[U-Boot] [PATCH v2 3/5] dm: ns16550: Don't map_physmem for I/O ports

[Simon Glass]

Hi Paul,

On 16 May 2016 at 11:44, Paul Burton <paul.burton at imgtec.com> wrote:
> If the UART is to be accessed using I/O port accessors (inb & outb) then
> using map_physmem doesn't make sense, since it operates in a different
> memory space. Remove the call to map_physmem when
> CONFIG_SYS_NS16550_PORT_MAPPED is defined, allowing I/O port addresses
> to not be mangled by the incorrect mapping.
>
> Signed-off-by: Paul Burton <paul.burton at imgtec.com>
> ---
>
> Changes in v2:
> - New patch, part of a simplified approach tackling only a single Malta UART.
>
>  drivers/serial/ns16550.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index 28da9dd..e58e6aa 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -100,7 +100,11 @@ static void ns16550_writeb(NS16550_t port, int offset, int value)
>         unsigned char *addr;
>
>         offset *= 1 << plat->reg_shift;
> +#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
> +       addr = (unsigned char *)plat->base + offset;
> +#else
>         addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
> +#endif

Please don't add CONFIG #ifdefs in these functions. Perhaps it needs
to be another parameter? Possibly a flag. But with driver-model we
need to be able to support both options in the core code.

This driver is a real mess. I'm hoping we can simplify it once we have
everything on driver model.

>         /*
>          * As far as we know it doesn't make sense to support selection of
>          * these options at run-time, so use the existing CONFIG options.
> @@ -114,7 +118,11 @@ static int ns16550_readb(NS16550_t port, int offset)
>         unsigned char *addr;
>
>         offset *= 1 << plat->reg_shift;
> +#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
> +       addr = (unsigned char *)plat->base + offset;
> +#else
>         addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
> +#endif
>
>         return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
>  }
> --
> 2.8.2
>

Regards,
Simon