[Qemu-devel] Implementing new serial virtual HW w/ redirection

[Emmanuel Blot]

Hi All,

I'm new to the ML.

I've started to port Qemu to a new HW based on ARM926EJ-S core.
So far so good, I've implemented some basic HW (INT controller, System
register, UART, …)

I'd like to redirect the virtual serial port not to the current
default stdin/stdout of the Qemu
application, but to a (Unix) socket.
I'm not sure I'm looking at the proper solution, so any advice is welcomed.

AFAIU, I may define a Unix socket with the command line:
-chardev socket,id=sersok,path=~user/serialsocket,server,nowait

and assign the new virtual serial device (named new-uart hereafter):
-device new-uart,chardev=sersock

Is it the proper way to map the new virtual UART to the Unix socket?

My main question is about the driver implementation:
For the first implementation, I simply used
 * qdev_init_chardev
 * qemu_chr_add_handlers
 * qemu_chr_fe_write
calls to implement the virtual serial port. It works fine to print out
and read from the standard I/O, but I'm not sure to understand what I should
implement to use the chardev created from the command line rather than the
default standard I/O.

qdev_init_chardev() seems somewhat deprecated, as the implementation
contains the following comment:
    /* FIXME: This function needs to go away: use chardev properties!  */

Should I drop qdev_init_chardev() for another API?

I've looked at several examples on virtual serial port in existing Qemu drivers,
but I don't know what is the best and simplest way to go.

Any advice would be greatly appreciated,

Thanks,
Manu.