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https://github.com/brain-hackers/u-boot-brain
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84d35b2863
The current bouncebuf API requires all parameters to be passed to both bounce_buffer_start() and bounce_buffer_stop(). Modify the bouncebuf start function to accept a state structure as a parameter, and only require that state struct to be passed to the stop function. This simplifies usage of the bounce buffer by clients. Don't modify the data pointer, but rather store the temporary buffer in this state struct. The bouncebuf code ensures that client code can always use a single buffer pointer in the state structure, irrespective of whether a bounce buffer actually had to be allocated. Move cache management logic into the bounce buffer code, so that each client doesn't have to duplicate this. I believe there's no need to invalidate the buffer before a DMA operation, since flushing the cache should prevent any write-backs. Update the MXS MMC driver for this change. Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Simon Glass <sjg@chromium.org> Tested-by: Simon Glass <sjg@chromium.org> Signed-off-by: Andy Fleming <afleming@freescale.com>
100 lines
2.6 KiB
C
100 lines
2.6 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(struct bounce_buffer *state)
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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)state->user_buffer & align_mask) {
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debug("Unaligned buffer address %p\n", state->user_buffer);
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return 0;
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}
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/* Check if length is aligned */
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if (state->len != state->len_aligned) {
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debug("Unaligned buffer length %d\n", state->len);
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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(struct bounce_buffer *state, void *data,
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size_t len, unsigned int flags)
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{
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state->user_buffer = data;
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state->bounce_buffer = data;
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state->len = len;
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state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
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state->flags = flags;
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if (!addr_aligned(state)) {
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state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
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state->len_aligned);
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if (!state->bounce_buffer)
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return -ENOMEM;
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if (state->flags & GEN_BB_READ)
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memcpy(state->bounce_buffer, state->user_buffer,
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state->len);
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}
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/*
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* Flush data to RAM so DMA reads can pick it up,
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* and any CPU writebacks don't race with DMA writes
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*/
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flush_dcache_range((unsigned long)state->bounce_buffer,
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(unsigned long)(state->bounce_buffer) +
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state->len_aligned);
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return 0;
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}
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int bounce_buffer_stop(struct bounce_buffer *state)
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{
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if (state->flags & GEN_BB_WRITE) {
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/* Invalidate cache so that CPU can see any newly DMA'd data */
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invalidate_dcache_range((unsigned long)state->bounce_buffer,
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(unsigned long)(state->bounce_buffer) +
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state->len_aligned);
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}
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if (state->bounce_buffer == state->user_buffer)
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return 0;
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if (state->flags & GEN_BB_WRITE)
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memcpy(state->user_buffer, state->bounce_buffer, state->len);
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free(state->bounce_buffer);
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return 0;
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}
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