[iotg][ehl][ehl-aaeon] TTY port ttyS5 has been occupied

[AaACM]

SKU: AAEON UPN-EHL01

Image used: Image used: ubuntu-20.04-preinstalled-desktop-amd64+intel-iot.img

Steps to reproduced
===================================================
1. Enable the CN62 RS232/422 on UPN-EHL01 in BIOS menu
"Advanced -> HSUART Configuration -> HSUART Controller" select "SIO",

2. Save BIOS configuration and reboot the device

3. booting into Ubuntu

Expected results
======================
the TTY device node /dev/ttyS5 was existed and can access the UART (RS232/422)

Actual results
=======================
The device node "/dev/ttyS5" is disappear and the error kernel log is "[ 3.200508] serial serial0: tty port ttyS5 registered" in the attachment.

[Kent Lin (kent-jclin)]

@Aaeon,

There is no UART port on AAEON's EHL board we received. Could you please provide it?

[Pierre Equoy (pieq)]

Image used: 20211202.2
SKU: AAEON UPN-EHL01
CID: 202109-29496

I connected the UART adapter (COM port) to the CN62 connector (see user manual[1]), then followed the steps from the description, and get the same error:

[ 2.670839] dw-apb-uart.7: ttyS4 at MMIO 0x600111e000 (irq = 33, base_baud = 114825) is a 16550A
[ 2.698850] dw-apb-uart.8: ttyS5 at MMIO 0x600111c000 (irq = 16, base_baud = 114825) is a 16550A
[ 2.711395] serial serial0: tty port ttyS5 registered
(...)
[ 2.731002] dw-apb-uart.9: ttyS6 at MMIO 0x600111b000 (irq = 17, base_baud = 114825) is a 16550A

and ttyS5 is absent:

$ ls /dev/ttyS*
/dev/ttyS0 /dev/ttyS10 /dev/ttyS12 /dev/ttyS14 /dev/ttyS16 /dev/ttyS18 /dev/ttyS2 /dev/ttyS21 /dev/ttyS23 /dev/ttyS25 /dev/ttyS27 /dev/ttyS29 /dev/ttyS30 /dev/ttyS4 /dev/ttyS7 /dev/ttyS9
/dev/ttyS1 /dev/ttyS11 /dev/ttyS13 /dev/ttyS15 /dev/ttyS17 /dev/ttyS19 /dev/ttyS20 /dev/ttyS22 /dev/ttyS24 /dev/ttyS26 /dev/ttyS28 /dev/ttyS3 /dev/ttyS31 /dev/ttyS6 /dev/ttyS8

[1] https://downloads.up-community.org/download/up-squared-6000-user-manual/

[Kent Lin (kent-jclin)]

From AAEON latest update, it seems like a BIOS issue.

But question to Ethan and Kernel team, Could Ubuntu check the ACPI table for COM port declared by BIOS?

=================================================

Subject: RE: R1.4 (EAPLAM14)(12/21/2018): EMB-APL1 BIOS Release

Dear Max,

昨天我有發一版M15 BIOS，有測試過Ubuntu & Windows下COM 1~6皆可以使用了。

Ubuntu似乎不像Windows一樣會參考BIOS宣告COM port的ACPI table，所以需要透過setserial這tool告訴OS COM port resource，SOP如下：

l sudo apt-get update

l sudo apt-get install setserial

l sudoedit /var/lib/setserial/autoserial.conf (如圖1)

1. 加入 (如圖1-1)

/dev/ttyS4 uart 16550A port 0x2F0 irq 11 baud_base 115200 spd_normal skip_test

/dev/ttyS5 uart 16550A port 0x2E0 irq 11 baud_base 115200 spd_normal skip_test

2. 按Ctrl+X離開，選manual (如圖1-2)

l sudo dpkg-reconfigure setserial

l reboot system

l sudo setserial –g /dev/ttyS[012345] (檢查COM port數值，如圖2)

另外，BIOS無法指定COM port IRQ的問題，目前COM port 3 & 4及5 & 6是share IRQ的方式，所以數值會共用。

Thanks

[Doug Jacobs (djacobs98)]

I tried the above modification to the system and was unable to get a port assigned to the serial devices.

I have attached the dmesg and acpidump logs taken before and after the modifications.

[Ivan Hu (ivan.hu)]

Checking the the kernel log,
The UART is with MMIO, not I/O port,
[ 3.122152] 0000:00:11.0: ttyS4 at MMIO 0x6001324000 (irq = 140, base_baud = 12500000) is a 16550A
...
[ 3.172039] 0000:00:11.1: ttyS5 at MMIO 0x6001322000 (irq = 141, base_baud = 12500000) is a 16550A

This should be the reason that setserial(only show I/O port and IRQ) doesn't show port information.

I also check the acpidump, I haven't seen the I/O port defined,
the UART resoure defined from the SystemMemory(BAR0)

Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings
{
    Return (UARH (UC00, UI00))
}

Method (UARH, 2, Serialized)
{
    OperationRegion (UACF, SystemMemory, Arg0, 0x18)
    Field (UACF, AnyAcc, NoLock, Preserve)
    {
        Offset (0x10),
        BAR0, 64
    }
...
}

[Anthony Wong (anthonywong)]

Per Ivan's comment in #9, this does not look like an issue. If so I think we should close this bug.