Rootfs loading issue

Hugo.K · November 25, 2020, 9:41am

Hello,

We buy an ultra96 v2 for an internal project.
The example BSP is working fine.
We try to rebuild a simple BSP with petalinux. The hardware design is made with Vivado, this is a simple design with only the zynq and block automation.

The petalinux build is OK, with the process below :

Create a new petalinux project with : petalinux-create -t project -n ultra96 --template zynqMP
Import hardware description with : petalinux-config --get-hw-description
Configure target board and serial : petalinux-config
→ Subsytem AUTO Hardware settings → Serial = psu_uart_1
→ DTG Settings → MACHINE_NAME = zcu100-revc
→ u-boot conf → target = xilinx_zynqmp_virt_defconfig
→ Yocto Settings → YOCTO_MACHINE_NAME = ultra96-zynqmp
→ Image Packaging → device node = /dev/mmcblk0p2
Build the project : petalinux-build
Package images : petalinux-package --boot --format BIN --fsbl images/linux/zynqmp_fsbl.elf --u-boot images/linux/u-boot.elf --pmufw images/linux/pmufw.elf --fpga images/linux/*.bit --force
Copy BOOT.BIN and image.ub in the first FAT partition of the sd card
Wirte rootfs.ext4 in the second partition :
→ dd if=images/linux/rootfs.ext4 of=/dev/mmcblk0p2
→ resize2fs /dev/mmcblk0p2
→ fsck /dev/mmcblk0p2

With these parameters, FSBL, u-boot and kernel loading are okay but during the kernel start, when rootfs is loaded the serial console is stuck.

I suspect an issue about the serial console, I think init reconfigure the UART or the system and the serial console is lost.

Someone have feedback about this type of issue?

Hugo.K · November 26, 2020, 4:49pm

I solved the issue.

In the example BSP a patch is applied on the kernel sources :

github.com

Avnet/ultra96-PYNQ/blob/master/ultra96/petalinux_bsp_v2/meta-user/recipes-kernel/linux/linux-xlnx/0001-Revert-tty-xilinx_uartps-Fix-missing-id-assignment-t.patch

From 6d965ab3773403618a66c6cd026e954b2513dba8 Mon Sep 17 00:00:00 2001
From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Tue, 30 Jun 2020 11:24:20 +0530
Subject: [PATCH] Revert "tty: xilinx_uartps: Fix missing id assignment to the
 console"

This reverts commit 2ae11c46d5fdc46cb396e35911c713d271056d35.

It turned out to break the ultra96-rev1, e.g., which uses uart1 as
serial0 (and stdout-path = "serial0:115200n8").

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Link: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-linus&id=76ed2e105796710cf5b8a4ba43c81eceed948b70
State: waiting (tty tree)
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
---
 drivers/tty/serial/xilinx_uartps.c | 1 -

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I add it into my petalinux project and the serial console is working fine.