--- /dev/null
+/*
+ * 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 with specified alignment and offset
+ *
+ * @v len Required length of buffer
+ * @v align Physical alignment
+ * @v offset Offset from physical alignment
+ * @ret iobuf I/O buffer, or NULL if none available
+ *
+ * @c align will be rounded up to the nearest power of two.
+ */
+struct io_buffer * alloc_iob_raw ( size_t len, size_t align, size_t offset ) {
+ struct io_buffer *iobuf;
+ void *data;
+
+ /* Align buffer length to ensure that struct io_buffer is aligned */
+ len = ( len + __alignof__ ( *iobuf ) - 1 ) &
+ ~( __alignof__ ( *iobuf ) - 1 );
+
+ /* Round up alignment to the nearest power of two */
+ align = ( 1 << fls ( align - 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_offset ( len + sizeof ( *iobuf ), align,
+ offset );
+ if ( ! data )
+ return NULL;
+ iobuf = ( data + len );
+
+ } else {
+
+ /* Allocate memory for buffer */
+ data = malloc_dma_offset ( len, align, offset );
+ 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;
+}
+
+/**
+ * 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 on its own size (rounded
+ * up to the nearest power of two).
+ */
+struct io_buffer * alloc_iob ( size_t len ) {
+
+ /* Pad to minimum length */
+ if ( len < IOB_ZLEN )
+ len = IOB_ZLEN;
+
+ /* Align buffer on its own size to avoid potential problems
+ * with boundary-crossing DMA.
+ */
+ return alloc_iob_raw ( len, len, 0 );
+}
+
+/**
+ * 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;
+}
+
+/**
+ * Concatenate I/O buffers into a single buffer
+ *
+ * @v list List of I/O buffers
+ * @ret iobuf Concatenated I/O buffer, or NULL on allocation failure
+ *
+ * After a successful concatenation, the list will be empty.
+ */
+struct io_buffer * iob_concatenate ( struct list_head *list ) {
+ struct io_buffer *iobuf;
+ struct io_buffer *tmp;
+ struct io_buffer *concatenated;
+ size_t len = 0;
+
+ /* If the list contains only a single entry, avoid an
+ * unnecessary additional allocation.
+ */
+ if ( list_is_singular ( list ) ) {
+ iobuf = list_first_entry ( list, struct io_buffer, list );
+ INIT_LIST_HEAD ( list );
+ return iobuf;
+ }
+
+ /* Calculate total length */
+ list_for_each_entry ( iobuf, list, list )
+ len += iob_len ( iobuf );
+
+ /* Allocate new I/O buffer */
+ concatenated = alloc_iob_raw ( len, __alignof__ ( *iobuf ), 0 );
+ if ( ! concatenated )
+ return NULL;
+
+ /* Move data to new I/O buffer */
+ list_for_each_entry_safe ( iobuf, tmp, list, list ) {
+ list_del ( &iobuf->list );
+ memcpy ( iob_put ( concatenated, iob_len ( iobuf ) ),
+ iobuf->data, iob_len ( iobuf ) );
+ free_iob ( iobuf );
+ }
+
+ return concatenated;
+}
Code Review / kvmfornfv.git / blobdiff