dmaengine.h
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/*
* The contents of this file are private to DMA engine drivers, and is not
* part of the API to be used by DMA engine users.
*/
#ifndef DMAENGINE_H
#define DMAENGINE_H
#include <linux/bug.h>
#include <linux/dmaengine.h>
/**
* dma_cookie_init - initialize the cookies for a DMA channel
* @chan: dma channel to initialize
*/
static inline void dma_cookie_init(struct dma_chan *chan)
{
chan->cookie = DMA_MIN_COOKIE;
chan->completed_cookie = DMA_MIN_COOKIE;
}
/**
* dma_cookie_assign - assign a DMA engine cookie to the descriptor
* @tx: descriptor needing cookie
*
* Assign a unique non-zero per-channel cookie to the descriptor.
* Note: caller is expected to hold a lock to prevent concurrency.
*/
static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
{
struct dma_chan *chan = tx->chan;
dma_cookie_t cookie;
cookie = chan->cookie + 1;
if (cookie < DMA_MIN_COOKIE)
cookie = DMA_MIN_COOKIE;
tx->cookie = chan->cookie = cookie;
return cookie;
}
/**
* dma_cookie_complete - complete a descriptor
* @tx: descriptor to complete
*
* Mark this descriptor complete by updating the channels completed
* cookie marker. Zero the descriptors cookie to prevent accidental
* repeated completions.
*
* Note: caller is expected to hold a lock to prevent concurrency.
*/
static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
{
BUG_ON(tx->cookie < DMA_MIN_COOKIE);
tx->chan->completed_cookie = tx->cookie;
tx->cookie = 0;
}
/**
* dma_cookie_status - report cookie status
* @chan: dma channel
* @cookie: cookie we are interested in
* @state: dma_tx_state structure to return last/used cookies
*
* Report the status of the cookie, filling in the state structure if
* non-NULL. No locking is required.
*/
static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
dma_cookie_t cookie, struct dma_tx_state *state)
{
dma_cookie_t used, complete;
used = chan->cookie;
complete = chan->completed_cookie;
barrier();
if (state) {
state->last = complete;
state->used = used;
state->residue = 0;
}
return dma_async_is_complete(cookie, complete, used);
}
static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
{
if (state)
state->residue = residue;
}
#endif