Re: [ECOS] Ethernet and Serial drivers for Linux target?

[Grant Edwards <grante@visi.com>]

On Thu, Nov 11, 1999 at 05:10:35PM +0000, Jonathan Larmour wrote:
> Grant Edwards wrote:
> > 
> > I told management that it should be possible to write serial port and
> > Ethernet device drivers for the Linux eCos target, thus allowing
> > people to do eCos application development on Linux boxes.  Of course
> > the performance and timing won't be the same, but for basic application
> > functionality it should be good enough for many things.
> > 
> > Has anybody done this?  I assume that all you have to do is to map
> > cyg_io_read() and cyg_io_write() into read() and write() calls, and
> > map cyg_io_get_config() and cyg_io_set_config() into appropriate
> > ioctl() calls?
> 
> One other issue that no-one else has mentioned is that you can't make calls
> to the system read() and write(), ioctl() etc. directly. To do that would
> involve linking with glibc, and that would simply not work.

I presume I could grab the source for Linux glibc read() write() and
ioctl(), strip out the stuff I don't need, and impliment my own
eCos-friendly versions of those calls...

> Instead all the current interfacing is done using kernel system calls
> directly. 

Ah. That's one question about which I had begun to wonder.  I haven't
looked at Linux system calls very closely, but there shouldn't be that
much of a difference in abstraction bewteen what the kernel provides
and what I need to make an eCos serial driver work.  

> Of course, this doesn't prevent you having a separate native linux
> program acting as a server for the client requests, communicating using
> fd's. And that's where Bart's solution would come in, in the thread in
> October he mentioned.

I suppose I could also just use the eCos 16550 driver and diddle the
hardware directly, but I'd rather let the Linux drivers worrry about
that so that I can utilize other types of serial ports.

-- 
Grant Edwards