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 */
20 typedef 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
35 struct sdma_txreq;
36 struct 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 */
49 struct iowait;
50 struct 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 explicity know that, but the destroy
96 * code that unwaits QPs does not.
97 */
98 struct 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
126 void iowait_set_flag(struct iowait *wait, u32 flag);
127 bool iowait_flag_set(struct iowait *wait, u32 flag);
128 void iowait_clear_flag(struct iowait *wait, u32 flag);
129
130 void 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 */
iowait_schedule(struct iowait * wait,struct workqueue_struct * wq,int cpu)148 static inline bool iowait_schedule(struct iowait *wait,
149 struct workqueue_struct *wq, int cpu)
150 {
151 return !!queue_work_on(cpu, wq, &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 */
iowait_tid_schedule(struct iowait * wait,struct workqueue_struct * wq,int cpu)160 static inline bool iowait_tid_schedule(struct iowait *wait,
161 struct workqueue_struct *wq, int cpu)
162 {
163 return !!queue_work_on(cpu, wq, &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 */
iowait_sdma_drain(struct iowait * wait)174 static 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 */
iowait_sdma_pending(struct iowait * wait)185 static inline int iowait_sdma_pending(struct iowait *wait)
186 {
187 return atomic_read(&wait->sdma_busy);
188 }
189
190 /**
191 * iowait_sdma_inc - note sdma io pending
192 * @wait: iowait structure
193 */
iowait_sdma_inc(struct iowait * wait)194 static inline void iowait_sdma_inc(struct iowait *wait)
195 {
196 atomic_inc(&wait->sdma_busy);
197 }
198
199 /**
200 * iowait_sdma_add - add count to pending
201 * @wait: iowait structure
202 */
iowait_sdma_add(struct iowait * wait,int count)203 static inline void iowait_sdma_add(struct iowait *wait, int count)
204 {
205 atomic_add(count, &wait->sdma_busy);
206 }
207
208 /**
209 * iowait_sdma_dec - note sdma complete
210 * @wait: iowait structure
211 */
iowait_sdma_dec(struct iowait * wait)212 static inline int iowait_sdma_dec(struct iowait *wait)
213 {
214 if (!wait)
215 return 0;
216 return atomic_dec_and_test(&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 */
iowait_pio_drain(struct iowait * wait)227 static 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 */
iowait_pio_pending(struct iowait * wait)240 static inline int iowait_pio_pending(struct iowait *wait)
241 {
242 return atomic_read(&wait->pio_busy);
243 }
244
245 /**
246 * iowait_pio_inc - note pio pending
247 * @wait: iowait structure
248 */
iowait_pio_inc(struct iowait * wait)249 static inline void iowait_pio_inc(struct iowait *wait)
250 {
251 atomic_inc(&wait->pio_busy);
252 }
253
254 /**
255 * iowait_pio_dec - note pio complete
256 * @wait: iowait structure
257 */
iowait_pio_dec(struct iowait * wait)258 static inline int iowait_pio_dec(struct iowait *wait)
259 {
260 if (!wait)
261 return 0;
262 return atomic_dec_and_test(&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 */
iowait_drain_wakeup(struct iowait * wait)272 static 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 */
iowait_get_txhead(struct iowait_work * wait)285 static inline struct sdma_txreq *iowait_get_txhead(struct iowait_work *wait)
286 {
287 struct sdma_txreq *tx = NULL;
288
289 if (!list_empty(&wait->tx_head)) {
290 tx = list_first_entry(
291 &wait->tx_head,
292 struct sdma_txreq,
293 list);
294 list_del_init(&tx->list);
295 }
296 return tx;
297 }
298
iowait_get_desc(struct iowait_work * w)299 static 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(&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
iowait_get_all_desc(struct iowait * w)314 static inline u32 iowait_get_all_desc(struct iowait *w)
315 {
316 u32 num_desc = 0;
317
318 num_desc = iowait_get_desc(&w->wait[IOWAIT_IB_SE]);
319 num_desc += iowait_get_desc(&w->wait[IOWAIT_TID_SE]);
320 return num_desc;
321 }
322
iowait_update_priority(struct iowait_work * w)323 static inline void iowait_update_priority(struct iowait_work *w)
324 {
325 struct sdma_txreq *tx = NULL;
326
327 if (!list_empty(&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
iowait_update_all_priority(struct iowait * w)335 static inline void iowait_update_all_priority(struct iowait *w)
336 {
337 iowait_update_priority(&w->wait[IOWAIT_IB_SE]);
338 iowait_update_priority(&w->wait[IOWAIT_TID_SE]);
339 }
340
iowait_init_priority(struct iowait * w)341 static 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
iowait_get_priority(struct iowait * w)348 static 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 */
iowait_queue(bool pkts_sent,struct iowait * w,struct list_head * wait_head)364 static 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(&w->list, wait_head);
380 else
381 list_add_tail(&w->list, 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 */
iowait_starve_clear(bool pkts_sent,struct iowait * w)392 static 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 */
399 uint 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 */
iowait_packet_queued(struct iowait_work * wait)407 static inline bool iowait_packet_queued(struct iowait_work *wait)
408 {
409 return !list_empty(&wait->tx_head);
410 }
411
412 /**
413 * inc_wait_count - increment wait counts
414 * @w: the log work struct
415 * @n: the count
416 */
iowait_inc_wait_count(struct iowait_work * w,u16 n)417 static 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 */
iowait_get_tid_work(struct iowait * w)429 static 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 */
iowait_get_ib_work(struct iowait * w)438 static 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 */
iowait_ioww_to_iow(struct iowait_work * w)447 static 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
454 void iowait_cancel_work(struct iowait *w);
455 int iowait_set_work_flag(struct iowait_work *w);
456
457 #endif
458