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         else if (link & pp->pmask)
 127                 pidx = __ffs64(link & pp->pmask);
 128         else
 129                 return -ENODEV;
 130
 131         out_db = BIT_ULL(ntb_peer_port_number(pp->ntb, pidx));
 132
 133         spin_lock(&pp->lock);
 134         pp->out_pidx = pidx;
 135         pp->out_db = out_db;
 136         spin_unlock(&pp->lock);
 137
 138         return 0;
 139 }
 140
 141 static void pp_setup(struct pp_ctx *pp)
 142 {
 143         int ret;
 144
 145         ntb_db_set_mask(pp->ntb, pp->in_db);
 146
 147         hrtimer_cancel(&pp->timer);
 148
 149         ret = pp_find_next_peer(pp);
 150         if (ret == -ENODEV) {
 151                 dev_dbg(&pp->ntb->dev, "Got no peers, so cancel\n");
 152                 return;
 153         }
 154
 155         dev_dbg(&pp->ntb->dev, "Ping-pong started with port %d, db %#llx\n",
 156                 ntb_peer_port_number(pp->ntb, pp->out_pidx), pp->out_db);
 157
 158         hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
 159 }
 160
 161 static void pp_clear(struct pp_ctx *pp)
 162 {
 163         hrtimer_cancel(&pp->timer);
 164
 165         ntb_db_set_mask(pp->ntb, pp->in_db);
 166
 167         dev_dbg(&pp->ntb->dev, "Ping-pong cancelled\n");
 168 }
 169
 170 static void pp_ping(struct pp_ctx *pp)
 171 {
 172         u32 count;
 173
 174         count = atomic_read(&pp->count);
 175
 176         spin_lock(&pp->lock);
 177         ntb_peer_spad_write(pp->ntb, pp->out_pidx, 0, count);
 178         ntb_peer_msg_write(pp->ntb, pp->out_pidx, 0, count);
 179
 180         dev_dbg(&pp->ntb->dev, "Ping port %d spad %#x, msg %#x\n",
 181                 ntb_peer_port_number(pp->ntb, pp->out_pidx), count, count);
 182
 183         ntb_peer_db_set(pp->ntb, pp->out_db);
 184         ntb_db_clear_mask(pp->ntb, pp->in_db);
 185         spin_unlock(&pp->lock);
 186 }
 187
 188 static void pp_pong(struct pp_ctx *pp)
 189 {
 190         u32 msg_data, spad_data;
 191         int pidx = 0;
 192
 193         /* Read pong data */
 194         spad_data = ntb_spad_read(pp->ntb, 0);
 195         msg_data = ntb_msg_read(pp->ntb, &pidx, 0);
 196         ntb_msg_clear_sts(pp->ntb, -1);
 197
 198         /*
 199          * Scratchpad and message data may differ, since message register can't
 200          * be rewritten unless status is cleared. Additionally either of them
 201          * might be unsupported
 202          */
 203         dev_dbg(&pp->ntb->dev, "Pong spad %#x, msg %#x (port %d)\n",
 204                 spad_data, msg_data, ntb_peer_port_number(pp->ntb, pidx));
 205
 206         atomic_inc(&pp->count);
 207
 208         ntb_db_set_mask(pp->ntb, pp->in_db);
 209         ntb_db_clear(pp->ntb, pp->in_db);
 210
 211         hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
 212 }
 213
 214 static enum hrtimer_restart pp_timer_func(struct hrtimer *t)
 215 {
 216         struct pp_ctx *pp = to_pp_timer(t);
 217
 218         pp_ping(pp);
 219
 220         return HRTIMER_NORESTART;
 221 }
 222
 223 static void pp_link_event(void *ctx)
 224 {
 225         struct pp_ctx *pp = ctx;
 226
 227         pp_setup(pp);
 228 }
 229
 230 static void pp_db_event(void *ctx, int vec)
 231 {
 232         struct pp_ctx *pp = ctx;
 233
 234         pp_pong(pp);
 235 }
 236
 237 static const struct ntb_ctx_ops pp_ops = {
 238         .link_event = pp_link_event,
 239         .db_event = pp_db_event
 240 };
 241
 242 static int pp_check_ntb(struct ntb_dev *ntb)
 243 {
 244         u64 pmask;
 245
 246         if (ntb_db_is_unsafe(ntb)) {
 247                 dev_dbg(&ntb->dev, "Doorbell is unsafe\n");
 248                 if (!unsafe)
 249                         return -EINVAL;
 250         }
 251
 252         if (ntb_spad_is_unsafe(ntb)) {
 253                 dev_dbg(&ntb->dev, "Scratchpad is unsafe\n");
 254                 if (!unsafe)
 255                         return -EINVAL;
 256         }
 257
 258         pmask = GENMASK_ULL(ntb_peer_port_count(ntb), 0);
 259         if ((ntb_db_valid_mask(ntb) & pmask) != pmask) {
 260                 dev_err(&ntb->dev, "Unsupported DB configuration\n");
 261                 return -EINVAL;
 262         }
 263
 264         if (ntb_spad_count(ntb) < 1 && ntb_msg_count(ntb) < 1) {
 265                 dev_err(&ntb->dev, "Scratchpads and messages unsupported\n");
 266                 return -EINVAL;
 267         } else if (ntb_spad_count(ntb) < 1) {
 268                 dev_dbg(&ntb->dev, "Scratchpads unsupported\n");
 269         } else if (ntb_msg_count(ntb) < 1) {
 270                 dev_dbg(&ntb->dev, "Messages unsupported\n");
 271         }
 272
 273         return 0;
 274 }
 275
 276 static struct pp_ctx *pp_create_data(struct ntb_dev *ntb)
 277 {
 278         struct pp_ctx *pp;
 279
 280         pp = devm_kzalloc(&ntb->dev, sizeof(*pp), GFP_KERNEL);
 281         if (!pp)
 282                 return ERR_PTR(-ENOMEM);
 283
 284         pp->ntb = ntb;
 285         atomic_set(&pp->count, 0);
 286         spin_lock_init(&pp->lock);
 287         hrtimer_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 288         pp->timer.function = pp_timer_func;
 289
 290         return pp;
 291 }
 292
 293 static void pp_init_flds(struct pp_ctx *pp)
 294 {
 295         int pidx, lport, pcnt;
 296
 297         /* Find global port index */
 298         lport = ntb_port_number(pp->ntb);
 299         pcnt = ntb_peer_port_count(pp->ntb);
 300         for (pidx = 0; pidx < pcnt; pidx++) {
 301                 if (lport < ntb_peer_port_number(pp->ntb, pidx))
 302                         break;
 303         }
 304
 305         pp->in_db = BIT_ULL(lport);
 306         pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
 307         pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
 308
 309         dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
 310                 pp->in_db, pp->pmask, pp->nmask);
 311 }
 312
 313 static int pp_mask_events(struct pp_ctx *pp)
 314 {
 315         u64 db_mask, msg_mask;
 316         int ret;
 317
 318         db_mask = ntb_db_valid_mask(pp->ntb);
 319         ret = ntb_db_set_mask(pp->ntb, db_mask);
 320         if (ret)
 321                 return ret;
 322
 323         /* Skip message events masking if unsupported */
 324         if (ntb_msg_count(pp->ntb) < 1)
 325                 return 0;
 326
 327         msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
 328         return ntb_msg_set_mask(pp->ntb, msg_mask);
 329 }
 330
 331 static int pp_setup_ctx(struct pp_ctx *pp)
 332 {
 333         int ret;
 334
 335         ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
 336         if (ret)
 337                 return ret;
 338
 339         ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
 340         /* Might be not necessary */
 341         ntb_link_event(pp->ntb);
 342
 343         return 0;
 344 }
 345
 346 static void pp_clear_ctx(struct pp_ctx *pp)
 347 {
 348         ntb_link_disable(pp->ntb);
 349
 350         ntb_clear_ctx(pp->ntb);
 351 }
 352
 353 static void pp_setup_dbgfs(struct pp_ctx *pp)
 354 {
 355         struct pci_dev *pdev = pp->ntb->pdev;
 356
 357         pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
 358
 359         debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
 360 }
 361
 362 static void pp_clear_dbgfs(struct pp_ctx *pp)
 363 {
 364         debugfs_remove_recursive(pp->dbgfs_dir);
 365 }
 366
 367 static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
 368 {
 369         struct pp_ctx *pp;
 370         int ret;
 371
 372         ret = pp_check_ntb(ntb);
 373         if (ret)
 374                 return ret;
 375
 376         pp = pp_create_data(ntb);
 377         if (IS_ERR(pp))
 378                 return PTR_ERR(pp);
 379
 380         pp_init_flds(pp);
 381
 382         ret = pp_mask_events(pp);
 383         if (ret)
 384                 return ret;
 385
 386         ret = pp_setup_ctx(pp);
 387         if (ret)
 388                 return ret;
 389
 390         pp_setup_dbgfs(pp);
 391
 392         return 0;
 393 }
 394
 395 static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
 396 {
 397         struct pp_ctx *pp = ntb->ctx;
 398
 399         pp_clear_dbgfs(pp);
 400
 401         pp_clear_ctx(pp);
 402
 403         pp_clear(pp);
 404 }
 405
 406 static struct ntb_client pp_client = {
 407         .ops = {
 408                 .probe = pp_probe,
 409                 .remove = pp_remove
 410         }
 411 };
 412
 413 static int __init pp_init(void)
 414 {
 415         int ret;
 416
 417         if (debugfs_initialized())
 418                 pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 419
 420         ret = ntb_register_client(&pp_client);
 421         if (ret)
 422                 debugfs_remove_recursive(pp_dbgfs_topdir);
 423
 424         return ret;
 425 }
 426 module_init(pp_init);
 427
 428 static void __exit pp_exit(void)
 429 {
 430         ntb_unregister_client(&pp_client);
 431         debugfs_remove_recursive(pp_dbgfs_topdir);
 432 }
 433 module_exit(pp_exit);