Re: [PATCH v3] dmaengine: Add support for MEMCPY for imx-dma.

From: Vinod Koul
Date: Mon Feb 06 2012 - 06:36:23 EST


On Tue, 2012-01-31 at 11:47 +0100, Javier Martin wrote:
> MEMCPY transfers allow DMA copies from memory to
> memory. This patch has been tested with dmatest
> device driver.
>
> Signed-off-by: Javier Martin <javier.martin@xxxxxxxxxxxxxxxxx>
> ---
> drivers/dma/imx-dma.c | 36 +++++++++++++++++++++++++++++++++++-
> 1 files changed, 35 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> index 3296a73..9aa6e85 100644
> --- a/drivers/dma/imx-dma.c
> +++ b/drivers/dma/imx-dma.c
> @@ -196,7 +196,8 @@ static int imxdma_alloc_chan_resources(struct dma_chan *chan)
> struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
> struct imx_dma_data *data = chan->private;
>
> - imxdmac->dma_request = data->dma_request;
> + if (data != NULL)
> + imxdmac->dma_request = data->dma_request;
if you support memcopy then why should it _always_ require private
pointer?
>
> dma_async_tx_descriptor_init(&imxdmac->desc, chan);
> imxdmac->desc.tx_submit = imxdma_tx_submit;
> @@ -328,6 +329,36 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
> return &imxdmac->desc;
> }
>
> +static struct dma_async_tx_descriptor *imxdma_prep_dma_memcpy(
> + struct dma_chan *chan, dma_addr_t dest,
> + dma_addr_t src, size_t len, unsigned long flags)
> +{
> + struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
> + struct imxdma_engine *imxdma = imxdmac->imxdma;
> + int ret;
> +
> + dev_dbg(imxdma->dev, "%s channel: %d src=0x%x dst=0x%x len=%d\n",
> + __func__, imxdmac->channel, src, dest, len);
> +
> + if (imxdmac->status == DMA_IN_PROGRESS)
> + return NULL;
thats not right, you should be able to prepare descriptors even if dmac
is busy. Prepare != start
> + imxdmac->status = DMA_IN_PROGRESS;
> +
> + ret = imx_dma_config_channel(imxdmac->imxdma_channel,
> + IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
> + IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
> + 0, 0);
> + if (ret)
> + return NULL;
> +
> + ret = imx_dma_setup_single(imxdmac->imxdma_channel, src, len,
> + dest, DMA_MODE_WRITE);
> + if (ret)
> + return NULL;
> +
> + return &imxdmac->desc;
> +}
> +
> static void imxdma_issue_pending(struct dma_chan *chan)
> {
> struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
> @@ -349,6 +380,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
>
> dma_cap_set(DMA_SLAVE, imxdma->dma_device.cap_mask);
> dma_cap_set(DMA_CYCLIC, imxdma->dma_device.cap_mask);
> + dma_cap_set(DMA_MEMCPY, imxdma->dma_device.cap_mask);
>
> /* Initialize channel parameters */
> for (i = 0; i < MAX_DMA_CHANNELS; i++) {
> @@ -382,11 +414,13 @@ static int __init imxdma_probe(struct platform_device *pdev)
> imxdma->dma_device.device_tx_status = imxdma_tx_status;
> imxdma->dma_device.device_prep_slave_sg = imxdma_prep_slave_sg;
> imxdma->dma_device.device_prep_dma_cyclic = imxdma_prep_dma_cyclic;
> + imxdma->dma_device.device_prep_dma_memcpy = imxdma_prep_dma_memcpy;
> imxdma->dma_device.device_control = imxdma_control;
> imxdma->dma_device.device_issue_pending = imxdma_issue_pending;
>
> platform_set_drvdata(pdev, imxdma);
>
> + imxdma->dma_device.copy_align = 2; /* 2^2 = 4 bytes alignment */
what is this magic number?
> imxdma->dma_device.dev->dma_parms = &imxdma->dma_parms;
> dma_set_max_seg_size(imxdma->dma_device.dev, 0xffffff);
>


--
~Vinod

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