Messages in this thread | | | From | Arnd Bergmann <> | Date | Fri, 24 Jan 2020 17:44:30 +0100 | Subject | Re: [PATCH] soc: imx: Makefile: only build soc-imx8 when CONFIG_ARM64 |
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On Fri, Jan 24, 2020 at 4:54 PM Adam Ford <aford173@gmail.com> wrote: > On Wed, Jan 15, 2020 at 4:39 AM Arnd Bergmann <arnd@arndb.de> wrote: > > On Wed, Jan 15, 2020 at 3:38 AM Peng Fan <peng.fan@nxp.com> wrote: > > I would be interested in learning more about running the i.MX8M in > 32-bit mode. I'm looking at running Linux on a device with < 1GB of > RAM, so having 32-bit pointers and instructions would be preferred. > My preference would be to run as ARMv7 for migration purposes, but I'm > open to alternatives. > > Does anyone have any suggestions on where I might find some generic > stuff for either iMX8M or generic ARMv8 docs for doing something like > this?
By far the easiest way is to just run a 64-bit kernel and 32-bit user space, which should give you 90% of the space savings. This requires no further work, just pick the 32-bit distro of your choice.
The get the last few percent of memory savings and run a 64-bit kernel, at least a bit of porting effort should be needed. In principle you should be able to pass the dtb file for your machine to a 32-bit kernel, but all drivers have to be there and you need to adjust a few dependencies to allow 32-bit builds such as
config CLK_IMX8MM bool "IMX8MM CCM Clock Driver" - depends on ARCH_MXC && ARM64 + depends on ARCH_MXC && ARM64 help Build the driver for i.MX8MM CCM Clock Driver
and then there will likely be a few bugs.
Arnd
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