ntb_pingpong.c 10 KB

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  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. * How to use this tool, by example.
  54. *
  55. * Assuming $DBG_DIR is something like:
  56. * '/sys/kernel/debug/ntb_perf/0000:00:03.0'
  57. * Suppose aside from local device there is at least one remote device
  58. * connected to NTB with index 0.
  59. *-----------------------------------------------------------------------------
  60. * Eg: install driver with specified delay between doorbell event and response
  61. *
  62. * root@self# insmod ntb_pingpong.ko delay_ms=1000
  63. *-----------------------------------------------------------------------------
  64. * Eg: get number of ping-pong cycles performed
  65. *
  66. * root@self# cat $DBG_DIR/count
  67. */
  68. #include <linux/init.h>
  69. #include <linux/kernel.h>
  70. #include <linux/module.h>
  71. #include <linux/device.h>
  72. #include <linux/bitops.h>
  73. #include <linux/pci.h>
  74. #include <linux/slab.h>
  75. #include <linux/hrtimer.h>
  76. #include <linux/debugfs.h>
  77. #include <linux/ntb.h>
  78. #define DRIVER_NAME "ntb_pingpong"
  79. #define DRIVER_VERSION "2.0"
  80. MODULE_LICENSE("Dual BSD/GPL");
  81. MODULE_VERSION(DRIVER_VERSION);
  82. MODULE_AUTHOR("Allen Hubbe <Allen.Hubbe@emc.com>");
  83. MODULE_DESCRIPTION("PCIe NTB Simple Pingpong Client");
  84. static unsigned int unsafe;
  85. module_param(unsafe, uint, 0644);
  86. MODULE_PARM_DESC(unsafe, "Run even though ntb operations may be unsafe");
  87. static unsigned int delay_ms = 1000;
  88. module_param(delay_ms, uint, 0644);
  89. MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
  90. struct pp_ctx {
  91. struct ntb_dev *ntb;
  92. struct hrtimer timer;
  93. u64 in_db;
  94. u64 out_db;
  95. int out_pidx;
  96. u64 nmask;
  97. u64 pmask;
  98. atomic_t count;
  99. spinlock_t lock;
  100. struct dentry *dbgfs_dir;
  101. };
  102. #define to_pp_timer(__timer) \
  103. container_of(__timer, struct pp_ctx, timer)
  104. static struct dentry *pp_dbgfs_topdir;
  105. static int pp_find_next_peer(struct pp_ctx *pp)
  106. {
  107. u64 link, out_db;
  108. int pidx;
  109. link = ntb_link_is_up(pp->ntb, NULL, NULL);
  110. /* Find next available peer */
  111. if (link & pp->nmask)
  112. pidx = __ffs64(link & pp->nmask);
  113. else if (link & pp->pmask)
  114. pidx = __ffs64(link & pp->pmask);
  115. else
  116. return -ENODEV;
  117. out_db = BIT_ULL(ntb_peer_port_number(pp->ntb, pidx));
  118. spin_lock(&pp->lock);
  119. pp->out_pidx = pidx;
  120. pp->out_db = out_db;
  121. spin_unlock(&pp->lock);
  122. return 0;
  123. }
  124. static void pp_setup(struct pp_ctx *pp)
  125. {
  126. int ret;
  127. ntb_db_set_mask(pp->ntb, pp->in_db);
  128. hrtimer_cancel(&pp->timer);
  129. ret = pp_find_next_peer(pp);
  130. if (ret == -ENODEV) {
  131. dev_dbg(&pp->ntb->dev, "Got no peers, so cancel\n");
  132. return;
  133. }
  134. dev_dbg(&pp->ntb->dev, "Ping-pong started with port %d, db %#llx\n",
  135. ntb_peer_port_number(pp->ntb, pp->out_pidx), pp->out_db);
  136. hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
  137. }
  138. static void pp_clear(struct pp_ctx *pp)
  139. {
  140. hrtimer_cancel(&pp->timer);
  141. ntb_db_set_mask(pp->ntb, pp->in_db);
  142. dev_dbg(&pp->ntb->dev, "Ping-pong cancelled\n");
  143. }
  144. static void pp_ping(struct pp_ctx *pp)
  145. {
  146. u32 count;
  147. count = atomic_read(&pp->count);
  148. spin_lock(&pp->lock);
  149. ntb_peer_spad_write(pp->ntb, pp->out_pidx, 0, count);
  150. ntb_peer_msg_write(pp->ntb, pp->out_pidx, 0, count);
  151. dev_dbg(&pp->ntb->dev, "Ping port %d spad %#x, msg %#x\n",
  152. ntb_peer_port_number(pp->ntb, pp->out_pidx), count, count);
  153. ntb_peer_db_set(pp->ntb, pp->out_db);
  154. ntb_db_clear_mask(pp->ntb, pp->in_db);
  155. spin_unlock(&pp->lock);
  156. }
  157. static void pp_pong(struct pp_ctx *pp)
  158. {
  159. u32 msg_data = -1, spad_data = -1;
  160. int pidx = 0;
  161. /* Read pong data */
  162. spad_data = ntb_spad_read(pp->ntb, 0);
  163. msg_data = ntb_msg_read(pp->ntb, &pidx, 0);
  164. ntb_msg_clear_sts(pp->ntb, -1);
  165. /*
  166. * Scratchpad and message data may differ, since message register can't
  167. * be rewritten unless status is cleared. Additionally either of them
  168. * might be unsupported
  169. */
  170. dev_dbg(&pp->ntb->dev, "Pong spad %#x, msg %#x (port %d)\n",
  171. spad_data, msg_data, ntb_peer_port_number(pp->ntb, pidx));
  172. atomic_inc(&pp->count);
  173. ntb_db_set_mask(pp->ntb, pp->in_db);
  174. ntb_db_clear(pp->ntb, pp->in_db);
  175. hrtimer_start(&pp->timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);
  176. }
  177. static enum hrtimer_restart pp_timer_func(struct hrtimer *t)
  178. {
  179. struct pp_ctx *pp = to_pp_timer(t);
  180. pp_ping(pp);
  181. return HRTIMER_NORESTART;
  182. }
  183. static void pp_link_event(void *ctx)
  184. {
  185. struct pp_ctx *pp = ctx;
  186. pp_setup(pp);
  187. }
  188. static void pp_db_event(void *ctx, int vec)
  189. {
  190. struct pp_ctx *pp = ctx;
  191. pp_pong(pp);
  192. }
  193. static const struct ntb_ctx_ops pp_ops = {
  194. .link_event = pp_link_event,
  195. .db_event = pp_db_event
  196. };
  197. static int pp_check_ntb(struct ntb_dev *ntb)
  198. {
  199. u64 pmask;
  200. if (ntb_db_is_unsafe(ntb)) {
  201. dev_dbg(&ntb->dev, "Doorbell is unsafe\n");
  202. if (!unsafe)
  203. return -EINVAL;
  204. }
  205. if (ntb_spad_is_unsafe(ntb)) {
  206. dev_dbg(&ntb->dev, "Scratchpad is unsafe\n");
  207. if (!unsafe)
  208. return -EINVAL;
  209. }
  210. pmask = GENMASK_ULL(ntb_peer_port_count(ntb), 0);
  211. if ((ntb_db_valid_mask(ntb) & pmask) != pmask) {
  212. dev_err(&ntb->dev, "Unsupported DB configuration\n");
  213. return -EINVAL;
  214. }
  215. if (ntb_spad_count(ntb) < 1 && ntb_msg_count(ntb) < 1) {
  216. dev_err(&ntb->dev, "Scratchpads and messages unsupported\n");
  217. return -EINVAL;
  218. } else if (ntb_spad_count(ntb) < 1) {
  219. dev_dbg(&ntb->dev, "Scratchpads unsupported\n");
  220. } else if (ntb_msg_count(ntb) < 1) {
  221. dev_dbg(&ntb->dev, "Messages unsupported\n");
  222. }
  223. return 0;
  224. }
  225. static struct pp_ctx *pp_create_data(struct ntb_dev *ntb)
  226. {
  227. struct pp_ctx *pp;
  228. pp = devm_kzalloc(&ntb->dev, sizeof(*pp), GFP_KERNEL);
  229. if (!pp)
  230. return ERR_PTR(-ENOMEM);
  231. pp->ntb = ntb;
  232. atomic_set(&pp->count, 0);
  233. spin_lock_init(&pp->lock);
  234. hrtimer_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  235. pp->timer.function = pp_timer_func;
  236. return pp;
  237. }
  238. static void pp_init_flds(struct pp_ctx *pp)
  239. {
  240. int pidx, lport, pcnt;
  241. /* Find global port index */
  242. lport = ntb_port_number(pp->ntb);
  243. pcnt = ntb_peer_port_count(pp->ntb);
  244. for (pidx = 0; pidx < pcnt; pidx++) {
  245. if (lport < ntb_peer_port_number(pp->ntb, pidx))
  246. break;
  247. }
  248. pp->in_db = BIT_ULL(lport);
  249. pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
  250. pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
  251. dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
  252. pp->in_db, pp->pmask, pp->nmask);
  253. }
  254. static int pp_mask_events(struct pp_ctx *pp)
  255. {
  256. u64 db_mask, msg_mask;
  257. int ret;
  258. db_mask = ntb_db_valid_mask(pp->ntb);
  259. ret = ntb_db_set_mask(pp->ntb, db_mask);
  260. if (ret)
  261. return ret;
  262. /* Skip message events masking if unsupported */
  263. if (ntb_msg_count(pp->ntb) < 1)
  264. return 0;
  265. msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
  266. return ntb_msg_set_mask(pp->ntb, msg_mask);
  267. }
  268. static int pp_setup_ctx(struct pp_ctx *pp)
  269. {
  270. int ret;
  271. ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
  272. if (ret)
  273. return ret;
  274. ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
  275. /* Might be not necessary */
  276. ntb_link_event(pp->ntb);
  277. return 0;
  278. }
  279. static void pp_clear_ctx(struct pp_ctx *pp)
  280. {
  281. ntb_link_disable(pp->ntb);
  282. ntb_clear_ctx(pp->ntb);
  283. }
  284. static void pp_setup_dbgfs(struct pp_ctx *pp)
  285. {
  286. struct pci_dev *pdev = pp->ntb->pdev;
  287. pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
  288. debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
  289. }
  290. static void pp_clear_dbgfs(struct pp_ctx *pp)
  291. {
  292. debugfs_remove_recursive(pp->dbgfs_dir);
  293. }
  294. static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
  295. {
  296. struct pp_ctx *pp;
  297. int ret;
  298. ret = pp_check_ntb(ntb);
  299. if (ret)
  300. return ret;
  301. pp = pp_create_data(ntb);
  302. if (IS_ERR(pp))
  303. return PTR_ERR(pp);
  304. pp_init_flds(pp);
  305. ret = pp_mask_events(pp);
  306. if (ret)
  307. return ret;
  308. ret = pp_setup_ctx(pp);
  309. if (ret)
  310. return ret;
  311. pp_setup_dbgfs(pp);
  312. return 0;
  313. }
  314. static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
  315. {
  316. struct pp_ctx *pp = ntb->ctx;
  317. pp_clear_dbgfs(pp);
  318. pp_clear_ctx(pp);
  319. pp_clear(pp);
  320. }
  321. static struct ntb_client pp_client = {
  322. .ops = {
  323. .probe = pp_probe,
  324. .remove = pp_remove
  325. }
  326. };
  327. static int __init pp_init(void)
  328. {
  329. int ret;
  330. if (debugfs_initialized())
  331. pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
  332. ret = ntb_register_client(&pp_client);
  333. if (ret)
  334. debugfs_remove_recursive(pp_dbgfs_topdir);
  335. return ret;
  336. }
  337. module_init(pp_init);
  338. static void __exit pp_exit(void)
  339. {
  340. ntb_unregister_client(&pp_client);
  341. debugfs_remove_recursive(pp_dbgfs_topdir);
  342. }
  343. module_exit(pp_exit);