90 lines
2.2 KiB
C
90 lines
2.2 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_init - initialize the cookies for a DMA channel
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* @chan: dma channel to initialize
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*/
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static inline void dma_cookie_init(struct dma_chan *chan)
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{
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chan->cookie = DMA_MIN_COOKIE;
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chan->completed_cookie = DMA_MIN_COOKIE;
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}
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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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/**
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* dma_cookie_status - report cookie status
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* @chan: dma channel
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* @cookie: cookie we are interested in
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* @state: dma_tx_state structure to return last/used cookies
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*
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* Report the status of the cookie, filling in the state structure if
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* non-NULL. No locking is required.
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*/
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static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
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dma_cookie_t cookie, struct dma_tx_state *state)
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{
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dma_cookie_t used, complete;
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used = chan->cookie;
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complete = chan->completed_cookie;
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barrier();
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if (state) {
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state->last = complete;
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state->used = used;
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state->residue = 0;
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}
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return dma_async_is_complete(cookie, complete, used);
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}
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static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
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{
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if (state)
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state->residue = residue;
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}
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#endif
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