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
25static __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
30static char dmanames[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1][10];
31struct pool dmapools[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1];
32
33void
34dma_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
48static __inline int
49dma_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
62void *
63dma_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
73void
74dma_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