[Buildroot] [PATCH v5] board: add support for ARM Juno r1 Development Board

Fri Oct 23 09:10:54 UTC 2015

Hi,

On 10/22/2015 9:20 PM, Arnout Vandecappelle wrote:
> On 22-10-15 18:17, Joao Pinto wrote:
>> The Juno r1 ARM Development Platform (ADP) is a software development
>> platform for ARMv8-A, it includes the Juno r1 Versatile Express board 
>> and an ARMv8-A reference software port available through Linaro.
>>
>> Signed-off-by: Joao Pinto <jpinto at synopsys.com>
>> ---
>>
>> Changes v4 -> v5:
>>  -Added changelog to the patch
>> Changes v3 -> v4  (Thomas Petazzoni):
>>  -The kernel' arm64 defconfig lacks a considerable amount of 
>>  configuration items regarding the Juno r1 board, and that is the reason
>>  of this custom kernel configuration file.
>>  -The ARM Juno needs a kernel image called Image, and that 
>>  it the reason why BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM is being used.
>>  -A new readme.txt was produced.
>>
>>  board/arm/junor1/linux-junor1-defconfig | 176 ++++++++++++++++++++++++++++++++
>>  board/arm/junor1/readme.txt             |  76 ++++++++++++++
>>  configs/arm_junor1_defconfig            |  16 +++
>>  3 files changed, 268 insertions(+)
>>  create mode 100644 board/arm/junor1/linux-junor1-defconfig
>>  create mode 100644 board/arm/junor1/readme.txt
>>  create mode 100644 configs/arm_junor1_defconfig
>>
>> diff --git a/board/arm/junor1/linux-junor1-defconfig b/board/arm/junor1/linux-junor1-defconfig
>> new file mode 100644
>> index 0000000..b216d3e
>> --- /dev/null
>> +++ b/board/arm/junor1/linux-junor1-defconfig
> 
>  This defconfig again contains a lot of options that I doubt are very useful. It
> even enables some things that are explicitly disabled in the arm64 defconfig, e.g.
> 
> # CONFIG_UTS_NS is not set
> # CONFIG_WIRELESS is not set
> 
> 
>  But it doesn't look too bad, so I'm OK with it as it is.
> 
> [snip]
> 
>> diff --git a/board/arm/junor1/readme.txt b/board/arm/junor1/readme.txt
>> new file mode 100644
>> index 0000000..2b3ebf5
>> --- /dev/null
>> +++ b/board/arm/junor1/readme.txt
>> @@ -0,0 +1,76 @@
>> +ARM Juno r1
>> +
>> +Intro
>> +=====
>> +
>> +These instructions apply to all models of the ARM Juno:
>> +  - Juno r0 (does not support PCIe)
>> +  - Juno r1 (supports PCIe)
> 
>  If the same binaries apply to both r0 and r1, why not call it something juno
> without r1?

I agree.

> 
>> +
>> +Buildroot will generate the kernel image, device tree blob and a 
>> +minimal root filesystem.
>> +
>> +How to build it
>> +===============
>> +
>> +Configure Buildroot
>> +-------------------
>> +
>> +Configuring Buildroot is pretty simple, just execute:
>> +
>> +  $ make arm_junor1_defconfig
>> +
>> +Build the rootfs, kernel and DTB
>> +--------------------------------
>> +
>> +Note: you will need to have access to the network, since Buildroot will
>> +download the packages' sources.
>> +
>> +You may now build your rootfs with:
>> +
>> +  $ make
>> +
>> +(This may take a while)
> 
>  I think this is a lot of text for something so simple :-)
> 
>> +
>> +Result of the build
>> +-------------------
>> +
>> +After building, you should obtain this tree:
>> +
>> +    output/images/
>> +    +-- rootfs.tar
>> +    +-- juno-r1.dtb
>> +    +-- Image
>> +
>> +Preparing your rootfs
>> +======================
>> +Format your pen drive as a ext3 filesystem by executing:
>> +
>> +   $ mkfs.ext3 /dev/<your device> 
>> +
>> +Installing your rootfs
>> +======================
>> +After mounting the pen drive please execute the following:
>> +
>> +   $ sudo tar -xvf output/images/rootfs.tar -C <pen drive mount path>
>> +
>> +When completed make sure to unmount the device:
>> +   
>> +   $ umount <pen drive mount path>
>> +
>> +Insert the pen drive in one of the ARM Juno' USB type A connectors.
> 
>  So why not just generate an ext4 image instead of this procedure?
> 
>> +
>> +Installing kernel image and DTB
>> +===============================
>> +1. Connect to the ARM Juno UART0 and execute USB_ON in the terminal
> 
>  What does this mean? I mean, if the system is running, you'd have a getty on
> UART0, no?
> 
>> +2. Connect a USB cable between your PC and ARM Juno USB type B connector
>> +   A mass storage device should appear in your desktop.
>> +3. Open the software/ folder
>> +4. Copy the 'Image' file to software/
>> +5. Copy the 'juno-r1.dtb' file to software/ and rename it to r1a57a53.dtb
>> +6. Press the red button in the front pannel of ARM Juno
> 
>  Is there no way to boot directly from the pen drive instead?

The procedure I describe here is the board' default and it is the one that we
use here at Synopsys. It is possible that other methods can be used.

> 
>> +
>> +At this time, the board will erase the Flash entry for each new item and
>> +replace it with the lastest ones.
>> +When finished, the board will boot and mount the root filesystem at /dev/sda1.
>> +
>> diff --git a/configs/arm_junor1_defconfig b/configs/arm_junor1_defconfig
>> new file mode 100644
>> index 0000000..3987293
>> --- /dev/null
>> +++ b/configs/arm_junor1_defconfig
>> @@ -0,0 +1,16 @@
>> +BR2_aarch64=y
>> +BR2_KERNEL_HEADERS_VERSION=y
>> +BR2_DEFAULT_KERNEL_VERSION="4.2.2"
>> +BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_2=y
>> +BR2_TARGET_GENERIC_HOSTNAME="junor1-buildroot"
>> +BR2_TARGET_GENERIC_ISSUE="Welcome to SNPS Juno r1 by Buildroot"
>> +BR2_LINUX_KERNEL=y
>> +BR2_LINUX_KERNEL_CUSTOM_GIT=y
>> +BR2_LINUX_KERNEL_CUSTOM_REPO_URL="http://git.linaro.org/landing-teams/working/arm/kernel.git"
>> +BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="6917b51dee54f21816706af2278517b7af218f9a"
> 
>  This is just v4.3-rc1, so you could use an upstream kernel instead of Linaro.
> Are you sure you took the right sha?

The Juno board was recently added to linux mainline (v4.2 I think) but the total
support is still in Linaro. Take as an example the video output support, sound
and pcie. The git commid id I configured is one of the latest, assuring that we
have the maximum of stable functionalities as possible. The stable tags lack
crucial features.

> 
>> +BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>> +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/arm/junor1/linux-junor1-defconfig"
>> +BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM=y
>> +BR2_LINUX_KERNEL_IMAGE_TARGET_NAME="Image"
>> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
>> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="arm/juno-r1"
> 
>  No need for a bootloader?

The board uses EDK2, which comes already built with the board.
If a developer needs to build a custom package it should get teh edk2 package a
built it.

> 
>  Regards,
>  Arnout
> 
> 
> 

Thanks,
Joao