linux_writecomb.c revision 1.3 
1/*	$NetBSD: linux_writecomb.c,v 1.3 2015/01/01 01:15:43 mrg 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 1.3 2015/01/01 01:15:43 mrg Exp $");
34
35#ifdef _KERNEL_OPT
36#include "opt_mtrr.h"
37#endif
38
39#include <sys/kmem.h>
40#include <sys/mutex.h>
41
42#include <machine/mtrr.h>
43
44#include <linux/idr.h>
45#include <linux/io.h>
46
47static struct {
48	kmutex_t	lock;
49	struct idr	idr;
50} linux_writecomb __cacheline_aligned;
51
52int
53linux_writecomb_init(void)
54{
55
56	mutex_init(&linux_writecomb.lock, MUTEX_DEFAULT, IPL_VM);
57	idr_init(&linux_writecomb.idr);
58
59	return 0;
60}
61
62void
63linux_writecomb_fini(void)
64{
65
66	KASSERT(idr_is_empty(&linux_writecomb.idr));
67	idr_destroy(&linux_writecomb.idr);
68	mutex_destroy(&linux_writecomb.lock);
69}
70
71int
72arch_phys_wc_add(unsigned long base, unsigned long size)
73{
74	struct mtrr *mtrr;
75	int n = 1;
76	int id;
77	int ret;
78
79	mtrr = kmem_alloc(sizeof(*mtrr), KM_SLEEP);
80	mtrr->base = base;
81	mtrr->len = size;
82	mtrr->type = MTRR_TYPE_WC;
83	mtrr->flags = MTRR_VALID;
84
85	/* XXX errno NetBSD->Linux */
86	ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
87	if (ret) {
88		KASSERT(n == 0);
89		goto fail0;
90	}
91	KASSERT(n == 1);
92
93	idr_preload(GFP_KERNEL);
94	mutex_spin_enter(&linux_writecomb.lock);
95	id = idr_alloc(&linux_writecomb.idr, mtrr, 0, 0, GFP_NOWAIT);
96	mutex_spin_exit(&linux_writecomb.lock);
97	idr_preload_end();
98	if (id < 0)
99		goto fail1;
100
101	return id;
102
103fail1:	KASSERT(id < 0);
104	mtrr->type = 0;
105	mtrr->flags = 0;
106	/* XXX errno NetBSD->Linux */
107	ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
108	KASSERT(ret == 0);
109	KASSERT(n == 1);
110	ret = id;
111fail0:	KASSERT(ret < 0);
112	kmem_free(mtrr, sizeof(*mtrr));
113	return ret;
114}
115
116void
117arch_phys_wc_del(int id)
118{
119	struct mtrr *mtrr;
120	int n;
121	int ret __diagused;
122
123	KASSERT(0 <= id);
124
125	mutex_spin_enter(&linux_writecomb.lock);
126	mtrr = idr_find(&linux_writecomb.idr, id);
127	idr_remove(&linux_writecomb.idr, id);
128	mutex_spin_enter(&linux_writecomb.lock);
129
130	if (mtrr != NULL) {
131		mtrr->type = 0;
132		mtrr->flags = 0;
133		/* XXX errno NetBSD->Linux */
134		ret = -mtrr_set(mtrr, &n, NULL, MTRR_GETSET_KERNEL);
135		KASSERT(ret == 0);
136		KASSERT(n == 1);
137		kmem_free(mtrr, sizeof(*mtrr));
138	}
139}
140
141int
142phys_wc_to_mtrr_index(int handle)
143{
144
145	/* XXX Actually implement this...requires changes to our MTRR API.  */
146	return handle;
147}
148