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author | Iru Cai <mytbk920423@gmail.com> | 2019-10-30 14:21:52 +0800 |
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committer | Iru Cai <mytbk920423@gmail.com> | 2019-10-30 14:48:38 +0800 |
commit | ae51f41d14f548d494ac41e0d21137c5a4c3f59c (patch) | |
tree | 6ddb9d1aaa7bd5bad5bbf8497edc2e08ff208d79 /include/bouncebuf.h | |
download | uext4-ae51f41d14f548d494ac41e0d21137c5a4c3f59c.tar.xz |
import the U-Boot code and make it compile
Diffstat (limited to 'include/bouncebuf.h')
-rw-r--r-- | include/bouncebuf.h | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/include/bouncebuf.h b/include/bouncebuf.h new file mode 100644 index 0000000..fd9b0f3 --- /dev/null +++ b/include/bouncebuf.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Generic bounce buffer implementation + * + * Copyright (C) 2012 Marek Vasut <marex@denx.de> + */ + +#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 |