mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-14 00:47:26 +00:00
1a4596601f
Signed-off-by: Wolfgang Denk <wd@denx.de> [trini: Fixup common/cmd_io.c] Signed-off-by: Tom Rini <trini@ti.com>
72 lines
2.4 KiB
C
72 lines
2.4 KiB
C
/*
|
|
* Generic bounce buffer implementation
|
|
*
|
|
* Copyright (C) 2012 Marek Vasut <marex@denx.de>
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
#ifndef __INCLUDE_BOUNCEBUF_H__
|
|
#define __INCLUDE_BOUNCEBUF_H__
|
|
|
|
#include <linux/types.h>
|
|
|
|
/*
|
|
* GEN_BB_READ -- Data are read from the buffer eg. by DMA hardware.
|
|
* The source buffer is copied into the bounce buffer (if unaligned, otherwise
|
|
* the source buffer is used directly) upon start() call, then the operation
|
|
* requiring the aligned transfer happens, then the bounce buffer is lost upon
|
|
* stop() call.
|
|
*/
|
|
#define GEN_BB_READ (1 << 0)
|
|
/*
|
|
* GEN_BB_WRITE -- Data are written into the buffer eg. by DMA hardware.
|
|
* The source buffer starts in an undefined state upon start() call, then the
|
|
* operation requiring the aligned transfer happens, then the bounce buffer is
|
|
* copied into the destination buffer (if unaligned, otherwise destination
|
|
* buffer is used directly) upon stop() call.
|
|
*/
|
|
#define GEN_BB_WRITE (1 << 1)
|
|
/*
|
|
* GEN_BB_RW -- Data are read and written into the buffer eg. by DMA hardware.
|
|
* The source buffer is copied into the bounce buffer (if unaligned, otherwise
|
|
* the source buffer is used directly) upon start() call, then the operation
|
|
* requiring the aligned transfer happens, then the bounce buffer is copied
|
|
* into the destination buffer (if unaligned, otherwise destination buffer is
|
|
* used directly) upon stop() call.
|
|
*/
|
|
#define GEN_BB_RW (GEN_BB_READ | GEN_BB_WRITE)
|
|
|
|
struct bounce_buffer {
|
|
/* Copy of data parameter passed to start() */
|
|
void *user_buffer;
|
|
/*
|
|
* DMA-aligned buffer. This field is always set to the value that
|
|
* should be used for DMA; either equal to .user_buffer, or to a
|
|
* freshly allocated aligned buffer.
|
|
*/
|
|
void *bounce_buffer;
|
|
/* Copy of len parameter passed to start() */
|
|
size_t len;
|
|
/* DMA-aligned buffer length */
|
|
size_t len_aligned;
|
|
/* Copy of flags parameter passed to start() */
|
|
unsigned int flags;
|
|
};
|
|
|
|
/**
|
|
* bounce_buffer_start() -- Start the bounce buffer session
|
|
* state: stores state passed between bounce_buffer_{start,stop}
|
|
* data: pointer to buffer to be aligned
|
|
* len: length of the buffer
|
|
* flags: flags describing the transaction, see above.
|
|
*/
|
|
int bounce_buffer_start(struct bounce_buffer *state, void *data,
|
|
size_t len, unsigned int flags);
|
|
/**
|
|
* bounce_buffer_stop() -- Finish the bounce buffer session
|
|
* state: stores state passed between bounce_buffer_{start,stop}
|
|
*/
|
|
int bounce_buffer_stop(struct bounce_buffer *state);
|
|
|
|
#endif
|