On Fri, Mar 13, 2020 at 7:23 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Fri, Mar 13, 2020 at 4:38 AM <peng.fan@xxxxxxx> wrote: > > > > From: Peng Fan <peng.fan@xxxxxxx> > > > > To support aarch32 mode linux on aarch64 hardware, we need > > build the device tree, so include the arm64 device tree path. > > > > Signed-off-by: Peng Fan <peng.fan@xxxxxxx> > > --- > > There are a few other platforms with similar requirements, in > particular bcm2837, > so maybe try doing it the same way they do, see > arch/arm64/boot/dts/broadcom/bcm2837-rpi-3-b.dts I think this was discussed over again, but it is odd to tightly couple DT and Linux arch. Maybe, a long time solution might be to create a new directory, dts/ and collect all DT stuff into it. dts/<vendor>/<board>.dts Then, also move like follows: Documentation/devicetree/bindings/ -> dts/Bindings/ include/dt-bingins/ -> dts/include/dt-bindings/ > > > V1: > > This is just the device tree part. Besides this, > > I am not sure whether need to create a standalone defconfig under arm32 > > for aarch32 mode linux on aarch64 hardware, or use multi_v7_defconfig. > > multi_v7_defconfig should be ok, need to include LPAE config. > > I'd rather not have a standalone defconfig for it, given that we have a > single defconfig for all armv6/armv7/armv7hf i.mx machines. > > There was a suggestion to use a fragment for enabling an LPAE > multi_v7_defconfig recently, which I think is still under discussion but > should also help here, both with imx_v6_v7_defconfig and multi_v7_defconfig. > > Can you remind us why this platform needs LPAE? Is it only needed to > support more than 4GB of RAM, or something else on top of that? > Note that users that actually have 4GB or more on i.mx8 should > really run a 64-bit kernel anyway, even if they prefer using 32-bit user > space. > > Turning on LPAE not only disables imx3 and imx5 but also the Cortex-A9 > based imx6 variants. > > Arnd -- Best Regards Masahiro Yamada
