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
pp_find_next_peer(struct pp_ctx * pp)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
pp_setup(struct pp_ctx * pp)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
pp_clear(struct pp_ctx * pp)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
pp_ping(struct pp_ctx * pp)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
pp_pong(struct pp_ctx * pp)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
pp_timer_func(struct hrtimer * t)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
pp_link_event(void * ctx)223 static void pp_link_event(void *ctx)
224 {
225 struct pp_ctx *pp = ctx;
226
227 pp_setup(pp);
228 }
229
pp_db_event(void * ctx,int vec)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
pp_check_ntb(struct ntb_dev * ntb)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
pp_create_data(struct ntb_dev * ntb)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_setup(&pp->timer, pp_timer_func, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
288
289 return pp;
290 }
291
pp_init_flds(struct pp_ctx * pp)292 static void pp_init_flds(struct pp_ctx *pp)
293 {
294 int pidx, lport, pcnt;
295
296 /* Find global port index */
297 lport = ntb_port_number(pp->ntb);
298 pcnt = ntb_peer_port_count(pp->ntb);
299 for (pidx = 0; pidx < pcnt; pidx++) {
300 if (lport < ntb_peer_port_number(pp->ntb, pidx))
301 break;
302 }
303
304 pp->in_db = BIT_ULL(lport);
305 pp->pmask = GENMASK_ULL(pidx, 0) >> 1;
306 pp->nmask = GENMASK_ULL(pcnt - 1, pidx);
307
308 dev_dbg(&pp->ntb->dev, "Inbound db %#llx, prev %#llx, next %#llx\n",
309 pp->in_db, pp->pmask, pp->nmask);
310 }
311
pp_mask_events(struct pp_ctx * pp)312 static int pp_mask_events(struct pp_ctx *pp)
313 {
314 u64 db_mask, msg_mask;
315 int ret;
316
317 db_mask = ntb_db_valid_mask(pp->ntb);
318 ret = ntb_db_set_mask(pp->ntb, db_mask);
319 if (ret)
320 return ret;
321
322 /* Skip message events masking if unsupported */
323 if (ntb_msg_count(pp->ntb) < 1)
324 return 0;
325
326 msg_mask = ntb_msg_outbits(pp->ntb) | ntb_msg_inbits(pp->ntb);
327 return ntb_msg_set_mask(pp->ntb, msg_mask);
328 }
329
pp_setup_ctx(struct pp_ctx * pp)330 static int pp_setup_ctx(struct pp_ctx *pp)
331 {
332 int ret;
333
334 ret = ntb_set_ctx(pp->ntb, pp, &pp_ops);
335 if (ret)
336 return ret;
337
338 ntb_link_enable(pp->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
339 /* Might be not necessary */
340 ntb_link_event(pp->ntb);
341
342 return 0;
343 }
344
pp_clear_ctx(struct pp_ctx * pp)345 static void pp_clear_ctx(struct pp_ctx *pp)
346 {
347 ntb_link_disable(pp->ntb);
348
349 ntb_clear_ctx(pp->ntb);
350 }
351
pp_setup_dbgfs(struct pp_ctx * pp)352 static void pp_setup_dbgfs(struct pp_ctx *pp)
353 {
354 struct pci_dev *pdev = pp->ntb->pdev;
355
356 pp->dbgfs_dir = debugfs_create_dir(pci_name(pdev), pp_dbgfs_topdir);
357
358 debugfs_create_atomic_t("count", 0600, pp->dbgfs_dir, &pp->count);
359 }
360
pp_clear_dbgfs(struct pp_ctx * pp)361 static void pp_clear_dbgfs(struct pp_ctx *pp)
362 {
363 debugfs_remove_recursive(pp->dbgfs_dir);
364 }
365
pp_probe(struct ntb_client * client,struct ntb_dev * ntb)366 static int pp_probe(struct ntb_client *client, struct ntb_dev *ntb)
367 {
368 struct pp_ctx *pp;
369 int ret;
370
371 ret = pp_check_ntb(ntb);
372 if (ret)
373 return ret;
374
375 pp = pp_create_data(ntb);
376 if (IS_ERR(pp))
377 return PTR_ERR(pp);
378
379 pp_init_flds(pp);
380
381 ret = pp_mask_events(pp);
382 if (ret)
383 return ret;
384
385 ret = pp_setup_ctx(pp);
386 if (ret)
387 return ret;
388
389 pp_setup_dbgfs(pp);
390
391 return 0;
392 }
393
pp_remove(struct ntb_client * client,struct ntb_dev * ntb)394 static void pp_remove(struct ntb_client *client, struct ntb_dev *ntb)
395 {
396 struct pp_ctx *pp = ntb->ctx;
397
398 pp_clear_dbgfs(pp);
399
400 pp_clear_ctx(pp);
401
402 pp_clear(pp);
403 }
404
405 static struct ntb_client pp_client = {
406 .ops = {
407 .probe = pp_probe,
408 .remove = pp_remove
409 }
410 };
411
pp_init(void)412 static int __init pp_init(void)
413 {
414 int ret;
415
416 if (debugfs_initialized())
417 pp_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME, NULL);
418
419 ret = ntb_register_client(&pp_client);
420 if (ret)
421 debugfs_remove_recursive(pp_dbgfs_topdir);
422
423 return ret;
424 }
425 module_init(pp_init);
426
pp_exit(void)427 static void __exit pp_exit(void)
428 {
429 ntb_unregister_client(&pp_client);
430 debugfs_remove_recursive(pp_dbgfs_topdir);
431 }
432 module_exit(pp_exit);
433