Commit c3c860b3 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: mite: tidy up mite dma channel request/release 



For aesthetics, make the actual "request" function static and change
mite_request_channel_in_range() into a wrapper that calls the internal
function. Change the inline function that requests any free channel
into an export that also calls the internal function.

Move the functions to a more logical spot in the code and add docbook
comments for the exported functions.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fc532423

drivers/staging/comedi/drivers/mite.c

+84 −53
Original line number Diff line number Diff line
@@ -228,59 +228,6 @@ static unsigned int mite_fifo_size(struct mite *mite, unsigned int channel) 
	return empty_count + full_count;

}



struct mite_channel *mite_request_channel_in_range(struct mite *mite,

						   struct mite_ring *ring,

						   unsigned int min_channel,

						   unsigned int max_channel)

{

	struct mite_channel *mite_chan = NULL;

	unsigned long flags;

	int i;



	/*

	 * spin lock so mite_release_channel can be called safely

	 * from interrupts

	 */

	spin_lock_irqsave(&mite->lock, flags);

	for (i = min_channel; i <= max_channel; ++i) {

		mite_chan = &mite->channels[i];

		if (!mite_chan->ring) {

			mite_chan->ring = ring;

			break;

		}

		mite_chan = NULL;

	}

	spin_unlock_irqrestore(&mite->lock, flags);

	return mite_chan;

}

EXPORT_SYMBOL_GPL(mite_request_channel_in_range);



void mite_release_channel(struct mite_channel *mite_chan)

{

	struct mite *mite = mite_chan->mite;

	unsigned long flags;



	/* spin lock to prevent races with mite_request_channel */

	spin_lock_irqsave(&mite->lock, flags);

	if (mite_chan->ring) {

		mite_dma_disarm(mite_chan);

		mite_dma_reset(mite_chan);

		/*

		 * disable all channel's interrupts (do it after disarm/reset so

		 * MITE_CHCR reg isn't changed while dma is still active!)

		 */

		writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |

		       CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |

		       CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |

		       CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,

		       mite->mmio + MITE_CHCR(mite_chan->channel));

		mite_chan->ring = NULL;

		mmiowb();

	}

	spin_unlock_irqrestore(&mite->lock, flags);

}

EXPORT_SYMBOL_GPL(mite_release_channel);



void mite_dma_arm(struct mite_channel *mite_chan)

{

	struct mite *mite = mite_chan->mite;
@@ -585,6 +532,90 @@ int mite_done(struct mite_channel *mite_chan) 
}

EXPORT_SYMBOL_GPL(mite_done);



static struct mite_channel *__mite_request_channel(struct mite *mite,

						   struct mite_ring *ring,

						   unsigned int min_channel,

						   unsigned int max_channel)

{

	struct mite_channel *mite_chan = NULL;

	unsigned long flags;

	int i;



	/*

	 * spin lock so mite_release_channel can be called safely

	 * from interrupts

	 */

	spin_lock_irqsave(&mite->lock, flags);

	for (i = min_channel; i <= max_channel; ++i) {

		mite_chan = &mite->channels[i];

		if (!mite_chan->ring) {

			mite_chan->ring = ring;

			break;

		}

		mite_chan = NULL;

	}

	spin_unlock_irqrestore(&mite->lock, flags);

	return mite_chan;

}



/**

 * mite_request_channel_in_range() - Request a MITE dma channel.

 * @mite: MITE device.

 * @ring: MITE dma ring.

 * @min_channel: minimum channel index to use.

 * @max_channel: maximum channel index to use.

 */

struct mite_channel *mite_request_channel_in_range(struct mite *mite,

						   struct mite_ring *ring,

						   unsigned int min_channel,

						   unsigned int max_channel)

{

	return __mite_request_channel(mite, ring, min_channel, max_channel);

}

EXPORT_SYMBOL_GPL(mite_request_channel_in_range);



/**

 * mite_request_channel() - Request a MITE dma channel.

 * @mite: MITE device.

 * @ring: MITE dma ring.

 */

struct mite_channel *mite_request_channel(struct mite *mite,

					  struct mite_ring *ring)

{

	return __mite_request_channel(mite, ring, 0, mite->num_channels - 1);

}

EXPORT_SYMBOL_GPL(mite_request_channel);



/**

 * mite_release_channel() - Release a MITE dma channel.

 * @mite_chan: MITE dma channel.

 */

void mite_release_channel(struct mite_channel *mite_chan)

{

	struct mite *mite = mite_chan->mite;

	unsigned long flags;



	/* spin lock to prevent races with mite_request_channel */

	spin_lock_irqsave(&mite->lock, flags);

	if (mite_chan->ring) {

		mite_dma_disarm(mite_chan);

		mite_dma_reset(mite_chan);

		/*

		 * disable all channel's interrupts (do it after disarm/reset so

		 * MITE_CHCR reg isn't changed while dma is still active!)

		 */

		writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |

		       CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |

		       CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |

		       CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,

		       mite->mmio + MITE_CHCR(mite_chan->channel));

		mite_chan->ring = NULL;

		mmiowb();

	}

	spin_unlock_irqrestore(&mite->lock, flags);

}

EXPORT_SYMBOL_GPL(mite_release_channel);



/**

 * mite_init_ring_descriptors() - Initialize a MITE dma ring descriptors.

 * @ring: MITE dma ring.

drivers/staging/comedi/drivers/mite.h

+7 −14
Original line number Diff line number Diff line
@@ -60,20 +60,6 @@ struct mite { 
	spinlock_t lock;

};



struct mite_channel *mite_request_channel_in_range(struct mite *,

						   struct mite_ring *,

						   unsigned int min_channel,

						   unsigned int max_channel);



static inline struct mite_channel *mite_request_channel(struct mite *mite,

							struct mite_ring *ring)

{

	return mite_request_channel_in_range(mite, ring, 0,

					     mite->num_channels - 1);

}



void mite_release_channel(struct mite_channel *mite_chan);



void mite_dma_arm(struct mite_channel *mite_chan);

void mite_dma_disarm(struct mite_channel *mite_chan);

void mite_sync_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s);
@@ -85,6 +71,13 @@ int mite_done(struct mite_channel *mite_chan); 
void mite_prep_dma(struct mite_channel *mite_chan,

		   unsigned int num_device_bits, unsigned int num_memory_bits);



struct mite_channel *mite_request_channel_in_range(struct mite *,

						   struct mite_ring *,

						   unsigned int min_channel,

						   unsigned int max_channel);

struct mite_channel *mite_request_channel(struct mite *, struct mite_ring *);

void mite_release_channel(struct mite_channel *);



int mite_init_ring_descriptors(struct mite_ring *, struct comedi_subdevice *,

			       unsigned int nbytes);

int mite_buf_change(struct mite_ring *, struct comedi_subdevice *);

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