of/device: Really only set bus DMA mask when appropriate

rmurphy-arm · robherring · commit 6778be4e5209 · 2018-11-08T12:44:34.000-06:00
of_dma_configure() was *supposed* to be following the same logic as acpi_dma_configure() and only setting bus_dma_mask if some range was specified by the firmware. However, it seems that subtlety got lost in the process of fitting it into the differently-shaped control flow, and as a result the force_dma==true case ends up always setting the bus mask to the 32-bit default, which is not what anyone wants. Make sure we only touch it if the DT actually said so. Fixes: 6c2fb2e ("of/device: Set bus DMA mask as appropriate") Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Reported-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi> Tested-by: John Stultz <john.stultz@linaro.org> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Robert Richter <robert.richter@cavium.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/device.c b/drivers/of/device.c
@@ -149,9 +149,11 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
 	 * set by the driver.
 	 */
 	mask = DMA_BIT_MASK(ilog2(dma_addr + size - 1) + 1);
-	dev->bus_dma_mask = mask;
 	dev->coherent_dma_mask &= mask;
 	*dev->dma_mask &= mask;
+	/* ...but only set bus mask if we found valid dma-ranges earlier */
+	if (!ret)
+		dev->bus_dma_mask = mask;
 
 	coherent = of_dma_is_coherent(np);
 	dev_dbg(dev, "device is%sdma coherent\n",
