Subject: Re: [PATCH 1/2] Define FIXED_PORT flag for serial_core

From: Alan <[email-masked]>
Date: Tue, 20 Feb 2007 13:07:01 +0000

On Tue, 20 Feb 2007 14:19:51 +1100 (EST)
David Gibson <[email-masked]> wrote:

> At present, the serial core always allows setserial in userspace to
> change the port address, irq and base clock of any serial port.  That
> makes sense for legacy ISA ports, but not for (say) embedded ns16550
> compatible serial ports at peculiar addresses.  In these cases, the
> kernel code configuring the ports must know exactly where they are,
> and their clocking arrangements (which can be unusual on embedded
> boards).  It doesn't make sense for userspace to change these
> settings.
> 
> Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port
> structure.  If this flag is set when the serial port is configured,
> any attempts to alter the port's type, io address, irq or base clock
> with setserial are ignored.
> 
> In addition this patch uses the new flag for on-chip serial ports
> probed in arch/powerpc/kernel/legacy_serial.c, and for other
> hard-wired serial ports probed by drivers/serial/of_serial.c.
> 
> Signed-off-by: David Gibson <[email-masked]>
>
Acked-by: Alan Cox <[email-masked]>