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/*
* Generic bounce buffer implementation
*
* Copyright (C) 2012 Marek Vasut <marex@denx.de>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 (at your option) 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <malloc.h>
#include <errno.h>
#include <bouncebuf.h>
static int addr_aligned(void *data, size_t len)
{
const ulong align_mask = ARCH_DMA_MINALIGN - 1;
/* Check if start is aligned */
if ((ulong)data & align_mask) {
debug("Unaligned start address %p\n", data);
return 0;
}
data += len;
/* Check if end is aligned */
if ((ulong)data & align_mask) {
debug("Unaligned end address %p\n", data);
return 0;
}
/* Aligned */
return 1;
}
int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags)
{
void *tmp;
size_t alen;
if (addr_aligned(*data, len)) {
*backup = NULL;
return 0;
}
alen = roundup(len, ARCH_DMA_MINALIGN);
tmp = memalign(ARCH_DMA_MINALIGN, alen);
if (!tmp)
return -ENOMEM;
if (flags & GEN_BB_READ)
memcpy(tmp, *data, len);
*backup = *data;
*data = tmp;
return 0;
}
int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags)
{
void *tmp = *data;
/* The buffer was already aligned, since "backup" is NULL. */
if (!*backup)
return 0;
if (flags & GEN_BB_WRITE)
memcpy(*backup, *data, len);
*data = *backup;
free(tmp);
return 0;
}
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