xref: /linux/drivers/net/ipa/ipa_table.c (revision bbcd53c960713507ae764bf81970651b5577b95a)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
4  * Copyright (C) 2018-2021 Linaro Ltd.
5  */
6 
7 #include <linux/types.h>
8 #include <linux/kernel.h>
9 #include <linux/bits.h>
10 #include <linux/bitops.h>
11 #include <linux/bitfield.h>
12 #include <linux/io.h>
13 #include <linux/build_bug.h>
14 #include <linux/device.h>
15 #include <linux/dma-mapping.h>
16 
17 #include "ipa.h"
18 #include "ipa_version.h"
19 #include "ipa_endpoint.h"
20 #include "ipa_table.h"
21 #include "ipa_reg.h"
22 #include "ipa_mem.h"
23 #include "ipa_cmd.h"
24 #include "gsi.h"
25 #include "gsi_trans.h"
26 
27 /**
28  * DOC: IPA Filter and Route Tables
29  *
30  * The IPA has tables defined in its local (IPA-resident) memory that define
31  * filter and routing rules.  An entry in either of these tables is a little
32  * endian 64-bit "slot" that holds the address of a rule definition.  (The
33  * size of these slots is 64 bits regardless of the host DMA address size.)
34  *
35  * Separate tables (both filter and route) used for IPv4 and IPv6.  There
36  * are normally another set of "hashed" filter and route tables, which are
37  * used with a hash of message metadata.  Hashed operation is not supported
38  * by all IPA hardware (IPA v4.2 doesn't support hashed tables).
39  *
40  * Rules can be in local memory or in DRAM (system memory).  The offset of
41  * an object (such as a route or filter table) in IPA-resident memory must
42  * 128-byte aligned.  An object in system memory (such as a route or filter
43  * rule) must be at an 8-byte aligned address.  We currently only place
44  * route or filter rules in system memory.
45  *
46  * A rule consists of a contiguous block of 32-bit values terminated with
47  * 32 zero bits.  A special "zero entry" rule consisting of 64 zero bits
48  * represents "no filtering" or "no routing," and is the reset value for
49  * filter or route table rules.
50  *
51  * Each filter rule is associated with an AP or modem TX endpoint, though
52  * not all TX endpoints support filtering.  The first 64-bit slot in a
53  * filter table is a bitmap indicating which endpoints have entries in
54  * the table.  The low-order bit (bit 0) in this bitmap represents a
55  * special global filter, which applies to all traffic.  This is not
56  * used in the current code.  Bit 1, if set, indicates that there is an
57  * entry (i.e. slot containing a system address referring to a rule) for
58  * endpoint 0 in the table.  Bit 3, if set, indicates there is an entry
59  * for endpoint 2, and so on.  Space is set aside in IPA local memory to
60  * hold as many filter table entries as might be required, but typically
61  * they are not all used.
62  *
63  * The AP initializes all entries in a filter table to refer to a "zero"
64  * entry.  Once initialized the modem and AP update the entries for
65  * endpoints they "own" directly.  Currently the AP does not use the
66  * IPA filtering functionality.
67  *
68  *                    IPA Filter Table
69  *                 ----------------------
70  * endpoint bitmap | 0x0000000000000048 | Bits 3 and 6 set (endpoints 2 and 5)
71  *                 |--------------------|
72  * 1st endpoint    | 0x000123456789abc0 | DMA address for modem endpoint 2 rule
73  *                 |--------------------|
74  * 2nd endpoint    | 0x000123456789abf0 | DMA address for AP endpoint 5 rule
75  *                 |--------------------|
76  * (unused)        |                    | (Unused space in filter table)
77  *                 |--------------------|
78  *                          . . .
79  *                 |--------------------|
80  * (unused)        |                    | (Unused space in filter table)
81  *                 ----------------------
82  *
83  * The set of available route rules is divided about equally between the AP
84  * and modem.  The AP initializes all entries in a route table to refer to
85  * a "zero entry".  Once initialized, the modem and AP are responsible for
86  * updating their own entries.  All entries in a route table are usable,
87  * though the AP currently does not use the IPA routing functionality.
88  *
89  *                    IPA Route Table
90  *                 ----------------------
91  * 1st modem route | 0x0001234500001100 | DMA address for first route rule
92  *                 |--------------------|
93  * 2nd modem route | 0x0001234500001140 | DMA address for second route rule
94  *                 |--------------------|
95  *                          . . .
96  *                 |--------------------|
97  * Last modem route| 0x0001234500002280 | DMA address for Nth route rule
98  *                 |--------------------|
99  * 1st AP route    | 0x0001234500001100 | DMA address for route rule (N+1)
100  *                 |--------------------|
101  * 2nd AP route    | 0x0001234500001140 | DMA address for next route rule
102  *                 |--------------------|
103  *                          . . .
104  *                 |--------------------|
105  * Last AP route   | 0x0001234500002280 | DMA address for last route rule
106  *                 ----------------------
107  */
108 
109 /* Assignment of route table entries to the modem and AP */
110 #define IPA_ROUTE_MODEM_MIN		0
111 #define IPA_ROUTE_MODEM_COUNT		8
112 
113 #define IPA_ROUTE_AP_MIN		IPA_ROUTE_MODEM_COUNT
114 #define IPA_ROUTE_AP_COUNT \
115 		(IPA_ROUTE_COUNT_MAX - IPA_ROUTE_MODEM_COUNT)
116 
117 /* Filter or route rules consist of a set of 32-bit values followed by a
118  * 32-bit all-zero rule list terminator.  The "zero rule" is simply an
119  * all-zero rule followed by the list terminator.
120  */
121 #define IPA_ZERO_RULE_SIZE		(2 * sizeof(__le32))
122 
123 #ifdef IPA_VALIDATE
124 
125 /* Check things that can be validated at build time. */
126 static void ipa_table_validate_build(void)
127 {
128 	/* Filter and route tables contain DMA addresses that refer
129 	 * to filter or route rules.  But the size of a table entry
130 	 * is 64 bits regardless of what the size of an AP DMA address
131 	 * is.  A fixed constant defines the size of an entry, and
132 	 * code in ipa_table_init() uses a pointer to __le64 to
133 	 * initialize tables.
134 	 */
135 	BUILD_BUG_ON(sizeof(dma_addr_t) > sizeof(__le64));
136 
137 	/* A "zero rule" is used to represent no filtering or no routing.
138 	 * It is a 64-bit block of zeroed memory.  Code in ipa_table_init()
139 	 * assumes that it can be written using a pointer to __le64.
140 	 */
141 	BUILD_BUG_ON(IPA_ZERO_RULE_SIZE != sizeof(__le64));
142 
143 	/* Impose a practical limit on the number of routes */
144 	BUILD_BUG_ON(IPA_ROUTE_COUNT_MAX > 32);
145 	/* The modem must be allotted at least one route table entry */
146 	BUILD_BUG_ON(!IPA_ROUTE_MODEM_COUNT);
147 	/* But it can't have more than what is available */
148 	BUILD_BUG_ON(IPA_ROUTE_MODEM_COUNT > IPA_ROUTE_COUNT_MAX);
149 
150 }
151 
152 static bool
153 ipa_table_valid_one(struct ipa *ipa, bool route, bool ipv6, bool hashed)
154 {
155 	struct device *dev = &ipa->pdev->dev;
156 	const struct ipa_mem *mem;
157 	u32 size;
158 
159 	if (route) {
160 		if (ipv6)
161 			mem = hashed ? &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]
162 				     : &ipa->mem[IPA_MEM_V6_ROUTE];
163 		else
164 			mem = hashed ? &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]
165 				     : &ipa->mem[IPA_MEM_V4_ROUTE];
166 		size = IPA_ROUTE_COUNT_MAX * sizeof(__le64);
167 	} else {
168 		if (ipv6)
169 			mem = hashed ? &ipa->mem[IPA_MEM_V6_FILTER_HASHED]
170 				     : &ipa->mem[IPA_MEM_V6_FILTER];
171 		else
172 			mem = hashed ? &ipa->mem[IPA_MEM_V4_FILTER_HASHED]
173 				     : &ipa->mem[IPA_MEM_V4_FILTER];
174 		size = (1 + IPA_FILTER_COUNT_MAX) * sizeof(__le64);
175 	}
176 
177 	if (!ipa_cmd_table_valid(ipa, mem, route, ipv6, hashed))
178 		return false;
179 
180 	/* mem->size >= size is sufficient, but we'll demand more */
181 	if (mem->size == size)
182 		return true;
183 
184 	/* Hashed table regions can be zero size if hashing is not supported */
185 	if (hashed && !mem->size)
186 		return true;
187 
188 	dev_err(dev, "IPv%c %s%s table region size 0x%02x, expected 0x%02x\n",
189 		ipv6 ? '6' : '4', hashed ? "hashed " : "",
190 		route ? "route" : "filter", mem->size, size);
191 
192 	return false;
193 }
194 
195 /* Verify the filter and route table memory regions are the expected size */
196 bool ipa_table_valid(struct ipa *ipa)
197 {
198 	bool valid = true;
199 
200 	valid = valid && ipa_table_valid_one(ipa, false, false, false);
201 	valid = valid && ipa_table_valid_one(ipa, false, false, true);
202 	valid = valid && ipa_table_valid_one(ipa, false, true, false);
203 	valid = valid && ipa_table_valid_one(ipa, false, true, true);
204 	valid = valid && ipa_table_valid_one(ipa, true, false, false);
205 	valid = valid && ipa_table_valid_one(ipa, true, false, true);
206 	valid = valid && ipa_table_valid_one(ipa, true, true, false);
207 	valid = valid && ipa_table_valid_one(ipa, true, true, true);
208 
209 	return valid;
210 }
211 
212 bool ipa_filter_map_valid(struct ipa *ipa, u32 filter_map)
213 {
214 	struct device *dev = &ipa->pdev->dev;
215 	u32 count;
216 
217 	if (!filter_map) {
218 		dev_err(dev, "at least one filtering endpoint is required\n");
219 
220 		return false;
221 	}
222 
223 	count = hweight32(filter_map);
224 	if (count > IPA_FILTER_COUNT_MAX) {
225 		dev_err(dev, "too many filtering endpoints (%u, max %u)\n",
226 			count, IPA_FILTER_COUNT_MAX);
227 
228 		return false;
229 	}
230 
231 	return true;
232 }
233 
234 #else /* !IPA_VALIDATE */
235 static void ipa_table_validate_build(void)
236 
237 {
238 }
239 
240 #endif /* !IPA_VALIDATE */
241 
242 /* Zero entry count means no table, so just return a 0 address */
243 static dma_addr_t ipa_table_addr(struct ipa *ipa, bool filter_mask, u16 count)
244 {
245 	u32 skip;
246 
247 	if (!count)
248 		return 0;
249 
250 /* assert(count <= max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX)); */
251 
252 	/* Skip over the zero rule and possibly the filter mask */
253 	skip = filter_mask ? 1 : 2;
254 
255 	return ipa->table_addr + skip * sizeof(*ipa->table_virt);
256 }
257 
258 static void ipa_table_reset_add(struct gsi_trans *trans, bool filter,
259 				u16 first, u16 count, const struct ipa_mem *mem)
260 {
261 	struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
262 	dma_addr_t addr;
263 	u32 offset;
264 	u16 size;
265 
266 	/* Nothing to do if the table memory regions is empty */
267 	if (!mem->size)
268 		return;
269 
270 	if (filter)
271 		first++;	/* skip over bitmap */
272 
273 	offset = mem->offset + first * sizeof(__le64);
274 	size = count * sizeof(__le64);
275 	addr = ipa_table_addr(ipa, false, count);
276 
277 	ipa_cmd_dma_shared_mem_add(trans, offset, size, addr, true);
278 }
279 
280 /* Reset entries in a single filter table belonging to either the AP or
281  * modem to refer to the zero entry.  The memory region supplied will be
282  * for the IPv4 and IPv6 non-hashed and hashed filter tables.
283  */
284 static int
285 ipa_filter_reset_table(struct ipa *ipa, const struct ipa_mem *mem, bool modem)
286 {
287 	u32 ep_mask = ipa->filter_map;
288 	u32 count = hweight32(ep_mask);
289 	struct gsi_trans *trans;
290 	enum gsi_ee_id ee_id;
291 
292 	if (!mem->size)
293 		return 0;
294 
295 	trans = ipa_cmd_trans_alloc(ipa, count);
296 	if (!trans) {
297 		dev_err(&ipa->pdev->dev,
298 			"no transaction for %s filter reset\n",
299 			modem ? "modem" : "AP");
300 		return -EBUSY;
301 	}
302 
303 	ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
304 	while (ep_mask) {
305 		u32 endpoint_id = __ffs(ep_mask);
306 		struct ipa_endpoint *endpoint;
307 
308 		ep_mask ^= BIT(endpoint_id);
309 
310 		endpoint = &ipa->endpoint[endpoint_id];
311 		if (endpoint->ee_id != ee_id)
312 			continue;
313 
314 		ipa_table_reset_add(trans, true, endpoint_id, 1, mem);
315 	}
316 
317 	gsi_trans_commit_wait(trans);
318 
319 	return 0;
320 }
321 
322 /* Theoretically, each filter table could have more filter slots to
323  * update than the maximum number of commands in a transaction.  So
324  * we do each table separately.
325  */
326 static int ipa_filter_reset(struct ipa *ipa, bool modem)
327 {
328 	int ret;
329 
330 	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER], modem);
331 	if (ret)
332 		return ret;
333 
334 	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER_HASHED],
335 				     modem);
336 	if (ret)
337 		return ret;
338 
339 	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER], modem);
340 	if (ret)
341 		return ret;
342 	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER_HASHED],
343 				     modem);
344 
345 	return ret;
346 }
347 
348 /* The AP routes and modem routes are each contiguous within the
349  * table.  We can update each table with a single command, and we
350  * won't exceed the per-transaction command limit.
351  * */
352 static int ipa_route_reset(struct ipa *ipa, bool modem)
353 {
354 	struct gsi_trans *trans;
355 	u16 first;
356 	u16 count;
357 
358 	trans = ipa_cmd_trans_alloc(ipa, 4);
359 	if (!trans) {
360 		dev_err(&ipa->pdev->dev,
361 			"no transaction for %s route reset\n",
362 			modem ? "modem" : "AP");
363 		return -EBUSY;
364 	}
365 
366 	if (modem) {
367 		first = IPA_ROUTE_MODEM_MIN;
368 		count = IPA_ROUTE_MODEM_COUNT;
369 	} else {
370 		first = IPA_ROUTE_AP_MIN;
371 		count = IPA_ROUTE_AP_COUNT;
372 	}
373 
374 	ipa_table_reset_add(trans, false, first, count,
375 			    &ipa->mem[IPA_MEM_V4_ROUTE]);
376 	ipa_table_reset_add(trans, false, first, count,
377 			    &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]);
378 
379 	ipa_table_reset_add(trans, false, first, count,
380 			    &ipa->mem[IPA_MEM_V6_ROUTE]);
381 	ipa_table_reset_add(trans, false, first, count,
382 			    &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]);
383 
384 	gsi_trans_commit_wait(trans);
385 
386 	return 0;
387 }
388 
389 void ipa_table_reset(struct ipa *ipa, bool modem)
390 {
391 	struct device *dev = &ipa->pdev->dev;
392 	const char *ee_name;
393 	int ret;
394 
395 	ee_name = modem ? "modem" : "AP";
396 
397 	/* Report errors, but reset filter and route tables */
398 	ret = ipa_filter_reset(ipa, modem);
399 	if (ret)
400 		dev_err(dev, "error %d resetting filter table for %s\n",
401 				ret, ee_name);
402 
403 	ret = ipa_route_reset(ipa, modem);
404 	if (ret)
405 		dev_err(dev, "error %d resetting route table for %s\n",
406 				ret, ee_name);
407 }
408 
409 int ipa_table_hash_flush(struct ipa *ipa)
410 {
411 	u32 offset = ipa_reg_filt_rout_hash_flush_offset(ipa->version);
412 	struct gsi_trans *trans;
413 	u32 val;
414 
415 	if (!ipa_table_hash_support(ipa))
416 		return 0;
417 
418 	trans = ipa_cmd_trans_alloc(ipa, 1);
419 	if (!trans) {
420 		dev_err(&ipa->pdev->dev, "no transaction for hash flush\n");
421 		return -EBUSY;
422 	}
423 
424 	val = IPV4_FILTER_HASH_FMASK | IPV6_FILTER_HASH_FMASK;
425 	val |= IPV6_ROUTER_HASH_FMASK | IPV4_ROUTER_HASH_FMASK;
426 
427 	ipa_cmd_register_write_add(trans, offset, val, val, false);
428 
429 	gsi_trans_commit_wait(trans);
430 
431 	return 0;
432 }
433 
434 static void ipa_table_init_add(struct gsi_trans *trans, bool filter,
435 			       enum ipa_cmd_opcode opcode,
436 			       const struct ipa_mem *mem,
437 			       const struct ipa_mem *hash_mem)
438 {
439 	struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
440 	dma_addr_t hash_addr;
441 	dma_addr_t addr;
442 	u16 hash_count;
443 	u16 hash_size;
444 	u16 count;
445 	u16 size;
446 
447 	/* The number of filtering endpoints determines number of entries
448 	 * in the filter table.  The hashed and non-hashed filter table
449 	 * will have the same number of entries.  The size of the route
450 	 * table region determines the number of entries it has.
451 	 */
452 	if (filter) {
453 		count = hweight32(ipa->filter_map);
454 		hash_count = hash_mem->size ? count : 0;
455 	} else {
456 		count = mem->size / sizeof(__le64);
457 		hash_count = hash_mem->size / sizeof(__le64);
458 	}
459 	size = count * sizeof(__le64);
460 	hash_size = hash_count * sizeof(__le64);
461 
462 	addr = ipa_table_addr(ipa, filter, count);
463 	hash_addr = ipa_table_addr(ipa, filter, hash_count);
464 
465 	ipa_cmd_table_init_add(trans, opcode, size, mem->offset, addr,
466 			       hash_size, hash_mem->offset, hash_addr);
467 }
468 
469 int ipa_table_setup(struct ipa *ipa)
470 {
471 	struct gsi_trans *trans;
472 
473 	trans = ipa_cmd_trans_alloc(ipa, 4);
474 	if (!trans) {
475 		dev_err(&ipa->pdev->dev, "no transaction for table setup\n");
476 		return -EBUSY;
477 	}
478 
479 	ipa_table_init_add(trans, false, IPA_CMD_IP_V4_ROUTING_INIT,
480 			   &ipa->mem[IPA_MEM_V4_ROUTE],
481 			   &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]);
482 
483 	ipa_table_init_add(trans, false, IPA_CMD_IP_V6_ROUTING_INIT,
484 			   &ipa->mem[IPA_MEM_V6_ROUTE],
485 			   &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]);
486 
487 	ipa_table_init_add(trans, true, IPA_CMD_IP_V4_FILTER_INIT,
488 			   &ipa->mem[IPA_MEM_V4_FILTER],
489 			   &ipa->mem[IPA_MEM_V4_FILTER_HASHED]);
490 
491 	ipa_table_init_add(trans, true, IPA_CMD_IP_V6_FILTER_INIT,
492 			   &ipa->mem[IPA_MEM_V6_FILTER],
493 			   &ipa->mem[IPA_MEM_V6_FILTER_HASHED]);
494 
495 	gsi_trans_commit_wait(trans);
496 
497 	return 0;
498 }
499 
500 /**
501  * ipa_filter_tuple_zero() - Zero an endpoint's hashed filter tuple
502  * @endpoint:	Endpoint whose filter hash tuple should be zeroed
503  *
504  * Endpoint must be for the AP (not modem) and support filtering. Updates
505  * the filter hash values without changing route ones.
506  */
507 static void ipa_filter_tuple_zero(struct ipa_endpoint *endpoint)
508 {
509 	u32 endpoint_id = endpoint->endpoint_id;
510 	u32 offset;
511 	u32 val;
512 
513 	offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(endpoint_id);
514 
515 	val = ioread32(endpoint->ipa->reg_virt + offset);
516 
517 	/* Zero all filter-related fields, preserving the rest */
518 	u32p_replace_bits(&val, 0, IPA_REG_ENDP_FILTER_HASH_MSK_ALL);
519 
520 	iowrite32(val, endpoint->ipa->reg_virt + offset);
521 }
522 
523 /* Configure a hashed filter table; there is no ipa_filter_deconfig() */
524 static void ipa_filter_config(struct ipa *ipa, bool modem)
525 {
526 	enum gsi_ee_id ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
527 	u32 ep_mask = ipa->filter_map;
528 
529 	if (!ipa_table_hash_support(ipa))
530 		return;
531 
532 	while (ep_mask) {
533 		u32 endpoint_id = __ffs(ep_mask);
534 		struct ipa_endpoint *endpoint;
535 
536 		ep_mask ^= BIT(endpoint_id);
537 
538 		endpoint = &ipa->endpoint[endpoint_id];
539 		if (endpoint->ee_id == ee_id)
540 			ipa_filter_tuple_zero(endpoint);
541 	}
542 }
543 
544 static bool ipa_route_id_modem(u32 route_id)
545 {
546 	return route_id >= IPA_ROUTE_MODEM_MIN &&
547 		route_id <= IPA_ROUTE_MODEM_MIN + IPA_ROUTE_MODEM_COUNT - 1;
548 }
549 
550 /**
551  * ipa_route_tuple_zero() - Zero a hashed route table entry tuple
552  * @ipa:	IPA pointer
553  * @route_id:	Route table entry whose hash tuple should be zeroed
554  *
555  * Updates the route hash values without changing filter ones.
556  */
557 static void ipa_route_tuple_zero(struct ipa *ipa, u32 route_id)
558 {
559 	u32 offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(route_id);
560 	u32 val;
561 
562 	val = ioread32(ipa->reg_virt + offset);
563 
564 	/* Zero all route-related fields, preserving the rest */
565 	u32p_replace_bits(&val, 0, IPA_REG_ENDP_ROUTER_HASH_MSK_ALL);
566 
567 	iowrite32(val, ipa->reg_virt + offset);
568 }
569 
570 /* Configure a hashed route table; there is no ipa_route_deconfig() */
571 static void ipa_route_config(struct ipa *ipa, bool modem)
572 {
573 	u32 route_id;
574 
575 	if (!ipa_table_hash_support(ipa))
576 		return;
577 
578 	for (route_id = 0; route_id < IPA_ROUTE_COUNT_MAX; route_id++)
579 		if (ipa_route_id_modem(route_id) == modem)
580 			ipa_route_tuple_zero(ipa, route_id);
581 }
582 
583 /* Configure a filter and route tables; there is no ipa_table_deconfig() */
584 void ipa_table_config(struct ipa *ipa)
585 {
586 	ipa_filter_config(ipa, false);
587 	ipa_filter_config(ipa, true);
588 	ipa_route_config(ipa, false);
589 	ipa_route_config(ipa, true);
590 }
591 
592 /*
593  * Initialize a coherent DMA allocation containing initialized filter and
594  * route table data.  This is used when initializing or resetting the IPA
595  * filter or route table.
596  *
597  * The first entry in a filter table contains a bitmap indicating which
598  * endpoints contain entries in the table.  In addition to that first entry,
599  * there are at most IPA_FILTER_COUNT_MAX entries that follow.  Filter table
600  * entries are 64 bits wide, and (other than the bitmap) contain the DMA
601  * address of a filter rule.  A "zero rule" indicates no filtering, and
602  * consists of 64 bits of zeroes.  When a filter table is initialized (or
603  * reset) its entries are made to refer to the zero rule.
604  *
605  * Each entry in a route table is the DMA address of a routing rule.  For
606  * routing there is also a 64-bit "zero rule" that means no routing, and
607  * when a route table is initialized or reset, its entries are made to refer
608  * to the zero rule.  The zero rule is shared for route and filter tables.
609  *
610  * Note that the IPA hardware requires a filter or route rule address to be
611  * aligned on a 128 byte boundary.  The coherent DMA buffer we allocate here
612  * has a minimum alignment, and we place the zero rule at the base of that
613  * allocated space.  In ipa_table_init() we verify the minimum DMA allocation
614  * meets our requirement.
615  *
616  *	     +-------------------+
617  *	 --> |     zero rule     |
618  *	/    |-------------------|
619  *	|    |     filter mask   |
620  *	|\   |-------------------|
621  *	| ---- zero rule address | \
622  *	|\   |-------------------|  |
623  *	| ---- zero rule address |  |	IPA_FILTER_COUNT_MAX
624  *	|    |-------------------|   >	or IPA_ROUTE_COUNT_MAX,
625  *	|	      ...	    |	whichever is greater
626  *	 \   |-------------------|  |
627  *	  ---- zero rule address | /
628  *	     +-------------------+
629  */
630 int ipa_table_init(struct ipa *ipa)
631 {
632 	u32 count = max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
633 	struct device *dev = &ipa->pdev->dev;
634 	dma_addr_t addr;
635 	__le64 le_addr;
636 	__le64 *virt;
637 	size_t size;
638 
639 	ipa_table_validate_build();
640 
641 	/* The IPA hardware requires route and filter table rules to be
642 	 * aligned on a 128-byte boundary.  We put the "zero rule" at the
643 	 * base of the table area allocated here.  The DMA address returned
644 	 * by dma_alloc_coherent() is guaranteed to be a power-of-2 number
645 	 * of pages, which satisfies the rule alignment requirement.
646 	 */
647 	size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);
648 	virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
649 	if (!virt)
650 		return -ENOMEM;
651 
652 	ipa->table_virt = virt;
653 	ipa->table_addr = addr;
654 
655 	/* First slot is the zero rule */
656 	*virt++ = 0;
657 
658 	/* Next is the filter table bitmap.  The "soft" bitmap value
659 	 * must be converted to the hardware representation by shifting
660 	 * it left one position.  (Bit 0 repesents global filtering,
661 	 * which is possible but not used.)
662 	 */
663 	*virt++ = cpu_to_le64((u64)ipa->filter_map << 1);
664 
665 	/* All the rest contain the DMA address of the zero rule */
666 	le_addr = cpu_to_le64(addr);
667 	while (count--)
668 		*virt++ = le_addr;
669 
670 	return 0;
671 }
672 
673 void ipa_table_exit(struct ipa *ipa)
674 {
675 	u32 count = max_t(u32, 1 + IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
676 	struct device *dev = &ipa->pdev->dev;
677 	size_t size;
678 
679 	size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);
680 
681 	dma_free_coherent(dev, size, ipa->table_virt, ipa->table_addr);
682 	ipa->table_addr = 0;
683 	ipa->table_virt = NULL;
684 }
685