_qp *
1681 ntb_transport_create_queue(void *data, struct device *client_dev,
1682                            const struct ntb_queue_handlers *handlers)
1683 {
1684         struct ntb_dev *ndev;
1685         struct pci_dev *pdev;
1686         struct ntb_transport_ctx *nt;
1687         struct ntb_queue_entry *entry;
1688         struct ntb_transport_qp *qp;
1689         u64 qp_bit;
1690         unsigned int free_queue;
1691         dma_cap_mask_t dma_mask;
1692         int node;
1693         int i;
1694
1695         ndev = dev_ntb(client_dev->parent);
1696         pdev = ndev->pdev;
1697         nt = ndev->ctx;
1698
1699         node = dev_to_node(&ndev->dev);
1700
1701         free_queue = ffs(nt->qp_bitmap);
1702         if (!free_queue)
1703                 goto err;
1704
1705         /* decrement free_queue to make it zero based */
1706         free_queue--;
1707
1708         qp = &nt->qp_vec[free_queue];
1709         qp_bit = BIT_ULL(qp->qp_num);
1710
1711         nt->qp_bitmap_free &= ~qp_bit;
1712
1713         qp->cb_data = data;
1714         qp->rx_handler = handlers->rx_handler;
1715         qp->tx_handler = handlers->tx_handler;
1716         qp->event_handler = handlers->event_handler;
1717
1718         dma_cap_zero(dma_mask);
1719         dma_cap_set(DMA_MEMCPY, dma_mask);
1720
1721         if (use_dma) {
1722                 qp->tx_dma_chan =
1723                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1724                                             (void *)(unsigned long)node);
1725                 if (!qp->tx_dma_chan)
1726                         dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
1727
1728                 qp->rx_dma_chan =
1729                         dma_request_channel(dma_mask, ntb_dma_filter_fn,
1730                                             (void *)(unsigned long)node);
1731                 if (!qp->rx_dma_chan)
1732                         dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
1733         } else {
1734                 qp->tx_dma_chan = NULL;
1735                 qp->rx_dma_chan = NULL;
1736         }
1737
1738         dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
1739                 qp->tx_dma_chan ? "DMA" : "CPU");
1740
1741         dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
1742                 qp->rx_dma_chan ? "DMA" : "CPU");
1743
1744         for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
1745                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1746                 if (!entry)
1747                         goto err1;
1748
1749                 entry->qp = qp;
1750                 ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
1751                              &qp->rx_free_q);
1752         }
1753         qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;
1754
1755         for (i = 0; i < qp->tx_max_entry; i++) {
1756                 entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
1757                 if (!entry)
1758                         goto err2;
1759
1760                 entry->qp = qp;
1761                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1762                              &qp->tx_free_q);
1763         }
1764
1765         ntb_db_clear(qp->ndev, qp_bit);
1766         ntb_db_clear_mask(qp->ndev, qp_bit);
1767
1768         dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
1769
1770         return qp;
1771
1772 err2:
1773         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1774                 kfree(entry);
1775 err1:
1776         qp->rx_alloc_entry = 0;
1777         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1778                 kfree(entry);
1779         if (qp->tx_dma_chan)
1780                 dma_release_channel(qp->tx_dma_chan);
1781         if (qp->rx_dma_chan)
1782                 dma_release_channel(qp->rx_dma_chan);
1783         nt->qp_bitmap_free |= qp_bit;
1784 err:
1785         return NULL;
1786 }
1787 EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
1788
1789 /**
1790  * ntb_transport_free_queue - Frees NTB transport queue
1791  * @qp: NTB queue to be freed
1792  *
1793  * Frees NTB transport queue
1794  */
1795 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
1796 {
1797         struct pci_dev *pdev;
1798         struct ntb_queue_entry *entry;
1799         u64 qp_bit;
1800
1801         if (!qp)
1802                 return;
1803
1804         pdev = qp->ndev->pdev;
1805
1806         qp->active = false;
1807
1808         if (qp->tx_dma_chan) {
1809                 struct dma_chan *chan = qp->tx_dma_chan;
1810                 /* Putting the dma_chan to NULL will force any new traffic to be
1811                  * processed by the CPU instead of the DAM engine
1812                  */
1813                 qp->tx_dma_chan = NULL;
1814
1815                 /* Try to be nice and wait for any queued DMA engine
1816                  * transactions to process before smashing it with a rock
1817                  */
1818                 dma_sync_wait(chan, qp->last_cookie);
1819                 dmaengine_terminate_all(chan);
1820                 dma_release_channel(chan);
1821         }
1822
1823         if (qp->rx_dma_chan) {
1824                 struct dma_chan *chan = qp->rx_dma_chan;
1825                 /* Putting the dma_chan to NULL will force any new traffic to be
1826                  * processed by the CPU instead of the DAM engine
1827                  */
1828                 qp->rx_dma_chan = NULL;
1829
1830                 /* Try to be nice and wait for any queued DMA engine
1831                  * transactions to process before smashing it with a rock
1832                  */
1833                 dma_sync_wait(chan, qp->last_cookie);
1834                 dmaengine_terminate_all(chan);
1835                 dma_release_channel(chan);
1836         }
1837
1838         qp_bit = BIT_ULL(qp->qp_num);
1839
1840         ntb_db_set_mask(qp->ndev, qp_bit);
1841         tasklet_kill(&qp->rxc_db_work);
1842
1843         cancel_delayed_work_sync(&qp->link_work);
1844
1845         qp->cb_data = NULL;
1846         qp->rx_handler = NULL;
1847         qp->tx_handler = NULL;
1848         qp->event_handler = NULL;
1849
1850         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
1851                 kfree(entry);
1852
1853         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
1854                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
1855                 kfree(entry);
1856         }
1857
1858         while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
1859                 dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
1860                 kfree(entry);
1861         }
1862
1863         while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
1864                 kfree(entry);
1865
1866         qp->transport->qp_bitmap_free |= qp_bit;
1867
1868         dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
1869 }
1870 EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
1871
1872 /**
1873  * ntb_transport_rx_remove - Dequeues enqueued rx packet
1874  * @qp: NTB queue to be freed
1875  * @len: pointer to variable to write enqueued buffers length
1876  *
1877  * Dequeues unused buffers from receive queue.  Should only be used during
1878  * shutdown of qp.
1879  *
1880  * RETURNS: NULL error value on error, or void* for success.
1881  */
1882 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
1883 {
1884         struct ntb_queue_entry *entry;
1885         void *buf;
1886
1887         if (!qp || qp->client_ready)
1888                 return NULL;
1889
1890         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
1891         if (!entry)
1892                 return NULL;
1893
1894         buf = entry->cb_data;
1895         *len = entry->len;
1896
1897         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
1898
1899         return buf;
1900 }
1901 EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
1902
1903 /**
1904  * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
1905  * @qp: NTB transport layer queue the entry is to be enqueued on
1906  * @cb: per buffer pointer for callback function to use
1907  * @data: pointer to data buffer that incoming packets will be copied into
1908  * @len: length of the data buffer
1909  *
1910  * Enqueue a new receive buffer onto the transport queue into which a NTB
1911  * payload can be received into.
1912  *
1913  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1914  */
1915 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1916                              unsigned int len)
1917 {
1918         struct ntb_queue_entry *entry;
1919
1920         if (!qp)
1921                 return -EINVAL;
1922
1923         entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
1924         if (!entry)
1925                 return -ENOMEM;
1926
1927         entry->cb_data = cb;
1928         entry->buf = data;
1929         entry->len = len;
1930         entry->flags = 0;
1931
1932         ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
1933
1934         if (qp->active)
1935                 tasklet_schedule(&qp->rxc_db_work);
1936
1937         return 0;
1938 }
1939 EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
1940
1941 /**
1942  * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
1943  * @qp: NTB transport layer queue the entry is to be enqueued on
1944  * @cb: per buffer pointer for callback function to use
1945  * @data: pointer to data buffer that will be sent
1946  * @len: length of the data buffer
1947  *
1948  * Enqueue a new transmit buffer onto the transport queue from which a NTB
1949  * payload will be transmitted.  This assumes that a lock is being held to
1950  * serialize access to the qp.
1951  *
1952  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
1953  */
1954 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
1955                              unsigned int len)
1956 {
1957         struct ntb_queue_entry *entry;
1958         int rc;
1959
1960         if (!qp || !qp->link_is_up || !len)
1961                 return -EINVAL;
1962
1963         entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
1964         if (!entry) {
1965                 qp->tx_err_no_buf++;
1966                 return -EBUSY;
1967         }
1968
1969         entry->cb_data = cb;
1970         entry->buf = data;
1971         entry->len = len;
1972         entry->flags = 0;
1973
1974         rc = ntb_process_tx(qp, entry);
1975         if (rc)
1976                 ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
1977                              &qp->tx_free_q);
1978
1979         return rc;
1980 }
1981 EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
1982
1983 /**
1984  * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
1985  * @qp: NTB transport layer queue to be enabled
1986  *
1987  * Notify NTB transport layer of client readiness to use queue
1988  */
1989 void ntb_transport_link_up(struct ntb_transport_qp *qp)
1990 {
1991         if (!qp)
1992                 return;
1993
1994         qp->client_ready = true;
1995
1996         if (qp->transport->link_is_up)
1997                 schedule_delayed_work(&qp->link_work, 0);
1998 }
1999 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
2000
2001 /**
2002  * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
2003  * @qp: NTB transport layer queue to be disabled
2004  *
2005  * Notify NTB transport layer of client's desire to no longer receive data on
2006  * transport queue specified.  It is the client's responsibility to ensure all
2007  * entries on queue are purged or otherwise handled appropriately.
2008  */
2009 void ntb_transport_link_down(struct ntb_transport_qp *qp)
2010 {
2011         int val;
2012
2013         if (!qp)
2014                 return;
2015
2016         qp->client_ready = false;
2017
2018         val = ntb_spad_read(qp->ndev, QP_LINKS);
2019
2020         ntb_peer_spad_write(qp->ndev, QP_LINKS,
2021                             val & ~BIT(qp->qp_num));
2022
2023         if (qp->link_is_up)
2024                 ntb_send_link_down(qp);
2025         else
2026                 cancel_delayed_work_sync(&qp->link_work);
2027 }
2028 EXPORT_SYMBOL_GPL(ntb_transport_link_down);
2029
2030 /**
2031  * ntb_transport_link_query - Query transport link state
2032  * @qp: NTB transport layer queue to be queried
2033  *
2034  * Query connectivity to the remote system of the NTB transport queue
2035  *
2036  * RETURNS: true for link up or false for link down
2037  */
2038 bool ntb_transport_link_query(struct ntb_transport_qp *qp)
2039 {
2040         if (!qp)
2041                 return false;
2042
2043         return qp->link_is_up;
2044 }
2045 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
2046
2047 /**
2048  * ntb_transport_qp_num - Query the qp number
2049  * @qp: NTB transport layer queue to be queried
2050  *
2051  * Query qp number of the NTB transport queue
2052  *
2053  * RETURNS: a zero based number specifying the qp number
2054  */
2055 unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
2056 {
2057         if (!qp)
2058                 return 0;
2059
2060         return qp->qp_num;
2061 }
2062 EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
2063
2064 /**
2065  * ntb_transport_max_size - Query the max payload size of a qp
2066  * @qp: NTB transport layer queue to be queried
2067  *
2068  * Query the maximum payload size permissible on the given qp
2069  *
2070  * RETURNS: the max payload size of a qp
2071  */
2072 unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
2073 {
2074         unsigned int max_size;
2075         unsigned int copy_align;
2076         struct dma_chan *rx_chan, *tx_chan;
2077
2078         if (!qp)
2079                 return 0;
2080
2081         rx_chan = qp->rx_dma_chan;
2082         tx_chan = qp->tx_dma_chan;
2083
2084         copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
2085                          tx_chan ? tx_chan->device->copy_align : 0);
2086
2087         /* If DMA engine usage is possible, try to find the max size for that */
2088         max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
2089         max_size = round_down(max_size, 1 << copy_align);
2090
2091         return max_size;
2092 }
2093 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
2094
2095 unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
2096 {
2097         unsigned int head = qp->tx_index;
2098         unsigned int tail = qp->remote_rx_info->entry;
2099
2100         return tail > head ? tail - head : qp->tx_max_entry + tail - head;
2101 }
2102 EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
2103
2104 static void ntb_transport_doorbell_callback(void *data, int vector)
2105 {
2106         struct ntb_transport_ctx *nt = data;
2107         struct ntb_transport_qp *qp;
2108         u64 db_bits;
2109         unsigned int qp_num;
2110
2111         db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
2112                    ntb_db_vector_mask(nt->ndev, vector));
2113
2114         while (db_bits) {
2115                 qp_num = __ffs(db_bits);
2116                 qp = &nt->qp_vec[qp_num];
2117
2118                 if (qp->active)
2119                         tasklet_schedule(&qp->rxc_db_work);
2120
2121                 db_bits &= ~BIT_ULL(qp_num);
2122         }
2123 }
2124
2125 static const struct ntb_ctx_ops ntb_transport_ops = {
2126         .link_event = ntb_transport_event_callback,
2127         .db_event = ntb_transport_doorbell_callback,
2128 };
2129
2130 static struct ntb_client ntb_transport_client = {
2131         .ops = {
2132                 .probe = ntb_transport_probe,
2133                 .remove = ntb_transport_free,
2134         },
2135 };
2136
2137 static int __init ntb_transport_init(void)
2138 {
2139         int rc;
2140
2141         pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
2142
2143         if (debugfs_initialized())
2144                 nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
2145
2146         rc = bus_register(&ntb_transport_bus);
2147         if (rc)
2148                 goto err_bus;
2149
2150         rc = ntb_register_client(&ntb_transport_client);
2151         if (rc)
2152                 goto err_client;
2153
2154         return 0;
2155
2156 err_client:
2157         bus_unregister(&ntb_transport_bus);
2158 err_bus:
2159         debugfs_remove_recursive(nt_debugfs_dir);
2160         return rc;
2161 }
2162 module_init(ntb_transport_init);
2163
2164 static void __exit ntb_transport_exit(void)
2165 {
2166         debugfs_remove_recursive(nt_debugfs_dir);
2167
2168         ntb_unregister_client(&ntb_transport_client);
2169         bus_unregister(&ntb_transport_bus);
2170 }
2171 module_exit(ntb_transport_exit);