[PATCH 4.14 161/496] dmaengine: rcar-dmac: fix max_chunk_size for R-Car Gen3

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 06:48:38 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>

[ Upstream commit d716d9b702bb759dd6fb50804f10a174bd156d71 ]

According to R-Car Gen3 Rev.0.80 manual, the DMATCR can be set to
16,777,215 as maximum. So, this patch fixes the max_chunk_size for
safety on all of SoCs. Otherwise, a system may hang if the DMATCR
is set to 0 on R-Car Gen3.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -880,7 +880,7 @@ rcar_dmac_chan_prep_sg(struct rcar_dmac_

rcar_dmac_chan_configure_desc(chan, desc);

- max_chunk_size = (RCAR_DMATCR_MASK + 1) << desc->xfer_shift;
+ max_chunk_size = RCAR_DMATCR_MASK << desc->xfer_shift;

/*
* Allocate and fill the transfer chunk descriptors. We own the only