1/*	$NetBSD: linux_writecomb.c,v 1.9 2021/12/19 10:47:13 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: linux_writecomb.c,v 1.9 2021/12/19 10:47:13 riastradh Exp $");
34
35#if defined(__i386__) || defined(__x86_64__)
36#define HAS_MTRR 1
37#endif
38
39#if defined(_KERNEL_OPT) && defined(HAS_MTRR)
40#include "opt_mtrr.h"
41#endif
42
43#include <sys/kmem.h>
44#include <sys/mutex.h>
45
46#if defined(MTRR)
47#include <machine/mtrr.h>
48#endif
49
50#include <linux/idr.h>
51#include <linux/io.h>
52
53static struct {
54	kmutex_t	lock;
55	struct idr	idr;
56} linux_writecomb __cacheline_aligned;
57
58int
59linux_writecomb_init(void)
60{
61
62	mutex_init(&linux_writecomb.lock, MUTEX_DEFAULT, IPL_VM);
63	idr_init(&linux_writecomb.idr);
64
65	return 0;
66}
67
68void
69linux_writecomb_fini(void)
70{
71
72	KASSERT(idr_is_empty(&linux_writecomb.idr));
73	idr_destroy(&linux_writecomb.idr);
74	mutex_destroy(&linux_writecomb.lock);
75}
76
77int
78arch_phys_wc_add(unsigned long base, unsigned long size)
79{
80#if defined(MTRR)
81	struct mtrr *mtrr;
82	int n = 1;
83	int id;
84	int ret;
85
86	mtrr = kmem_alloc(sizeof(*mtrr), KM_SLEEP);
87	mtrr->base = base;
88	mtrr->len = size;
89	mtrr->type = MTRR_TYPE_WC;
90	mtrr->flags = MTRR_VALID;
91
92	/* XXX errno NetBSD->Linux */
93	ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
94	if (ret) {
95		KASSERT(n == 0);
96		goto fail0;
97	}
98	KASSERT(n == 1);
99
100	idr_preload(GFP_KERNEL);
101	mutex_spin_enter(&linux_writecomb.lock);
102	id = idr_alloc(&linux_writecomb.idr, mtrr, 0, 0, GFP_NOWAIT);
103	mutex_spin_exit(&linux_writecomb.lock);
104	idr_preload_end();
105	if (id < 0)
106		goto fail1;
107
108	return id;
109
110fail1:	KASSERT(id < 0);
111	mtrr->type = 0;
112	mtrr->flags = 0;
113	/* XXX errno NetBSD->Linux */
114	ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
115	KASSERTMSG(ret == 0, "mtrr_set failed to delete: %d", -ret);
116	KASSERTMSG(n == 1, "mtrr_set returned wrong number: %d", n);
117	ret = id;
118fail0:	KASSERT(ret < 0);
119	kmem_free(mtrr, sizeof(*mtrr));
120	return ret;
121#else
122	return -1;
123#endif
124}
125
126void
127arch_phys_wc_del(int id)
128{
129#if defined(MTRR)
130	struct mtrr *mtrr;
131	int n = 1;
132	int ret __diagused;
133
134	KASSERT(0 <= id);
135
136	mutex_spin_enter(&linux_writecomb.lock);
137	mtrr = idr_find(&linux_writecomb.idr, id);
138	idr_remove(&linux_writecomb.idr, id);
139	mutex_spin_exit(&linux_writecomb.lock);
140
141	if (mtrr != NULL) {
142		mtrr->type = 0;
143		mtrr->flags = 0;
144		/* XXX errno NetBSD->Linux */
145		ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
146		KASSERTMSG(ret == 0, "mtrr_set failed to delete: %d", -ret);
147		KASSERTMSG(n == 1, "mtrr_set returned wrong number: %d", n);
148		kmem_free(mtrr, sizeof(*mtrr));
149	}
150#endif
151}
152
153int
154arch_phys_wc_index(int handle)
155{
156
157	/* XXX Actually implement this...requires changes to our MTRR API.  */
158	return handle;
159}
160
161/* XXX Reserve PAT space on x86.  */
162
163int
164arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size)
165{
166	return 0;
167}
168
169void
170arch_io_free_memtype_wc(resource_size_t start, resource_size_t size)
171{
172}
173