static void ioat1_dma_start_null_desc(struct ioat_dma_chan *ioat)
{
	struct ioat_chan_common *chan = &ioat->base;
	struct ioat_desc_sw *desc;
	struct ioat_dma_descriptor *hw;

	spin_lock_bh(&ioat->desc_lock);

	desc = ioat1_dma_get_next_descriptor(ioat);

	if (!desc) {
		dev_err(to_dev(chan),
			"Unable to start null desc - get next desc failed\n");
		spin_unlock_bh(&ioat->desc_lock);
		return;
	}

	hw = desc->hw;
	hw->ctl = 0;
	hw->ctl_f.null = 1;
	hw->ctl_f.int_en = 1;
	hw->ctl_f.compl_write = 1;
	/* set size to non-zero value (channel returns error when size is 0) */
	hw->size = NULL_DESC_BUFFER_SIZE;
	hw->src_addr = 0;
	hw->dst_addr = 0;
	async_tx_ack(&desc->txd);
	hw->next = 0;
	list_add_tail(&desc->node, &ioat->used_desc);
	dump_desc_dbg(ioat, desc);

	ioat_set_chainaddr(ioat, desc->txd.phys);
	ioat_start(chan);
	spin_unlock_bh(&ioat->desc_lock);
}
static void ioat1_dma_start_null_desc(struct ioat_dma_chan *ioat)
{
	struct ioat_chan_common *chan = &ioat->base;
	struct ioat_desc_sw *desc;
	struct ioat_dma_descriptor *hw;

	spin_lock_bh(&ioat->desc_lock);

	desc = ioat1_dma_get_next_descriptor(ioat);

	if (!desc) {
		dev_err(to_dev(chan),
			"Unable to start null desc - get next desc failed\n");
		spin_unlock_bh(&ioat->desc_lock);
		return;
	}

	hw = desc->hw;
	hw->ctl = 0;
	hw->ctl_f.null = 1;
	hw->ctl_f.int_en = 1;
	hw->ctl_f.compl_write = 1;
	 
	hw->size = NULL_DESC_BUFFER_SIZE;
	hw->src_addr = 0;
	hw->dst_addr = 0;
	async_tx_ack(&desc->txd);
	hw->next = 0;
	list_add_tail(&desc->node, &ioat->used_desc);
	dump_desc_dbg(ioat, desc);

	ioat_set_chainaddr(ioat, desc->txd.phys);
	ioat_start(chan);
	spin_unlock_bh(&ioat->desc_lock);
}