Re: [PATCH] dmaengine: add channel device name to channel registration

[Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>]

Hi Vinod,

On 12/21/23 17:13, Vinod Koul wrote:
> On 13-12-23, 18:40, Amelie Delaunay wrote:
> > Channel device name is used for sysfs, but also by dmatest filter function.
> >
> > With dynamic channel registration, channels can be registered after dma
> > controller registration. Users may want to have specific channel names.
> >
> > If name is NULL, the channel name relies on previous implementation,
> > dma<controller_device_id>chan<channel_device_id>.
>
> lgtm, where is the user for this..?

I'll send beginning of next year a DMA controller driver for STM32MP25 
SoC family. It relies on the dynamic channel registration. It will be a 
user of this dma_async_device_channel_register(struct dma_device 
*device, struct dma_chan *chan, const char *name).

Regards,
Amelie

> > Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
> > ---
> >   drivers/dma/dmaengine.c   | 16 ++++++++++------
> >   drivers/dma/idxd/dma.c    |  2 +-
> >   include/linux/dmaengine.h |  3 ++-
> >   3 files changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> > index b7388ae62d7f..7848428da2d6 100644
> > --- a/drivers/dma/dmaengine.c
> > +++ b/drivers/dma/dmaengine.c
> > @@ -1037,7 +1037,8 @@ static int get_dma_id(struct dma_device *device)
> >   }
> >   
> >   static int __dma_async_device_channel_register(struct dma_device *device,
> > -					       struct dma_chan *chan)
> > +					       struct dma_chan *chan,
> > +					       const char *name)
> >   {
> >   	int rc;
> >   
> > @@ -1066,8 +1067,10 @@ static int __dma_async_device_channel_register(struct dma_device *device,
> >   	chan->dev->device.parent = device->dev;
> >   	chan->dev->chan = chan;
> >   	chan->dev->dev_id = device->dev_id;
> > -	dev_set_name(&chan->dev->device, "dma%dchan%d",
> > -		     device->dev_id, chan->chan_id);
> > +	if (!name)
> > +		dev_set_name(&chan->dev->device, "dma%dchan%d", device->dev_id, chan->chan_id);
> > +	else
> > +		dev_set_name(&chan->dev->device, name);
> >   	rc = device_register(&chan->dev->device);
> >   	if (rc)
> >   		goto err_out_ida;
> > @@ -1087,11 +1090,12 @@ static int __dma_async_device_channel_register(struct dma_device *device,
> >   }
> >   
> >   int dma_async_device_channel_register(struct dma_device *device,
> > -				      struct dma_chan *chan)
> > +				      struct dma_chan *chan,
> > +				      const char *name)
> >   {
> >   	int rc;
> >   
> > -	rc = __dma_async_device_channel_register(device, chan);
> > +	rc = __dma_async_device_channel_register(device, chan, name);
> >   	if (rc < 0)
> >   		return rc;
> >   
> > @@ -1200,7 +1204,7 @@ int dma_async_device_register(struct dma_device *device)
> >   
> >   	/* represent channels in sysfs. Probably want devs too */
> >   	list_for_each_entry(chan, &device->channels, device_node) {
> > -		rc = __dma_async_device_channel_register(device, chan);
> > +		rc = __dma_async_device_channel_register(device, chan, NULL);
> >   		if (rc < 0)
> >   			goto err_out;
> >   	}
> > diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
> > index 47a01893cfdb..101a265567a9 100644
> > --- a/drivers/dma/idxd/dma.c
> > +++ b/drivers/dma/idxd/dma.c
> > @@ -269,7 +269,7 @@ static int idxd_register_dma_channel(struct idxd_wq *wq)
> >   		desc->txd.tx_submit = idxd_dma_tx_submit;
> >   	}
> >   
> > -	rc = dma_async_device_channel_register(dma, chan);
> > +	rc = dma_async_device_channel_register(dma, chan, NULL);
> >   	if (rc < 0) {
> >   		kfree(idxd_chan);
> >   		return rc;
> > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> > index 3df70d6131c8..cbad92cc3e0b 100644
> > --- a/include/linux/dmaengine.h
> > +++ b/include/linux/dmaengine.h
> > @@ -1574,7 +1574,8 @@ int dma_async_device_register(struct dma_device *device);
> >   int dmaenginem_async_device_register(struct dma_device *device);
> >   void dma_async_device_unregister(struct dma_device *device);
> >   int dma_async_device_channel_register(struct dma_device *device,
> > -				      struct dma_chan *chan);
> > +				      struct dma_chan *chan,
> > +				      const char *name);
> >   void dma_async_device_channel_unregister(struct dma_device *device,
> >   					 struct dma_chan *chan);
> >   void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
> > --
> > 2.25.1