6.15-stable review patch. If anyone has any objections, please let me know.
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From: Chen-Yu Tsai wenst@chromium.org
[ Upstream commit 267623000d11f6d483214be2484555f600393a12 ]
Based on the comments in the MT8188 IOMMU binding header, the rdma0 device specifies the wrong IOMMU device for the IOMMU port it is tied to:
This SoC have two MM IOMMU HWs, this is the connected information: iommu-vdo: larb0/2/5/9/10/11A/11C/13/16B/17B/19/21 iommu-vpp: larb1/3/4/6/7/11B/12/14/15/16A/17A/23/27
rdma0's endpoint is M4U_PORT_L1_DISP_RDMA0 (on larb1), which should use iommu-vpp, but it is currently tied to iommu-vdo.
Somehow this went undetected until recently in Linux v6.15-rc1 with some IOMMU subsystem framework changes that caused the IOMMU to no longer work. The IOMMU would fail to probe if any devices associated with it could not be successfully attached. Prior to these changes, only the end device would be left without an IOMMU attached.
Fixes: 7075b21d1a8e ("arm64: dts: mediatek: mt8188: Add display nodes for vdosys0") Signed-off-by: Chen-Yu Tsai wenst@chromium.org Reviewed-by: Jason-JH Lin jason-jh.lin@mediatek.com Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Link: https://lore.kernel.org/r/20250408092303.3563231-1-wenst@chromium.org Signed-off-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/boot/dts/mediatek/mt8188.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/mediatek/mt8188.dtsi b/arch/arm64/boot/dts/mediatek/mt8188.dtsi index 69a8423d38589..29d35ca945973 100644 --- a/arch/arm64/boot/dts/mediatek/mt8188.dtsi +++ b/arch/arm64/boot/dts/mediatek/mt8188.dtsi @@ -2579,7 +2579,7 @@ reg = <0 0x1c002000 0 0x1000>; clocks = <&vdosys0 CLK_VDO0_DISP_RDMA0>; interrupts = <GIC_SPI 638 IRQ_TYPE_LEVEL_HIGH 0>; - iommus = <&vdo_iommu M4U_PORT_L1_DISP_RDMA0>; + iommus = <&vpp_iommu M4U_PORT_L1_DISP_RDMA0>; power-domains = <&spm MT8188_POWER_DOMAIN_VDOSYS0>; mediatek,gce-client-reg = <&gce0 SUBSYS_1c00XXXX 0x2000 0x1000>;