Re: [RFC PATCH] tty: serial: Add 8250-core based omap driver

["Lennart Sorensen" <lsorense@csclub.uwaterloo.ca>]

On Thu, Jul 03, 2014 at 02:48:08PM -0400, Lennart Sorensen wrote:
> On Wed, Jul 02, 2014 at 06:00:09PM +0200, Sebastian Andrzej Siewior wrote:
> > This patch provides a 8250-core based UART driver for the internal OMAP
> > UART. The longterm goal is to provide the same functionality as the
> > current OMAP uart driver and hopefully DMA support which could borrowed
> > from the 8250-core.
> 
> This sounds interesting.  We are currently finding the omap serial driver
> awefully slow at handling serial traffic with ti's 3.12.y kernel branch,
> while the 3.8.y was seemingly a bit better (on the dra7xx eval board).
> Haven't had time to really investigate that yet though.
> 
> > The whole PM-Runtime part is currently missing.
> > It has been only tested as console UART.
> > The tty name is ttyS based instead of ttyO. How big is the pain here,
> > what could be the easiest way to provide compatibility?
> 
> I would certainly love to see ttyS instead of ttyO.  But of course I am
> working on a new system that isn't released yet so changing things is
> a complete non issue for me. :)
> 
> I should give this driver a try and see how it compares so far.

I get a segfault at this line:

mvr = uart_read(up, UART_OMAP_MVER);

I added it to ti's 3.12.y kernel and ran it on uart7 and uart8 on
a dra7xx-evm as a module (built in the kernel never booted due to
the crash).

-- 
Len Sorensen