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Date: Tue, 25 Nov 2014 14:56:23 +0100
From: Krzysztof Kozłowski <k.kozlowski@...sung.com>
To: Robert Baldyga <r.baldyga@...sung.com>, vinod.koul@...el.com
Cc: dan.j.williams@...el.com, ars@...afoo.de,
dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
m.szyprowski@...sung.com, l.czerwinski@...sung.com
Subject: Re: [PATCH 1/2] dma: pl330: improve pl330_tx_status() function
On 25.11.2014 13:25, Robert Baldyga wrote:
> This patch adds possibility to read residue of DMA transfer. It's useful
> when we want to know how many bytes have been transfered before we
> terminate channel. It can take place, for example, on timeout interrupt.
>
> Signed-off-by: Lukasz Czerwinski <l.czerwinski@...sung.com>
> Signed-off-by: Robert Baldyga <r.baldyga@...sung.com>
> ---
> drivers/dma/pl330.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 60 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index d5149aa..c32806d 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -437,6 +437,7 @@ struct dma_pl330_chan {
> /* For D-to-M and M-to-D channels */
> int burst_sz; /* the peripheral fifo width */
> int burst_len; /* the number of burst */
> + int transfered;
> dma_addr_t fifo_addr;
>
> /* for cyclic capability */
> @@ -500,6 +501,9 @@ struct dma_pl330_desc {
>
> enum desc_status status;
>
> + int bytes_requested;
> + int direction;
> +
> /* The channel which currently holds this desc */
> struct dma_pl330_chan *pchan;
>
> @@ -2156,11 +2160,60 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
> spin_unlock_irqrestore(&pch->lock, flags);
> }
>
> +int pl330_get_current_xferred_count(struct dma_pl330_chan *pch,
> + struct dma_pl330_desc *desc)
> +{
> + u32 val, addr;
> + struct pl330_thread *thrd = pch->thread;
> + void __iomem *regs = thrd->dmac->base;
> +
> + val = addr = 0;
> + switch (desc->direction) {
> + case DMA_MEM_TO_DEV:
> + val = readl(regs + SA(thrd->id));
> + addr = desc->px.src_addr;
> + break;
> + case DMA_DEV_TO_MEM:
> + val = readl(regs + DA(thrd->id));
> + addr = desc->px.dst_addr;
> + break;
> + default:
> + break;
> + }
> + return val - addr;
> +}
> +
> static enum dma_status
> pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
> struct dma_tx_state *txstate)
> {
> - return dma_cookie_status(chan, cookie, txstate);
> + enum dma_status ret;
> + unsigned long flags;
> + struct dma_pl330_desc *desc;
> + struct dma_pl330_chan *pch = to_pchan(chan);
> + unsigned int bytes_transferred;
> + unsigned int residual;
> +
> + /* Check in pending list */
> + spin_lock_irqsave(&pch->lock, flags);
> + list_for_each_entry(desc, &pch->work_list, node) {
> + if (desc->txd.cookie == cookie) {
> + bytes_transferred =
> + pl330_get_current_xferred_count(pch, desc);
As in 2nd patch - what if this get called after all transfers complete?
You're touching the device here so pm_runtime_get_sync()/put/autosuspend
may be needed.
Best regards,
Krzysztof
> + residual = desc->bytes_requested -
> + bytes_transferred % desc->bytes_requested;
> + dma_set_residue(txstate, residual);
> + ret = desc->status;
> + spin_unlock_irqrestore(&pch->lock, flags);
> + return ret;
> + }
> + }
> + spin_unlock_irqrestore(&pch->lock, flags);
> +
> + ret = dma_cookie_status(chan, cookie, txstate);
> + dma_set_residue(txstate, pch->transfered);
> +
> + return ret;
> }
>
> static void pl330_issue_pending(struct dma_chan *chan)
> @@ -2421,10 +2474,13 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
> break;
> }
>
> + desc->direction = direction;
> desc->rqtype = direction;
> desc->rqcfg.brst_size = pch->burst_sz;
> desc->rqcfg.brst_len = 1;
> + desc->bytes_requested = period_len;
> fill_px(&desc->px, dst, src, period_len);
> + pch->transfered = 0;
>
> if (!first)
> first = desc;
> @@ -2554,9 +2610,12 @@ pl330_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> sg_dma_address(sg), addr, sg_dma_len(sg));
> }
>
> + desc->direction = direction;
> desc->rqcfg.brst_size = pch->burst_sz;
> desc->rqcfg.brst_len = 1;
> desc->rqtype = direction;
> + desc->bytes_requested = sg_dma_len(sg);
> + pch->transfered = 0;
> }
>
> /* Return the last desc in the chain */
>
--
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