How to get UART console access on Custom oWRT builds (for the spitz/x750)

Technical Support for Routers
1

Hi there.

Quick question.

When building an oWRT image from scratch using the gl-inet repo, it appears that the serial console is disabled. How do i fix this? I would like to be able to use the serial port to get into the device.

https://github.com/gl-inet/openwrt/blob/develop/target/linux/ar71xx/image/generic.mk#L530

Currently, the value is

CONSOLE := null,115200

and i want to know if

  CONSOLE := ttyATH0,115200

or

  CONSOLE := ttyS0,115200

will be the correct value

or is there anything else that i need to do (packages i need to (de)select with make menuconfig) in order to get the UART console login working?

Thanks!

2

You can using ttyS0

CONSOLE := ttyS0,115200
3

As I know, the UART is connected to the Bluetooth module. Your firmware will send all the output to the bluetooth module. If you don’t have the module that should be OK.

4

@luochongjun Thanks. I’ll give that a try. Do you know why it’s ttyATH0 for some units and ttyS0 for others?

@alzhao I am talking about the UART that’s exposed on the PCB as 4 unpopulated pins… next to the SIM slot and the USB port. I thought that the BT module was built in to the radio as i can see the “scan for BT devices” on the web interface… but i never do get any “results” back from a scan :/.

Is that correct? I have an unpopulated portion of the PCB next to the USB port that looks like some sort of module on board could be soldered there… i thought that the area was for the optional zigbee or zwave module.

Is blue tooth optional on this unit, too? Or, is there a way that i can tell what radios the unit has by looking at the model number or serial number or similar?

5

AR933x is ttyATH0, specific driver implementation

6

Can you give a photo of the PCB? Pls also tell me where you bought this.

7

Hi Aunixsystem,
Would you please provide your purchase channel and order number/id ?
Thanks!

8

compressed
compressed3299Ă—2301 801 KB

@alzhao Here’s the PCB w/ the unpopulated area. I don’t know where it was ordered from… i believe from the gl-inet website, but i would need to confirm with the person that bought it.

9

It does not have BLE module. Pls check where you bought this.

10

@alzhao

this was purchased from the gl-inet web shop about 6 weeks ago

11

If you buy from GL web shop. It is supposed to have BLE. If not, pls just contact cs@gl-inet.com

12

If anybody else comes across this thread in the future:

It is possible to order the unit w/o a BTLE radio. I saw the section in the UI where you could scan for BTLE devices and assumed that the radio was built into the SoC and figured that the unpopulated section on the board was for zigbee/zwave/lora… etc.

But that assumption was false. The SoC only has wifi radios. This explains why the stock firmware does not support a console via UART.

13

Bumping an “old” thread, because of the same problem and I think that there’s no need to open a new thread because it’s the same problem and the same device.

I have a gl-x750v2c6 with no BT/Zigbee devices and ttyS0 is disabled with stock and custom built kernel:

[    0.350382] console [ttyS0] disabled
[    0.354194] 18020000.uart: ttyS0 at MMIO 0x18020000 (irq = 9, base_baud = 1562500) is a 16550A

As this image is based on ATH79, checking target/linux/ath79/image/nand.mk

define Device/glinet_gl-x750-nor
    ATH_SOC := qca9531
    DEVICE_TITLE := GL.iNet GL-X750 (NOR)
    DEVICE_PACKAGES := kmod-usb2 kmod-ath10k ath10k-firmware-qca9887 block-mount 
    IMAGE_SIZE := 16000k
    SUPPORTED_DEVICES += gl-x750 glinet,gl-x750
endef
TARGET_DEVICES += glinet_gl-x750-nor

Does not seem to have serial ttyS0 disabled.

Is ttyS0 being used for mpcie modem? I do not think so, because quectel uses /dev/ttyUSBX for serial access.
Should ttyS0 be used for BT/ZigBee? It should not, because this device has no BT/ZigBee adapter soldered on board.

How can I enable ttyS0 in order to debug my kernel?

Very many Thanks.

14

ttyS0 is used for BT/Zigbee. Even there is no hardware connected, ttyS0 is not enabled because it is fixed.

You need to recompile firmware after you edit dtsi

image
image836Ă—279 5.02 KB

15

That’s a life saver comment.

I’d never imagine that setting bootargs to an empty string will override u-boot bootargs.

Very very many thanks!

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