drivers/ntb/test/ntb_pingpong.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) 2015 EMC Corporation. All Rights Reserved.
   8  *   Copyright (C) 2017 T-Platforms. 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  *   This program is distributed in the hope that it will be useful, but
  15  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *   General Public License for more details.
  18  *
  19  *   BSD LICENSE
  20  *
  21  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
  22  *   Copyright (C) 2017 T-Platforms. All Rights Reserved.
  23  *
  24  *   Redistribution and use in source and binary forms, with or without
  25  *   modification, are permitted provided that the following conditions
  26  *   are met:
  27  *
  28  *     * Redistributions of source code must retain the above copyright
  29  *       notice, this list of conditions and the following disclaimer.
  30  *     * Redistributions in binary form must reproduce the above copy
  31  *       notice, this list of conditions and the following disclaimer in
  32  *       the documentation and/or other materials provided with the
  33  *       distribution.
  34  *     * Neither the name of Intel Corporation nor the names of its
  35  *       contributors may be used to endorse or promote products derived
  36  *       from this software without specific prior written permission.
  37  *
  38  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  39  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  40  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  41  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  42  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  43  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  44  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  45  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  46  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  47  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  48  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  49  *
  50  * PCIe NTB Pingpong Linux driver
  51  */
  52
  53 /*
  54  * How to use this tool, by example.
  55  *
  56  * Assuming $DBG_DIR is something like:
  57  * '/sys/kernel/debug/ntb_perf/0000:00:03.0'
  58  * Suppose aside from local device there is at least one remote device
  59  * connected to NTB with index 0.
  60  *-----------------------------------------------------------------------------
  61  * Eg: install driver with specified delay between doorbell event and response
  62  *
  63  * root@self# insmod ntb_pingpong.ko delay_ms=1000
  64  *-----------------------------------------------------------------------------
  65  * Eg: get number of ping-pong cycles performed
  66  *
  67  * root@self# cat $DBG_DIR/count
  68  */
  69
  70 #include <linux/init.h>
  71 #include <linux/kernel.h>
  72 #include <linux/module.h>
  73 #include <linux/device.h>
  74 #include <linux/bitops.h>
  75
  76 #include <linux/pci.h>
  77 #include <linux/slab.h>
  78 #include <linux/hrtimer.h>
  79 #include <linux/debugfs.h>
  80
  81 #include <linux/ntb.h>
  82
  83 #define DRIVER_NAME             "ntb_pingpong"
  84 #define DRIVER_VERSION          "2.0"
  85
  86 MODULE_LICENSE("Dual BSD/GPL");
  87 MODULE_VERSION(DRIVER_VERSION);
  88 MODULE_AUTHOR("Allen Hubbe <Allen.Hubbe@emc.com>");
  89 MODULE_DESCRIPTION("PCIe NTB Simple Pingpong Client");
  90
  91 static unsigned int unsafe;
  92 module_param(unsafe, uint, 0644);
  93 MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
  94
  95 static unsigned int delay_ms = 1000;
  96 module_param(delay_ms, uint, 0644);
  97 MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
  98
  99 struct pp_ctx {
 100         struct ntb_dev *ntb;
 101         struct hrtimer timer;
 102         u64 in_db;
 103         u64 out_db;
 104         int out_pidx;
 105         u64 nmask;
 106         u64 pmask;
 107         atomic_t count;
 108         spinlock_t lock;
 109         struct dentry *dbgfs_dir;
 110 };
 111 #define to_pp_timer(__timer) \
 112         container_of(__timer, struct pp_ctx, timer)
 113
 114 static struct dentry *pp_dbgfs_topdir;
 115
 116 static int pp_find_next_peer(struct pp_ctx *pp)
 117 {
 118         u64 link, out_db;
 119         int pidx;
 120
 121         link = ntb_link_is_up(pp->ntb, NULL, NULL);
 122
 123         /* Find next available peer */
 124         if (link & pp->nmask) {
 125                 pidx = __ffs64(link & pp->nmask);
 126                 out_db = BIT_ULL(pidx + 1);
 127         } else if (link & pp->pmask) {
 128                 pidx = __ffs64(link & pp->pmask);
 129                 out_db = BIT_ULL(pidx);
 130         } else {
 131                 return -ENODEV;
 132         }
 133
 134         spin_lock(&pp->lock);
 135         pp->out_pidx = pidx;
 136         pp->out_db = out_db;
 137         spin_unlock(&pp->lock);
 138
 139         return 0;
 140 }
 141
 142 static void pp_setup(struct pp_ctx *pp)
 143 {
 144         int ret;
 145
 146         ntb_db_set_mask(pp->ntb, pp->in_db);
 147
 148         hrtimer_cancel(&pp->timer);
 149
 150         ret = pp_find_next_peer(pp);
 151         if (ret == -ENODEV) {
 152                 dev_dbg(&pp->ntb->dev, "Got no peers, so cancel\n");
 153                 return;
 154         }
 155
 156         dev_dbg(&pp->ntb->dev, "Ping-pong started with port %d, db %#llx\n",
 157                 ntb_peer_port_number(pp->ntb, pp->out_pidx), pp->out_db);
 158
 159         hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
 160 }
 161
 162 static void pp_clear(struct pp_ctx *pp)
 163 {
 164         hrtimer_cancel(&pp->timer);
 165
 166         ntb_db_set_mask(pp->ntb, pp->in_db);
 167
 168         dev_dbg(&pp->ntb->dev, "Ping-pong cancelled\n");
 169 }
 170
 171 static void pp_ping(struct pp_ctx *pp)
 172 {
 173         u32 count;
 174
 175         count = atomic_read(&pp->count);
 176
 177         spin_lock(&pp->lock);
 178         ntb_peer_spad_write(pp->ntb, pp->out_pidx, 0, count);
 179         ntb_peer_msg_write(pp->ntb, pp->out_pidx, 0, count);
 180
 181         dev_dbg(&pp->ntb->dev, "Ping port %d spad %#x, msg %#x\n",
 182                 ntb_peer_port_number(pp->ntb, pp->out_pidx), count, count);
 183
 184         ntb_peer_db_set(pp->ntb, pp->out_db);
 185         ntb_db_clear_mask(pp->ntb, pp->in_db);
 186         spin_unlock(&pp->lock);
 187 }
 188
 189 static void pp_pong(struct pp_ctx *pp)
 190 {
 191         u32 msg_data = -1, spad_data = -1;
 192         int pidx = 0;
 193
 194         /* Read pong data */
 195         spad_data = ntb_spad_read(pp->ntb, 0);
 196         msg_data = ntb_msg_read(pp->ntb, &pidx, 0);
 197         ntb_msg_clear_sts(pp->ntb, -1);
 198
 199         /*
 200          * Scratchpad and message data may differ, since message register can't
 201          * be rewritten unless status is cleared. Additionally either of them
 202          * might be unsupported
 203          */
 204         dev_dbg(&pp->ntb->dev, "Pong spad %#x, msg %#x (port %d)\n",
 205                 spad_data, msg_data, ntb_peer_port_number(pp->ntb, pidx));
 206
 207         atomic_inc(&pp->count);
 208
 209         ntb_db_set_mask(pp->ntb, pp->in_db);
 210         ntb_db_clear(pp->ntb, pp->in_db);
 211
 212         hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
 213 }
 214
 215 static enum hrtimer_restart pp_timer_func(struct hrtimer *t)
 216 {
 217         struct pp_ctx *pp = to_pp_timer(t);
 218
 219         pp_ping(pp);
 220
 221         return HRTIMER_NORESTART;
 222 }
 223
 224 static void pp_link_event(void *ctx)
 225 {
 226         struct pp_ctx *pp = ctx;
 227
 228         pp_setup(pp);
 229 }
 230
 231 static void pp_db_event(void *ctx, int vec)
 232 {
 233         struct pp_ctx *pp = ctx;
 234
 235         pp_pong(pp);
 236 }
 237
 238 static const struct ntb_ctx_ops pp_ops = {
 239         .link_event = pp_link_event,
 240         .db_event = pp_db_event
 241 };
 242
 243 static int pp_check_ntb(struct ntb_dev *ntb)
 244 {
 245         u64 pmask;
 246
 247         if (ntb_db_is_unsafe(ntb)) {
 248                 dev_dbg(&ntb->dev, "Doorbell is unsafe\n");
 249                 if (!unsafe)
 250                         return -EINVAL;
 251         }
 252
 253         if (ntb_spad_is_unsafe(ntb)) {
 254                 dev_dbg(&ntb->dev, "Scratchpad is unsafe\n");
 255                 if (!unsafe)
 256                         return -EINVAL;
 257         }
 258
 259         pmask = GENMASK_ULL(ntb_peer_port_count(ntb), 0);
 260         if ((ntb_db_valid_mask(ntb) & pmask) != pmask) {
 261                 dev_err(&ntb->dev, "Unsupported DB configuration\n");
 262                 return -EINVAL;
 263         }
 264
 265         if (ntb_spad_count(ntb) < 1 && ntb_msg_count(ntb) < 1) {
 266                 dev_err(&ntb->dev, "Scratchpads and messages unsupported\n");
 267                 return -EINVAL;
 268         } else if (ntb_spad_count(ntb) < 1) {
 269                 dev_dbg(&ntb->dev, "Scratchpads unsupported\n");
 270         } else if (ntb_msg_count(ntb) < 1) {
 271                 dev_dbg(&ntb->dev, "Messages unsupported\n");
 272         }
 273
 274         return 0;
 275 }
 276
 277 static struct pp_ctx *pp_create_data(struct ntb_dev *ntb)
 278 {
 279         struct pp_ctx *pp;
 280
 281         pp = devm_kzalloc(&ntb->dev, sizeof(*pp), GFP_KERNEL);
 282         if (!pp)
 283                 return ERR_PTR(-ENOMEM);
 284
 285         pp->ntb = ntb;
 286         atomic_set(&pp->count, 0);
 287         spin_lock_init(&pp->lock);
 288         hrtimer_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 289         pp->timer.function = pp_timer_func;
 290
 291         return pp;
 292 }
 293
 294 static void pp_init_flds(struct pp_ctx *pp)
 295 {
 296         int pidx, lport, pcnt;
 297
 298         /* Find global port index */
 299         lport = ntb_port_number(pp->ntb);
 300         pcnt = ntb_peer_port_count(pp->ntb);
 301         for (pidx = 0; pidx < pcnt; pidx++) {
 302                 if (lport < ntb_peer_port_number(pp->ntb, pidx))
 303                         break;
 304         }
 305
 306         pp->in_db = BIT_ULL(pidx);
 307         pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
 308         pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
 309
 310         dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
 311                 pp->in_db, pp->pmask, pp->nmask);
 312 }
 313
 314 static int pp_mask_events(struct pp_ctx *pp)
 315 {
 316         u64 db_mask, msg_mask;
 317         int ret;
 318
 319         db_mask = ntb_db_valid_mask(pp->ntb);
 320         ret = ntb_db_set_mask(pp->ntb, db_mask);
 321         if (ret)
 322                 return ret;
 323
 324         /* Skip message events masking if unsupported */
 325         if (ntb_msg_count(pp->ntb) < 1)
 326                 return 0;
 327
 328         msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
 329         return ntb_msg_set_mask(pp->ntb, msg_mask);
 330 }
 331
 332 static int pp_setup_ctx(struct pp_ctx *pp)
 333 {
 334         int ret;
 335
 336         ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
 337         if (ret)
 338                 return ret;
 339
 340         ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
 341         /* Might be not necessary */
 342         ntb_link_event(pp->ntb);
 343
 344         return 0;
 345 }
 346
 347 static void pp_clear_ctx(struct pp_ctx *pp)
 348 {
 349         ntb_link_disable(pp->ntb);
 350
 351         ntb_clear_ctx(pp->ntb);
 352 }
 353
 354 static void pp_setup_dbgfs(struct pp_ctx *pp)
 355 {
 356         struct pci_dev *pdev = pp->ntb->pdev;
 357         void *ret;
 358
 359         pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
 360
 361         ret = debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
 362         if (!ret)
 363                 dev_warn(&pp->ntb->dev, "DebugFS unsupported\n");
 364 }
 365
 366 static void pp_clear_dbgfs(struct pp_ctx *pp)
 367 {
 368         debugfs_remove_recursive(pp->dbgfs_dir);
 369 }
 370
 371 static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
 372 {
 373         struct pp_ctx *pp;
 374         int ret;
 375
 376         ret = pp_check_ntb(ntb);
 377         if (ret)
 378                 return ret;
 379
 380         pp = pp_create_data(ntb);
 381         if (IS_ERR(pp))
 382                 return PTR_ERR(pp);
 383
 384         pp_init_flds(pp);
 385
 386         ret = pp_mask_events(pp);
 387         if (ret)
 388                 return ret;
 389
 390         ret = pp_setup_ctx(pp);
 391         if (ret)
 392                 return ret;
 393
 394         pp_setup_dbgfs(pp);
 395
 396         return 0;
 397 }
 398
 399 static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
 400 {
 401         struct pp_ctx *pp = ntb->ctx;
 402
 403         pp_clear_dbgfs(pp);
 404
 405         pp_clear_ctx(pp);
 406
 407         pp_clear(pp);
 408 }
 409
 410 static struct ntb_client pp_client = {
 411         .ops = {
 412                 .probe = pp_probe,
 413                 .remove = pp_remove
 414         }
 415 };
 416
 417 static int __init pp_init(void)
 418 {
 419         int ret;
 420
 421         if (debugfs_initialized())
 422                 pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 423
 424         ret = ntb_register_client(&pp_client);
 425         if (ret)
 426                 debugfs_remove_recursive(pp_dbgfs_topdir);
 427
 428         return ret;
 429 }
 430 module_init(pp_init);
 431
 432 static void __exit pp_exit(void)
 433 {
 434         ntb_unregister_client(&pp_client);
 435         debugfs_remove_recursive(pp_dbgfs_topdir);
 436 }
 437 module_exit(pp_exit);
 438