linux-imx

/* SPDX-License-Identifier: GPL-2.0 */

/*

 * 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