Messages in this thread | | | Date | Mon, 26 Jun 2023 10:38:30 +0200 | Subject | Re: [PATCH 2/2] arch: arm64: configs: Enable UBI and UBIFS | From | Krzysztof Kozlowski <> |
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On 26/06/2023 06:16, Lee, Kah Jing wrote: >> -----Original Message----- >> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >> Sent: Saturday, 24 June, 2023 3:30 PM >> To: Lee, Kah Jing <kah.jing.lee@intel.com>; Dinh Nguyen >> <dinguyen@kernel.org>; Rob Herring <robh+dt@kernel.org>; Krzysztof >> Kozlowski <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley >> <conor+dt@kernel.org>; Catalin Marinas <catalin.marinas@arm.com>; Will >> Deacon <will@kernel.org> >> Cc: linux-kernel@vger.kernel.org >> Subject: Re: [PATCH 2/2] arch: arm64: configs: Enable UBI and UBIFS >> >> On 24/06/2023 05:42, Lee, Kah Jing wrote: >>>>>> So you miss init ramdisk. >>>>> Currently we are using the bootargs to mount the rootfs from QSPI >>>>> NOR >>>> flash: >>>>> [ 0.000000] Kernel command line: earlycon panic=-1 ubi.mtd=1 >>>> root=ubi0:rootfs rootfstype=ubifs rw rootwait >>>>> Is it possible to mount the ubifs rootfs with the ubifs=m config during >> boot? >>>> >>>> I think yes. rootfs devices are for example modules, so filesystem >>>> can be as well. >>> Was going through mtd ubifs page - >>> http://www.linux-mtd.infradead.org/faq/ubifs.html >>> Quoted: 'In order to mount UBIFS as the root file system, you have to >>> compile UBIFS into the kernel (instead of compiling it as a kernel >>> module) and specify proper kernel boot arguments and make the kernel >> mount UBIFS on boot.' >> >> Why? Module loaded by initramfs would also understand cmdline arguments, >> right? > The suggestion is to use initramfs for rootfs -> remount UBIFS as chroot? > The concern is additional initrd image and steps to store in the > limited NOR flash (256MB, Boot data + Uboot - ~66MB, UBIFS image - ~88MB, > kernel.itb - ~10MB = 164MB). > With the mounting Rootfs from UBIFS volume, we can skip the initrd step, and > save some space for the user operations. > Let me know if I understands that correctly.
arm64 defconfig creates huge development config for all platforms, so why would you ever use it in resource-constrained system? It would barely fit. defconfig modules take 50 MB alone and you don't need most of them.
I think you misunderstood the purpose of this defconfig and now try to apply some arguments for different use cases.
Best regards, Krzysztof
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