dmaengine: add channel device name to channel registration

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>.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20240531150712.2503554-11-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: ADESTM

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;
 
@@ -1203,7 +1207,7 @@ 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;
 	}

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;

include/linux/dmaengine.h

@@ -1575,7 +1575,8 @@ 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);