1// SPDX-License-Identifier: GPL-2.0
2
3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
4 * Copyright (C) 2018-2020 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_AP_MIN		IPA_ROUTE_MODEM_COUNT
112#define IPA_ROUTE_AP_COUNT \
113		(IPA_ROUTE_COUNT_MAX - IPA_ROUTE_MODEM_COUNT)
114
115/* Filter or route rules consist of a set of 32-bit values followed by a
116 * 32-bit all-zero rule list terminator.  The "zero rule" is simply an
117 * all-zero rule followed by the list terminator.
118 */
119#define IPA_ZERO_RULE_SIZE		(2 * sizeof(__le32))
120
121#ifdef IPA_VALIDATE
122
123/* Check things that can be validated at build time. */
124static void ipa_table_validate_build(void)
125{
126	/* Filter and route tables contain DMA addresses that refer
127	 * to filter or route rules.  But the size of a table entry
128	 * is 64 bits regardless of what the size of an AP DMA address
129	 * is.  A fixed constant defines the size of an entry, and
130	 * code in ipa_table_init() uses a pointer to __le64 to
131	 * initialize tables.
132	 */
133	BUILD_BUG_ON(sizeof(dma_addr_t) > sizeof(__le64));
134
135	/* A "zero rule" is used to represent no filtering or no routing.
136	 * It is a 64-bit block of zeroed memory.  Code in ipa_table_init()
137	 * assumes that it can be written using a pointer to __le64.
138	 */
139	BUILD_BUG_ON(IPA_ZERO_RULE_SIZE != sizeof(__le64));
140
141	/* Impose a practical limit on the number of routes */
142	BUILD_BUG_ON(IPA_ROUTE_COUNT_MAX > 32);
143	/* The modem must be allotted at least one route table entry */
144	BUILD_BUG_ON(!IPA_ROUTE_MODEM_COUNT);
145	/* But it can't have more than what is available */
146	BUILD_BUG_ON(IPA_ROUTE_MODEM_COUNT > IPA_ROUTE_COUNT_MAX);
147
148}
149
150static bool
151ipa_table_valid_one(struct ipa *ipa, bool route, bool ipv6, bool hashed)
152{
153	struct device *dev = &ipa->pdev->dev;
154	const struct ipa_mem *mem;
155	u32 size;
156
157	if (route) {
158		if (ipv6)
159			mem = hashed ? &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]
160				     : &ipa->mem[IPA_MEM_V6_ROUTE];
161		else
162			mem = hashed ? &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]
163				     : &ipa->mem[IPA_MEM_V4_ROUTE];
164		size = IPA_ROUTE_COUNT_MAX * sizeof(__le64);
165	} else {
166		if (ipv6)
167			mem = hashed ? &ipa->mem[IPA_MEM_V6_FILTER_HASHED]
168				     : &ipa->mem[IPA_MEM_V6_FILTER];
169		else
170			mem = hashed ? &ipa->mem[IPA_MEM_V4_FILTER_HASHED]
171				     : &ipa->mem[IPA_MEM_V4_FILTER];
172		size = (1 + IPA_FILTER_COUNT_MAX) * sizeof(__le64);
173	}
174
175	if (!ipa_cmd_table_valid(ipa, mem, route, ipv6, hashed))
176		return false;
177
178	/* mem->size >= size is sufficient, but we'll demand more */
179	if (mem->size == size)
180		return true;
181
182	/* Hashed table regions can be zero size if hashing is not supported */
183	if (hashed && !mem->size)
184		return true;
185
186	dev_err(dev, "IPv%c %s%s table region size 0x%02x, expected 0x%02x\n",
187		ipv6 ? '6' : '4', hashed ? "hashed " : "",
188		route ? "route" : "filter", mem->size, size);
189
190	return false;
191}
192
193/* Verify the filter and route table memory regions are the expected size */
194bool ipa_table_valid(struct ipa *ipa)
195{
196	bool valid = true;
197
198	valid = valid && ipa_table_valid_one(ipa, false, false, false);
199	valid = valid && ipa_table_valid_one(ipa, false, false, true);
200	valid = valid && ipa_table_valid_one(ipa, false, true, false);
201	valid = valid && ipa_table_valid_one(ipa, false, true, true);
202	valid = valid && ipa_table_valid_one(ipa, true, false, false);
203	valid = valid && ipa_table_valid_one(ipa, true, false, true);
204	valid = valid && ipa_table_valid_one(ipa, true, true, false);
205	valid = valid && ipa_table_valid_one(ipa, true, true, true);
206
207	return valid;
208}
209
210bool ipa_filter_map_valid(struct ipa *ipa, u32 filter_map)
211{
212	struct device *dev = &ipa->pdev->dev;
213	u32 count;
214
215	if (!filter_map) {
216		dev_err(dev, "at least one filtering endpoint is required\n");
217
218		return false;
219	}
220
221	count = hweight32(filter_map);
222	if (count > IPA_FILTER_COUNT_MAX) {
223		dev_err(dev, "too many filtering endpoints (%u, max %u)\n",
224			count, IPA_FILTER_COUNT_MAX);
225
226		return false;
227	}
228
229	return true;
230}
231
232#else /* !IPA_VALIDATE */
233static void ipa_table_validate_build(void)
234
235{
236}
237
238#endif /* !IPA_VALIDATE */
239
240/* Zero entry count means no table, so just return a 0 address */
241static dma_addr_t ipa_table_addr(struct ipa *ipa, bool filter_mask, u16 count)
242{
243	u32 skip;
244
245	if (!count)
246		return 0;
247
248/* assert(count <= max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX)); */
249
250	/* Skip over the zero rule and possibly the filter mask */
251	skip = filter_mask ? 1 : 2;
252
253	return ipa->table_addr + skip * sizeof(*ipa->table_virt);
254}
255
256static void ipa_table_reset_add(struct gsi_trans *trans, bool filter,
257				u16 first, u16 count, const struct ipa_mem *mem)
258{
259	struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
260	dma_addr_t addr;
261	u32 offset;
262	u16 size;
263
264	/* Nothing to do if the table memory regions is empty */
265	if (!mem->size)
266		return;
267
268	if (filter)
269		first++;	/* skip over bitmap */
270
271	offset = mem->offset + first * sizeof(__le64);
272	size = count * sizeof(__le64);
273	addr = ipa_table_addr(ipa, false, count);
274
275	ipa_cmd_dma_shared_mem_add(trans, offset, size, addr, true);
276}
277
278/* Reset entries in a single filter table belonging to either the AP or
279 * modem to refer to the zero entry.  The memory region supplied will be
280 * for the IPv4 and IPv6 non-hashed and hashed filter tables.
281 */
282static int
283ipa_filter_reset_table(struct ipa *ipa, const struct ipa_mem *mem, bool modem)
284{
285	u32 ep_mask = ipa->filter_map;
286	u32 count = hweight32(ep_mask);
287	struct gsi_trans *trans;
288	enum gsi_ee_id ee_id;
289
290	if (!mem->size)
291		return 0;
292
293	trans = ipa_cmd_trans_alloc(ipa, count);
294	if (!trans) {
295		dev_err(&ipa->pdev->dev,
296			"no transaction for %s filter reset\n",
297			modem ? "modem" : "AP");
298		return -EBUSY;
299	}
300
301	ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
302	while (ep_mask) {
303		u32 endpoint_id = __ffs(ep_mask);
304		struct ipa_endpoint *endpoint;
305
306		ep_mask ^= BIT(endpoint_id);
307
308		endpoint = &ipa->endpoint[endpoint_id];
309		if (endpoint->ee_id != ee_id)
310			continue;
311
312		ipa_table_reset_add(trans, true, endpoint_id, 1, mem);
313	}
314
315	gsi_trans_commit_wait(trans);
316
317	return 0;
318}
319
320/* Theoretically, each filter table could have more filter slots to
321 * update than the maximum number of commands in a transaction.  So
322 * we do each table separately.
323 */
324static int ipa_filter_reset(struct ipa *ipa, bool modem)
325{
326	int ret;
327
328	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER], modem);
329	if (ret)
330		return ret;
331
332	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER_HASHED],
333				     modem);
334	if (ret)
335		return ret;
336
337	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER], modem);
338	if (ret)
339		return ret;
340	ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER_HASHED],
341				     modem);
342
343	return ret;
344}
345
346/* The AP routes and modem routes are each contiguous within the
347 * table.  We can update each table with a single command, and we
348 * won't exceed the per-transaction command limit.
349 * */
350static int ipa_route_reset(struct ipa *ipa, bool modem)
351{
352	struct gsi_trans *trans;
353	u16 first;
354	u16 count;
355
356	trans = ipa_cmd_trans_alloc(ipa, 4);
357	if (!trans) {
358		dev_err(&ipa->pdev->dev,
359			"no transaction for %s route reset\n",
360			modem ? "modem" : "AP");
361		return -EBUSY;
362	}
363
364	if (modem) {
365		first = IPA_ROUTE_MODEM_MIN;
366		count = IPA_ROUTE_MODEM_COUNT;
367	} else {
368		first = IPA_ROUTE_AP_MIN;
369		count = IPA_ROUTE_AP_COUNT;
370	}
371
372	ipa_table_reset_add(trans, false, first, count,
373			    &ipa->mem[IPA_MEM_V4_ROUTE]);
374	ipa_table_reset_add(trans, false, first, count,
375			    &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]);
376
377	ipa_table_reset_add(trans, false, first, count,
378			    &ipa->mem[IPA_MEM_V6_ROUTE]);
379	ipa_table_reset_add(trans, false, first, count,
380			    &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]);
381
382	gsi_trans_commit_wait(trans);
383
384	return 0;
385}
386
387void ipa_table_reset(struct ipa *ipa, bool modem)
388{
389	struct device *dev = &ipa->pdev->dev;
390	const char *ee_name;
391	int ret;
392
393	ee_name = modem ? "modem" : "AP";
394
395	/* Report errors, but reset filter and route tables */
396	ret = ipa_filter_reset(ipa, modem);
397	if (ret)
398		dev_err(dev, "error %d resetting filter table for %s\n",
399				ret, ee_name);
400
401	ret = ipa_route_reset(ipa, modem);
402	if (ret)
403		dev_err(dev, "error %d resetting route table for %s\n",
404				ret, ee_name);
405}
406
407int ipa_table_hash_flush(struct ipa *ipa)
408{
409	u32 offset = ipa_reg_filt_rout_hash_flush_offset(ipa->version);
410	struct gsi_trans *trans;
411	u32 val;
412
413	/* IPA version 4.2 does not support hashed tables */
414	if (ipa->version == IPA_VERSION_4_2)
415		return 0;
416
417	trans = ipa_cmd_trans_alloc(ipa, 1);
418	if (!trans) {
419		dev_err(&ipa->pdev->dev, "no transaction for hash flush\n");
420		return -EBUSY;
421	}
422
423	val = IPV4_FILTER_HASH_FLUSH | IPV6_FILTER_HASH_FLUSH;
424	val |= IPV6_ROUTER_HASH_FLUSH | IPV4_ROUTER_HASH_FLUSH;
425
426	ipa_cmd_register_write_add(trans, offset, val, val, false);
427
428	gsi_trans_commit_wait(trans);
429
430	return 0;
431}
432
433static void ipa_table_init_add(struct gsi_trans *trans, bool filter,
434			       enum ipa_cmd_opcode opcode,
435			       const struct ipa_mem *mem,
436			       const struct ipa_mem *hash_mem)
437{
438	struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
439	dma_addr_t hash_addr;
440	dma_addr_t addr;
441	u16 hash_count;
442	u16 hash_size;
443	u16 count;
444	u16 size;
445
446	/* The number of filtering endpoints determines number of entries
447	 * in the filter table.  The hashed and non-hashed filter table
448	 * will have the same number of entries.  The size of the route
449	 * table region determines the number of entries it has.
450	 */
451	if (filter) {
452		/* Include one extra "slot" to hold the filter map itself */
453		count = 1 + 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
469int 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
500void ipa_table_teardown(struct ipa *ipa)
501{
502	/* Nothing to do */	/* XXX Maybe reset the tables? */
503}
504
505/**
506 * ipa_filter_tuple_zero() - Zero an endpoint's hashed filter tuple
507 * @endpoint:	Endpoint whose filter hash tuple should be zeroed
508 *
509 * Endpoint must be for the AP (not modem) and support filtering. Updates
510 * the filter hash values without changing route ones.
511 */
512static void ipa_filter_tuple_zero(struct ipa_endpoint *endpoint)
513{
514	u32 endpoint_id = endpoint->endpoint_id;
515	u32 offset;
516	u32 val;
517
518	offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(endpoint_id);
519
520	val = ioread32(endpoint->ipa->reg_virt + offset);
521
522	/* Zero all filter-related fields, preserving the rest */
523	u32p_replace_bits(&val, 0, IPA_REG_ENDP_FILTER_HASH_MSK_ALL);
524
525	iowrite32(val, endpoint->ipa->reg_virt + offset);
526}
527
528static void ipa_filter_config(struct ipa *ipa, bool modem)
529{
530	enum gsi_ee_id ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
531	u32 ep_mask = ipa->filter_map;
532
533	/* IPA version 4.2 has no hashed route tables */
534	if (ipa->version == IPA_VERSION_4_2)
535		return;
536
537	while (ep_mask) {
538		u32 endpoint_id = __ffs(ep_mask);
539		struct ipa_endpoint *endpoint;
540
541		ep_mask ^= BIT(endpoint_id);
542
543		endpoint = &ipa->endpoint[endpoint_id];
544		if (endpoint->ee_id == ee_id)
545			ipa_filter_tuple_zero(endpoint);
546	}
547}
548
549static void ipa_filter_deconfig(struct ipa *ipa, bool modem)
550{
551	/* Nothing to do */
552}
553
554static bool ipa_route_id_modem(u32 route_id)
555{
556	return route_id >= IPA_ROUTE_MODEM_MIN &&
557		route_id <= IPA_ROUTE_MODEM_MIN + IPA_ROUTE_MODEM_COUNT - 1;
558}
559
560/**
561 * ipa_route_tuple_zero() - Zero a hashed route table entry tuple
562 * @ipa:	IPA pointer
563 * @route_id:	Route table entry whose hash tuple should be zeroed
564 *
565 * Updates the route hash values without changing filter ones.
566 */
567static void ipa_route_tuple_zero(struct ipa *ipa, u32 route_id)
568{
569	u32 offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(route_id);
570	u32 val;
571
572	val = ioread32(ipa->reg_virt + offset);
573
574	/* Zero all route-related fields, preserving the rest */
575	u32p_replace_bits(&val, 0, IPA_REG_ENDP_ROUTER_HASH_MSK_ALL);
576
577	iowrite32(val, ipa->reg_virt + offset);
578}
579
580static void ipa_route_config(struct ipa *ipa, bool modem)
581{
582	u32 route_id;
583
584	/* IPA version 4.2 has no hashed route tables */
585	if (ipa->version == IPA_VERSION_4_2)
586		return;
587
588	for (route_id = 0; route_id < IPA_ROUTE_COUNT_MAX; route_id++)
589		if (ipa_route_id_modem(route_id) == modem)
590			ipa_route_tuple_zero(ipa, route_id);
591}
592
593static void ipa_route_deconfig(struct ipa *ipa, bool modem)
594{
595	/* Nothing to do */
596}
597
598void ipa_table_config(struct ipa *ipa)
599{
600	ipa_filter_config(ipa, false);
601	ipa_filter_config(ipa, true);
602	ipa_route_config(ipa, false);
603	ipa_route_config(ipa, true);
604}
605
606void ipa_table_deconfig(struct ipa *ipa)
607{
608	ipa_route_deconfig(ipa, true);
609	ipa_route_deconfig(ipa, false);
610	ipa_filter_deconfig(ipa, true);
611	ipa_filter_deconfig(ipa, false);
612}
613
614/*
615 * Initialize a coherent DMA allocation containing initialized filter and
616 * route table data.  This is used when initializing or resetting the IPA
617 * filter or route table.
618 *
619 * The first entry in a filter table contains a bitmap indicating which
620 * endpoints contain entries in the table.  In addition to that first entry,
621 * there are at most IPA_FILTER_COUNT_MAX entries that follow.  Filter table
622 * entries are 64 bits wide, and (other than the bitmap) contain the DMA
623 * address of a filter rule.  A "zero rule" indicates no filtering, and
624 * consists of 64 bits of zeroes.  When a filter table is initialized (or
625 * reset) its entries are made to refer to the zero rule.
626 *
627 * Each entry in a route table is the DMA address of a routing rule.  For
628 * routing there is also a 64-bit "zero rule" that means no routing, and
629 * when a route table is initialized or reset, its entries are made to refer
630 * to the zero rule.  The zero rule is shared for route and filter tables.
631 *
632 * Note that the IPA hardware requires a filter or route rule address to be
633 * aligned on a 128 byte boundary.  The coherent DMA buffer we allocate here
634 * has a minimum alignment, and we place the zero rule at the base of that
635 * allocated space.  In ipa_table_init() we verify the minimum DMA allocation
636 * meets our requirement.
637 *
638 *	     +-------------------+
639 *	 --> |     zero rule     |
640 *	/    |-------------------|
641 *	|    |     filter mask   |
642 *	|\   |-------------------|
643 *	| ---- zero rule address | \
644 *	|\   |-------------------|  |
645 *	| ---- zero rule address |  |	IPA_FILTER_COUNT_MAX
646 *	|    |-------------------|   >	or IPA_ROUTE_COUNT_MAX,
647 *	|	      ...	    |	whichever is greater
648 *	 \   |-------------------|  |
649 *	  ---- zero rule address | /
650 *	     +-------------------+
651 */
652int ipa_table_init(struct ipa *ipa)
653{
654	u32 count = max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
655	struct device *dev = &ipa->pdev->dev;
656	dma_addr_t addr;
657	__le64 le_addr;
658	__le64 *virt;
659	size_t size;
660
661	ipa_table_validate_build();
662
663	/* The IPA hardware requires route and filter table rules to be
664	 * aligned on a 128-byte boundary.  We put the "zero rule" at the
665	 * base of the table area allocated here.  The DMA address returned
666	 * by dma_alloc_coherent() is guaranteed to be a power-of-2 number
667	 * of pages, which satisfies the rule alignment requirement.
668	 */
669	size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);
670	virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
671	if (!virt)
672		return -ENOMEM;
673
674	ipa->table_virt = virt;
675	ipa->table_addr = addr;
676
677	/* First slot is the zero rule */
678	*virt++ = 0;
679
680	/* Next is the filter table bitmap.  The "soft" bitmap value
681	 * must be converted to the hardware representation by shifting
682	 * it left one position.  (Bit 0 repesents global filtering,
683	 * which is possible but not used.)
684	 */
685	*virt++ = cpu_to_le64((u64)ipa->filter_map << 1);
686
687	/* All the rest contain the DMA address of the zero rule */
688	le_addr = cpu_to_le64(addr);
689	while (count--)
690		*virt++ = le_addr;
691
692	return 0;
693}
694
695void ipa_table_exit(struct ipa *ipa)
696{
697	u32 count = max_t(u32, 1 + IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
698	struct device *dev = &ipa->pdev->dev;
699	size_t size;
700
701	size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);
702
703	dma_free_coherent(dev, size, ipa->table_virt, ipa->table_addr);
704	ipa->table_addr = 0;
705	ipa->table_virt = NULL;
706}
707