davinci: edma: clear events in edma_start()

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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 <bniebuhr@efjohnson.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

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Brian Niebuhr 2010-03-09 16:48:03 -06:00 • committed by Kevin Hilman

parent 5eb2e891f0

commit bb17ef102b

1 changed files with 2 additions and 1 deletions

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arch/arm/mach-davinci/dma.c

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