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>master
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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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* 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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} |
@ -0,0 +1,87 @@ |
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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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* 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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#ifndef __INCLUDE_BOUNCEBUF_H__ |
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#define __INCLUDE_BOUNCEBUF_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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#ifdef CONFIG_BOUNCE_BUFFER |
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/**
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* bounce_buffer_start() -- Start the bounce buffer session |
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* data: pointer to buffer to be aligned |
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* len: length of the buffer |
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* backup: pointer to backup buffer (the original value is stored here if |
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* needed |
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* flags: flags describing the transaction, see above. |
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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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* bounce_buffer_stop() -- Finish the bounce buffer session |
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* data: pointer to buffer that was aligned |
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* len: length of the buffer |
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* backup: pointer to backup buffer (the original value is stored here if |
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* needed |
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* flags: flags describing the transaction, see above. |
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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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#else |
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static inline int bounce_buffer_start(void **data, size_t len, void **backup, |
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uint8_t flags) |
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{ |
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return 0; |
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} |
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static inline int bounce_buffer_stop(void **data, size_t len, void **backup, |
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uint8_t flags) |
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{ |
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return 0; |
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} |
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#endif |
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#endif |
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