On Tue, Jul 28, 2020 at 10:26 AM Scott Whitney <s...@inea.com> wrote:
> Hi Bruce,
>
>
>
> I believe the recipe for building Variscite’s kernel is in
> meta-variscite-imx/recipes-kernel/linux/linux-variscite_4.19.35.bb, which
> does produce a booting U-Boot and Linux image. What would need to be
> modified to enable the rt-linux kernel? The recipe is provided below.
>
At a high level, you need to get the appropriate preempt-rt patch from the
-rt project, add it to the SRC_URI (via bbappend), fix the patch so that it
applies to that kernel, build, and then debug and boot failures.
That's the trivialized version of the steps.
As for how to get the patch and apply it, it is just like any other package
for patching, so you can lookup the details in the reference manuals and/or
find other kernel recipe examples that are doing something similar. They
will do a better job than I ever would explaining the steps here.
Cheers,
Bruce
>
>
> # Copyright (C) 2013-2016 Freescale Semiconductor
>
> # Copyright 2017 NXP
>
> # Copyright 2018-2019 Variscite Ltd.
>
> # Released under the MIT license (see COPYING.MIT for the terms)
>
>
>
> SUMMARY = "Linux kernel provided and supported by Variscite"
>
> DESCRIPTION = "Linux kernel provided and supported by Variscite (based on
> the kernel provided by NXP) \
>
> with focus on i.MX Family SOMs. It includes support for many IPs such as
> GPU, VPU and IPU."
>
>
>
> require recipes-kernel/linux/linux-imx.inc
>
> LICENSE = "GPLv2"
>
> LIC_FILES_CHKSUM = "file://COPYING;md5=bbea815ee2795b2f4230826c0c6b8814"
>
>
>
> DEPENDS += "lzop-native bc-native"
>
>
>
> DEFAULT_PREFERENCE = "1"
>
>
>
> SRCBRANCH = "imx_4.19.35_1.1.0_var01"
>
>
>
> LOCALVERSION_imx8mq-var-dart = "-imx8mq"
>
> LOCALVERSION_imx8mm-var-dart = "-imx8mm"
>
> LOCALVERSION_imx8mn-var-som = "-imx8mn"
>
> LOCALVERSION_imx8qxp-var-som = "-imx8x"
>
> LOCALVERSION_imx8qm-var-som = "-imx8qm"
>
>
>
> KERNEL_DEFCONFIG = "${S}/arch/arm64/configs/imx8_var_defconfig"
>
> DEFAULT_DTB_imx8mq-var-dart = "sd-lvds"
>
> DEFAULT_DTB_imx8qxp-var-som = "sd"
>
> DEFAULT_DTB_imx8qm-var-som = "lvds"
>
> DEFAULT_DTB_PREFIX_imx8mq-var-dart = "fsl-imx8mq-var-dart"
>
> DEFAULT_DTB_PREFIX_imx8qxp-var-som = "fsl-imx8qxp-var-som"
>
> DEFAULT_DTB_PREFIX_imx8qm-var-som = "fsl-imx8qm-var-som"
>
>
>
> KERNEL_SRC ?= "git://github.com/varigit/linux-imx;protocol=git"
>
> SRC_URI = "${KERNEL_SRC};branch=${SRCBRANCH}"
>
> SRCREV = "e6d3e3fefe4e85b5ee45beb7609b3c02bfe23efb"
>
>
>
> S = "${WORKDIR}/git"
>
>
>
> addtask copy_defconfig after do_patch before do_preconfigure
>
> do_copy_defconfig () {
>
> cp ${KERNEL_DEFCONFIG} ${WORKDIR}/defconfig
>
> }
>
>
>
> pkg_postinst_kernel-devicetree_append () {
>
> rm -f $D/boot/devicetree-*
>
> }
>
>
>
> pkg_postinst_kernel-devicetree_append_imx8mq-var-dart () {
>
> cd $D/boot
>
> ln -s ${DEFAULT_DTB_PREFIX}-${DEFAULT_DTB}.dtb
> ${DEFAULT_DTB_PREFIX}.dtb
>
> ln -s ${DEFAULT_DTB_PREFIX}-${DEFAULT_DTB}-cb12.dtb
> ${DEFAULT_DTB_PREFIX}-cb12.dtb
>
> }
>
>
>
> pkg_postinst_kernel-devicetree_append_imx8qxp-var-som () {
>
> cd $D/boot
>
> ln -s ${DEFAULT_DTB_PREFIX}-${DEFAULT_DTB}.dtb
> ${DEFAULT_DTB_PREFIX}.dtb
>
> }
>
>
>
> pkg_postinst_kernel-devicetree_append_imx8qm-var-som () {
>
> cd $D/boot
>
> ln -s ${DEFAULT_DTB_PREFIX}-${DEFAULT_DTB}.dtb
> ${DEFAULT_DTB_PREFIX}.dtb
>
> ln -s fsl-imx8qm-var-spear-${DEFAULT_DTB}.dtb fsl-imx8qm-var-spear.dtb
>
> }
>
>
>
> COMPATIBLE_MACHINE = "(mx8)"
>
> EXTRA_OEMAKE_append_mx8 = " ARCH=arm64"
>
>
>
> *Scott D. Whitney*
>
> *s...@inea.com <s...@inea.com>* | T: 781-801-1152 |
> F: 781-801-1108 | *www.inea.com <http://www.inea.com/>*
>
>
>
> *From:* Bruce Ashfield <bruce.ashfi...@gmail.com>
> *Sent:* Tuesday, July 28, 2020 10:18 AM
> *To:* Scott Whitney <s...@inea.com>
> *Cc:* yo...@yoctoproject.org
> *Subject:* Re: [yocto] How to enable preempt-rt in Yocto Zeus or Warrior?
>
>
>
>
>
>
>
> On Tue, Jul 28, 2020 at 8:45 AM Scott Whitney <s...@inea.com> wrote:
>
> Hi Bruce,
>
>
>
> Yes, we are using Linux built by Yocto, but where is the preferred
> provider for the kernel set to linux-yocto-rt?
>
>
>
>
>
> This is one of the nuances about OE/Yocto, it isn't about building the
> kernel with yocto, I was wondering about the kernel recipe you are using.
>
>
>
> If you have a booting kernel built from linux-yocto (the recipe), then the
> switch to -rt is easy. If it isn't using linux-yocto, then using -rt is
> specific to the kernel provider that you have (and it may be just as easy
> as the linux-yocto switch ... just without the details of that
> recipe/provider, I can't say).
>
>
>
> The preferred provider is likely set in the vendor's BSP layer, and it
> likely points at whatever vendor kernel they are currently shipping.
>
>
>
> Cheers,
>
>
>
> Bruce
>
>
>
>
>
> Thanks for your help
>
>
>
> *Scott D. Whitney*
>
> *s...@inea.com <s...@inea.com>* | T: 781-801-1152 |
> F: 781-801-1108 | *www.inea.com <http://www.inea.com/>*
>
>
>
> *From:* Bruce Ashfield <bruce.ashfi...@gmail.com>
> *Sent:* Monday, July 27, 2020 10:04 PM
> *To:* Scott Whitney <s...@inea.com>
> *Cc:* yo...@yoctoproject.org
> *Subject:* Re: [yocto] How to enable preempt-rt in Yocto Zeus or Warrior?
>
>
>
>
>
>
>
> On Mon, Jul 27, 2020 at 3:51 PM Scott Whitney <s...@inea.com> wrote:
>
> Hi Yocto group,
>
>
>
> I’m working with a newly-released copy of Yocto Zeus from Variscite for
> the i.MX8MM Mini, although the same option seems to apply to the previous
> Yocto Warrior.
>
>
>
> I understand that a Linux real-time kernel can be enabled by setting
> LINUX_KERNEL_TYPE = “preempt-rt”. Where does this option need to be set so
> that when I bitbake fsl-image-qt5, I get the Linux “preempt-rt” kernel
> instead of the “standard” kernel?
>
>
>
> Is there a specific configuration file that needs to be modified, or a new
> recipe in a layer? I am confused and hoping that you can help.
>
>
>
> If you aren't using linux-yocto, you'll need to arrange for the preempt-rt
> patch(es) to be applied to whatever kernel you are using. Which means you
> are creating a new recipe, bbappending an existing one, or if you are lucky
> the kernel provider already has a -rt recipe available.
>
>
>
> If you are using linux-yocto, it's as simple as setting the preferred
> provider of the kernel as linux-yocto-rt and building.
>
>
>
> Bruce
>
>
>
>
>
>
>
> Best regards,
>
>
>
> *Scott D. Whitney*
>
> Principal Software Engineer
>
>
> Intertech Engineering Associates, Inc.
> 100 Lowder Brook Drive, Suite 2500
> Westwood, MA 02090
> *s...@inea.com <s...@inea.com>* | T: 781-801-1152 |
> F: 781-801-1108 | *www.inea.com <http://www.inea.com/>*
>
>
>
>
>
>
>
>
> --
>
> - Thou shalt not follow the NULL pointer, for chaos and madness await thee
> at its end
> - "Use the force Harry" - Gandalf, Star Trek II
>
>
>
>
> --
>
> - Thou shalt not follow the NULL pointer, for chaos and madness await thee
> at its end
> - "Use the force Harry" - Gandalf, Star Trek II
>
--
- Thou shalt not follow the NULL pointer, for chaos and madness await thee
at its end
- "Use the force Harry" - Gandalf, Star Trek II
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