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Commit 411fdaf8 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Vinod Koul
Browse files

dmaengine: shdma: use normal interface for passing slave id 



in dma_slave_config, which is incompatible with the way that the
dmaengine API normally works.

I've had a closer look at the existing code now and found that all
slave drivers that pass a slave_id in dma_slave_config for SH do that
right after passing the same ID into shdma_chan_filter, so we can just
rely on that. However, the various shdma drivers currently do not
remember the slave ID that was passed into the filter function when
used in non-DT mode and only check the value to find a matching channel,
unlike all other drivers.

There might still be drivers that are not part of the kernel that rely
on setting the slave_id to some other value, so to be on the safe side,
this adds another 'real_slave_id' field to shdma_chan that remembers
the ID and uses it when a driver passes a zero slave_id in dma_slave_config,
like most drivers do.

Eventually, the real_slave_id and slave_id fields should just get merged
into one field, but that requires other changes.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent c517d838

drivers/dma/sh/shdma-base.c

+53 −20
Original line number Diff line number Diff line
@@ -171,8 +171,7 @@ 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,

			     dma_addr_t slave_addr)

static int shdma_setup_slave(struct shdma_chan *schan, dma_addr_t slave_addr)

{

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

	const struct shdma_ops *ops = sdev->ops;
@@ -183,25 +182,23 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id, 
		ret = ops->set_slave(schan, match, slave_addr, true);

		if (ret < 0)

			return ret;



		slave_id = schan->slave_id;

	} else {

		match = slave_id;

		match = schan->real_slave_id;

	}



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

	if (schan->real_slave_id < 0 || schan->real_slave_id >= slave_num)

		return -EINVAL;



	if (test_and_set_bit(slave_id, shdma_slave_used))

	if (test_and_set_bit(schan->real_slave_id, shdma_slave_used))

		return -EBUSY;



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

	if (ret < 0) {

		clear_bit(slave_id, shdma_slave_used);

		clear_bit(schan->real_slave_id, shdma_slave_used);

		return ret;

	}



	schan->slave_id = slave_id;

	schan->slave_id = schan->real_slave_id;



	return 0;

}
@@ -221,10 +218,12 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan) 
	 */

	if (slave) {

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

		ret = shdma_setup_slave(schan, slave->slave_id, 0);

		schan->real_slave_id = slave->slave_id;

		ret = shdma_setup_slave(schan, 0);

		if (ret < 0)

			goto esetslave;

	} else {

		/* Normal mode: real_slave_id was set by filter */

		schan->slave_id = -EINVAL;

	}
@@ -258,11 +257,14 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan) 


/*

 * 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

 * "old" method, using the .private pointer.

 * You always have to pass a valid slave id as the argument, old drivers that

 * pass ERR_PTR(-EINVAL) as a filter parameter and set it up in dma_slave_config

 * need to be updated so we can remove the slave_id field from dma_slave_config.

 * 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.

 * .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
@@ -276,7 +278,7 @@ bool shdma_chan_filter(struct dma_chan *chan, void *arg) 
{

	struct shdma_chan *schan;

	struct shdma_dev *sdev;

	int match = (long)arg;

	int slave_id = (long)arg;

	int ret;



	/* Only support channels handled by this driver. */
@@ -284,19 +286,39 @@ bool shdma_chan_filter(struct dma_chan *chan, void *arg) 
	    shdma_alloc_chan_resources)

		return false;



	if (match < 0)

	schan = to_shdma_chan(chan);

	sdev = to_shdma_dev(chan->device);



	/*

	 * For DT, the schan->slave_id field is generated by the

	 * set_slave function from the slave ID that is passed in

	 * from xlate. For the non-DT case, the slave ID is

	 * directly passed into the filter function by the driver

	 */

	if (schan->dev->of_node) {

		ret = sdev->ops->set_slave(schan, slave_id, 0, true);

		if (ret < 0)

			return false;



		schan->real_slave_id = schan->slave_id;

		return true;

	}



	if (slave_id < 0) {

		/* No slave requested - arbitrary channel */

		dev_warn(sdev->dma_dev.dev, "invalid slave ID passed to dma_request_slave\n");

		return true;

	}



	schan = to_shdma_chan(chan);

	if (!schan->dev->of_node && match >= slave_num)

	if (slave_id >= slave_num)

		return false;



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

	ret = sdev->ops->set_slave(schan, match, 0, true);

	ret = sdev->ops->set_slave(schan, slave_id, 0, true);

	if (ret < 0)

		return false;



	schan->real_slave_id = slave_id;



	return true;

}

EXPORT_SYMBOL(shdma_chan_filter);
@@ -452,6 +474,8 @@ static void shdma_free_chan_resources(struct dma_chan *chan) 
		chan->private = NULL;

	}



	schan->real_slave_id = 0;



	spin_lock_irq(&schan->chan_lock);



	list_splice_init(&schan->ld_free, &list);
@@ -764,11 +788,20 @@ static int shdma_config(struct dma_chan *chan, 
	 */

	if (!config)

		return -EINVAL;



	/*

	 * overriding the slave_id through dma_slave_config is deprecated,

	 * but possibly some out-of-tree drivers still do it.

	 */

	if (WARN_ON_ONCE(config->slave_id &&

			 config->slave_id != schan->real_slave_id))

		schan->real_slave_id = config->slave_id;



	/*

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

	 * channel, while using it...

	 */

	return shdma_setup_slave(schan, config->slave_id,

	return shdma_setup_slave(schan,

				 config->direction == DMA_DEV_TO_MEM ?

				 config->src_addr : config->dst_addr);

}

include/linux/shdma-base.h

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ struct shdma_chan { 
	int id;				/* Raw id of this channel */

	int irq;			/* Channel IRQ */

	int slave_id;			/* Client ID for slave DMA */

	int real_slave_id;		/* argument passed to filter function */

	int hw_req;			/* DMA request line for slave DMA - same

					 * as MID/RID, used with DT */

	enum shdma_pm_state pm_state;