Disable serial console of u-boot on TX2

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hello, in our system we are using ttyS0 port for communicating with another device. This configuration prevents TX2 from booting up. We couldn’t get past u-boot phase.

So far, I have tried disabling serial console by modifying the u-boot source code as described in a stackoverflow post:

https://stackoverflow.com/questions/34356844/how-to-disable-serial-consolenon-kernel-in-u-boot?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

in u-boot/include/configs/p2771-0000.h I added the following lines:

#define CONFIG_DISABLE_CONSOLE
#define CONFIG_SILENT_CONSOLE
#define CONFIG_SYS_DEVICE_NULLDEV
#define CONFIG_SILENT_U_BOOT_ONLY

#define CONFIG_BOARD_EARLY_INIT_F 1
#define CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC

and in u-boot/arch/arm/mach-tegra/board186.c I added:
int board_early_init_f(void)
{
+gd->flags |= (GD_FLG_SILENT | GD_FLG_DISABLE_CONSOLE);
return 0;
}

Is there anything else that I need to change in order to disable the console?

2

Don’t know if this will do it, but in the U-Boot source, file “include/configs/p2371-2180.h” you might try removing this define:

#define CONFIG_TEGRA_ENABLE_UARTA
3

In the current version of sources (28.2), I don’t have CONFIG_TEGRA_ENABLE_UARTA definition in “include/configs/p2771-0000.h” .

The header file is as follows:

/*

  • Copyright (c) 2013-2016, NVIDIA CORPORATION.
  • SPDX-License-Identifier: GPL-2.0
    */

#ifndef _P2771_0000_H
#define _P2771_0000_H

#include <linux/sizes.h>

#include “tegra186-common.h”

/* High-level configuration options */
#define CONFIG_TEGRA_BOARD_STRING “NVIDIA P2771-0000”

/* I2C */
#define CONFIG_SYS_I2C_TEGRA

/* SD/MMC */
#define CONFIG_MMC
#define CONFIG_GENERIC_MMC
#define CONFIG_TEGRA_MMC

/* Environment in eMMC, at the end of 2nd “boot sector” */
#define CONFIG_ENV_IS_IN_MMC
#define CONFIG_SYS_MMC_ENV_DEV 0
#define CONFIG_SYS_MMC_ENV_PART 2
#define CONFIG_ENV_OFFSET (-CONFIG_ENV_SIZE)

/* PCI host support */
#define CONFIG_PCI
#define CONFIG_PCI_PNP
#define CONFIG_CMD_PCI

/* Silence UART at start-up – my modifications --*/
#define CONFIG_DISABLE_CONSOLE
#define CONFIG_SILENT_CONSOLE
#define CONFIG_SYS_DEVICE_NULLDEV
#define CONFIG_SILENT_U_BOOT_ONLY

#define CONFIG_BOARD_EARLY_INIT_F 1
#define CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC

#define BOARD_EXTRA_ENV_SETTINGS
"calculated_vars=kernel_addr_r fdt_addr_r scriptaddr pxefile_addr_r "
“ramdisk_addr_r\0”
“kernel_addr_r_align=00200000\0”
“kernel_addr_r_offset=00080000\0”
“kernel_addr_r_size=02000000\0”
“kernel_addr_r_aliases=loadaddr\0”
“fdt_addr_r_align=00200000\0”
“fdt_addr_r_offset=00000000\0”
“fdt_addr_r_size=00200000\0”
“scriptaddr_align=00200000\0”
“scriptaddr_offset=00000000\0”
“scriptaddr_size=00200000\0”
“pxefile_addr_r_align=00200000\0”
“pxefile_addr_r_offset=00000000\0”
“pxefile_addr_r_size=00200000\0”
“ramdisk_addr_r_align=00200000\0”
“ramdisk_addr_r_offset=00000000\0”
“ramdisk_addr_r_size=02000000\0”

#include “tegra-common-post.h”

/* Crystal is 38.4MHz. clk_m runs at half that rate */
#define COUNTER_FREQUENCY 19200000

#undef CONFIG_NR_DRAM_BANKS
#define CONFIG_NR_DRAM_BANKS (1024 + 2)

#endif

Edit: I’m sorry, I noticed that I already removed that define.

4

Hi,

Do you want to disable only the uboot log or also the whole bootloader message on uart?

If you want to totally disable uart, please refer to L4T document →
“Kernel Boot Time Optimization”. → “Disable Debugging”

5

I want to disable whole bootloader communication on uart.

6

You may be using the wrong source. Line 19 should be the define listed in my reply above.

The R28.2 version of U-Boot can be downloaded with the driver package’s source_sync.sh:

./source_sync.sh -u tegra-l4t-r28.2
7

@linuxdev I noticed that you are mentioning “p2371-2180.h”. I thought this file is related to TX1 and “p2771-0000.h” is related to TX2, and I worked on this file.

I tried removing that line in “p2371-2180.h” now, but it didn’t solve my problem.

@WayneWWW L4T docs says in Kernel Boot Time Optimization → Disable Debugging

Disable Debugging
To reduce boot time, disable debugging kernel hacks in the production configuration.
For example: FTRACE, TRACER, KMEMLEAK, etc.

I’m not sure how to use this. Am I referring to the right document?

8

Hi,

Sorry that I notice our document has some content that is out-of-date. Please refer to this thread and reflash your device to see if uart log is gone.

https://devtalk.nvidia.com/default/topic/1030489