1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <stdint.h>
22 #include <errno.h>
23 #include <gpxe/malloc.h>
24 #include <gpxe/iobuf.h>
25
26 /** @file
27 *
28 * I/O buffers
29 *
30 */
31
32 /**
33 * Allocate I/O buffer
34 *
35 * @v len Required length of buffer
36 * @ret iobuf I/O buffer, or NULL if none available
37 *
38 * The I/O buffer will be physically aligned to a multiple of
39 * @c IOBUF_SIZE.
40 */
alloc_iob(size_t len)41 struct io_buffer * alloc_iob ( size_t len ) {
42 struct io_buffer *iobuf = NULL;
43 void *data;
44
45 /* Pad to minimum length */
46 if ( len < IOB_ZLEN )
47 len = IOB_ZLEN;
48
49 /* Align buffer length */
50 len = ( len + __alignof__( *iobuf ) - 1 ) &
51 ~( __alignof__( *iobuf ) - 1 );
52
53 /* Allocate memory for buffer plus descriptor */
54 data = malloc_dma ( len + sizeof ( *iobuf ), IOB_ALIGN );
55 if ( ! data )
56 return NULL;
57
58 iobuf = ( struct io_buffer * ) ( data + len );
59 iobuf->head = iobuf->data = iobuf->tail = data;
60 iobuf->end = iobuf;
61 return iobuf;
62 }
63
64 /**
65 * Free I/O buffer
66 *
67 * @v iobuf I/O buffer
68 */
free_iob(struct io_buffer * iobuf)69 void free_iob ( struct io_buffer *iobuf ) {
70 if ( iobuf ) {
71 assert ( iobuf->head <= iobuf->data );
72 assert ( iobuf->data <= iobuf->tail );
73 assert ( iobuf->tail <= iobuf->end );
74 free_dma ( iobuf->head,
75 ( iobuf->end - iobuf->head ) + sizeof ( *iobuf ) );
76 }
77 }
78
79 /**
80 * Ensure I/O buffer has sufficient headroom
81 *
82 * @v iobuf I/O buffer
83 * @v len Required headroom
84 *
85 * This function currently only checks for the required headroom; it
86 * does not reallocate the I/O buffer if required. If we ever have a
87 * code path that requires this functionality, it's a fairly trivial
88 * change to make.
89 */
iob_ensure_headroom(struct io_buffer * iobuf,size_t len)90 int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len ) {
91
92 if ( iob_headroom ( iobuf ) >= len )
93 return 0;
94 return -ENOBUFS;
95 }
96
97