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dmaengine: xdmac: Add scatter gathered memset support 

The XDMAC also supports memset operations over discontiguous areas. Add the
necessary logic to support this.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Maxime Ripard 2015-07-06 12:19:24 +02:00 committed by Vinod Koul
parent 50c7cd2bd3
commit 67a6eedc4d
1 changed files with 165 additions and 1 deletions
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166
drivers/dma/at_xdmac.c
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@ -1133,7 +1133,7 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan,
* SAMA5D4x), so we can use the same interface for source and dest,
* that solves the fact we don't know the direction.
*/
u32 chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM
u32 chan_cc = AT_XDMAC_CC_DAM_UBS_AM
| AT_XDMAC_CC_SAM_INCREMENTED_AM
| AT_XDMAC_CC_DIF(0)
| AT_XDMAC_CC_SIF(0)
@ -1201,6 +1201,168 @@ at_xdmac_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
return &desc->tx_dma_desc;
}
static struct dma_async_tx_descriptor *
at_xdmac_prep_dma_memset_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, int value,
unsigned long flags)
{
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
struct at_xdmac_desc *desc, *pdesc = NULL,
*ppdesc = NULL, *first = NULL;
struct scatterlist *sg, *psg = NULL, *ppsg = NULL;
size_t stride = 0, pstride = 0, len = 0;
int i;
if (!sgl)
return NULL;
dev_dbg(chan2dev(chan), "%s: sg_len=%d, value=0x%x, flags=0x%lx\n",
__func__, sg_len, value, flags);
/* Prepare descriptors. */
for_each_sg(sgl, sg, sg_len, i) {
dev_dbg(chan2dev(chan), "%s: dest=0x%08x, len=%d, pattern=0x%x, flags=0x%lx\n",
__func__, sg_dma_address(sg), sg_dma_len(sg),
value, flags);
desc = at_xdmac_memset_create_desc(chan, atchan,
sg_dma_address(sg),
sg_dma_len(sg),
value);
if (!desc && first)
list_splice_init(&first->descs_list,
&atchan->free_descs_list);
if (!first)
first = desc;
/* Update our strides */
pstride = stride;
if (psg)
stride = sg_dma_address(sg) -
(sg_dma_address(psg) + sg_dma_len(psg));
/*
* The scatterlist API gives us only the address and
* length of each elements.
*
* Unfortunately, we don't have the stride, which we
* will need to compute.
*
* That make us end up in a situation like this one:
* len stride len stride len
* +-------+ +-------+ +-------+
* | N-2 | | N-1 | | N |
* +-------+ +-------+ +-------+
*
* We need all these three elements (N-2, N-1 and N)
* to actually take the decision on whether we need to
* queue N-1 or reuse N-2.
*
* We will only consider N if it is the last element.
*/
if (ppdesc && pdesc) {
if ((stride == pstride) &&
(sg_dma_len(ppsg) == sg_dma_len(psg))) {
dev_dbg(chan2dev(chan),
"%s: desc 0x%p can be merged with desc 0x%p\n",
__func__, pdesc, ppdesc);
/*
* Increment the block count of the
* N-2 descriptor
*/
at_xdmac_increment_block_count(chan, ppdesc);
ppdesc->lld.mbr_dus = stride;
/*
* Put back the N-1 descriptor in the
* free descriptor list
*/
list_add_tail(&pdesc->desc_node,
&atchan->free_descs_list);
/*
* Make our N-1 descriptor pointer
* point to the N-2 since they were
* actually merged.
*/
pdesc = ppdesc;
/*
* Rule out the case where we don't have
* pstride computed yet (our second sg
* element)
*
* We also want to catch the case where there
* would be a negative stride,
*/
} else if (pstride ||
sg_dma_address(sg) < sg_dma_address(psg)) {
/*
* Queue the N-1 descriptor after the
* N-2
*/
at_xdmac_queue_desc(chan, ppdesc, pdesc);
/*
* Add the N-1 descriptor to the list
* of the descriptors used for this
* transfer
*/
list_add_tail(&desc->desc_node,
&first->descs_list);
dev_dbg(chan2dev(chan),
"%s: add desc 0x%p to descs_list 0x%p\n",
__func__, desc, first);
}
}
/*
* If we are the last element, just see if we have the
* same size than the previous element.
*
* If so, we can merge it with the previous descriptor
* since we don't care about the stride anymore.
*/
if ((i == (sg_len - 1)) &&
sg_dma_len(ppsg) == sg_dma_len(psg)) {
dev_dbg(chan2dev(chan),
"%s: desc 0x%p can be merged with desc 0x%p\n",
__func__, desc, pdesc);
/*
* Increment the block count of the N-1
* descriptor
*/
at_xdmac_increment_block_count(chan, pdesc);
pdesc->lld.mbr_dus = stride;
/*
* Put back the N descriptor in the free
* descriptor list
*/
list_add_tail(&desc->desc_node,
&atchan->free_descs_list);
}
/* Update our descriptors */
ppdesc = pdesc;
pdesc = desc;
/* Update our scatter pointers */
ppsg = psg;
psg = sg;
len += sg_dma_len(sg);
}
first->tx_dma_desc.cookie = -EBUSY;
first->tx_dma_desc.flags = flags;
first->xfer_size = len;
return &first->tx_dma_desc;
}
static enum dma_status
at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
struct dma_tx_state *txstate)
@ -1734,6 +1896,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
dma_cap_set(DMA_INTERLEAVE, atxdmac->dma.cap_mask);
dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
dma_cap_set(DMA_MEMSET, atxdmac->dma.cap_mask);
dma_cap_set(DMA_MEMSET_SG, atxdmac->dma.cap_mask);
dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
/*
* Without DMA_PRIVATE the driver is not able to allocate more than
@ -1749,6 +1912,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
atxdmac->dma.device_prep_interleaved_dma = at_xdmac_prep_interleaved;
atxdmac->dma.device_prep_dma_memcpy = at_xdmac_prep_dma_memcpy;
atxdmac->dma.device_prep_dma_memset = at_xdmac_prep_dma_memset;
atxdmac->dma.device_prep_dma_memset_sg = at_xdmac_prep_dma_memset_sg;
atxdmac->dma.device_prep_slave_sg = at_xdmac_prep_slave_sg;
atxdmac->dma.device_config = at_xdmac_device_config;
atxdmac->dma.device_pause = at_xdmac_device_pause;