Brian Niebuhr bniebu...@gmail.com writes:
This patch fixes an issue where a DMA channel can erroneously process an
event generated by a previous transfer. A failure case is where DMA is
being used for SPI transmit and receive channels on OMAP L138. In this
case there is a single bit that controls all event generation from the
SPI peripheral. Therefore it is possible that between when edma_stop()
has been called for the transmit channel on a previous transfer and
edma_start() is called for the transmit channel on a subsequent transfer,
that a transmit event has been generated.
The fix is to clear events in edma_start(). This prevents false events
from being processed when events are enabled for that channel.
Signed-off-by: Brian Niebuhr bnieb...@efjohnson.com
Thanks, applying and queuing in davinci-fixes for v2.6.34-rc
Kevin
---
arch/arm/mach-davinci/dma.c |3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/arm/mach-davinci/dma.c b/arch/arm/mach-davinci/dma.c
index 5cd48fa..52c16ff 100644
--- a/arch/arm/mach-davinci/dma.c
+++ b/arch/arm/mach-davinci/dma.c
@@ -1290,7 +1290,8 @@ int edma_start(unsigned channel)
/* EDMA channel with event association */
pr_debug(EDMA: ER%d %08x\n, j,
edma_shadow0_read_array(ctlr, SH_ER, j));
- /* Clear any pending error */
+ /* Clear any pending event or error */
+ edma_write_array(ctlr, EDMA_ECR, j, mask);
edma_write_array(ctlr, EDMA_EMCR, j, mask);
/* Clear any SER */
edma_shadow0_write_array(ctlr, SH_SECR, j, mask);
--
1.6.3.3
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