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  *
   9  *   This program is free software; you can redistribute it and/or modify
  10  *   it under the terms of version 2 of the GNU General Public License as
  11  *   published by the Free Software Foundation.
  12  *
  13  *   This program is distributed in the hope that it will be useful, but
  14  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  *   General Public License for more details.
  17  *
  18  *   BSD LICENSE
  19  *
  20  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
  21  *
  22  *   Redistribution and use in source and binary forms, with or without
  23  *   modification, are permitted provided that the following conditions
  24  *   are met:
  25  *
  26  *     * Redistributions of source code must retain the above copyright
  27  *       notice, this list of conditions and the following disclaimer.
  28  *     * Redistributions in binary form must reproduce the above copy
  29  *       notice, this list of conditions and the following disclaimer in
  30  *       the documentation and/or other materials provided with the
  31  *       distribution.
  32  *     * Neither the name of Intel Corporation nor the names of its
  33  *       contributors may be used to endorse or promote products derived
  34  *       from this software without specific prior written permission.
  35  *
  36  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  37  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  38  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  39  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  40  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  42  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  43  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  44  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  45  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  46  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  47  *
  48  * PCIe NTB Pingpong Linux driver
  49  *
  50  * Contact Information:
  51  * Allen Hubbe <Allen.Hubbe@emc.com>
  52  */
  53
  54 /* Note: load this module with option 'dyndbg=+p' */
  55
  56 #include <linux/init.h>
  57 #include <linux/kernel.h>
  58 #include <linux/module.h>
  59
  60 #include <linux/dma-mapping.h>
  61 #include <linux/pci.h>
  62 #include <linux/slab.h>
  63 #include <linux/spinlock.h>
  64 #include <linux/debugfs.h>
  65
  66 #include <linux/ntb.h>
  67
  68 #define DRIVER_NAME                     "ntb_pingpong"
  69 #define DRIVER_DESCRIPTION              "PCIe NTB Simple Pingpong Client"
  70
  71 #define DRIVER_LICENSE                  "Dual BSD/GPL"
  72 #define DRIVER_VERSION                  "1.0"
  73 #define DRIVER_RELDATE                  "24 March 2015"
  74 #define DRIVER_AUTHOR                   "Allen Hubbe <Allen.Hubbe@emc.com>"
  75
  76 MODULE_LICENSE(DRIVER_LICENSE);
  77 MODULE_VERSION(DRIVER_VERSION);
  78 MODULE_AUTHOR(DRIVER_AUTHOR);
  79 MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
  80
  81 static unsigned int unsafe;
  82 module_param(unsafe, uint, 0644);
  83 MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
  84
  85 static unsigned int delay_ms = 1000;
  86 module_param(delay_ms, uint, 0644);
  87 MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
  88
  89 static unsigned long db_init = 0x7;
  90 module_param(db_init, ulong, 0644);
  91 MODULE_PARM_DESC(db_init, "Initial doorbell bits to ring on the peer");
  92
  93 struct pp_ctx {
  94         struct ntb_dev                  *ntb;
  95         u64                             db_bits;
  96         /* synchronize access to db_bits by ping and pong */
  97         spinlock_t                      db_lock;
  98         struct timer_list               db_timer;
  99         unsigned long                   db_delay;
 100         struct dentry                   *debugfs_node_dir;
 101         struct dentry                   *debugfs_count;
 102         atomic_t                        count;
 103 };
 104
 105 static struct dentry *pp_debugfs_dir;
 106
 107 static void pp_ping(unsigned long ctx)
 108 {
 109         struct pp_ctx *pp = (void *)ctx;
 110         unsigned long irqflags;
 111         u64 db_bits, db_mask;
 112         u32 spad_rd, spad_wr;
 113
 114         spin_lock_irqsave(&pp->db_lock, irqflags);
 115         {
 116                 db_mask = ntb_db_valid_mask(pp->ntb);
 117                 db_bits = ntb_db_read(pp->ntb);
 118
 119                 if (db_bits) {
 120                         dev_dbg(&pp->ntb->dev,
 121                                 "Masked pongs %#llx\n",
 122                                 db_bits);
 123                         ntb_db_clear(pp->ntb, db_bits);
 124                 }
 125
 126                 db_bits = ((pp->db_bits | db_bits) << 1) & db_mask;
 127
 128                 if (!db_bits)
 129                         db_bits = db_init;
 130
 131                 spad_rd = ntb_spad_read(pp->ntb, 0);
 132                 spad_wr = spad_rd + 1;
 133
 134                 dev_dbg(&pp->ntb->dev,
 135                         "Ping bits %#llx read %#x write %#x\n",
 136                         db_bits, spad_rd, spad_wr);
 137
 138                 ntb_peer_spad_write(pp->ntb, 0, spad_wr);
 139                 ntb_peer_db_set(pp->ntb, db_bits);
 140                 ntb_db_clear_mask(pp->ntb, db_mask);
 141
 142                 pp->db_bits = 0;
 143         }
 144         spin_unlock_irqrestore(&pp->db_lock, irqflags);
 145 }
 146
 147 static void pp_link_event(void *ctx)
 148 {
 149         struct pp_ctx *pp = ctx;
 150
 151         if (ntb_link_is_up(pp->ntb, NULL, NULL) == 1) {
 152                 dev_dbg(&pp->ntb->dev, "link is up\n");
 153                 pp_ping((unsigned long)pp);
 154         } else {
 155                 dev_dbg(&pp->ntb->dev, "link is down\n");
 156                 del_timer(&pp->db_timer);
 157         }
 158 }
 159
 160 static void pp_db_event(void *ctx, int vec)
 161 {
 162         struct pp_ctx *pp = ctx;
 163         u64 db_bits, db_mask;
 164         unsigned long irqflags;
 165
 166         spin_lock_irqsave(&pp->db_lock, irqflags);
 167         {
 168                 db_mask = ntb_db_vector_mask(pp->ntb, vec);
 169                 db_bits = db_mask & ntb_db_read(pp->ntb);
 170                 ntb_db_set_mask(pp->ntb, db_mask);
 171                 ntb_db_clear(pp->ntb, db_bits);
 172
 173                 pp->db_bits |= db_bits;
 174
 175                 mod_timer(&pp->db_timer, jiffies + pp->db_delay);
 176
 177                 dev_dbg(&pp->ntb->dev,
 178                         "Pong vec %d bits %#llx\n",
 179                         vec, db_bits);
 180                 atomic_inc(&pp->count);
 181         }
 182         spin_unlock_irqrestore(&pp->db_lock, irqflags);
 183 }
 184
 185 static int pp_debugfs_setup(struct pp_ctx *pp)
 186 {
 187         struct pci_dev *pdev = pp->ntb->pdev;
 188
 189         if (!pp_debugfs_dir)
 190                 return -ENODEV;
 191
 192         pp->debugfs_node_dir = debugfs_create_dir(pci_name(pdev),
 193                                                   pp_debugfs_dir);
 194         if (!pp->debugfs_node_dir)
 195                 return -ENODEV;
 196
 197         pp->debugfs_count = debugfs_create_atomic_t("count", S_IRUSR | S_IWUSR,
 198                                                     pp->debugfs_node_dir,
 199                                                     &pp->count);
 200         if (!pp->debugfs_count)
 201                 return -ENODEV;
 202
 203         return 0;
 204 }
 205
 206 static const struct ntb_ctx_ops pp_ops = {
 207         .link_event = pp_link_event,
 208         .db_event = pp_db_event,
 209 };
 210
 211 static int pp_probe(struct ntb_client *client,
 212                     struct ntb_dev *ntb)
 213 {
 214         struct pp_ctx *pp;
 215         int rc;
 216
 217         if (ntb_db_is_unsafe(ntb)) {
 218                 dev_dbg(&ntb->dev, "doorbell is unsafe\n");
 219                 if (!unsafe) {
 220                         rc = -EINVAL;
 221                         goto err_pp;
 222                 }
 223         }
 224
 225         if (ntb_spad_is_unsafe(ntb)) {
 226                 dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
 227                 if (!unsafe) {
 228                         rc = -EINVAL;
 229                         goto err_pp;
 230                 }
 231         }
 232
 233         pp = kmalloc(sizeof(*pp), GFP_KERNEL);
 234         if (!pp) {
 235                 rc = -ENOMEM;
 236                 goto err_pp;
 237         }
 238
 239         pp->ntb = ntb;
 240         pp->db_bits = 0;
 241         atomic_set(&pp->count, 0);
 242         spin_lock_init(&pp->db_lock);
 243         setup_timer(&pp->db_timer, pp_ping, (unsigned long)pp);
 244         pp->db_delay = msecs_to_jiffies(delay_ms);
 245
 246         rc = ntb_set_ctx(ntb, pp, &pp_ops);
 247         if (rc)
 248                 goto err_ctx;
 249
 250         rc = pp_debugfs_setup(pp);
 251         if (rc)
 252                 goto err_ctx;
 253
 254         ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
 255         ntb_link_event(ntb);
 256
 257         return 0;
 258
 259 err_ctx:
 260         kfree(pp);
 261 err_pp:
 262         return rc;
 263 }
 264
 265 static void pp_remove(struct ntb_client *client,
 266                       struct ntb_dev *ntb)
 267 {
 268         struct pp_ctx *pp = ntb->ctx;
 269
 270         debugfs_remove_recursive(pp->debugfs_node_dir);
 271
 272         ntb_clear_ctx(ntb);
 273         del_timer_sync(&pp->db_timer);
 274         ntb_link_disable(ntb);
 275
 276         kfree(pp);
 277 }
 278
 279 static struct ntb_client pp_client = {
 280         .ops = {
 281                 .probe = pp_probe,
 282                 .remove = pp_remove,
 283         },
 284 };
 285
 286 static int __init pp_init(void)
 287 {
 288         int rc;
 289
 290         if (debugfs_initialized())
 291                 pp_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 292
 293         rc = ntb_register_client(&pp_client);
 294         if (rc)
 295                 goto err_client;
 296
 297         return 0;
 298
 299 err_client:
 300         debugfs_remove_recursive(pp_debugfs_dir);
 301         return rc;
 302 }
 303 module_init(pp_init);
 304
 305 static void __exit pp_exit(void)
 306 {
 307         ntb_unregister_client(&pp_client);
 308         debugfs_remove_recursive(pp_debugfs_dir);
 309 }
 310 module_exit(pp_exit);