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
53 static struct {
54 kmutex_t lock;
55 struct idr idr;
56 } linux_writecomb __cacheline_aligned;
57
58 int
linux_writecomb_init(void)59 linux_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
68 void
linux_writecomb_fini(void)69 linux_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
77 int
arch_phys_wc_add(unsigned long base,unsigned long size)78 arch_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
110 fail1: 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;
118 fail0: KASSERT(ret < 0);
119 kmem_free(mtrr, sizeof(*mtrr));
120 return ret;
121 #else
122 return -1;
123 #endif
124 }
125
126 void
arch_phys_wc_del(int id)127 arch_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
153 int
arch_phys_wc_index(int handle)154 arch_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
163 int
arch_io_reserve_memtype_wc(resource_size_t start,resource_size_t size)164 arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size)
165 {
166 return 0;
167 }
168
169 void
arch_io_free_memtype_wc(resource_size_t start,resource_size_t size)170 arch_io_free_memtype_wc(resource_size_t start, resource_size_t size)
171 {
172 }
173