Re: [PATCH 2/2] dmaengine: Add support for the Analog Devices AXI-DMAC DMA controller

[Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

On Tue, Jul 28, 2015 at 11:38:06AM +0200, Lars-Peter Clausen wrote:
> +static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
> +{
> +	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
> +	struct virt_dma_desc *vdesc;
> +	struct axi_dmac_desc *desc;
> +	struct axi_dmac_sg *sg;
> +	unsigned int flags = 0;
> +	unsigned int val;
> +
> +	val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
> +	if (val) /* Queue is full, wait for the next SOT IRQ */
> +		return;
> +
> +	desc = chan->next_desc;
> +
> +	if (!desc) {
> +		vdesc = vchan_next_desc(&chan->vchan);
> +		if (!vdesc)
> +			return;
> +		list_move_tail(&vdesc->node, &chan->active_descs);
> +		desc = to_axi_dmac_desc(vdesc);
> +	}
> +	sg = &desc->sg[desc->num_submitted];
> +
> +	desc->num_submitted++;
> +	if (desc->num_submitted == desc->num_sgs)
> +		chan->next_desc = NULL;
> +	else
> +		chan->next_desc = desc;
> +
> +	sg->id = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_ID);
> +
> +	if (axi_dmac_dest_is_mem(chan)) {
> +		axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS, sg->dest_addr);
> +		axi_dmac_write(dmac, AXI_DMAC_REG_DEST_STRIDE, sg->dest_stride);
> +	}
> +
> +	if (axi_dmac_src_is_mem(chan)) {
> +		axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS, sg->src_addr);
> +		axi_dmac_write(dmac, AXI_DMAC_REG_SRC_STRIDE, sg->src_stride);
> +	}
> +
> +	/*
> +	 * If the hardware supports cyclic transfers and there is no callback to
> +	 * call, enable hw cyclic mode to avoid unnecessary interrupts.
> +	 */
> +	if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback)
> +		flags |= AXI_DMAC_FLAG_CYCLIC;
> +
> +	axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);
> +	axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, sg->y_len - 1);
> +	axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, flags);
> +	axi_dmac_write(dmac, AXI_DMAC_REG_START_TRANSFER, 1);
> +}

On Wed, Aug 19, 2015 at 06:55:34PM +0200, Lars-Peter Clausen wrote:
> On 08/19/2015 06:32 PM, Vinod Koul wrote:
> > On Tue, Jul 28, 2015 at 11:38:06AM +0200, Lars-Peter Clausen wrote:
> >> +	desc = axi_dmac_alloc_desc(sg_len);
> >> +	if (!desc)
> >> +		return NULL;
> >> +
> >> +	for_each_sg(sgl, sg, sg_len, i) {
> >> +		if (!axi_dmac_check_addr(chan, sg_dma_address(sg)) ||
> >> +		    !axi_dmac_check_len(chan, sg_dma_len(sg))) {
> >> +			kfree(desc);
> >> +			return NULL;
> >> +		}
> >> +
> >> +		if (direction == DMA_DEV_TO_MEM)
> >> +			desc->sg[i].dest_addr = sg_dma_address(sg);
> >> +		else
> >> +			desc->sg[i].src_addr = sg_dma_address(sg);
> > where is device side programming ?
> 
> in the start_transfer() function.

I must have missed that but still don't see it here, can you point me

-- 
~Vinod

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