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Re: [PATCH] serial driver PMC MSP71xx, kernel linux-mips.git mast er

To: Marc St-Jean <Marc_St-Jean@pmc-sierra.com>
Subject: Re: [PATCH] serial driver PMC MSP71xx, kernel linux-mips.git mast er
From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Date: Fri, 16 Feb 2007 20:21:31 +0300
Cc: Marc St-Jean <stjeanma@pmc-sierra.com>, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, linux-serial@vger.kernel.org
In-reply-to: <45D5E4A7.3070807@pmc-sierra.com>
Organization: MontaVista Software Inc.
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <45D5E4A7.3070807@pmc-sierra.com>
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Hello.

Marc St-Jean wrote:

> diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
> index 3d91bfc..bfaacc5 100644
> --- a/drivers/serial/8250.c
> +++ b/drivers/serial/8250.c
> @@ -308,6 +308,7 @@ static unsigned int serial_in(struct uar
>               return inb(up->port.iobase + 1);
> > case UPIO_MEM:
> +     case UPIO_DWAPB:
>               return readb(up->port.membase + offset);
> > case UPIO_MEM32:
> @@ -333,6 +334,8 @@ #endif
>  static void
>  serial_out(struct uart_8250_port *up, int offset, int value)
>  {
> +     /* Save the offset before it's remapped */
> +     int save_offset = offset;
>       offset = map_8250_out_reg(up, offset) << up->port.regshift;
> > switch (up->port.iotype) {

I've just got an idea how to "beautify" this code -- rename the 'offset' arg to something like reg, and then declare/init 'offset' as local variable.
Would certainly look better (and worth doing in all serial_* accessros).

I agree but am having enough of a hard time getting the bare minimum
accepted that I don't dare touch any unnecessary lines.

Well, I can try pushing this simple cleanup myself... seems worth doing for alike future cases anyway.

> @@ -359,6 +362,18 @@ #endif
>                       writeb(value, up->port.membase + offset);
>               break;
> > + case UPIO_DWAPB:
> +             /* Save the LCR value so it can be re-written when a
> +              * Busy Detect interrupt occurs. */
> +             if (save_offset == UART_LCR)
> +                     up->lcr = value;
> +             writeb(value, up->port.membase + offset);
> +             /* Read the IER to ensure any interrupt is cleared before
> +              * returning from ISR. */
> +             if (save_offset == UART_TX || save_offset == UART_IER)
> +                     value = serial_in(up, UART_IER);
> +             break;
> + > default:
>               outb(value, up->port.iobase + offset);
>       }
> @@ -2454,8 +2485,8 @@ int __init serial8250_start_console(stru
> > add_preferred_console("ttyS", line, options);
>       printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",
> -             line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",
> -             port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :
> +             line, port->iotype >= UPIO_MEM ? "MMIO" : "I/O port",
> +             port->iotype >= UPIO_MEM ? (unsigned long) port->mapbase :
>                   (unsigned long) port->iobase, options);
>       if (!(serial8250_console.flags & CON_ENABLED)) {
>               serial8250_console.flags &= ~CON_PRINTBUFFER;

   I've remembered why I decided not to fix it: this code only gets called
from 8250__eraly.c which can't handle anything beyond UPIO_MEM anyway.

We don't use 8250_early and I've tested it works without, so I'll drop this
change.

   No need I guess since this is the Right Thing (TM) anyway.

Thanks,
Marc

WBR, Sergei

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