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fsldma: implement support for scatterlist to scatterlist copy

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

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Ira Snyder 2010-09-30 11:46:45 +00:00 committed by Dan Williams
parent a86ee03ce6
commit c14330417e
1 changed files with 125 additions and 3 deletions
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128
drivers/dma/fsldma.c
View file

@ -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;