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Commit 1ff8df4f authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Vinod Koul
Browse files

dma: sh: provide a migration path for slave drivers to stop using .private 



This patch extends the sh dmaengine driver to support the preferred channel
selection and configuration method, instead of using the "private" field
from struct dma_chan. We add a standard filter function to be used by
slave drivers instead of implementing their own ones, and add support for
the DMA_SLAVE_CONFIG control operation, which must accompany the new
channel selection method. We still support the legacy .private channel
allocation method to cater for a smooth driver migration.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
[applied a trvial checkpath fix]
Signed-off-by: default avatarVinod Koul <vinod.koul@linux.intel.com>
parent c2cdb7e4

drivers/dma/sh/shdma-base.c

+89 −25
Original line number Diff line number Diff line
@@ -171,6 +171,65 @@ static struct shdma_desc *shdma_get_desc(struct shdma_chan *schan) 
	return NULL;

}



static int shdma_setup_slave(struct shdma_chan *schan, int slave_id)

{

	struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);

	const struct shdma_ops *ops = sdev->ops;

	int ret;



	if (slave_id < 0 || slave_id >= slave_num)

		return -EINVAL;



	if (test_and_set_bit(slave_id, shdma_slave_used))

		return -EBUSY;



	ret = ops->set_slave(schan, slave_id, false);

	if (ret < 0) {

		clear_bit(slave_id, shdma_slave_used);

		return ret;

	}



	schan->slave_id = slave_id;



	return 0;

}



/*

 * This is the standard shdma filter function to be used as a replacement to the

 * "old" method, using the .private pointer. If for some reason you allocate a

 * channel without slave data, use something like ERR_PTR(-EINVAL) as a filter

 * parameter. If this filter is used, the slave driver, after calling

 * dma_request_channel(), will also have to call dmaengine_slave_config() with

 * .slave_id, .direction, and either .src_addr or .dst_addr set.

 * NOTE: this filter doesn't support multiple DMAC drivers with the DMA_SLAVE

 * capability! If this becomes a requirement, hardware glue drivers, using this

 * services would have to provide their own filters, which first would check

 * the device driver, similar to how other DMAC drivers, e.g., sa11x0-dma.c, do

 * this, and only then, in case of a match, call this common filter.

 */

bool shdma_chan_filter(struct dma_chan *chan, void *arg)

{

	struct shdma_chan *schan = to_shdma_chan(chan);

	struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);

	const struct shdma_ops *ops = sdev->ops;

	int slave_id = (int)arg;

	int ret;



	if (slave_id < 0)

		/* No slave requested - arbitrary channel */

		return true;



	if (slave_id >= slave_num)

		return false;



	ret = ops->set_slave(schan, slave_id, true);

	if (ret < 0)

		return false;



	return true;

}

EXPORT_SYMBOL(shdma_chan_filter);



static int shdma_alloc_chan_resources(struct dma_chan *chan)

{

	struct shdma_chan *schan = to_shdma_chan(chan);
@@ -185,21 +244,10 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan) 
	 * never runs concurrently with itself or free_chan_resources.

	 */

	if (slave) {

		if (slave->slave_id < 0 || slave->slave_id >= slave_num) {

			ret = -EINVAL;

			goto evalid;

		}



		if (test_and_set_bit(slave->slave_id, shdma_slave_used)) {

			ret = -EBUSY;

			goto etestused;

		}



		ret = ops->set_slave(schan, slave->slave_id);

		/* Legacy mode: .private is set in filter */

		ret = shdma_setup_slave(schan, slave->slave_id);

		if (ret < 0)

			goto esetslave;



		schan->slave_id = slave->slave_id;

	} else {

		schan->slave_id = -EINVAL;

	}
@@ -228,8 +276,6 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan) 
	if (slave)

esetslave:

		clear_bit(slave->slave_id, shdma_slave_used);

etestused:

evalid:

	chan->private = NULL;

	return ret;

}
@@ -587,22 +633,40 @@ static int shdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, 
	struct shdma_chan *schan = to_shdma_chan(chan);

	struct shdma_dev *sdev = to_shdma_dev(chan->device);

	const struct shdma_ops *ops = sdev->ops;

	struct dma_slave_config *config;

	unsigned long flags;



	/* Only supports DMA_TERMINATE_ALL */

	if (cmd != DMA_TERMINATE_ALL)

		return -ENXIO;

	int ret;



	if (!chan)

		return -EINVAL;



	switch (cmd) {

	case DMA_TERMINATE_ALL:

		spin_lock_irqsave(&schan->chan_lock, flags);



		ops->halt_channel(schan);



		spin_unlock_irqrestore(&schan->chan_lock, flags);



		shdma_chan_ld_cleanup(schan, true);

		break;

	case DMA_SLAVE_CONFIG:

		/*

		 * So far only .slave_id is used, but the slave drivers are

		 * encouraged to also set a transfer direction and an address.

		 */

		if (!arg)

			return -EINVAL;

		/*

		 * We could lock this, but you shouldn't be configuring the

		 * channel, while using it...

		 */

		config = (struct dma_slave_config *)arg;

		ret = shdma_setup_slave(schan, config->slave_id);

		if (ret < 0)

			return ret;

		break;

	default:

		return -ENXIO;

	}



	return 0;

}

drivers/dma/sh/shdma.c

+3 −2
Original line number Diff line number Diff line
@@ -320,7 +320,7 @@ static const struct sh_dmae_slave_config *dmae_find_slave( 
}



static int sh_dmae_set_slave(struct shdma_chan *schan,

			     int slave_id)

			     int slave_id, bool try)

{

	struct sh_dmae_chan *sh_chan = container_of(schan, struct sh_dmae_chan,

						    shdma_chan);
@@ -328,6 +328,7 @@ static int sh_dmae_set_slave(struct shdma_chan *schan, 
	if (!cfg)

		return -ENODEV;



	if (!try)

		sh_chan->config = cfg;



	return 0;

include/linux/sh_dma.h

+2 −0
Original line number Diff line number Diff line
@@ -99,4 +99,6 @@ struct sh_dmae_pdata { 
#define CHCR_TE	0x00000002

#define CHCR_IE	0x00000004



bool shdma_chan_filter(struct dma_chan *chan, void *arg);



#endif

include/linux/shdma-base.h

+1 −1
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ struct shdma_ops { 
	dma_addr_t (*slave_addr)(struct shdma_chan *);

	int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,

			  dma_addr_t, dma_addr_t, size_t *);

	int (*set_slave)(struct shdma_chan *, int);

	int (*set_slave)(struct shdma_chan *, int, bool);

	void (*setup_xfer)(struct shdma_chan *, int);

	void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);

	struct shdma_desc *(*embedded_desc)(void *, int);