146 lines
3.3 KiB
C
146 lines
3.3 KiB
C
/*
|
|
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of the
|
|
* License, or any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
* 02110-1301, USA.
|
|
*/
|
|
|
|
FILE_LICENCE ( GPL2_OR_LATER );
|
|
|
|
#include <stdint.h>
|
|
#include <strings.h>
|
|
#include <errno.h>
|
|
#include <ipxe/malloc.h>
|
|
#include <ipxe/iobuf.h>
|
|
|
|
/** @file
|
|
*
|
|
* I/O buffers
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* Allocate I/O buffer
|
|
*
|
|
* @v len Required length of buffer
|
|
* @ret iobuf I/O buffer, or NULL if none available
|
|
*
|
|
* The I/O buffer will be physically aligned to a multiple of
|
|
* @c IOBUF_SIZE.
|
|
*/
|
|
struct io_buffer * alloc_iob ( size_t len ) {
|
|
struct io_buffer *iobuf;
|
|
size_t align;
|
|
void *data;
|
|
|
|
/* Pad to minimum length */
|
|
if ( len < IOB_ZLEN )
|
|
len = IOB_ZLEN;
|
|
|
|
/* Align buffer length to ensure that struct io_buffer is aligned */
|
|
len = ( len + __alignof__ ( *iobuf ) - 1 ) &
|
|
~( __alignof__ ( *iobuf ) - 1 );
|
|
|
|
/* Align buffer on its own size to avoid potential problems
|
|
* with boundary-crossing DMA.
|
|
*/
|
|
align = ( 1 << fls ( len - 1 ) );
|
|
|
|
/* Allocate buffer plus descriptor as a single unit, unless
|
|
* doing so will push the total size over the alignment
|
|
* boundary.
|
|
*/
|
|
if ( ( len + sizeof ( *iobuf ) ) <= align ) {
|
|
|
|
/* Allocate memory for buffer plus descriptor */
|
|
data = malloc_dma ( len + sizeof ( *iobuf ), align );
|
|
if ( ! data )
|
|
return NULL;
|
|
iobuf = ( data + len );
|
|
|
|
} else {
|
|
|
|
/* Allocate memory for buffer */
|
|
data = malloc_dma ( len, align );
|
|
if ( ! data )
|
|
return NULL;
|
|
|
|
/* Allocate memory for descriptor */
|
|
iobuf = malloc ( sizeof ( *iobuf ) );
|
|
if ( ! iobuf ) {
|
|
free_dma ( data, len );
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* Populate descriptor */
|
|
iobuf->head = iobuf->data = iobuf->tail = data;
|
|
iobuf->end = ( data + len );
|
|
|
|
return iobuf;
|
|
}
|
|
|
|
|
|
/**
|
|
* Free I/O buffer
|
|
*
|
|
* @v iobuf I/O buffer
|
|
*/
|
|
void free_iob ( struct io_buffer *iobuf ) {
|
|
size_t len;
|
|
|
|
/* Allow free_iob(NULL) to be valid */
|
|
if ( ! iobuf )
|
|
return;
|
|
|
|
/* Sanity checks */
|
|
assert ( iobuf->head <= iobuf->data );
|
|
assert ( iobuf->data <= iobuf->tail );
|
|
assert ( iobuf->tail <= iobuf->end );
|
|
|
|
/* Free buffer */
|
|
len = ( iobuf->end - iobuf->head );
|
|
if ( iobuf->end == iobuf ) {
|
|
|
|
/* Descriptor is inline */
|
|
free_dma ( iobuf->head, ( len + sizeof ( *iobuf ) ) );
|
|
|
|
} else {
|
|
|
|
/* Descriptor is detached */
|
|
free_dma ( iobuf->head, len );
|
|
free ( iobuf );
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Ensure I/O buffer has sufficient headroom
|
|
*
|
|
* @v iobuf I/O buffer
|
|
* @v len Required headroom
|
|
*
|
|
* This function currently only checks for the required headroom; it
|
|
* does not reallocate the I/O buffer if required. If we ever have a
|
|
* code path that requires this functionality, it's a fairly trivial
|
|
* change to make.
|
|
*/
|
|
int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len ) {
|
|
|
|
if ( iob_headroom ( iobuf ) >= len )
|
|
return 0;
|
|
return -ENOBUFS;
|
|
}
|
|
|