2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (c) 2012 Ian Lepore
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8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
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14 * documentation and/or other materials provided with the distribution.
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19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 #include <sys/cdefs.h>
31 * Buffer allocation support routines for bus_dmamem_alloc implementations.
34 #include <sys/param.h>
35 #include <sys/systm.h>
37 #include <sys/busdma_bufalloc.h>
38 #include <sys/domainset.h>
39 #include <sys/malloc.h>
42 #include <vm/vm_extern.h>
43 #include <vm/vm_kern.h>
47 * We manage buffer zones up to a page in size. Buffers larger than a page can
48 * be managed by one of the kernel's page-oriented memory allocation routines as
49 * efficiently as what we can do here. Also, a page is the largest size for
50 * which we can g'tee contiguity when using uma, and contiguity is one of the
51 * requirements we have to fulfill.
53 #define MIN_ZONE_BUFSIZE 32
54 #define MAX_ZONE_BUFSIZE PAGE_SIZE
57 * The static array of 12 bufzones is big enough to handle all the zones for the
58 * smallest supported allocation size of 32 through the largest supported page
59 * size of 64K. If you up the biggest page size number, up the array size too.
60 * Basically the size of the array needs to be log2(maxsize)-log2(minsize)+1,
61 * but I don't know of an easy way to express that as a compile-time constant.
64 #error Unsupported page size
67 struct busdma_bufalloc {
70 struct busdma_bufzone buf_zones[12];
74 busdma_bufalloc_create(const char *name, bus_size_t minimum_alignment,
75 uma_alloc alloc_func, uma_free free_func, u_int32_t zcreate_flags)
77 struct busdma_bufalloc *ba;
78 struct busdma_bufzone *bz;
82 ba = malloc(sizeof(struct busdma_bufalloc), M_DEVBUF,
85 ba->min_size = MAX(MIN_ZONE_BUFSIZE, minimum_alignment);
88 * Each uma zone is created with an alignment of size-1, meaning that
89 * the alignment is equal to the size (I.E., 64 byte buffers are aligned
90 * to 64 byte boundaries, etc). This allows for a fast efficient test
91 * when deciding whether a pool buffer meets the constraints of a given
92 * tag used for allocation: the buffer is usable if tag->alignment <=
95 for (i = 0, bz = ba->buf_zones, cursize = ba->min_size;
96 i < nitems(ba->buf_zones) && cursize <= MAX_ZONE_BUFSIZE;
97 ++i, ++bz, cursize <<= 1) {
98 snprintf(bz->name, sizeof(bz->name), "dma %.10s %ju",
99 name, (uintmax_t)cursize);
101 bz->umazone = uma_zcreate(bz->name, bz->size,
102 NULL, NULL, NULL, NULL, bz->size - 1, zcreate_flags);
103 if (bz->umazone == NULL) {
104 busdma_bufalloc_destroy(ba);
107 if (alloc_func != NULL)
108 uma_zone_set_allocf(bz->umazone, alloc_func);
109 if (free_func != NULL)
110 uma_zone_set_freef(bz->umazone, free_func);
118 busdma_bufalloc_destroy(busdma_bufalloc_t ba)
120 struct busdma_bufzone *bz;
126 for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) {
127 uma_zdestroy(bz->umazone);
133 struct busdma_bufzone *
134 busdma_bufalloc_findzone(busdma_bufalloc_t ba, bus_size_t size)
136 struct busdma_bufzone *bz;
139 if (size > MAX_ZONE_BUFSIZE)
142 for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) {
143 if (bz->size >= size)
147 panic("Didn't find a buffer zone of the right size");
151 busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, vm_size_t size, int domain,
152 uint8_t *pflag, int wait)
155 #ifdef VM_MEMATTR_UNCACHEABLE
156 /* Inform UMA that this allocator uses kernel_arena/object. */
157 *pflag = UMA_SLAB_KERNEL;
159 return ((void *)kmem_alloc_attr_domainset(DOMAINSET_FIXED(domain), size,
160 wait, 0, BUS_SPACE_MAXADDR, VM_MEMATTR_UNCACHEABLE));
162 panic("VM_MEMATTR_UNCACHEABLE unavailable");
163 #endif /* VM_MEMATTR_UNCACHEABLE */
167 busdma_bufalloc_free_uncacheable(void *item, vm_size_t size, uint8_t pflag)
170 kmem_free((vm_offset_t)item, size);