dmaengine: sirf: set dma residue based on the current dma transfer position

sirfsoc_dma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,

	struct dma_tx_state *txstate)

{

	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);

	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);

	unsigned long flags;

	enum dma_status ret;

	struct sirfsoc_dma_desc *sdesc;

	int cid = schan->chan.chan_id;

	unsigned long dma_pos;

	unsigned long dma_request_bytes;

	unsigned long residue;

	spin_lock_irqsave(&schan->lock, flags);

	sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,

			node);

	dma_request_bytes = (sdesc->xlen + 1) * (sdesc->ylen + 1) *

		(sdesc->width * SIRFSOC_DMA_WORD_LEN);

	ret = dma_cookie_status(chan, cookie, txstate);

	dma_pos = readl_relaxed(sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR)

		<< 2;

	residue = dma_request_bytes - (dma_pos - sdesc->addr);

	dma_set_residue(txstate, residue);

	spin_unlock_irqrestore(&schan->lock, flags);

	return ret;