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_init(&pp->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
288 pp->timer.function = pp_timer_func;
289
290 return pp;
291 }
292
pp_init_flds(struct pp_ctx * pp)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
pp_mask_events(struct pp_ctx * pp)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
pp_setup_ctx(struct pp_ctx * pp)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
pp_clear_ctx(struct pp_ctx * pp)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
pp_setup_dbgfs(struct pp_ctx * pp)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
pp_clear_dbgfs(struct pp_ctx * pp)362 static void pp_clear_dbgfs(struct pp_ctx *pp)
363 {
364 debugfs_remove_recursive(pp->dbgfs_dir);
365 }
366
pp_probe(struct ntb_client * client,struct ntb_dev * ntb)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
pp_remove(struct ntb_client * client,struct ntb_dev * ntb)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
pp_init(void)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
pp_exit(void)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);
434
