[linux-sunxi] Re: [PATCH 07/10] dmaengine: sun6i: Retrieve channel count/max request from devicetree
On Montag, 4. September 2017 01:44:54 CEST André Przywara wrote:
> Hi,
>
> On 03/09/17 23:40, Stefan Brüns wrote:
> > To avoid introduction of a new compatible for each small SoC/DMA
> > controller
> > variation, move the definition of the channel count to the devicetree.
> >
> > The number of vchans is no longer explicit, but limited by the highest
> > port/DMA request number. The result is a slight overallocation for SoCs
> > with a sparse port mapping.
> >
> > Signed-off-by: Stefan Brüns
> > ---
> >
> > drivers/dma/sun6i-dma.c | 35 ++-
> > 1 file changed, 34 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> > index c69dadb853d2..bd4c2e4a759b 100644
> > --- a/drivers/dma/sun6i-dma.c
> > +++ b/drivers/dma/sun6i-dma.c
> > @@ -42,6 +42,9 @@
> >
> > #define DMA_STAT 0x30
> >
> > +/* Offset between DMA_IRQ_EN and DMA_IRQ_STAT limits number of channels
> > */
> > +#define DMA_MAX_CHANNELS (DMA_IRQ_CHAN_NR * 0x10 / 4)
> > +
> >
> > /*
> >
> > * sun8i specific registers
> > */
> >
> > @@ -65,7 +68,8 @@
> >
> > #define DMA_CHAN_LLI_ADDR 0x08
> >
> > #define DMA_CHAN_CUR_CFG 0x0c
> >
> > -#define DMA_CHAN_CFG_SRC_DRQ(x)((x) & 0x1f)
> > +#define DMA_CHAN_MAX_DRQ 0x1f
> > +#define DMA_CHAN_CFG_SRC_DRQ(x)((x) & DMA_CHAN_MAX_DRQ)
> >
> > #define DMA_CHAN_CFG_SRC_IO_MODE BIT(5)
> > #define DMA_CHAN_CFG_SRC_LINEAR_MODE (0 << 5)
> > #define DMA_CHAN_CFG_SRC_BURST_A31(x) (((x) & 0x3) << 7)
> >
> > @@ -1173,6 +1177,35 @@ static int sun6i_dma_probe(struct platform_device
> > *pdev)>
> > sdc->num_vchans = sdc->cfg->nr_max_vchans;
> > sdc->max_request = sdc->cfg->nr_max_requests;
> >
> > + ret = of_property_read_u32(np, "dma-channels", &sdc->num_pchans);
> > + if (ret && !sdc->num_pchans) {
> > + dev_err(&pdev->dev, "Can't get dma-channels.\n");
> > + return ret;
> > + }
> > +
> > + if (sdc->num_pchans > DMA_MAX_CHANNELS) {
> > + dev_err(&pdev->dev, "Number of dma-channels out of range.\n");
> > + return -EINVAL;
> > + }
> > +
> > + ret = of_property_read_u32(np, "dma-requests", &sdc->max_request);
> > + if (ret && !sdc->max_request) {
> > + dev_info(&pdev->dev, "Missing dma-requests, using %u.\n",
> > +DMA_CHAN_MAX_DRQ);
>
> Mmmh, is this mapping of "!sdc->max_request" -> DMA_CHAN_MAX_DRQ
> implemented somewhere else? Or is it just missing here:
> sdc->max_request = DMA_CHAN_MAX_DRQ;
Well spotted, that assignment is actually missing.
With this line added, your comment for patch 8/10 should also be addressed
(regarding the default value).
> Otherwise this is looking good, thanks for picking up the DT property
> approach!
>
> Cheers,
> Andre.
>
Kind regards,
Stefan
--
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home: +49 241 53809034 mobile: +49 151 50412019
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[linux-sunxi] Re: [PATCH 07/10] dmaengine: sun6i: Retrieve channel count/max request from devicetree
Hi,
On 03/09/17 23:40, Stefan Brüns wrote:
> To avoid introduction of a new compatible for each small SoC/DMA controller
> variation, move the definition of the channel count to the devicetree.
>
> The number of vchans is no longer explicit, but limited by the highest
> port/DMA request number. The result is a slight overallocation for SoCs
> with a sparse port mapping.
>
> Signed-off-by: Stefan Brüns
> ---
> drivers/dma/sun6i-dma.c | 35 ++-
> 1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index c69dadb853d2..bd4c2e4a759b 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -42,6 +42,9 @@
>
> #define DMA_STAT 0x30
>
> +/* Offset between DMA_IRQ_EN and DMA_IRQ_STAT limits number of channels */
> +#define DMA_MAX_CHANNELS (DMA_IRQ_CHAN_NR * 0x10 / 4)
> +
> /*
> * sun8i specific registers
> */
> @@ -65,7 +68,8 @@
> #define DMA_CHAN_LLI_ADDR0x08
>
> #define DMA_CHAN_CUR_CFG 0x0c
> -#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & 0x1f)
> +#define DMA_CHAN_MAX_DRQ 0x1f
> +#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & DMA_CHAN_MAX_DRQ)
> #define DMA_CHAN_CFG_SRC_IO_MODE BIT(5)
> #define DMA_CHAN_CFG_SRC_LINEAR_MODE (0 << 5)
> #define DMA_CHAN_CFG_SRC_BURST_A31(x)(((x) & 0x3) << 7)
> @@ -1173,6 +1177,35 @@ static int sun6i_dma_probe(struct platform_device
> *pdev)
> sdc->num_vchans = sdc->cfg->nr_max_vchans;
> sdc->max_request = sdc->cfg->nr_max_requests;
>
> + ret = of_property_read_u32(np, "dma-channels", &sdc->num_pchans);
> + if (ret && !sdc->num_pchans) {
> + dev_err(&pdev->dev, "Can't get dma-channels.\n");
> + return ret;
> + }
> +
> + if (sdc->num_pchans > DMA_MAX_CHANNELS) {
> + dev_err(&pdev->dev, "Number of dma-channels out of range.\n");
> + return -EINVAL;
> + }
> +
> + ret = of_property_read_u32(np, "dma-requests", &sdc->max_request);
> + if (ret && !sdc->max_request) {
> + dev_info(&pdev->dev, "Missing dma-requests, using %u.\n",
> + DMA_CHAN_MAX_DRQ);
Mmmh, is this mapping of "!sdc->max_request" -> DMA_CHAN_MAX_DRQ
implemented somewhere else? Or is it just missing here:
sdc->max_request = DMA_CHAN_MAX_DRQ;
Otherwise this is looking good, thanks for picking up the DT property
approach!
Cheers,
Andre.
> + }
> +
> + if (sdc->max_request > DMA_CHAN_MAX_DRQ) {
> + dev_err(&pdev->dev, "Value of dma-requests out of range.\n");
> + return -EINVAL;
> + }
> +
> + /*
> + * If the number of vchans is not specified, derive it from the
> + * highest port number, at most one channel per port and direction.
> + */
> + if (!sdc->num_vchans)
> + sdc->num_vchans = 2 * (sdc->max_request + 1);
> +
> sdc->pchans = devm_kcalloc(&pdev->dev, sdc->num_pchans,
> sizeof(struct sun6i_pchan), GFP_KERNEL);
> if (!sdc->pchans)
>
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