Commit e81274cd authored by Dave Jiang's avatar Dave Jiang Committed by Vinod Koul
Browse files

dmaengine: add support to dynamic register/unregister of channels 



With the channel registration routines broken out, now add support code to
allow independent registering and unregistering of channels in a hotplug fashion.

Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/157965023364.73301.7821862091077299040.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent d2fb0a04

drivers/dma/dmaengine.c

+26 −8
Original line number Diff line number Diff line
@@ -986,6 +986,20 @@ static int __dma_async_device_channel_register(struct dma_device *device, 
	return rc;

}



int dma_async_device_channel_register(struct dma_device *device,

				      struct dma_chan *chan)

{

	int rc;



	rc = __dma_async_device_channel_register(device, chan, -1);

	if (rc < 0)

		return rc;



	dma_channel_rebalance();

	return 0;

}

EXPORT_SYMBOL_GPL(dma_async_device_channel_register);



static void __dma_async_device_channel_unregister(struct dma_device *device,

						  struct dma_chan *chan)

{
@@ -993,12 +1007,22 @@ static void __dma_async_device_channel_unregister(struct dma_device *device, 
		  "%s called while %d clients hold a reference\n",

		  __func__, chan->client_count);

	mutex_lock(&dma_list_mutex);

	list_del(&chan->device_node);

	device->chancnt--;

	chan->dev->chan = NULL;

	mutex_unlock(&dma_list_mutex);

	device_unregister(&chan->dev->device);

	free_percpu(chan->local);

}



void dma_async_device_channel_unregister(struct dma_device *device,

					 struct dma_chan *chan)

{

	__dma_async_device_channel_unregister(device, chan);

	dma_channel_rebalance();

}

EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister);



/**

 * dma_async_device_register - registers DMA devices found

 * @device: &dma_device
@@ -1121,12 +1145,6 @@ int dma_async_device_register(struct dma_device *device) 
			goto err_out;

	}



	if (!device->chancnt) {

		dev_err(device->dev, "%s: device has no channels!\n", __func__);

		rc = -ENODEV;

		goto err_out;

	}



	mutex_lock(&dma_list_mutex);

	/* take references on public channels */

	if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
@@ -1181,9 +1199,9 @@ EXPORT_SYMBOL(dma_async_device_register); 
 */

void dma_async_device_unregister(struct dma_device *device)

{

	struct dma_chan *chan;

	struct dma_chan *chan, *n;



	list_for_each_entry(chan, &device->channels, device_node)

	list_for_each_entry_safe(chan, n, &device->channels, device_node)

		__dma_async_device_channel_unregister(device, chan);



	mutex_lock(&dma_list_mutex);

include/linux/dmaengine.h

+4 −0
Original line number Diff line number Diff line
@@ -1521,6 +1521,10 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc) 
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);

void dma_async_device_channel_unregister(struct dma_device *device,

					 struct dma_chan *chan);

void dma_run_dependencies(struct dma_async_tx_descriptor *tx);

#define dma_request_channel(mask, x, y) \

	__dma_request_channel(&(mask), x, y, NULL)

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