mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
* [PATCH 1/2] arm64: dts: tegra186: Add dma-ranges to avoid using bounce buffers
@ 2018-10-17  2:06 Krishna Reddy
  2018-10-17  2:06 ` [PATCH 2/2] arm64: dts: tegra186: Enable IOMMU for SDHCI Krishna Reddy
  0 siblings, 1 reply; 2+ messages in thread
From: Krishna Reddy @ 2018-10-17  2:06 UTC (permalink / raw)
  To: robh+dt, mark.rutland, thierry.reding, jonathanh, mperttunen, avienamo
  Cc: devicetree, linux-tegra, linux-kernel, Krishna Reddy

Add dma-ranges to avoid using DMA bounce buffers unnecessarily for
the devices that can address the physcial memory and don't
have SMMU enabled.

This also resolves the failures in attaching devices to IOMMU.
The following error is caused by the check in io-pgtable-arm.c, where
the dma address is expected to match the physical address for the IOMMU
devices that don't support coherent page table walking. Bounce buffer
usage is causing the mismatch and device add failure.

[    7.000461] arm-smmu 12000000.iommu: Cannot accommodate DMA
translation for IOMMU page tables
[    7.010513] iommu: Failed to add device 15200000.display to group 0:
-12

Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
---
 arch/arm64/boot/dts/nvidia/tegra186.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
index 2f3c8e2..230c0c8 100644
--- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
@@ -14,6 +14,7 @@
 	interrupt-parent = <&gic>;
 	#address-cells = <2>;
 	#size-cells = <2>;
+	dma-ranges = <0x0 0x0 0x0 0x0 0x4 0x0>;
 
 	misc@100000 {
 		compatible = "nvidia,tegra186-misc";
-- 
2.1.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2018-10-17  2:07 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-17  2:06 [PATCH 1/2] arm64: dts: tegra186: Add dma-ranges to avoid using bounce buffers Krishna Reddy
2018-10-17  2:06 ` [PATCH 2/2] arm64: dts: tegra186: Enable IOMMU for SDHCI Krishna Reddy

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®