2007-05-18 16:45:16 +02:00
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/*
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* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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2009-05-01 16:41:06 +02:00
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FILE_LICENCE ( GPL2_OR_LATER );
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2007-05-18 16:45:16 +02:00
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#include <stdint.h>
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2007-07-24 18:11:31 +02:00
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#include <errno.h>
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2010-04-19 21:16:01 +02:00
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#include <ipxe/malloc.h>
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#include <ipxe/iobuf.h>
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2007-05-18 16:45:16 +02:00
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/** @file
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*
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* I/O buffers
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*
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*/
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/**
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* Allocate I/O buffer
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*
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* @v len Required length of buffer
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* @ret iobuf I/O buffer, or NULL if none available
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*
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* The I/O buffer will be physically aligned to a multiple of
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* @c IOBUF_SIZE.
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*/
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struct io_buffer * alloc_iob ( size_t len ) {
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struct io_buffer *iobuf = NULL;
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void *data;
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/* Pad to minimum length */
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if ( len < IOB_ZLEN )
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len = IOB_ZLEN;
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/* Align buffer length */
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len = ( len + __alignof__( *iobuf ) - 1 ) &
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~( __alignof__( *iobuf ) - 1 );
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/* Allocate memory for buffer plus descriptor */
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data = malloc_dma ( len + sizeof ( *iobuf ), IOB_ALIGN );
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if ( ! data )
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return NULL;
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iobuf = ( struct io_buffer * ) ( data + len );
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iobuf->head = iobuf->data = iobuf->tail = data;
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iobuf->end = iobuf;
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return iobuf;
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}
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/**
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* Free I/O buffer
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*
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* @v iobuf I/O buffer
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*/
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void free_iob ( struct io_buffer *iobuf ) {
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if ( iobuf ) {
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assert ( iobuf->head <= iobuf->data );
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assert ( iobuf->data <= iobuf->tail );
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assert ( iobuf->tail <= iobuf->end );
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free_dma ( iobuf->head,
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( iobuf->end - iobuf->head ) + sizeof ( *iobuf ) );
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}
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}
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2007-07-24 18:11:31 +02:00
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/**
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* Ensure I/O buffer has sufficient headroom
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*
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* @v iobuf I/O buffer
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* @v len Required headroom
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*
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* This function currently only checks for the required headroom; it
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* does not reallocate the I/O buffer if required. If we ever have a
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* code path that requires this functionality, it's a fairly trivial
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* change to make.
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*/
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int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len ) {
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if ( iob_headroom ( iobuf ) >= len )
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return 0;
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return -ENOBUFS;
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}
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