Add an upper bound check for the MID/RID value passed from DT via the
DMA spec.
This avoids writing to reserved bits in the DMARS registers in case of
an out-of-range value in DT.
Suggested-by: Renesas BSP team via Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 72572320208dbb9a..73cf1053bed90244 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1644,8 +1644,11 @@ static struct dma_chan *rcar_dmac_of_xlate(struct of_phandle_args *dma_spec,
struct dma_chan *chan;
dma_cap_mask_t mask;
- if (dma_spec->args_count != 1)
+ if (dma_spec->args_count != 1 || dma_spec->args[0] > 0xff) {
+ pr_info("%s: invalid MID/RID 0x%x... for %pOF\n", __func__,
+ dma_spec->args[0], dma_spec->np);
return NULL;
+ }
/* Only slave DMA channels can be allocated via DT */
dma_cap_zero(mask);
--
2.17.1
