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authorMaxime Ripard <maxime.ripard@free-electrons.com>2015-05-07 17:38:10 +0200
committerVinod Koul <vinod.koul@intel.com>2015-05-18 10:59:35 +0530
commit0d0ee751f7f7cd7d44eeb596f3b430ed0b178e07 (patch)
treec41357b2ee6a55490b52cf2b3b81fb8b3f595868 /drivers/dma
parentf0816a36887b5b6acb387d8a554c5f5ed4069d33 (diff)
downloadlinux-0d0ee751f7f7cd7d44eeb596f3b430ed0b178e07.tar.bz2
dmaengine: xdmac: Rework the chaining logic
So far, we were setting the NDE bit in our descriptors through some logic to try to see if we were the last descriptor in the chain. However, that was turning out to be rather complex to get right, while this information is also available when we actually chain a new descriptor after an already existing one. Simplify this by never setting NDE unless when we actually chain a descriptor. 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>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/at_xdmac.c41
1 files changed, 20 insertions, 21 deletions
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index cbeadeeed9c0..0144a935b8f2 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -471,6 +471,20 @@ static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
return desc;
}
+static void at_xdmac_queue_desc(struct dma_chan *chan,
+ struct at_xdmac_desc *prev,
+ struct at_xdmac_desc *desc)
+{
+ if (!prev || !desc)
+ return;
+
+ prev->lld.mbr_nda = desc->tx_dma_desc.phys;
+ prev->lld.mbr_ubc |= AT_XDMAC_MBR_UBC_NDE;
+
+ dev_dbg(chan2dev(chan), "%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
+ __func__, prev, &prev->lld.mbr_nda);
+}
+
static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
struct of_dma *of_dma)
{
@@ -627,19 +641,14 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2 /* next descriptor view */
| AT_XDMAC_MBR_UBC_NDEN /* next descriptor dst parameter update */
| AT_XDMAC_MBR_UBC_NSEN /* next descriptor src parameter update */
- | (i == sg_len - 1 ? 0 : AT_XDMAC_MBR_UBC_NDE) /* descriptor fetch */
| (len >> fixed_dwidth); /* microblock length */
dev_dbg(chan2dev(chan),
"%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
__func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
/* Chain lld. */
- if (prev) {
- prev->lld.mbr_nda = desc->tx_dma_desc.phys;
- dev_dbg(chan2dev(chan),
- "%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
- __func__, prev, &prev->lld.mbr_nda);
- }
+ if (prev)
+ at_xdmac_queue_desc(chan, prev, desc);
prev = desc;
if (!first)
@@ -714,7 +723,6 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV1
| AT_XDMAC_MBR_UBC_NDEN
| AT_XDMAC_MBR_UBC_NSEN
- | AT_XDMAC_MBR_UBC_NDE
| period_len >> at_xdmac_get_dwidth(desc->lld.mbr_cfg);
dev_dbg(chan2dev(chan),
@@ -722,12 +730,8 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
__func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc);
/* Chain lld. */
- if (prev) {
- prev->lld.mbr_nda = desc->tx_dma_desc.phys;
- dev_dbg(chan2dev(chan),
- "%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
- __func__, prev, &prev->lld.mbr_nda);
- }
+ if (prev)
+ at_xdmac_queue_desc(chan, prev, desc);
prev = desc;
if (!first)
@@ -850,7 +854,6 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV2
| AT_XDMAC_MBR_UBC_NDEN
| AT_XDMAC_MBR_UBC_NSEN
- | (remaining_size ? AT_XDMAC_MBR_UBC_NDE : 0)
| ublen;
desc->lld.mbr_cfg = chan_cc;
@@ -859,12 +862,8 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
__func__, &desc->lld.mbr_sa, &desc->lld.mbr_da, desc->lld.mbr_ubc, desc->lld.mbr_cfg);
/* Chain lld. */
- if (prev) {
- prev->lld.mbr_nda = desc->tx_dma_desc.phys;
- dev_dbg(chan2dev(chan),
- "%s: chain lld: prev=0x%p, mbr_nda=0x%08x\n",
- __func__, prev, prev->lld.mbr_nda);
- }
+ if (prev)
+ at_xdmac_queue_desc(chan, prev, desc);
prev = desc;
if (!first)