[U-Boot] [PATCH 12/26] [ns16550] Enable port-mapped access

[Nishanth Menon]

On 04/11/2010 08:07 AM, Graeme Russ wrote:
> Nishanth Menon wrote:
>> On 04/11/2010 07:43 AM, Graeme Russ wrote:
>>> The x86 architecture exclusively uses Port-Mapped I/O (inb/outb) to
>>> access
>>> the 16550 UARTs. This patch mimics how Linux selects between
>>> Memory-Mapped
>>> and Port-Mapped I/O. This allows x86 boards to use CONFIG_SERIAL_MUTLI
>>> and
>>> drop the custom serial port driver
>> [...]
>>
> <snip>
>>> +#ifdef CONFIG_X86
>>> +#define serial_out(x,y)    outb(x,(ulong)y)
>>> +#define serial_in(y)    inb((ulong)y)
>>> +#else
>>> +#define serial_out(x,y) writeb(x,y)
>>> +#define serial_in(y)     readb(y)
>>> +#endif
>>
>> wont it be nice if we have:
>> CONFIG_NS16550_PORT_MAPPED
>> CONFIG_NS16550_MEMORY_MAPPED
>> ? rather than being tied to x86?
> <snip>
>
> Hmm, true. Or maybe CONFIG_SYS_NS16550_PORT_MAPPED instead of
> CONFIG_X86 so the default of memory mapped is silently retained
>
> I think CONFIG_SYS is more appropriate as per the README:
>
> * Configuration _SETTINGS_:
>    These depend on the hardware etc. and should not be meddled with if
>    you don't know what you're doing; they have names beginning with
>    "CONFIG_SYS_".
>
That does sound good.. thanks..
Regards,
Nishanth Menon