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From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] Struct SoC access
Date: Sat, 14 Aug 2010 23:47:38 +0200	[thread overview]
Message-ID: <20100814214738.0BEC81606A5@gemini.denx.de> (raw)
In-Reply-To: <4C66F54D.2060701@emk-elektronik.de>

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

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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is logical and beneficial. We cannot disregard that philosophy merely
for personal gain, no matter how important that gain might be.
	-- Spock, "Journey to Babel", stardate 3842.4

  parent reply	other threads:[~2010-08-14 21:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-14  9:07 [U-Boot] Make preparatory patches that initially have no effect? Reinhard Meyer
2010-08-14 14:30 ` Wolfgang Denk
2010-08-14 17:05   ` Reinhard Meyer
2010-08-14 18:46     ` Wolfgang Denk
2010-08-14 19:30       ` [U-Boot] Struct SoC access (was:Make preparatory patches that initially have no effect?) Reinhard Meyer
2010-08-14 19:36         ` Mike Frysinger
2010-08-14 19:40           ` [U-Boot] Struct SoC access Reinhard Meyer
2010-08-14 20:48             ` Mike Frysinger
2010-08-14 19:41         ` [U-Boot] Struct SoC access (was:Make preparatory patches that initially have no effect?) Wolfgang Denk
2010-08-14 19:58           ` [U-Boot] Struct SoC access Reinhard Meyer
2010-08-14 20:47             ` Reinhard Meyer
2010-08-14 21:49               ` Wolfgang Denk
2010-08-14 21:47             ` Wolfgang Denk [this message]
2010-08-14 22:15               ` Reinhard Meyer
2010-08-16 20:21                 ` Scott Wood
2010-08-17  6:58                   ` Reinhard Meyer

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