[okl4-developer] serial driver l4_kdb

[Lukas HANEL]

Hi Geoffrey

Geoffrey Lee wrote:
> Output via kdb can go out in one of the following two ways:
>
> (1) your printf() or whatever libc print function gets routed to
> libs/c/sys-*/ which ends up calling the kdb character print
> functions, or you implement your own such as print function
> and end up calling the kdb character print functions directly
>   
In this case, how/where is the kernel/userland boundary crossed?

> (2) you use vserial for your i/o.  In this instance you don't
> really care what the backend is.  If you choose to use l4kdb_uart,
> it will do a cheesy emulation of a serial device, enough to
> read and write, anyway.
>   
Using vserial for my i/o means I do not use printf?
In fact I am now testing the functionality of my serial driver and have
not yet found a way to send data via the vserial interface. How would I
do this?

Also, I am facing a problem with the kernel console. Iguana and the
Kernel use the same serial device, like in gumstix. When I send a char,
I get an interrupt delivered to my driver, but the data register of the
device is already empty. If, in the kernel's console.cc/get_c() function
I disable the reading of this register, it works. I programmed the
kernel timer for a 10ms tick.
Do you have an idea what I could do? E.g. is it possible to have kernel
and iguana use the same serial device?

Congrats to the wiki page,
Lukas Hänel