Re: GPIO-IN/OUT in Qemu

[Mahmoud Shirazi]

​Dear Peter,

I am working on Windows machine. Then, I connect the serial port, i.e. UART1, 
to a virtual COM port on the host. Sending the data from the guest to host 
works successfully; however, when I send the data from the host to the guest, 
the guest does not receive anything. I checked it and I find that the interrupt 
is not raises in the guest although it is enabled.  My it is due to a bug in 
Qemu? or something else that I am missing...?
Best,
Mahmoud
Mahmoud Shirazi, PhD
Assistant Professor, 
Department of Computer Science and Information Technology,
Institute for Advanced Studies in Basic Sciences (IASBS),
Zanjan, Iran
Tel: +98-24-33153395
http://iasbs.ac.ir/~m.shirazi


On Mon, 05/10/2021 01:24 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
> 
On Sun, 9 May 2021 at 17:15, Mahmoud Shirazi " 
target="_blank"><m.shirazi@iasbs.ac.ir> wrote:
> > I checked many machines (boards) in Qemu. Al all of them, all UARTs are as 
> > gpio-out. Does it means that the connection between the guest and host is 
> > in one direction (from guest to host)?
> > If yes, I there is a way to have a bidirectional connection between the 
> > guest and host over UART?
> 
> No, UARTs are all bidirectional. You can connect a simulated
> UART up to any of QEMU's "chardev" backends (eg to a TCP port,
> to the terminal, to a unix pipe), depending on what your needs
> are for the host end of the connection. Check the documentation
> for details.
> 
> thanks
> -- PMM
>