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linux_writecomb.c revision 1.6 
      1 /*	$NetBSD: linux_writecomb.c,v 1.6 2018/08/14 14:53:21 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 1.6 2018/08/14 14:53:21 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
     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
     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
     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 	KASSERT(ret == 0);
    116 	KASSERT(n == 1);
    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
    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 		KASSERT(ret == 0);
    147 		KASSERT(n == 1);
    148 		kmem_free(mtrr, sizeof(*mtrr));
    149 	}
    150 #endif
    151 }
    152 
    153 int
    154 phys_wc_to_mtrr_index(int handle)
    155 {
    156 
    157 	/* XXX Actually implement this...requires changes to our MTRR API.  */
    158 	return handle;
    159 }
    160