Xscale UART detection false positive

The following code from autoconfig_16550a() incorrectly determines that
the UARTS in the Tundra TSI108 are Xscale UARTS and misconfigures them.

>       /*
>        * Try writing and reading the UART_IER_UUE bit (b6).
>        * If it works, this is probably one of the Xscale platform's
>        * internal UARTs.
>        * We're going to explicitly set the UUE bit to 0 before
>        * trying to write and read a 1 just to make sure it's not
>        * already a 1 and maybe locked there before we even start start.
>        */
>       iersave = serial_in(up, UART_IER);
>       serial_outp(up, UART_IER, iersave & ~UART_IER_UUE);
>       if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
>               /*
>                * OK it's in a known zero state, try writing and reading
>                * without disturbing the current state of the other bits.
>                */
>               serial_outp(up, UART_IER, iersave | UART_IER_UUE);
>               if (serial_in(up, UART_IER) & UART_IER_UUE) {
>                       /*
>                        * It's an Xscale.
>                        * We'll leave the UART_IER_UUE bit set to 1 (enabled).
>                        */
>                       DEBUG_AUTOCONF("Xscale ");
>                       up->port.type = PORT_XSCALE;
>                       up->capabilities |= UART_CAP_UUE;
>                       return;
>               }
>       } else {
>               /*
>                * If we got here we couldn't force the IER_UUE bit to 0.
>                * Log it and continue.
>                */
>               DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
>       }
>       serial_outp(up, UART_IER, iersave);

Right now, I work around this by ifdeffing out that code.
Any ideas on alternative methods for autodetecting Xscale UARTS?

Dale Farnsworth
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