[U-Boot] [PATCH] include/ns16550.h: Unify structure declaration for registers

[Shinya Kuribayashi]

Detlev-san,

Detlev Zundel wrote:
> Instead of special casing the different access patterns, use common
> code with light macros sprinkled in to accomodate for the different
> layouts of the register structure.
> 
> Note that this also changes the types of the registers for the
> "positively packed (>1)" cases.  As the registers truly are unsigned
> chars, this is surely the Right Thing, but it is a semantic change.
> Note that for this case depending on the endianness on the bus, we may
> see a change of behaviour.
> 
> Signed-off-by: Detlev Zundel <dzu at denx.de>
> ---
>  include/ns16550.h |  130 +++++++++++++++--------------------------------------
>  1 files changed, 37 insertions(+), 93 deletions(-)
> 
> 
> Note, that I checked that the offsets are ok in the used cases
> switching from the old to the new code.  They *do* shift however in
> the positive packed cases, because the old code uses data types
> different than unsigned char.  Note that doing this, I also noticed
> that using "unsigned long" for 4 byte registers is also no longer true
> on 64-bit architectures.  One more reason to change the code.
> 
> Apart from that the code was also compile tested on several
> configurations using different REG_SIZES and compiles without
> warnings.  The special interesting case of +4 was successfully tested
> on CU824.

My hardware required 32-bit word access to NS16550 registers due to
byte-enable-lane reason (note that it's different from endian-ness).

I mean,

struct NS16550 {
    unsigned char rbr;
    unsigned char postpad_rbr[15];
        :
        :
};

if different from

struct NS16550 {
    unsigned long rbr;
    unsigned long postpad_rbr[3];
        :
        :
};

, at least for my hardware.

How do I supposed to configure UART in my board config file?

  Shinya