f7fbce07c6
Provide a common function to do the cookie mechanics for completing a DMA descriptor. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Jassi Brar <jassisinghbrar@gmail.com> [imx-sdma.c & mxs-dma.c] Tested-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
/*
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* The contents of this file are private to DMA engine drivers, and is not
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* part of the API to be used by DMA engine users.
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*/
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#ifndef DMAENGINE_H
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#define DMAENGINE_H
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#include <linux/bug.h>
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#include <linux/dmaengine.h>
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/**
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* dma_cookie_assign - assign a DMA engine cookie to the descriptor
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* @tx: descriptor needing cookie
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*
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* Assign a unique non-zero per-channel cookie to the descriptor.
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* Note: caller is expected to hold a lock to prevent concurrency.
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*/
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static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
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{
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struct dma_chan *chan = tx->chan;
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dma_cookie_t cookie;
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cookie = chan->cookie + 1;
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if (cookie < DMA_MIN_COOKIE)
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cookie = DMA_MIN_COOKIE;
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tx->cookie = chan->cookie = cookie;
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return cookie;
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}
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/**
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* dma_cookie_complete - complete a descriptor
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* @tx: descriptor to complete
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*
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* Mark this descriptor complete by updating the channels completed
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* cookie marker. Zero the descriptors cookie to prevent accidental
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* repeated completions.
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*
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* Note: caller is expected to hold a lock to prevent concurrency.
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*/
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static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
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{
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BUG_ON(tx->cookie < DMA_MIN_COOKIE);
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tx->chan->completed_cookie = tx->cookie;
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tx->cookie = 0;
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}
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#endif
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