1 #ifndef _HFI1_IOWAIT_H
2 #define _HFI1_IOWAIT_H
3 /*
4 * Copyright(c) 2015 - 2018 Intel Corporation.
5 *
6 * This file is provided under a dual BSD/GPLv2 license. When using or
7 * redistributing this file, you may do so under either license.
8 *
9 * GPL LICENSE SUMMARY
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of version 2 of the GNU General Public License as
13 * published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * BSD LICENSE
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 copyright
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 */
49
50 #include <linux/list.h>
51 #include <linux/workqueue.h>
52 #include <linux/wait.h>
53 #include <linux/sched.h>
54
55 #include "sdma_txreq.h"
56
57 /*
58 * typedef (*restart_t)() - restart callback
59 * @work: pointer to work structure
60 */
61 typedef void (*restart_t)(struct work_struct *work);
62
63 #define IOWAIT_PENDING_IB 0x0
64 #define IOWAIT_PENDING_TID 0x1
65
66 /*
67 * A QP can have multiple Send Engines (SEs).
68 *
69 * The current use case is for supporting a TID RDMA
70 * packet build/xmit mechanism independent from verbs.
71 */
72 #define IOWAIT_SES 2
73 #define IOWAIT_IB_SE 0
74 #define IOWAIT_TID_SE 1
75
76 struct sdma_txreq;
77 struct sdma_engine;
78 /**
79 * @iowork: the work struct
80 * @tx_head: list of prebuilt packets
81 * @iow: the parent iowait structure
82 *
83 * This structure is the work item (process) specific
84 * details associated with the each of the two SEs of the
85 * QP.
86 *
87 * The workstruct and the queued TXs are unique to each
88 * SE.
89 */
90 struct iowait;
91 struct iowait_work {
92 struct work_struct iowork;
93 struct list_head tx_head;
94 struct iowait *iow;
95 };
96
97 /**
98 * @list: used to add/insert into QP/PQ wait lists
99 * @tx_head: overflow list of sdma_txreq's
100 * @sleep: no space callback
101 * @wakeup: space callback wakeup
102 * @sdma_drained: sdma count drained
103 * @init_priority: callback to manipulate priority
104 * @lock: lock protected head of wait queue
105 * @iowork: workqueue overhead
106 * @wait_dma: wait for sdma_busy == 0
107 * @wait_pio: wait for pio_busy == 0
108 * @sdma_busy: # of packets in flight
109 * @count: total number of descriptors in tx_head'ed list
110 * @tx_limit: limit for overflow queuing
111 * @tx_count: number of tx entry's in tx_head'ed list
112 * @flags: wait flags (one per QP)
113 * @wait: SE array for multiple legs
114 *
115 * This is to be embedded in user's state structure
116 * (QP or PQ).
117 *
118 * The sleep and wakeup members are a
119 * bit misnamed. They do not strictly
120 * speaking sleep or wake up, but they
121 * are callbacks for the ULP to implement
122 * what ever queuing/dequeuing of
123 * the embedded iowait and its containing struct
124 * when a resource shortage like SDMA ring space
125 * or PIO credit space is seen.
126 *
127 * Both potentially have locks help
128 * so sleeping is not allowed and it is not
129 * supported to submit txreqs from the wakeup
130 * call directly because of lock conflicts.
131 *
132 * The wait_dma member along with the iow
133 *
134 * The lock field is used by waiters to record
135 * the seqlock_t that guards the list head.
136 * Waiters explicity know that, but the destroy
137 * code that unwaits QPs does not.
138 */
139 struct iowait {
140 struct list_head list;
141 int (*sleep)(
142 struct sdma_engine *sde,
143 struct iowait_work *wait,
144 struct sdma_txreq *tx,
145 uint seq,
146 bool pkts_sent
147 );
148 void (*wakeup)(struct iowait *wait, int reason);
149 void (*sdma_drained)(struct iowait *wait);
150 void (*init_priority)(struct iowait *wait);
151 seqlock_t *lock;
152 wait_queue_head_t wait_dma;
153 wait_queue_head_t wait_pio;
154 atomic_t sdma_busy;
155 atomic_t pio_busy;
156 u32 count;
157 u32 tx_limit;
158 u32 tx_count;
159 u8 starved_cnt;
160 u8 priority;
161 unsigned long flags;
162 struct iowait_work wait[IOWAIT_SES];
163 };
164
165 #define SDMA_AVAIL_REASON 0
166
167 void iowait_set_flag(struct iowait *wait, u32 flag);
168 bool iowait_flag_set(struct iowait *wait, u32 flag);
169 void iowait_clear_flag(struct iowait *wait, u32 flag);
170
171 void iowait_init(struct iowait *wait, u32 tx_limit,
172 void (*func)(struct work_struct *work),
173 void (*tidfunc)(struct work_struct *work),
174 int (*sleep)(struct sdma_engine *sde,
175 struct iowait_work *wait,
176 struct sdma_txreq *tx,
177 uint seq,
178 bool pkts_sent),
179 void (*wakeup)(struct iowait *wait, int reason),
180 void (*sdma_drained)(struct iowait *wait),
181 void (*init_priority)(struct iowait *wait));
182
183 /**
184 * iowait_schedule() - schedule the default send engine work
185 * @wait: wait struct to schedule
186 * @wq: workqueue for schedule
187 * @cpu: cpu
188 */
189 static inline bool iowait_schedule(struct iowait *wait,
190 struct workqueue_struct *wq, int cpu)
191 {
192 return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_IB_SE].iowork);
193 }
194
195 /**
196 * iowait_tid_schedule - schedule the tid SE
197 * @wait: the iowait structure
198 * @wq: the work queue
199 * @cpu: the cpu
200 */
201 static inline bool iowait_tid_schedule(struct iowait *wait,
202 struct workqueue_struct *wq, int cpu)
203 {
204 return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_TID_SE].iowork);
205 }
206
207 /**
208 * iowait_sdma_drain() - wait for DMAs to drain
209 *
210 * @wait: iowait structure
211 *
212 * This will delay until the iowait sdmas have
213 * completed.
214 */
215 static inline void iowait_sdma_drain(struct iowait *wait)
216 {
217 wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
218 }
219
220 /**
221 * iowait_sdma_pending() - return sdma pending count
222 *
223 * @wait: iowait structure
224 *
225 */
226 static inline int iowait_sdma_pending(struct iowait *wait)
227 {
228 return atomic_read(&wait->sdma_busy);
229 }
230
231 /**
232 * iowait_sdma_inc - note sdma io pending
233 * @wait: iowait structure
234 */
235 static inline void iowait_sdma_inc(struct iowait *wait)
236 {
237 atomic_inc(&wait->sdma_busy);
238 }
239
240 /**
241 * iowait_sdma_add - add count to pending
242 * @wait: iowait structure
243 */
244 static inline void iowait_sdma_add(struct iowait *wait, int count)
245 {
246 atomic_add(count, &wait->sdma_busy);
247 }
248
249 /**
250 * iowait_sdma_dec - note sdma complete
251 * @wait: iowait structure
252 */
253 static inline int iowait_sdma_dec(struct iowait *wait)
254 {
255 if (!wait)
256 return 0;
257 return atomic_dec_and_test(&wait->sdma_busy);
258 }
259
260 /**
261 * iowait_pio_drain() - wait for pios to drain
262 *
263 * @wait: iowait structure
264 *
265 * This will delay until the iowait pios have
266 * completed.
267 */
268 static inline void iowait_pio_drain(struct iowait *wait)
269 {
270 wait_event_timeout(wait->wait_pio,
271 !atomic_read(&wait->pio_busy),
272 HZ);
273 }
274
275 /**
276 * iowait_pio_pending() - return pio pending count
277 *
278 * @wait: iowait structure
279 *
280 */
281 static inline int iowait_pio_pending(struct iowait *wait)
282 {
283 return atomic_read(&wait->pio_busy);
284 }
285
286 /**
287 * iowait_pio_inc - note pio pending
288 * @wait: iowait structure
289 */
290 static inline void iowait_pio_inc(struct iowait *wait)
291 {
292 atomic_inc(&wait->pio_busy);
293 }
294
295 /**
296 * iowait_pio_dec - note pio complete
297 * @wait: iowait structure
298 */
299 static inline int iowait_pio_dec(struct iowait *wait)
300 {
301 if (!wait)
302 return 0;
303 return atomic_dec_and_test(&wait->pio_busy);
304 }
305
306 /**
307 * iowait_drain_wakeup() - trigger iowait_drain() waiter
308 *
309 * @wait: iowait structure
310 *
311 * This will trigger any waiters.
312 */
313 static inline void iowait_drain_wakeup(struct iowait *wait)
314 {
315 wake_up(&wait->wait_dma);
316 wake_up(&wait->wait_pio);
317 if (wait->sdma_drained)
318 wait->sdma_drained(wait);
319 }
320
321 /**
322 * iowait_get_txhead() - get packet off of iowait list
323 *
324 * @wait iowait_work struture
325 */
326 static inline struct sdma_txreq *iowait_get_txhead(struct iowait_work *wait)
327 {
328 struct sdma_txreq *tx = NULL;
329
330 if (!list_empty(&wait->tx_head)) {
331 tx = list_first_entry(
332 &wait->tx_head,
333 struct sdma_txreq,
334 list);
335 list_del_init(&tx->list);
336 }
337 return tx;
338 }
339
340 static inline u16 iowait_get_desc(struct iowait_work *w)
341 {
342 u16 num_desc = 0;
343 struct sdma_txreq *tx = NULL;
344
345 if (!list_empty(&w->tx_head)) {
346 tx = list_first_entry(&w->tx_head, struct sdma_txreq,
347 list);
348 num_desc = tx->num_desc;
349 if (tx->flags & SDMA_TXREQ_F_VIP)
350 w->iow->priority++;
351 }
352 return num_desc;
353 }
354
355 static inline u32 iowait_get_all_desc(struct iowait *w)
356 {
357 u32 num_desc = 0;
358
359 num_desc = iowait_get_desc(&w->wait[IOWAIT_IB_SE]);
360 num_desc += iowait_get_desc(&w->wait[IOWAIT_TID_SE]);
361 return num_desc;
362 }
363
364 static inline void iowait_update_priority(struct iowait_work *w)
365 {
366 struct sdma_txreq *tx = NULL;
367
368 if (!list_empty(&w->tx_head)) {
369 tx = list_first_entry(&w->tx_head, struct sdma_txreq,
370 list);
371 if (tx->flags & SDMA_TXREQ_F_VIP)
372 w->iow->priority++;
373 }
374 }
375
376 static inline void iowait_update_all_priority(struct iowait *w)
377 {
378 iowait_update_priority(&w->wait[IOWAIT_IB_SE]);
379 iowait_update_priority(&w->wait[IOWAIT_TID_SE]);
380 }
381
382 static inline void iowait_init_priority(struct iowait *w)
383 {
384 w->priority = 0;
385 if (w->init_priority)
386 w->init_priority(w);
387 }
388
389 static inline void iowait_get_priority(struct iowait *w)
390 {
391 iowait_init_priority(w);
392 iowait_update_all_priority(w);
393 }
394
395 /**
396 * iowait_queue - Put the iowait on a wait queue
397 * @pkts_sent: have some packets been sent before queuing?
398 * @w: the iowait struct
399 * @wait_head: the wait queue
400 *
401 * This function is called to insert an iowait struct into a
402 * wait queue after a resource (eg, sdma decriptor or pio
403 * buffer) is run out.
404 */
405 static inline void iowait_queue(bool pkts_sent, struct iowait *w,
406 struct list_head *wait_head)
407 {
408 /*
409 * To play fair, insert the iowait at the tail of the wait queue if it
410 * has already sent some packets; Otherwise, put it at the head.
411 * However, if it has priority packets to send, also put it at the
412 * head.
413 */
414 if (pkts_sent)
415 w->starved_cnt = 0;
416 else
417 w->starved_cnt++;
418
419 if (w->priority > 0 || !pkts_sent)
420 list_add(&w->list, wait_head);
421 else
422 list_add_tail(&w->list, wait_head);
423 }
424
425 /**
426 * iowait_starve_clear - clear the wait queue's starve count
427 * @pkts_sent: have some packets been sent?
428 * @w: the iowait struct
429 *
430 * This function is called to clear the starve count. If no
431 * packets have been sent, the starve count will not be cleared.
432 */
433 static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
434 {
435 if (pkts_sent)
436 w->starved_cnt = 0;
437 }
438
439 /* Update the top priority index */
440 uint iowait_priority_update_top(struct iowait *w,
441 struct iowait *top,
442 uint idx, uint top_idx);
443
444 /**
445 * iowait_packet_queued() - determine if a packet is queued
446 * @wait: the iowait_work structure
447 */
448 static inline bool iowait_packet_queued(struct iowait_work *wait)
449 {
450 return !list_empty(&wait->tx_head);
451 }
452
453 /**
454 * inc_wait_count - increment wait counts
455 * @w: the log work struct
456 * @n: the count
457 */
458 static inline void iowait_inc_wait_count(struct iowait_work *w, u16 n)
459 {
460 if (!w)
461 return;
462 w->iow->tx_count++;
463 w->iow->count += n;
464 }
465
466 /**
467 * iowait_get_tid_work - return iowait_work for tid SE
468 * @w: the iowait struct
469 */
470 static inline struct iowait_work *iowait_get_tid_work(struct iowait *w)
471 {
472 return &w->wait[IOWAIT_TID_SE];
473 }
474
475 /**
476 * iowait_get_ib_work - return iowait_work for ib SE
477 * @w: the iowait struct
478 */
479 static inline struct iowait_work *iowait_get_ib_work(struct iowait *w)
480 {
481 return &w->wait[IOWAIT_IB_SE];
482 }
483
484 /**
485 * iowait_ioww_to_iow - return iowait given iowait_work
486 * @w: the iowait_work struct
487 */
488 static inline struct iowait *iowait_ioww_to_iow(struct iowait_work *w)
489 {
490 if (likely(w))
491 return w->iow;
492 return NULL;
493 }
494
495 void iowait_cancel_work(struct iowait *w);
496 int iowait_set_work_flag(struct iowait_work *w);
497
498 #endif