> -----Original Message-----
> From: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> Sent: 19 November 2020 8:10 AM
> To: Sia, Jee Heng <jee.heng.sia@xxxxxxxxx>; vkoul@xxxxxxxxxx; robh+dt@xxxxxxxxxx
> Cc: andriy.shevchenko@xxxxxxxxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 08/15] dmaengine: dw-axi-dmac: Support
> of_dma_controller_register()
>
> Hi Sia,
>
> > Subject: [PATCH v4 08/15] dmaengine: dw-axi-dmac: Support
> > of_dma_controller_register()
> >
> > Add support for of_dma_controller_register() so that DMA clients can
> > pass in device handshake number to the AxiDMA driver.
> >
> > DMA clients shall code the device handshake number in the Device tree.
> > When DMA activities are needed, DMA clients shall invoke OF helper
> > function to pass in the device handshake number to the AxiDMA.
> >
> > Without register to the of_dma_controller_register(), data transfer
> > between memory to device and device to memory operations would failed.
> >
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sia Jee Heng <jee.heng.sia@xxxxxxxxx>
> > ---
> > .../dma/dw-axi-dmac/dw-axi-dmac-platform.c | 26 +++++++++++++++++++
> > drivers/dma/dw-axi-dmac/dw-axi-dmac.h | 1 +
> > 2 files changed, 27 insertions(+)
> >
> > diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > index b5f92f9cb2bc..72871b8738be 100644
> > --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > @@ -20,6 +20,7 @@
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > +#include <linux/of_dma.h>
> > #include <linux/platform_device.h>
> > #include <linux/pm_runtime.h>
> > #include <linux/property.h>
> > @@ -1044,6 +1045,22 @@ static int __maybe_unused
> axi_dma_runtime_resume(struct device *dev)
> > return axi_dma_resume(chip);
> > }
> >
> > +static struct dma_chan *dw_axi_dma_of_xlate(struct of_phandle_args
> *dma_spec,
> > + struct of_dma *ofdma) {
> > + struct dw_axi_dma *dw = ofdma->of_dma_data;
> > + struct axi_dma_chan *chan;
> > + struct dma_chan *dchan;
> > +
> > + dchan = dma_get_any_slave_channel(&dw->dma);
> > + if (!dchan)
> > + return NULL;
> > +
> > + chan = dchan_to_axi_dma_chan(dchan);
> > + chan->hw_hs_num = dma_spec->args[0];
> > + return dchan;
> > +}
> > +
> > static int parse_device_properties(struct axi_dma_chip *chip) {
> > struct device *dev = chip->dev; @@ -1233,6 +1250,13 @@ static
> > int dw_probe(struct platform_device *pdev)
> > if (ret)
> > goto err_pm_disable;
> >
> > + /* Register with OF helpers for DMA lookups */
> > + ret = of_dma_controller_register(pdev->dev.of_node,
> > + dw_axi_dma_of_xlate, dw);
> > + if (ret < 0)
> > + dev_warn(&pdev->dev,
> > + "Failed to register OF DMA controller,
> > + fallback to MEM_TO_MEM mode\n");
> > +
> > dev_info(chip->dev, "DesignWare AXI DMA Controller, %d channels\n",
> > dw->hdata->nr_channels);
> >
> > @@ -1266,6 +1290,8 @@ static int dw_remove(struct platform_device
> > *pdev)
> >
> > devm_free_irq(chip->dev, chip->irq, chip);
> >
> > + of_dma_controller_free(chip->dev->of_node);
> > +
> > list_for_each_entry_safe(chan, _chan, &dw->dma.channels,
> > vc.chan.device_node) {
> > list_del(&chan->vc.chan.device_node);
> > diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > index a26b0a242a93..651874e5c88f 100644
> > --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > @@ -37,6 +37,7 @@ struct axi_dma_chan {
> > struct axi_dma_chip *chip;
> > void __iomem *chan_regs;
> > u8 id;
> > + u8 hw_hs_num;
> Just a nitpick: 'hw_hs_num' sounds quite obfuscated. Could it be
> 'hw_handshake_num' for example?
[>>] OK, will rename it to hw_handshake_num .
>
> > atomic_t descs_allocated;
> >
> > struct dma_pool *desc_pool;
> > --
> > 2.18.0
> >
