linux-kernel - Re: [PATCH v3 2/3] dmaengine: ptdma: Register pass-through engine as a DMA resource

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Message-ID: <20200124060532.GD2841@vkoul-mobl>
Date:   Fri, 24 Jan 2020 11:35:32 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Sanjay R Mehta <Sanju.Mehta@....com>
Cc:     gregkh@...uxfoundation.org, dan.j.williams@...el.com,
        Thomas.Lendacky@....com, Shyam-sundar.S-k@....com,
        Nehal-bakulchandra.Shah@....com, robh@...nel.org,
        mchehab+samsung@...nel.org, davem@...emloft.net,
        Jonathan.Cameron@...wei.com, linux-kernel@...r.kernel.org,
        dmaengine@...r.kernel.org
Subject: Re: [PATCH v3 2/3] dmaengine: ptdma: Register pass-through engine as
 a DMA resource

On 21-01-20, 03:04, Sanjay R Mehta wrote:

> +static void pt_free_chan_resources(struct dma_chan *dma_chan)
> +{
> +	struct pt_dma_chan *chan = container_of(dma_chan, struct pt_dma_chan,
> +						 dma_chan);
> +	unsigned long flags;
> +
> +	dev_dbg(chan->pt->dev, "%s - chan=%p\n", __func__, chan);
> +
> +	spin_lock_irqsave(&chan->lock, flags);
> +
> +	pt_free_desc_resources(chan->pt, &chan->complete);
> +	pt_free_desc_resources(chan->pt, &chan->active);
> +	pt_free_desc_resources(chan->pt, &chan->pending);
> +	pt_free_desc_resources(chan->pt, &chan->created);

can you use the virt-dma layer instead for list and descriptor
management..

> +static enum dma_status pt_tx_status(struct dma_chan *dma_chan,
> +				    dma_cookie_t cookie,
> +				    struct dma_tx_state *state)
> +{
> +	struct pt_dma_chan *chan = container_of(dma_chan, struct pt_dma_chan,
> +						 dma_chan);
> +	struct pt_dma_desc *desc;
> +	enum dma_status ret;
> +	unsigned long flags;
> +
> +	if (chan->status == DMA_PAUSED) {
> +		ret = DMA_PAUSED;

the pt_tx_status is for a specific cookie and not for the channel, so
you need to return status of the cookie which may have been completed or
pending (where pause makes sense)

> +static int pt_pause(struct dma_chan *dma_chan)
> +{
> +	struct pt_dma_chan *chan = container_of(dma_chan, struct pt_dma_chan,
> +						 dma_chan);
> +
> +	chan->status = DMA_PAUSED;
> +
> +	/*TODO: Wait for active DMA to complete before returning? */

When will the be resolved :)

-- 
~Vinod