RE: [PATCH v1 1/3] dmaengine: sf-pdma: Support of_dma_controller_register()

Shravan.Chippa
2023-09-22T10:59:22Z

> -----Original Message-----
> From: Emil Renner Berthing <emil.renner.berthing@canonical.com>
> Sent: Friday, September 22, 2023 4:16 PM
> To: shravan Chippa - I35088 <Shravan.Chippa@microchip.com>;
> green.wan@sifive.com; vkoul@kernel.org; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; palmer@dabbelt.com;
> paul.walmsley@sifive.com; conor+dt@kernel.org; palmer@sifive.com
> Cc: dmaengine@vger.kernel.org; devicetree@vger.kernel.org; linux-
> riscv@lists.infradead.org; linux-kernel@vger.kernel.org; Nagasuresh Relli -
> I67208 <Nagasuresh.Relli@microchip.com>; Praveen Kumar - I30718
> <Praveen.Kumar@microchip.com>
> Subject: Re: [PATCH v1 1/3] dmaengine: sf-pdma: Support
> of_dma_controller_register()
>
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> shravan chippa wrote:
> > From: Shravan Chippa <shravan.chippa@microchip.com>
> >
> > Update sf-pdma driver to adopt generic DMA device tree bindings.
> > It calls of_dma_controller_register() with sf-pdma specific
> > of_dma_xlate to get the generic DMA device tree helper support and the
> > DMA clients can look up the sf-pdma controller using standard APIs.
> >
> > Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com>
> > ---
> > drivers/dma/sf-pdma/sf-pdma.c | 41
> > +++++++++++++++++++++++++++++++++++
> > 1 file changed, 41 insertions(+)
> >
> > diff --git a/drivers/dma/sf-pdma/sf-pdma.c
> > b/drivers/dma/sf-pdma/sf-pdma.c index d1c6956af452..c7558c9f9ac3
> > 100644
> > --- a/drivers/dma/sf-pdma/sf-pdma.c
> > +++ b/drivers/dma/sf-pdma/sf-pdma.c
> > @@ -20,6 +20,7 @@
> > #include <linux/mod_devicetable.h>
> > #include <linux/dma-mapping.h>
> > #include <linux/of.h>
> > +#include <linux/of_dma.h>
> > #include <linux/slab.h>
> >
> > #include "sf-pdma.h"
> > @@ -490,6 +491,33 @@ static void sf_pdma_setup_chans(struct sf_pdma
> *pdma)
> > }
> > }
> >
> > +static struct dma_chan *sf_pdma_of_xlate(struct of_phandle_args
> *dma_spec,
> > + struct of_dma *ofdma) {
> > + struct sf_pdma *pdma = ofdma->of_dma_data;
> > + struct device *dev = pdma->dma_dev.dev;
> > + struct sf_pdma_chan *chan;
> > + struct dma_chan *c;
> > + u32 channel_id;
> > +
> > + if (dma_spec->args_count != 1) {
> > + dev_err(dev, "Bad number of cells\n");
> > + return NULL;
> > + }
> > +
> > + channel_id = dma_spec->args[0];
> > +
> > + chan = &pdma->chans[channel_id];
> > +
> > + c = dma_get_slave_channel(&chan->vchan.chan);
> > + if (!c) {
> > + dev_err(dev, "No more channels available\n");
> > + return NULL;
> > + }
> > +
> > + return c;
> > +}
> > +
> > static int sf_pdma_probe(struct platform_device *pdev) {
> > struct sf_pdma *pdma;
> > @@ -563,7 +591,20 @@ static int sf_pdma_probe(struct platform_device
> *pdev)
> > return ret;
> > }
> >
> > + ret = of_dma_controller_register(pdev->dev.of_node,
> > + sf_pdma_of_xlate, pdma);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev,
> > + "Can't register SiFive Platform OF_DMA. (%d)\n", ret);
> > + goto err_unregister;
> > + }
> > +
>
> Hi Shrivan,
>
> Doesn't this need a matching unregister/free call in the sf_pdma_remove
> function?
>
> /Emil
>

Will add of_dma_controller_free(np) call in the sf_pdma_remove().

> > return 0;
> > +
> > +err_unregister:
> > + dma_async_device_unregister(&pdma->dma_dev);
> > +
> > + return ret;
> > }
> >
> > static int sf_pdma_remove(struct platform_device *pdev)
> > --
> > 2.34.1
> >
> >
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