From: Kuninori Morimoto <[email protected]> In descriptor mode, the descriptor running pointer is not maintained by the interrupt handler, thus, driver finds the running descriptor from the descriptor pointer field in the CHCRB register. But, CHCRB::DPTR indicates *next* descriptor pointer, not current. Thus, The residue calculation will be missed. This patch fixup it.
Signed-off-by: Kuninori Morimoto <[email protected]> --- drivers/dma/sh/rcar-dmac.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index d2cb4a0..ffcadca 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1293,6 +1293,9 @@ static unsigned int rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan, if (desc->hwdescs.use) { dptr = (rcar_dmac_chan_read(chan, RCAR_DMACHCRB) & RCAR_DMACHCRB_DPTR_MASK) >> RCAR_DMACHCRB_DPTR_SHIFT; + if (dptr == 0) + dptr = desc->nchunks; + dptr--; WARN_ON(dptr >= desc->nchunks); } else { running = desc->running; -- 1.9.1
