Re: [PATCH 4/5] tty/hw: move hardware drivers to drivers/tty/hw

Arnd Bergmann
2010-08-30T15:25:04Z

On Monday 30 August 2010, Mike Frysinger wrote:
>
> On Mon, Aug 30, 2010 at 08:28, Arnd Bergmann wrote:
> > On Monday 30 August 2010, Alan Cox wrote:
> >> > My impression was that it should actually be converted into an hvc
> >> > driver as a cleanup and moved to drivers/tty/hvc. It can probably
> >> > get reduced to one third of its size if you do that.
> >>
> >> Not sure it makes sense - hvc seems the wrong abstraction.
> >
> > It seems to be very similar to hvc_tile.c in purpose, which is
> > the most trivial driver we have. Why would that not work?
> >
> > Most of bfin_jtag_comm is about interfacing with the tty layer
> > and providing a kernel thread to do the polling, which is exactly
> > what hvc_console.c does.
>
> i have no idea what "hvc" is, but my limited knowledge was that it was
> for large powerpc servers, so i didnt bother looking at it too much.
> i simply wanted a way to create a tty on top of the hardware channel.
> if there is a framework that doesnt break this usage and lets me
> simplify my driver, then either works for me.

HVC started out as the console for large powerpc, but has turned into
a generic framework for TTY drivers that are based on simple read/write
operations with or without interrupts.

Please take a look at drivers/char/hvc_tile.c, which was added recently
for a scenario quite similar to yours (debug port, not irq).

Arnd