Subject: [PATCH] imx: add polled io uart methods

From: [email-masked] (Saleem Abdulrasool)
Date: Tue, 18 Oct 2011 20:52:49 -0700

On Tue, 18 Oct 2011, Uwe Kleine-K?nig wrote:

> On Sun, Oct 16, 2011 at 08:22:01PM -0700, Saleem Abdulrasool wrote:
> > These methods are invoked if the iMX uart is used in conjuction with kgdb during
> > early boot.  In order to access the UART without the interrupts, the kernel uses
> > the basic polling methods for IO with the device.  With these methods
> > implemented, it is now possible to enable kgdb during early boot over serial.
> > 
> > Signed-off-by: Saleem Abdulrasool <[email-masked]>
> > ---
> >  drivers/tty/serial/imx.c |   77 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 files changed, 77 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> > index 7e91b3d..4fcf9ca 100644
> > --- a/drivers/tty/serial/imx.c
> > +++ b/drivers/tty/serial/imx.c
> > @@ -102,6 +102,7 @@
> >  #define  UCR2_STPB       (1<<6)	 /* Stop */
> >  #define  UCR2_WS         (1<<5)	 /* Word size */
> >  #define  UCR2_RTSEN      (1<<4)	 /* Request to send interrupt enable */
> > +#define  UCR2_ATEN       (1<<3)  /* Aging Timer Enable */
> >  #define  UCR2_TXEN       (1<<2)	 /* Transmitter enabled */
> >  #define  UCR2_RXEN       (1<<1)	 /* Receiver enabled */
> >  #define  UCR2_SRST 	 (1<<0)	 /* SW reset */
> > @@ -1075,6 +1076,77 @@ imx_verify_port(struct uart_port *port, struct serial_struct *ser)
> >  	return ret;
> >  }
> >  
> > +
> needless newline

Removed.

> > +#if defined(CONFIG_CONSOLE_POLL)
> > +static int imx_poll_get_char(struct uart_port *port)
> > +{
> > +	volatile unsigned int status;
> Why is that volatile?

It shouldnt be, removed the volatile attribute.  Im not sure why that was there,
it really doesnt make any sense since there isnt any inline assembler there to
confuse the compiler.

> > +	unsigned int cr1, cr2, cr3;
> > +	unsigned char c;
> > +
> > +	/* save control registers */
> > +	cr1 = readl(port->membase + UCR1);
> > +	cr2 = readl(port->membase + UCR2);
> > +	cr3 = readl(port->membase + UCR3);
> > +
> 
> Best regards
> Uwe

Thanks for the review.  Ive not attached the updated patch since Id like to make
the changes that Sascha suggested, and I shall post the updated patch
subsequently.

> -- 
> Pengutronix e.K.                           | Uwe Kleine-K?nig            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |

-- 
Saleem Abdulrasool
compnerd (at) compnerd (dot) org