[U-Boot] [PATCH] Enable port-mapped access to 16550 UART

[Detlev Zundel <dzu@denx.de>]

Hello Graeme,

> This patch does two things:
>   - Changes default behaviour to use proper memory accessors
>   - Allows port-mapped access (using inb/outb) for the x86 architecture
>
> Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
> ---
>  drivers/serial/ns16550.c |   69 ++++++++++++++++++++++++++--------------------
>  1 files changed, 39 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index 2fcc8c3..c41ca0d 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -6,6 +6,8 @@
>  
>  #include <config.h>
>  #include <ns16550.h>
> +#include <linux/types.h>
> +#include <asm/io.h>
>  
>  #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
>  #define UART_MCRVAL (UART_MCR_DTR | \
> @@ -13,28 +15,35 @@
>  #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
>  		     UART_FCR_RXSR |	\
>  		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
> +#ifdef CONFIG_X86
> +#define uart_writeb(x,y)	outb(x,(ulong)y)
> +#define uart_readb(y)		inb((ulong)y)
> +#else
> +#define uart_writeb(x,y) writeb(x,y)
> +#define uart_readb(y) readb(y)
> +#endif

Why do you need a specific variant for X86 instead of implementing
writeb and readb correctly in the first place?

If this was in place, all the accessors should only switch to using
readb/writeb and from looking at it, this should not brak e.g. PowerPC
boards with weird register layouts.

When you post a patch with only these changes, I'll test it on a few of
the usual suspects on PowerPC.

Cheers
  Detlev

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