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1.1 root 1: /*
2: * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
7: * Reserved. This file contains Original Code and/or Modifications of
8: * Original Code as defined in and that are subject to the Apple Public
9: * Source License Version 1.1 (the "License"). You may not use this file
10: * except in compliance with the License. Please obtain a copy of the
11: * License at http://www.apple.com/publicsource and read it before using
12: * this file.
13: *
14: * The Original Code and all software distributed under the License are
15: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
19: * License for the specific language governing rights and limitations
20: * under the License.
21: *
22: * @APPLE_LICENSE_HEADER_END@
23: */
24:
25: /*
26: * Copyright (c) 1992 NeXT Computer, Inc.
27: *
28: * dma_buf.c -- DMA buffer handling.
29: *
30: * HISTORY
31: *
32: * 26 August 1992 ? at NeXT
33: * Created.
34: */
35:
36: #import <mach/mach_types.h>
37:
38: #import <machdep/i386/dma_buf_internal.h>
39: #import <machdep/i386/dma_exported.h>
40:
41: dma_buf_type_t dma_buf_sm, dma_buf_lg;
42:
43: static inline int is_aligned( void *addr, unsigned int alignment )
44: {
45: return (((unsigned int)addr & (alignment - 1)) == 0);
46: }
47: void
48: dma_buf_initialize(
49: void
50: )
51: {
52: int maxbufs = DMA_BUF_LG_LEN / DMA_BUF_SM_LEN + 1;
53: dma_buf_t buf, bufs[maxbufs];
54: int nbufs = 0;
55:
56: dma_buf_sm.create_fcn = dma_buf_sm_create;
57: dma_buf_lg.create_fcn = dma_buf_lg_create;
58:
59: /*
60: * Allocate small buffers until the next buffer
61: * will be on a large-buffer boundary.
62: * This makes assumptions about the way alloc_cnvmem works -- FIXME!
63: */
64: do {
65: if (dma_buf_alloc(&buf, DMA_BUF_SM_LEN) != TRUE)
66: break;
67: bufs[nbufs++] = buf;
68: } while (maxbufs-- &&
69: !is_aligned((char *)buf._ptr+DMA_BUF_SM_LEN, DMA_BUF_LG_LEN));
70: while (nbufs)
71: dma_buf_free(&bufs[(nbufs--) - 1]);
72:
73: /*
74: * Now create one large buffer.
75: */
76: if (dma_buf_alloc(&buf, DMA_BUF_LG_LEN) == TRUE)
77: dma_buf_free(&buf);
78: }
79:
80: boolean_t
81: dma_buf_alloc(
82: dma_buf_t *buf,
83: vm_size_t len
84: )
85: {
86: dma_buf_region_t *ptr;
87: dma_buf_type_t *buft;
88: int s;
89:
90: if (len > DMA_BUF_LG_LEN)
91: return (FALSE);
92: else if (len > DMA_BUF_SM_LEN)
93: buft = &dma_buf_lg;
94: else
95: buft = &dma_buf_sm;
96:
97: s = spldma();
98:
99: if (ptr = buft->free_head) {
100: buft->free_head = ptr->next;
101: buft->free_count--;
102: }
103: else {
104: ptr = (*buft->create_fcn)();
105: if (ptr)
106: buft->total_count++;
107: }
108:
109: splx(s);
110:
111: if (ptr == 0)
112: return (FALSE);
113:
114: buf->_ptr = (void *)ptr;
115: buf->_type = (void *)buft;
116:
117: return (TRUE);
118: }
119:
120: void
121: dma_buf_free(
122: dma_buf_t *buf
123: )
124: {
125: dma_buf_region_t *ptr;
126: dma_buf_type_t *buft;
127: int s;
128:
129: if ((ptr = (dma_buf_region_t *)buf->_ptr) == 0)
130: return;
131:
132: buft = (dma_buf_type_t *)buf->_type;
133:
134: s = spldma();
135:
136: ptr->next = buft->free_head;
137: buft->free_head = ptr;
138: buft->free_count++;
139:
140: splx(s);
141:
142: buf->_ptr = 0;
143: buf->_type = 0;
144: }
145:
146: static
147: dma_buf_region_t *
148: dma_buf_sm_create(
149: void
150: )
151: {
152: caddr_t buf = (caddr_t)alloc_cnvmem(DMA_BUF_SM_LEN, DMA_BUF_SM_LEN);
153: if (buf)
154: bzero(buf,DMA_BUF_SM_LEN);
155: return ((dma_buf_region_t *)buf );
156: }
157:
158: /*
159: * Eventually, this should allocate small buffers until we get
160: * to a large buffer alignment boundary.
161: */
162:
163: static
164: dma_buf_region_t *
165: dma_buf_lg_create(
166: void
167: )
168: {
169: caddr_t buf = (caddr_t)alloc_cnvmem(DMA_BUF_LG_LEN, DMA_BUF_LG_LEN);
170: if (buf)
171: bzero(buf,DMA_BUF_LG_LEN);
172: return ((dma_buf_region_t *)buf );
173: }
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