Commit d84f638b authored by Shawn Guo's avatar Shawn Guo
Browse files

dma: mxs-dma: move to generic device tree binding 



Update mxs-dma driver to adopt generic DMA device tree binding.  It
calls of_dma_controller_register() with mxs specific of_dma_xlate to
get the generic DMA device tree helper support.  Then DMA clients only
need to call dma_request_slave_channel() for requesting a DMA channel
from dmaengine.

The existing way of requesting channel, clients directly call
dma_request_channel(), still work there, and will be removed after
all mxs-dma clients get converted to generic DMA device tree helper.

Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
parent aaa20517

drivers/dma/mxs-dma.c

+66 −4
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/stmp_device.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_dma.h>



#include <asm/irq.h>
@@ -139,6 +140,8 @@ struct mxs_dma_engine { 
	struct dma_device		dma_device;

	struct device_dma_parameters	dma_parms;

	struct mxs_dma_chan		mxs_chans[MXS_DMA_CHANNELS];

	struct platform_device		*pdev;

	unsigned int			nr_channels;

};



struct mxs_dma_type {
@@ -350,9 +353,7 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan) 
	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;

	int ret;



	if (!data)

		return -EINVAL;



	if (data)

		mxs_chan->chan_irq = data->chan_irq;



	mxs_chan->ccw = dma_alloc_coherent(mxs_dma->dma_device.dev,
@@ -665,8 +666,55 @@ err_out: 
	return ret;

}



struct mxs_dma_filter_param {

	struct device_node *of_node;

	unsigned int chan_id;

};



static bool mxs_dma_filter_fn(struct dma_chan *chan, void *fn_param)

{

	struct mxs_dma_filter_param *param = fn_param;

	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);

	struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;

	int chan_irq;



	if (mxs_dma->dma_device.dev->of_node != param->of_node)

		return false;



	if (chan->chan_id != param->chan_id)

		return false;



	chan_irq = platform_get_irq(mxs_dma->pdev, param->chan_id);

	if (chan_irq < 0)

		return false;



	mxs_chan->chan_irq = chan_irq;



	return true;

}



struct dma_chan *mxs_dma_xlate(struct of_phandle_args *dma_spec,

			       struct of_dma *ofdma)

{

	struct mxs_dma_engine *mxs_dma = ofdma->of_dma_data;

	dma_cap_mask_t mask = mxs_dma->dma_device.cap_mask;

	struct mxs_dma_filter_param param;



	if (dma_spec->args_count != 1)

		return NULL;



	param.of_node = ofdma->of_node;

	param.chan_id = dma_spec->args[0];



	if (param.chan_id >= mxs_dma->nr_channels)

		return NULL;



	return dma_request_channel(mask, mxs_dma_filter_fn, &param);

}



static int __init mxs_dma_probe(struct platform_device *pdev)

{

	struct device_node *np = pdev->dev.of_node;

	const struct platform_device_id *id_entry;

	const struct of_device_id *of_id;

	const struct mxs_dma_type *dma_type;
@@ -678,6 +726,12 @@ static int __init mxs_dma_probe(struct platform_device *pdev) 
	if (!mxs_dma)

		return -ENOMEM;



	ret = of_property_read_u32(np, "dma-channels", &mxs_dma->nr_channels);

	if (ret) {

		dev_err(&pdev->dev, "failed to read dma-channels\n");

		return ret;

	}



	of_id = of_match_device(mxs_dma_dt_ids, &pdev->dev);

	if (of_id)

		id_entry = of_id->data;
@@ -723,6 +777,7 @@ static int __init mxs_dma_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	mxs_dma->pdev = pdev;

	mxs_dma->dma_device.dev = &pdev->dev;



	/* mxs_dma gets 65535 bytes maximum sg size */
@@ -743,6 +798,13 @@ static int __init mxs_dma_probe(struct platform_device *pdev) 
		return ret;

	}



	ret = of_dma_controller_register(np, mxs_dma_xlate, mxs_dma);

	if (ret) {

		dev_err(mxs_dma->dma_device.dev,

			"failed to register controller\n");

		dma_async_device_unregister(&mxs_dma->dma_device);

	}



	dev_info(mxs_dma->dma_device.dev, "initialized\n");



	return 0;

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