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Commit c1433041 authored by Ira Snyder's avatar Ira Snyder Committed by Dan Williams
Browse files

fsldma: implement support for scatterlist to scatterlist copy 



Now that the DMAEngine API has support for scatterlist to scatterlist
copy, implement support for the Freescale DMA controller.

Signed-off-by: default avatarIra W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent a86ee03c

drivers/dma/fsldma.c

+125 −3
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ 
#include <asm/fsldma.h>

#include "fsldma.h"



static const char msg_ld_oom[] = "No free memory for link descriptor\n";



static void dma_init(struct fsldma_chan *chan)

{

	/* Reset the channel */
@@ -499,7 +501,7 @@ fsl_dma_prep_interrupt(struct dma_chan *dchan, unsigned long flags) 


	new = fsl_dma_alloc_descriptor(chan);

	if (!new) {

		dev_err(chan->dev, "No free memory for link descriptor\n");

		dev_err(chan->dev, msg_ld_oom);

		return NULL;

	}
@@ -536,8 +538,7 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy( 
		/* Allocate the link descriptor from DMA pool */

		new = fsl_dma_alloc_descriptor(chan);

		if (!new) {

			dev_err(chan->dev,

					"No free memory for link descriptor\n");

			dev_err(chan->dev, msg_ld_oom);

			goto fail;

		}

#ifdef FSL_DMA_LD_DEBUG
@@ -583,6 +584,125 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy( 
	return NULL;

}



static struct dma_async_tx_descriptor *fsl_dma_prep_sg(struct dma_chan *dchan,

	struct scatterlist *dst_sg, unsigned int dst_nents,

	struct scatterlist *src_sg, unsigned int src_nents,

	unsigned long flags)

{

	struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL;

	struct fsldma_chan *chan = to_fsl_chan(dchan);

	size_t dst_avail, src_avail;

	dma_addr_t dst, src;

	size_t len;



	/* basic sanity checks */

	if (dst_nents == 0 || src_nents == 0)

		return NULL;



	if (dst_sg == NULL || src_sg == NULL)

		return NULL;



	/*

	 * TODO: should we check that both scatterlists have the same

	 * TODO: number of bytes in total? Is that really an error?

	 */



	/* get prepared for the loop */

	dst_avail = sg_dma_len(dst_sg);

	src_avail = sg_dma_len(src_sg);



	/* run until we are out of scatterlist entries */

	while (true) {



		/* create the largest transaction possible */

		len = min_t(size_t, src_avail, dst_avail);

		len = min_t(size_t, len, FSL_DMA_BCR_MAX_CNT);

		if (len == 0)

			goto fetch;



		dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;

		src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;



		/* allocate and populate the descriptor */

		new = fsl_dma_alloc_descriptor(chan);

		if (!new) {

			dev_err(chan->dev, msg_ld_oom);

			goto fail;

		}

#ifdef FSL_DMA_LD_DEBUG

		dev_dbg(chan->dev, "new link desc alloc %p\n", new);

#endif



		set_desc_cnt(chan, &new->hw, len);

		set_desc_src(chan, &new->hw, src);

		set_desc_dst(chan, &new->hw, dst);



		if (!first)

			first = new;

		else

			set_desc_next(chan, &prev->hw, new->async_tx.phys);



		new->async_tx.cookie = 0;

		async_tx_ack(&new->async_tx);

		prev = new;



		/* Insert the link descriptor to the LD ring */

		list_add_tail(&new->node, &first->tx_list);



		/* update metadata */

		dst_avail -= len;

		src_avail -= len;



fetch:

		/* fetch the next dst scatterlist entry */

		if (dst_avail == 0) {



			/* no more entries: we're done */

			if (dst_nents == 0)

				break;



			/* fetch the next entry: if there are no more: done */

			dst_sg = sg_next(dst_sg);

			if (dst_sg == NULL)

				break;



			dst_nents--;

			dst_avail = sg_dma_len(dst_sg);

		}



		/* fetch the next src scatterlist entry */

		if (src_avail == 0) {



			/* no more entries: we're done */

			if (src_nents == 0)

				break;



			/* fetch the next entry: if there are no more: done */

			src_sg = sg_next(src_sg);

			if (src_sg == NULL)

				break;



			src_nents--;

			src_avail = sg_dma_len(src_sg);

		}

	}



	new->async_tx.flags = flags; /* client is in control of this ack */

	new->async_tx.cookie = -EBUSY;



	/* Set End-of-link to the last link descriptor of new list */

	set_ld_eol(chan, new);



	return &first->async_tx;



fail:

	if (!first)

		return NULL;



	fsldma_free_desc_list_reverse(chan, &first->tx_list);

	return NULL;

}



/**

 * fsl_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction

 * @chan: DMA channel
@@ -1327,11 +1447,13 @@ static int __devinit fsldma_of_probe(struct platform_device *op, 


	dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask);

	dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask);

	dma_cap_set(DMA_SG, fdev->common.cap_mask);

	dma_cap_set(DMA_SLAVE, fdev->common.cap_mask);

	fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;

	fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;

	fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt;

	fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;

	fdev->common.device_prep_dma_sg = fsl_dma_prep_sg;

	fdev->common.device_tx_status = fsl_tx_status;

	fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;

	fdev->common.device_prep_slave_sg = fsl_dma_prep_slave_sg;