Commit fc532423 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: mite: move the mite ring functions 



For aesthetics, move the functions that allocate/free and initialize
the mite dma ring. They are currently kind of scattered around the
code.

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 a2163cc3

drivers/staging/comedi/drivers/mite.c

+145 −129
Original line number Diff line number Diff line
@@ -228,49 +228,6 @@ static unsigned int mite_fifo_size(struct mite *mite, unsigned int channel) 
	return empty_count + full_count;

}



struct mite_ring *mite_alloc_ring(struct mite *mite)

{

	struct mite_ring *ring;



	ring = kmalloc(sizeof(*ring), GFP_KERNEL);

	if (!ring)

		return NULL;

	ring->hw_dev = get_device(&mite->pcidev->dev);

	if (!ring->hw_dev) {

		kfree(ring);

		return NULL;

	}

	ring->n_links = 0;

	ring->descs = NULL;

	ring->dma_addr = 0;

	return ring;

};

EXPORT_SYMBOL_GPL(mite_alloc_ring);



static void mite_free_dma_descs(struct mite_ring *ring)

{

	struct mite_dma_desc *descs = ring->descs;



	if (descs) {

		dma_free_coherent(ring->hw_dev,

				  ring->n_links * sizeof(*descs),

				  descs, ring->dma_addr);

		ring->descs = NULL;

		ring->dma_addr = 0;

		ring->n_links = 0;

	}

}



void mite_free_ring(struct mite_ring *ring)

{

	if (ring) {

		mite_free_dma_descs(ring);

		put_device(ring->hw_dev);

		kfree(ring);

	}

};

EXPORT_SYMBOL_GPL(mite_free_ring);



struct mite_channel *mite_request_channel_in_range(struct mite *mite,

						   struct mite_ring *ring,

						   unsigned int min_channel,
@@ -343,92 +300,6 @@ void mite_dma_arm(struct mite_channel *mite_chan) 
}

EXPORT_SYMBOL_GPL(mite_dma_arm);



/**************************************/



int mite_buf_change(struct mite_ring *ring,

		    struct comedi_subdevice *s)

{

	struct comedi_async *async = s->async;

	struct mite_dma_desc *descs;

	unsigned int n_links;



	mite_free_dma_descs(ring);



	if (async->prealloc_bufsz == 0)

		return 0;



	n_links = async->prealloc_bufsz >> PAGE_SHIFT;



	descs = dma_alloc_coherent(ring->hw_dev,

				   n_links * sizeof(*descs),

				   &ring->dma_addr, GFP_KERNEL);

	if (!descs) {

		dev_err(s->device->class_dev,

			"mite: ring buffer allocation failed\n");

		return -ENOMEM;

	}

	ring->descs = descs;

	ring->n_links = n_links;



	return mite_init_ring_descriptors(ring, s, n_links << PAGE_SHIFT);

}

EXPORT_SYMBOL_GPL(mite_buf_change);



/*

 * initializes the ring buffer descriptors to provide correct DMA transfer links

 * to the exact amount of memory required.  When the ring buffer is allocated in

 * mite_buf_change, the default is to initialize the ring to refer to the entire

 * DMA data buffer.  A command may call this function later to re-initialize and

 * shorten the amount of memory that will be transferred.

 */

int mite_init_ring_descriptors(struct mite_ring *ring,

			       struct comedi_subdevice *s,

			       unsigned int nbytes)

{

	struct comedi_async *async = s->async;

	struct mite_dma_desc *desc = NULL;

	unsigned int n_full_links = nbytes >> PAGE_SHIFT;

	unsigned int remainder = nbytes % PAGE_SIZE;

	int i;



	dev_dbg(s->device->class_dev,

		"mite: init ring buffer to %u bytes\n", nbytes);



	if ((n_full_links + (remainder > 0 ? 1 : 0)) > ring->n_links) {

		dev_err(s->device->class_dev,

			"mite: ring buffer too small for requested init\n");

		return -ENOMEM;

	}



	/* We set the descriptors for all full links. */

	for (i = 0; i < n_full_links; ++i) {

		desc = &ring->descs[i];

		desc->count = cpu_to_le32(PAGE_SIZE);

		desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);

		desc->next = cpu_to_le32(ring->dma_addr +

					 (i + 1) * sizeof(*desc));

	}



	/* the last link is either a remainder or was a full link. */

	if (remainder > 0) {

		desc = &ring->descs[i];

		/* set the lesser count for the remainder link */

		desc->count = cpu_to_le32(remainder);

		desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);

	}



	/* Assign the last link->next to point back to the head of the list. */

	desc->next = cpu_to_le32(ring->dma_addr);



	/*

	 * barrier is meant to insure that all the writes to the dma descriptors

	 * have completed before the dma controller is commanded to read them

	 */

	smp_wmb();

	return 0;

}

EXPORT_SYMBOL_GPL(mite_init_ring_descriptors);



void mite_prep_dma(struct mite_channel *mite_chan,

		   unsigned int num_device_bits, unsigned int num_memory_bits)

{
@@ -714,6 +585,151 @@ int mite_done(struct mite_channel *mite_chan) 
}

EXPORT_SYMBOL_GPL(mite_done);



/**

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

 * @ring: MITE dma ring.

 * @s: COMEDI subdevice.

 * @nbytes: the size of the dma ring (in bytes).

 *

 * Initializes the ring buffer descriptors to provide correct DMA transfer

 * links to the exact amount of memory required. When the ring buffer is

 * allocated by mite_buf_change(), the default is to initialize the ring

 * to refer to the entire DMA data buffer. A command may call this function

 * later to re-initialize and shorten the amount of memory that will be

 * transferred.

 */

int mite_init_ring_descriptors(struct mite_ring *ring,

			       struct comedi_subdevice *s,

			       unsigned int nbytes)

{

	struct comedi_async *async = s->async;

	struct mite_dma_desc *desc = NULL;

	unsigned int n_full_links = nbytes >> PAGE_SHIFT;

	unsigned int remainder = nbytes % PAGE_SIZE;

	int i;



	dev_dbg(s->device->class_dev,

		"mite: init ring buffer to %u bytes\n", nbytes);



	if ((n_full_links + (remainder > 0 ? 1 : 0)) > ring->n_links) {

		dev_err(s->device->class_dev,

			"mite: ring buffer too small for requested init\n");

		return -ENOMEM;

	}



	/* We set the descriptors for all full links. */

	for (i = 0; i < n_full_links; ++i) {

		desc = &ring->descs[i];

		desc->count = cpu_to_le32(PAGE_SIZE);

		desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);

		desc->next = cpu_to_le32(ring->dma_addr +

					 (i + 1) * sizeof(*desc));

	}



	/* the last link is either a remainder or was a full link. */

	if (remainder > 0) {

		desc = &ring->descs[i];

		/* set the lesser count for the remainder link */

		desc->count = cpu_to_le32(remainder);

		desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);

	}



	/* Assign the last link->next to point back to the head of the list. */

	desc->next = cpu_to_le32(ring->dma_addr);



	/*

	 * barrier is meant to insure that all the writes to the dma descriptors

	 * have completed before the dma controller is commanded to read them

	 */

	smp_wmb();

	return 0;

}

EXPORT_SYMBOL_GPL(mite_init_ring_descriptors);



static void mite_free_dma_descs(struct mite_ring *ring)

{

	struct mite_dma_desc *descs = ring->descs;



	if (descs) {

		dma_free_coherent(ring->hw_dev,

				  ring->n_links * sizeof(*descs),

				  descs, ring->dma_addr);

		ring->descs = NULL;

		ring->dma_addr = 0;

		ring->n_links = 0;

	}

}



/**

 * mite_buf_change() - COMEDI subdevice (*buf_change) for a MITE dma ring.

 * @ring: MITE dma ring.

 * @s: COMEDI subdevice.

 */

int mite_buf_change(struct mite_ring *ring, struct comedi_subdevice *s)

{

	struct comedi_async *async = s->async;

	struct mite_dma_desc *descs;

	unsigned int n_links;



	mite_free_dma_descs(ring);



	if (async->prealloc_bufsz == 0)

		return 0;



	n_links = async->prealloc_bufsz >> PAGE_SHIFT;



	descs = dma_alloc_coherent(ring->hw_dev,

				   n_links * sizeof(*descs),

				   &ring->dma_addr, GFP_KERNEL);

	if (!descs) {

		dev_err(s->device->class_dev,

			"mite: ring buffer allocation failed\n");

		return -ENOMEM;

	}

	ring->descs = descs;

	ring->n_links = n_links;



	return mite_init_ring_descriptors(ring, s, n_links << PAGE_SHIFT);

}

EXPORT_SYMBOL_GPL(mite_buf_change);



/**

 * mite_alloc_ring() - Allocate a MITE dma ring.

 * @mite: MITE device.

 */

struct mite_ring *mite_alloc_ring(struct mite *mite)

{

	struct mite_ring *ring;



	ring = kmalloc(sizeof(*ring), GFP_KERNEL);

	if (!ring)

		return NULL;

	ring->hw_dev = get_device(&mite->pcidev->dev);

	if (!ring->hw_dev) {

		kfree(ring);

		return NULL;

	}

	ring->n_links = 0;

	ring->descs = NULL;

	ring->dma_addr = 0;

	return ring;

}

EXPORT_SYMBOL_GPL(mite_alloc_ring);



/**

 * mite_free_ring() - Free a MITE dma ring and its descriptors.

 * @ring: MITE dma ring.

 */

void mite_free_ring(struct mite_ring *ring)

{

	if (ring) {

		mite_free_dma_descs(ring);

		put_device(ring->hw_dev);

		kfree(ring);

	}

}

EXPORT_SYMBOL_GPL(mite_free_ring);



static int mite_setup(struct comedi_device *dev, struct mite *mite,

		      bool use_win1)

{

drivers/staging/comedi/drivers/mite.h

+5 −3
Original line number Diff line number Diff line
@@ -60,8 +60,6 @@ struct mite { 
	spinlock_t lock;

};



struct mite_ring *mite_alloc_ring(struct mite *);

void mite_free_ring(struct mite_ring *ring);

struct mite_channel *mite_request_channel_in_range(struct mite *,

						   struct mite_ring *,

						   unsigned int min_channel,
@@ -86,9 +84,13 @@ 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);

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



int mite_init_ring_descriptors(struct mite_ring *, struct comedi_subdevice *,

			       unsigned int nbytes);

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



struct mite_ring *mite_alloc_ring(struct mite *);

void mite_free_ring(struct mite_ring *);



struct mite *mite_attach(struct comedi_device *, bool use_win1);

void mite_detach(struct mite *);

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