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b660df3c90
Implement common bounce buffer to be used on a less capable hardware. That includes hardware that can not do DMA from any address or such. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: Andy Fleming <afleming@freescale.com> Signed-off-by: Andy Fleming <afleming@freescale.com>
93 lines
2.0 KiB
C
93 lines
2.0 KiB
C
/*
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* Generic bounce buffer implementation
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*
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* Copyright (C) 2012 Marek Vasut <marex@denx.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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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
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <malloc.h>
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#include <errno.h>
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#include <bouncebuf.h>
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static int addr_aligned(void *data, size_t len)
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{
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const ulong align_mask = ARCH_DMA_MINALIGN - 1;
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/* Check if start is aligned */
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if ((ulong)data & align_mask) {
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debug("Unaligned start address %p\n", data);
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return 0;
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}
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data += len;
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/* Check if end is aligned */
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if ((ulong)data & align_mask) {
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debug("Unaligned end address %p\n", data);
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return 0;
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}
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/* Aligned */
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return 1;
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}
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int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags)
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{
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void *tmp;
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size_t alen;
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if (addr_aligned(*data, len)) {
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*backup = NULL;
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return 0;
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}
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alen = roundup(len, ARCH_DMA_MINALIGN);
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tmp = memalign(ARCH_DMA_MINALIGN, alen);
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if (!tmp)
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return -ENOMEM;
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if (flags & GEN_BB_READ)
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memcpy(tmp, *data, len);
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*backup = *data;
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*data = tmp;
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return 0;
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}
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int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags)
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{
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void *tmp = *data;
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/* The buffer was already aligned, since "backup" is NULL. */
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if (!*backup)
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return 0;
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if (flags & GEN_BB_WRITE)
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memcpy(*backup, *data, len);
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*data = *backup;
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free(tmp);
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return 0;
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}
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