From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfgang Denk <wd@denx.de>
Date: Sat, 14 Aug 2010 23:47:38 +0200
Subject: [U-Boot] Struct SoC access
In-Reply-To: <4C66F54D.2060701@emk-elektronik.de>
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	<20100814184641.981AC1606A5@gemini.denx.de>
	<4C66EECA.5020509@emk-elektronik.de>
	<20100814194117.982C71606A5@gemini.denx.de>
	<4C66F54D.2060701@emk-elektronik.de>
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Dear Reinhard Meyer,

In message <4C66F54D.2060701@emk-elektronik.de> you wrote:
>
> >> I was even thinking of something like
> >>
> >> struct soc {
> >> 	u32 xyz[0x80];	/* XYZ unit */
> >> 	u32 dbu[0x80];	/* Debug Unit */
> >> 	u32 rstc[0x80];	/* Reset Controller */
> >> and so on.
> > 
> > This is what PPC used to do; I like that - but ARM people always
> > explained to me that it makes no sense because address space on ARM
> > SoC is only sparely populated.
> 
> Even if, that's no reason, on can write "u32 spi0[0x1000]", on AT91
> the spacing of peripherals is 0x4000 bytes, in fact it repeats
> times in its window. The system stuff is like one peripheral with
> its components spaced by 0x200 bytes (hence the 0x80 above).

I think we have a misunderstaning ehre - I thought the entries like
"xyz" were indeed "u32" types - buut now I get the impression that
what you have in mind is that they are actually structs describing
hardware blocks.

Then it should be written like that.

For example, see file "arch/powerpc/include/asm/8xx_immap.h":

struct immap is what corresponds to your struct soc above.

> Would the toolchain "gulp" when one defines the whole 4 GB that way?

Why not?

Best regards,

Wolfgang Denk

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