[PATCH v2 02/15] dmaengine: dw: clear LLP_[SD]_EN bits in last descriptor of a chain

Andy Shevchenko
2016-02-22T16:04:03Z

From: Mans Rullgard <mans@mansr.com>

The datasheet requires that the LLP_[SD]_EN bits be cleared whenever
LLP.LOC is zero, i.e. in the last descriptor of a multi-block chain.
Make the driver do this.

Signed-off-by: Mans Rullgard <mans@mansr.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/dma/dw/core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index cd7616e..4a823f4 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -763,6 +763,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
lli_set(prev, ctllo, DWC_CTLL_INT_EN);

prev->lli.llp = 0;
+ lli_clear(prev, ctllo, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
first->txd.flags = flags;
first->total_len = len;

@@ -922,6 +923,7 @@ slave_sg_fromdev_fill_desc:
lli_set(prev, ctllo, DWC_CTLL_INT_EN);

prev->lli.llp = 0;
+ lli_clear(prev, ctllo, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
first->total_len = total_len;

return &first->txd;
--
2.7.0