xref: /freebsd/sys/kern/subr_busdma_bufalloc.c (revision 19261079b74319502c6ffa1249920079f0f69a72)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012 Ian Lepore
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 /*
33  * Buffer allocation support routines for bus_dmamem_alloc implementations.
34  */
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/bus.h>
39 #include <sys/busdma_bufalloc.h>
40 #include <sys/domainset.h>
41 #include <sys/malloc.h>
42 
43 #include <vm/vm.h>
44 #include <vm/vm_extern.h>
45 #include <vm/vm_kern.h>
46 #include <vm/uma.h>
47 
48 /*
49  * We manage buffer zones up to a page in size.  Buffers larger than a page can
50  * be managed by one of the kernel's page-oriented memory allocation routines as
51  * efficiently as what we can do here.  Also, a page is the largest size for
52  * which we can g'tee contiguity when using uma, and contiguity is one of the
53  * requirements we have to fulfill.
54  */
55 #define	MIN_ZONE_BUFSIZE	32
56 #define	MAX_ZONE_BUFSIZE	PAGE_SIZE
57 
58 /*
59  * The static array of 12 bufzones is big enough to handle all the zones for the
60  * smallest supported allocation size of 32 through the largest supported page
61  * size of 64K.  If you up the biggest page size number, up the array size too.
62  * Basically the size of the array needs to be log2(maxsize)-log2(minsize)+1,
63  * but I don't know of an easy way to express that as a compile-time constant.
64  */
65 #if PAGE_SIZE > 65536
66 #error Unsupported page size
67 #endif
68 
69 struct busdma_bufalloc {
70 	bus_size_t		min_size;
71 	size_t			num_zones;
72 	struct busdma_bufzone	buf_zones[12];
73 };
74 
75 busdma_bufalloc_t
76 busdma_bufalloc_create(const char *name, bus_size_t minimum_alignment,
77     uma_alloc alloc_func, uma_free free_func, u_int32_t zcreate_flags)
78 {
79 	struct busdma_bufalloc *ba;
80 	struct busdma_bufzone *bz;
81 	int i;
82 	bus_size_t cursize;
83 
84 	ba = malloc(sizeof(struct busdma_bufalloc), M_DEVBUF,
85 	    M_ZERO | M_WAITOK);
86 
87 	ba->min_size = MAX(MIN_ZONE_BUFSIZE, minimum_alignment);
88 
89 	/*
90 	 * Each uma zone is created with an alignment of size-1, meaning that
91 	 * the alignment is equal to the size (I.E., 64 byte buffers are aligned
92 	 * to 64 byte boundaries, etc).  This allows for a fast efficient test
93 	 * when deciding whether a pool buffer meets the constraints of a given
94 	 * tag used for allocation: the buffer is usable if tag->alignment <=
95 	 * bufzone->size.
96 	 */
97 	for (i = 0, bz = ba->buf_zones, cursize = ba->min_size;
98 	    i < nitems(ba->buf_zones) && cursize <= MAX_ZONE_BUFSIZE;
99 	    ++i, ++bz, cursize <<= 1) {
100 		snprintf(bz->name, sizeof(bz->name), "dma %.10s %ju",
101 		    name, (uintmax_t)cursize);
102 		bz->size = cursize;
103 		bz->umazone = uma_zcreate(bz->name, bz->size,
104 		    NULL, NULL, NULL, NULL, bz->size - 1, zcreate_flags);
105 		if (bz->umazone == NULL) {
106 			busdma_bufalloc_destroy(ba);
107 			return (NULL);
108 		}
109 		if (alloc_func != NULL)
110 			uma_zone_set_allocf(bz->umazone, alloc_func);
111 		if (free_func != NULL)
112 			uma_zone_set_freef(bz->umazone, free_func);
113 		++ba->num_zones;
114 	}
115 
116 	return (ba);
117 }
118 
119 void
120 busdma_bufalloc_destroy(busdma_bufalloc_t ba)
121 {
122 	struct busdma_bufzone *bz;
123 	int i;
124 
125 	if (ba == NULL)
126 		return;
127 
128 	for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) {
129 		uma_zdestroy(bz->umazone);
130 	}
131 
132 	free(ba, M_DEVBUF);
133 }
134 
135 struct busdma_bufzone *
136 busdma_bufalloc_findzone(busdma_bufalloc_t ba, bus_size_t size)
137 {
138 	struct busdma_bufzone *bz;
139 	int i;
140 
141 	if (size > MAX_ZONE_BUFSIZE)
142 		return (NULL);
143 
144 	for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) {
145 		if (bz->size >= size)
146 			return (bz);
147 	}
148 
149 	panic("Didn't find a buffer zone of the right size");
150 }
151 
152 void *
153 busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, vm_size_t size, int domain,
154     uint8_t *pflag, int wait)
155 {
156 
157 #ifdef VM_MEMATTR_UNCACHEABLE
158 	/* Inform UMA that this allocator uses kernel_arena/object. */
159 	*pflag = UMA_SLAB_KERNEL;
160 
161 	return ((void *)kmem_alloc_attr_domainset(DOMAINSET_FIXED(domain), size,
162 	    wait, 0, BUS_SPACE_MAXADDR, VM_MEMATTR_UNCACHEABLE));
163 #else
164 	panic("VM_MEMATTR_UNCACHEABLE unavailable");
165 #endif	/* VM_MEMATTR_UNCACHEABLE */
166 }
167 
168 void
169 busdma_bufalloc_free_uncacheable(void *item, vm_size_t size, uint8_t pflag)
170 {
171 
172 	kmem_free((vm_offset_t)item, size);
173 }
174