Re: [PATCH v1 14/16] drivers/vuart: move simple MMIO-based UART emulator

[dmkhn@xxxxxxxxx]

On Tue, Jun 24, 2025 at 09:40:02AM +0200, Jan Beulich wrote:
> On 24.06.2025 09:36, dmkhn@xxxxxxxxx wrote:
> > On Tue, Jun 24, 2025 at 07:53:04AM +0200, Jan Beulich wrote:
> >> On 24.06.2025 05:57, dmkhn@xxxxxxxxx wrote:
> >>> --- a/xen/drivers/vuart/Kconfig
> >>> +++ b/xen/drivers/vuart/Kconfig
> >>> @@ -3,6 +3,15 @@ config HAS_VUART
> >>>
> >>>  if (ARM_32 || ARM_64)
> >>>
> >>> +config HAS_VUART_MMIO
> >>> + bool "Simple MMIO-based emulated UART support"
> >>
> >> Perhaps in a separate change this should be renamed. HAS_* should never
> >> have prompts.
> >
> > Oh, so HAS_ flags are non-interactive selectors by design?
> 
> Well "has" simply by the word means "this is available". Any user-selectable 
> item
> deriving from the mere availability would then have a "depends on HAS_...", 
> thus
> hiding the option in situation where the functionality isn't available (be it 
> per
> arch or for other reasons).

I see there's a lot of drivers (UARTs) which are selectable by the user via
HAS_ symbols (drivers/char/Kconfig), e.g:

CONFIG_HAS_NS16550:                                                             
                                                                                
                                           │  
  │                                                                             
                                                                                
                                               │  
  │ This selects the 16550-series UART support. For most systems, say Y.        
                                                                                
                                               │  
  │                                                                             
                                                                                
                                               │  
  │ Symbol: HAS_NS16550 [=y]                                                    
                                                                                
                                               │  
  │ Type  : bool                                                                
                                                                                
                                               │  
  │ Prompt: NS16550 UART driver                                                 
                                                                                
                                               │  
  │   Location:                                                                 
                                                                                
                                               │  
  │     -> Device Drivers                                                       
                                                                                
                                               │  
  │   Defined at drivers/char/Kconfig:4 

> 
> Jan