Re: [PATCH v2 02/15] serial: core: add uart_iotype_mmio/legacy_io helper functions

[Andy Shevchenko]

On Sun, May 03, 2026 at 12:25:24AM +0100, Maciej W. Rozycki wrote:
> On Thu, 30 Apr 2026, Andy Shevchenko wrote:
> 
> > > +bool uart_iotype_legacy_io(enum uart_iotype iotype)
> > 
> > Why do we use 'legacy'? Still in use in modern CPUs...
> 
>  Deprecated in PCIe and not available in numerous systems.  Also actually 
> called "legacy" in some serial port datasheets aged ~20 years now.  While 
> some contemporary CPUs indeed retain the port I/O address space, it's for 
> legacy use anyway, you don't want to rely on it in new designs.

For the holder of the new (modern) CPU which supports the IO ports, this is
definitely not a legacy interface despite on whatever PCIe or other datasheets
call it.

-- 
With Best Regards,
Andy Shevchenko