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Commit 8010dad5 authored by Stephen Warren's avatar Stephen Warren Committed by Vinod Koul
Browse files

dma: add dma_get_any_slave_channel(), for use in of_xlate() 



mmp_pdma.c implements a custom of_xlate() function that is 95% identical
to what Tegra will need. Create a function to implement the common part,
so everyone doesn't just cut/paste the implementation.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 6ce4eac1

drivers/dma/dmaengine.c

+28 −0
Original line number Diff line number Diff line
@@ -535,6 +535,34 @@ struct dma_chan *dma_get_slave_channel(struct dma_chan *chan) 
}

EXPORT_SYMBOL_GPL(dma_get_slave_channel);



struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)

{

	dma_cap_mask_t mask;

	struct dma_chan *chan;

	int err;



	dma_cap_zero(mask);

	dma_cap_set(DMA_SLAVE, mask);



	/* lock against __dma_request_channel */

	mutex_lock(&dma_list_mutex);



	chan = private_candidate(&mask, device, NULL, NULL);

	if (chan) {

		err = dma_chan_get(chan);

		if (err) {

			pr_debug("%s: failed to get %s: (%d)\n",

				__func__, dma_chan_name(chan), err);

			chan = NULL;

		}

	}



	mutex_unlock(&dma_list_mutex);



	return chan;

}

EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);



/**

 * __dma_request_channel - try to allocate an exclusive channel

 * @mask: capabilities that the channel must satisfy

drivers/dma/mmp_pdma.c

+7 −23
Original line number Diff line number Diff line
@@ -893,33 +893,17 @@ static struct dma_chan *mmp_pdma_dma_xlate(struct of_phandle_args *dma_spec, 
					   struct of_dma *ofdma)

{

	struct mmp_pdma_device *d = ofdma->of_dma_data;

	struct dma_chan *chan, *candidate;

	struct dma_chan *chan;

	struct mmp_pdma_chan *c;



retry:

	candidate = NULL;



	/* walk the list of channels registered with the current instance and

	 * find one that is currently unused */

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

		if (chan->client_count == 0) {

			candidate = chan;

			break;

		}



	if (!candidate)

	chan = dma_get_any_slave_channel(&d->device);

	if (!chan)

		return NULL;



	/* dma_get_slave_channel will return NULL if we lost a race between

	 * the lookup and the reservation */

	chan = dma_get_slave_channel(candidate);



	if (chan) {

		struct mmp_pdma_chan *c = to_mmp_pdma_chan(chan);

	c = to_mmp_pdma_chan(chan);

	c->drcmr = dma_spec->args[0];

		return chan;

	}



	goto retry;

	return chan;

}



static int mmp_pdma_probe(struct platform_device *op)

include/linux/dmaengine.h

+1 −0
Original line number Diff line number Diff line
@@ -1079,6 +1079,7 @@ int dma_async_device_register(struct dma_device *device); 
void dma_async_device_unregister(struct dma_device *device);

void dma_run_dependencies(struct dma_async_tx_descriptor *tx);

struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);

struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);

struct dma_chan *net_dma_find_channel(void);

#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)

#define dma_request_slave_channel_compat(mask, x, y, dev, name) \