[PATCH v11 7/7] arm64: dts: ti: iot2050: Add overlay for DMA isolation for devices behind PCI RC
From: <hidden>
Date: 2025-07-23 03:46:27
Also in:
linux-devicetree, linux-pci, lkml
Subsystem:
arm/texas instruments k3 architecture, the rest · Maintainers:
Nishanth Menon, Vignesh Raghavendra, Tero Kristo, Linus Torvalds
From: Jan Kiszka <jan.kiszka@siemens.com> Reserve a 64M memory region and ensure that all PCI devices do their DMA only inside that region. This is configured via a restricted-dma-pool and enforced with the help of the first PVU. Applying this isolation is not totally free in terms of overhead and memory consumption. It makes only sense for variants that support secure booting, and generally only when this is actually enable. Therefore model it as overlay that can be activated on demand. The firmware will take care of this via DT fixup during boot and will also provide a way to adjust the pool size. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Li Hua Qian <redacted> --- arch/arm64/boot/dts/ti/Makefile | 5 +++ ...am6548-iot2050-advanced-dma-isolation.dtso | 33 +++++++++++++++++++ 2 files changed, 38 insertions(+) create mode 100644 arch/arm64/boot/dts/ti/k3-am6548-iot2050-advanced-dma-isolation.dtso
diff --git a/arch/arm64/boot/dts/ti/Makefile b/arch/arm64/boot/dts/ti/Makefile
index c6171de9fe88..66b1d8093fa2 100644
--- a/arch/arm64/boot/dts/ti/Makefile
+++ b/arch/arm64/boot/dts/ti/Makefile@@ -84,8 +84,10 @@ k3-am654-gp-evm-dtbs := k3-am654-base-board.dtb \ k3-am654-evm-dtbs := k3-am654-base-board.dtb k3-am654-icssg2.dtbo k3-am654-idk-dtbs := k3-am654-evm.dtb k3-am654-idk.dtbo k3-am654-pcie-usb2.dtbo k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-dtbs := k3-am6548-iot2050-advanced-m2.dtb \ + k3-am6548-iot2050-advanced-dma-isolation.dtbo \ k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie.dtbo k3-am6548-iot2050-advanced-m2-bkey-usb3-dtbs := k3-am6548-iot2050-advanced-m2.dtb \ + k3-am6548-iot2050-advanced-dma-isolation.dtbo \ k3-am6548-iot2050-advanced-m2-bkey-usb3.dtbo dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic.dtb dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic-pg2.dtb
@@ -288,7 +290,10 @@ DTC_FLAGS_k3-am62p5-sk += -@ DTC_FLAGS_k3-am642-evm += -@ DTC_FLAGS_k3-am642-phyboard-electra-rdk += -@ DTC_FLAGS_k3-am642-tqma64xxl-mbax4xxl += -@ +DTC_FLAGS_k3-am6548-iot2050-advanced += -@ DTC_FLAGS_k3-am6548-iot2050-advanced-m2 += -@ +DTC_FLAGS_k3-am6548-iot2050-advanced-pg2 += -@ +DTC_FLAGS_k3-am6548-iot2050-advanced-sm += -@ DTC_FLAGS_k3-am68-sk-base-board += -@ DTC_FLAGS_k3-am69-sk += -@ DTC_FLAGS_k3-j7200-common-proc-board += -@
diff --git a/arch/arm64/boot/dts/ti/k3-am6548-iot2050-advanced-dma-isolation.dtso b/arch/arm64/boot/dts/ti/k3-am6548-iot2050-advanced-dma-isolation.dtso
new file mode 100644
index 000000000000..dfd75d2dc245
--- /dev/null
+++ b/arch/arm64/boot/dts/ti/k3-am6548-iot2050-advanced-dma-isolation.dtso@@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IOT2050, overlay for isolating DMA requests via PVU + * Copyright (c) Siemens AG, 2024 + * + * Authors: + * Jan Kiszka <jan.kiszka@siemens.com> + */ + +/dts-v1/; +/plugin/; + +&{/reserved-memory} { + #address-cells = <2>; + #size-cells = <2>; + + pci_restricted_dma_region: restricted-dma@c0000000 { + compatible = "restricted-dma-pool"; + reg = <0 0xc0000000 0 0x4000000>; + }; +}; + +&pcie0_rc { + memory-region = <&pci_restricted_dma_region>; +}; + +&pcie1_rc { + memory-region = <&pci_restricted_dma_region>; +}; + +&ti_pvu0 { + status = "okay"; +};
--
2.34.1