Re: [PATCH 2/2] tty/serial: at91: add a fallback option to determineuart/usart property

[Nicolas Ferre]

On 14/10/2013 15:59, Jean-Christophe PLAGNIOL-VILLARD :
> On 10:43 Thu 10 Oct     , Nicolas Ferre wrote:
> > On older SoC, the "name" field is not filled in the register map.
> > Fix the way to figure out if the serial port is an uart or an usart for these
> > older products (with corresponding properties).
> >
> > Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
> > ---
> >   drivers/tty/serial/atmel_serial.c | 19 ++++++++++++++++++-
> >   include/linux/atmel_serial.h      |  1 +
> >   2 files changed, 19 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> > index 6b0f75e..c7d99af 100644
> > --- a/drivers/tty/serial/atmel_serial.c
> > +++ b/drivers/tty/serial/atmel_serial.c
> > @@ -99,6 +99,7 @@ static void atmel_stop_rx(struct uart_port *port);
> >   #define UART_PUT_RTOR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_RTOR)
> >   #define UART_PUT_TTGR(port, v)	__raw_writel(v, (port)->membase + ATMEL_US_TTGR)
> >   #define UART_GET_IP_NAME(port)	__raw_readl((port)->membase + ATMEL_US_NAME)
> > +#define UART_GET_IP_VERSION(port) __raw_readl((port)->membase + ATMEL_US_VERSION)
> >
> >    /* PDC registers */
> >   #define UART_PUT_PTCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
> > @@ -1503,6 +1504,7 @@ static void atmel_get_ip_name(struct uart_port *port)
> >   {
> >   	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> >   	int name = UART_GET_IP_NAME(port);
> > +	u32 version;
> >   	int usart, uart;
> >   	/* usart and uart ascii */
> >   	usart = 0x55534152;
> > @@ -1517,7 +1519,22 @@ static void atmel_get_ip_name(struct uart_port *port)
> >   		dev_dbg(port->dev, "This is uart\n");
> >   		atmel_port->is_usart = false;
> >   	} else {
> > -		dev_err(port->dev, "Not supported ip name, set to uart\n");
> > +		/* fallback for older SoCs: use version field */
> > +		version = UART_GET_IP_VERSION(port);
> > +		switch (version) {
> > +		case 0x302:
> > +		case 0x10213:
> > +			dev_dbg(port->dev, "This version is usart\n");
> > +			atmel_port->is_usart = true;
> > +			break;
> > +		case 0x203:
> > +		case 0x10202:
> > +			dev_dbg(port->dev, "This version is uart\n");
> > +			atmel_port->is_usart = false;
> > +			break;
> > +		default:
> > +			dev_err(port->dev, "Not supported ip name nor version, set to uart\n");
>
> it's not really an error a dev_warn is more oppropriate

As we are already in -rc5 and that these fixes are critical for at91 
platforms, I will not re-spin another patch just for this.

Moreover, I have the feeling that if we end up in this case, it means 
that we are in big troubles because the usart/uart included in the 
product triggering this log is not known (I recall that newer products 
do not have to hit these lines of code).

With these 2 reasons, I prefer to keep my patch like it is.

Greg, can you consider taking these two patches as regression fixes for 
3.12 (with Tested-by tag from Thomas)?

Thanks, bye,

> > +		}
> >   	}
> >   }
> >
> > diff --git a/include/linux/atmel_serial.h b/include/linux/atmel_serial.h
> > index be201ca..00beddf 100644
> > --- a/include/linux/atmel_serial.h
> > +++ b/include/linux/atmel_serial.h
> > @@ -125,5 +125,6 @@
> >   #define ATMEL_US_IF		0x4c			/* IrDA Filter Register */
> >
> >   #define ATMEL_US_NAME		0xf0			/* Ip Name */
> > +#define ATMEL_US_VERSION	0xfc			/* Ip Version */
> >
> >   #endif
> > --
> > 1.8.2.2


--
Nicolas Ferre
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