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.
# 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
[cid:image003.png@01D664C9.78C615A0]
s...@inea.com<mailto: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<mailto: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
[cid:image002.png@01D664C9.78BEC2A0]
s...@inea.com<mailto: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<mailto:bruce.ashfi...@gmail.com>>
Sent: Monday, July 27, 2020 10:04 PM
To: Scott Whitney <s...@inea.com<mailto:s...@inea.com>>
Cc: yo...@yoctoproject.org<mailto: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<mailto: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
[cid:image002.png@01D664C9.78BEC2A0]
Intertech Engineering Associates, Inc.
100 Lowder Brook Drive, Suite 2500
Westwood, MA 02090
s...@inea.com<mailto: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
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