drivers/infiniband/hw/hfi1/iowait.h

   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