QEMU serial communication between guest and host

[Francisco]

I'm running an Linux Image (kernel 3.2.8) for beagleboard-xm on QEMU's 1.4.0
emulator.

qemu call cmd:

sudo qemu-system-arm -M beaglexm -m 1024 -sd ./test.img -clock unix -serial
stdio -device usb-mouse -device usb-kbd -chardev tty,id=tty,path=ttyS0
What I want to do is to have a communication between guest and host across
serial the 4 differents ttyO present on the guest. QEMU offer facilities to
redirect the trafic to some device in the host side. My problem goes like
this:

At the guest kernel boot Im able to see that my UART where enabled

[ 2.682040] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 2.777947] omap_uart.0: ttyO0 at MMIO 0x4806a000 (irq = 72) is a OMAP
UART0
[ 2.794967] omap_uart.1: ttyO1 at MMIO 0x4806c000 (irq = 73) is a OMAP
UART1
[ 2.814942] omap_uart.2: ttyO2 at MMIO 0x49020000 (irq = 74) is a OMAP
UART2
[ 2.966825] console [ttyO2] enabled
[ 2.984777] omap_uart.3: ttyO3 at MMIO 0x49042000 (irq = 80) is a OMAP
UART3
In fact when I go see in to /proc/tty/driver and I do a cat on OMAP-SERIAL
Im able to see this serinfo:1.0 driver revision:

0: uart:OMAP UART0 mmio:0x4806A000 irq:72 tx:0 rx:0 CTS|DSR|CD
1: uart:OMAP UART1 mmio:0x4806C000 irq:73 tx:0 rx:0 CTS|DSR|CD
2: uart:OMAP UART2 mmio:0x49020000 irq:74 tx:268 rx:37 RTS|CTS|DTR|DSR|CD
3: uart:OMAP UART3 mmio:0x49042000 irq:80 tx:0 rx:0 CTS|DSR|CD
I know that ttyO2 is working because my console is been redirected to it.
The thing is that doing a set serial on any of the ttyO I get the following
message:

[root@enu driver]# setserial -a /dev/ttyO0
/dev/ttyO0, Line 0, UART: undefined, Port: 0x0000, IRQ: 72
Baud_base: 3000000, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal
The same goes with ttyO2. I tried to set some settings to any of the ttyO
with setserial but I always get the same message:

[root@enu ~]# setserial /dev/ttyO0 uart 8250
setserial: can't set serial info: Invalid argument
[root@enu ~]# setserial /dev/ttyO0 port 0x4806a000
setserial: can't set serial info: Invalid argument
While looking at guest /proc/tty/drives this is what we see

/dev/tty /dev/tty 5 0 system:/dev/tty
/dev/console /dev/console 5 1 system:console
/dev/ptmx /dev/ptmx 5 2 system
/dev/vc/0 /dev/vc/0 4 0 system:vtmaster
sdio_uart /dev/ttySDIO 249 0-7 serial
acm /dev/ttyACM 166 0-31 serial
ttyprintk /dev/ttyprintk 5 3 console
OMAP-SERIAL /dev/ttyO 253 0-3 serial
serial /dev/ttyS 4 64-95 serial
pty_slave /dev/pts 136 0-1048575 pty:slave
pty_master /dev/ptm 128 0-1048575 pty:master
unknown /dev/tty 4 1-63 console
Basically I want to establish a serial communication between a guest and a
host, but the serial ports on the guest side aren't well configured.

PS: I also tryied with -serial arg on qemu's cmd call and nothing.

Can someone help me?

[Kees Jongenburger]

Hi

On Mon, Jun 10, 2013 at 1:45 AM, Francisco <franc...@hotmail.com> wrote:
> I'm running an Linux Image (kernel 3.2.8) for beagleboard-xm on QEMU's 1.4.0
> emulator.
>
> qemu call cmd:
>
> sudo qemu-system-arm -M beaglexm -m 1024 -sd ./test.img -clock unix -serial
> stdio -device usb-mouse -device usb-kbd -chardev tty,id=tty,path=ttyS0
> What I want to do is to have a communication between guest and host across
> serial the 4 differents ttyO present on the guest. QEMU offer facilities to
> redirect the trafic to some device in the host side. My problem goes like
> this:

I use -serial pty ( on linaro's qemu 1.2) perhaps you can look into
this option. this would also remove the need to run a root.

Greetings