[U-Boot] [PATCH 3/3] nds32: asm/io.h: add __iormb and __iowmb support

[Graeme Russ]

Hi Macpaul

On Wed, Oct 26, 2011 at 4:19 PM, 馬克泡 <macpaul at gmail.com> wrote:
> Hi Graeme,
>
> 2011/10/25 馬克泡 <macpaul at gmail.com>:
>> Hi Marek,
>>
>> 2011/10/25 Marek Vasut <marek.vasut at gmail.com>:
>>
>> [snip]
>>
>> Please check ns16550.c, current code has another such kind of casting
>> #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
>> #define serial_out(x, y)        outb(x, (ulong)y)
>> #define serial_in(y)            inb((ulong)y)
>> [...]
>> #else
>> #define serial_out(x, y)        writeb(x, y)
>> #define serial_in(y)            readb(y)
>> #endif
>>
>
> I'm going to change writeb/readb series functions from macro into
> inline functions.

For all arches? Have you seen /arch/x86/include/asm/io.h?

> However, I've found data type casting problem in NS16550.
> Only here the serial_out with CONFIG_SYS_NS16550_PORT_MAPPED is used
> for board "eNET".
> Is this a necessary for this machine  to access 8-bytes data?

outb/inb access 8-bit data in a 16-bit address space and the ns16650 has
(for the x86 architecture at least) byte aligned registers

> Since inline functions are type sensitive,
> I've suggest to replace the macro for other machines like writeb(x, (uint)y)
> but Marek think this is not good enough.
> Could you give some comments?

Hmm, but eNET (well, all x86 really) would not use writeb/readb - outb/inb
would be used instead so if you are only touching the writeb/readb, eNET
would never see this. So I don't understand where your type conflicts are
occuring

Looking at the ulong cast, I was wondering why it was there, and the commit
diff says I wrote it which is a bit of a worry :) x86 only has 65535
ports accessible via outb and inb, so I would have thought the case should
have been a ushort, not a ulong.

I'm sorry, but without a patch to see what you are actually doing, I'm
having a bit of difficulty picturing what is happening and what could be
going wrong...

Regards,

Graeme