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https://github.com/AsahiLinux/u-boot
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
71 lines
2.4 KiB
C
71 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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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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#ifndef __INCLUDE_BOUNCEBUF_H__
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#define __INCLUDE_BOUNCEBUF_H__
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#include <linux/types.h>
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/*
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* GEN_BB_READ -- Data are read from the buffer eg. by DMA hardware.
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* The source buffer is copied into the bounce buffer (if unaligned, otherwise
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* the source buffer is used directly) upon start() call, then the operation
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* requiring the aligned transfer happens, then the bounce buffer is lost upon
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* stop() call.
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*/
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#define GEN_BB_READ (1 << 0)
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/*
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* GEN_BB_WRITE -- Data are written into the buffer eg. by DMA hardware.
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* The source buffer starts in an undefined state upon start() call, then the
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* operation requiring the aligned transfer happens, then the bounce buffer is
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* copied into the destination buffer (if unaligned, otherwise destination
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* buffer is used directly) upon stop() call.
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*/
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#define GEN_BB_WRITE (1 << 1)
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/*
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* GEN_BB_RW -- Data are read and written into the buffer eg. by DMA hardware.
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* The source buffer is copied into the bounce buffer (if unaligned, otherwise
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* the source buffer is used directly) upon start() call, then the operation
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* requiring the aligned transfer happens, then the bounce buffer is copied
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* into the destination buffer (if unaligned, otherwise destination buffer is
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* used directly) upon stop() call.
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*/
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#define GEN_BB_RW (GEN_BB_READ | GEN_BB_WRITE)
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struct bounce_buffer {
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/* Copy of data parameter passed to start() */
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void *user_buffer;
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/*
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* DMA-aligned buffer. This field is always set to the value that
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* should be used for DMA; either equal to .user_buffer, or to a
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* freshly allocated aligned buffer.
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*/
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void *bounce_buffer;
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/* Copy of len parameter passed to start() */
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size_t len;
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/* DMA-aligned buffer length */
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size_t len_aligned;
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/* Copy of flags parameter passed to start() */
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unsigned int flags;
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};
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/**
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* bounce_buffer_start() -- Start the bounce buffer session
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* state: stores state passed between bounce_buffer_{start,stop}
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* data: pointer to buffer to be aligned
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* len: length of the buffer
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* flags: flags describing the transaction, see above.
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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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* bounce_buffer_stop() -- Finish the bounce buffer session
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* state: stores state passed between bounce_buffer_{start,stop}
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*/
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int bounce_buffer_stop(struct bounce_buffer *state);
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#endif
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