1 /*
2  * Copyright(c) 2015-2018 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 #include <linux/delay.h>
49 #include "hfi.h"
50 #include "qp.h"
51 #include "trace.h"
52 
53 #define SC(name) SEND_CTXT_##name
54 /*
55  * Send Context functions
56  */
57 static void sc_wait_for_packet_egress(struct send_context *sc, int pause);
58 
59 /*
60  * Set the CM reset bit and wait for it to clear.  Use the provided
61  * sendctrl register.  This routine has no locking.
62  */
__cm_reset(struct hfi1_devdata * dd,u64 sendctrl)63 void __cm_reset(struct hfi1_devdata *dd, u64 sendctrl)
64 {
65 	write_csr(dd, SEND_CTRL, sendctrl | SEND_CTRL_CM_RESET_SMASK);
66 	while (1) {
67 		udelay(1);
68 		sendctrl = read_csr(dd, SEND_CTRL);
69 		if ((sendctrl & SEND_CTRL_CM_RESET_SMASK) == 0)
70 			break;
71 	}
72 }
73 
74 /* defined in header release 48 and higher */
75 #ifndef SEND_CTRL_UNSUPPORTED_VL_SHIFT
76 #define SEND_CTRL_UNSUPPORTED_VL_SHIFT 3
77 #define SEND_CTRL_UNSUPPORTED_VL_MASK 0xffull
78 #define SEND_CTRL_UNSUPPORTED_VL_SMASK (SEND_CTRL_UNSUPPORTED_VL_MASK \
79 		<< SEND_CTRL_UNSUPPORTED_VL_SHIFT)
80 #endif
81 
82 /* global control of PIO send */
pio_send_control(struct hfi1_devdata * dd,int op)83 void pio_send_control(struct hfi1_devdata *dd, int op)
84 {
85 	u64 reg, mask;
86 	unsigned long flags;
87 	int write = 1;	/* write sendctrl back */
88 	int flush = 0;	/* re-read sendctrl to make sure it is flushed */
89 	int i;
90 
91 	spin_lock_irqsave(&dd->sendctrl_lock, flags);
92 
93 	reg = read_csr(dd, SEND_CTRL);
94 	switch (op) {
95 	case PSC_GLOBAL_ENABLE:
96 		reg |= SEND_CTRL_SEND_ENABLE_SMASK;
97 	/* Fall through */
98 	case PSC_DATA_VL_ENABLE:
99 		mask = 0;
100 		for (i = 0; i < ARRAY_SIZE(dd->vld); i++)
101 			if (!dd->vld[i].mtu)
102 				mask |= BIT_ULL(i);
103 		/* Disallow sending on VLs not enabled */
104 		mask = (mask & SEND_CTRL_UNSUPPORTED_VL_MASK) <<
105 			SEND_CTRL_UNSUPPORTED_VL_SHIFT;
106 		reg = (reg & ~SEND_CTRL_UNSUPPORTED_VL_SMASK) | mask;
107 		break;
108 	case PSC_GLOBAL_DISABLE:
109 		reg &= ~SEND_CTRL_SEND_ENABLE_SMASK;
110 		break;
111 	case PSC_GLOBAL_VLARB_ENABLE:
112 		reg |= SEND_CTRL_VL_ARBITER_ENABLE_SMASK;
113 		break;
114 	case PSC_GLOBAL_VLARB_DISABLE:
115 		reg &= ~SEND_CTRL_VL_ARBITER_ENABLE_SMASK;
116 		break;
117 	case PSC_CM_RESET:
118 		__cm_reset(dd, reg);
119 		write = 0; /* CSR already written (and flushed) */
120 		break;
121 	case PSC_DATA_VL_DISABLE:
122 		reg |= SEND_CTRL_UNSUPPORTED_VL_SMASK;
123 		flush = 1;
124 		break;
125 	default:
126 		dd_dev_err(dd, "%s: invalid control %d\n", __func__, op);
127 		break;
128 	}
129 
130 	if (write) {
131 		write_csr(dd, SEND_CTRL, reg);
132 		if (flush)
133 			(void)read_csr(dd, SEND_CTRL); /* flush write */
134 	}
135 
136 	spin_unlock_irqrestore(&dd->sendctrl_lock, flags);
137 }
138 
139 /* number of send context memory pools */
140 #define NUM_SC_POOLS 2
141 
142 /* Send Context Size (SCS) wildcards */
143 #define SCS_POOL_0 -1
144 #define SCS_POOL_1 -2
145 
146 /* Send Context Count (SCC) wildcards */
147 #define SCC_PER_VL -1
148 #define SCC_PER_CPU  -2
149 #define SCC_PER_KRCVQ  -3
150 
151 /* Send Context Size (SCS) constants */
152 #define SCS_ACK_CREDITS  32
153 #define SCS_VL15_CREDITS 102	/* 3 pkts of 2048B data + 128B header */
154 
155 #define PIO_THRESHOLD_CEILING 4096
156 
157 #define PIO_WAIT_BATCH_SIZE 5
158 
159 /* default send context sizes */
160 static struct sc_config_sizes sc_config_sizes[SC_MAX] = {
161 	[SC_KERNEL] = { .size  = SCS_POOL_0,	/* even divide, pool 0 */
162 			.count = SCC_PER_VL },	/* one per NUMA */
163 	[SC_ACK]    = { .size  = SCS_ACK_CREDITS,
164 			.count = SCC_PER_KRCVQ },
165 	[SC_USER]   = { .size  = SCS_POOL_0,	/* even divide, pool 0 */
166 			.count = SCC_PER_CPU },	/* one per CPU */
167 	[SC_VL15]   = { .size  = SCS_VL15_CREDITS,
168 			.count = 1 },
169 
170 };
171 
172 /* send context memory pool configuration */
173 struct mem_pool_config {
174 	int centipercent;	/* % of memory, in 100ths of 1% */
175 	int absolute_blocks;	/* absolute block count */
176 };
177 
178 /* default memory pool configuration: 100% in pool 0 */
179 static struct mem_pool_config sc_mem_pool_config[NUM_SC_POOLS] = {
180 	/* centi%, abs blocks */
181 	{  10000,     -1 },		/* pool 0 */
182 	{      0,     -1 },		/* pool 1 */
183 };
184 
185 /* memory pool information, used when calculating final sizes */
186 struct mem_pool_info {
187 	int centipercent;	/*
188 				 * 100th of 1% of memory to use, -1 if blocks
189 				 * already set
190 				 */
191 	int count;		/* count of contexts in the pool */
192 	int blocks;		/* block size of the pool */
193 	int size;		/* context size, in blocks */
194 };
195 
196 /*
197  * Convert a pool wildcard to a valid pool index.  The wildcards
198  * start at -1 and increase negatively.  Map them as:
199  *	-1 => 0
200  *	-2 => 1
201  *	etc.
202  *
203  * Return -1 on non-wildcard input, otherwise convert to a pool number.
204  */
wildcard_to_pool(int wc)205 static int wildcard_to_pool(int wc)
206 {
207 	if (wc >= 0)
208 		return -1;	/* non-wildcard */
209 	return -wc - 1;
210 }
211 
212 static const char *sc_type_names[SC_MAX] = {
213 	"kernel",
214 	"ack",
215 	"user",
216 	"vl15"
217 };
218 
sc_type_name(int index)219 static const char *sc_type_name(int index)
220 {
221 	if (index < 0 || index >= SC_MAX)
222 		return "unknown";
223 	return sc_type_names[index];
224 }
225 
226 /*
227  * Read the send context memory pool configuration and send context
228  * size configuration.  Replace any wildcards and come up with final
229  * counts and sizes for the send context types.
230  */
init_sc_pools_and_sizes(struct hfi1_devdata * dd)231 int init_sc_pools_and_sizes(struct hfi1_devdata *dd)
232 {
233 	struct mem_pool_info mem_pool_info[NUM_SC_POOLS] = { { 0 } };
234 	int total_blocks = (chip_pio_mem_size(dd) / PIO_BLOCK_SIZE) - 1;
235 	int total_contexts = 0;
236 	int fixed_blocks;
237 	int pool_blocks;
238 	int used_blocks;
239 	int cp_total;		/* centipercent total */
240 	int ab_total;		/* absolute block total */
241 	int extra;
242 	int i;
243 
244 	/*
245 	 * When SDMA is enabled, kernel context pio packet size is capped by
246 	 * "piothreshold". Reduce pio buffer allocation for kernel context by
247 	 * setting it to a fixed size. The allocation allows 3-deep buffering
248 	 * of the largest pio packets plus up to 128 bytes header, sufficient
249 	 * to maintain verbs performance.
250 	 *
251 	 * When SDMA is disabled, keep the default pooling allocation.
252 	 */
253 	if (HFI1_CAP_IS_KSET(SDMA)) {
254 		u16 max_pkt_size = (piothreshold < PIO_THRESHOLD_CEILING) ?
255 					 piothreshold : PIO_THRESHOLD_CEILING;
256 		sc_config_sizes[SC_KERNEL].size =
257 			3 * (max_pkt_size + 128) / PIO_BLOCK_SIZE;
258 	}
259 
260 	/*
261 	 * Step 0:
262 	 *	- copy the centipercents/absolute sizes from the pool config
263 	 *	- sanity check these values
264 	 *	- add up centipercents, then later check for full value
265 	 *	- add up absolute blocks, then later check for over-commit
266 	 */
267 	cp_total = 0;
268 	ab_total = 0;
269 	for (i = 0; i < NUM_SC_POOLS; i++) {
270 		int cp = sc_mem_pool_config[i].centipercent;
271 		int ab = sc_mem_pool_config[i].absolute_blocks;
272 
273 		/*
274 		 * A negative value is "unused" or "invalid".  Both *can*
275 		 * be valid, but centipercent wins, so check that first
276 		 */
277 		if (cp >= 0) {			/* centipercent valid */
278 			cp_total += cp;
279 		} else if (ab >= 0) {		/* absolute blocks valid */
280 			ab_total += ab;
281 		} else {			/* neither valid */
282 			dd_dev_err(
283 				dd,
284 				"Send context memory pool %d: both the block count and centipercent are invalid\n",
285 				i);
286 			return -EINVAL;
287 		}
288 
289 		mem_pool_info[i].centipercent = cp;
290 		mem_pool_info[i].blocks = ab;
291 	}
292 
293 	/* do not use both % and absolute blocks for different pools */
294 	if (cp_total != 0 && ab_total != 0) {
295 		dd_dev_err(
296 			dd,
297 			"All send context memory pools must be described as either centipercent or blocks, no mixing between pools\n");
298 		return -EINVAL;
299 	}
300 
301 	/* if any percentages are present, they must add up to 100% x 100 */
302 	if (cp_total != 0 && cp_total != 10000) {
303 		dd_dev_err(
304 			dd,
305 			"Send context memory pool centipercent is %d, expecting 10000\n",
306 			cp_total);
307 		return -EINVAL;
308 	}
309 
310 	/* the absolute pool total cannot be more than the mem total */
311 	if (ab_total > total_blocks) {
312 		dd_dev_err(
313 			dd,
314 			"Send context memory pool absolute block count %d is larger than the memory size %d\n",
315 			ab_total, total_blocks);
316 		return -EINVAL;
317 	}
318 
319 	/*
320 	 * Step 2:
321 	 *	- copy from the context size config
322 	 *	- replace context type wildcard counts with real values
323 	 *	- add up non-memory pool block sizes
324 	 *	- add up memory pool user counts
325 	 */
326 	fixed_blocks = 0;
327 	for (i = 0; i < SC_MAX; i++) {
328 		int count = sc_config_sizes[i].count;
329 		int size = sc_config_sizes[i].size;
330 		int pool;
331 
332 		/*
333 		 * Sanity check count: Either a positive value or
334 		 * one of the expected wildcards is valid.  The positive
335 		 * value is checked later when we compare against total
336 		 * memory available.
337 		 */
338 		if (i == SC_ACK) {
339 			count = dd->n_krcv_queues;
340 		} else if (i == SC_KERNEL) {
341 			count = INIT_SC_PER_VL * num_vls;
342 		} else if (count == SCC_PER_CPU) {
343 			count = dd->num_rcv_contexts - dd->n_krcv_queues;
344 		} else if (count < 0) {
345 			dd_dev_err(
346 				dd,
347 				"%s send context invalid count wildcard %d\n",
348 				sc_type_name(i), count);
349 			return -EINVAL;
350 		}
351 		if (total_contexts + count > chip_send_contexts(dd))
352 			count = chip_send_contexts(dd) - total_contexts;
353 
354 		total_contexts += count;
355 
356 		/*
357 		 * Sanity check pool: The conversion will return a pool
358 		 * number or -1 if a fixed (non-negative) value.  The fixed
359 		 * value is checked later when we compare against
360 		 * total memory available.
361 		 */
362 		pool = wildcard_to_pool(size);
363 		if (pool == -1) {			/* non-wildcard */
364 			fixed_blocks += size * count;
365 		} else if (pool < NUM_SC_POOLS) {	/* valid wildcard */
366 			mem_pool_info[pool].count += count;
367 		} else {				/* invalid wildcard */
368 			dd_dev_err(
369 				dd,
370 				"%s send context invalid pool wildcard %d\n",
371 				sc_type_name(i), size);
372 			return -EINVAL;
373 		}
374 
375 		dd->sc_sizes[i].count = count;
376 		dd->sc_sizes[i].size = size;
377 	}
378 	if (fixed_blocks > total_blocks) {
379 		dd_dev_err(
380 			dd,
381 			"Send context fixed block count, %u, larger than total block count %u\n",
382 			fixed_blocks, total_blocks);
383 		return -EINVAL;
384 	}
385 
386 	/* step 3: calculate the blocks in the pools, and pool context sizes */
387 	pool_blocks = total_blocks - fixed_blocks;
388 	if (ab_total > pool_blocks) {
389 		dd_dev_err(
390 			dd,
391 			"Send context fixed pool sizes, %u, larger than pool block count %u\n",
392 			ab_total, pool_blocks);
393 		return -EINVAL;
394 	}
395 	/* subtract off the fixed pool blocks */
396 	pool_blocks -= ab_total;
397 
398 	for (i = 0; i < NUM_SC_POOLS; i++) {
399 		struct mem_pool_info *pi = &mem_pool_info[i];
400 
401 		/* % beats absolute blocks */
402 		if (pi->centipercent >= 0)
403 			pi->blocks = (pool_blocks * pi->centipercent) / 10000;
404 
405 		if (pi->blocks == 0 && pi->count != 0) {
406 			dd_dev_err(
407 				dd,
408 				"Send context memory pool %d has %u contexts, but no blocks\n",
409 				i, pi->count);
410 			return -EINVAL;
411 		}
412 		if (pi->count == 0) {
413 			/* warn about wasted blocks */
414 			if (pi->blocks != 0)
415 				dd_dev_err(
416 					dd,
417 					"Send context memory pool %d has %u blocks, but zero contexts\n",
418 					i, pi->blocks);
419 			pi->size = 0;
420 		} else {
421 			pi->size = pi->blocks / pi->count;
422 		}
423 	}
424 
425 	/* step 4: fill in the context type sizes from the pool sizes */
426 	used_blocks = 0;
427 	for (i = 0; i < SC_MAX; i++) {
428 		if (dd->sc_sizes[i].size < 0) {
429 			unsigned pool = wildcard_to_pool(dd->sc_sizes[i].size);
430 
431 			WARN_ON_ONCE(pool >= NUM_SC_POOLS);
432 			dd->sc_sizes[i].size = mem_pool_info[pool].size;
433 		}
434 		/* make sure we are not larger than what is allowed by the HW */
435 #define PIO_MAX_BLOCKS 1024
436 		if (dd->sc_sizes[i].size > PIO_MAX_BLOCKS)
437 			dd->sc_sizes[i].size = PIO_MAX_BLOCKS;
438 
439 		/* calculate our total usage */
440 		used_blocks += dd->sc_sizes[i].size * dd->sc_sizes[i].count;
441 	}
442 	extra = total_blocks - used_blocks;
443 	if (extra != 0)
444 		dd_dev_info(dd, "unused send context blocks: %d\n", extra);
445 
446 	return total_contexts;
447 }
448 
init_send_contexts(struct hfi1_devdata * dd)449 int init_send_contexts(struct hfi1_devdata *dd)
450 {
451 	u16 base;
452 	int ret, i, j, context;
453 
454 	ret = init_credit_return(dd);
455 	if (ret)
456 		return ret;
457 
458 	dd->hw_to_sw = kmalloc_array(TXE_NUM_CONTEXTS, sizeof(u8),
459 					GFP_KERNEL);
460 	dd->send_contexts = kcalloc(dd->num_send_contexts,
461 				    sizeof(struct send_context_info),
462 				    GFP_KERNEL);
463 	if (!dd->send_contexts || !dd->hw_to_sw) {
464 		kfree(dd->hw_to_sw);
465 		kfree(dd->send_contexts);
466 		free_credit_return(dd);
467 		return -ENOMEM;
468 	}
469 
470 	/* hardware context map starts with invalid send context indices */
471 	for (i = 0; i < TXE_NUM_CONTEXTS; i++)
472 		dd->hw_to_sw[i] = INVALID_SCI;
473 
474 	/*
475 	 * All send contexts have their credit sizes.  Allocate credits
476 	 * for each context one after another from the global space.
477 	 */
478 	context = 0;
479 	base = 1;
480 	for (i = 0; i < SC_MAX; i++) {
481 		struct sc_config_sizes *scs = &dd->sc_sizes[i];
482 
483 		for (j = 0; j < scs->count; j++) {
484 			struct send_context_info *sci =
485 						&dd->send_contexts[context];
486 			sci->type = i;
487 			sci->base = base;
488 			sci->credits = scs->size;
489 
490 			context++;
491 			base += scs->size;
492 		}
493 	}
494 
495 	return 0;
496 }
497 
498 /*
499  * Allocate a software index and hardware context of the given type.
500  *
501  * Must be called with dd->sc_lock held.
502  */
sc_hw_alloc(struct hfi1_devdata * dd,int type,u32 * sw_index,u32 * hw_context)503 static int sc_hw_alloc(struct hfi1_devdata *dd, int type, u32 *sw_index,
504 		       u32 *hw_context)
505 {
506 	struct send_context_info *sci;
507 	u32 index;
508 	u32 context;
509 
510 	for (index = 0, sci = &dd->send_contexts[0];
511 			index < dd->num_send_contexts; index++, sci++) {
512 		if (sci->type == type && sci->allocated == 0) {
513 			sci->allocated = 1;
514 			/* use a 1:1 mapping, but make them non-equal */
515 			context = chip_send_contexts(dd) - index - 1;
516 			dd->hw_to_sw[context] = index;
517 			*sw_index = index;
518 			*hw_context = context;
519 			return 0; /* success */
520 		}
521 	}
522 	dd_dev_err(dd, "Unable to locate a free type %d send context\n", type);
523 	return -ENOSPC;
524 }
525 
526 /*
527  * Free the send context given by its software index.
528  *
529  * Must be called with dd->sc_lock held.
530  */
sc_hw_free(struct hfi1_devdata * dd,u32 sw_index,u32 hw_context)531 static void sc_hw_free(struct hfi1_devdata *dd, u32 sw_index, u32 hw_context)
532 {
533 	struct send_context_info *sci;
534 
535 	sci = &dd->send_contexts[sw_index];
536 	if (!sci->allocated) {
537 		dd_dev_err(dd, "%s: sw_index %u not allocated? hw_context %u\n",
538 			   __func__, sw_index, hw_context);
539 	}
540 	sci->allocated = 0;
541 	dd->hw_to_sw[hw_context] = INVALID_SCI;
542 }
543 
544 /* return the base context of a context in a group */
group_context(u32 context,u32 group)545 static inline u32 group_context(u32 context, u32 group)
546 {
547 	return (context >> group) << group;
548 }
549 
550 /* return the size of a group */
group_size(u32 group)551 static inline u32 group_size(u32 group)
552 {
553 	return 1 << group;
554 }
555 
556 /*
557  * Obtain the credit return addresses, kernel virtual and bus, for the
558  * given sc.
559  *
560  * To understand this routine:
561  * o va and dma are arrays of struct credit_return.  One for each physical
562  *   send context, per NUMA.
563  * o Each send context always looks in its relative location in a struct
564  *   credit_return for its credit return.
565  * o Each send context in a group must have its return address CSR programmed
566  *   with the same value.  Use the address of the first send context in the
567  *   group.
568  */
cr_group_addresses(struct send_context * sc,dma_addr_t * dma)569 static void cr_group_addresses(struct send_context *sc, dma_addr_t *dma)
570 {
571 	u32 gc = group_context(sc->hw_context, sc->group);
572 	u32 index = sc->hw_context & 0x7;
573 
574 	sc->hw_free = &sc->dd->cr_base[sc->node].va[gc].cr[index];
575 	*dma = (unsigned long)
576 	       &((struct credit_return *)sc->dd->cr_base[sc->node].dma)[gc];
577 }
578 
579 /*
580  * Work queue function triggered in error interrupt routine for
581  * kernel contexts.
582  */
sc_halted(struct work_struct * work)583 static void sc_halted(struct work_struct *work)
584 {
585 	struct send_context *sc;
586 
587 	sc = container_of(work, struct send_context, halt_work);
588 	sc_restart(sc);
589 }
590 
591 /*
592  * Calculate PIO block threshold for this send context using the given MTU.
593  * Trigger a return when one MTU plus optional header of credits remain.
594  *
595  * Parameter mtu is in bytes.
596  * Parameter hdrqentsize is in DWORDs.
597  *
598  * Return value is what to write into the CSR: trigger return when
599  * unreturned credits pass this count.
600  */
sc_mtu_to_threshold(struct send_context * sc,u32 mtu,u32 hdrqentsize)601 u32 sc_mtu_to_threshold(struct send_context *sc, u32 mtu, u32 hdrqentsize)
602 {
603 	u32 release_credits;
604 	u32 threshold;
605 
606 	/* add in the header size, then divide by the PIO block size */
607 	mtu += hdrqentsize << 2;
608 	release_credits = DIV_ROUND_UP(mtu, PIO_BLOCK_SIZE);
609 
610 	/* check against this context's credits */
611 	if (sc->credits <= release_credits)
612 		threshold = 1;
613 	else
614 		threshold = sc->credits - release_credits;
615 
616 	return threshold;
617 }
618 
619 /*
620  * Calculate credit threshold in terms of percent of the allocated credits.
621  * Trigger when unreturned credits equal or exceed the percentage of the whole.
622  *
623  * Return value is what to write into the CSR: trigger return when
624  * unreturned credits pass this count.
625  */
sc_percent_to_threshold(struct send_context * sc,u32 percent)626 u32 sc_percent_to_threshold(struct send_context *sc, u32 percent)
627 {
628 	return (sc->credits * percent) / 100;
629 }
630 
631 /*
632  * Set the credit return threshold.
633  */
sc_set_cr_threshold(struct send_context * sc,u32 new_threshold)634 void sc_set_cr_threshold(struct send_context *sc, u32 new_threshold)
635 {
636 	unsigned long flags;
637 	u32 old_threshold;
638 	int force_return = 0;
639 
640 	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
641 
642 	old_threshold = (sc->credit_ctrl >>
643 				SC(CREDIT_CTRL_THRESHOLD_SHIFT))
644 			 & SC(CREDIT_CTRL_THRESHOLD_MASK);
645 
646 	if (new_threshold != old_threshold) {
647 		sc->credit_ctrl =
648 			(sc->credit_ctrl
649 				& ~SC(CREDIT_CTRL_THRESHOLD_SMASK))
650 			| ((new_threshold
651 				& SC(CREDIT_CTRL_THRESHOLD_MASK))
652 			   << SC(CREDIT_CTRL_THRESHOLD_SHIFT));
653 		write_kctxt_csr(sc->dd, sc->hw_context,
654 				SC(CREDIT_CTRL), sc->credit_ctrl);
655 
656 		/* force a credit return on change to avoid a possible stall */
657 		force_return = 1;
658 	}
659 
660 	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
661 
662 	if (force_return)
663 		sc_return_credits(sc);
664 }
665 
666 /*
667  * set_pio_integrity
668  *
669  * Set the CHECK_ENABLE register for the send context 'sc'.
670  */
set_pio_integrity(struct send_context * sc)671 void set_pio_integrity(struct send_context *sc)
672 {
673 	struct hfi1_devdata *dd = sc->dd;
674 	u32 hw_context = sc->hw_context;
675 	int type = sc->type;
676 
677 	write_kctxt_csr(dd, hw_context,
678 			SC(CHECK_ENABLE),
679 			hfi1_pkt_default_send_ctxt_mask(dd, type));
680 }
681 
get_buffers_allocated(struct send_context * sc)682 static u32 get_buffers_allocated(struct send_context *sc)
683 {
684 	int cpu;
685 	u32 ret = 0;
686 
687 	for_each_possible_cpu(cpu)
688 		ret += *per_cpu_ptr(sc->buffers_allocated, cpu);
689 	return ret;
690 }
691 
reset_buffers_allocated(struct send_context * sc)692 static void reset_buffers_allocated(struct send_context *sc)
693 {
694 	int cpu;
695 
696 	for_each_possible_cpu(cpu)
697 		(*per_cpu_ptr(sc->buffers_allocated, cpu)) = 0;
698 }
699 
700 /*
701  * Allocate a NUMA relative send context structure of the given type along
702  * with a HW context.
703  */
sc_alloc(struct hfi1_devdata * dd,int type,uint hdrqentsize,int numa)704 struct send_context *sc_alloc(struct hfi1_devdata *dd, int type,
705 			      uint hdrqentsize, int numa)
706 {
707 	struct send_context_info *sci;
708 	struct send_context *sc = NULL;
709 	dma_addr_t dma;
710 	unsigned long flags;
711 	u64 reg;
712 	u32 thresh;
713 	u32 sw_index;
714 	u32 hw_context;
715 	int ret;
716 	u8 opval, opmask;
717 
718 	/* do not allocate while frozen */
719 	if (dd->flags & HFI1_FROZEN)
720 		return NULL;
721 
722 	sc = kzalloc_node(sizeof(*sc), GFP_KERNEL, numa);
723 	if (!sc)
724 		return NULL;
725 
726 	sc->buffers_allocated = alloc_percpu(u32);
727 	if (!sc->buffers_allocated) {
728 		kfree(sc);
729 		dd_dev_err(dd,
730 			   "Cannot allocate buffers_allocated per cpu counters\n"
731 			  );
732 		return NULL;
733 	}
734 
735 	spin_lock_irqsave(&dd->sc_lock, flags);
736 	ret = sc_hw_alloc(dd, type, &sw_index, &hw_context);
737 	if (ret) {
738 		spin_unlock_irqrestore(&dd->sc_lock, flags);
739 		free_percpu(sc->buffers_allocated);
740 		kfree(sc);
741 		return NULL;
742 	}
743 
744 	sci = &dd->send_contexts[sw_index];
745 	sci->sc = sc;
746 
747 	sc->dd = dd;
748 	sc->node = numa;
749 	sc->type = type;
750 	spin_lock_init(&sc->alloc_lock);
751 	spin_lock_init(&sc->release_lock);
752 	spin_lock_init(&sc->credit_ctrl_lock);
753 	INIT_LIST_HEAD(&sc->piowait);
754 	INIT_WORK(&sc->halt_work, sc_halted);
755 	init_waitqueue_head(&sc->halt_wait);
756 
757 	/* grouping is always single context for now */
758 	sc->group = 0;
759 
760 	sc->sw_index = sw_index;
761 	sc->hw_context = hw_context;
762 	cr_group_addresses(sc, &dma);
763 	sc->credits = sci->credits;
764 	sc->size = sc->credits * PIO_BLOCK_SIZE;
765 
766 /* PIO Send Memory Address details */
767 #define PIO_ADDR_CONTEXT_MASK 0xfful
768 #define PIO_ADDR_CONTEXT_SHIFT 16
769 	sc->base_addr = dd->piobase + ((hw_context & PIO_ADDR_CONTEXT_MASK)
770 					<< PIO_ADDR_CONTEXT_SHIFT);
771 
772 	/* set base and credits */
773 	reg = ((sci->credits & SC(CTRL_CTXT_DEPTH_MASK))
774 					<< SC(CTRL_CTXT_DEPTH_SHIFT))
775 		| ((sci->base & SC(CTRL_CTXT_BASE_MASK))
776 					<< SC(CTRL_CTXT_BASE_SHIFT));
777 	write_kctxt_csr(dd, hw_context, SC(CTRL), reg);
778 
779 	set_pio_integrity(sc);
780 
781 	/* unmask all errors */
782 	write_kctxt_csr(dd, hw_context, SC(ERR_MASK), (u64)-1);
783 
784 	/* set the default partition key */
785 	write_kctxt_csr(dd, hw_context, SC(CHECK_PARTITION_KEY),
786 			(SC(CHECK_PARTITION_KEY_VALUE_MASK) &
787 			 DEFAULT_PKEY) <<
788 			SC(CHECK_PARTITION_KEY_VALUE_SHIFT));
789 
790 	/* per context type checks */
791 	if (type == SC_USER) {
792 		opval = USER_OPCODE_CHECK_VAL;
793 		opmask = USER_OPCODE_CHECK_MASK;
794 	} else {
795 		opval = OPCODE_CHECK_VAL_DISABLED;
796 		opmask = OPCODE_CHECK_MASK_DISABLED;
797 	}
798 
799 	/* set the send context check opcode mask and value */
800 	write_kctxt_csr(dd, hw_context, SC(CHECK_OPCODE),
801 			((u64)opmask << SC(CHECK_OPCODE_MASK_SHIFT)) |
802 			((u64)opval << SC(CHECK_OPCODE_VALUE_SHIFT)));
803 
804 	/* set up credit return */
805 	reg = dma & SC(CREDIT_RETURN_ADDR_ADDRESS_SMASK);
806 	write_kctxt_csr(dd, hw_context, SC(CREDIT_RETURN_ADDR), reg);
807 
808 	/*
809 	 * Calculate the initial credit return threshold.
810 	 *
811 	 * For Ack contexts, set a threshold for half the credits.
812 	 * For User contexts use the given percentage.  This has been
813 	 * sanitized on driver start-up.
814 	 * For Kernel contexts, use the default MTU plus a header
815 	 * or half the credits, whichever is smaller. This should
816 	 * work for both the 3-deep buffering allocation and the
817 	 * pooling allocation.
818 	 */
819 	if (type == SC_ACK) {
820 		thresh = sc_percent_to_threshold(sc, 50);
821 	} else if (type == SC_USER) {
822 		thresh = sc_percent_to_threshold(sc,
823 						 user_credit_return_threshold);
824 	} else { /* kernel */
825 		thresh = min(sc_percent_to_threshold(sc, 50),
826 			     sc_mtu_to_threshold(sc, hfi1_max_mtu,
827 						 hdrqentsize));
828 	}
829 	reg = thresh << SC(CREDIT_CTRL_THRESHOLD_SHIFT);
830 	/* add in early return */
831 	if (type == SC_USER && HFI1_CAP_IS_USET(EARLY_CREDIT_RETURN))
832 		reg |= SC(CREDIT_CTRL_EARLY_RETURN_SMASK);
833 	else if (HFI1_CAP_IS_KSET(EARLY_CREDIT_RETURN)) /* kernel, ack */
834 		reg |= SC(CREDIT_CTRL_EARLY_RETURN_SMASK);
835 
836 	/* set up write-through credit_ctrl */
837 	sc->credit_ctrl = reg;
838 	write_kctxt_csr(dd, hw_context, SC(CREDIT_CTRL), reg);
839 
840 	/* User send contexts should not allow sending on VL15 */
841 	if (type == SC_USER) {
842 		reg = 1ULL << 15;
843 		write_kctxt_csr(dd, hw_context, SC(CHECK_VL), reg);
844 	}
845 
846 	spin_unlock_irqrestore(&dd->sc_lock, flags);
847 
848 	/*
849 	 * Allocate shadow ring to track outstanding PIO buffers _after_
850 	 * unlocking.  We don't know the size until the lock is held and
851 	 * we can't allocate while the lock is held.  No one is using
852 	 * the context yet, so allocate it now.
853 	 *
854 	 * User contexts do not get a shadow ring.
855 	 */
856 	if (type != SC_USER) {
857 		/*
858 		 * Size the shadow ring 1 larger than the number of credits
859 		 * so head == tail can mean empty.
860 		 */
861 		sc->sr_size = sci->credits + 1;
862 		sc->sr = kcalloc_node(sc->sr_size,
863 				      sizeof(union pio_shadow_ring),
864 				      GFP_KERNEL, numa);
865 		if (!sc->sr) {
866 			sc_free(sc);
867 			return NULL;
868 		}
869 	}
870 
871 	hfi1_cdbg(PIO,
872 		  "Send context %u(%u) %s group %u credits %u credit_ctrl 0x%llx threshold %u\n",
873 		  sw_index,
874 		  hw_context,
875 		  sc_type_name(type),
876 		  sc->group,
877 		  sc->credits,
878 		  sc->credit_ctrl,
879 		  thresh);
880 
881 	return sc;
882 }
883 
884 /* free a per-NUMA send context structure */
sc_free(struct send_context * sc)885 void sc_free(struct send_context *sc)
886 {
887 	struct hfi1_devdata *dd;
888 	unsigned long flags;
889 	u32 sw_index;
890 	u32 hw_context;
891 
892 	if (!sc)
893 		return;
894 
895 	sc->flags |= SCF_IN_FREE;	/* ensure no restarts */
896 	dd = sc->dd;
897 	if (!list_empty(&sc->piowait))
898 		dd_dev_err(dd, "piowait list not empty!\n");
899 	sw_index = sc->sw_index;
900 	hw_context = sc->hw_context;
901 	sc_disable(sc);	/* make sure the HW is disabled */
902 	flush_work(&sc->halt_work);
903 
904 	spin_lock_irqsave(&dd->sc_lock, flags);
905 	dd->send_contexts[sw_index].sc = NULL;
906 
907 	/* clear/disable all registers set in sc_alloc */
908 	write_kctxt_csr(dd, hw_context, SC(CTRL), 0);
909 	write_kctxt_csr(dd, hw_context, SC(CHECK_ENABLE), 0);
910 	write_kctxt_csr(dd, hw_context, SC(ERR_MASK), 0);
911 	write_kctxt_csr(dd, hw_context, SC(CHECK_PARTITION_KEY), 0);
912 	write_kctxt_csr(dd, hw_context, SC(CHECK_OPCODE), 0);
913 	write_kctxt_csr(dd, hw_context, SC(CREDIT_RETURN_ADDR), 0);
914 	write_kctxt_csr(dd, hw_context, SC(CREDIT_CTRL), 0);
915 
916 	/* release the index and context for re-use */
917 	sc_hw_free(dd, sw_index, hw_context);
918 	spin_unlock_irqrestore(&dd->sc_lock, flags);
919 
920 	kfree(sc->sr);
921 	free_percpu(sc->buffers_allocated);
922 	kfree(sc);
923 }
924 
925 /* disable the context */
sc_disable(struct send_context * sc)926 void sc_disable(struct send_context *sc)
927 {
928 	u64 reg;
929 	struct pio_buf *pbuf;
930 
931 	if (!sc)
932 		return;
933 
934 	/* do all steps, even if already disabled */
935 	spin_lock_irq(&sc->alloc_lock);
936 	reg = read_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL));
937 	reg &= ~SC(CTRL_CTXT_ENABLE_SMASK);
938 	sc->flags &= ~SCF_ENABLED;
939 	sc_wait_for_packet_egress(sc, 1);
940 	write_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL), reg);
941 
942 	/*
943 	 * Flush any waiters.  Once the context is disabled,
944 	 * credit return interrupts are stopped (although there
945 	 * could be one in-process when the context is disabled).
946 	 * Wait one microsecond for any lingering interrupts, then
947 	 * proceed with the flush.
948 	 */
949 	udelay(1);
950 	spin_lock(&sc->release_lock);
951 	if (sc->sr) {	/* this context has a shadow ring */
952 		while (sc->sr_tail != sc->sr_head) {
953 			pbuf = &sc->sr[sc->sr_tail].pbuf;
954 			if (pbuf->cb)
955 				(*pbuf->cb)(pbuf->arg, PRC_SC_DISABLE);
956 			sc->sr_tail++;
957 			if (sc->sr_tail >= sc->sr_size)
958 				sc->sr_tail = 0;
959 		}
960 	}
961 	spin_unlock(&sc->release_lock);
962 	spin_unlock_irq(&sc->alloc_lock);
963 }
964 
965 /* return SendEgressCtxtStatus.PacketOccupancy */
packet_occupancy(u64 reg)966 static u64 packet_occupancy(u64 reg)
967 {
968 	return (reg &
969 		SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_PACKET_OCCUPANCY_SMASK)
970 		>> SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_PACKET_OCCUPANCY_SHIFT;
971 }
972 
973 /* is egress halted on the context? */
egress_halted(u64 reg)974 static bool egress_halted(u64 reg)
975 {
976 	return !!(reg & SEND_EGRESS_CTXT_STATUS_CTXT_EGRESS_HALT_STATUS_SMASK);
977 }
978 
979 /* is the send context halted? */
is_sc_halted(struct hfi1_devdata * dd,u32 hw_context)980 static bool is_sc_halted(struct hfi1_devdata *dd, u32 hw_context)
981 {
982 	return !!(read_kctxt_csr(dd, hw_context, SC(STATUS)) &
983 		  SC(STATUS_CTXT_HALTED_SMASK));
984 }
985 
986 /**
987  * sc_wait_for_packet_egress
988  * @sc: valid send context
989  * @pause: wait for credit return
990  *
991  * Wait for packet egress, optionally pause for credit return
992  *
993  * Egress halt and Context halt are not necessarily the same thing, so
994  * check for both.
995  *
996  * NOTE: The context halt bit may not be set immediately.  Because of this,
997  * it is necessary to check the SW SFC_HALTED bit (set in the IRQ) and the HW
998  * context bit to determine if the context is halted.
999  */
sc_wait_for_packet_egress(struct send_context * sc,int pause)1000 static void sc_wait_for_packet_egress(struct send_context *sc, int pause)
1001 {
1002 	struct hfi1_devdata *dd = sc->dd;
1003 	u64 reg = 0;
1004 	u64 reg_prev;
1005 	u32 loop = 0;
1006 
1007 	while (1) {
1008 		reg_prev = reg;
1009 		reg = read_csr(dd, sc->hw_context * 8 +
1010 			       SEND_EGRESS_CTXT_STATUS);
1011 		/* done if any halt bits, SW or HW are set */
1012 		if (sc->flags & SCF_HALTED ||
1013 		    is_sc_halted(dd, sc->hw_context) || egress_halted(reg))
1014 			break;
1015 		reg = packet_occupancy(reg);
1016 		if (reg == 0)
1017 			break;
1018 		/* counter is reset if occupancy count changes */
1019 		if (reg != reg_prev)
1020 			loop = 0;
1021 		if (loop > 50000) {
1022 			/* timed out - bounce the link */
1023 			dd_dev_err(dd,
1024 				   "%s: context %u(%u) timeout waiting for packets to egress, remaining count %u, bouncing link\n",
1025 				   __func__, sc->sw_index,
1026 				   sc->hw_context, (u32)reg);
1027 			queue_work(dd->pport->link_wq,
1028 				   &dd->pport->link_bounce_work);
1029 			break;
1030 		}
1031 		loop++;
1032 		udelay(1);
1033 	}
1034 
1035 	if (pause)
1036 		/* Add additional delay to ensure chip returns all credits */
1037 		pause_for_credit_return(dd);
1038 }
1039 
sc_wait(struct hfi1_devdata * dd)1040 void sc_wait(struct hfi1_devdata *dd)
1041 {
1042 	int i;
1043 
1044 	for (i = 0; i < dd->num_send_contexts; i++) {
1045 		struct send_context *sc = dd->send_contexts[i].sc;
1046 
1047 		if (!sc)
1048 			continue;
1049 		sc_wait_for_packet_egress(sc, 0);
1050 	}
1051 }
1052 
1053 /*
1054  * Restart a context after it has been halted due to error.
1055  *
1056  * If the first step fails - wait for the halt to be asserted, return early.
1057  * Otherwise complain about timeouts but keep going.
1058  *
1059  * It is expected that allocations (enabled flag bit) have been shut off
1060  * already (only applies to kernel contexts).
1061  */
sc_restart(struct send_context * sc)1062 int sc_restart(struct send_context *sc)
1063 {
1064 	struct hfi1_devdata *dd = sc->dd;
1065 	u64 reg;
1066 	u32 loop;
1067 	int count;
1068 
1069 	/* bounce off if not halted, or being free'd */
1070 	if (!(sc->flags & SCF_HALTED) || (sc->flags & SCF_IN_FREE))
1071 		return -EINVAL;
1072 
1073 	dd_dev_info(dd, "restarting send context %u(%u)\n", sc->sw_index,
1074 		    sc->hw_context);
1075 
1076 	/*
1077 	 * Step 1: Wait for the context to actually halt.
1078 	 *
1079 	 * The error interrupt is asynchronous to actually setting halt
1080 	 * on the context.
1081 	 */
1082 	loop = 0;
1083 	while (1) {
1084 		reg = read_kctxt_csr(dd, sc->hw_context, SC(STATUS));
1085 		if (reg & SC(STATUS_CTXT_HALTED_SMASK))
1086 			break;
1087 		if (loop > 100) {
1088 			dd_dev_err(dd, "%s: context %u(%u) not halting, skipping\n",
1089 				   __func__, sc->sw_index, sc->hw_context);
1090 			return -ETIME;
1091 		}
1092 		loop++;
1093 		udelay(1);
1094 	}
1095 
1096 	/*
1097 	 * Step 2: Ensure no users are still trying to write to PIO.
1098 	 *
1099 	 * For kernel contexts, we have already turned off buffer allocation.
1100 	 * Now wait for the buffer count to go to zero.
1101 	 *
1102 	 * For user contexts, the user handling code has cut off write access
1103 	 * to the context's PIO pages before calling this routine and will
1104 	 * restore write access after this routine returns.
1105 	 */
1106 	if (sc->type != SC_USER) {
1107 		/* kernel context */
1108 		loop = 0;
1109 		while (1) {
1110 			count = get_buffers_allocated(sc);
1111 			if (count == 0)
1112 				break;
1113 			if (loop > 100) {
1114 				dd_dev_err(dd,
1115 					   "%s: context %u(%u) timeout waiting for PIO buffers to zero, remaining %d\n",
1116 					   __func__, sc->sw_index,
1117 					   sc->hw_context, count);
1118 			}
1119 			loop++;
1120 			udelay(1);
1121 		}
1122 	}
1123 
1124 	/*
1125 	 * Step 3: Wait for all packets to egress.
1126 	 * This is done while disabling the send context
1127 	 *
1128 	 * Step 4: Disable the context
1129 	 *
1130 	 * This is a superset of the halt.  After the disable, the
1131 	 * errors can be cleared.
1132 	 */
1133 	sc_disable(sc);
1134 
1135 	/*
1136 	 * Step 5: Enable the context
1137 	 *
1138 	 * This enable will clear the halted flag and per-send context
1139 	 * error flags.
1140 	 */
1141 	return sc_enable(sc);
1142 }
1143 
1144 /*
1145  * PIO freeze processing.  To be called after the TXE block is fully frozen.
1146  * Go through all frozen send contexts and disable them.  The contexts are
1147  * already stopped by the freeze.
1148  */
pio_freeze(struct hfi1_devdata * dd)1149 void pio_freeze(struct hfi1_devdata *dd)
1150 {
1151 	struct send_context *sc;
1152 	int i;
1153 
1154 	for (i = 0; i < dd->num_send_contexts; i++) {
1155 		sc = dd->send_contexts[i].sc;
1156 		/*
1157 		 * Don't disable unallocated, unfrozen, or user send contexts.
1158 		 * User send contexts will be disabled when the process
1159 		 * calls into the driver to reset its context.
1160 		 */
1161 		if (!sc || !(sc->flags & SCF_FROZEN) || sc->type == SC_USER)
1162 			continue;
1163 
1164 		/* only need to disable, the context is already stopped */
1165 		sc_disable(sc);
1166 	}
1167 }
1168 
1169 /*
1170  * Unfreeze PIO for kernel send contexts.  The precondition for calling this
1171  * is that all PIO send contexts have been disabled and the SPC freeze has
1172  * been cleared.  Now perform the last step and re-enable each kernel context.
1173  * User (PSM) processing will occur when PSM calls into the kernel to
1174  * acknowledge the freeze.
1175  */
pio_kernel_unfreeze(struct hfi1_devdata * dd)1176 void pio_kernel_unfreeze(struct hfi1_devdata *dd)
1177 {
1178 	struct send_context *sc;
1179 	int i;
1180 
1181 	for (i = 0; i < dd->num_send_contexts; i++) {
1182 		sc = dd->send_contexts[i].sc;
1183 		if (!sc || !(sc->flags & SCF_FROZEN) || sc->type == SC_USER)
1184 			continue;
1185 		if (sc->flags & SCF_LINK_DOWN)
1186 			continue;
1187 
1188 		sc_enable(sc);	/* will clear the sc frozen flag */
1189 	}
1190 }
1191 
1192 /**
1193  * pio_kernel_linkup() - Re-enable send contexts after linkup event
1194  * @dd: valid devive data
1195  *
1196  * When the link goes down, the freeze path is taken.  However, a link down
1197  * event is different from a freeze because if the send context is re-enabled
1198  * whowever is sending data will start sending data again, which will hang
1199  * any QP that is sending data.
1200  *
1201  * The freeze path now looks at the type of event that occurs and takes this
1202  * path for link down event.
1203  */
pio_kernel_linkup(struct hfi1_devdata * dd)1204 void pio_kernel_linkup(struct hfi1_devdata *dd)
1205 {
1206 	struct send_context *sc;
1207 	int i;
1208 
1209 	for (i = 0; i < dd->num_send_contexts; i++) {
1210 		sc = dd->send_contexts[i].sc;
1211 		if (!sc || !(sc->flags & SCF_LINK_DOWN) || sc->type == SC_USER)
1212 			continue;
1213 
1214 		sc_enable(sc);	/* will clear the sc link down flag */
1215 	}
1216 }
1217 
1218 /*
1219  * Wait for the SendPioInitCtxt.PioInitInProgress bit to clear.
1220  * Returns:
1221  *	-ETIMEDOUT - if we wait too long
1222  *	-EIO	   - if there was an error
1223  */
pio_init_wait_progress(struct hfi1_devdata * dd)1224 static int pio_init_wait_progress(struct hfi1_devdata *dd)
1225 {
1226 	u64 reg;
1227 	int max, count = 0;
1228 
1229 	/* max is the longest possible HW init time / delay */
1230 	max = (dd->icode == ICODE_FPGA_EMULATION) ? 120 : 5;
1231 	while (1) {
1232 		reg = read_csr(dd, SEND_PIO_INIT_CTXT);
1233 		if (!(reg & SEND_PIO_INIT_CTXT_PIO_INIT_IN_PROGRESS_SMASK))
1234 			break;
1235 		if (count >= max)
1236 			return -ETIMEDOUT;
1237 		udelay(5);
1238 		count++;
1239 	}
1240 
1241 	return reg & SEND_PIO_INIT_CTXT_PIO_INIT_ERR_SMASK ? -EIO : 0;
1242 }
1243 
1244 /*
1245  * Reset all of the send contexts to their power-on state.  Used
1246  * only during manual init - no lock against sc_enable needed.
1247  */
pio_reset_all(struct hfi1_devdata * dd)1248 void pio_reset_all(struct hfi1_devdata *dd)
1249 {
1250 	int ret;
1251 
1252 	/* make sure the init engine is not busy */
1253 	ret = pio_init_wait_progress(dd);
1254 	/* ignore any timeout */
1255 	if (ret == -EIO) {
1256 		/* clear the error */
1257 		write_csr(dd, SEND_PIO_ERR_CLEAR,
1258 			  SEND_PIO_ERR_CLEAR_PIO_INIT_SM_IN_ERR_SMASK);
1259 	}
1260 
1261 	/* reset init all */
1262 	write_csr(dd, SEND_PIO_INIT_CTXT,
1263 		  SEND_PIO_INIT_CTXT_PIO_ALL_CTXT_INIT_SMASK);
1264 	udelay(2);
1265 	ret = pio_init_wait_progress(dd);
1266 	if (ret < 0) {
1267 		dd_dev_err(dd,
1268 			   "PIO send context init %s while initializing all PIO blocks\n",
1269 			   ret == -ETIMEDOUT ? "is stuck" : "had an error");
1270 	}
1271 }
1272 
1273 /* enable the context */
sc_enable(struct send_context * sc)1274 int sc_enable(struct send_context *sc)
1275 {
1276 	u64 sc_ctrl, reg, pio;
1277 	struct hfi1_devdata *dd;
1278 	unsigned long flags;
1279 	int ret = 0;
1280 
1281 	if (!sc)
1282 		return -EINVAL;
1283 	dd = sc->dd;
1284 
1285 	/*
1286 	 * Obtain the allocator lock to guard against any allocation
1287 	 * attempts (which should not happen prior to context being
1288 	 * enabled). On the release/disable side we don't need to
1289 	 * worry about locking since the releaser will not do anything
1290 	 * if the context accounting values have not changed.
1291 	 */
1292 	spin_lock_irqsave(&sc->alloc_lock, flags);
1293 	sc_ctrl = read_kctxt_csr(dd, sc->hw_context, SC(CTRL));
1294 	if ((sc_ctrl & SC(CTRL_CTXT_ENABLE_SMASK)))
1295 		goto unlock; /* already enabled */
1296 
1297 	/* IMPORTANT: only clear free and fill if transitioning 0 -> 1 */
1298 
1299 	*sc->hw_free = 0;
1300 	sc->free = 0;
1301 	sc->alloc_free = 0;
1302 	sc->fill = 0;
1303 	sc->fill_wrap = 0;
1304 	sc->sr_head = 0;
1305 	sc->sr_tail = 0;
1306 	sc->flags = 0;
1307 	/* the alloc lock insures no fast path allocation */
1308 	reset_buffers_allocated(sc);
1309 
1310 	/*
1311 	 * Clear all per-context errors.  Some of these will be set when
1312 	 * we are re-enabling after a context halt.  Now that the context
1313 	 * is disabled, the halt will not clear until after the PIO init
1314 	 * engine runs below.
1315 	 */
1316 	reg = read_kctxt_csr(dd, sc->hw_context, SC(ERR_STATUS));
1317 	if (reg)
1318 		write_kctxt_csr(dd, sc->hw_context, SC(ERR_CLEAR), reg);
1319 
1320 	/*
1321 	 * The HW PIO initialization engine can handle only one init
1322 	 * request at a time. Serialize access to each device's engine.
1323 	 */
1324 	spin_lock(&dd->sc_init_lock);
1325 	/*
1326 	 * Since access to this code block is serialized and
1327 	 * each access waits for the initialization to complete
1328 	 * before releasing the lock, the PIO initialization engine
1329 	 * should not be in use, so we don't have to wait for the
1330 	 * InProgress bit to go down.
1331 	 */
1332 	pio = ((sc->hw_context & SEND_PIO_INIT_CTXT_PIO_CTXT_NUM_MASK) <<
1333 	       SEND_PIO_INIT_CTXT_PIO_CTXT_NUM_SHIFT) |
1334 		SEND_PIO_INIT_CTXT_PIO_SINGLE_CTXT_INIT_SMASK;
1335 	write_csr(dd, SEND_PIO_INIT_CTXT, pio);
1336 	/*
1337 	 * Wait until the engine is done.  Give the chip the required time
1338 	 * so, hopefully, we read the register just once.
1339 	 */
1340 	udelay(2);
1341 	ret = pio_init_wait_progress(dd);
1342 	spin_unlock(&dd->sc_init_lock);
1343 	if (ret) {
1344 		dd_dev_err(dd,
1345 			   "sctxt%u(%u): Context not enabled due to init failure %d\n",
1346 			   sc->sw_index, sc->hw_context, ret);
1347 		goto unlock;
1348 	}
1349 
1350 	/*
1351 	 * All is well. Enable the context.
1352 	 */
1353 	sc_ctrl |= SC(CTRL_CTXT_ENABLE_SMASK);
1354 	write_kctxt_csr(dd, sc->hw_context, SC(CTRL), sc_ctrl);
1355 	/*
1356 	 * Read SendCtxtCtrl to force the write out and prevent a timing
1357 	 * hazard where a PIO write may reach the context before the enable.
1358 	 */
1359 	read_kctxt_csr(dd, sc->hw_context, SC(CTRL));
1360 	sc->flags |= SCF_ENABLED;
1361 
1362 unlock:
1363 	spin_unlock_irqrestore(&sc->alloc_lock, flags);
1364 
1365 	return ret;
1366 }
1367 
1368 /* force a credit return on the context */
sc_return_credits(struct send_context * sc)1369 void sc_return_credits(struct send_context *sc)
1370 {
1371 	if (!sc)
1372 		return;
1373 
1374 	/* a 0->1 transition schedules a credit return */
1375 	write_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE),
1376 			SC(CREDIT_FORCE_FORCE_RETURN_SMASK));
1377 	/*
1378 	 * Ensure that the write is flushed and the credit return is
1379 	 * scheduled. We care more about the 0 -> 1 transition.
1380 	 */
1381 	read_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE));
1382 	/* set back to 0 for next time */
1383 	write_kctxt_csr(sc->dd, sc->hw_context, SC(CREDIT_FORCE), 0);
1384 }
1385 
1386 /* allow all in-flight packets to drain on the context */
sc_flush(struct send_context * sc)1387 void sc_flush(struct send_context *sc)
1388 {
1389 	if (!sc)
1390 		return;
1391 
1392 	sc_wait_for_packet_egress(sc, 1);
1393 }
1394 
1395 /* drop all packets on the context, no waiting until they are sent */
sc_drop(struct send_context * sc)1396 void sc_drop(struct send_context *sc)
1397 {
1398 	if (!sc)
1399 		return;
1400 
1401 	dd_dev_info(sc->dd, "%s: context %u(%u) - not implemented\n",
1402 		    __func__, sc->sw_index, sc->hw_context);
1403 }
1404 
1405 /*
1406  * Start the software reaction to a context halt or SPC freeze:
1407  *	- mark the context as halted or frozen
1408  *	- stop buffer allocations
1409  *
1410  * Called from the error interrupt.  Other work is deferred until
1411  * out of the interrupt.
1412  */
sc_stop(struct send_context * sc,int flag)1413 void sc_stop(struct send_context *sc, int flag)
1414 {
1415 	unsigned long flags;
1416 
1417 	/* stop buffer allocations */
1418 	spin_lock_irqsave(&sc->alloc_lock, flags);
1419 	/* mark the context */
1420 	sc->flags |= flag;
1421 	sc->flags &= ~SCF_ENABLED;
1422 	spin_unlock_irqrestore(&sc->alloc_lock, flags);
1423 	wake_up(&sc->halt_wait);
1424 }
1425 
1426 #define BLOCK_DWORDS (PIO_BLOCK_SIZE / sizeof(u32))
1427 #define dwords_to_blocks(x) DIV_ROUND_UP(x, BLOCK_DWORDS)
1428 
1429 /*
1430  * The send context buffer "allocator".
1431  *
1432  * @sc: the PIO send context we are allocating from
1433  * @len: length of whole packet - including PBC - in dwords
1434  * @cb: optional callback to call when the buffer is finished sending
1435  * @arg: argument for cb
1436  *
1437  * Return a pointer to a PIO buffer if successful, NULL if not enough room.
1438  */
sc_buffer_alloc(struct send_context * sc,u32 dw_len,pio_release_cb cb,void * arg)1439 struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len,
1440 				pio_release_cb cb, void *arg)
1441 {
1442 	struct pio_buf *pbuf = NULL;
1443 	unsigned long flags;
1444 	unsigned long avail;
1445 	unsigned long blocks = dwords_to_blocks(dw_len);
1446 	u32 fill_wrap;
1447 	int trycount = 0;
1448 	u32 head, next;
1449 
1450 	spin_lock_irqsave(&sc->alloc_lock, flags);
1451 	if (!(sc->flags & SCF_ENABLED)) {
1452 		spin_unlock_irqrestore(&sc->alloc_lock, flags);
1453 		goto done;
1454 	}
1455 
1456 retry:
1457 	avail = (unsigned long)sc->credits - (sc->fill - sc->alloc_free);
1458 	if (blocks > avail) {
1459 		/* not enough room */
1460 		if (unlikely(trycount))	{ /* already tried to get more room */
1461 			spin_unlock_irqrestore(&sc->alloc_lock, flags);
1462 			goto done;
1463 		}
1464 		/* copy from receiver cache line and recalculate */
1465 		sc->alloc_free = READ_ONCE(sc->free);
1466 		avail =
1467 			(unsigned long)sc->credits -
1468 			(sc->fill - sc->alloc_free);
1469 		if (blocks > avail) {
1470 			/* still no room, actively update */
1471 			sc_release_update(sc);
1472 			sc->alloc_free = READ_ONCE(sc->free);
1473 			trycount++;
1474 			goto retry;
1475 		}
1476 	}
1477 
1478 	/* there is enough room */
1479 
1480 	preempt_disable();
1481 	this_cpu_inc(*sc->buffers_allocated);
1482 
1483 	/* read this once */
1484 	head = sc->sr_head;
1485 
1486 	/* "allocate" the buffer */
1487 	sc->fill += blocks;
1488 	fill_wrap = sc->fill_wrap;
1489 	sc->fill_wrap += blocks;
1490 	if (sc->fill_wrap >= sc->credits)
1491 		sc->fill_wrap = sc->fill_wrap - sc->credits;
1492 
1493 	/*
1494 	 * Fill the parts that the releaser looks at before moving the head.
1495 	 * The only necessary piece is the sent_at field.  The credits
1496 	 * we have just allocated cannot have been returned yet, so the
1497 	 * cb and arg will not be looked at for a "while".  Put them
1498 	 * on this side of the memory barrier anyway.
1499 	 */
1500 	pbuf = &sc->sr[head].pbuf;
1501 	pbuf->sent_at = sc->fill;
1502 	pbuf->cb = cb;
1503 	pbuf->arg = arg;
1504 	pbuf->sc = sc;	/* could be filled in at sc->sr init time */
1505 	/* make sure this is in memory before updating the head */
1506 
1507 	/* calculate next head index, do not store */
1508 	next = head + 1;
1509 	if (next >= sc->sr_size)
1510 		next = 0;
1511 	/*
1512 	 * update the head - must be last! - the releaser can look at fields
1513 	 * in pbuf once we move the head
1514 	 */
1515 	smp_wmb();
1516 	sc->sr_head = next;
1517 	spin_unlock_irqrestore(&sc->alloc_lock, flags);
1518 
1519 	/* finish filling in the buffer outside the lock */
1520 	pbuf->start = sc->base_addr + fill_wrap * PIO_BLOCK_SIZE;
1521 	pbuf->end = sc->base_addr + sc->size;
1522 	pbuf->qw_written = 0;
1523 	pbuf->carry_bytes = 0;
1524 	pbuf->carry.val64 = 0;
1525 done:
1526 	return pbuf;
1527 }
1528 
1529 /*
1530  * There are at least two entities that can turn on credit return
1531  * interrupts and they can overlap.  Avoid problems by implementing
1532  * a count scheme that is enforced by a lock.  The lock is needed because
1533  * the count and CSR write must be paired.
1534  */
1535 
1536 /*
1537  * Start credit return interrupts.  This is managed by a count.  If already
1538  * on, just increment the count.
1539  */
sc_add_credit_return_intr(struct send_context * sc)1540 void sc_add_credit_return_intr(struct send_context *sc)
1541 {
1542 	unsigned long flags;
1543 
1544 	/* lock must surround both the count change and the CSR update */
1545 	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
1546 	if (sc->credit_intr_count == 0) {
1547 		sc->credit_ctrl |= SC(CREDIT_CTRL_CREDIT_INTR_SMASK);
1548 		write_kctxt_csr(sc->dd, sc->hw_context,
1549 				SC(CREDIT_CTRL), sc->credit_ctrl);
1550 	}
1551 	sc->credit_intr_count++;
1552 	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
1553 }
1554 
1555 /*
1556  * Stop credit return interrupts.  This is managed by a count.  Decrement the
1557  * count, if the last user, then turn the credit interrupts off.
1558  */
sc_del_credit_return_intr(struct send_context * sc)1559 void sc_del_credit_return_intr(struct send_context *sc)
1560 {
1561 	unsigned long flags;
1562 
1563 	WARN_ON(sc->credit_intr_count == 0);
1564 
1565 	/* lock must surround both the count change and the CSR update */
1566 	spin_lock_irqsave(&sc->credit_ctrl_lock, flags);
1567 	sc->credit_intr_count--;
1568 	if (sc->credit_intr_count == 0) {
1569 		sc->credit_ctrl &= ~SC(CREDIT_CTRL_CREDIT_INTR_SMASK);
1570 		write_kctxt_csr(sc->dd, sc->hw_context,
1571 				SC(CREDIT_CTRL), sc->credit_ctrl);
1572 	}
1573 	spin_unlock_irqrestore(&sc->credit_ctrl_lock, flags);
1574 }
1575 
1576 /*
1577  * The caller must be careful when calling this.  All needint calls
1578  * must be paired with !needint.
1579  */
hfi1_sc_wantpiobuf_intr(struct send_context * sc,u32 needint)1580 void hfi1_sc_wantpiobuf_intr(struct send_context *sc, u32 needint)
1581 {
1582 	if (needint)
1583 		sc_add_credit_return_intr(sc);
1584 	else
1585 		sc_del_credit_return_intr(sc);
1586 	trace_hfi1_wantpiointr(sc, needint, sc->credit_ctrl);
1587 	if (needint) {
1588 		mmiowb();
1589 		sc_return_credits(sc);
1590 	}
1591 }
1592 
1593 /**
1594  * sc_piobufavail - callback when a PIO buffer is available
1595  * @sc: the send context
1596  *
1597  * This is called from the interrupt handler when a PIO buffer is
1598  * available after hfi1_verbs_send() returned an error that no buffers were
1599  * available. Disable the interrupt if there are no more QPs waiting.
1600  */
sc_piobufavail(struct send_context * sc)1601 static void sc_piobufavail(struct send_context *sc)
1602 {
1603 	struct hfi1_devdata *dd = sc->dd;
1604 	struct hfi1_ibdev *dev = &dd->verbs_dev;
1605 	struct list_head *list;
1606 	struct rvt_qp *qps[PIO_WAIT_BATCH_SIZE];
1607 	struct rvt_qp *qp;
1608 	struct hfi1_qp_priv *priv;
1609 	unsigned long flags;
1610 	uint i, n = 0, max_idx = 0;
1611 	u8 max_starved_cnt = 0;
1612 
1613 	if (dd->send_contexts[sc->sw_index].type != SC_KERNEL &&
1614 	    dd->send_contexts[sc->sw_index].type != SC_VL15)
1615 		return;
1616 	list = &sc->piowait;
1617 	/*
1618 	 * Note: checking that the piowait list is empty and clearing
1619 	 * the buffer available interrupt needs to be atomic or we
1620 	 * could end up with QPs on the wait list with the interrupt
1621 	 * disabled.
1622 	 */
1623 	write_seqlock_irqsave(&dev->iowait_lock, flags);
1624 	while (!list_empty(list)) {
1625 		struct iowait *wait;
1626 
1627 		if (n == ARRAY_SIZE(qps))
1628 			break;
1629 		wait = list_first_entry(list, struct iowait, list);
1630 		qp = iowait_to_qp(wait);
1631 		priv = qp->priv;
1632 		list_del_init(&priv->s_iowait.list);
1633 		priv->s_iowait.lock = NULL;
1634 		iowait_starve_find_max(wait, &max_starved_cnt, n, &max_idx);
1635 		/* refcount held until actual wake up */
1636 		qps[n++] = qp;
1637 	}
1638 	/*
1639 	 * If there had been waiters and there are more
1640 	 * insure that we redo the force to avoid a potential hang.
1641 	 */
1642 	if (n) {
1643 		hfi1_sc_wantpiobuf_intr(sc, 0);
1644 		if (!list_empty(list))
1645 			hfi1_sc_wantpiobuf_intr(sc, 1);
1646 	}
1647 	write_sequnlock_irqrestore(&dev->iowait_lock, flags);
1648 
1649 	/* Wake up the most starved one first */
1650 	if (n)
1651 		hfi1_qp_wakeup(qps[max_idx],
1652 			       RVT_S_WAIT_PIO | HFI1_S_WAIT_PIO_DRAIN);
1653 	for (i = 0; i < n; i++)
1654 		if (i != max_idx)
1655 			hfi1_qp_wakeup(qps[i],
1656 				       RVT_S_WAIT_PIO | HFI1_S_WAIT_PIO_DRAIN);
1657 }
1658 
1659 /* translate a send credit update to a bit code of reasons */
fill_code(u64 hw_free)1660 static inline int fill_code(u64 hw_free)
1661 {
1662 	int code = 0;
1663 
1664 	if (hw_free & CR_STATUS_SMASK)
1665 		code |= PRC_STATUS_ERR;
1666 	if (hw_free & CR_CREDIT_RETURN_DUE_TO_PBC_SMASK)
1667 		code |= PRC_PBC;
1668 	if (hw_free & CR_CREDIT_RETURN_DUE_TO_THRESHOLD_SMASK)
1669 		code |= PRC_THRESHOLD;
1670 	if (hw_free & CR_CREDIT_RETURN_DUE_TO_ERR_SMASK)
1671 		code |= PRC_FILL_ERR;
1672 	if (hw_free & CR_CREDIT_RETURN_DUE_TO_FORCE_SMASK)
1673 		code |= PRC_SC_DISABLE;
1674 	return code;
1675 }
1676 
1677 /* use the jiffies compare to get the wrap right */
1678 #define sent_before(a, b) time_before(a, b)	/* a < b */
1679 
1680 /*
1681  * The send context buffer "releaser".
1682  */
sc_release_update(struct send_context * sc)1683 void sc_release_update(struct send_context *sc)
1684 {
1685 	struct pio_buf *pbuf;
1686 	u64 hw_free;
1687 	u32 head, tail;
1688 	unsigned long old_free;
1689 	unsigned long free;
1690 	unsigned long extra;
1691 	unsigned long flags;
1692 	int code;
1693 
1694 	if (!sc)
1695 		return;
1696 
1697 	spin_lock_irqsave(&sc->release_lock, flags);
1698 	/* update free */
1699 	hw_free = le64_to_cpu(*sc->hw_free);		/* volatile read */
1700 	old_free = sc->free;
1701 	extra = (((hw_free & CR_COUNTER_SMASK) >> CR_COUNTER_SHIFT)
1702 			- (old_free & CR_COUNTER_MASK))
1703 				& CR_COUNTER_MASK;
1704 	free = old_free + extra;
1705 	trace_hfi1_piofree(sc, extra);
1706 
1707 	/* call sent buffer callbacks */
1708 	code = -1;				/* code not yet set */
1709 	head = READ_ONCE(sc->sr_head);	/* snapshot the head */
1710 	tail = sc->sr_tail;
1711 	while (head != tail) {
1712 		pbuf = &sc->sr[tail].pbuf;
1713 
1714 		if (sent_before(free, pbuf->sent_at)) {
1715 			/* not sent yet */
1716 			break;
1717 		}
1718 		if (pbuf->cb) {
1719 			if (code < 0) /* fill in code on first user */
1720 				code = fill_code(hw_free);
1721 			(*pbuf->cb)(pbuf->arg, code);
1722 		}
1723 
1724 		tail++;
1725 		if (tail >= sc->sr_size)
1726 			tail = 0;
1727 	}
1728 	sc->sr_tail = tail;
1729 	/* make sure tail is updated before free */
1730 	smp_wmb();
1731 	sc->free = free;
1732 	spin_unlock_irqrestore(&sc->release_lock, flags);
1733 	sc_piobufavail(sc);
1734 }
1735 
1736 /*
1737  * Send context group releaser.  Argument is the send context that caused
1738  * the interrupt.  Called from the send context interrupt handler.
1739  *
1740  * Call release on all contexts in the group.
1741  *
1742  * This routine takes the sc_lock without an irqsave because it is only
1743  * called from an interrupt handler.  Adjust if that changes.
1744  */
sc_group_release_update(struct hfi1_devdata * dd,u32 hw_context)1745 void sc_group_release_update(struct hfi1_devdata *dd, u32 hw_context)
1746 {
1747 	struct send_context *sc;
1748 	u32 sw_index;
1749 	u32 gc, gc_end;
1750 
1751 	spin_lock(&dd->sc_lock);
1752 	sw_index = dd->hw_to_sw[hw_context];
1753 	if (unlikely(sw_index >= dd->num_send_contexts)) {
1754 		dd_dev_err(dd, "%s: invalid hw (%u) to sw (%u) mapping\n",
1755 			   __func__, hw_context, sw_index);
1756 		goto done;
1757 	}
1758 	sc = dd->send_contexts[sw_index].sc;
1759 	if (unlikely(!sc))
1760 		goto done;
1761 
1762 	gc = group_context(hw_context, sc->group);
1763 	gc_end = gc + group_size(sc->group);
1764 	for (; gc < gc_end; gc++) {
1765 		sw_index = dd->hw_to_sw[gc];
1766 		if (unlikely(sw_index >= dd->num_send_contexts)) {
1767 			dd_dev_err(dd,
1768 				   "%s: invalid hw (%u) to sw (%u) mapping\n",
1769 				   __func__, hw_context, sw_index);
1770 			continue;
1771 		}
1772 		sc_release_update(dd->send_contexts[sw_index].sc);
1773 	}
1774 done:
1775 	spin_unlock(&dd->sc_lock);
1776 }
1777 
1778 /*
1779  * pio_select_send_context_vl() - select send context
1780  * @dd: devdata
1781  * @selector: a spreading factor
1782  * @vl: this vl
1783  *
1784  * This function returns a send context based on the selector and a vl.
1785  * The mapping fields are protected by RCU
1786  */
pio_select_send_context_vl(struct hfi1_devdata * dd,u32 selector,u8 vl)1787 struct send_context *pio_select_send_context_vl(struct hfi1_devdata *dd,
1788 						u32 selector, u8 vl)
1789 {
1790 	struct pio_vl_map *m;
1791 	struct pio_map_elem *e;
1792 	struct send_context *rval;
1793 
1794 	/*
1795 	 * NOTE This should only happen if SC->VL changed after the initial
1796 	 * checks on the QP/AH
1797 	 * Default will return VL0's send context below
1798 	 */
1799 	if (unlikely(vl >= num_vls)) {
1800 		rval = NULL;
1801 		goto done;
1802 	}
1803 
1804 	rcu_read_lock();
1805 	m = rcu_dereference(dd->pio_map);
1806 	if (unlikely(!m)) {
1807 		rcu_read_unlock();
1808 		return dd->vld[0].sc;
1809 	}
1810 	e = m->map[vl & m->mask];
1811 	rval = e->ksc[selector & e->mask];
1812 	rcu_read_unlock();
1813 
1814 done:
1815 	rval = !rval ? dd->vld[0].sc : rval;
1816 	return rval;
1817 }
1818 
1819 /*
1820  * pio_select_send_context_sc() - select send context
1821  * @dd: devdata
1822  * @selector: a spreading factor
1823  * @sc5: the 5 bit sc
1824  *
1825  * This function returns an send context based on the selector and an sc
1826  */
pio_select_send_context_sc(struct hfi1_devdata * dd,u32 selector,u8 sc5)1827 struct send_context *pio_select_send_context_sc(struct hfi1_devdata *dd,
1828 						u32 selector, u8 sc5)
1829 {
1830 	u8 vl = sc_to_vlt(dd, sc5);
1831 
1832 	return pio_select_send_context_vl(dd, selector, vl);
1833 }
1834 
1835 /*
1836  * Free the indicated map struct
1837  */
pio_map_free(struct pio_vl_map * m)1838 static void pio_map_free(struct pio_vl_map *m)
1839 {
1840 	int i;
1841 
1842 	for (i = 0; m && i < m->actual_vls; i++)
1843 		kfree(m->map[i]);
1844 	kfree(m);
1845 }
1846 
1847 /*
1848  * Handle RCU callback
1849  */
pio_map_rcu_callback(struct rcu_head * list)1850 static void pio_map_rcu_callback(struct rcu_head *list)
1851 {
1852 	struct pio_vl_map *m = container_of(list, struct pio_vl_map, list);
1853 
1854 	pio_map_free(m);
1855 }
1856 
1857 /*
1858  * Set credit return threshold for the kernel send context
1859  */
set_threshold(struct hfi1_devdata * dd,int scontext,int i)1860 static void set_threshold(struct hfi1_devdata *dd, int scontext, int i)
1861 {
1862 	u32 thres;
1863 
1864 	thres = min(sc_percent_to_threshold(dd->kernel_send_context[scontext],
1865 					    50),
1866 		    sc_mtu_to_threshold(dd->kernel_send_context[scontext],
1867 					dd->vld[i].mtu,
1868 					dd->rcd[0]->rcvhdrqentsize));
1869 	sc_set_cr_threshold(dd->kernel_send_context[scontext], thres);
1870 }
1871 
1872 /*
1873  * pio_map_init - called when #vls change
1874  * @dd: hfi1_devdata
1875  * @port: port number
1876  * @num_vls: number of vls
1877  * @vl_scontexts: per vl send context mapping (optional)
1878  *
1879  * This routine changes the mapping based on the number of vls.
1880  *
1881  * vl_scontexts is used to specify a non-uniform vl/send context
1882  * loading. NULL implies auto computing the loading and giving each
1883  * VL an uniform distribution of send contexts per VL.
1884  *
1885  * The auto algorithm computers the sc_per_vl and the number of extra
1886  * send contexts. Any extra send contexts are added from the last VL
1887  * on down
1888  *
1889  * rcu locking is used here to control access to the mapping fields.
1890  *
1891  * If either the num_vls or num_send_contexts are non-power of 2, the
1892  * array sizes in the struct pio_vl_map and the struct pio_map_elem are
1893  * rounded up to the next highest power of 2 and the first entry is
1894  * reused in a round robin fashion.
1895  *
1896  * If an error occurs the map change is not done and the mapping is not
1897  * chaged.
1898  *
1899  */
pio_map_init(struct hfi1_devdata * dd,u8 port,u8 num_vls,u8 * vl_scontexts)1900 int pio_map_init(struct hfi1_devdata *dd, u8 port, u8 num_vls, u8 *vl_scontexts)
1901 {
1902 	int i, j;
1903 	int extra, sc_per_vl;
1904 	int scontext = 1;
1905 	int num_kernel_send_contexts = 0;
1906 	u8 lvl_scontexts[OPA_MAX_VLS];
1907 	struct pio_vl_map *oldmap, *newmap;
1908 
1909 	if (!vl_scontexts) {
1910 		for (i = 0; i < dd->num_send_contexts; i++)
1911 			if (dd->send_contexts[i].type == SC_KERNEL)
1912 				num_kernel_send_contexts++;
1913 		/* truncate divide */
1914 		sc_per_vl = num_kernel_send_contexts / num_vls;
1915 		/* extras */
1916 		extra = num_kernel_send_contexts % num_vls;
1917 		vl_scontexts = lvl_scontexts;
1918 		/* add extras from last vl down */
1919 		for (i = num_vls - 1; i >= 0; i--, extra--)
1920 			vl_scontexts[i] = sc_per_vl + (extra > 0 ? 1 : 0);
1921 	}
1922 	/* build new map */
1923 	newmap = kzalloc(sizeof(*newmap) +
1924 			 roundup_pow_of_two(num_vls) *
1925 			 sizeof(struct pio_map_elem *),
1926 			 GFP_KERNEL);
1927 	if (!newmap)
1928 		goto bail;
1929 	newmap->actual_vls = num_vls;
1930 	newmap->vls = roundup_pow_of_two(num_vls);
1931 	newmap->mask = (1 << ilog2(newmap->vls)) - 1;
1932 	for (i = 0; i < newmap->vls; i++) {
1933 		/* save for wrap around */
1934 		int first_scontext = scontext;
1935 
1936 		if (i < newmap->actual_vls) {
1937 			int sz = roundup_pow_of_two(vl_scontexts[i]);
1938 
1939 			/* only allocate once */
1940 			newmap->map[i] = kzalloc(sizeof(*newmap->map[i]) +
1941 						 sz * sizeof(struct
1942 							     send_context *),
1943 						 GFP_KERNEL);
1944 			if (!newmap->map[i])
1945 				goto bail;
1946 			newmap->map[i]->mask = (1 << ilog2(sz)) - 1;
1947 			/*
1948 			 * assign send contexts and
1949 			 * adjust credit return threshold
1950 			 */
1951 			for (j = 0; j < sz; j++) {
1952 				if (dd->kernel_send_context[scontext]) {
1953 					newmap->map[i]->ksc[j] =
1954 					dd->kernel_send_context[scontext];
1955 					set_threshold(dd, scontext, i);
1956 				}
1957 				if (++scontext >= first_scontext +
1958 						  vl_scontexts[i])
1959 					/* wrap back to first send context */
1960 					scontext = first_scontext;
1961 			}
1962 		} else {
1963 			/* just re-use entry without allocating */
1964 			newmap->map[i] = newmap->map[i % num_vls];
1965 		}
1966 		scontext = first_scontext + vl_scontexts[i];
1967 	}
1968 	/* newmap in hand, save old map */
1969 	spin_lock_irq(&dd->pio_map_lock);
1970 	oldmap = rcu_dereference_protected(dd->pio_map,
1971 					   lockdep_is_held(&dd->pio_map_lock));
1972 
1973 	/* publish newmap */
1974 	rcu_assign_pointer(dd->pio_map, newmap);
1975 
1976 	spin_unlock_irq(&dd->pio_map_lock);
1977 	/* success, free any old map after grace period */
1978 	if (oldmap)
1979 		call_rcu(&oldmap->list, pio_map_rcu_callback);
1980 	return 0;
1981 bail:
1982 	/* free any partial allocation */
1983 	pio_map_free(newmap);
1984 	return -ENOMEM;
1985 }
1986 
free_pio_map(struct hfi1_devdata * dd)1987 void free_pio_map(struct hfi1_devdata *dd)
1988 {
1989 	/* Free PIO map if allocated */
1990 	if (rcu_access_pointer(dd->pio_map)) {
1991 		spin_lock_irq(&dd->pio_map_lock);
1992 		pio_map_free(rcu_access_pointer(dd->pio_map));
1993 		RCU_INIT_POINTER(dd->pio_map, NULL);
1994 		spin_unlock_irq(&dd->pio_map_lock);
1995 		synchronize_rcu();
1996 	}
1997 	kfree(dd->kernel_send_context);
1998 	dd->kernel_send_context = NULL;
1999 }
2000 
init_pervl_scs(struct hfi1_devdata * dd)2001 int init_pervl_scs(struct hfi1_devdata *dd)
2002 {
2003 	int i;
2004 	u64 mask, all_vl_mask = (u64)0x80ff; /* VLs 0-7, 15 */
2005 	u64 data_vls_mask = (u64)0x00ff; /* VLs 0-7 */
2006 	u32 ctxt;
2007 	struct hfi1_pportdata *ppd = dd->pport;
2008 
2009 	dd->vld[15].sc = sc_alloc(dd, SC_VL15,
2010 				  dd->rcd[0]->rcvhdrqentsize, dd->node);
2011 	if (!dd->vld[15].sc)
2012 		return -ENOMEM;
2013 
2014 	hfi1_init_ctxt(dd->vld[15].sc);
2015 	dd->vld[15].mtu = enum_to_mtu(OPA_MTU_2048);
2016 
2017 	dd->kernel_send_context = kcalloc_node(dd->num_send_contexts,
2018 					       sizeof(struct send_context *),
2019 					       GFP_KERNEL, dd->node);
2020 	if (!dd->kernel_send_context)
2021 		goto freesc15;
2022 
2023 	dd->kernel_send_context[0] = dd->vld[15].sc;
2024 
2025 	for (i = 0; i < num_vls; i++) {
2026 		/*
2027 		 * Since this function does not deal with a specific
2028 		 * receive context but we need the RcvHdrQ entry size,
2029 		 * use the size from rcd[0]. It is guaranteed to be
2030 		 * valid at this point and will remain the same for all
2031 		 * receive contexts.
2032 		 */
2033 		dd->vld[i].sc = sc_alloc(dd, SC_KERNEL,
2034 					 dd->rcd[0]->rcvhdrqentsize, dd->node);
2035 		if (!dd->vld[i].sc)
2036 			goto nomem;
2037 		dd->kernel_send_context[i + 1] = dd->vld[i].sc;
2038 		hfi1_init_ctxt(dd->vld[i].sc);
2039 		/* non VL15 start with the max MTU */
2040 		dd->vld[i].mtu = hfi1_max_mtu;
2041 	}
2042 	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++) {
2043 		dd->kernel_send_context[i + 1] =
2044 		sc_alloc(dd, SC_KERNEL, dd->rcd[0]->rcvhdrqentsize, dd->node);
2045 		if (!dd->kernel_send_context[i + 1])
2046 			goto nomem;
2047 		hfi1_init_ctxt(dd->kernel_send_context[i + 1]);
2048 	}
2049 
2050 	sc_enable(dd->vld[15].sc);
2051 	ctxt = dd->vld[15].sc->hw_context;
2052 	mask = all_vl_mask & ~(1LL << 15);
2053 	write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
2054 	dd_dev_info(dd,
2055 		    "Using send context %u(%u) for VL15\n",
2056 		    dd->vld[15].sc->sw_index, ctxt);
2057 
2058 	for (i = 0; i < num_vls; i++) {
2059 		sc_enable(dd->vld[i].sc);
2060 		ctxt = dd->vld[i].sc->hw_context;
2061 		mask = all_vl_mask & ~(data_vls_mask);
2062 		write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
2063 	}
2064 	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++) {
2065 		sc_enable(dd->kernel_send_context[i + 1]);
2066 		ctxt = dd->kernel_send_context[i + 1]->hw_context;
2067 		mask = all_vl_mask & ~(data_vls_mask);
2068 		write_kctxt_csr(dd, ctxt, SC(CHECK_VL), mask);
2069 	}
2070 
2071 	if (pio_map_init(dd, ppd->port - 1, num_vls, NULL))
2072 		goto nomem;
2073 	return 0;
2074 
2075 nomem:
2076 	for (i = 0; i < num_vls; i++) {
2077 		sc_free(dd->vld[i].sc);
2078 		dd->vld[i].sc = NULL;
2079 	}
2080 
2081 	for (i = num_vls; i < INIT_SC_PER_VL * num_vls; i++)
2082 		sc_free(dd->kernel_send_context[i + 1]);
2083 
2084 	kfree(dd->kernel_send_context);
2085 	dd->kernel_send_context = NULL;
2086 
2087 freesc15:
2088 	sc_free(dd->vld[15].sc);
2089 	return -ENOMEM;
2090 }
2091 
init_credit_return(struct hfi1_devdata * dd)2092 int init_credit_return(struct hfi1_devdata *dd)
2093 {
2094 	int ret;
2095 	int i;
2096 
2097 	dd->cr_base = kcalloc(
2098 		node_affinity.num_possible_nodes,
2099 		sizeof(struct credit_return_base),
2100 		GFP_KERNEL);
2101 	if (!dd->cr_base) {
2102 		ret = -ENOMEM;
2103 		goto done;
2104 	}
2105 	for_each_node_with_cpus(i) {
2106 		int bytes = TXE_NUM_CONTEXTS * sizeof(struct credit_return);
2107 
2108 		set_dev_node(&dd->pcidev->dev, i);
2109 		dd->cr_base[i].va = dma_zalloc_coherent(
2110 					&dd->pcidev->dev,
2111 					bytes,
2112 					&dd->cr_base[i].dma,
2113 					GFP_KERNEL);
2114 		if (!dd->cr_base[i].va) {
2115 			set_dev_node(&dd->pcidev->dev, dd->node);
2116 			dd_dev_err(dd,
2117 				   "Unable to allocate credit return DMA range for NUMA %d\n",
2118 				   i);
2119 			ret = -ENOMEM;
2120 			goto done;
2121 		}
2122 	}
2123 	set_dev_node(&dd->pcidev->dev, dd->node);
2124 
2125 	ret = 0;
2126 done:
2127 	return ret;
2128 }
2129 
free_credit_return(struct hfi1_devdata * dd)2130 void free_credit_return(struct hfi1_devdata *dd)
2131 {
2132 	int i;
2133 
2134 	if (!dd->cr_base)
2135 		return;
2136 	for (i = 0; i < node_affinity.num_possible_nodes; i++) {
2137 		if (dd->cr_base[i].va) {
2138 			dma_free_coherent(&dd->pcidev->dev,
2139 					  TXE_NUM_CONTEXTS *
2140 					  sizeof(struct credit_return),
2141 					  dd->cr_base[i].va,
2142 					  dd->cr_base[i].dma);
2143 		}
2144 	}
2145 	kfree(dd->cr_base);
2146 	dd->cr_base = NULL;
2147 }
2148