1 /* $OpenBSD: dma_alloc.c,v 1.13 2016/09/15 02:00:16 dlg Exp $ */
2
3 /*
4 * Copyright (c) 2010 Theo de Raadt <deraadt@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/param.h>
20 #include <sys/systm.h>
21 #include <sys/pool.h>
22
23 #include <uvm/uvm_extern.h>
24
25 static __inline int dma_alloc_index(size_t size);
26
27 /* Create dma pools from objects sized 2^4 to 2^16 */
28 #define DMA_PAGE_SHIFT 16
29 #define DMA_BUCKET_OFFSET 4
30 static char dmanames[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1][10];
31 struct pool dmapools[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1];
32
33 void
dma_alloc_init(void)34 dma_alloc_init(void)
35 {
36 int i;
37
38 for (i = 0; i < nitems(dmapools); i++) {
39 snprintf(dmanames[i], sizeof(dmanames[0]), "dma%d",
40 1 << (i + DMA_BUCKET_OFFSET));
41 pool_init(&dmapools[i], 1 << (i + DMA_BUCKET_OFFSET), 0,
42 IPL_VM, 0, dmanames[i], NULL);
43 pool_set_constraints(&dmapools[i], &kp_dma_contig);
44 /* XXX need pool_setlowat(&dmapools[i], dmalowat); */
45 }
46 }
47
48 static __inline int
dma_alloc_index(size_t sz)49 dma_alloc_index(size_t sz)
50 {
51 int b;
52
53 for (b = 0; b < nitems(dmapools); b++)
54 if (sz <= (1 << (b + DMA_BUCKET_OFFSET)))
55 return (b);
56 #ifdef DEBUG
57 printf("dma_alloc/free: object %zd too large\n", sz);
58 #endif
59 return (-1);
60 }
61
62 void *
dma_alloc(size_t size,int prflags)63 dma_alloc(size_t size, int prflags)
64 {
65 int pi = dma_alloc_index(size);
66
67 if (pi == -1)
68 return (NULL);
69 return pool_get(&dmapools[pi], prflags);
70 }
71
72
73 void
dma_free(void * m,size_t size)74 dma_free(void *m, size_t size)
75 {
76 int pi = dma_alloc_index(size);
77
78 if (pi == -1)
79 return;
80 pool_put(&dmapools[pi], m);
81 }
82