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Subject[PATCH 3/3] dmaengine: at_xdmac: only monitor overflow errors for peripheral xfer
Date
The overflow error flag (ROI: Request Overflow Error) is only relevant
for the case when the channel handles a peripheral synchronized transfer.
Not in the case of memory to memory transfer where there is no hardware
request signal.

Remove the use of this interrupt source in such a case. It's based on
the first descriptor which holds the configuration for the whole
linked list transfer.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
drivers/dma/at_xdmac.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index ec7a29d8e448..b558a23ffbc2 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -308,6 +308,11 @@ static inline int at_xdmac_csize(u32 maxburst)
return csize;
};

+static inline bool at_xdmac_chan_is_peripheral_xfer(u32 cfg)
+{
+ return cfg & AT_XDMAC_CC_TYPE_PER_TRAN;
+}
+
static inline u8 at_xdmac_get_dwidth(u32 cfg)
{
return (cfg & AT_XDMAC_CC_DWIDTH_MASK) >> AT_XDMAC_CC_DWIDTH_OFFSET;
@@ -389,7 +394,13 @@ static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
at_xdmac_chan_read(atchan, AT_XDMAC_CUBC));

at_xdmac_chan_write(atchan, AT_XDMAC_CID, 0xffffffff);
- reg = AT_XDMAC_CIE_RBEIE | AT_XDMAC_CIE_WBEIE | AT_XDMAC_CIE_ROIE;
+ reg = AT_XDMAC_CIE_RBEIE | AT_XDMAC_CIE_WBEIE;
+ /*
+ * Request Overflow Error is only for peripheral synchronized transfers
+ */
+ if (at_xdmac_chan_is_peripheral_xfer(first->lld.mbr_cfg))
+ reg |= AT_XDMAC_CIE_ROIE;
+
/*
* There is no end of list when doing cyclic dma, we need to get
* an interrupt after each periods.
--
2.17.1
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