On Fri, Dec 05, 2025 at 05:00:20PM -0600, Bjorn Andersson wrote: > On Fri, Nov 21, 2025 at 04:31:16PM +0530, Mukesh Ojha wrote: > > All the Lemans IOT variants boards are using Gunyah hypervisor which > > means that, so far, Linux-based OS could only boot in EL1 on those > > devices. However, it is possible for us to boot Linux at EL2 on these > > devices [1]. > > > > When running under Gunyah, remote processor firmware IOMMU streams is > > controlled by the Gunyah however when Linux take ownership of it in EL2, > > It need to configure it properly to use remote processor. > > > > Add a EL2-specific DT overlay and apply it to Lemans IOT variant > > devices to create -el2.dtb for each of them alongside "normal" dtb. > > > > [1] > > https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-4/boot-developer-touchpoints.html#uefi > > > > Signed-off-by: Mukesh Ojha <[email protected]> > > --- > > arch/arm64/boot/dts/qcom/Makefile | 10 ++++++++ > > arch/arm64/boot/dts/qcom/lemans-el2.dtso | 41 > > ++++++++++++++++++++++++++++++++ > > 2 files changed, 51 insertions(+) > > > > diff --git a/arch/arm64/boot/dts/qcom/Makefile > > b/arch/arm64/boot/dts/qcom/Makefile > > index 6f34d5ed331c..56efd90b7a5e 100644 > > --- a/arch/arm64/boot/dts/qcom/Makefile > > +++ b/arch/arm64/boot/dts/qcom/Makefile > > @@ -37,6 +37,10 @@ lemans-evk-camera-dtbs := lemans-evk.dtb > > lemans-evk-camera.dtbo > > > > dtb-$(CONFIG_ARCH_QCOM) += lemans-evk-camera-csi1-imx577.dtb > > dtb-$(CONFIG_ARCH_QCOM) += lemans-evk-camera.dtb > > + > > +lemans-evk-el2-dtbs := lemans-evk.dtb lemans-el2.dtbo > > + > > +dtb-$(CONFIG_ARCH_QCOM) += lemans-evk-el2.dtb > > dtb-$(CONFIG_ARCH_QCOM) += monaco-evk.dtb > > dtb-$(CONFIG_ARCH_QCOM) += msm8216-samsung-fortuna3g.dtb > > dtb-$(CONFIG_ARCH_QCOM) += msm8916-acer-a1-724.dtb > > @@ -142,6 +146,12 @@ dtb-$(CONFIG_ARCH_QCOM) += qcs8300-ride.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qcs8550-aim300-aiot.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qcs9100-ride.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qcs9100-ride-r3.dtb > > + > > +qcs9100-ride-el2-dtbs := qcs9100-ride.dtb lemans-el2.dtbo > > +qcs9100-ride-r3-el2-dtbs := qcs9100-ride-r3.dtb lemans-el2.dtbo > > + > > +dtb-$(CONFIG_ARCH_QCOM) += qcs9100-ride-el2.dtb > > +dtb-$(CONFIG_ARCH_QCOM) += qcs9100-ride-r3-el2.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qdu1000-idp.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qrb2210-rb1.dtb > > dtb-$(CONFIG_ARCH_QCOM) += qrb4210-rb2.dtb > > diff --git a/arch/arm64/boot/dts/qcom/lemans-el2.dtso > > b/arch/arm64/boot/dts/qcom/lemans-el2.dtso > > new file mode 100644 > > index 000000000000..af35039946e3 > > --- /dev/null > > +++ b/arch/arm64/boot/dts/qcom/lemans-el2.dtso > > @@ -0,0 +1,41 @@ > > +// SPDX-License-Identifier: BSD-3-Clause > > +/* > > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. > > + */ > > + > > +/* > > + * Lemans specific modifications required to boot in EL2. > > + */ > > + > > +/dts-v1/; > > +/plugin/; > > + > > +&iris { > > + /* More driver work is needed */ > > You can write this comment without referring to some particular > implementation (as DeviceTree should). > > /* The binding doesn't allow for describing the firmware IOMMU stream yet */ > > > + status = "disabled"; > > +}; > > + > > +/* > > + * When running under Gunyah, remote processor firmware IOMMU streams is > > + * controlled by the Gunyah however when we take ownership of it in EL2, > > + * we need to configure it properly to use remote processor. > > The comment describes how things work with Gunyah, and then from that > angle explains why we need this. I'd find it preferable to keep the > perspective of not having Gunyah. Something as simple as: > > /* > * Without Gunyah, the IOMMU is managed by the consumer of this DeviceTree, > * so describe the firmware streams for each remoteproc. > */ > > That said, once the iris binding (and others) allow us to describe the > firmware stream, this comment will be misplaced. So perhaps apply my > feedback to the commit message and omit the comment here. If someone > wonders why it looks like it does, the commit message in the git history > will tell them.
Will move all the required comments into description of commit message. -- -Mukesh Ojha
