1/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
2/*
3 * Copyright(c) 2015 - 2018 Intel Corporation.
4 */
5
6#ifndef _HFI1_IOWAIT_H
7#define _HFI1_IOWAIT_H
8
9#include <linux/list.h>
10#include <linux/workqueue.h>
11#include <linux/wait.h>
12#include <linux/sched.h>
13
14#include "sdma_txreq.h"
15
16/*
17 * typedef (*restart_t)() - restart callback
18 * @work: pointer to work structure
19 */
20typedef void (*restart_t)(struct work_struct *work);
21
22#define IOWAIT_PENDING_IB 0x0
23#define IOWAIT_PENDING_TID 0x1
24
25/*
26 * A QP can have multiple Send Engines (SEs).
27 *
28 * The current use case is for supporting a TID RDMA
29 * packet build/xmit mechanism independent from verbs.
30 */
31#define IOWAIT_SES 2
32#define IOWAIT_IB_SE 0
33#define IOWAIT_TID_SE 1
34
35struct sdma_txreq;
36struct sdma_engine;
37/**
38 * @iowork: the work struct
39 * @tx_head: list of prebuilt packets
40 * @iow: the parent iowait structure
41 *
42 * This structure is the work item (process) specific
43 * details associated with the each of the two SEs of the
44 * QP.
45 *
46 * The workstruct and the queued TXs are unique to each
47 * SE.
48 */
49struct iowait;
50struct iowait_work {
51 struct work_struct iowork;
52 struct list_head tx_head;
53 struct iowait *iow;
54};
55
56/**
57 * @list: used to add/insert into QP/PQ wait lists
58 * @tx_head: overflow list of sdma_txreq's
59 * @sleep: no space callback
60 * @wakeup: space callback wakeup
61 * @sdma_drained: sdma count drained
62 * @init_priority: callback to manipulate priority
63 * @lock: lock protected head of wait queue
64 * @iowork: workqueue overhead
65 * @wait_dma: wait for sdma_busy == 0
66 * @wait_pio: wait for pio_busy == 0
67 * @sdma_busy: # of packets in flight
68 * @count: total number of descriptors in tx_head'ed list
69 * @tx_limit: limit for overflow queuing
70 * @tx_count: number of tx entry's in tx_head'ed list
71 * @flags: wait flags (one per QP)
72 * @wait: SE array for multiple legs
73 *
74 * This is to be embedded in user's state structure
75 * (QP or PQ).
76 *
77 * The sleep and wakeup members are a
78 * bit misnamed. They do not strictly
79 * speaking sleep or wake up, but they
80 * are callbacks for the ULP to implement
81 * what ever queuing/dequeuing of
82 * the embedded iowait and its containing struct
83 * when a resource shortage like SDMA ring space
84 * or PIO credit space is seen.
85 *
86 * Both potentially have locks help
87 * so sleeping is not allowed and it is not
88 * supported to submit txreqs from the wakeup
89 * call directly because of lock conflicts.
90 *
91 * The wait_dma member along with the iow
92 *
93 * The lock field is used by waiters to record
94 * the seqlock_t that guards the list head.
95 * Waiters explicitly know that, but the destroy
96 * code that unwaits QPs does not.
97 */
98struct iowait {
99 struct list_head list;
100 int (*sleep)(
101 struct sdma_engine *sde,
102 struct iowait_work *wait,
103 struct sdma_txreq *tx,
104 uint seq,
105 bool pkts_sent
106 );
107 void (*wakeup)(struct iowait *wait, int reason);
108 void (*sdma_drained)(struct iowait *wait);
109 void (*init_priority)(struct iowait *wait);
110 seqlock_t *lock;
111 wait_queue_head_t wait_dma;
112 wait_queue_head_t wait_pio;
113 atomic_t sdma_busy;
114 atomic_t pio_busy;
115 u32 count;
116 u32 tx_limit;
117 u32 tx_count;
118 u8 starved_cnt;
119 u8 priority;
120 unsigned long flags;
121 struct iowait_work wait[IOWAIT_SES];
122};
123
124#define SDMA_AVAIL_REASON 0
125
126void iowait_set_flag(struct iowait *wait, u32 flag);
127bool iowait_flag_set(struct iowait *wait, u32 flag);
128void iowait_clear_flag(struct iowait *wait, u32 flag);
129
130void iowait_init(struct iowait *wait, u32 tx_limit,
131 void (*func)(struct work_struct *work),
132 void (*tidfunc)(struct work_struct *work),
133 int (*sleep)(struct sdma_engine *sde,
134 struct iowait_work *wait,
135 struct sdma_txreq *tx,
136 uint seq,
137 bool pkts_sent),
138 void (*wakeup)(struct iowait *wait, int reason),
139 void (*sdma_drained)(struct iowait *wait),
140 void (*init_priority)(struct iowait *wait));
141
142/**
143 * iowait_schedule() - schedule the default send engine work
144 * @wait: wait struct to schedule
145 * @wq: workqueue for schedule
146 * @cpu: cpu
147 */
148static inline bool iowait_schedule(struct iowait *wait,
149 struct workqueue_struct *wq, int cpu)
150{
151 return !!queue_work_on(cpu, wq, work: &wait->wait[IOWAIT_IB_SE].iowork);
152}
153
154/**
155 * iowait_tid_schedule - schedule the tid SE
156 * @wait: the iowait structure
157 * @wq: the work queue
158 * @cpu: the cpu
159 */
160static inline bool iowait_tid_schedule(struct iowait *wait,
161 struct workqueue_struct *wq, int cpu)
162{
163 return !!queue_work_on(cpu, wq, work: &wait->wait[IOWAIT_TID_SE].iowork);
164}
165
166/**
167 * iowait_sdma_drain() - wait for DMAs to drain
168 *
169 * @wait: iowait structure
170 *
171 * This will delay until the iowait sdmas have
172 * completed.
173 */
174static inline void iowait_sdma_drain(struct iowait *wait)
175{
176 wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
177}
178
179/**
180 * iowait_sdma_pending() - return sdma pending count
181 *
182 * @wait: iowait structure
183 *
184 */
185static inline int iowait_sdma_pending(struct iowait *wait)
186{
187 return atomic_read(v: &wait->sdma_busy);
188}
189
190/**
191 * iowait_sdma_inc - note sdma io pending
192 * @wait: iowait structure
193 */
194static inline void iowait_sdma_inc(struct iowait *wait)
195{
196 atomic_inc(v: &wait->sdma_busy);
197}
198
199/**
200 * iowait_sdma_add - add count to pending
201 * @wait: iowait structure
202 */
203static inline void iowait_sdma_add(struct iowait *wait, int count)
204{
205 atomic_add(i: count, v: &wait->sdma_busy);
206}
207
208/**
209 * iowait_sdma_dec - note sdma complete
210 * @wait: iowait structure
211 */
212static inline int iowait_sdma_dec(struct iowait *wait)
213{
214 if (!wait)
215 return 0;
216 return atomic_dec_and_test(v: &wait->sdma_busy);
217}
218
219/**
220 * iowait_pio_drain() - wait for pios to drain
221 *
222 * @wait: iowait structure
223 *
224 * This will delay until the iowait pios have
225 * completed.
226 */
227static inline void iowait_pio_drain(struct iowait *wait)
228{
229 wait_event_timeout(wait->wait_pio,
230 !atomic_read(&wait->pio_busy),
231 HZ);
232}
233
234/**
235 * iowait_pio_pending() - return pio pending count
236 *
237 * @wait: iowait structure
238 *
239 */
240static inline int iowait_pio_pending(struct iowait *wait)
241{
242 return atomic_read(v: &wait->pio_busy);
243}
244
245/**
246 * iowait_pio_inc - note pio pending
247 * @wait: iowait structure
248 */
249static inline void iowait_pio_inc(struct iowait *wait)
250{
251 atomic_inc(v: &wait->pio_busy);
252}
253
254/**
255 * iowait_pio_dec - note pio complete
256 * @wait: iowait structure
257 */
258static inline int iowait_pio_dec(struct iowait *wait)
259{
260 if (!wait)
261 return 0;
262 return atomic_dec_and_test(v: &wait->pio_busy);
263}
264
265/**
266 * iowait_drain_wakeup() - trigger iowait_drain() waiter
267 *
268 * @wait: iowait structure
269 *
270 * This will trigger any waiters.
271 */
272static inline void iowait_drain_wakeup(struct iowait *wait)
273{
274 wake_up(&wait->wait_dma);
275 wake_up(&wait->wait_pio);
276 if (wait->sdma_drained)
277 wait->sdma_drained(wait);
278}
279
280/**
281 * iowait_get_txhead() - get packet off of iowait list
282 *
283 * @wait: iowait_work structure
284 */
285static inline struct sdma_txreq *iowait_get_txhead(struct iowait_work *wait)
286{
287 struct sdma_txreq *tx = NULL;
288
289 if (!list_empty(head: &wait->tx_head)) {
290 tx = list_first_entry(
291 &wait->tx_head,
292 struct sdma_txreq,
293 list);
294 list_del_init(entry: &tx->list);
295 }
296 return tx;
297}
298
299static inline u16 iowait_get_desc(struct iowait_work *w)
300{
301 u16 num_desc = 0;
302 struct sdma_txreq *tx = NULL;
303
304 if (!list_empty(head: &w->tx_head)) {
305 tx = list_first_entry(&w->tx_head, struct sdma_txreq,
306 list);
307 num_desc = tx->num_desc;
308 if (tx->flags & SDMA_TXREQ_F_VIP)
309 w->iow->priority++;
310 }
311 return num_desc;
312}
313
314static inline u32 iowait_get_all_desc(struct iowait *w)
315{
316 u32 num_desc = 0;
317
318 num_desc = iowait_get_desc(w: &w->wait[IOWAIT_IB_SE]);
319 num_desc += iowait_get_desc(w: &w->wait[IOWAIT_TID_SE]);
320 return num_desc;
321}
322
323static inline void iowait_update_priority(struct iowait_work *w)
324{
325 struct sdma_txreq *tx = NULL;
326
327 if (!list_empty(head: &w->tx_head)) {
328 tx = list_first_entry(&w->tx_head, struct sdma_txreq,
329 list);
330 if (tx->flags & SDMA_TXREQ_F_VIP)
331 w->iow->priority++;
332 }
333}
334
335static inline void iowait_update_all_priority(struct iowait *w)
336{
337 iowait_update_priority(w: &w->wait[IOWAIT_IB_SE]);
338 iowait_update_priority(w: &w->wait[IOWAIT_TID_SE]);
339}
340
341static inline void iowait_init_priority(struct iowait *w)
342{
343 w->priority = 0;
344 if (w->init_priority)
345 w->init_priority(w);
346}
347
348static inline void iowait_get_priority(struct iowait *w)
349{
350 iowait_init_priority(w);
351 iowait_update_all_priority(w);
352}
353
354/**
355 * iowait_queue - Put the iowait on a wait queue
356 * @pkts_sent: have some packets been sent before queuing?
357 * @w: the iowait struct
358 * @wait_head: the wait queue
359 *
360 * This function is called to insert an iowait struct into a
361 * wait queue after a resource (eg, sdma descriptor or pio
362 * buffer) is run out.
363 */
364static inline void iowait_queue(bool pkts_sent, struct iowait *w,
365 struct list_head *wait_head)
366{
367 /*
368 * To play fair, insert the iowait at the tail of the wait queue if it
369 * has already sent some packets; Otherwise, put it at the head.
370 * However, if it has priority packets to send, also put it at the
371 * head.
372 */
373 if (pkts_sent)
374 w->starved_cnt = 0;
375 else
376 w->starved_cnt++;
377
378 if (w->priority > 0 || !pkts_sent)
379 list_add(new: &w->list, head: wait_head);
380 else
381 list_add_tail(new: &w->list, head: wait_head);
382}
383
384/**
385 * iowait_starve_clear - clear the wait queue's starve count
386 * @pkts_sent: have some packets been sent?
387 * @w: the iowait struct
388 *
389 * This function is called to clear the starve count. If no
390 * packets have been sent, the starve count will not be cleared.
391 */
392static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
393{
394 if (pkts_sent)
395 w->starved_cnt = 0;
396}
397
398/* Update the top priority index */
399uint iowait_priority_update_top(struct iowait *w,
400 struct iowait *top,
401 uint idx, uint top_idx);
402
403/**
404 * iowait_packet_queued() - determine if a packet is queued
405 * @wait: the iowait_work structure
406 */
407static inline bool iowait_packet_queued(struct iowait_work *wait)
408{
409 return !list_empty(head: &wait->tx_head);
410}
411
412/**
413 * inc_wait_count - increment wait counts
414 * @w: the log work struct
415 * @n: the count
416 */
417static inline void iowait_inc_wait_count(struct iowait_work *w, u16 n)
418{
419 if (!w)
420 return;
421 w->iow->tx_count++;
422 w->iow->count += n;
423}
424
425/**
426 * iowait_get_tid_work - return iowait_work for tid SE
427 * @w: the iowait struct
428 */
429static inline struct iowait_work *iowait_get_tid_work(struct iowait *w)
430{
431 return &w->wait[IOWAIT_TID_SE];
432}
433
434/**
435 * iowait_get_ib_work - return iowait_work for ib SE
436 * @w: the iowait struct
437 */
438static inline struct iowait_work *iowait_get_ib_work(struct iowait *w)
439{
440 return &w->wait[IOWAIT_IB_SE];
441}
442
443/**
444 * iowait_ioww_to_iow - return iowait given iowait_work
445 * @w: the iowait_work struct
446 */
447static inline struct iowait *iowait_ioww_to_iow(struct iowait_work *w)
448{
449 if (likely(w))
450 return w->iow;
451 return NULL;
452}
453
454void iowait_cancel_work(struct iowait *w);
455int iowait_set_work_flag(struct iowait_work *w);
456
457#endif
458

source code of linux/drivers/infiniband/hw/hfi1/iowait.h