rapidio/tsi721_dma: rework scatter-gather list handling

Rework Tsi721 RapidIO DMA engine support to allow handling data
scatter/gather lists longer than number of hardware buffer descriptors in
the DMA channel's descriptor list.

The current implementation of Tsi721 DMA transfers requires that number of
entries in a scatter/gather list provided by a caller of
dmaengine_prep_rio_sg() should not exceed number of allocated hardware
buffer descriptors.

This patch removes the limitation by processing long scatter/gather lists
by sections that can be transferred using hardware descriptor ring of
configured size.  It also introduces a module parameter
"dma_desc_per_channel" to allow run-time configuration of Tsi721 hardware
buffer descriptor rings.

Signed-off-by: Alexandre Bounine <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Andre van Herk <[email protected]>
Cc: Stef van Os <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Dan Williams <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions